ORCID Profile
0000-0002-3869-4920
Current Organisation
University of the Sunshine Coast
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Psychology | Biological Psychology (Neuropsychology, Psychopharmacology, | Motor Control | Psychological Methodology, Design And Analysis | Learning, Memory, Cognition And Language | Sensory Processes, Perception And Performance | Health, Clinical And Counselling Psychology | Developmental Psychology And Ageing
Behavioural and cognitive sciences | Biological sciences | Nervous system and disorders | Health related to ageing |
Publisher: Wiley
Date: 12-2020
DOI: 10.1002/ALZ.037853
Publisher: Informa UK Limited
Date: 2006
Publisher: Springer Science and Business Media LLC
Date: 02-2021
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.CONCOG.2017.04.019
Abstract: A capacity model of mindfulness is adopted to differentiate the cognitive faculty of mindfulness from the metacognitive processes required to cultivate this faculty in mindfulness training. The model provides an explanatory framework incorporating both the developmental progression from focussed attention to open monitoring styles of mindfulness practice, along with the development of equanimity and insight. A standardised technique for activating these processes without the addition of secondary components is then introduced. Mindfulness-based interventions currently available for use in randomised control trials introduce components ancillary to the cognitive processes of mindfulness, limiting their ability to draw clear causative inferences. The standardised technique presented here does not introduce such ancillary factors, rendering it a valuable tool with which to investigate the processes activated in mindfulness practice.
Publisher: Springer Science and Business Media LLC
Date: 03-09-2020
Publisher: Springer Science and Business Media LLC
Date: 05-06-2017
DOI: 10.1038/S41598-017-03016-0
Abstract: Cognitive stimulation has been proposed as a non-pharmacological intervention to be used in primary, secondary and tertiary prevention approaches for Alzheimer’s disease. A common familial Alzheimer’s disease transgenic model showed heightened levels of the stress hormone, corticosterone. When exposed to periodic enhanced cognitive stimulation, these animals demonstrated further heightened levels of corticosterone as well as increased Aβ pathology. Hence, Alzheimer’s disease may be associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction, causing stimulatory environments to become stress-inducing, leading to a glucocorticoid-pathology cycle contributing to further Aβ release and plaque formation. This finding suggests that stimulation-based interventions and local environments for people with Alzheimer’s disease need to be designed to minimise a stress response that may exacerbate brain pathology.
Publisher: Springer Science and Business Media LLC
Date: 03-12-2020
DOI: 10.1038/S41598-020-78343-W
Abstract: Mindfulness has been shown to improve attentional performance, which is known to decline in aging. Long-latency electroencephalographic (EEG) event-related potential (ERP) changes have been reported immediately after mindfulness training, however the enduring stability of these effects is unknown. Furthermore, the ability of mindfulness to impact earlier stages of information processing is unclear. We examined neural activation using high density EEG in older adults engaged in mindfulness training to examine the long-term stability of training effects. After 6 months of training, mindfulness practitioners displayed enhanced neural activation during sensory encoding and perceptual processing of a visual cue. Enhanced perceptual processing of a visual cue was associated with increased neural activation during post-perceptual processing of a subsequent target. Similar changes were not observed in a control group engaged in computer-based attention training over the same period. Neural changes following mindfulness training were accompanied by behavioural improvements in attentional performance. Our results are suggestive of increased efficiency of the neural pathways subserving bottom-up visual processing together with an enhanced ability to mobilise top-down attentional processes during perceptual and post-perceptual processing following mindfulness training. These results indicate that mindfulness may enhance neural processes known to deteriorate in normal aging and age-related neurodegenerative diseases.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Wiley
Date: 07-2018
Publisher: Wiley
Date: 02-2007
Publisher: Wiley
Date: 07-2011
Publisher: Wiley
Date: 12-2020
DOI: 10.1002/ALZ.045477
Publisher: Wiley
Date: 07-2012
Publisher: Springer Science and Business Media LLC
Date: 15-11-2017
DOI: 10.1038/S41539-017-0014-5
Abstract: Although predictors of academic success have been identified in young adults, such predictors are unlikely to translate directly to an older student population, where such information is scarce. The current study aimed to examine cognitive, psychosocial, lifetime, and genetic predictors of university-level academic performance in older adults (50–79 years old). Participants were mostly female (71%) and had a greater than high school education level ( M = 14.06 years, SD = 2.76), on average. Two multiple linear regression analyses were conducted. The first examined all potential predictors of grade point average (GPA) in the subset of participants who had volunteered s les for genetic analysis ( N = 181). Significant predictors of GPA were then re-examined in a second multiple linear regression using the full s le ( N = 329). Our data show that the cognitive domains of episodic memory and language processing, in conjunction with midlife engagement in cognitively stimulating activities, have a role in predicting academic performance as measured by GPA in the first year of study. In contrast, it was determined that age, IQ, gender, working memory, psychosocial factors, and common brain gene polymorphisms linked to brain function, plasticity and degeneration ( APOE , BDNF , COMT , KIBRA, SERT ) did not influence academic performance. These findings demonstrate that ageing does not impede academic achievement, and that discrete cognitive skills as well as lifetime engagement in cognitively stimulating activities can promote academic success in older adults.
