Apathy self-awareness and its neural correlates in Parkinson's Disease

Apathy is a prevalent non-motor symptom in Parkinson's disease (PD) that negatively impacts quality of life. Impaired self-awareness of apathy (ISA-a) further impacts patient care by limiting engagement. While apathy has been associated with reduced fronto-striatal functional connectivity (FC), the neural basis of ISA-a remains unclear. We examined ISA-a in 52 individuals and the neural basis of ISA-a in 35 individuals with PD using a dimensional approach (i.e., initiation, executive, and emotional apathy) and resting-state fMRI (3T scanner). Apathetic PD patients (42%) showed poorer self-awareness than non-apathetic peers. Apathetic PD patients showed a trend towards reduced FC between the left anterior cingulate cortex (ACC) and the left nucleus accumbens (NAcc). A trend for ISA-a in the emotional domain showed altered FC between the left NAcc and orbitofrontal cortices, and the right ACC and right anterior insular cortex. These findings suggest potential neural mechanisms underlying apathy and ISA-a to be studied in larger populations.