Apathy and its impact on carer burden and psychological wellbeing in primary progressive aphasia

Objective: While patients with primary progressive aphasia (PPA) typically present with predominant language impairment, behavioural symptoms, such as apathy, are often under-recognised. We aimed to systematically characterise apathy across the three recognised subtypes of PPA, plus atypical right-lateralised presentations of semantic dementia, and to evaluate the impact of apathy on carer burden and psychological wellbeing. Methods: Baseline assessments from 114 PPA patients were included: 31 left semantic dementia (left SD) 16 right semantic dementia (right SD), 30 progressive nonfluent aphasia (PNFA) and 37 logopenic progressive aphasia (LPA). Clinician (Neuropsychiatric Inventory; NPI) and carer rated (Cambridge Behavioural Inventory; CBI, Frontal Systems Behaviour Scale; FrSBe) measures were used to quantify symptoms of apathy, and carer burden and psychological wellbeing were determined using the Zarit Burden Interview and Depression, Anxiety and Stress Scale. Results: On the NPI, symptoms of apathy were present in 39% left SD, 56% right SD, 33% PNFA and 43% LPA patients. Multiple regression analysis revealed that 17.9% of the variance in carer burden was uniquely explained by scores on carer rated measures of apathy (CBI, FrSBe), even after accounting for diagnosis, disease duration, and cognitive and language impairment. Conclusions: Apathy is much more common than current diagnostic criteria for PPA would suggest, though the severity of apathy is similar across patient groups. Increased awareness and routine assessments of apathy symptoms are needed, together with targeted pharmacological and behavioural interventions. Moreover, as apathy substantially contributes to carer burden in PPA, psychoeducation addressing behavioural symptoms may be beneficial.