10 results on '"Rebekah M Ahmed"'
Search Results
2. Distinct hypothalamic involvement in the amyotrophic lateral sclerosis-frontotemporal dementia spectrum
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Nga Yan Tse, Martina Bocchetta, Emily G. Todd, Emma M. Devenney, Sicong Tu, Jashelle Caga, John R. Hodges, Glenda M. Halliday, Muireann Irish, Matthew C. Kiernan, Olivier Piguet, Jonathan D. Rohrer, and Rebekah M. Ahmed
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Frontotemporal dementia ,Amyotrophic lateral sclerosis ,Hypothalamus ,Neuroimaging ,Neuropathophysiology ,Cognitive and behavioural impairment ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Background: Hypothalamic dysregulation plays an established role in eating abnormalities in behavioural variant frontotemporal dementia (bvFTD) and amyotrophic lateral sclerosis (ALS). Its contribution to cognitive and behavioural impairments, however, remains unexplored. Methods: Correlation between hypothalamic subregion atrophy and cognitive and behavioural impairments was examined in a large sample of 211 participants (52 pure ALS, 42 mixed ALS-FTD, 59 bvFTD, and 58 age- and education- matched healthy controls). Results: Graded variation in hypothalamic involvement but relative sparing of the inferior tuberal region was evident across all patient groups. Bilateral anterior inferior, anterior superior, and posterior hypothalamic subregions were selectively implicated in memory, fluency and processing speed impairments in addition to apathy and abnormal eating habits, taking into account disease duration, age, sex, total intracranial volume, and acquisition parameters (all p ≤ .001). Conclusions: These findings revealed that subdivisions of the hypothalamus are differentially affected in the ALS-FTD spectrum and contribute to canonical cognitive and behavioural disturbances beyond eating abnormalities. The anterior superior and superior tuberal subregions containing the paraventricular nucleus (housing oxytocin-producing neurons) displayed the greatest volume loss in bvFTD and ALS-FTD, and ALS, respectively. Importantly, the inferior tuberal subregion housing the arcuate nucleus (containing different groups of neuroendocrine neurons) was selectively preserved across the ALS-FTD spectrum, supporting pathophysiological findings of discrete neuropeptide expression abnormalities that may underlie the pathogenesis of autonomic and metabolic abnormalities and potentially certain cognitive and behavioural symptom manifestations, representing avenues for more refined symptomatic treatment targets.
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- 2023
- Full Text
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3. Error profiles of facial emotion recognition in frontotemporal dementia and Alzheimer’s disease
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Kimberly Gressie, Fiona Kumfor, Her Teng, David Foxe, Emma Devenney, Rebekah M. Ahmed, and Olivier Piguet
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Psychiatry and Mental health ,Clinical Psychology ,Geriatrics and Gerontology ,Gerontology - Abstract
Objectives: To identify the patterns of errors in facial emotion recognition in frontotemporal dementia (FTD) subtypes compared with Alzheimer’s disease (AD) and healthy controls. Design: Retrospective analysis. Setting: Participants were recruited from FRONTIER, the frontotemporal dementia research group at the University of Sydney, Australia. Participants: A total of 356 participants (behavioral-variant FTD (bvFTD): 62, semantic dementia (SD)-left: 29, SD-right: 14, progressive non-fluent aphasia (PNFA): 21, AD: 76, controls: 90) were included. Measurements: Facial emotion recognition was assessed using the Facial Affect Selection Task, a word-face matching task measuring recognition of the six basic emotions (anger, disgust, fear, happiness, sadness, and surprise), as well as neutral emotion, portrayed by black and white faces. Results: Overall, all clinical groups performed significantly worse than controls with the exception of the PNFA subgroup (p = .051). The SD-right group scored worse than all other clinical groups (all p values < .027) and the bvFTD subgroup performed worse than the PNFA group (p < .001). The most frequent errors were in response to the facial emotions disgust (26.1%) and fear (22.9%). The primary error response to each target emotion was identified; patterns of errors were similar across all clinical groups. Conclusions: Facial emotion recognition is impaired in FTD and AD compared to healthy controls. Within FTD, bvFTD and SD-right are particularly impaired. Dementia groups cannot be distinguished based on error responses alone. Implications for future clinical diagnosis and research are discussed.