Publisher: Cambridge University Press (CUP)
Date: 12-10-2023
Abstract: Cognitive impairment is common post-stroke. There is a need to understand patterns of early cognitive recovery post-stroke to guide both clinical and research practice. The aim of the study was to map the trajectory of cognitive recovery during the first week to 90-days post-stroke using serial computerised assessment. An observational cohort study recruited consecutive stroke patients admitted to a stroke unit within 48 hours of onset. Cognitive function was assessed using the computerised Cambridge Neuropsychological Test Automated Battery (CANTAB) daily for seven days, then 14, 30 and 90 days post-stroke. The CANTAB measured visual episodic memory and learning, information processing speed, visuo-spatial working memory, complex sustained attention and mental flexibility. Repeated measures MANOVA/ANOVA with Least Squares Difference post-hoc analyses were performed to ascertain significant change over time. Forty-eight participants, mean age 73, primarily mild, ischaemic stroke, completed all assessment timepoints. There was a trajectory of early, global cognitive improvement, indicative of a post-stroke delirium, that largely stabilised between 6 and 14-days post-stroke. Change over time was examined within each cognitive test, with one measure stabilising by day 6 (Reaction Time) and others detecting improving performances up to 14 days post-stroke. Serial, computerised cognitive assessment can effectively map post-stroke cognitive recovery and revealed an early phase of global improvement over 14 days that is evidence for an acute post-stroke delirium. Resolution of post-stroke delirium in the second week following mild stroke indicates more extensive neuropsychological testing may be undertaken earlier than previously thought.
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.NEULET.2019.01.029
Abstract: Aging is associated with a decline in performance and speed of attentional processing. Mindfulness has been shown to enhance attentional performance, however evidence of this is lacking in aging cohorts. A longitudinal RCT was conducted to examine the effect of mindfulness training on attentional performance in healthy older adults (n = 49) together with an active control computer-based attention training group (n = 30). While both groups displayed decreased N2 litudes at frontal and central regions during an auditory oddball task after training, only the mindfulness group showed reductions in frontal N2 and P3 latency. These results suggest that programs targeting sustained attention may result in efficient allocation of attentional resources in older adults. In particular, mindfulness may enhance the speed of attentional processes which are known to decline in aging, thereby providing benefits against age-related cognitive decline.
Publisher: SAGE Publications
Date: 29-06-2020
Abstract: Recent research findings suggest the prevalence of loneliness is increasing in middle-aged adults parenting children, challenging the notion this demographic is typically at low risk of loneliness. The current study applied the cognitive discrepancy model as theoretical foundation to investigate the variance of in idual and situational variables contributing to perceived closeness and support and consequently loneliness. Structural equation modeling was employed to identify multivariate contributors associated with parental loneliness in 323 parents with an average age of 37.69 ( SD = 5.96) years. Results support the theoretical proposition that in idual factors, rather than situational, contribute to a greater variance of a perceived gap in relationship closeness and support. It was found that emotional competence, ability to forgive, emotional stability, extraversion, and lower mood levels are significant contributors to a small cognitive gap in perceived relationship closeness and protective against parental loneliness. Relationship status contributed a weak direct effect over perceived relationship closeness and support. Situational factors, including number of children and household income, were non-significant risks for loneliness. Overall, the model accounted for 65% of perceived relationship closeness and support and 85% of loneliness. The limitation of small number of male participants is discussed with regard to the existing research gap investigating male loneliness. A Pathway to Loneliness Risk Model is proposed, demonstrating that through increasing an in idual’s intrapersonal and interpersonal resources and challenging negative cognitive biases and maladaptive schemas regarding an in idual’s perception of their relationships, may lead to a reduction in the in idual’s risk for loneliness.
Publisher: Oxford University Press (OUP)
Date: 22-01-2021
Abstract: Prevention of frailty is paramount in older adults. We evaluated the efficacy of a tailored multidomain intervention, monitored with the My Active and Healthy Aging platform, in reducing conversion from a prefrail status to overt frailty and preventing decline in quality of life. We performed a multicentre, multicultural, randomised control study. The effects of multidomain interventions on frailty parameters, quality of life, physical, cognitive, psychosocial function, nutrition and sleep were evaluated in a group of 101 prefrail older subjects and compared with 100 prefrail controls, receiving general health advice. At the 12-month assessment, controls showed a decline in quality of life that was absent in the active group. In addition, active participants showed an increase in mood and nutrition function. No effect on remaining parameter was observed. Our study supports the use of personalised multidomain intervention, monitored with an information and communication technology platform, in preventing quality of life decline in older adults.
Publisher: Elsevier BV
Date: 08-2020
Publisher: Wiley
Date: 19-06-2014
DOI: 10.1111/ENE.12488
Abstract: Longitudinal studies of mild cognitive impairment (MCI) report that a sizeable proportion of MCI cases revert to normal levels of functioning over time. The rate of recovery from MCI indicates that existing MCI diagnostic criteria result in an unacceptably high rate of false positive diagnoses and lack adequate sensitivity and specificity. The aim of the present study was to identify a set of neuropsychological measures able to differentiate between true positive cases of MCI from those who were unimpaired at 11 months' follow-up. A discriminant function analysis identified that a combination of measures of complex sustained attention, semantic memory, working memory, episodic memory and selective attention correctly classified outcome in more than 80% of cases. The rate of false positive diagnoses (5.93%) was considerably lower than is evident in previously published MCI studies. The results of the present study indicate that the rate of false positive MCI diagnoses can be significantly reduced through the use of sensitive and specific neuropsychological measures of memory and non-memory functions.
