ORCID Profile
0000-0002-6814-4997
Current Organisation
University of South Australia
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Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.BANDL.2015.04.004
Abstract: The developmental trajectory of language lateralisation over the preschool years is unclear. We explored the relationship between lateralisation of cerebral blood flow velocity response to object naming and cognitive performance in children aged 1-5 years. Functional transcranial Doppler ultrasound was used to record blood flow velocity bilaterally from middle cerebral arteries during a naming task in 58 children (59% male). At group level, the Lateralisation Index (LI) revealed a greater relative increase in cerebral blood flow velocity within the left as compared to right middle cerebral artery. After controlling for maternal IQ, left-lateralised children displayed lower expressive language scores compared to right- and bi-lateralised children, and reduced variability in LI. Supporting this, greater variability in lateralised response, rather than mean response, was indicative of greater expressive language ability. Findings suggest that a delayed establishment of language specialisation is associated with better language ability in the preschool years.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2014
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 22-01-2008
Publisher: JMIR Publications Inc.
Date: 29-12-2019
Abstract: pathy is a common symptom in neurological disorders, including dementia, and is associated with a faster rate of cognitive decline, reduced quality of life, and high caregiver burden. There is a lack of effective pharmacological treatments for apathy, and nonpharmacological interventions are a preferred first-line approach to treatment. Virtual reality (VR) using head-mounted displays (HMDs) is being successfully used in exposure- and distraction-based therapies however, there is limited research on using HMDs for symptoms of neurological disorders. his feasibility study aimed to assess whether VR using HMDs could be used to deliver tailored reminiscence therapy and examine the willingness to participate, response rates to measures, time taken to create tailored content, and technical problems. In addition, this study aimed to explore the immediate effects between verbal fluency and apathy after exposure to VR. mixed methods study was conducted in a s le of older adults residing in aged care, and 17 participants were recruited. Apathy was measured using the Apathy Evaluation Scale (AES), and verbal fluency was used as a proxy measure of improvements in apathy and debriefing interviews to assess feedback from participants. Side effects that can occur from using HMDs were also measured. e recruited participants from a high socioeconomic status setting with a high education level, and the participation rate was 85% (17/20) most responses to measures were positive. Access to a wide range of freely available content and the absence of technical difficulties made the delivery of a VR reminiscence intervention highly feasible. Participants had improved semantic scores ( i t /i sub /sub =−3.27 i P /i =.006) but not phonemic fluency scores ( i t /i sub /sub =0.55 i P /i =.59) immediately after the intervention. Those with higher levels of apathy demonstrated the greatest cognitive improvements after a VR reminiscence experience, which was indicated by a strong positive relationship between the AES and semantic verbal fluency change scores postminus pre-VR ( i r /i =0.719 95% CI 0.327 to 0.900 i P /i =.003). All participants enjoyed the experience despite 35% (6/17) of participants experiencing temporary side effects. his study provides initial evidence that it is feasible to use VR with HMDs for therapy to treat symptoms of apathy in older adults in residential aged care. However, there is a need to closely monitor the side effects of HMD use in older adults. Further research is needed using an active control group to compare the use of VR with traditional forms of reminiscence therapy.
Publisher: Springer Science and Business Media LLC
Date: 11-09-2020
DOI: 10.1038/S41598-020-71800-6
Abstract: Higher and lower levels of alertness typically lead to a leftward and rightward bias in attention, respectively. This relationship between alertness and spatial attention potentially has major implications for health and safety. The current study examined alertness and spatial attention under simulated shiftworking conditions. Nineteen healthy right-handed participants (M = 24.6 ± 5.3 years, 11 males) completed a seven-day laboratory based simulated shiftwork study. Measures of alertness (Stanford Sleepiness Scale and Psychomotor Vigilance Task) and spatial attention (Landmark Task and Detection Task) were assessed across the protocol. Detection Task performance revealed slower reaction times and higher omissions of peripheral (compared to central) stimuli, with lowered alertness suggesting narrowed visuospatial attention and a slight left-sided neglect. There were no associations between alertness and spatial bias on the Landmark Task. Our findings provide tentative evidence for a slight neglect of the left side and a narrowing of attention with lowered alertness. The possibility that one’s ability to sufficiently react to information in the periphery and the left-side may be compromised under conditions of lowered alertness highlights the need for future research to better understand the relationship between spatial attention and alertness under shiftworking conditions.
Publisher: SAGE Publications
Date: 26-07-2020
Abstract: The aim of this study was to assess the long-term risk for mortality and incident dementia associated with exposure to intimate partner violence (IPV) at any time over the life course. Data were taken from the Australian Longitudinal Study of Women’s Health, a population-based cohort study initiated in 1996. Analysis is based on 12,085 community-dwelling women aged 70 to 75 years at baseline from all states and territories. Self-reported exposure to violence was separated into historical (any time before baseline), current (past 12 months), or both. Date of death was obtained from the National Death Index, and dementia status was self-reported or obtained from administrative data. We modeled mortality risk using Cox regression, and risk for incident dementia using Fine-Gray proportional hazards modeling with death as a competing risk. Follow up continued to December 2017. At baseline, 728 women (6.0%) reported historical IPV, 121 (1.0%) reported current violence, and 38 reported both (0.3%). Historical IPV increased 20-year mortality risk after controlling for demographic, socioeconomic, and lifestyle variables (hazard ratio 1.10, 95% confidence interval = [1.00, 1.20]). There was no relationship between current violence and mortality (hazard ratio 1.04, 95% confidence interval = [0.85, 1.29]). There was also no association between IPV and risk for incident dementia (hazard ratio 1.02, 95% confidence interval = [0.89, 1.17]). Older women who self-report exposure to IPV over the lifespan die significantly earlier than women who do not. Further research that considers the mediating role of psychological trauma is needed to examine the relationship between IPV and dementia.
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.EXGER.2022.111971
Abstract: People's perceptions of the mental effort required for everyday activities may drive variation in the relationships between lifestyles and cognitive ability. We asked n = 259 healthy older adults aged 60 to 70 years (90 males, 169 females) to provide a rating of the Perceived Mental Effort (PME) for each activity instance they recalled over a 48-h period as part of a time-use recall. PME was rated on a 9-point scale from "very, very low" (score of 1) to "very, very high" (score of 9). Across the entire s le, participants rated a total of 196 different activities and 17,433 activity instances. The mean PME for in idual activities was 3.50 ± 1.58. PMEs varied significantly by activity domain, with highest ratings being for Work (5.48 ± 1.72) and the lowest for Self-Care (2.89 ± 0.98). In multivariate analyses, PME ratings were higher in males than females (+0.30), PMEs were higher later in the day, increased with task duration, and decreased with age (all p < 0.0001). Time-weighted average in idual PMEs across the two days of recall ranged from 1.86 to 6.50, and were 0.3 units higher for males, but unrelated to age. Repeated intra-in idual PME ratings for the same activity were very reliable (ICC = 0.995, mean absolute difference = 0.03 ± 0.17). PMEs show promise as a reliable measure of mental effort.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.BANDC.2018.12.006
Abstract: This study investigated electroencephalography (EEG) correlates of prediction error during probabilistic learning in pre-adolescents. The detection of prediction errors, the discrepancies between experienced and anticipated outcomes, is thought to be a critical mechanism that drives new learning. Thirty-three typically developing pre-adolescents (mean age = 10.62 years) participated in an associative learning task in which they learned the probabilistic relationships between cues and outcome stimuli in the absence of explicit feedback. We investigated whether three outcome-locked event-related potentials (ERPs) could reflect prediction error processing: the P3, the late positive potential (LPP), and the feedback-related negativity (FRN). All ERP components investigated were sensitive to the magnitude of hypothetical prediction errors that were estimated based on each in idual's learning performance. Higher estimated prediction errors generated larger P3 and LPP components, and a more negative FRN. These findings indicate that pre-adolescents are capable of undergoing probabilistic learning in the absence of explicit feedback, much in the same way as adults, and that prediction error processing is physiologically indexed via the FRN, P3 and LPP following outcome stimuli.
Publisher: Wiley
Date: 10-09-2005
DOI: 10.1207/S15516709COG0000_26
Abstract: This study investigated whether brain neural activity that accompanied the processing of previously learned map information was influenced by the modality in which the spatial parameters of the maps were originally learned. Participants learned a map by either viewing it directly or by reading an equivalent verbal description. Following learning, the participants' ability to use their spatial knowledge was tested in a spatial orientation task. Electrophysiological recordings identified significant effects of prior learning modality on event-related brain activity within 300 ms following the presentation of map orientation instructions. The results indicate that modality-specificity in spatial memory is present at a very early stage of processing.
Publisher: Elsevier BV
Date: 05-2008
DOI: 10.1016/J.BIOPSYCH.2007.11.022
Abstract: In addition to cognitive impairment, there are disruptions to mood and emotion processing in attention-deficit/hyperactivity disorder (ADHD) but little is known about their neural basis. We examined ADHD disturbances in mood and emotion recognition and underlying neural systems before and after treatment with stimulant medication. Participants were 51 unmedicated ADHD adolescents and 51 matched healthy control subjects rated for depressed and anxious mood and accuracy for identifying facial expressions of basic emotion. Brain function was recorded using event-related potentials (ERPs) while subjects viewed these expressions. ADHD subjects were retested after 4 weeks, following treatment with methylphenidate (MPH). ADHD subjects showed a profile of emotion-related impairment: higher depression and anxiety, deficits in identifying threat-related emotional expressions in particular, and alterations in ERPs. There was a pronounced reduction in occipital activity during the early perceptual analysis of emotional expression (within 120 msec), followed by an exaggeration of activity associated with structural encoding (120-220 msec) and subsequent reduction and slowing of temporal brain activity subserving context processing (300-400 msec). Methylphenidate normalized neural activity and produced some improvement of emotion recognition but had no impact on negative mood. Improvements in neural activity with MPH were consistent predictors of improvement in clinical features of emotional lability and hyperactivity. Objective behavioral and brain function measures of emotion processing may provide a valuable addition to the clinical armamentarium for assessing emotional disturbances in ADHD and the efficacy of stimulants for treating these disturbances.
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.IJPSYCHO.2015.02.030
Abstract: Neural adaptation paradigms have been used in the electrophysiological and neuroimaging literature to characterise neural populations underlying face and object perception. It was recently reported by Nemrodov and Itier (2012) that adaptation of the N170 event-related potential (ERP) component is not stimulus category-specific over rapid adapting stimulus durations (S1 durations) and interstimulus intervals (ISIs). We therefore tested the category-specificity of adaptation over a range of S1 durations and ISIs. Faces and chairs were presented at S1 (for 200, 500 or 1000 ms) and S2 (for 200 ms), over a variable ISI (200 or 500 ms). Mean litudes of the P1, N170 and P2 visual ERP components were measured following S1 and S2 stimuli. Faces at S1 led to the smallest (i.e., most adapted) N170 litudes to both faces and chairs at S2, more than chairs at S1. N170s at S2 were smallest after a 500ms S1 duration but N170 litude did not vary over ISI. Effects were also seen for the two surrounding positive components, the P1 and P2. Presenting faces at S1 led to enhanced P1 litudes evoked by S2 chair stimuli. The P2 showed the smallest litudes following the shorter 200 ms ISI. These results indicate that adaptation of the N170 is not actually category-specific but instead dependent on the S1 category (regardless of S2 category), and may also be influenced by earlier effects at the P1 (i.e., not specific to the N170). This challenges the assumption that N170 category adaptation indexes effects on distinct neural populations that differ between faces and non-face objects.
Publisher: American Society of Consultant Pharmacists
Date: 12-2020
Abstract: Depression in late life is associated with poorer quality of life and higher mortality. Pain, chronic illness, loneliness, loss of physical abilities, grief, cognitive impairment, and socioeconomic disadvantage all increase the risk of depression in this age group. Treatment for depression in late life includes antidepressant medications, cognitive behavior therapy, interpersonal therapy, and electroconvulsive therapy. The use of virtual reality is also proposed as a potential new treatment for depression that could be made available in aged care settings, and early evidence holds promise. Differentiating between depression, dementia, and delirium plays an important role in diagnosis and treatment, and often relies on a comprehensive neuropsychological assessment. The prevention and treatment of depression in late life requires collaboration and cooperation between families, carers, health professionals, and aged care providers.
Publisher: Springer Science and Business Media LLC
Date: 11-12-2018
DOI: 10.1007/S00221-018-5449-2
Abstract: When thinking about quantifiable domains such as numbers, pitch, and size, they are implicitly mapped on to representational space with small/low/less and large/high/more of the respective domain represented on the left and right sides of representational space, respectively. Recent research has also demonstrated that more abstract domains (colours, language, political party names) are also mapped in the same way. This study investigated a new abstract domain, risk, to examine if this same pattern of effects is apparent (left = low risk/right = high risk) to get a better understanding of how risk magnitudes are processed. Experiment 1 (n = 26) presented objective, statistically calculated risk stimuli (micromorts) to participants, who indicated if the stimuli had lower or higher risks than a referent, with their left and right hands. Experiment 2 (n = 25) utilised the same task, but the risk stimuli were generated by the participants themselves. Both experiments found the expected association of risk with space-indicated by faster left-hand responses to low-risk stimuli and faster right-hand responses to high-risk stimuli. Risks appear to fit onto a standard left-right spatial association however, the effect sizes for all analyses were small. The results of this study are not only in line with the idea of a generalised magnitude processing system, but might also inform best practices in effective communications of risks.
