ORCID Profile
0000-0002-2103-7748
Current Organisations
University of the Sunshine Coast
,
University of New South Wales
,
Neuroscience Research Australia
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Biological Psychology (Neuropsychology, Psychopharmacology, Physiological Psychology) | Psychology
Behaviour and Health | Expanding Knowledge in Psychology and Cognitive Sciences |
Publisher: Frontiers Media SA
Date: 16-06-2021
DOI: 10.3389/FNHUM.2021.661079
Abstract: High-intensity exercise has enhanced motor learning in healthy young adults. Anodal-transcranial direct current stimulation (a-tDCS) may optimize these effects. This study aimed to determine the effects of a short-term high-intensity interval exercise intervention either with or without a-tDCS on the learning and retention of a novel motor task in middle-aged adults. Forty-two healthy middle-aged adults (age = 44.6 ± 6.3, female = 76%) were randomized into three groups: exercise and active a-tDCS, exercise and sham a-tDCS, and a non-exercise and sham a-tDCS control. Participants completed a baseline testing session, followed by three intervention sessions 48-h apart. The exercise groups completed 20-min of high-intensity exercise followed by a novel sequential visual isometric pinch task (SVIPT) while receiving 20-min of 1.5 mA a-tDCS, or sham tDCS. The control group completed 20-min of reading before receiving sham a-tDCS during the SVIPT. Learning was assessed by skill change within and between intervention sessions. Participants returned 5–7 days after the final intervention session and performed the SVIPT task to assess retention. All three groups showed evidence of learning on the SVIPT task. Neither group displayed enhanced overall learning or retention when compared to the control group. High-intensity exercise with or without a-tDCS did not improve learning or retention of a novel motor task in middle-aged adults. The methodological framework provides direction for future research to investigate the potential of differing exercise intensity effects on learning and retention.
Publisher: Wiley
Date: 12-02-2021
DOI: 10.1002/MDC3.13147
Abstract: Apathy is a disorder of motivation common to Huntington's disease (HD). Recent conceptual frameworks suggest that apathy is not unitary but consists of discrete subtypes (“dimensions”). Which of the proposed dimensions are preferentially affected in HD, and how these dimensions evolve with disease progression is unknown. The Dimensional Apathy Scale (DAS) separates apathy into Executive, Initiation and Emotional subscales. Using the DAS, we aimed to: 1) Determine the apathy subtypes prevalent in HD 2) Compare the DAS against a unitary measure of apathy (Apathy Evaluation Scale, AES) 3) Assess the reliability of self‐ and observer‐ratings and 4) Determine the relationship between the DAS, and disease burden, total functional capacity (TFC) and the AES. Fifty pre‐manifest, 51 manifest‐HD, 87 controls, and 50 HD‐observers completed the DAS, AES, and TFC. Manifest‐HD participants had the highest levels of apathy across all dimensions (30.4% on Executive subscale, 34.8% on Initiation subscale, and 15.2% on Emotional subscale), relative to pre‐manifest and control participants. Self‐ and observer‐ratings on the DAS did not differ. Hierarchical regressions across the entire gene‐expanded s le showed that scores on the Initiation subscale correlated with AES scores higher Executive subscale scores were related to higher disease burden and Emotional subscale scores with lower total functional capacity. In this first study of the DAS in HD, manifest‐HD participants were more apathetic than pre‐manifest and control participants across all apathy subtypes. The DAS may be a useful tool for measuring different aspects of apathy in people with HD.