Publisher: Cambridge University Press (CUP)
Date: 02-2022
DOI: 10.1017/BRIMP.2021.3
Abstract: The Montreal Cognitive Assessment (MoCA) is routinely used during the early assessment of people after stroke to indicate cognitive effects and inform clinical decision-making. The purpose of this study was to examine the relationship between cognition in the first week post-stroke and personal and instrumental activities of daily skills at 1 month and 3 months post-stroke. A prospective cohort study consecutively recruited people admitted to the acute stroke ward. Acute cognitive status was measured using the MoCA within 1 week post-stroke onset. Functional outcomes were measured using the Functional Independence Measure (FIM) and the Australian Modified Lawton’s Instrumental Activities of Daily Living Scale (Lawton’s) at 1 month and 3 months post-stroke. Fifty participants with predominantly mild stroke ( n = 47) and mean age of 69.8 achieved a mean MoCA score of 23.1. Controlling for age, the MoCA was associated with the overall FIM score at 1 month ( P = 0.02). It was nearing significance for the Lawton’s at 1 month ( P = 0.06) but was not associated with either outcome at 3 months. A score of less than 23 on the MoCA was indicative of lower scores on both outcomes. A low MoCA score within 1 week of stroke may indicate need for support or rehabilitation due to early impacts on personal activities of daily living, but is not associated with poor functional outcomes at 3 months.
Publisher: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 31-03-2020
Publisher: American Psychological Association (APA)
Date: 12-2020
DOI: 10.1037/PAS0000957
Publisher: Informa UK Limited
Date: 22-10-2016
Publisher: Informa UK Limited
Date: 09-2007
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.NEUROSCIENCE.2019.09.035
Abstract: Evidence suggests that cerebrovascular hemodynamic disturbances underlie cognitive deterioration secondary to cardiovascular disease (CVD), including manifestations other than stroke, but the mechanisms remain unclear. To date, the majority of studies have used neuropsychological measures validated for the detection of clinically significant cognitive decline but lack the sensitivity to accurately detect subclinical or subtle cognitive changes. The N2 and P3 components of the event-related potential are sensitive markers of attention and cognitive processing, and are valuable in the assessment of age-related cognitive changes and neurodegenerative disease. The aims of this study were to test (a) the sensitivity of N2 and P3 components in differentiating older adults with CVD from healthy controls, and (b) whether cerebrovascular hemodynamics are associated with alterations in attention in persons with non-stroke CVD. Older adults with CVD (n = 20) and healthy older adults (n = 20) without cognitive impairment or history of stroke and matched for age, were recruited. Cerebral blood flow velocity of the middle cerebral artery (MCAv) and Gosling's Pulsatility Index (PI) were assessed using Transcranial Doppler ultrasound (TCD). ERPs were elicited using a two-tone auditory oddball task. N2 litude was significantly reduced in the CVD group at midline frontal, central and parietal sites (p 0.6). No significant group differences were observed in N2 latency, P3 litude, or P3 latency. Further, MCAv and PI were strongly associated with N2 litude in the CVD group, such that greater MCAv was associated with reductions in N2 litude (b = -0.58, p = .018), whilst PI was associated with increases in N2 litude (b = 0.66, p = .006). No relationships between MCAv or PI with N2 or P3 ERP components were observed in the healthy control group. The data reported here suggest that a reduction in N2 litude may be an important objective indicator of subclinical cognitive and attentional alterations in non-stroke CVD, and support the notion that cerebrovascular hemodynamic disturbances play a role in the pathogenesis of cognitive deterioration secondary to non-stroke CVD.
Publisher: Springer Science and Business Media LLC
Date: 22-09-2017
Publisher: Wiley
Date: 07-2018
Publisher: Springer Science and Business Media LLC
Date: 07-11-2014
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.NEUROBIOLAGING.2017.03.028
Abstract: The apolipoprotein (APOE) ε4 allele and the Met variant of the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism are associated with reduced cognitive function in older adults. The aim of this study was to examine the independent and interactional effect of the APOE ε4 allele and BDNF Val66Met polymorphism on cognitive function in a cohort of healthy older adults who had undertaken further university level education. Multiple group latent growth curve modeling revealed no change in cognitive function over time in APOE ε4-carriers or in BDNF Met-carriers, nor in carriers of both APOE-ε4 and BDNF-Met alleles. Further, the results indicate that allelic variation in either APOE or BDNF does not modify the beneficial effects of a university-based education intervention on cognitive function over a 4-year period following the intervention.
Publisher: Cambridge University Press (CUP)
Date: 05-2012
DOI: 10.1017/S1041610212000695
Abstract: Background: Subjective memory complaints are a requirement in the diagnosis of mild cognitive impairment (MCI) as they are thought to indicate a decline in objective memory performance. However, recent research suggests that the relationship between subjective memory complaint and objective memory impairment is less clear. Thus, it is possible that many people without subjective memory complaints who develop Alzheimer's disease are precluded from a diagnosis of MCI. Methods: The present study examined the relationship between subjective memory complaint assessed using the Multifactorial Memory Questionnaire (MMQ) and objective memory impairment assessed using standard neuropsychological measures in cases of amnestic MCI ( n = 48), non-amnestic MCI ( n = 27), and unimpaired healthy participants ( n = 64). Results: Correlational and regression analyses indicated that subjective memory complaints displayed a poor relationship with objective memory performance. A subsequent discriminant function analysis indicated that subjective memory complaints failed to improve the diagnostic accuracy of MCI and resulted in increased rates of false negative and false positive diagnoses. Conclusion: The results of the present study suggest that a diagnostic criterion of subjective memory complaint reduces the accuracy of MCI diagnosis, resulting in an elevated rate of false positive and false negative diagnoses. The results of this study in conjunction with recent research indicate that a criterion of subjective memory complaint should be discarded from emerging diagnostic criteria for MCI.