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- 2023
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4. Olfactory Bulb Integrity in Frontotemporal Dementia and Alzheimer’s Disease
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Sarah E. Carnemolla, Fiona Kumfor, Cheng Tao Liang, David Foxe, Rebekah M. Ahmed, and Olivier Piguet
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Olfaction Disorders ,Psychiatry and Mental health ,Clinical Psychology ,Alzheimer Disease ,Frontotemporal Dementia ,General Neuroscience ,Aphasia ,Humans ,General Medicine ,Atrophy ,Geriatrics and Gerontology ,Magnetic Resonance Imaging ,Olfactory Bulb - Abstract
Background: Olfactory dysfunction is highly prevalent in dementia syndromes, including Alzheimer’s disease (AD) and frontotemporal dementia (FTD). The structural integrity of the olfactory bulb (OB) is thought to play a critical role in odor detection and identification, but no MRI study has measured OB volume in FTD, or measured OB volume longitudinally in AD. Objective: To measure OB volume in FTD and AD patients longitudinally using MRI. Methods: This study measured OB volumes using MRI in patients diagnosed with behavioral-variant FTD (n = 55), semantic dementia (n = 34), progressive non-fluent aphasia (n = 30), AD (n = 50), and healthy age-matched controls (n = 55) at their first visit to a dementia research clinic (‘baseline’). Imaging data in patients 12-months later were analyzed where available (n = 84) for longitudinal assessment. Volumes of subcortical and cortical olfactory regions (‘olfactory network’) were obtained via surface-based morphometry. Results: Results revealed that in AD and FTD at baseline, OB volumes were similar to controls, whereas volumes of olfactory network regions were significantly reduced in all patient groups except in progressive non-fluent aphasia. Longitudinal data revealed that OB volume became significantly reduced (10–25% volume reduction) in all dementia groups with disease progression. Conclusion: Olfactory dysfunction is common in patients diagnosed with AD or FTD, but our results indicate that there is no detectable volume loss to the OBs upon first presentation to the clinic. Our findings indicate that the OBs become detectably atrophied later in the disease process. OB atrophy indicates the potential usefulness for OBs to be targeted in interventions to improve olfactory function.
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- 2022
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5. Schizotypal traits across the amyotrophic lateral sclerosis–frontotemporal dementia spectrum: pathomechanistic insights
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Nga Yan Tse, Sicong Tu, Yu Chen, Jashelle Caga, Carol Dobson-Stone, John B. Kwok, Glenda M. Halliday, Rebekah M. Ahmed, John R. Hodges, Olivier Piguet, Matthew C. Kiernan, and Emma M. Devenney
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Neurology ,mental disorders ,Neurology (clinical) - Abstract
Background Psychiatric presentations similar to that observed in primary psychiatric disorders are well described across the amyotrophic lateral sclerosis–frontotemporal dementia (ALS–FTD) spectrum. Despite this, schizotypal personality traits associated with increased risks of clinical psychosis development and poor psychosocial outcomes have never been examined. The current study aimed to provide the first exploration of schizotypal traits and its neural underpinnings in the ALS–FTD spectrum to gain insights into a broader spectrum of psychiatric overlap with psychiatric disorders. Methods Schizotypal traits were assessed using the targeted Schizotypal Personality Questionnaire in 99 participants (35 behavioural variant FTD, 10 ALS–FTD and 37 ALS patients, and 17 age-, sex- and education-matched healthy controls). Voxel-based morphometry analysis of whole-brain grey matter volume was conducted. Results Relative to controls, pervasive schizotypal personality traits across positive and negative schizotypy and disorganised thought disorders were identified in behavioural variant FTD, ALS (with the exception of negative schizotypy) and ALS–FTDALS–FTD patients (all p Conclusions The frontal–striatal–limbic regions underpinning manifestation of schizotypy in the ALS–FTDALS–FTD spectrum are similar to that established in previous schizophrenia research. This finding expands the concept of a psychiatric overlap in ALS–FTD and schizophrenia, and suggests potentially common underlying mechanisms involving disruptions to frontal-striatal-limbic networks, warranting a transdiagnostic approach for future investigations.
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- 2022
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6. Pearls and Oy-sters: Huntington Disease Presenting as Primary Progressive Aphasia: A Case of Semantics
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Antonia J Clarke, David Manser, Ronald Fleischer GradDipGC, Michael Fulham, and Rebekah M Ahmed
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Neurology (clinical) - Abstract
We present a case of semantic variant primary progressive aphasia (PPA) as the presenting feature in a patient with Huntington disease (HD). The patient initially developed progressive language impairment including impaired naming, object knowledge and single word comprehension and then developed chorea and behavioural changes. Magnetic resonance imaging (MRI) of the brain showed left anterior temporal lobe and hippocampal atrophy. A neurological FDG PET/CT showed reduced metabolism in the head of the left caudate nucleus. Huntingtin gene testing revealed an expansion of 39 CAG repeats in one allele. This case outlines the substantial overlap between the clinical presentation of HD and frontotemporal lobar degeneration (FTLD) syndromes and provides commentary on the investigation of these neurodegenerative diseases.
