Increased N200 and P300 latencies in cognitively impaired elderly carrying ApoE ε-4 allele

Abstract

Objective: To compare the results of neuropsychological tests, evoked potentials N200 and P300 and polymorphisms of ApoE and BDNF rs6265 between patients with normal cognition and those with mild cognitive impairment (MCI) and Alzheimer's dementia (AD).

Methods: This is a cross-sectional study of elderly individuals with normal cognition and those with MCI and AD, who were submitted to evoked potential tests (N200 and P300) by means of hearing stimuli based on the auditory oddball paradigm. Genotyping was obtained by using the real-time PCR technique.

Results: Sixty-five patients were evaluated as follows: 14 controls, 34 with MCI and 17 with AD. N200 latency and P300 latency and amplitude were not associated with MCI and AD diagnosis. Patients with cognitive impairment (MCI or AD) showed increase in the latencies of P300 and N200. BNDF gene was not associated with cognitive impairment.

Conclusion: Latencies of N200 and P300 increased in cognitively impaired patients with the presence of ApoE ε-4 allele.

Keywords: Alzheimer's disease; apolipoproteins E; auditory evoked potentials; brain-derived neurotrophic factor; mild cognitive impairment.