[Parkinson disease and cognitive evoked potentials].

Long latency auditory evoked potentials were recorded in 50 patients with Parkinson's disease, some case were also investigated by the Rapid Evaluation of Cognitive Functions test (RECF) and Trail Making A test (TMA). Latencies of P2, N2 and P300 waves were longer in the parkinsonian group than in a control group matched for age. Latencies of N2 and P300 waves were correlated significantly with scores for RECF and TMA presumed to be sensitive to organic brain lesions. On the other hand no significant correlation was found between RECF and P1 and P2 latencies. In addition, correlation was lacking between Verbal Automatism test scores, presumed to be resistant to organic brain lesions, and P300 wave latencies. Cognitive evoked potential (CEP) latency increases with age in normal subjects. In the parkinsonian group the coefficient of correlation between these two factors was lower but still significant. The parkinsonian patients with dementia as defined by DSM III criteria, or an RECF score of less than 46, showed longer N2 and P300 latencies but no significant difference in N1 and P2 latencies. In contrast, comparison of P300 and N2 wave latencies in depressed and non-depressed parkinsonian patients failed to show any significant difference. The bilateral akinetic forms had marked lengthening of P300 wave latencies and a lower TMA score. Neither the duration of the disease, type of treatment, duration of L-Dopa therapy significantly influenced the latency of cognitive event-related potentials.