Publisher: Elsevier BV
Date: 2022
DOI: 10.1016/J.NEUBIOREV.2021.11.046
Abstract: Delirium is a common neurocognitive disorder in hospitalised older adults with substantial negative consequences. Impaired global cognition is a well-established delirium risk factor. However, poor performance on attention tests and higher intra-subject variability may be more sensitive delirium risk factors, given the disorder is characterised by a fluctuating course and attentional deficits. We systematically searched databases (Embase, PsycINFO, MEDLINE) and 44 studies satisfied inclusion criteria. Random-effects meta-analysis models showed poor performance in all cognitive domains except perception was significantly associated with incident delirium. Largest effects were for orientation (g=-1.20) and construction and motor performance (g=-0.60). These effects were no longer significant in the subgroup without pre-existing cognitive impairment, where executive functions and verbal functions and language skills were associated with incident delirium. A small, non-significant association between intra-subject variability and incident delirium was found (g=0.42). Cognitive domain specific tests may be quicker and more sensitive predictors of incident delirium. This pattern of neuropsychological findings supports the proposition that vulnerability for delirium manifests as a dysfunction of whole-brain information integration.
Publisher: JMIR Publications Inc.
Date: 12-04-2021
Abstract: pathy is a frequent and underrecognized neurological disorder symptom. Reduced goal-directed behavior caused by apathy is associated with poor outcomes for older adults in residential aged care. Recommended nonpharmacological treatments include person-centered therapy using information and communication technology. Virtual reality (VR) in the form of head-mounted displays (HMDs) is a fully immersive technology that provides access to a wide range of freely available content. The use of VR as a therapy tool has demonstrated promise in the treatment of posttraumatic stress disorder and anxiety. In addition, VR has been used to improve conditions including depression, anxiety, cognitive function, and balance in older adults with memory deficits, Alzheimer disease, and Parkinson disease. Research using VR for the symptoms of apathy in older adults living in residential aged care facilities is limited. his study aims to examine whether using HMDs as a tool for reminiscence therapy improves the symptoms of apathy compared with using a laptop computer and physical items with older adults living in residential aged care. n this multisite trial, 43 participants were allocated to one of three groups: reminiscence therapy intervention using VR in the form of HMDs, reminiscence therapy using a laptop computer supplemented by physical items if required (active control), and a usual care (passive control) group. The primary outcome was apathy, and the secondary outcomes included cognition and depression. The side effects of using HMDs were also measured in the VR group. ixed model analyses revealed no significant group interaction over time in outcomes between the VR and laptop groups (estimate=−2.24, SE 1.89 i t /i sub /sub =−1.18 i P= /i .24). Pooled apathy scores in the two intervention groups compared with the passive control group also revealed no significant group interaction over time (estimate=−0.26, SE 1.66 i t /i sub /sub =−0.16 i P= /i .88). There were no significant secondary outcomes. Most participants in the VR group stated that they would prefer to watch content in VR than on a flat screen ( i Χ /i sup /sup sub /sub =11.2 i P /i =.004), side effects from HMD use were negligible to minimal according to the Simulator Sickness Questionnaire cutoff scores. lthough there were no significant results in outcome measures, this study found that participants engaged in the research and enjoyed the process of reminiscing using both forms of technology. It was found that VR can be implemented in an aged care setting with correct protocols in place. Providing residents in aged care with a choice of technology may assist in increasing participation in activities. We cannot dismiss the importance of immediate effects while the therapy was in progress, and this is an avenue for future research. ustralian New Zealand Clinical Trials Registry ACTRN12619001510134 www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378564. R2-DOI: 10.1136/bmjopen-2020-046030
Publisher: Emerald
Date: 18-11-2013
Abstract: – This paper describes the development of a novel integrative self-directed treatment tool which uses cognitive behavioural therapy techniques to reduce anxiety symptoms in patients presenting to treatment for alcohol-related problems. More specifically, the purpose of this paper is to explore patient and health practitioner perceptions of the booklet, in order to determine its suitability and utility in the context of existing alcohol treatment services. The extent of cross-informant agreement between patient and health practitioner responses is also examined. – This research utilises a cross-sectional qualitative research design using semi-structured interview methods with patients presenting to hospital for alcohol-related diseases/illnesses/accidents/injuries ( n =15) and practitioners ( n =10) working at inpatient, outpatient and residential substance treatment facilities. – The present study found that the majority of patients (80 per cent) and practitioners (90 per cent) expressed a motivation to utilise the proposed booklet, agreeing that the booklet was a practical, achievable and educational resource for patients suffering from co-occurring anxiety symptoms in substance abuse facilities. Participants outlined limitations of the resource, suggesting that the booklet would be most suitable for patients with moderate to high cognitive ability, who also exhibit a motivation to change alcohol consumption and have access to additional support. – Findings from the present study suggest that the booklet may be most effective in improving treatment accessibility and patient treatment seeking behaviours rather than reducing practitioner-patient contact. – This paper focuses on the development and utility of a novel resource suitable for substance abuse treatment facilities. The findings and feedback produced from the present study can assist with modifications of the intervention and in improving the effectiveness of future trials.
Publisher: Wiley
Date: 29-12-2010
DOI: 10.1002/GPS.2572
Abstract: The aim of the study was to conduct a meta-analysis of epidemiological and case control studies to determine whether arterial hypertension is specifically associated with an increased risk of vascular dementia (VaD). Longitudinal and cross-sectional prospective studies using operationalised criteria to define VaD and hypertension, with a normal control comparison group were systematically reviewed. Cochrane Library, Embase, Medline, and PsycInfo data sources were searched along with reference lists of included articles and reviews. Original, prevalence or incidence studies were included if operationalised criteria for hypertension and VaD as well as number of cases with and without hypertension in VaD and non-demented groups were provided. Intervention studies and post-stroke and CADASIL studies were excluded. Eleven studies recruiting either volunteers or clinical patients, or which were population-based, examined a total of 768 people with VaD and 9857 control cases. A meta-analysis of the six longitudinal studies showed that hypertension was significantly associated with increased risk of incident VaD (odds ratio, OR: 1.59, CI: 1.29-1.95, p < 0.0001). A similar association between hypertension and the risk of prevalent VaD was found in the five cross-sectional studies (OR: 4.84, CI: 3.52-6.67, p < 0.00001). Hypertension significantly increases the risk of vascular dementia. The current meta-analysis highlights the potential importance of rigorous treatment of hypertension as a key measure to help prevent the development of VaD.
Publisher: Oxford University Press (OUP)
Date: 09-08-2012
DOI: 10.1093/BRAIN/AWS190
Publisher: Frontiers Media SA
Date: 03-07-2020
Publisher: Springer Science and Business Media LLC
Date: 11-08-2017
Publisher: Frontiers Media SA
Date: 31-03-2020
Publisher: Elsevier BV
Date: 08-2019
Publisher: Oxford University Press (OUP)
Date: 06-2023
Abstract: Implantable cardioverter defibrillators (ICDs) prevent sudden cardiac death. Anxiety, depression, and post-traumatic stress disorder (PTSD) are underappreciated symptoms. We aimed to systematically synthesize prevalence estimates of mood disorders and symptom severities, pre- and post-ICD insertions. Comparisons were made with control groups, as well as within ICD patients by indication (primary vs. secondary), sex, shock status, and over time. Databases (Medline, PsycINFO, PubMed, and Embase) were searched without limits from inception to 31 August 2022 4661 articles were identified, 109 (39 954 patients) of which met criteria. Random-effects meta-analyses revealed clinically relevant anxiety in 22.58% (95%CI 18.26–26.91%) of ICD patients across all timepoints following insertion and depression in 15.42% (95%CI 11.90–18.94%). Post-traumatic stress disorder was seen in 12.43% (95%CI 6.90–17.96%). Rates did not vary relative to indication group. Clinically relevant anxiety and depression were more likely in ICD patients who experienced shocks [anxiety odds ratio (OR) = 3.92 (95%CI 1.67–9.19) depression OR = 1.87 (95%CI 1.34–2.59)]. Higher symptoms of anxiety were seen in females than males post-insertion [Hedges’ g = 0.39 (95%CI 0.15–0.62)]. Depression symptoms decreased in the first 5 months post-insertion [Hedges’ g = 0.13 (95%CI 0.03–0.23)] and anxiety symptoms after 6 months [Hedges’ g = 0.07 (95%CI 0–0.14)]. Depression and anxiety are highly prevalent in ICD patients, especially in those who experience shocks. Of particular concern is the prevalence of PTSD following ICD implantation. Psychological assessment, monitoring, and therapy should be offered to ICD patients and their partners as part of routine care.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2009
DOI: 10.1161/STROKEAHA.109.559880
Abstract: Background and Purpose— Stroke is implicated in the incidence of dementia, and the risk of poststroke dementia is well characterized, but the excess risk of dementia in those with stroke compared with those without stroke is not well known. Methods— We conducted a systematic review of the excess risk of incident dementia conferred by stroke. Studies of the risk of incident dementia in the population with stroke compared with the population without stroke were identified and compared. Results— Sixteen studies were identified with all but one conducted in a community setting. A history of stroke doubles the risk of incident dementia in the older population. This increase is not explained by demographic or cardiovascular risk factors or by prestroke cognitive decline. The excess risk of incident dementia diminishes with time after stroke and may be higher in those without an APOE ε4 allele. There is no excess risk of incident dementia in those aged years with a history of stroke compared to those aged years without stroke. Conclusions— The effect of stroke on dementia incidence in the population is not explained by common risk factors. At this time of population aging and increased stroke survival, more research is needed to determine to what extent efforts to reduce the incidence of stroke will affect the incidence of dementia.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.NEUROSCIENCE.2019.08.038
Abstract: Brain connectivity studies have reported that functional networks change with older age. We aim to (1) investigate whether electroencephalography (EEG) data can be used to distinguish between in idual functional networks of young and old adults and (2) identify the functional connections that contribute to this classification. Two eyes-open resting-state EEG recording sessions with 64 electrodes for each of 22 younger adults (19-37 years) and 22 older adults (63-85 years) were conducted. For each session, imaginary coherence matrices in delta, theta, alpha, beta and gamma bands were computed. A range of machine learning classification methods were utilized to distinguish younger and older adult brains. A support vector machine (SVM) classifier was 93% accurate in classifying the brains by age group. We report decreased functional connectivity with older age in delta, theta, alpha and gamma bands, and increased connectivity with older age in beta band. Most connections involving frontal, temporal, and parietal electrodes, and more than half of connections involving occipital electrodes, showed decreased connectivity with older age. Slightly less than half of the connections involving central electrodes showed increased connectivity with older age. Functional connections showing decreased strength with older age were not significantly different in electrode-to-electrode distance than those that increased with older age. Most of the connections used by the classifier to distinguish participants by age group belonged to the alpha band. Findings suggest a decrease in connectivity in key networks and frequency bands associated with attention and awareness, and an increase in connectivity of the sensorimotor functional networks with aging during a resting state.
Publisher: Cold Spring Harbor Laboratory
Date: 13-12-2018
DOI: 10.1101/495564
Abstract: Brain connectivity studies have reported that functional networks change with older age. We aim to (1) investigate whether electroencephalography (EEG) data can be used to distinguish between in idual functional networks of young and old adults and (2) identify the functional connections that contribute to this classification. Two eyes-open resting-state EEG recording sessions with 64 electrodes for each of 22 younger adults (19-37 years) and 22 older adults (63-85 years) were conducted. For each session, imaginary coherence matrices in theta, alpha, beta and gamma bands were computed. A range of machine learning classification methods were utilized to distinguish younger and older adult brains. A support vector machine (SVM) classifier was 94% accurate in classifying the brains by age group. We report decreased functional connectivity with older age in theta, alpha and gamma bands, and increased connectivity with older age in beta band. Most connections involving frontal, temporal, and parietal electrodes, and approximately two-thirds of connections involving occipital electrodes, showed decreased connectivity with older age. Just over half of the connections involving central electrodes showed increased connectivity with older age. Functional connections showing decreased strength with older age had significantly longer electrode-to-electrode distance than those that increased with older age. Most of the connections used by the classifier to distinguish participants by age group belonged to the alpha band. Findings suggest a decrease in connectivity in key networks and frequency bands associated with attention and awareness, and an increase in connectivity of the sensorimotor functional networks with ageing during a resting state.
