Long-term effects of donepezil on P300 auditory event-related potentials in patients with Alzheimer's disease.

The P300, one of the cognitive event-related potentials (ERPs) of the cerebral cortex, reflects the functioning of the neurochemical system involved in cognitive processes. We investigated clinical significance of the components of auditory P300 ERPs, in comparison with neuropsychologic tests including the Mini-Mental State Examination and the Japanese version of the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-J cog), for evaluating of the effect of donepezil (DPZ) (5 mg daily for 6 months), an acetylcholinesterase inhibitor, in patients with Alzheimer's disease (AD). Reduction of P300 latency associated with a parallel improvement of ADAS-J cog scores was observed after administration of 5 mg/day of DPZ in patients with AD. P300 latency gives very useful information on the progression of AD, especially in the longitudinal follow-up of patients with AD during treatment with DPZ acting on cholinergic pathways.