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 similar to 6 years) in 145 individuals diagnosed with PPA (41 logopenic [Iv-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 Iv-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 Iv-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.

Automated summary

This study found distinct profiles in behavior, mood, and functional capacity among different variants of Primary Progressive Aphasia (PPA), which go beyond the primary language disorder. Caregivers of semantic variant PPA reported greater behavioral disturbances than other variants, with memory problems also more severe in semantic and logopenic variants compared to non-fluent variant. These findings have important implications for clinical management and caregiver education in PPA.