Publisher: Elsevier BV
Date: 06-1997
Publisher: Public Library of Science (PLoS)
Date: 16-05-2019
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.NLM.2014.01.013
Abstract: Cognitive decline is a major factor in lowering the quality of life in older populations, and contributes substantially to social, economic, and health costs. As humans age, cognitive function decreases differentially, and in idual differences in cognitive ageing are likely attributed to a range of causes, including environmental and genetic influences. The current study included 360 participants (240 females and 120 males) aged between 50 and 79years from the Tasmanian Healthy Brain Project. The brain-derived neurotrophic factor (BDNF) Val66Met and Catechol-O-Methyltransferase (COMT) Val158Met polymorphisms were examined for their association with visual and auditory episodic memory performance. The polymorphisms were also investigated for their association with reported life-long engagement in complex cognitive activity using a retrospective questionnaire. Relative to the demographic variables, the gene variations were found to have no association with episodic memory performance, with the exception of the COMT polymorphism on a single measure of auditory memory (RAVLT). Several other studies also demonstrated that these polymorphisms have no, small, or inconsistent effects on memory function. The BDNF Val66Met and COMT Val158Met polymorphisms were also found to be of little significance to active engagement in complex cognitive activity throughout most of the lifespan. An association was detected between BDNF Val66Met and engagement in cognitive activity in early life (p=.04, d=.23), however this did not reach significance when adjusted for multiple comparisons. The biological mechanisms that underlie engagement in cognitive activity are elusive, thus the potential relationship between BDNF Val66Met genotype and early life cognitive engagement warrants further investigation.
Publisher: Springer Science and Business Media LLC
Date: 08-02-2019
Publisher: Wiley
Date: 07-2015
Publisher: Wiley
Date: 07-2015
Publisher: Wiley
Date: 2021
DOI: 10.1002/TRC2.12207
Abstract: Declining cognition in later life is associated with loss of independence and quality of life. This decline in cognition may potentially be reduced or reversed through engaging in cognitively stimulating activities. This study examined the potential for university attendance in later life to enhance cognitive function in older adults. Cognitively unimpaired adults (n = 485, 69% female, median age 60 years) were given the opportunity to undertake free university study. Repeated neurocognitive assessment was performed over 7 years. Participants in the university education group (n = 383) improved z = .02 SD (.01, .03) per year of the study compared to controls ( P = .001 averaged across a battery of cognitive tests). The largest improvements were observed on tests of language and verbal learning, memory, and episodic memory. Later‐life university study was associated with improved cognitive trajectories. Later‐life education may preserve cognitive function, specifically for functions associated with communication, social interaction, and maintaining independence.
Publisher: American Psychological Association (APA)
Date: 2000
Publisher: Elsevier BV
Date: 12-2023
Publisher: Hindawi Limited
Date: 2013
DOI: 10.1155/2013/437013
Abstract: Previous studies of mild cognitive impairment (MCI) have been criticised for using the same battery of neuropsychological tests during classification and longitudinal followup. The key concern is that there is a potential circularity when the same tests are used to identify MCI and then subsequently monitor change in function over time. The aim of the present study was to examine the evidence of this potential circularity problem. The present study assessed the memory function of 72 MCI participants and 50 healthy controls using an alternate battery of visual and verbal episodic memory tests 9 months following initial comprehensive screening assessment and MCI classification. In iduals who were classified as multiple-domain amnestic MCI (a-MCI+) at screening show a significantly reduced performance in visual and verbal memory function at followup using a completely different battery of valid and reliable tests. Consistent with their initial classification, those identified as nonamnestic MCI (na-MCI) or control at screening demonstrated the highest performance across the memory tasks. The results of the present study indicate that persistent memory deficits remain evident in amnestic MCI subgroups using alternate memory tests, suggesting that the concerns regarding potential circularity of logic may be overstated in MCI research.
Publisher: No publisher found
Date: 2000
Publisher: Informa UK Limited
Date: 28-02-2014
DOI: 10.1080/13803395.2014.890699
Abstract: Epidemiological research exploring risk factors for Alzheimer's dementia resulted in the identification of the mild cognitive impairment (MCI) profile. Subsequently, distinct subtypes of MCI have been proposed however, the validity of these as diagnostic entities remains uncertain. The aim of the present study was to examine the longitudinal neuropsychological profiles of MCI subtypes. A total of 118 adults aged 60-90 years were classified at screening as amnestic (a-MCI), nonamnestic (na-MCI), and multiple-domain amnestic (a-MCI+) and were assessed at two time points across 20 months on a comprehensive neuropsychological assessment battery. The a-MCI+ group displayed the poorest performance of all groups in terms of episodic memory, working memory, attention, and executive functioning. These findings suggest that the a-MCI+ subtype is the only variant that is recognizable via neuropsychological testing. In contrast, the differentiation between single-domain subtypes and healthy controls is difficult and may not be achievable through current neuropsychological assessment practices.
Publisher: Informa UK Limited
Date: 10-2016
DOI: 10.1111/AP.12178
Publisher: Elsevier BV
Date: 12-1995
Publisher: Wiley
Date: 07-2010
Publisher: Elsevier BV
Date: 03-2016
Publisher: SAGE Publications
Date: 31-01-2014
Abstract: The current study examined the measurement and structural invariance of the Depression Anxiety Stress Scales-21 (DASS-21) across ratings provided by men ( N = 227) and women ( N = 460). Multiple-group confirmatory factor analysis (CFA) supported full metric invariance and intercepts invariance for 20 of the 21 items. Invariance for all item intercepts was supported by multiple indicators multiple causes (MIMIC) procedure that controlled for the effects of age. Multiple-group CFA supported invariance for all factor variances and covariances. This procedure and the MIMIC analyses found equivalency for all latent mean scores. These findings indicate good support for measurement and structural invariance of the DASS-21 rating across men and women. The psychometric and practical implications of the findings are discussed.