Publisher: MDPI AG
Date: 16-02-2017
DOI: 10.3390/NU9020145
Publisher: Wiley
Date: 20-09-2017
DOI: 10.1111/NAN.12430
Publisher: Cold Spring Harbor Laboratory
Date: 03-07-2018
DOI: 10.1101/361170
Abstract: Repeated exposure to a stimulus leads to reduced responses of stimulus-selective sensory neurons, an effect known as repetition suppression or stimulus-specific adaptation. Several influential models have been proposed to explain repetition suppression within hierarchically-organised sensory systems, with each specifying different mechanisms underlying repetition effects. We manipulated temporal expectations within a face repetition experiment to test a critical prediction of the predictive coding model of repetition suppression: that repetition effects will be larger following stimuli that appear at expected times compared to stimuli that appear at unexpected times. We recorded event-related potentials from 18 participants and mapped the spatiotemporal progression of repetition effects using mass univariate analyses. We then assessed whether the magnitudes of observed face image repetition effects were influenced by temporal expectations. In each trial participants saw an adapter face, followed by a 500ms or 1000ms interstimulus interval (ISI), and then a test face, which was the same or a different face identity to the adapter. Participants’ expectations for whether the test face would appear after a 500ms ISI were cued by the sex of the adapter face. Our analyses revealed multiple repetition effects with distinct scalp topographies, extending until at least 800ms from stimulus onset. An early (158-203ms) repetition effect was larger for stimuli following surprising, rather than expected, 500ms ISI durations, contrary to the model predictions of the predictive coding model of repetition suppression. Later (230-609ms) repetition effects tended to be larger following expected stimulus onset times, in line with predictive coding models. Our results indicate that the relationship between repetition suppression and temporal expectation differs across the time course of the stimulus-evoked response, suggesting multiple distinct mechanisms driving repetition suppression that operate at different latencies within the visual hierarchy. - Multiple face image repetition effects identified from 162-800ms post stimulus onset - Temporal expectations influenced the magnitudes of repetition effects - Temporal expectation effects differed for early and late stimulus-evoked responses
Publisher: Elsevier BV
Date: 2021
Publisher: MDPI AG
Date: 04-07-2019
DOI: 10.3390/NU11071521
Abstract: Abstract: Background: The Mediterranean diet may be capable of improving cognitive function. However, the red meat restrictions of the diet could impact long-term adherence in Western populations. The current study therefore examined the cognitive effects of a Mediterranean diet with additional red meat. Methods: A 24-week parallel crossover design compared a Mediterranean diet with 2–3 weekly servings of fresh, lean pork (MedPork) and a low-fat (LF) control diet. Thirty-five participants aged between 45 and 80 years and at risk of cardiovascular disease followed each intervention for 8 weeks, separated by an 8-week washout period. Cognitive function was assessed using the Cambridge Neuropsychological Test Automated Battery. Psychological well-being was measured through the SF-36 Health Survey and mood was measured using the Profile of Mood States (POMS). Results: During the MedPork intervention, participants consumed an average of 3 weekly servings of fresh pork. Compared to LF, the MedPork intervention led to higher processing speed performance (p = 0.01) and emotional role functioning (p = 0.03). No other significant differences were observed between diets. Conclusion: Our findings indicate that a Mediterranean diet inclusive of fresh, lean pork can be adhered to by an older non-Mediterranean population while leading to positive cognitive outcomes.
Publisher: Elsevier BV
Date: 10-2023
Publisher: BMJ
Date: 12-2021
DOI: 10.1136/BMJNO-2021-000199
Abstract: Delirium is a neurocognitive disorder common in older adults in acute care settings. Those who develop delirium are at an increased risk of dementia, cognitive decline and death. Electroencephalography (EEG) during delirium in older adults is characterised by slowing and reduced functional connectivity, but markers of vulnerability are poorly described. We aim to identify EEG spectral power and event-related potential (ERP) markers of incident delirium in older adults to understand neural mechanisms of delirium vulnerability. Characterising delirium vulnerability will provide substantial theoretical advances and outcomes have the potential to be translated into delirium risk assessment tools. We will record EEG in 90 participants over 65 years of age prior to elective coronary artery bypass grafting (CABG) or transcatheter aortic valve implantation (TAVI). We will record 4-minutes of resting state (eyes open and eyes closed) and a 5-minute frequency auditory oddball paradigm. Outcome measures will include frequency band power, 1/f offset and slope, and ERP litude measures. Participants will undergo cognitive and EEG testing before their elective procedures and daily postoperative delirium assessments. Group allocation will be done retrospectively by linking preoperative EEG data according to postoperative delirium status (presence, severity, duration and subtype). This study is approved by the Human Research Ethics Committee of the Royal Adelaide Hospital, Central Adelaide Local Health Network and the University of South Australia Human Ethics Committee. Findings will be disseminated through peer-reviewed journal articles and presentations at national and international conferences. ACTRN12618001114235 and ACTRN12618000799257.
Publisher: Springer Science and Business Media LLC
Date: 05-10-2017
Publisher: Oxford University Press (OUP)
Date: 09-2022
Abstract: Delirium is a common neurocognitive disorder in hospitalised older adults with vast negative consequences. The predominant method of subtyping delirium is by motor activity profile into hypoactive, hyperactive and mixed groups. This systematic review and meta-analysis investigated how predisposing factors differ between delirium motor subtypes. Databases (Medline, PsycINFO, Embase) were systematically searched for studies reporting predisposing factors (prior to delirium) for delirium motor subtypes. A total of 61 studies met inclusion criteria (N = 14,407, mean age 73.63 years). Random-effects meta-analyses synthesised differences between delirium motor subtypes relative to 22 factors. Hypoactive cases were older, had poorer cognition and higher physical risk scores than hyperactive cases and were more likely to be women, living in care homes, taking more medications, with worse functional performance and history of cerebrovascular disease than all remaining subtypes. Hyperactive cases were younger than hypoactive and mixed subtypes and were more likely to be men, with better cognition and lower physical risk scores than all other subtypes. Those with no motor subtype (unable to be classified) were more likely to be women and have better functional performance. Effect sizes were small. Important differences in those who develop motor subtypes of delirium were shown prior to delirium occurrence. We provide robust quantitative evidence for a common clinical assumption that indices of frailty (institutional living, cognitive and functional impairment) are seen more in hypoactive patients. Motor subtypes should be measured across delirium research. Motor subtyping has great potential to improve the clinical risk assessment and management of delirium.
Publisher: Informa UK Limited
Date: 25-09-2017
DOI: 10.1080/23279095.2017.1363039
Abstract: This review aimed to systematically evaluate associations between the Metabolic Syndrome and domain specific cognitive performance from cross-sectional studies. PsycINFO and Medline were searched on 12 January 2017 with the terms "Metabolic Syndrome" and "cogni*." A total of 973 articles were identified, with 26 meeting inclusion criteria. In iduals with Metabolic Syndrome were consistently reported to have poorer performance on executive function tasks that were not adaptations of the verbal fluency task, including the Stockings of Cambridge test, Color-Word Inference Test and Frontal Assessment Battery findings from adaptations of the verbal fluency test showed less consistent results. Associations with performance in attention/working memory/information processing, memory, language, and construction/motor performance domains were mixed. All studies reporting on perception showed nonsignificant results. Non-language based executive function tasks appear to be the most sensitive tests of Metabolic Syndrome, and hold promise as a cognitive screen and for the tracking of interventions in this group.
Publisher: Informa UK Limited
Date: 03-2016
DOI: 10.1111/AJPY.12083
Publisher: Public Library of Science (PLoS)
Date: 17-07-2012
Publisher: Springer Science and Business Media LLC
Date: 23-08-2019
DOI: 10.1007/S00221-019-05632-W
Abstract: Risk perception has recently been shown to reveal a mental spatial representation, with people responding faster to low-risk items on the left side, and high-risk items on the right side. Subjective risk perception has a stronger spatial representation than objective risk perception however, both reveal small effect sizes. With risk magnitude being a new domain within spatial mapping literature, we sought to explore its nuances. Following discussion surrounding the relationship between spatial mapping and level of expertise, this study investigated the effect of training an objective risk magnitude sequence on mental spatial representations. Participants (n = 34) used their left and right hands to indicate whether eight risk stimuli were lower or higher risk than a referent activity, both before and after training. Training involved repetitively learning the objectively correct order of the same eight risk stimuli for approximately 15 min. Pre-training results demonstrated the expected spatial representations. Contrary to our predictions, the spatial representation did not get stronger post-training, but instead disappeared. Previous research has demonstrated a loss of spatial-numerical mappings with increased task load. An increase in post-training reaction times could reflect an increase in task load due to a lack of adequate knowledge of risk stimulus order thus revealing no mental spatial representation. However, failure to find training effects highlights the flexibility of weaker spatial representations, and supports research demonstrating spatial representation flexibility.
Publisher: American Psychological Association (APA)
Date: 09-2015
DOI: 10.1037/PAG0000026
Abstract: The brain is dependent on the cerebrovascular system, particularly microvasculature, for a consistent blood supply however, age-related changes in this system affect neuronal and therefore cognitive function. Structural vascular markers and vascular disease appear to preferentially affect fluid cognitive abilities, sparing crystallized abilities. We sought to investigate the relationships between cerebrovascular function and cognitive domains. Fifty in iduals between 60 and 75 years of age (31 women, 19 men) underwent cognitive testing: Wechsler Vocabulary and Matrix Reasoning subtests (crystallized and fluid ability measures, respectively Wechsler, 2011), and the Addenbrooke's Cognitive Examination-Revised (ACE-R general cognitive ability Mioshi, Dawson, Mitchell, Arnold, & Hodges, 2006). Transcranial Doppler (TCD) measures were also collected at rest and during a cognitive word-generation task, from which a lateralization index was calculated. Lower pulsatility index at rest, and greater left lateralization during the TCD cognitive task were associated with better performance on the Matrix Reasoning but not the Vocabulary test these effects were independent from each other and from any vascular comorbidity burden. These functional findings confirm previous structural studies, which revealed that fluid abilities are more vulnerable to cerebrovascular dysfunction than crystallized abilities, and identify two (likely related) mechanisms: degraded cerebrovascular integrity (indexed by pulsatility index) and a delateralization of function. Cerebrovascular dysfunction is a key contributor to cognitive aging that deserves further attention, particularly in relation to early diagnostic markers of impairment and monitoring of vascular (e.g., physical activity) interventions.
Publisher: Informa UK Limited
Date: 08-11-2018
Publisher: Informa UK Limited
Date: 13-08-2017
Publisher: Springer Science and Business Media LLC
Date: 30-01-2018
Publisher: Frontiers Media SA
Date: 09-06-2023
Publisher: Springer Science and Business Media LLC
Date: 12-05-2021
DOI: 10.1038/S41598-021-89054-1
Abstract: Current evidence suggests that the ability to detect and react to information under lowered alertness conditions might be more impaired on the left than the right side of space. This evidence derives mainly from right-handers being assessed in computer and paper-and-pencil spatial attention tasks. However, there are suggestions that left-handers might show impairments on the opposite (right) side compared to right-handers with lowered alertness, and it is unclear whether the impairments observed in the computer tasks have any real-world implications for activities such as driving. The current study investigated the alertness and spatial attention relationship under simulated monotonous driving in left- and right-handers. Twenty left-handed and 22 right-handed participants (15 males, mean age = 23.6 years, SD = 5.0 years) were assessed on a simulated driving task (lasting approximately 60 min) to induce a time-on-task effect. The driving task involved responding to stimuli appearing at six different horizontal locations on the screen, whilst driving in a 50 km/h zone. Decreases in alertness and driving performance were evident with time-on-task in both handedness groups. We found handedness impacts reacting to lateral stimuli differently with time-on-task: right-handers reacted slower to the leftmost stimuli, while left-handers showed the opposite pattern (although not statistically significant) in the second compared to first half of the drive. Our findings support suggestions that handedness modulates the spatial attention and alertness interactions. The interactions were observed in a simulated driving task which calls for further research to understand the safety implications of these interactions for activities such as driving.
