Complex pattern visual evoked potentials in controls and multiple sclerosis patients

Nontraditional circular checkerboard patterns were used in addition to the standard checkerboard to record visual evoked potentials. Peak analysis was used to determine latency and amplitude values for peaks of the triphasic response (N1, P1, and N2). Although P1s remained fairly constant across patterns, definite trends were seen for the N1 and N2 peaks. These changes had significant effects on the time interval of the triphasic response. Common findings for the MS patients including P1 latency prolongation, decreased peak amplitudes, and, in general, deviations from all of the above-mentioned control trends. The findings suggest that the circular checkerboard pattern is a more effective stimulus than the standard checkerboard and that the N2 peak may be of more diagnostic value than suggested by previous reports