ANALYSIS OF PATTERN-REVERSAL VISUAL-EVOKED POTENTIALS (PRVEPS) BY SPLINE-WAVELETS

In this study, the pattern-reversal visual evoked potentials (PRVEP's) collected from normal and demented subjects are investigated by apply ing the quadratic spline wavelet analysis. The data are decomposed int o six octave frequency bands. For quantitative purposes, the wavelet c oefficients in the residual waveform representing the delta-theta band activity (0-8 Hz) are explored to characterize the (N70-P100-N130) co mplex. Specifically, the coefficients corresponding to the location of N70, P100, and N130 peaks are investigated for their sign in order to test whether they represent a consistent (N70-P100-N130) complex in t he averaged waveform. Waveforms with normal latency (N70-P100-N130) co mplex are observed to have positive second, negative third, and positi ve fourth coefficients in amplitude in their residual scale standing f or the delta-theta (0-8 Hz) band activity. The method allows for the a nalysis of oscillatory-phase behavior of the normal and pathological P RVEP's in their delta-theta band based on a few quantitative measures consistent with the time-frequency occurrence of the major components of the evoked potential.