Apathy in Parkinson's disease: differences between caregiver's report and self-evaluation

Apathy is a state of diminished goal-directed speech, motor activity and emotions. The prevalence of apathy in Parkinson's disease (PD) ranges from 16 to 62%. Several studies have investigated the relationships between apathy and other dimensions of PD, but little is known about possible discrepancies between self-evaluation (SE) and caregiver reporting (CR) of this symptom. The aim of this study is twofold: 1) to investigate the differences in apathy evaluations according to the point of view from which apathy is reported (SE vs CR); 2) to identify the possible relationships between each of the two evaluations (SE and CR) and cognitive and affective dimensions of PD. Forty-eight patients with PD were assessed using the Apathy Evaluation Scale (AES) in its SE and CR versions (AES-SE and AES-CR); cognitive, affective and behavioral symptoms were also assessed. AES-SE scores were significantly higher than AESCR ones. Neither AES version correlated with depression, whereas both correlated with motor impairment, disease stage and behavioral symptoms. Mini-Mental State Examination and Frontal Assessment Battery scores showed significant negative correlations only with AES-SE scores. Our findings suggest that the point of view from which apathy is seen can lead to significant discrepancies, even when using the same tool. This should be taken into account in order to obtain correct assessment of this disabling and distressing symptom.