Individual differences in auditory electric responses: comparisons of between-subject and within-subject variability. I. Absolute latencies of brainstem vertex-positive peaks.

Seven subjects were tested, each on eight separate sessions, for brainstem auditory evoked responses to monaural right, monaural left, and binaural stimulus presentations. Comparisons of between-subject vs. within-subject variability of the absolute latencies of vertex-positive peaks expressed in terms of the coefficient of variation indicate that: within-subject stability is greater than between-subject stability for the five brainstem peaks; between-subject variability shows significant differences due to peak but not to ear of presentation; within-subject variability shows significant differences due to both peak and ear; comparisons of within-subject variability over time show significant differences due to peak but not to time; patterns of individual variation within the brainstem series are characterized by increases in stability of peak latencies over time, and by replicability of stability profiles over time. Other measures of latency and amplitude based on this series of responses are planned for a subsequent report.