Publisher: American Psychological Association (APA)
Date: 2015
DOI: 10.1037/NEU0000249
Abstract: Increasing an in idual's level of cognitive reserve (CR) has been suggested as a nonpharmacological approach to reducing the risk for Alzheimer's disease. We examined changes in CR in older adults participating over 4 years in the Tasmanian Healthy Brain Project. A s le of 459 healthy older adults between 50 and 79 years of age underwent a comprehensive annual assessment of current CR, neuropsychological function, and psychosocial factors over a 4-year period. The intervention group of 359 older adults (M = 59.61 years, SD = 6.67) having completed a minimum of 12 months part-time university study were compared against a control reference group of 100 adults (M = 62.49 years, SD = 6.24) who did not engage in further education. Growth mixture modeling demonstrated that 44.3% of the control s le showed no change in CR, whereas 92.5% of the further education participants displayed a significant linear increase in CR over the 4 years of the study. These results indicate that older adults engaging in high-level mental stimulation display an increase in CR over a 4-year period. Increasing mental activity in older adulthood may be a viable strategy to improve cognitive function and offset cognitive decline associated with normal aging. (PsycINFO Database Record
Publisher: Wiley
Date: 18-09-2017
Publisher: Informa UK Limited
Date: 03-03-2011
Publisher: American Psychological Association (APA)
Date: 03-2011
DOI: 10.1037/A0021134
Abstract: Mild cognitive impairment (MCI) has emerged as a classification for a prodromal phase of cognitive decline that may precede the emergence of Alzheimer's disease (AD). Recent research suggests that attention, executive, and working memory deficits may appear much earlier in the progression of AD than traditionally conceptualized, and may be more consistently associated with the later development of AD than memory processing deficits. The present study longitudinally tracked attention, executive and working memory functions in subtypes of MCI. In a longitudinal study, 52 amnestic MCI (a-MCI), 29 nonamnestic MCI (na-MCI), and 25 age- and education-matched controls undertook neuropsychological assessment of visual and verbal memory, attentional processing, executive functioning, working memory capacity, and semantic language at 10 month intervals. Analysis by repeated measures ANOVA indicate that the a-MCI and na-MCI groups displayed a decline in simple sustained attention (ηp² = .054) with a significant decline on a task of ided attention (ηp² = .053) being evident in the a-MCI group. Stable deficits were found on other measures of attention, working memory and executive function in the a-MCI and na-MCI groups. The a-MCI group displayed stable impairments to visual and verbal memory. The results indicate that a-MCI and na-MCI display a stable pattern of deficits to attention, working memory, and executive function. The decline in simple sustained attention in a-MCI and n-MCI groups and to ided attention in a-MCI may be early indicators of possible transition to dementia from MCI. However, further research is required to determine this.
Publisher: Elsevier BV
Date: 02-2017
Publisher: Informa UK Limited
Date: 22-02-2016
DOI: 10.1080/13803395.2015.1137557
Abstract: There is evidence that the e4 allele of the apolipoprotein E (APOE) gene is detrimental to cognitive function, but results from traumatic brain injury (TBI) populations are mixed. A possible explanation is that APOEe2 carriers have routinely been incorporated into APOEe4 and non-e4 groups, despite APOEe2 being proposed to have an ameliorative effect. Our primary aim was to investigate the influence of APOEe4 on cognitive impairment during early recovery following TBI, excluding the potential confound of APOEe2 possession. A secondary objective was to explore whether APOEe4 displays more pronounced effects in moderate to severe TBI and to consider the potential postinjury protective influence of the APOEe2 allele. Participants who recently sustained a TBI (posttraumatic amnesia > 5 minutes) were assessed on measures of information processing speed, executive function, and working memory upon remission of posttraumatic amnesia. APOE genotype was determined by buccal saliva DNA extraction (APOEe4 n = 37, APOEe3 n = 92, APOEe2 n = 13). Stepwise multiple regressions were performed to compare APOEe4 carriers to APOEe3 homozygotes, with injury severity, age, and estimated premorbid IQ included in the first step. This model was found to significantly predict performance on all tasks, accounting for 17.3-24.3% of the variance. When APOEe4 status was added for the second step, there were no significant changes on any tasks (additional variance <1%). The effect of APOEe4 in moderate to severe TBI and the effect of APOEe2 were explored by analysis of covariance (ANCOVA), with no significant effects revealed. It is unlikely that APOE genotype influences cognitive function in the initial recovery period following TBI, regardless of injury severity. However, a more nuanced and long-term exploration of the effect of APOE genotype in the TBI population is warranted.
Publisher: Elsevier BV
Date: 05-2003
Publisher: Wiley
Date: 07-2011
Publisher: Wiley
Date: 07-2012
Publisher: Wiley
Date: 07-2015
Publisher: SAGE Publications
Date: 02-01-2017
Abstract: Cognitive reserve (CR) is a theoretical construct describing the underlying cognitive capacity of an in idual that confers differential levels of resistance to, and recovery from, brain injuries of various types. To date, estimates of an in idual's level of CR have been based on single proxy measures that are retrospective and static in nature. To develop a measure of dynamic change in CR across a lifetime, we previously identified a latent factor, derived from an exploratory factor analysis of a large s le of healthy older adults, as current CR (cCR). In the present study, we examined the longitudinal results of a s le of 272 older adults enrolled in the Tasmanian Healthy Brain Project. Using results from 12-month and 24-month reassessments, we examined the longitudinal validity of the cCR factor using confirmatory factor analyses. The results of these analyses indicate that the cCR factor structure is longitudinally stable. These results, in conjunction with recent results from our group demonstrating dynamic increases in cCR over time in older adults undertaking further education, lend weight to this cCR measure being a valid estimate of dynamic change in CR over time.