Publisher: BMJ
Date: 02-2020
DOI: 10.1136/BMJOPEN-2019-034551
Abstract: Coronary artery bypass grafting (CABG) surgery is known to improve vascular function and cardiac-related mortality rates however, it is associated with high rates of postoperative cognitive decline and delirium. Previous attempts to prevent post-CABG cognitive decline using pharmacological and surgical approaches have been largely unsuccessful. Cognitive prehabilitation and rehabilitation are a viable yet untested option for CABG patients. We aim to investigate the effects of preoperative cognitive training on delirium incidence, and preoperative and postoperative cognitive training on cognitive decline at 4 months post-CABG. This study is a randomised, single-blinded, controlled trial investigating the use of computerised cognitive training (CCT) both pre-CABG and post-CABG (intervention group) compared with usual care (control group) in older adults undergoing CABG in Adelaide, South Australia. Those in the intervention group will complete 1–2 weeks of CCT preoperatively (45–60 min sessions, 3.5 sessions/week) and 12 weeks of CCT postoperatively (commencing 1 month following surgery, 45–60 min sessions, 3 sessions/week). All participants will undergo cognitive testing preoperatively, over their hospital stay including delirium, and postoperatively for up to 1 year. The primary delirium outcome variable will be delirium incidence (presence vs absence) the primary cognitive decline variable will be at 4 months (significant decline vs no significant decline/improvement from baseline). Logistic regression modelling will be used, with age and gender as covariates. Secondary outcomes include cognitive decline from baseline to discharge, and at 6 months and 1 year post-CABG. Ethics approval was obtained from the Central Adelaide Local Health Network Human Research Ethics Committee (South Australia, Australia) and the University of South Australia Human Ethics Committee, with original approval obtained on 13 December 2017. It is anticipated that approximately two to four publications and multiple conference presentations (national and international) will result from this research. This clinical trial is registered with the Australian New Zealand Clinical Trials Registry and relates to the pre-results stage. Registration number: ACTRN12618000799257.
Publisher: Informa UK Limited
Date: 06-03-2022
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2006
DOI: 10.1142/S0219635206001070
Abstract: The current study aimed to investigate whether children and adolescents diagnosed with Attention Deficit/Hyperactivity Disorder Predominantly Inattentive (AD/HD-in Child n = 24, Adolescent n = 33) and Combined (AD/HD-com Child n = 30, Adolescent n = 42) subtypes were more distractible than controls (Child n = 54 Adolescents n = 75), by assessing event-related potential (ERP), performance and peripheral arousal measures. All AD/HD groups displayed smaller litudes and/or shorter latencies of the P3a ERP component - thought to reflect involuntary attention switching - following task-deviant novel stimuli (checkerboard patterns) embedded in a Working Memory (WM) task. The P3a results suggested that both AD/HD-in and AD/HD-com subtypes ineffectively evaluate deviant stimuli and are hence more "distractible". These abnormalities were most pronounced over the central areas. AD/HD groups did not display any abnormalities in averaged heart rate over the WM task, a measure of peripheral arousal. They did display abnormalities in performance measures from the task, but these were unrelated to P3a abnormalities. AD/HD groups also displayed a number of deficits on Switching of Attention and Verbal Memory tasks, however, the pattern of abnormality mostly reflected general cognitive deficits rather than resulting from distraction.
Publisher: Springer Science and Business Media LLC
Date: 08-01-2021
DOI: 10.1038/S41598-020-80211-6
Abstract: Cognitive side effects of anticholinergic medications in older adults are well documented. Whether these poor cognitive outcomes are observed in children has not been systematically investigated. We aimed to conduct a systematic review and meta-analysis on the associations between anticholinergic medication use and cognitive performance in children. Systematic review was conducted using Medline, PsychInfo, and Embase, identifying studies testing cognitive performance relative to the presence versus absence of anticholinergic medication(s) in children. We assessed effects overall, as well as relative to drug class, potency (low and high), cognitive domain, and duration of administration. The systematic search identified 46 articles suitable for meta-analysis. For the most part, random effects meta-analyses did not identify statistically significant associations between anticholinergic exposure and cognitive performance in children the one exception was a small effect of anticholinergic anti-depressants being associated with better cognitive function (Hedges’ g = 0.24, 95% CI 0.06–0.42, p = 0.01). Anticholinergic medications do not appear to be associated with poor cognitive outcomes in children, as they do in older adults. The discrepancy in findings with older adults may be due to shorter durations of exposure in children, differences in study design (predominantly experimental studies in children rather than predominantly epidemiological in older adults), biological ageing (e.g. blood brain barrier integrity), along with less residual confounding due to minimal polypharmacy and comorbidity in children.
Publisher: Elsevier BV
Date: 03-2023
Publisher: Springer Science and Business Media LLC
Date: 26-12-2018
DOI: 10.1007/S00221-017-5154-6
Abstract: The spatial numerical association of response code (SNARC) effect is characterized by low numbers mapped to the left side of space and high numbers mapped to the right side of space. In addition to numbers, SNARC-like effects have been found in non-numerical magnitude domains such as time, size, letters, luminance, and more, whereby the smaller/earlier and larger/later magnitudes are typically mapped to the left and right of space, respectively. The purpose of this systematic and meta-analytic review was to identify and summarise all empirical papers that have investigated horizontal (left-right) SNARC-like mappings using non-numerical stimuli. A systematic search was conducted using EMBASE, Medline, and PsycINFO, where 2216 publications were identified, with 57 papers meeting the inclusion criteria (representing 112 experiments). Ninety-five of these experiments were included in a meta-analysis, resulting in an overall effect size of d = .488 for a SNARC-like effect. Additional analyses revealed a significant effect size advantage for explicit instruction tasks compared with implicit instructions, yet yielded no difference for the role of expertise on SNARC-like effects. There was clear evidence for a publication bias in the field, but the impact of this bias is likely to be modest, and it is unlikely that the SNARC-like effect is a pure artefact of this bias. The similarities in the response properties for the spatial mappings of numerical and non-numerical domains support the concept of a general higher order magnitude system. Yet, further research will need to be conducted to identify all the factors modulating the strength of the spatial associations.
Publisher: European Delirium Association
Date: 21-02-2023
DOI: 10.56392/001C.67976
Abstract: Cognitive impairments, including delirium, are common after coronary artery bypass grafting (CABG). Improving cognition pre- and post-operatively using computerised cognitive training (CCT) may be an effective approach to improve cognitive outcomes in CABG patients. Investigate the effect of remotely supervised CCT on cognitive outcomes, including delirium, in older adults undergoing CABG surgery. Thirty-six participants, were analysed in a single-blinded randomised controlled trial (CCT Intervention: n = 18, Control: n = 18). CCT was completed by the intervention group pre-operatively (every other day, 45–60-minute sessions until surgery) and post-operatively, beginning 1-month post-CABG (3 x 45–60-minute sessions/week for 12-weeks), while the control group maintained usual care plus weekly phone calls. Cognitive assessments were conducted pre- and post-operatively at multiple follow-ups (discharge, 4-months and 6-months). Post-operative delirium incidence was assessed daily until discharge. Cognitive change data were calculated at each follow-up for each cognitive test (Addenbrooke’s Cognitive Examination III and CANTAB z-scored). Adherence to the CCT intervention (completion of three pre-operative or 66% of post-operative sessions) was achieved in 68% of pre-CABG and 59% of post-CABG participants. There were no statistically significant effects of CCT on any cognitive outcome, including delirium incidence. Adherence to the CCT program was comparatively higher than previous feasibility studies, possibly due to the level of supervision and support provided (blend of face-to-face and home-based training, with support phone calls). Implementing CCT interventions both pre- and post-operatively is feasible in those undergoing CABG. No statistically significant benefits from the CCT interventions were identified for delirium or cognitive function post-CABG, likely due to the s le size available (study recruitment greatly impacted by COVID-19). It also may be the case that multimodal intervention would be more effective.
Publisher: Informa UK Limited
Date: 02-09-2020
Publisher: BMJ
Date: 02-2021
DOI: 10.1136/BMJOPEN-2020-046030
Abstract: Apathy is a prevalent neuropsychiatric symptom for older adults residing in aged care. Left untreated, apathy has been associated with accelerated cognitive decline and increased risk of mortality. Reminiscence therapy is commonly used in aged care and has demonstrated to reduce apathy. Traditional methods of reminiscence use physical objects and more recently technology including tablets and laptop computers have demonstrated potential. Virtual reality (VR) has successfully been used to treat psychological disorders however, there is little evidence on using VR for behavioural symptoms such as apathy in older adults. Using VR to deliver reminiscence therapy provides an immersive experience, and readily available applications provide access to a large range of content allowing easier delivery of therapy over traditional forms of therapy. This study aims to identify changes in apathy after a reminiscence therapy intervention using head-mounted displays (HMDs). Participants will be allocated to one of three groups reminiscence therapy using VR an active control using a laptop computer or physical items and a passive control. A total of 45 participants will be recruited from residential aged care (15 in each group). The three groups will be compared at baseline and follow-up. The primary outcome is apathy, and secondary outcomes include cognition and depression. Side effects from using HMDs will also be examined in the VR group. Primary and secondary outcomes at baseline and follow-up will be analysed using linear mixed modelling. Ethics approval was obtained from the University of South Australia Human Research Ethics Committee. The results from this study will be disseminated through manuscript publications and national/international conferences. ACTRN12619001510134.
Publisher: Frontiers Media SA
Date: 30-07-2019
Publisher: Cold Spring Harbor Laboratory
Date: 03-05-2019
DOI: 10.1101/625608
Abstract: Cognitive reserve is a concept that explains in idual differences in vulnerability to cognitive impairment due to age and dementia-related brain changes. Mechanisms underlying the cognitive reserve effect are poorly understood. We investigated associations between a comprehensive cognitive reserve proxy (Lifetime Experiences Questionnaire/LEQ) and functional connectivity of the prefrontal cortex across the whole scalp, covarying for the level of current cognitive functioning (Addenbrookes Cognitive Examination Revised/ACE-R), using multiblock parallel and orthogonalized partial least squares regression. EEG data were collected from 34 healthy older adults (63 to 83 years) in eyes-open and eyes-closed resting-states, and during 0-back and 1-back tasks. Functional connectivity was estimated using imaginary coherence in the theta and alpha frequency bands, as these bands have been heavily implicated in cognitive ageing, attention and executive function. We found three clusters of electrodes where the absolute values of the regression coefficient were above threshold when covarying for ACE-R: (1) a cluster approximating the right frontocentral region during the eyes-open condition in the theta band with seed electrodes approximating the left prefrontal cortex with positive associations of medium effect size (2) a cluster approximating the right parietotemporal region during the 0-back task in the theta band with seed electrodes approximating the right prefrontal cortex with negative associations of medium to large effect sizes and (3) a cluster approximating the occipitoparietal region in the eyes-closed condition in the alpha band with seed electrodes approximating the left prefrontal cortex with negative associations of medium effect size. These relationships between a cognitive reserve proxy and functional connectivity, within key networks and frequency bands associated with attention and executive function, may reflect greater neural capacity and efficiency.
Publisher: Elsevier BV
Date: 09-2021
Publisher: BMJ
Date: 2022
DOI: 10.1136/BMJOPEN-2020-047888
Abstract: Approximately 40% of late-life dementia may be prevented by addressing modifiable risk factors, including physical activity and diet. Yet, it is currently unknown how multiple lifestyle factors interact to influence cognition. The ACTIVate Study aims to (1) explore associations between 24-hour time-use and diet compositions with changes in cognition and brain function and (2) identify duration of time-use behaviours and the dietary compositions to optimise cognition and brain function. This 3-year prospective longitudinal cohort study will recruit 448 adults aged 60–70 years across Adelaide and Newcastle, Australia. Time-use data will be collected through wrist-worn activity monitors and the Multimedia Activity Recall for Children and Adults. Dietary intake will be assessed using the Australian Eating Survey food frequency questionnaire. The primary outcome will be cognitive function, assessed using the Addenbrooke’s Cognitive Examination-III. Secondary outcomes include structural and functional brain measures using MRI, cerebral arterial pulse measured with diffuse optical tomography, neuroplasticity using simultaneous transcranial magnetic stimulation and electroencephalography, and electrophysiological markers of cognitive control using event-related potential and time frequency analyses. Compositional data analysis, testing for interactions between time point and compositions, will assess longitudinal associations between dependent (cognition, brain function) and independent (time-use and diet compositions) variables. The ACTIVate Study will be the first to examine associations between time-use and diet compositions, cognition and brain function. Our findings will inform new avenues for multidomain interventions that may more effectively account for the co-dependence between activity and diet behaviours for dementia prevention. Ethics approval has been obtained from the University of South Australia’s Human Research Ethics committee (202639). Findings will be disseminated through peer-reviewed manuscripts, conference presentations, targeted media releases and community engagement events. Australia New Zealand Clinical Trials Registry (ACTRN12619001659190).
