[Event-related potential and visual evoked potential in patients with Parkinson's disease]

The event-related potential (ERP) and visual evoked potential (VEP) were recorded in 28 patients with Parkinson's disease (PD) and 28 normal subjects. Nine of the PD patients had dementia and 19 did not. Dementia was evaluated according to the criteria for dementia assigned by the DSM III-R, and mental faculties were estimated using the Mini-Mental State Examination (MMSE). ERP was recorded during auditory discriminative tasks. The latencies of N100, P200, N200 and P300 from the Pz region were measured. VEP was recorded during pattern reversal stimulation. The latency of P100 was measured for each eye stimulated. PD patients with dementia showed significant prolongation of the N200 and P300 latencies of ERP and of the P100 latency of VEP compared with the values in normal subjects and in PD patients without dementia. There was a significant correlation between the N200 latency of ERP and the P100 latency of VEP in PD patients with dementia. The findings indicate that the N200 and P300 latencies of ERP are related to cognitive information processing and also suggest that dysfunction in the central visual system plays a role in abnormal pattern VEP in patients with dementia. Furthermore, the disturbance of early sensory processing in response to visual stimuli may roughly parallel the impairment of cognitive information processing in terms of ERP in PD patients with dementia.