The association of apathy with central fatigue perception in patients with Parkinson's disease

This study was designed to evaluate the association of different apathy conceptual domains with central fatigue perception in Parkinson's disease (PD), taking into consideration other nonmotor symptoms. To this end, 90 consecutive PD patients (66.7% men, mean age 61.44 ± 13.2 years) underwent a comprehensive neurological and psychiatric examination, including the Structured Clinical Interview for DSM-IV, Parkinson Fatigue Scale, Lille Apathy Rating Scale, Hamilton Depression Scale, and State-Trait Anxiety Inventory. A linear regression model was applied to analyze the relationship between apathy and its different conceptual domains with fatigue severity. Thirty-seven (41.1%) patients presented fatigue. Its presence was associated with higher apathy total scores and with 2 of the 4 apathy conceptual domains (less intellectual curiosity and action initiation) with no associations in the emotion and self-awareness apathy domains. Patients with fatigue scored higher in depression (p < .001), anxiety trait (p < .001), and anxiety state (p = .006). Regression analysis identified that Lille Apathy Rating Scale total score (p = .008), intellectual curiosity and action initiation apathy subscores (p = .001 and p = .003) were associated with fatigue severity in patients with right predominant motor symptoms. Sex, age, disease duration, clinical stage, motor complications, prior psychiatric disorders, and treatment were not significantly associated with presence of fatigue. The findings suggest that some apathy-related domains are more frequent in fatigued PD and may be related with fatigue severity.