OBJECTIVETo compare the sex differences on brain stem auditory evoked potentials (BAEP) and P300 in the elderly patients with mild cognitive impairment (MCI) and the patients with Alzheimer's disease (AD).

METHODSThirty-eight elderly patients with MCI, 26 cases of AD and 20 health controls (HC) were examined with BAEP, P300 . Sex difference of the variables was compared inter-and intra-groups.

RESULTSSignificant sex differences of BAEP were found in the latency period wave III, V of left side in the MCI group (P <0.01), in the latency period wave IV, V of left side in HC group (P<0.01), and no such differences were found in AD group. The females had longer latency period in P300 measurement than males in MCI group (P <0.01), but there were no significant differences within AD or HC groups. The males showed significant differences in wave I, II in left side between the MCI and AD groups. The males also showed significant difference in wave I, III approximate, equals V in left side, wave IV in right side between AD and HC groups, and so did the females in wave I approximate, equals V in both sides. The males had significant difference in the left wave III, IV and right wave I, IV, V between MCI and HC groups, and so did the females in right side wave I, II, V. In P300, longer latency waves were found in AD group than in MCI group. Both sexes showed significant differences in the latency of Fz, Cz, Pz between AD and HC groups, but no significant differences were found in the latency of Fz, Cz, Pz in the females between the MCI and HC groups.

CONCLUSIONSex differences were found in the examination of both BAEP and P300 in MCI group, but not in AD group. The people of same sex have different expression of BAEP and P300 among MCI, AD and HC groups, suggesting the sex difference should be considered in the differential diagnosis.