Visual evoked potentials in early Alzheimer's dementia: an exploratory study.

Topographical maps of visual evoked potentials (VEPs) were recorded from 10 possible Alzheimer's disease (AD) patients and 10 control subjects. The purpose of the study was to determine if the two types of VEPs could function as a diagnostic screening for AD. Results of the statistical analysis did not reveal any latency differences between VEPs for the components elicited by either the pattern shift visual evoked potential (PSVEP)--or flash visual evoked potential (FVEP)--elicited components for AD patients compared with the control subjects; however, the information provided insight into results that are frequently lost with conventional evoked potential data. Statistically significant differences in amplitude were found between the P1 and the N2 of the PSVEP at 124, 126, and 130 ms, and at 116 ms for the FVEP.