Publisher: Frontiers Media SA
Date: 19-06-2018
Publisher: Cold Spring Harbor Laboratory
Date: 05-2017
DOI: 10.1101/132621
Abstract: Repeated stimulus presentation leads to complex changes in cortical neuron response properties, commonly known as repetition suppression or stimulus-specific adaptation. Circuit-based models of repetition suppression provide a framework for investigating patterns of repetition effects that propagate through cortical hierarchies. To further develop such models it is critical to determine whether (and if so, when) repetition effects are modulated by top-down influences, such as those related to perceptual expectation. We investigated this by presenting pairs of repeated and alternating face images, and orthogonally manipulating expectations regarding the likelihood of stimulus repetition. Event-related potentials (ERPs) were recorded from n=39 healthy adults, to map the spatiotemporal progression of stimulus repetition and expectation effects, and interactions between these factors, using mass univariate analyses. We also tested whether the ability to predict unrepeated (compared to repeated) face identities could influence the magnitude of observed repetition effects, by presenting separate blocks with predictable and unpredictable alternating faces. Multiple repetition and expectation effects were identified between 99-800ms from stimulus onset, which did not statistically interact at any point. Repetition effects in blocks with predictable alternating faces were smaller than in unpredictable alternating face blocks between 117-179ms and 506-652ms, and larger between 246-428ms. ERP repetition effects appear not to be modulated by perceptual expectations, supporting separate mechanisms for repetition and expectation suppression. However, previous studies that aimed to test for repetition effects, in which the repeated (but not unrepeated) stimulus was predictable, are likely to have conflated repetition and stimulus predictability effects. - ERP face image repetition effects were apparent between 99-800ms from stimulus onset - Expectations of stimulus image properties did not modulate face repetition effects - The predictability of unrepeated stimuli influenced repetition effect magnitudes
Publisher: Springer Science and Business Media LLC
Date: 06-06-2020
Publisher: Center for Open Science
Date: 24-09-2020
Abstract: Background: Apathy is a prevalent neuropsychiatric symptom for older adults residing in aged care. Left untreated, apathy has been associated with accelerated cognitive decline and increased risk of mortality. Pharmacological interventions have not been established and can have side effects, placing a priority on the evaluation of non-pharmacological interventions. Reminiscence therapy, a psychosocial, person-centred intervention is commonly used in aged care and has demonstrated to reduce apathy. Traditional methods of reminiscence utilise physical objects and more recently technology including tablets and laptop computers have demonstrated potential. Virtual reality (VR) has successfully been used to treat psychological disorders, however there is little evidence on using VR for behavioural symptoms such as apathy in older adults. Using VR to deliver reminiscence therapy provides an immersive experience, and readily available applications provide access to a large range of content allowing easier delivery of therapy over traditional forms of therapy. This study aims to examine the effect of tailored reminiscence therapy using VR on apathy.Methods: In this multi-site trial, participants will be allocated to one of three groups a reminiscence therapy intervention using VR an active control using a laptop computer or physical items and a passive control usual care group. A total of 45 participants will be recruited from residential aged care (15 in each group). The three groups will be compared at baseline and follow-up. The primary outcome is apathy, secondary outcomes include cognition and depression. Side effects from using head-mounted displays will also be examined in the VR group.Discussion: This study intends to establish if using VR reminiscence therapy improves levels of apathy compared to traditional reminiscence therapy or usual care. Results from this study will inform the therapeutic use of VR for older adults residing in aged care and provide knowledge for implementing VR into existing lifestyle activities in this context.Trial registration: This trial was registered in the Australian and New Zealand Clinical Trials Registry (ACTRN12619001510134). Registered 31 October 2018, www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378564& isReview=true
Publisher: European Delirium Association
Date: 12-05-2023
DOI: 10.56392/001C.74542
Abstract: Transcatheter aortic valve implantation (TAVI) has become the standard for treating severe symptomatic aortic stenosis in those with prohibitive surgical risk. Cognitive complications, including delirium and cognitive decline are common following TAVI, yet an understanding of pre-procedural factors associated with these outcomes is lacking. This prospective observational study set out to identify geriatric pre-procedural factors associated with post-procedural delirium and cognitive decline in patients undergoing TAVI. Cognitive outcomes of TAVI patients aged ≥60 years (N=32) were measured over one-year post-TAVI. Pre-procedural measures included frailty, gait, visual symptoms, voice pitch, dysphagia, blink rate, mood, and sleep. Primary outcomes were post-procedural delirium and cognitive decline. Delirium was present in 25% of patients over two days following TAVI and 26% experienced cognitive decline in the year post-TAVI. Daily physical activity was a protective factor against cognitive decline, and worse baseline visual memory was associated with delirium. While non-significant and with very large confidence intervals, moderate to large effect sizes were found for associations between slowed gait speed, pre-existing atrial fibrillation, and dysphagia for delirium, and slower gait speed, higher blink rate, pre-existing atrial fibrillation for cognitive decline. Though underpowered, measures of considerable effect size were identified (although non-significant and with large variability). In larger studies, these novel geriatric factors could further be explored for predicting cognitive complications following TAVI. Improvement of risk prediction for cognitive decline and delirium following TAVI could assist with early identification of those at risk, informing clinical decision-making and allowing for targeted intervention to reduce post-procedural incidence of these complications.
Publisher: Springer Science and Business Media LLC
Date: 06-03-2014
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.BANDC.2014.05.001
Abstract: We aimed to investigate the contributions of visual letter form and abstract letter identity to the time course of letter recognition, by manipulating the typeface (i.e. font) in which letters were presented. Twenty-six adult participants completed a modified one-back task, where letters where presented in easy-to-read typefaces ("fluent" letter stimuli) or difficult-to-read typefaces ("disfluent" letter stimuli). Task instructions necessitated that participant's focus on letter identity not visual letter form. Electroencephalography was collected and event-related potentials (ERPs) were calculated relative to letter stimuli. It was found that typeface affected both early-mid (N1 litude and P2-N2 litude and latency) and late processing (450-600ms), thereby including time points whereby it is theorised that abstract identity is extracted from visual letter form (that is, 300ms post-stimulus). Visual features of the letter therefore affect its processing well beyond the currently theorised point at which abstract information is extracted which could be explained by a feedback loop between abstract letter representations and lower-level visual form processing units, which is not included in current cognitive reading models.
Publisher: Cold Spring Harbor Laboratory
Date: 31-07-2021
DOI: 10.1101/2021.07.28.21261299
Abstract: Approximately 40% of late-life dementia may be prevented by addressing modifiable risk factors, including physical activity and diet. Yet, it is currently unknown how multiple lifestyle factors interact to influence cognition. The ACTIVate Study aims to 1) Explore associations between 24-hour time-use and diet compositions with changes in cognition and brain function and 2) Identify durations of time-use behaviours and the dietary compositions to optimise cognition and brain function. This three-year prospective longitudinal cohort study will recruit 448 adults aged 60-70 years across Adelaide and Newcastle, Australia. Time-use data will be collected through wrist-worn activity monitors and the Multimedia Activity Recall for Children and Adults (MARCA). Dietary intake will be assessed using the Australian Eating Survey food frequency questionnaire. The primary outcome will be cognitive function, assessed using the Addenbrooke’s Cognitive Examination-III (ACE-III). Secondary outcomes include structural and functional brain measures using Magnetic Resonance Imaging (MRI), cerebral arterial pulse measured with Diffuse Optical Tomography (Pulse-DOT), neuroplasticity using simultaneous Transcranial Magnetic Stimulation (TMS) and Electroencephalography (EEG), and electrophysiological markers of cognitive control using event-related potential (ERP) and time-frequency analyses. Compositional data analysis, testing for interactions between time-point and compositions, will assess longitudinal associations between dependent (cognition, brain function) and independent (time-use and diet compositions) variables. The ACTIVate Study will be the first to examine associations between time-use and diet compositions, cognition and brain function. Our findings will inform new avenues for multidomain interventions that may more effectively account for the co-dependence between activity and diet behaviours for dementia prevention. Ethics approval has been obtained from University of South Australia’s Human Research Ethics committee (202639). Findings will be disseminated through peer reviewed manuscripts, conference presentations, targeted media releases and community engagement events. Australia New Zealand Clinical Trials Registry (ACTRN12619001659190). The ACTIVate Study will collect comprehensive measures of lifestyle behaviours and dementia risk over time in 448 older adults aged 60-70 years. Using newly developed Compositional Data Analysis (CoDA) techniques we will examine the associations between time-use and diet compositions, cognition and brain function. Data will inform the development of a digital tool to help older adults obtain personalised information about how to reduce their risk of cognitive decline based on changes to time use and diet. Recruitment will be focussed on older adults to maximise the potential of making an impact on dementia prevention in the next 10 years. Findings may not be generalisable to younger adults.
Publisher: JMIR Publications Inc.
Date: 20-09-2021
DOI: 10.2196/29210
Abstract: Apathy is a frequent and underrecognized neurological disorder symptom. Reduced goal-directed behavior caused by apathy is associated with poor outcomes for older adults in residential aged care. Recommended nonpharmacological treatments include person-centered therapy using information and communication technology. Virtual reality (VR) in the form of head-mounted displays (HMDs) is a fully immersive technology that provides access to a wide range of freely available content. The use of VR as a therapy tool has demonstrated promise in the treatment of posttraumatic stress disorder and anxiety. In addition, VR has been used to improve conditions including depression, anxiety, cognitive function, and balance in older adults with memory deficits, Alzheimer disease, and Parkinson disease. Research using VR for the symptoms of apathy in older adults living in residential aged care facilities is limited. This study aims to examine whether using HMDs as a tool for reminiscence therapy improves the symptoms of apathy compared with using a laptop computer and physical items with older adults living in residential aged care. In this multisite trial, 43 participants were allocated to one of three groups: reminiscence therapy intervention using VR in the form of HMDs, reminiscence therapy using a laptop computer supplemented by physical items if required (active control), and a usual care (passive control) group. The primary outcome was apathy, and the secondary outcomes included cognition and depression. The side effects of using HMDs were also measured in the VR group. Mixed model analyses revealed no significant group interaction over time in outcomes between the VR and laptop groups (estimate=−2.24, SE 1.89 t40=−1.18 P=.24). Pooled apathy scores in the two intervention groups compared with the passive control group also revealed no significant group interaction over time (estimate=−0.26, SE 1.66 t40=−0.16 P=.88). There were no significant secondary outcomes. Most participants in the VR group stated that they would prefer to watch content in VR than on a flat screen (Χ22=11.2 P=.004), side effects from HMD use were negligible to minimal according to the Simulator Sickness Questionnaire cutoff scores. Although there were no significant results in outcome measures, this study found that participants engaged in the research and enjoyed the process of reminiscing using both forms of technology. It was found that VR can be implemented in an aged care setting with correct protocols in place. Providing residents in aged care with a choice of technology may assist in increasing participation in activities. We cannot dismiss the importance of immediate effects while the therapy was in progress, and this is an avenue for future research. Australian New Zealand Clinical Trials Registry ACTRN12619001510134 www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378564. RR2-DOI: 10.1136/bmjopen-2020-046030
Publisher: Springer Science and Business Media LLC
Date: 11-09-2011
DOI: 10.1038/NPHYS2083
Publisher: JMIR Publications Inc.
Date: 26-06-2020
DOI: 10.2196/17632
Abstract: Apathy is a common symptom in neurological disorders, including dementia, and is associated with a faster rate of cognitive decline, reduced quality of life, and high caregiver burden. There is a lack of effective pharmacological treatments for apathy, and nonpharmacological interventions are a preferred first-line approach to treatment. Virtual reality (VR) using head-mounted displays (HMDs) is being successfully used in exposure- and distraction-based therapies however, there is limited research on using HMDs for symptoms of neurological disorders. This feasibility study aimed to assess whether VR using HMDs could be used to deliver tailored reminiscence therapy and examine the willingness to participate, response rates to measures, time taken to create tailored content, and technical problems. In addition, this study aimed to explore the immediate effects between verbal fluency and apathy after exposure to VR. A mixed methods study was conducted in a s le of older adults residing in aged care, and 17 participants were recruited. Apathy was measured using the Apathy Evaluation Scale (AES), and verbal fluency was used as a proxy measure of improvements in apathy and debriefing interviews to assess feedback from participants. Side effects that can occur from using HMDs were also measured. We recruited participants from a high socioeconomic status setting with a high education level, and the participation rate was 85% (17/20) most responses to measures were positive. Access to a wide range of freely available content and the absence of technical difficulties made the delivery of a VR reminiscence intervention highly feasible. Participants had improved semantic scores (t14=−3.27 P=.006) but not phonemic fluency scores (t14=0.55 P=.59) immediately after the intervention. Those with higher levels of apathy demonstrated the greatest cognitive improvements after a VR reminiscence experience, which was indicated by a strong positive relationship between the AES and semantic verbal fluency change scores postminus pre-VR (r=0.719 95% CI 0.327 to 0.900 P=.003). All participants enjoyed the experience despite 35% (6/17) of participants experiencing temporary side effects. This study provides initial evidence that it is feasible to use VR with HMDs for therapy to treat symptoms of apathy in older adults in residential aged care. However, there is a need to closely monitor the side effects of HMD use in older adults. Further research is needed using an active control group to compare the use of VR with traditional forms of reminiscence therapy.