Publisher: Wiley
Date: 2018
Publisher: Wiley
Date: 12-2020
DOI: 10.1002/ALZ.044170
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-01-2023
DOI: 10.1212/WNL.0000000000201369
Abstract: Females have a higher age-adjusted incidence of Alzheimer disease than males but the reasons for this remain unclear. One proposed contributing factor is that, historically, females had less access to education and, therefore, may accumulate less cognitive reserve. However, educational attainment is confounded by IQ, which in itself is a component of cognitive reserve and does not differ between sexes. Steeper age-related cognitive declines are associated with increased risk of dementia. We, therefore, evaluated the moderating effects of 2 proxies for cognitive reserve, education and IQ, on the steepness of age-related declining cognitive trajectories in unimpaired older males and females. The Tasmanian Healthy Brain Project, a long-term cohort study, recruited healthy Australians aged 50–80 years without cognitive impairment. Baseline cognitive reserve was measured using educational history and IQ, measured by the Wechsler Test of Adult Reading, Full Scale Predicted IQ (WTAR-FSIQ). Cognitive trajectories for language, executive function, and episodic and working memory over 5 years were extracted from neuropsychological assessments. The adjusted effects of education, estimated IQ, and APOE allelic variant on cognitive trajectories were compared between males and females. Five hundred sixty-two in iduals (mean [SD] age 60 [6.7] years 68% male 33% APOE ε4+) were followed up over 5 years with 1,924 assessments and 24,946 cognitive test scores (annualized attrition rate 6.6% per year). Estimated IQ correlated with years of education ( p 0.001). Estimated IQ interacted with sex to moderate age-related cognitive trajectories ( p = 0.03 adjusted for education) lower IQ males experienced steeper declining trajectories than higher IQ males, but lower IQ females had similar steepness of declining trajectories to higher IQ females. Education was not associated with rate of cognitive decline ( p = 0.67 adjusted for WTAR-FSIQ). There were no significant differences in age-related cognitive trajectories between APOE genotypes in either sex. IQ, a measure of cognitive reserve, predicted the steepness of declining cognitive trajectories in males only. Education did not explain as much variation in cognitive trajectories as IQ. Our findings do not support the hypothesis that historical sex disparities in access to education contribute to the higher female incidence of Alzheimer disease.
Publisher: SERDI
Date: 2019
Abstract: In 358 participants of the Tasmanian Healthy Brain Project, we quantified the cognitive consequences of engaging in varying loads of university-level education in later life, and investigated whether or not BDNF Val66Met affected outcomes. Assessment of neuropsychological, health, and psychosocial function was undertaken at baseline, 12-month, and 24-month follow-up. Education load was positively associated with change in language processing performance, but this effect did not reach statistical significance (P = 0.064). The BDNF Val66Met polymorphism significantly moderated the extent to which education load was associated with improved language processing (P = 0.026), with education load having a significant positive relationship with cognitive change in BDNF Met carriers but not in BDNF Val homozygotes. In older adults who carry BDNF Met, engaging in university-level education improves language processing performance in a load-dependent manner.
Publisher: Cambridge University Press (CUP)
Date: 23-04-2014
DOI: 10.1017/BRIMP.2014.2
Abstract: There is compelling evidence that traditional methods used to address the detrimental impacts of missing data are inadequate. Despite this, researchers have been slow to utilise newer statistical approaches known to be more effective. The aim of the current article is to offer a conceptual explanation of the rationale for using newer missing data techniques, with a focus on multiple imputation (MI). To illustrate the relative efficacy of deletion, single imputation and multiple imputation techniques in the clinical setting, 20 cases were selected randomly from a population study investigating the cognitive sequelae of traumatic brain injury (TBI), and 8 out of 20 cases had scores on one variable deleted to simulate a missing data set. Comparing the parameter estimates obtained by each technique to the known parameters of the complete data set revealed that MI outperformed deletion and single imputation approaches. It is therefore recommended that more sophisticated techniques such as MI should be considered in clinical research.
Publisher: Frontiers Media SA
Date: 08-10-2014
Publisher: Public Library of Science (PLoS)
Date: 13-05-2022
DOI: 10.1371/JOURNAL.PONE.0268379
Abstract: Clinical and biochemical ersity of Parkinson’s disease (PD) and numerous demographic, clinical, and pathological measures influencing cognitive function and its decline in PD create problems with the determination of effects of in idual measures on cognition in PD. This is particularly the case where these measures significantly interrelate with each other producing intricate networks of direct and indirect effects on cognition. Here, we use generalized structural equation modelling (GSEM) to identify and characterize significant paths for direct and indirect effects of 14 baseline measures on global cognition in PD at baseline and at 4 years later. We consider 269 drug-naïve participants from the Parkinson’s Progression Marker Initiative database, diagnosed with idiopathic PD and observed for at least 4 years after baseline. Two GSEM networks are derived, highlighting the possibility of at least two different molecular pathways or two different PD sub-types, with either CSF p-tau181 or amyloid beta (1–42) being the primary protein variables potentially driving progression of cognitive decline. The models provide insights into the interrelations between the 14 baseline variables, and determined their total effects on cognition in early PD. High CSF amyloid concentrations ( 500 pg/ml) are associated with nearly full protection against cognitive decline in early PD in the whole range of baseline age between 40 and 80 years, and irrespectively of whether p-tau181 or amyloid beta (1–42) are considered as the primary protein variables. The total effect of depression on cognition is shown to be strongly lified by PD, but not at the time of diagnosis or at prodromal stages. CSF p-tau181 protein could not be a reliable indicator of cognitive decline because of its significantly heterogeneous effects on cognition. The outcomes will enable better understanding of the roles of the clinical and pathological measures and their mutual effects on cognition in early PD.
