Poster Session 06 Program Schedule
02/15/2024
04:00 pm - 05:15 pm
Room: Shubert Complex (Posters 1-60)
Poster Session 06: Aging | MCI | Neurodegenerative Disease - PART 2
Final Abstract #56
The Evolution of Motivational Disturbances Over the Disease Course in Frontotemporal Dementia and Alzheimer’s Disease
Muireann Irish, The University of Sydney, Sydney, Australia
Julie Behenska, The University of Sydney, Sydney, Australia
Rebekah Ahmed, The University of Sydney, Sydney, Australia
Olivier Piguet, The University of Sydney, Sydney, Australia
Category: Dementia (Non-AD)
Keyword 1: apathy
Keyword 2: motivation
Keyword 3: dementia - Alzheimer's disease
Objective:
Mounting evidence points to profound changes in motivation in frontotemporal dementia (FTD), manifesting in a loss of goal-directed behaviour (apathy) and a decreased capacity to experience or pursue pleasure (anhedonia). Presence of these symptoms is associated with a decrease in functional capacity, which in turn, exacerbates carer burden and stress. It remains unclear how motivational symptoms evolve over the disease course in FTD or their prognostic value in terms of long-term patient and carer outcomes. The objective of this study was to chart the evolution of apathy and anhedonia in FTD using a longitudinal approach.
Participants and Methods:
A total of 86 participants were recruited for this study including 28 clinically probable behavioural variant FTD (bvFTD), 24 primary progressive aphasia (PPA), 14 typical Alzheimer’s disease (AD) participants as a disease control group, and 20 matched healthy older controls. The Dimensional Apathy Scale (DApS) and Snaith Hamilton Pleasure Scale (SHAPS) were used to index carer-rated apathy and anhedonia, respectively. Functional impairment was evaluated using the Frontotemporal Dementia Rating Scale, while carer burden was measured using the Zarit Burden Interview. Participants were assessed at baseline and then at yearly intervals up to a maximum of 90 months. Linear Mixed Effect models were used to track motivational profiles from baseline across the study period, while correlation analyses explored whether baseline apathy and anhedonia severity related to patient functional decline and carer burden.
Results:
Clinically significant apathy was already established in bvFTD (p =.007) and AD (p =.05) at baseline, with PPA patients crossing the threshold for apathy by 30 months follow-up. In contrast, bvFTD (p <.0001) and PPA (p =.008) patients displayed clinically significant levels of anhedonia at baseline. While AD patients were not anhedonic at baseline (p >.05), by 6 months follow-up they had crossed the threshold for clinically significant anhedonia. Correlation analyses in the combined patient cohort indicated that baseline levels of apathy and anhedonia were strongly associated with functional impairment across the 90 month period (apathy r values: .24 to .66; anhedonia r values: -.39 to -.77) and predicted carer burden up to 3 years following initial assessment (all r values > .30). Finally, the linear mixed effect models revealed that rates of progression for apathy and anhedonia were relatively stable in bvFTD (all p values >.17), while for AD, apathy (slope: .2935) and anhedonia (slope: -.2037) severity increased more rapidly with disease progression (all p values < .035).
Conclusions:
As the first study to document the evolution of apathy and anhedonia in dementia, our findings suggest that motivational disturbances unfold at different rates depending on dementia subtype. Apathy and anhedonia in bvFTD and PPA reach a critical threshold early in the disease course and appear to plateau, while these symptoms increase swiftly in AD patients. Our findings underscore the need to invest in psychoeducation and development of targeted interventions to alleviate symptom burden for those affected.
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