Publisher: American Psychological Association (APA)
Date: 02-2018
DOI: 10.1037/NEU0000400
Abstract: The authors tested the hypothesis that Parkinson's disease (PD) participants would perform better in an emotion recognition task with dynamic (video) stimuli compared to a task using only static (photograph) stimuli and compared performances on both tasks to healthy control participants. In a within-subjects study, 21 PD participants and 20 age-matched healthy controls performed both static and dynamic emotion recognition tasks. The authors used a 2-way analysis of variance (controlling for in idual participant variance) to determine the effect of group (PD, control) on emotion recognition performance in static and dynamic facial recognition tasks. Groups did not significantly differ in their performances on the static and dynamic tasks however, the trend was suggestive that PD participants performed worse than controls. PD participants may have subtle emotion recognition deficits that are not ameliorated by the addition of contextual cues, similar to those found in everyday scenarios. Consistent with previous literature, the results suggest that PD participants may have underlying emotion recognition deficits, which may impact their social functioning. (PsycINFO Database Record
Publisher: American Psychological Association (APA)
Date: 03-2017
DOI: 10.1037/NEU0000323
Abstract: Emotion processing abilities might be reduced in amyotrophic lateral sclerosis (ALS). Previous studies of emotion processing in ALS have inconsistent results, and are limited by variations in task difficulty, modalities examined, and participants' cognitive status. The current study used a battery of emotion processing tasks at differing levels of difficulty and across different modalities (facial affect and voice prosody) to assess the extent of emotion processing deficits in nondemented ALS. 33 ALS participants with intact basic cognition and 22 healthy controls completed the abbreviated Comprehensive Affect Testing System (CATS), which assesses simple and complex facial affect recognition, affective prosody recognition, cross-modal face-prosody integration, and semantic comprehension of affect. Participants also completed measures of executive function, mood, and functional impairment. ALS participants showed impairments on complex facial affect recognition, affective prosody recognition, and cross-modal integration. In contrast, simple facial affect recognition and semantic comprehension of affect were intact. ALS participants did not have significant mood symptoms, and neither mood nor functional impairment was related to emotion processing. Performance on the cross-modal composite was related to executive function, however, this relationship was not apparent for facial or prosody recognition within a single modality. These results indicate that people living with ALS without dementia often have subtle difficulties with recognizing emotions in both faces and voices, even in the context of intact basic cognition. Clinicians should be aware of the potential for these emotion processing difficulties to be present in ALS and to affect interpersonal behavior and quality of life. (PsycINFO Database Record
Publisher: Wiley
Date: 30-06-2017
Abstract: Speech and language impairments are well-established in in iduals with amyotrophic lateral sclerosis (ALS). However, knowledge about particular aspects of social communication and everyday conversational abilities is limited. To investigate self- and informant-report ratings of social communicative abilities in ALS participants and matched healthy controls. Thirty-two participants with ALS and 24 controls completed the La Trobe Communication Questionnaire (LCQ). Participants nominated a close other to provide an informant report on the LCQ. Demographic and clinical information was also collected. Informant ratings indicated greater difficulties in conversational initiation, effectiveness and partner sensitivity for ALS participants compared with controls. ALS participants did not rate their social communicative abilities as poorer than controls and self-reports only differed from informant ratings in the control group. LCQ scores were not significantly correlated with clinical/functional variables. Social communication can be reduced in ALS and in iduals may lack insight into these difficulties. In order to understand and provide targeted interventions for such difficulties, clinical speech and language assessment should incorporate social communication assessment, including both a self- and informant-report format.
Publisher: Cambridge University Press (CUP)
Date: 17-02-2021
DOI: 10.1017/S0033291720000094
Abstract: Cognitive impairment is a core feature of Huntington's disease (HD), however, the onset and rate of cognitive decline is highly variable. Apathy is the most common neuropsychiatric symptom of HD, and is associated with cognitive impairment. The aim of this study was to investigate apathy as a predictor of subsequent cognitive decline over 2 years in premanifest and early HD, using a prospective, longitudinal design. A total of 118 premanifest HD gene carriers, 111 early HD and 118 healthy control participants from the multi-centre TRACK-HD study were included. Apathy symptoms were assessed at baseline using the apathy severity rating from the Short Problem Behaviours Assessment. A composite of 12 outcome measures from nine cognitive tasks was used to assess cognitive function at baseline and after 24 months. In the premanifest group, after controlling for age, depression and motor signs, more apathy symptoms predicted faster cognitive decline over 2 years. In contrast, in the early HD group, more motor signs, but not apathy, predicted faster subsequent cognitive decline. In the control group, only older age predicted cognitive decline. Our findings indicate that in premanifest HD, apathy is a harbinger for cognitive decline. In contrast, after motor onset, in early diagnosed HD, motor symptom severity more strongly predicts the rate of cognitive decline.
Publisher: Elsevier BV
Date: 04-2011
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.CORTEX.2018.05.019
Abstract: Huntington's disease (HD) is a neurodegenerative disorder associated with impaired facial emotion recognition and altered subjective experience of emotion. These impairments likely result from the effects of the disease on underlying neurobiological mechanisms. Studies using self-report to examine emotional experiences have been ambiguous regarding whether experiences are diminished or exaggerated, possibly due to cognitive impairment and lack of insight in HD. To infer affective states more objectively and overcome the limitations of self-report, we used facial EMG to measure muscle responses to emotionally-evocative scenes. Further, we examined muscle responses to emotionally-expressive faces, because facial mimicry is thought to facilitate emotion recognition and social affiliation. Twenty-three HD participants (late pre-manifest and early symptomatic) were compared to twenty-five healthy controls in a scene condition and a face condition. EMG activity was measured from facial muscles associated with expressing particular emotions: 1) corrugator supercilii for anger, 2) frontalis for fear, 3) levator labii for disgust, and 4) both zygomaticus major and orbicularis oculi for happiness. Compared to controls, HD participants showed diminished responses to disgusting scenes, and to happy and fearful faces. Our findings provide evidence for a loss of disgust experience in HD. Further, consistent with the alleged affiliative function of facial mimicry, diminished mimicry responses may be relevant to social-emotional changes in HD. Our findings help understand the neural mechanisms underlying emotion processing impairments in HD.
