[The value of cognitive evoked potentials in the diagnosis of senile dementia and dementia of Parkinson disease].

P300 latency is often delayed in dementia but some authors have questioned its interest in clinical practice, because of the relatively low specificity and sensibility of the method. Therefore, we studied numerous parameters (latency, duration, amplitude and surface) of N100, N200 and P300 waves in patients with senile dementia, patients suffering from Parkinson's disease with dementia and non demented elderly patients. Using discriminant analysis, more than 90% of the patients were correctly classified. This method could thus be contributive in clinical practice.