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- 2023
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7. Mapping behavioural, cognitive and affective transdiagnostic dimensions in frontotemporal dementia
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Siddharth Ramanan, Hashim El-Omar, Daniel Roquet, Rebekah M Ahmed, John R Hodges, Olivier Piguet, Matthew A Lambon Ralph, Muireann Irish, Ahmed, Rebekah M [0000-0001-6996-8317], Piguet, Olivier [0000-0002-6696-1440], Lambon Ralph, Matthew A [0000-0001-5907-2488], Irish, Muireann [0000-0002-4950-8169], and Apollo - University of Cambridge Repository
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Cellular and Molecular Neuroscience ,Psychiatry and Mental health ,Neurology ,principal component analysis ,transdiagnostic ,semantic variant primary progressive aphasia ,heterogeneity ,Biological Psychiatry ,dementia - Abstract
Two common clinical variants of frontotemporal dementia are the behavioural variant frontotemporal dementia, presenting with behavioural and personality changes attributable to prefrontal atrophy, and semantic dementia, displaying early semantic dysfunction primarily due to anterior temporal degeneration. Despite representing independent diagnostic entities, mounting evidence indicates overlapping cognitive–behavioural profiles in these syndromes, particularly with disease progression. Why such overlap occurs remains unclear. Understanding the nature of this overlap, however, is essential to improve early diagnosis, characterization and management of those affected. Here, we explored common cognitive–behavioural and neural mechanisms contributing to heterogeneous frontotemporal dementia presentations, irrespective of clinical diagnosis. This transdiagnostic approach allowed us to ascertain whether symptoms not currently considered core to these two syndromes are present in a significant proportion of cases and to explore the neural basis of clinical heterogeneity. Sixty-two frontotemporal dementia patients (31 behavioural variant frontotemporal dementia and 31 semantic dementia) underwent comprehensive neuropsychological, behavioural and structural neuroimaging assessments. Orthogonally rotated principal component analysis of neuropsychological and behavioural data uncovered eight statistically independent factors explaining the majority of cognitive–behavioural performance variation in behavioural variant frontotemporal dementia and semantic dementia. These factors included Behavioural changes, Semantic dysfunction, General Cognition, Executive function, Initiation, Disinhibition, Visuospatial function and Affective changes. Marked individual-level overlap between behavioural variant frontotemporal dementia and semantic dementia was evident on the Behavioural changes, General Cognition, Initiation, Disinhibition and Affective changes factors. Compared to behavioural variant frontotemporal dementia, semantic dementia patients displayed disproportionate impairment on the Semantic dysfunction factor, whereas greater impairment on Executive and Visuospatial function factors was noted in behavioural variant frontotemporal dementia. Both patient groups showed comparable magnitude of atrophy to frontal regions, whereas severe temporal lobe atrophy was characteristic of semantic dementia. Whole-brain voxel-based morphometry correlations with emergent factors revealed associations between fronto-insular and striatal grey matter changes with Behavioural, Executive and Initiation factor performance, bilateral temporal atrophy with Semantic dysfunction factor scores, parietal-subcortical regions with General Cognitive performance and ventral temporal atrophy associated with Visuospatial factor scores. Together, these findings indicate that cognitive–behavioural overlap (i) occurs systematically in frontotemporal dementia; (ii) varies in a graded manner between individuals and (iii) is associated with degeneration of different neural systems. Our findings suggest that phenotypic heterogeneity in frontotemporal dementia syndromes can be captured along continuous, multidimensional spectra of cognitive–behavioural changes. This has implications for the diagnosis of both syndromes amidst overlapping features as well as the design of symptomatic treatments applicable to multiple syndromes.