Publisher: Oxford University Press (OUP)
Date: 05-2019
Abstract: A single bout of cardiovascular exercise can enhance plasticity in human cortex however, the intensity required for optimal enhancement is debated. We investigated the effect of exercise intensity on motor cortex synaptic plasticity, using transcranial magnetic stimulation. Twenty healthy adults (Mage = 35.10 ± 13.25 years) completed three sessions. Measures of cortico-motor excitability (CME) and inhibition were obtained before and after a 20-min bout of either high-intensity interval exercise, moderate-intensity continuous exercise, or rest, and again after intermittent theta burst stimulation (iTBS). Results showed that high-intensity interval exercise enhanced iTBS plasticity more than rest, evidenced by increased CME and intracortical facilitation, and reduced intracortical inhibition. In comparison, the effect of moderate-intensity exercise was intermediate between high-intensity exercise and rest. Importantly, analysis of each participant’s plasticity response profile indicated that high-intensity exercise increased the likelihood of a facilitatory response to iTBS. We also established that the brain-derived neurotrophic factor Val66Met polymorphism attenuated plasticity responses following high-intensity exercise. These findings suggest that high-intensity interval exercise should be considered not only when planning exercise interventions designed to enhance neuroplasticity, but also to maximize the therapeutic potential of non-invasive brain stimulation. Additionally, genetic profiling may enhance efficacy of exercise interventions for brain health.
Publisher: Frontiers Media SA
Date: 08-03-2023
DOI: 10.3389/FPSYG.2023.1089333
Abstract: Cardiorespiratory exercise has emerged as a promising candidate to modify disease progression in Huntington’s disease (HD). In animal models, exercise has been found to alter biomarkers of neuroplasticity and delay evidence of disease, and some interventions–including exercise–have shown benefits in human HD patients. In healthy human populations, increasing evidence suggests that even a single bout of exercise can improve motor learning. In this pilot study, we investigated the effect of a single bout of moderate intensity aerobic exercise on motor skill learning in presymptomatic and early manifest HD patients. Participants were allocated to either an exercise ( n = 10) or control ( n = 10) group. They performed either 20 min of moderate intensity cycling or rest before practicing a novel motor task, the sequential visual isometric pinch force task (SVIPT). After 1 week, the retention of the SVIPT was measured in both groups. We found that the exercise group performed significantly better during initial task acquisition. There were no significant differences in offline memory consolidation between groups, but total skill gain across both acquisition and retention sessions was greater in the group who exercised. The better performance of the exercise group was driven by improvements in accuracy, rather than speed. We have shown that a single bout of moderate intensity aerobic exercise can facilitate motor skill learning in people with HD gene-expansion. More research is needed to investigate the underlying neural mechanisms and to further explore the potential for neurocognitive and functional benefits of exercise for people with HD.
Publisher: Oxford University Press (OUP)
Date: 19-06-2019
DOI: 10.1093/BRAIN/AWZ115
Abstract: The mismatch repair gene MSH3 has been implicated as a genetic modifier of the CAG·CTG repeat expansion disorders Huntington’s disease and myotonic dystrophy type 1. A recent Huntington’s disease genome-wide association study found rs557874766, an imputed single nucleotide polymorphism located within a polymorphic 9 bp tandem repeat in MSH3/DHFR, as the variant most significantly associated with progression in Huntington’s disease. Using Illumina sequencing in Huntington’s disease and myotonic dystrophy type 1 subjects, we show that rs557874766 is an alignment artefact, the minor allele for which corresponds to a three-repeat allele in MSH3 exon 1 that is associated with a reduced rate of somatic CAG·CTG expansion (P = 0.004) and delayed disease onset (P = 0.003) in both Huntington’s disease and myotonic dystrophy type 1, and slower progression (P = 3.86 × 10−7) in Huntington’s disease. RNA-Seq of whole blood in the Huntington’s disease subjects found that repeat variants are associated with MSH3 and DHFR expression. A transcriptome-wide association study in the Huntington’s disease cohort found increased MSH3 and DHFR expression are associated with disease progression. These results suggest that variation in the MSH3 exon 1 repeat region influences somatic expansion and disease phenotype in Huntington’s disease and myotonic dystrophy type 1, and suggests a common DNA repair mechanism operates in both repeat expansion diseases.
