LAUSR

Compare cognitive performance in early-stage Parkinson Disease (PD) participants with and without depression. Data from the Parkinson’s Progression Marker Initiative were utilized. We examined data from 422 participants diagnosed with PD within the previous two years (age = 61.7±9.7 years, education = 15.6±3.0 years). Depressive symptoms were assessed using the Geriatric Depression Scale (GDS-15) using a cutoff score of ≤5 to indicate the absence of clinical depression. Cognitive tests included Hopkins Verbal Memory Test-Revised (HVLT-R), Judgment of Line Orientation (JLO), Letter-Number Sequencing (LNS), Symbol Digit Modalities Test (SDMT), and Category Fluency. Motor scores were measured by the Movement Disorder Society Unified Parkinson’s Disease Rating Scale Part III. Demographic and clinical variables for the two groups were compared using independent samples t-tests and chi-square analyses. The non-depressed group (n = 280) was significantly older; t(246.08) = 2.25, p = .026 and had higher education; t(420) = 2.35, p = .019; and duration of PD symptoms; t(170.58) = -2.13, p = .035 than the depressed group (n = 142). The groups did not differ in terms of race, gender, handedness, side of onset, or severity of motor symptoms. There was no significant differences in performance on HVLT, JLO, SDMT, or Category Fluency; however, the non-depressed group performed better on LNS than the depressed group, t(420) = 2.05, p = .041. There is no significant difference in cognitive performance between early-stage PD participants with and without depression, with the exception of significantly lower working memory performance in the depressed group.