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- 2023
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8. Distinct hypothalamic involvement in the amyotrophic lateral sclerosis-frontotemporal dementia spectrum
- Author
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Nga Yan Tse, Martina Bocchetta, Emily G. Todd, Emma M. Devenney, Sicong Tu, Jashelle Caga, John R. Hodges, Glenda M. Halliday, Muireann Irish, Matthew C. Kiernan, Olivier Piguet, Jonathan D. Rohrer, and Rebekah M. Ahmed
- Subjects
Neuropathophysiology ,Cognitive and behavioural impairment ,Neurology ,Cognitive Neuroscience ,Hypothalamus ,Radiology, Nuclear Medicine and imaging ,Neuroimaging ,Neurology (clinical) ,Amyotrophic lateral sclerosis ,Frontotemporal dementia - Abstract
Background Hypothalamic dysregulation plays an established role in eating abnormalities in behavioural variant frontotemporal dementia (bvFTD) and amyotrophic lateral sclerosis (ALS). Its contribution to cognitive and behavioural impairments, however, remains unexplored. Methods Correlation between hypothalamic subregion atrophy and cognitive and behavioural impairments was examined in a large sample of 211 participants (52 pure ALS, 42 mixed ALS-FTD, 59 bvFTD, and 58 age- and education- matched healthy controls). Results Graded variation in hypothalamic involvement but relative sparing of the inferior tuberal region was evident across all patient groups. Bilateral anterior inferior, anterior superior, and posterior hypothalamic subregions were selectively implicated in memory, fluency and processing speed impairments in addition to apathy and abnormal eating habits, taking into account disease duration, age, sex, total intracranial volume, and acquisition parameters (all p ≤ .001). Conclusions These findings revealed that subdivisions of the hypothalamus are differentially affected in the ALS-FTD spectrum and contribute to canonical cognitive and behavioural disturbances beyond eating abnormalities. The anterior superior and superior tuberal subregions containing the paraventricular nucleus (housing oxytocin-producing neurons) displayed the greatest volume loss in bvFTD and ALS-FTD, and ALS, respectively. Importantly, the inferior tuberal subregion housing the arcuate nucleus (containing different groups of neuroendocrine neurons) was selectively preserved across the ALS-FTD spectrum, supporting pathophysiological findings of discrete neuropeptide expression abnormalities that may underlie the pathogenesis of autonomic and metabolic abnormalities and potentially certain cognitive and behavioural symptom manifestations, representing avenues for more refined symptomatic treatment targets. National Health and Medical Research Council of Australia program (#1037746 and #1132524) and dementia team (#1095127) grants and the Australian Research Council Centre of Excellence in Cognition and its Disorders Memory Program (#CE110001021). Dr E.M. Devenney is supported by a MNDRIA post-doctoral fellowship. Dr S. Tu is supported by a NHMRC post-doctoral fellowship (APP1121859). Dr R.M. Ahmed is supported by a NHMRC post-doctoral fellowship. Prof G.M. Halliday is a NHMRC Leadership Fellow (#1176607). Prof M.C. Kiernan received funding support from NHMRC Partnership Grant (#1153439) and Practitioner Fellowship (#115609). Prof O. Piguet is supported by a NHMRC Leadership Fellowship (GNT2008020). Dr M. Bocchetta is supported by a Fellowship award from the Alzheimer’s Society, UK (AS-JF-19a-004-517). Dr M. Bocchetta’s work was also supported by the UK Dementia Research Institute which receives its funding from DRI ltd, funded by the UK Medical Research Council, Alzheimer’s Society and Alzheimer’s Research UK. Dr M. Bocchetta acknowledges the support of NVIDIA Corporation with the donation of the Titan V GPU used for part of the analyses in this research. Prof J. D Rohrer is supported by the Miriam Marks Brain Research UK Senior Fellowship and has received funding from an MRC Clinician Scientist Fellowship (MR/M008525/1) and the NIHR Rare Disease Translational Research Collaboration (BRC149/NS/MH).
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- 2022
9. Thalamic and Cerebellar Regional Involvement across the ALS-FTD Spectrum and the Effect of
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Martina, Bocchetta, Emily G, Todd, Nga Yan, Tse, Emma M, Devenney, Sicong, Tu, Jashelle, Caga, John R, Hodges, Glenda M, Halliday, Muireann, Irish, Olivier, Piguet, Matthew C, Kiernan, Jonathan D, Rohrer, and Rebekah M, Ahmed
- Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are part of the same disease spectrum. While thalamic-cerebellar degeneration has been observed in
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- 2022
10. The Holy Grail: highlighting the need for equitable access to dementia treatments and clinical trials
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Rebekah M. Ahmed, Olivier Piguet, Catherine J. Mummery, Sharon L. Naismith, and Muireann Irish
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Dementia ,Alzheimer's disease ,Mono-clonal antibodies ,Treatment ,Frototemporal dementia ,Public aspects of medicine ,RA1-1270 - Abstract
Summary: In the last 5 years significant progress has been made in potential dementia treatments, yet many of these treatments come with significant burdens on the healthcare system that may limit access to treatment and care for patients. Often patients in remote and rural regions and those in low income regions are disadvantaged. Many clinical trials for dementia patients are biased to recruiting a homogenous group of patients that does not represent cultural and linguistic diversity, meaning the generalisability of trials is limited. This viewpoint discusses the barriers to access to early treatments and clinical trials for patients with dementia and offers a potential framework to address these including provision of infrastructure, regulatory change and patient education.
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- 2025
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