Apathy in patients with Parkinson disease as a function of side of onset.

Background:In previous studies among patients with Parkinson disease (PD) who were administered the Apathy Evaluation Scale (AES), between 12% and 51% evidenced clinically significant apathy. Although apathy is a risk factor for dementia, its causes and clinical correlates have not been adequately studied. In particular, side of onset of disease, though a likely predictor of apathy and dementia, has not been thoroughly investigated.Methods:A total of 30 mid-stage patients with PD and 35 community-dwelling elderly control patients (CPs) were administered the AES (self version) along with a battery of cognitive and neuropsychiatric assessments. Persons close to patients with PD and CPs completed the AES—other (informant) version about the patient or CP. Multiple linear regression analysis examined predictors of apathy severity after controlling for mood, levodopa dosage equivalents (LDEs), gender, age, and disease severity (Hoehn–Yahr [H-Y] stage).Results:Patients with right-onset disease more frequently ex...