Assessment of P300 latencies for individual EEG responses employing an adaptive correlating filter

Correlations between latencies of P300 components in evoked potentials and reaction times were investigated in two normal subjects. The subjects were required to perform choice reaction tasks, responding to particular tones among three tones with different frequencies. EEGs were recorded at the Pz region monopolarly. Latencies of P300 for individual EEG responses were measured employing an adaptive correlating filter. Cross-correlation coefficients between the second templates employed to identify P300s and individual responses for the subjects ranged from 0.623 to 0.997, with the mean value being 0.931. The correlation coefficient between latencies of P300 and reaction times for the subjects was 0.659. Thus, the adaptive correlating filter was proved to be useful in psychophysiological studies.