Publisher: Springer Science and Business Media LLC
Date: 20-01-2022
DOI: 10.1038/S41598-021-04378-2
Abstract: Huntington’s disease (HD) mouse models suggest that cardiovascular exercise may enhance neuroplasticity and delay disease signs, however, the effects of exercise on neuroplasticity in people with HD are unknown. Using a repeated-measures experimental design, we compared the effects of a single bout of high-intensity exercise, moderate-intensity exercise, or rest, on motor cortex synaptic plasticity in 14 HD CAG-expanded participants (9 premanifest and 5 early manifest) and 20 CAG-healthy control participants, using transcranial magnetic stimulation. Measures of cortico-motor excitability, short-interval intracortical inhibition and intracortical facilitation were obtained before and after a 20-min bout of either high-intensity interval exercise, moderate-intensity continuous exercise, or rest, and again after intermittent theta burst stimulation (iTBS). HD participants showed less inhibition at baseline compared to controls. Whereas the control group showed increased excitability and facilitation following high-intensity exercise and iTBS, the HD group showed no differences in neuroplasticity responses following either exercise intensity or rest, with follow-up Bayesian analyses providing consistent evidence that these effects were absent in the HD group. These findings indicate that exercise-induced synaptic plasticity mechanisms in response to acute exercise may be attenuated in HD, and demonstrate the need for future research to further investigate exercise and plasticity mechanisms in people with HD.
Publisher: Future Medicine Ltd
Date: 04-2015
DOI: 10.2217/NMT.14.58
Abstract: SUMMARY In Huntington's disease (HD), there is growing evidence of neural compensation during neurodegeneration, and that these processes might be modifiable by environmental factors. Cognitive intervention to improve brain function has been trialled only to a very limited extent in HD however, it has shown promise in other neurodegenerative diseases. In this review, we discuss the evidence for the use of cognitive intervention to boost neural compensation in HD, and find it has potential to delay clinical decline, particularly if applied early in the disease process. Randomized controlled trials of cognitive intervention in HD should be implemented as a next step to gauging the efficacy of this approach to improve outcomes for those with the HD gene.
Publisher: Cambridge University Press (CUP)
Date: 28-12-2017
DOI: 10.1017/S1355617717001308
Abstract: Objectives: People with Huntington’s disease (HD) experience poor social quality of life, relationship breakdown, and social withdrawal, which are mediated to some extent by socially debilitating neuropsychiatric symptoms, such as apathy and disinhibition. Social cognitive symptoms, such as impaired emotion recognition, also occur in HD, however, the extent of their association with these socially debilitating neuropsychiatric symptoms is unknown. Our study examined the relationship between emotion recognition and symptom ratings of apathy and disinhibition in HD. Methods: Thirty-two people with premanifest or symptomatic-HD completed Part 1 of The Awareness of Social Inference Test (TASIT), which is a facial emotion recognition task. In addition, we obtained severity ratings for apathy and disinhibition on the Frontal Systems Behavior Scale (FrSBe) from a close family member. Our analyses used motor symptom severity as a proxy for disease progression. Results: Emotion recognition performance was significantly associated with family-ratings of apathy, above and beyond their shared association with disease severity. We found a similar pattern for disinhibition ratings, which fell short of statistical significance. As expected, worse emotion recognition performance was correlated with higher severity in FrSBe symptom ratings. Conclusions: Our findings suggest that emotion recognition abilities relate to key socially debilitating neuropsychiatric symptoms in HD. Our results help to understand the functional significance of emotion recognition impairments in HD, and may have implications for the development of remediation programs aimed at improving patients’ social quality of life. ( JINS , 2018, 24 , 417–423)
Publisher: American Psychological Association (APA)
Date: 11-2018
DOI: 10.1037/NEU0000479
Abstract: Unawareness of neuropsychiatric symptoms appears to be common in Huntington's disease (HD), but the clinical correlates of unawareness are unclear. Identifying predictors of unawareness is important for improving diagnosis of neuropsychiatric symptoms, and cognitive impairment, specifically executive impairment, may be a potential important predictor of unawareness. The authors examined whether unawareness of neuropsychiatric symptoms is more common in early HD compared to premanifest HD, and whether executive task performance was associated with awareness, independent of demographic, motor or mood variables. One hundred thirty-two gene-positive participants (60 premanifest and 72 early diagnosed) from the multicenter TRACK-HD study were included. Participants and their informants completed self and informant versions of the Frontal Systems Behavior Scale, which measures executive dysfunction, apathy, and