P1 Amplitude Across Replicates: Does Measurement Method Make a Difference?

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Speech and Hearing Sciences


Purpose: Most cortical auditory evoked potentials instruments provide a "default" peak-to-baseline (P-B) amplitude and a means for obtaining a peak-to-trough (P-T) measure. This study investigated the sensitivity of these two measures in assessing the effects of repeated runs on the P1 component of the electrophysiological response. Methods: Cortical auditory evoked potentials were recorded on 30 normal hearing young adults. Three stimuli were used: an 80-millisecond synthetic /da/and a 1 kHz tone burst of 40- and 80-millisecond durations. Stimuli were presented at 60 dB normal hearing level in a counterbalanced order. Three serial replicates were obtained for each stimulus. P1 amplitude and latency were measured. Results: The P-T amplitudes diminished significantly (P < 0.01) from replicate 1 to replicate 3 for each of the three stimulus types, but P-B amplitudes did not. P1 latency findings were consistent with effects shown by diminished P-T amplitude data in which latency increased significantly (P = 0.024) from replicate 1 to replicate 3 for one stimulus (40-millisecond tone). Conclusions: The P-T amplitude measurement method identified significant decrements in amplitude because repeated runs were obtained, whereas the P-B method did not. These findings suggest that a P-T method is more sensitive to some P1 electrophysiological activity than is a P-B measure.

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Journal of Clinical Neurophysiology





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