Publisher: Public Library of Science (PLoS)
Date: 12-09-2012
Publisher: Public Library of Science (PLoS)
Date: 05-12-2018
Publisher: Wiley
Date: 15-06-1982
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2022
Publisher: Elsevier BV
Date: 09-2023
Publisher: S. Karger AG
Date: 2016
DOI: 10.1159/000448213
Abstract: b i Background/Aims: /i /b No set operational criteria for vascular cognitive impairment, no dementia (VCI-ND) have yet been established. The aim of this study is to undertake a systematic review to compare definitions of VCI-ND that have been used in cohort studies. b i Methods: /i /b Medline, PsycINFO and Embase were searched from inception to October 13, 2015. Initially, 3,142 records were screened, and 30 were included in this review. b i Results: /i /b No single set of criteria for defining VCI-ND was identified. VCI-ND b /b was broadly defined as an absence of dementia, cognitive impairment in at least one cognitive domain with signs of vascular involvement, and intact activities of daily living. b i Conclusion: /i /b Defining criteria will enable in iduals with VCI-ND to be efficiently compared across cohort studies to more accurately determine the prevalence and risk of dementia.
Publisher: Wiley
Date: 14-02-2011
DOI: 10.1002/GPS.2492
Publisher: Cold Spring Harbor Laboratory
Date: 05-09-2022
DOI: 10.1101/2022.09.01.506258
Abstract: We investigated how resting EEG measures are associated with risk factors for late-life cognitive impairment and dementia, including age, Apolipoprotein E ε4 (APOE-ε4) carriage and cardiometabolic burden. Resting EEG was recorded from 86 adults (50-80 years of age). Participants additionally completed the Addenbrooke’s Cognitive Examination (ACE) III and had blood drawn to assess APOE-ε4 carriage status and cardiometabolic burden. EEG power spectra were decomposed into sources of periodic and aperiodic activity to derive measures of aperiodic component slope and alpha (7-14 Hz) and beta (15-30 Hz) peak power and peak frequency. Alpha and beta peak power measures were corrected for aperiodic activity. The aperiodic component slope was correlated with ACE-III scores but not age. Alpha peak frequency decreased with age. In iduals with higher cardiometabolic burden had lower alpha peak frequencies and lower beta peak power. APOE-ε4 carriers had lower beta peak frequencies. Our findings suggest that the slope of the aperiodic component of resting EEG power spectra is more closely associated with measures of cognitive performance rather than chronological age in older adults.
Publisher: Elsevier BV
Date: 2023
Publisher: Center for Open Science
Date: 10-03-2020
Abstract: Higher and lower levels of alertness typically lead to a leftward and rightward bias in attention, respectively. This relationship between alertness and spatial attention potentially has major implications for health and safety. The current study examined alertness and spatial attention under simulated shiftworking conditions. Nineteen healthy right-handed participants (M=24.6±5.3 years, 11 males) completed a seven-day laboratory based simulated shiftwork study. Measures of alertness (Stanford Sleepiness Scale and Psychomotor Vigilance Task) and spatial attention (Landmark Task and Detection Task) were assessed across the protocol. Detection Task performance revealed slower reaction times and higher omissions of peripheral (compared to central) stimuli, with lowered alertness suggesting narrowed visuospatial attention and a slight left-sided neglect. There were no associations between alertness and spatial bias on the Landmark Task. Our findings provide tentative evidence for a slight neglect of the left-side and a narrowing of attention with lowered alertness. The possibility that one’s ability to sufficiently react to information in the periphery and the left-side may be compromised under conditions of lowered alertness highlights the need for future research to better understand the relationship between spatial attention and alertness under shiftworking conditions.
Publisher: Informa UK Limited
Date: 19-05-2016
DOI: 10.1080/13825585.2015.1048773
Abstract: Social and general cognitive abilities decline in late life. Those with high cognitive reserve display better general cognitive performance in old age however, it is unknown whether this is also the case for social cognition. A total of 115 healthy older adults, aged 60-85 years (m = 44, f = 71) were assessed using The Awareness of Social Inference Test (TASIT-R social cognition), the Lifetime of Experiences Questionnaire (LEQ cognitive reserve), and the Wechsler Abbreviated Scale of Intelligence (WASI-II general cognitive ability). The LEQ did not predict performance on any TASIT-R subtest: Emotion Evaluation Test (β = -.097, p = .325), Social Inference - Minimal (β = -.004, p = .972), or Social Inference - Enriched (β = -.016, p = .878). Sensitivity analyses using two alternative cognitive reserve measures, years of education and the National Adult Reading Test, supported these effects. Cognitive reserve was strongly related to WASI-II performance. Unlike general cognitive ability, social cognition appears unaffected by cognitive reserve. Findings contribute to the emerging understanding that cognitive reserve differentially affects in idual cognitive domains, which has implications for the theoretical understanding of cognitive reserve and its brain correlates. Cognitive measures unbiased by cognitive reserve may serve as best indicators of brain health, free of compensatory mechanisms.
Publisher: Elsevier BV
Date: 12-2018
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 17-11-2020
Abstract: Coronary artery bypass grafting (CABG) is known to improve heart function and quality of life, while rates of surgery‐related mortality are low. However, delirium and cognitive decline are common complications. We sought to identify preoperative, intraoperative, and postoperative risk or protective factors associated with delirium and cognitive decline (across time) in patients undergoing CABG. We conducted a systematic search of Medline, PsycINFO, EMBASE, and Cochrane (March 26, 2019) for peer‐reviewed, English publications reporting post‐CABG delirium or cognitive decline data, for at least one risk factor. Random‐effects meta‐analyses estimated pooled odds ratio for categorical data and mean difference or standardized mean difference for continuous data. Ninety‐seven studies, comprising data from 60 479 patients who underwent CABG, were included. Moderate to large and statistically significant risk factors for delirium were as follows: (1) preoperative cognitive impairment, depression, stroke history, and higher European System for Cardiac Operative Risk Evaluation (EuroSCORE) score, (2) intraoperative increase in intubation time, and (3) postoperative presence of arrythmia and increased days in the intensive care unit higher preoperative cognitive performance was protective for delirium. Moderate to large and statistically significant risk factors for acute cognitive decline were as follows: (1) preoperative depression and older age, (2) intraoperative increase in intubation time, and (3) postoperative presence of delirium and increased days in the intensive care unit. Presence of depression preoperatively was a moderate risk factor for midterm (1–6 months) post‐CABG cognitive decline. This meta‐analysis identified several key risk factors for delirium and cognitive decline following CABG, most of which are nonmodifiable. Future research should target preoperative risk factors, such as depression or cognitive impairment, which are potentially modifiable. URL: www.crd.york.ac.uk rospero/ Unique identifier: CRD42020149276.
Publisher: Informa UK Limited
Date: 27-02-2014
Publisher: American Medical Association (AMA)
Date: 03-2017
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.BIOPSYCHO.2018.09.002
Abstract: Oddball designs are widely used to investigate the sensitivity of the visual system to statistical regularities in sensory environments. However, the underlying mechanisms that give rise to visual mismatch responses remain unknown. Much research has focused on identifying separable, additive effects of stimulus repetition and stimulus appearance probability (expectation/surprise) but findings from non-oddball designs indicate that these effects also interact. We adapted the fast periodic visual stimulation (FPVS) unfamiliar face identity oddball design (Liu-Shuang et al., 2014) to test for both additive and interactive effects of stimulus repetition and stimulus expectation. In two experiments, a given face identity was presented at a 6 Hz periodic rate a different identity face (the oddball) appeared as every 7th image in the sequence (i.e., at 0.857 Hz). Electroencephalographic (EEG) activity was recorded during these stimulation sequences. In Experiment 1, we tested for surprise responses evoked by unexpected face image repetitions by replacing 10% of the commonly-presented oddball faces with exact repetitions of the base rate face identity image. In Experiment 2, immediately repeated or unrepeated face identity oddballs were presented in high and low presentation probability contexts (i.e., expected or surprising contexts), allowing assessment of expectation effects on responses to both repeated and unrepeated stimuli. Across both experiments objective (i.e., frequency-locked) visual mismatch responses driven by stimulus expectation were only found for oddball faces of a different identity to base rate faces (i.e., unrepeated identity oddballs). Our results show that immediate stimulus repetition (i.e., repetition suppression) can reduce or abolish expectation effects as indexed by EEG responses in visual oddball designs.
Publisher: Informa UK Limited
Date: 13-11-2018
DOI: 10.1080/13854046.2017.1400106
Abstract: There is a need for short, reliable, sensitive assessment tools to measure social cognition. The Awareness of Social Inference Test (TASIT) is an ecologically valid instrument that uses videos of actors engaged in everyday conversations to assess emotion perception, the ability to detect lies, sarcasm and sincerity, and the ability to judge what others are thinking, intending, feeling, and saying. A recently developed short version of TASIT retains the structure of the original test and its clinical sensitivity. In this paper, we compare TASIT-S performance in healthy adolescents, adults, and older adults as well as the effects of country (U.S.A. and Australia), English familiarity and gender. In this study 616 Australians including 226 adolescents (13-19) and 390 adults aged 20-75 + along with 180 U.S. residents (aged 20-74) completed one, two, or three parts of TASIT-S either face to face (Australians) or on-line (US residents). Results indicated that there were minor differences in TASIT-S performance (Part 3 only) based on country of residence and no significant effects for English familiarity in adolescents (not examined in adults). There were no gender effects. Young and middle aged adults (20-59) tended to perform better than adolescents and older adults on most parts of TASIT-S. In general, TASIT-S scores decreased moderately with advancing age. In conclusion, TASIT-S is a useful screen for social cognitive impairment in English speakers that is appropriate for use from adolescence through to older age. It produces comparable scores in the U.S.A. and Australia.
Publisher: Informa UK Limited
Date: 18-12-2020
Publisher: Wiley
Date: 25-09-2017
DOI: 10.1111/BPA.12556
Publisher: Informa UK Limited
Date: 08-06-2017
DOI: 10.1080/23279095.2017.1329146
Abstract: Cognitive reserve beneficially affects cognitive performance, even into advanced age. However, the benefits afforded by high cognitive reserve may not extend to all cognitive domains. This study investigated whether cognitive reserve differentially affects performance on cognitive tasks, in 521 cognitively healthy in iduals aged 60 to 98 years (Mage = 68, SD = 6.22, 287 female) years of education was used to index cognitive reserve. Cognitive performance variables assessed attention, executive functions, verbal memory, motor performance, orientation, perception of emotion, processing speed, and working memory. Bootstrapped regression analyses revealed that cognitive reserve was associated with attention, executive functions, verbal and working memory, and orientation and not significantly related to emotion perception, processing speed, or motor performance. Cognitive reserve appears to differentially affect in idual cognitive domains, which extends current theory that purports benefits for all domains. This finding highlights the possibility of using tests not (or minimally) associated with cognitive reserve, to screen for cognitive impairment and dementia in late life these tests will likely best track brain health, free of compensatory neural mechanisms.
Publisher: Elsevier BV
Date: 04-2017
Publisher: Center for Open Science
Date: 16-10-2020
Abstract: Current evidence suggests that the ability to detect and react to information under lowered alertness conditions might be more impaired on the left than the right side of space. This evidence derives mainly from right-handers being assessed in computer and paper-and-pencil spatial attention tasks. However, there are suggestions that left-handers might show impairments on the opposite (right) side compared to right-handers with lowered alertness, and it is unclear whether the impairments observed in the computer tasks have any real-world implications for activities such as driving. The current study investigated the alertness and spatial attention relationship under simulated monotonous driving in left- and right-handers. Twenty left-handed and 22 right-handed participants (15 males, mean age=23.6y, SD=5.0y) were assessed on a simulated driving task (lasting approximately 60 minutes) to induce a time-on-task effect. The driving task involved responding to stimuli appearing at six different horizontal locations on the screen, whilst driving in a 50km/h zone. Decreases in alertness and driving performance were evident with time-on-task in both handedness groups. We found handedness impacts reacting to lateral stimuli differently with time-on-task: right-handers reacted slower to the leftmost stimuli, while left-handers showed the opposite pattern (although not statistically significant) in the second compared to first half of the drive. Our findings support suggestions that handedness modulates the spatial attention and alertness interactions. The interactions were observed in a simulated driving task which calls for further research to understand the safety implications of these interactions for activities such as driving.
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.HLC.2016.09.002
Abstract: Older in iduals can now undergo invasive cardiovascular procedures without serious concern about mortality, and the numbers and proportions of the over 65s and 85s doing so in Australia has been increasing over the last 20 years. There is overwhelming evidence linking cardiovascular conditions to late-life (65 years and over) cognitive impairment and dementia including Alzheimer's Disease, primarily due to impaired cerebrovascularisation and cascading neuropathological processes. Somewhat paradoxically, these cardiovascular interventions, carried out with the primary aim of revascularisation, are not usually associated with short- or long-term improvements in cognitive function in older adults. We discuss factors associated with cognitive outcomes post-cardiovascular surgeries in patients over 65 years of age. There are many opportunities for future research: we know almost nothing about cognitive outcomes following invasive cardiac procedures in the oldest old (85 years and over) nor how to predict the cognitive/delirium outcome using pre-surgical data, and lastly, intervention opportunities exist both pre and postoperatively that have not been tested. As our population ages with increased cardiovascular burden and rates of cardiovascular interventions and surgeries, it is critical that we understand the cognitive consequences of these procedures, who is at greatest risk, and ways to optimise cognition.