disinhibition symptoms. Awareness was measured as the discrepancy between self- and informant-reports across premanifest and early HD groups. Participants' executive task performance was then assessed as a predictor of unawareness across the whole group. Premanifest participants reported higher levels of executive dysfunction, apathy and disinhibition than their informants, whereas early HD participants reported less executive dysfunction and apathy than their informants, indicating that unawareness is more common after diagnosis. Impaired executive task performance was related to unawareness of executive dysfunction and apathy, independent of demographic, motor and mood variables. Executive impairment is a useful early predictor of unawareness of neuropsychiatric symptoms in HD. Clinicians should closely monitor HD patients with executive impairment for unawareness, and consider this when assessing neuropsychiatric symptoms in HD and providing education to patients and families. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Publisher: Informa UK Limited
Date: 21-03-2017
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.JNEUMETH.2015.12.007
Abstract: The number of studies examining cognition in Huntington's disease (HD) has increased dramatically in recent decades, and cognitive research methods in HD have become much more sophisticated. In this review, we provide a summary of the advances in cognitive research in HD to date, and outline the key considerations for researchers planning to include cognitive assessment in their studies of HD. In particular, we discuss consideration of structure-function relationships, selection of tests appropriate to the population, choice of materials and issues of intellectual property, consideration of variables which can confound studies of cognition in HD, practice effects, and specific issues for multi-site research. Finally, we discuss future directions for cognitive assessment in HD research.
Publisher: American Psychological Association (APA)
Date: 09-2021
DOI: 10.1037/NEU0000757
Publisher: Cambridge University Press (CUP)
Date: 15-02-2019
DOI: 10.1017/S1355617718001224
Abstract: Objectives: Previous research has demonstrated an association between emotion recognition and apathy in several neurological conditions involving fronto-striatal pathology, including Parkinson’s disease and brain injury. In line with these findings, we aimed to determine whether apathetic participants with early Huntington’s disease (HD) were more impaired on an emotion recognition task compared to non-apathetic participants and healthy controls. Methods: We included 43 participants from the TRACK-HD study who reported apathy on the Problem Behaviours Assessment – short version (PBA-S), 67 participants who reported no apathy, and 107 controls matched for age, sex, and level of education. During their baseline TRACK-HD visit, participants completed a battery of cognitive and psychological tests including an emotion recognition task, the Hospital Depression and Anxiety Scale (HADS) and were assessed on the PBA-S. Results: Compared to the non-apathetic group and the control group, the apathetic group were impaired on the recognition of happy facial expressions, after controlling for depression symptomology on the HADS and general disease progression (Unified Huntington’s Disease Rating Scale total motor score). This was despite no difference between the apathetic and non-apathetic group on overall cognitive functioning assessed by a cognitive composite score. Conclusions: Impairment of the recognition of happy expressions may be part of the clinical picture of apathy in HD. While shared reliance on frontostriatal pathways may broadly explain associations between emotion recognition and apathy found across several patient groups, further work is needed to determine what relationships exist between recognition of specific emotions, distinct subtypes of apathy and underlying neuropathology. ( JINS , 2019, 25 , 453–461)
Publisher: Elsevier BV
Date: 12-2020
Publisher: Springer Science and Business Media LLC
Date: 03-09-2021
Publisher: Future Medicine Ltd
Date: 06-2022
Abstract: Aim: In Huntington's disease (HD) and Parkinson's disease (PD), apathy is a frequently cited barrier to participation in physical activity. Current diagnostic criteria emphasize dissociable variants of apathy that differentially affect goal-directed behavior. How these dimensions present and affect physical activity in HD and PD is unknown. Methods: Using a qualitative approach, we examined the experience of apathy and its impact on physical activity in 20 people with early-manifest HD or idiopathic PD. Results: Two major themes emerged: the multidimensionality of apathy, including initiation or goal-identification difficulties, and the interplay of apathy and fatigue and facilitators of physical activity, including routines, safe environments and education. Conclusion: Physical activity interventions tailored to apathy phenotypes may maximize participant engagement.
Publisher: Informa UK Limited
Date: 02-04-2016
Publisher: Elsevier
Date: 2017
Publisher: Elsevier BV
Date: 08-2015
Start Date: 08-2021
End Date: 12-2024
Amount: $437,623.00
Funder: Australian Research Council
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