Bilaterally Recorded Auditory Brainstem Responses to Monaural Stimulation: Latency and Amplitude Differences in Normal Subjects

Abstract

Ipsilaterally and contralaterally (forehead-mastoid) recorded ABRs to monaurally administered clicks at 90 dB nHL were compared in 16 young normal-hearing female subjects (32 ears). The comparisons were made with regard to latencies and amplitudes of waves I, III and V, and the results concern group statistics. Wave I was recordable in the contralateral derivation in less than 50% of the cases. The amplitudes of waves I and III were significantly smaller, and the latency of wave III significantly shorter (by an average of 0.15 ms) in the contralaterally recorded ABR. There was a tendency for wave V to diminish and to lag in the contralateral recording; however, there were no statistically significant differences in wave V amplitude and latency between the two sides. Nor was there found to be any significant variability differences concerning wave III and wave V latencies between the two derivations. The dominance of the wave V peak-to-peak amplitude was established in both recordings. Two concluding computations showed that there were no differences between right and left ear stimulation, and no differences between recordings performed with the ground electrode applied to the nasion or to the sternum.