Publisher: Frontiers Media SA
Date: 24-11-2022
DOI: 10.3389/FNHUM.2022.1051793
Abstract: Physical activity, sedentary behaviour and sleep are associated with cognitive function in older adults. However, these behaviours are not independent, but instead make up exclusive and exhaustive components of the 24-h day. Few studies have investigated associations between 24-h time-use composition and cognitive function in older adults. Of these, none have considered how the quality of sleep, or the context of physical activity and sedentary behaviour may impact these relationships. This study aims to understand how 24-h time-use composition is associated with cognitive function across a range of domains in healthy older adults, and whether the level of recreational physical activity, amount of television (TV) watching, or the quality of sleep impact these potential associations. 384 healthy older adults (age 65.5 ± 3.0 years, 68% female, 63% non-smokers, mean education = 16.5 ± 3.2 years) participated in this study across two Australian sites (Adelaide, n = 207 Newcastle, n = 177). Twenty-four-hour time-use composition was captured using triaxial accelerometry, measured continuously across 7 days. Total time spent watching TV per day was used to capture the context of sedentary behaviours, whilst total time spent in recreational physical activity was used to capture the context of physical activity (i.e., recreational accumulation of physical activity vs. other contexts). Sleep quality was measured using a single item extracted from the Pittsburgh Sleep Quality Index. Cognitive function was measured using a global cognition index (Addenbrooke’s Cognitive Examination III) and four cognitive domain composite scores (derived from five tests of the Cambridge Neuropsychological Test Automated Battery: Paired Associates Learning One Touch Stockings of Cambridge Multitasking Reaction Time Verbal Recognition Memory). Pairwise correlations were used to describe independent relationships between time use variables and cognitive outcomes. Then, compositional data analysis regression methods were used to quantify associations between cognition and 24-h time-use composition. After adjusting for covariates and false discovery rate there were no significant associations between time-use composition and global cognition, long-term memory, short-term memory, executive function, or processing speed outcomes, and no significant interactions between TV watching time, recreational physical activity engagement or sleep quality and time-use composition for any cognitive outcomes. The findings highlight the importance of considering all activities across the 24-h day against cognitive function in older adults. Future studies should consider investigating these relationships longitudinally to uncover temporal effects.
Publisher: S. Karger AG
Date: 29-06-2012
DOI: 10.1159/000339234
Abstract: b i Background/Aim: /i /b The contribution of cerebrovascular dysfunction to the manifestation of dementia and cognitive decline in late life is gaining increased attention. We aimed to systematically review evidence for associations between dementia or aging and cerebrovascular function as measured using transcranial Doppler (TCD) examination. b i Methods: /i /b A total of 1,172 articles were retrieved from PsychInfo and PubMed searches, and 34 relevant articles were identified using a variety of TCD methods. b i Results: /i /b The pulsatility index (vessel resistance), spontaneous emboli and cerebrovascular reactivity to hyper-/hypocapnia appeared good discriminators of dementia. Aging was associated with a slowing in blood flow velocity. b i Conclusion: /i /b TCD ultrasonography is inexpensive, portable and well tolerated by aged and demented subjects. The technique stands to make a valuable contribution to the knowledge regarding the underlying functional biology of age-related cognitive change and dementia.
Publisher: Elsevier BV
Date: 12-2009
DOI: 10.1016/J.PSYCHRES.2008.10.026
Abstract: There is overlap between the behavioural symptoms and disturbances associated with Attention-Deficit/Hyperactivity Disorder (AD/HD) and sleep problems. The aim of this study was to examine the extent of overlap in cognitive and electrophysiological disturbances identified in children experiencing sleep problems and children with AD/HD or both. Four groups (aged 7-18) were compared: children with combined AD/HD and sleep problems (n=32), children with AD/HD (n=52) or sleep problems (n=36) only, and children with neither disorder (n=119). Electrophysiological and cognitive function measures included: absolute EEG power during eyes open and eyes closed, event-related potential (ERP) components indexing attention and working memory processes (P3), and a number of standard neuropsychological tests. Children with symptoms of both AD/HD and sleep problems had a different profile from those of children with either AD/HD or sleep problems only. These findings suggest it is unlikely that disturbances in brain and cognitive functioning associated with sleep problems also give rise to AD/HD symptomatology and consequent diagnosis. Furthermore, findings suggest that children with symptoms of both AD/HD and sleep problems may have a different underlying aetiology than children with AD/HD-only or sleep problems-only, perhaps requiring unique treatment interventions.
Publisher: Wiley
Date: 18-08-2015
DOI: 10.1002/ACN3.231
Publisher: Oxford University Press (OUP)
Date: 24-11-2009
Publisher: Elsevier BV
Date: 07-2020
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.CLINPH.2014.09.015
Abstract: To systematically evaluate evidence for configural and affective face processing abnormalities as measured by the N170 and Vertex Positive Potential (VPP) event-related potential components, and analogous M170 magnetoencephalography (MEG) component, in neurological and psychiatric disorders. 1251 unique articles were identified using PsychINFO and PubMed databases. Sixty-seven studies were selected for review, which employed various tasks to measure the N170, M170 or VPP the 13 neurological sychiatric conditions were Attention-Deficit Hyperactivity Disorder (ADHD), Alcohol Dependence, Alzheimer's Disease, Autism Spectrum Disorders (ASDs), Bipolar Disorder, Bulimia Nervosa, Fibromyalgia, Huntington's Disease, Major Depressive Disorder, Parkinson's Disease, Prosopagnosia, Schizophrenia and Social Phobia. Smaller N170 and VPP litudes to faces compared to healthy controls were consistently reported in Schizophrenia but not in ASDs. In Schizophrenia N170 and VPP measures were not correlated with clinical symptoms. Findings from other disorders were highly inconsistent however, reported group differences were almost always smaller litudes or slower latencies to emotional faces in disordered groups regardless of diagnosis. Results suggest that N170/VPP abnormalities index non-specific facial affect processing dysfunction in these neurological and psychiatric conditions, reflecting social impairments being broadly characteristic of these groups. The N170 and analogous components hold promise as diagnostic and treatment monitoring biomarkers for social dysfunction.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2008
Publisher: Elsevier BV
Date: 07-2023
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.CLINPH.2007.09.119
Abstract: This study examines the utility of new measures of event-related spatio-temporal waves in the EEG as a marker of ADHD, previously shown to be closely related to the P3 ERP in an adult s le. Wave activity in the EEG was assessed during both an auditory Oddball and a visual continuous performance task (CPT) for an ADHD group ranging in age from 6 to 18 years and comprising mostly Combined and Inattentive subtypes, and for an age and gender matched control group. The ADHD subjects had less wave activity at low frequencies ( approximately 1 Hz) during both tasks. For auditory Oddball targets, this effect was shown to be related to smaller P3 ERP litudes. During CPT, the approximately 1 Hz wave activity in the ADHD subjects was inversely related to clinical and behavioral measures of hyperactivity and impulsivity. CPT wave activity at approximately 1 Hz was seen to "normalise" following treatment with stimulant medication. The results identify a deficit in low frequency wave activity as a new marker for ADHD associated with levels of hyperactivity and impulsivity. The marker is evident across a range of tasks and may be specific to ADHD. While lower approximately 1 Hz activity partly accounts for reduced P3 ERPs in ADHD, the effect also arises for tasks that do not elicit a P3. Deficits in behavioral inhibition are hypothesized to arise from underlying dysregulation of cortical inhibition.
Publisher: Center for Open Science
Date: 20-12-2019
Abstract: Background and Objectives: Apathy is a common symptom in neurological disorders including dementia and is associated with a faster rate of cognitive decline, reduced quality of life and high carer burden. A lack of effective pharmacological treatments for apathy has placed an emphasis on non-pharmacological interventions. Virtual reality (VR) using head-mounted displays (HMD) has been successfully used in exposure and distraction-based therapies, however, there is limited research in using HMDs for symptoms of neurological disorders. This feasibility study assessed if VR using HMDs could be used to deliver tailored reminiscence therapy. Willingness to participate response rates to measures time taken to create tailored content and technical problems were examined.Methods: A mixed methods study was conducted in a s le of older adults residing in aged care, 17 participants were recruited. Apathy was measured using the Apathy Evaluation Scale, verbal fluency was used as a proxy measure of improvements in apathy and debriefing interviews assessed feedback from participants. Side effects that can occur from using HMDs were also measured. Results: Those with higher levels of apathy demonstrated the greatest cognitive improvements after a VR reminiscence experience. All participants enjoyed the experience despite 35% of participants experiencing temporary side effects.Implications: There is a need to closely monitor side effects from HMD use in older adults. This study provides initial evidence that it is feasible to use VR with HMDs for therapy to treat symptoms of apathy in older adults in residential aged care.
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.SLEEP.2016.02.002
Abstract: Cognitive decrements, problematic behaviors, and increased cerebral blood flow velocities (CBFVs) have been reported in children aged 3-7 years with sleep-disordered breathing (SDB). Whether similar impairments exist in younger children or those with behavioral insomnia of childhood (BIC) remains unclear. This study aimed to compare cognition and temperament in children aged 1-5 years with SDB or BIC to healthy control children, and to investigate whether cognitive or behavioral deficits associated with sleep problems are related to changes in CBFV. Toddlers and preschool-aged children (12-67 months) who had been referred for the clinical evaluation of SDB (n = 20) or BIC (n = 13) and a comparative s le of non-snoring healthy sleepers (controls n = 77) were recruited from the community. Children underwent cognitive assessment (Mullen's Scale of Early Learning) and measurement of resting bilateral CBFV in the middle cerebral artery (MCA) using Transcranial Doppler. Parents completed temperament scales (Early Childhood or Childhood Behavior Questionnaire), a sleep problem questionnaire (Pediatric Sleep Problem Survey Instrument) and performed home-based pediatric sleep monitoring (Actigraphy and Sleep Diary). SDB children demonstrated impaired receptive skills, more hyperactive and energetic temperaments, and higher bilateral CBFV than controls and children with BIC. Logistic regression analyses indicated that impaired cognition, temperamental difficulties, and increased CBFV are independently associated with SDB. During early childhood, problematic temperaments, cognitive deficits, and altered cerebrovascular functioning are associated with SDB but not BIC. CBFV does not appear to mediate these daytime deficits and instead may be an independent outcome of SDB. The findings support the need for an early intervention in pediatric SDB.
Publisher: Informa UK Limited
Date: 06-01-2014
DOI: 10.1080/17470919.2013.873737
Abstract: It is now common practice, in digital communication, to use the character combination ":-)", known as an emoticon, to indicate a smiling face. Although emoticons are readily interpreted as smiling faces, it is unclear whether emoticons trigger face-specific mechanisms or whether separate systems are utilized. A hallmark of face perception is the utilization of regions in the occipitotemporal cortex, which are sensitive to configural processing. We recorded the N170 event-related potential to investigate the way in which emoticons are perceived. Inverting faces produces a larger and later N170 while inverting objects which are perceived featurally rather than configurally reduces the litude of the N170. We presented 20 participants with images of upright and inverted faces, emoticons and meaningless strings of characters. Emoticons showed a large litude N170 when upright and a decrease in litude when inverted, the opposite pattern to that shown by faces. This indicates that when upright, emoticons are processed in occipitotemporal sites similarly to faces due to their familiar configuration. However, the characters which indicate the physiognomic features of emoticons are not recognized by the more laterally placed facial feature detection systems used in processing inverted faces.
Publisher: Elsevier BV
Date: 08-2012
DOI: 10.1016/J.SLEEP.2012.02.003
Abstract: Sleep is critical for optimal cognitive function, but as we age both cognitive impairment and sleep problems increase. Longitudinal, population-based studies can be used to investigate temporal relationships between sleep and cognition. A total of 2012 cognitively unimpaired in iduals 65 years and over were drawn from the MRC Cognitive Function and Ageing Study (CFAS). They answered self-reported measures including: insomnia symptoms and age of onset, night time wakings, snoring, sleep onset latency, napping, daytime sleepiness and duration of night time sleep. Cognition was measured via the Mini-Mental State Examination. It was found that daytime napping at baseline was associated with a lower risk of cognitive decline at two and 10 years, and that obtaining ≤6.5h of night-time sleep and excessive daytime sleepiness at baseline were associated with an increased risk at 10 years. Daytime napping, night-time sleep duration, and excessive daytime sleepiness may be modifiable behaviours open to intervention strategies, or, clinical indicators of future decline in older in iduals.
