Longitudinal changes in behaviour, mood, and functional capacity in the primary progressive aphasia variants.

Primary progressive aphasia (PPA) is a neurodegenerative clinical syndrome characterised by a progressive decline in speech and language functions. Deficits in behaviour, mood, and functional capacity are reported in PPA but are less well understood. This study examined the PPA variants' profiles on these domains at initial presentation and over time and evaluated their relations to overall cognitive ability. Behaviour, mood, and functional capacity were measured annually (over ~6 years) in 145 individuals diagnosed with PPA (41 logopenic [lv-PPA], 44 non-fluent [nfv-PPA], and 60 semantic variants [sv-PPA]) using the Cambridge Behavioural Inventory-Revised (CBI-R) carer questionnaire. Overall cognition was assessed annually with the Addenbrooke's Cognitive Examination-III. Distinct profiles were observed across PPA syndromes. Notably, sv-PPA carers reported greater behavioural, eating, and motivational disturbances than the other PPA variants throughout the disease course. Reported memory problems were also greater in sv-PPA and lv-PPA than in nfv-PPA across all time points. These disturbances occurred in the context of the sv-PPA group demonstrating a slower rate of cognitive decline than the lv-PPA group and a parallel rate to that found in the nfv-PPA group. Associations between overall cognition and the CBI-R domains were trivial at baseline assessment; however, distinct profiles emerged when mapping each syndrome's overall cognitive decline with their behavioural, mood, and functional trajectories. Our findings demonstrate that the evolving behaviour, mood, and functional capacity profiles of the PPA variants are distinct and extend beyond the primary disorder of language. These findings have important implications for clinical management and caregiver education in PPA.