VIGILANCE PERFORMANCE IN PARKINSONS-DISEASE AND DEPRESSION

Patients with Parkinson's disease (PD), patients with Major Depression (MD) and normal control (NC) subjects were administered a continuous performance test (CPT) under neutral and incentive conditions. Patient s made more errors than NC subjects with the MD group making a disprop ortionately large number of omission errors and the PD group tending t o make commission errors. Incentive reduced errors across groups. Reac tion times were slowest in the MD group. The pattern of findings in pa tients with MD is consistent with a failure of effort-demanding cognit ive processes. In contrast, nondemented patients with PD appeared to h ave deficiencies in executive control. A previously reported paradoxic al effect of incentive on recognition memory performance in depressed patients did not generalize to a vigilance task.