Publisher: Wiley
Date: 27-08-2019
DOI: 10.1111/BPA.12773
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2020
Publisher: Springer Science and Business Media LLC
Date: 12-2017
Publisher: Springer Science and Business Media LLC
Date: 13-06-2022
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2005
DOI: 10.1142/S0219635205000744
Abstract: The effects of methylphenidate (MPH) on 32 healthy human male volunteers (aged 18 to 25 years, mean age=22.26) were examined using a within-subject design. Each participant attended six testing periods, held once per week. Within each testing period, three repeat testing sessions were undertaken: pre-medication, on-medication and two hours post-medication. In these sessions, dose was manipulated (placebo, 5 mg, 15 mg or 45 mg) according a double-blind placebo design. In this report, we focus on behavioral, autonomic arousal (heart rate, skin conductance) and psychophysiological (ERP) data acquired during the working memory task. We found increased autonomic arousal (heart rate, skin conductance and blood pressure) with MPH. A linear reduction in reaction time, omission errors and target P3 latency, and a corresponding increase in background P3 litude was observed with increased MPH dose. The relationship between these measures supported an increase in performance and underlying brain function with MPH. To our knowledge, this is the first paper to use behavioral, arousal and electrophysiological measures in an integrative approach to study the effects of MPH on healthy adults.
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.NEUROIMAGE.2017.12.029
Abstract: Repeated stimulus presentation leads to reductions in responses of cortical neurons, known as repetition suppression or stimulus-specific adaptation. Circuit-based models of repetition suppression provide a framework for investigating patterns of repetition effects that propagate through cortical hierarchies. To further develop such models it is critical to determine whether (and if so, when) repetition effects are modulated by factors such as expectation and attention. We investigated whether repetition effects are influenced by perceptual expectations, and whether the time courses of each effect are similar or distinct, by presenting pairs of repeated and alternating face images and orthogonally manipulating expectations regarding the likelihood of stimulus repetition. Event-related potentials (ERPs) were recorded from n = 39 healthy adults, to map the spatiotemporal progression of stimulus repetition and stimulus expectation effects, and interactions between these, using mass univariate analyses. We also tested for another expectation effect that may contribute to repetition effects in many previous experiments: that repeated stimulus identities are predictable after seeing the first stimulus in a trial, but unrepeated stimulus identities cannot be predicted. Separate blocks were presented with predictable and unpredictable alternating face identities. Multiple repetition and expectation effects were identified between 99 and 800ms from stimulus onset, which did not statistically interact at any point and exhibited distinct spatiotemporal patterns of effects. Repetition effects in blocks with predictable alternating faces were smaller than in unpredictable alternating face blocks between 117-179 ms and 506-652ms, and larger between 246 and 428ms. The distinct spatiotemporal patterns of repetition and expectation effects support separable mechanisms underlying these phenomena. However, previous studies of repetition effects, in which the repeated (but not unrepeated) stimulus was predictable, are likely to have conflated repetition and stimulus predictability effects.
Publisher: Frontiers Media SA
Date: 11-08-2021
Abstract: Background: Transcatheter aortic valve implantation (TAVI) has become the standard-of-care for treatment of severe symptomatic aortic stenosis and is also being increasingly recommended for low-risk patients. While TAVI boasts positive post-procedural outcomes, it is also associated with cognitive complications, namely delirium and cognitive decline. There is a pressing need for accurate risk tools which can identify TAVI patients at risk of delirium and cognitive decline, as risk scores designed for general cardiovascular surgery fall short. The present effect-finding exploratory study will assess the utility of various measures in the context of aging and frailty in predicting who will and who will not develop delirium or cognitive impairment following TAVI. The measures we propose include gait, visual symptoms, voice, swallowing, mood and sleep. Methods: This is an observational prospective cohort study focused on identifying pre-procedural risk factors for the development of delirium and cognitive decline following TAVI. Potential risk factors will be measured prior to TAVI. Primary outcomes will be post-procedure cognitive decline and delirium. Secondary outcomes include activities of daily living, quality of life, and mortality. Delirium presence will be measured on each of the first 2 days following TAVI. All other outcomes will be assessed at 3-, 6-, and 12-months post-operatively. A series of logistic regressions will be run to investigate the relationship between potential predictors and outcomes (presence vs. absence of either delirium or cognitive decline). Discussion: This study will assess the strengths of associations between a range of measures drawn from frailty and aging literature in terms of association with cognitive decline and delirium following TAVI. Identified measures can be used in future development of TAVI risk prediction models, which are essential for the accurate identification of cognitive at-risk patients and successful application of pre-procedural interventions. Clinical Trial Registration: This trial is registered with the Australian New Zealand Clinical Trials Registry. [ bit.ly/2PAotP5 ], [ACTRN12618001114235].
Publisher: SAGE Publications
Date: 20-03-2021
Abstract: Dementia has become a major public health concern globally. With no cure available and strong evidence for modifiable risk factors, it is imperative that the public are knowledgeable about dementia and to reduce their risk. The aim of this study was to measure the knowledge of dementia and its risk factors in the Australian public, as well as the number and type of information sources used. An online survey promoted through various social media platforms was completed by 596 Australian adults aged 18–78 years (59% aged 18–44 years 78% female). Eighty-eight percent of respondents were able to recognise dementia from a vignette, more so from a moderate than from a mild symptom vignette. Only 19% of respondents had a good understanding of dementia, that is describing impairment in both cognition and function. Ninety-five percent of respondents recognised that genetics and old age contributed to a person getting dementia. However, respondents had poor knowledge of empirically supported modifiable risk factors, with most viewed as likely contributors to dementia at chance levels (50%) or below. Respondents reported using informal information sources more often than formal information sources to learn about dementia. The public appear to be able to recognise the symptoms of dementia but lack understanding of how dementia impacts both a person’s cognitive functioning and ability to perform everyday tasks. Furthermore, the public remain largely unaware of empirically supported modifiable risk factors that contribute to the development of dementia. It is imperative that the public are educated on how to access and evaluate dementia-related information sources in order to increase their knowledge and understanding of dementia.
Publisher: Oxford University Press (OUP)
Date: 22-07-2017
Abstract: The oldest-old (aged ≥85 years) are the fastest growing age group, with the highest risk of cognitive impairment and dementia. This study investigated whether cognitive reserve applies to the oldest-old. This has implications for cognitive interventions in this age group. Baseline and 5-year follow-up data from the Newcastle 85+ Study were used (N = 845, mean age = 85.5, 38% male). A Cognitive Reserve Index (CRI) was created, including: education, social class, marital status, engagement in mental activities, social participation, and physical activity. Global (Mini-Mental State Examination) and domain specific (Cognitive Drug Research Battery subtests assessing memory, attention, and speed) cognitive functions were assessed. Dementia diagnosis was determined by health records. Logistic regression analysis examined the association between CRI scores and incident dementia. Mixed effects models investigated baseline and longitudinal associations between the CRI scores and cognitive function. Analyses controlled for sex, age, depression, and cardiovascular disease history. Higher reserve associated with better cognitive performance on all baseline measures, but not 5-year rate of change. The CRI associated with prevalent, but not incident dementia. In the oldest-old, higher reserve associated with better baseline global and domain-specific cognitive function and reduced risk of prevalent dementia but not cognitive decline or incident dementia. Increasing reserve could promote cognitive function in the oldest-old. The results suggest there would be little impact on trajectories, but replication is needed. Development of preventative strategies would benefit from identifying the role of each factor in building reserve and why rate of change is not affected.
Publisher: Center for Open Science
Date: 13-12-2019
Abstract: The use of head-mounted displays (HMD) for virtual reality (VR) application-based purposes including therapy, rehabilitation, and training is increasing. Despite advancements in VR technologies, many users still experience sickness symptoms. VR sickness may be influenced by technological differences within HMDs such as resolution and refresh rate, however VR content also plays a significant role. The primary objective of this systematic review and meta-analysis was to examine the literature on HMD’s that report Simulator Sickness Questionnaire (SSQ) scores to determine the impact of content. User factors associated with VR sickness were also examined. A systematic search was conducted according to PRISMA guidelines. Fifty-five articles met inclusion criteria, representing 3,016 participants (mean age range 19.5-80 41% female). Findings show gaming content recorded the highest total SSQ mean 34.26 (95%CI 29.57-38.95). VR sickness profiles were also influenced by visual stimulation, locomotion and exposure times. Older s les (mean age ≥35 years) scored significantly lower total SSQ means than younger s les, however these findings are based on a small evidence base as a limited number of studies included older users. No sex differences were found. Across all types of content, the pooled total SSQ mean was relatively high 28.00 (95%CI 24.66-31.35) compared with recommended SSQ cut-off scores. These findings are of relevance for informing future research and the application of VR in different contexts.
Publisher: Springer Science and Business Media LLC
Date: 25-11-2021
DOI: 10.1186/S12889-021-12220-7
Abstract: There are well established modifiable risk factors for late-life dementia. These risk factors account for over 30% of population attributable dementia risk and accrue over the lifespan. Young adults have the greatest potential to reduce their own risk for dementia. This study aimed to investigate what young Australian adults know about dementia and its risk factors, and further, how they estimated these risks. An online survey promoted through various social media platforms was completed by 604 young Australian adults aged 18–44 years of age. Seventy percent of participants had a limited understanding of dementia (identifying cognitive or functional impairment), 25% had a good understanding, with 5% having no understanding. Twenty percent of respondents thought there were no modifiable risk factors for dementia. Less the half of participants agreed with two of the nine established dementia risk factors (hearing loss in midlife and education in early life), with over half of participants agreeing to the remaining seven risk factors. Females consistently judged the risks conferred by the nine established dementia risk factors to be higher than males. Those who were lonely judged the dementia risk conferred by loneliness to be higher than those who were not lonely and smokers judged the dementia risk conferred by smoking to be less than non-smokers. Young adults have the greatest potential to change their dementia risk, and these findings show that there are important gaps in knowledge of dementia and its risk factors in this group.
Publisher: Cold Spring Harbor Laboratory
Date: 08-05-2018
DOI: 10.1101/316786
Abstract: Oddball designs are widely used to investigate the sensitivity of the visual system to statistical regularities in sensory environments. However, the underlying mechanisms that give rise to visual mismatch responses remain unknown. Much research has focused on identifying separable, additive effects of stimulus repetition and stimulus appearance probability (expectation/surprise) but findings from non-oddball designs indicate that these effects also interact. We adapted the fast periodic visual stimulation (FPVS) unfamiliar face identity oddball design (Liu-Shuang et al., 2014) to test for both additive and interactive effects of stimulus repetition and stimulus expectation. In two experiments, a given face identity was presented at a 6 Hz periodic rate a different identity face (the oddball) appeared as every 7 th image in the sequence (i.e., at 0.857 Hz). Electroencephalographic (EEG) activity was recorded during these stimulation sequences. In Experiment 1, we tested for surprise responses evoked by unexpected face image repetitions by replacing 10% of the commonly-presented oddball faces with exact repetitions of the base rate face identity image. In Experiment 2, immediately repeated or unrepeated face identity oddballs were presented in high and low presentation probability contexts (i.e., expected or surprising), allowing assessment of expectation effects on responses to both repeated and unrepeated stimuli. Across both experiments objective (i.e., frequency-locked) visual mismatch responses driven by stimulus expectation were only found for oddball faces of a different identity to base rate faces (i.e., unrepeated identity oddballs). Our results show that immediate stimulus repetition (i.e., repetition suppression) can reduce or abolish expectation effects as indexed by EEG responses in visual oddball designs. - We studied visual mismatch responses with a fast periodic oddball design - Our design cleanly separates immediate stimulus repetition and expectation effects - Stimulus expectation effects were only present for unrepeated stimuli - Immediate stimulus repetition reduced EEG expectation effects
Publisher: Cold Spring Harbor Laboratory
Date: 12-05-2019
DOI: 10.1101/634873
Abstract: Cardiometabolic diseases and risk factors increase the risk of late-life cognitive impairment and dementia, and have also been associated with detrimental grey and white matter changes. However the functional brain changes associated with cardiometabolic health in late-life are unclear. We sought to characterise these functional changes by recording event-related potentials (ERPs) during a n-back working memory task (0, 1 and 2 back) in 85 adults (60% female) between 50 and 80 years of age. Due to a stratified recruitment approach, participants varied widely regarding cognitive function and cardiometabolic health. Standard and objective cut-offs for high blood glucose, waist to hip ratio (i.e. obesity), high blood cholesterol, and hypertension were employed to generate a summative score for cardiometabolic burden (none, one, or two or more above cut-off). Mixed effects modelling (covarying for age and gender) revealed no statistically significant associations between cardiometabolic burden and visual P1 and N1 component litudes. There was a significant effect for the P3b component: as cardiometabolic burden increased, P3b litude decreased. We show that cardiometabolic factors related to the development of cognitive impairment and dementia in late-life associate with functional brain activity, as recorded via ERPs. Findings have relevance for the monitoring of lifestyle interventions (typically targeting cardiometabolic factors) in ageing, as ERPs may provide a more sensitive measure of change than cognitive performance. Further, our results raise questions related to the findings of a broad range of ERP studies where the groups compared may differ in their cardiometabolic health status (not only in psychological symptomatology).
Publisher: Cold Spring Harbor Laboratory
Date: 22-09-2023
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2017
End Date: 2021
Funder: National Health and Medical Research Council
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