Publisher: American Psychological Association (APA)
Date: 07-2012
DOI: 10.1037/A0028576
Abstract: Studies of Mild Cognitive Impairment (MCI) show elevated rates of conversion to dementia at the group level. However, previous studies of the trajectory of MCI identify great heterogeneity of outcomes, with a significant proportion of in iduals with MCI remaining stable over time, changing MCI subtype classification, or reverting to a normal cognitive state at long-term follow-up. The present study examined in idual outcomes at 20 months in a group of older adults classified according to MCI subtypes. A total of 106 participants, 81 with different subtypes of MCI and 25 healthy controls, undertook longitudinal neuropsychological assessment of visual and verbal memory, attentional processing, executive functions, working memory capacity, and semantic memory. At 20 months 12.3% of the MCI group progressed to dementia, 62.9% continued to meet MCI criteria, and 24.7% reverted to unimpaired levels of function. A discriminant function analysis predicted outcome at 20 months on the basis of baseline neuropsychological test performance with 86.3% accuracy. The analysis indicated that a pattern of impairments on visual episodic memory, verbal episodic memory, short-term memory, working memory, and attentional processing differentiated between participants who developed dementia, recovered from MCI, or remained in stable MCI. The results of the present study raise questions regarding the specificity of existing criteria for the subtypes of MCI, with these results indicating a high degree of instability in classification over time. In addition, the results suggest that multidomain MCI is the most reliable precursor stage to the development of AD.
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.BBR.2014.06.022
Abstract: Genetic polymorphisms of apolipoprotein E (APOE) and brain-derived neurotrophic factor (BDNF) have shown inconsistent associations with healthy adult cognitive functions. Recent investigations have suggested that APOE polymorphisms do not contribute to non-pathological cognitive function and that any effect is likely due to prodromal Alzheimer's disease (AD). Similarly, although BDNF Val66Met polymorphisms affect hippoc al morphology and function, associations with learning and/or memory have not always been found. This study sought to determine whether APOE and BDNF polymorphisms were associated, either independently or in combination, with adult cognition. Comprehensive neuropsychological assessments were conducted on 433 older adults, aged 50-79 years (M=62.16, SD=6.81), which yielded measures of episodic memory, working memory, executive function, and language processing. Participants underwent comprehensive neuropsychological assessment to ensure that only cognitively intact in iduals comprised the s le. APOE and BDNF polymorphic data were used as predictors in general linear models that assessed composite cognitive domain variables, while covarying for education and age. Although no main effects for APOE or BDNF were found, the analysis identified a significant APOE×BDNF interaction that predicted episodic memory performance (p=.02, η(2)=.02). Post-hoc analyses demonstrated that in BDNF Val homozygotes, the cognitive consequences of APOE polymorphisms were minimal. However, in BDNF Met carriers, the hypothesized beneficial/detrimental effects of APOE polymorphisms were found. Our data show that concurrent consideration of both APOE and BDNF polymorphisms are required in order to witness a cognitive effect in healthy older adults.
Publisher: Springer Science and Business Media LLC
Date: 06-06-2017
DOI: 10.1038/TP.2017.107
Publisher: Wiley
Date: 07-2013
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.JSTROKECEREBROVASDIS.2022.106614
Abstract: Cognitive impairment is common and problematic post-stroke, yet vital information to understand early cognitive recovery is lacking. To examine early cognitive recovery, it is first necessary to establish the feasibility of repeat cognitive assessment during the acute post-stroke phase. To determine if serial computerised testing is feasible for cognitive assessment in an acute post-stroke phase, measured by assessment completion rates. An observational cohort study recruited consecutive stroke patients admitted to an acute stroke unit within 48 hours of onset. Daily assessment with the Cambridge Neuropsychological Test Automated Battery (CANTAB) was performed for seven days, and single Montreal Cognitive Assessment (MoCA). Seventy-one participants were recruited, mean age 74 years, with 67 completing daily testing. Participants had predominantly mild (85% NIHSS ≤6), ischemic (90%) stroke, 32% demonstrated clinical delirium. The first day of testing, 76% of participants completed CANTAB batteries. Eighty-seven percent of participants completed MoCA a mean of 3.4 days post-stroke. The proportion of CANTAB batteries completed improved significantly from day 2 to day 3 post-stroke with test completion rates stabilizing ≥ 92% by day 4. Participants with incomplete CANTAB were older, with persisting delirium, and longer stay in acute care. Serial computerised cognitive assessments are feasible the first week post-stroke and provide a novel approach to measuring cognitive change for both clinical and research purposes. Maximum completion rates by day four have clinical implications for optimal timing of cognitive testing.
