LONGITUDINAL-STUDY OF BRAIN-STEM AUDITORY-EVOKED RESPONSES IN 87 NORMAL HUMAN-SUBJECTS

We evaluated the reproducibility of brainstem auditory evoked response s (BAERs) in 87 normal individuals in a longitudinal study by estimati ng the correlation coefficients and variability of the interpeak inter vals and the V/I amplitude ratio between trials on the same day and be tween sessions spaced 2 years apart. The highest correlation coefficie nts occur for the I-V interpeak interval between trials on the same da y. The coefficients for the I-III and III-V intervals are lower, due t o the variability of wave III. The correlations between ears done on t he same day are lower still and are similar to measures obtained from the same ear at a 2-year interval. BAERs are more variable than previo usly believed between ears and over time, but not in a manner that is clinically significant and can be used longitudinally as a measure of neurologic disease. Finally, we provide the sample size required to de tect a significant change in interpeak intervals.