Body side of motor symptom onset in Parkinson's disease is associated with memory performance.

The relation of body side of motor symptom onset in Parkinson's disease (PD) to memory measures associated with hemispheric dominance was examined. Fourteen patients with right body side motor symptom onset (RPD, inferred left hemisphere dysfunction) and 16 patients with left side onset (LPD, right hemisphere dysfunction) were administered measures of verbal (Hopkins Verbal Learning Test-Revised) and visual memory (Brief Visual Memory Test-Revised), that require similar task demands and are associated with left or right hemisphere dominance, respectively. The LPD group demonstrated poorer visual than verbal memory, both within group and in comparison to the RPD group. By contrast, the RPD group showed poorer verbal than visual memory within group. These findings suggest that side of motor symptom onset is associated with asymmetrical memory dysfunction.