Publisher: Frontiers Media SA
Date: 02-08-2021
DOI: 10.3389/FNAGI.2021.725914
Abstract: Background : The brain-derived neurotrophic factor (BDNF) protein has been shown to have a prominent role in neuron survival, growth, and function in experimental models, and the BDNF Val66Met polymorphism which regulates its expression has been linked to resilience toward the effects of aging on cognition. Cognitively stimulating activity is linked to both increased levels of BDNF in the brain, and protection against age-related cognitive decline. The aim of this study was to investigate the associations between serum BDNF levels, the BDNF Val66Met genotype, and components of cognitive reserve in early and mid-life, measured with the Lifetime of Experiences Questionnaire (LEQ). Methods : Serum BDNF levels were measured cross-sectionally in 156 participants from the Tasmanian Healthy Brain Project (THBP) cohort, a study examining the potential benefits of older adults engaging in a university-level education intervention. Multiple linear regression was used to estimate serum BDNF’s association with age, education, gender, BDNF Val66Met genotype, later-life university-level study, and cognitively stimulating activities measured by the LEQ. Results : Serum BDNF in older adults was associated with early life education and training, increasing 0.007 log(pg/ml) [95%CI 0.001, 0.012] per unit on the LEQ subscale. Conversely, education and training in mid-life were associated with a −0.007 log(pg/ml) [−0.012, −0.001] decrease per unit on the LEQ subscale. Serum BDNF decreased with age (−0.008 log(pg/ml) [−0.015, −0.001] per year), and male gender (−0.109 log(pg/ml) [−0.203, −0.015]), but mean differences between the BDNF Val66Met polymorphisms were not significant ( p = 0.066). All effect sizes were small, with mid-life education and training having the largest effect size ( η p 2 = 0.044). Conclusion : Education in both early and mid-life explained small but significant amounts of variance in serum BDNF levels, more than age or gender. These effects were opposed and independent, suggesting that education at different stages of life may be associated with different cognitive and neural demands. Education at different stages of life may be important covariates when estimating associations between other exposures and serum BDNF.
Publisher: SAGE Publications
Date: 24-09-2016
Abstract: In the present study, we examined the effect of working while seated, while standing, or while walking on measures of short-term memory, working memory, selective and sustained attention, and information-processing speed. The advent of computer-based technology has revolutionized the adult workplace, such that average adult full-time employees spend the majority of their working day seated. Prolonged sitting is associated with increasing obesity and chronic health conditions in children and adults. One possible intervention to reduce the negative health impacts of the modern office environment involves modifying the workplace to increase incidental activity and exercise during the workday. Although modifications, such as sit-stand desks, have been shown to improve physiological function, there is mixed information regarding the impact of such office modification on in idual cognitive performance and thereby the efficiency of the work environment. In a fully counterbalanced randomized control trial, we assessed the cognitive performance of 45 undergraduate students for up to a 1-hr period in each condition. The results indicate that there is no significant change in the measures used to assess cognitive performance associated with working while seated, while standing, or while walking at low intensity. These results indicate that cognitive performance is not degraded with short-term use of alternate workstations.
Publisher: Wiley
Date: 07-2012
Publisher: Elsevier BV
Date: 10-2002
Publisher: Wiley
Date: 26-12-2014
DOI: 10.1111/ENE.12333
Abstract: Previous research examining mild cognitive impairment (MCI) has highlighted the heterogeneity of outcome in MCI sufferers. MCI is associated with greater risk of progression to dementia however, a substantial proportion of those identified with MCI have alternative outcomes including recovery to unimpaired status. This heterogeneity may in part reflect insufficient sensitivity and specificity in identifying subclinical memory impairment. The present study examined learning in a s le of 109 adults aged 61-91 years with persistent amnestic MCI, persistent non-amnestic MCI, recovered MCI and healthy controls. At the final assessment point, learning for words recalled across each trial of the Rey Auditory Verbal Learning Test was examined for each group. It was found that persistent amnestic MCI participants displayed significantly lower learning compared with recovered MCI and healthy control groups. The results of this study indicated that poor learning across trials may be a defining feature of persistent amnestic MCI. Further research is required to establish the predictive utility of within trial list learning performance to identify in iduals with persistent and progressive variants of MCI.
Publisher: American Psychological Association (APA)
Date: 10-2016
DOI: 10.1037/NEU0000270
Publisher: Wiley
Date: 16-02-2014
DOI: 10.1111/PSYG.12042
Abstract: Research suggests that working memory and attention deficits may be present in mild cognitive impairment (MCI). However, the functional status of these domains within revised MCI subtypes remains unclear, particularly because previous studies have examined these cognitive domains with the same tests that were used to classify MCI subtypes. The aim of this study was to examine working memory and attention function in MCI subtypes on a battery of neuropsychological tests that were distinct from those used to classify MCI subtypes A total of 122 adults aged 60-90 years were classified at baseline as amnestic MCI, non-amnestic MCI, and multi-domain amnestic (a-MCI+). The attentional and working memory capacity of participants was examined using a battery of tests distinct from those used to classify MCI at screening. The a-MCI+ group demonstrated the poorest performance on all working memory tasks and specific sub-processes of attention. The non-amnestic MCI group had lowered performance on visual span and complex sustained attention only. There was no evidence of either attentional or working memory impairment in the amnestic MCI participants. When MCI cohorts are assessed on measures distinct from those used at classification, a-MCI+ subjects had the most compromised working memory and attention function. These results support previous findings that suggest a-MCI+ more closely resembles early stage Alzheimer's disease and those with a-MCI+ may be at increased rate of future cognitive decline compared to those with other MCI subtypes.
Start Date: 2016
End Date: 2020
Funder: Research Executive Agency
View Funded ActivityStart Date: 2016
End Date: 2020
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2011
End Date: 2016
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2016
End Date: 2019
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2002
End Date: 2002
Funder: University of Tasmania
View Funded ActivityStart Date: 2004
End Date: 2007
Funder: Australian Research Council
View Funded ActivityStart Date: 2004
End Date: 06-2008
Amount: $200,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2004
End Date: 12-2008
Amount: $115,180.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2009
End Date: 07-2013
Amount: $139,142.00
Funder: Australian Research Council
View Funded Activity