Latencies of ABR (waves III and V) to binaural clicks: effects of interaural time and intensity differences.
Auditory brainstem responses to monaural clicks and to binaural clicks delivered with interaural time differences of 0.5 and 1 ms (delayed clicks in left ear) and interaural intensity differences (right ear minus left ear) of 0, +/- 10, +/- 20, and +/- 30 dB were recorded bilaterally in 7 normal subjects. Latencies of wave III and wave V were studied as functions of click intensity difference for each of the two time-of-onset differences. As the intensity difference was gradually varied from +30 to -30 dB, the latencies were seen to shift (with constant III--V interval) from those of a monaural right-ear (non-delayed clicks) response to those of a monaural left-ear (delayed clicks) response by 0.5 and 1 ms. In all subjects this shift occurred in the 20-dB interval between equal intensity and 20-dB lagging-click dominance, and almost always most of the shift took place in either of the two 10-dB subintervals. Occasionally double-peaked waves appeared in the 20 dB-interval. Binaural ABRs may become useful for diagnosis in patients with signs of brainstem disorder but with normal-hearing and normal audiometric findings including monaural ABR, as such patients have been found to shift their latencies more slowly with varying interaural intensity difference.
D000328:Adult; D001299:Audiometry / Q000379:methods*; D001300:Audiometry, Evoked Response / Q000379:methods*; D001307:Auditory Perception / Q000502:physiology*; D001933:Brain Stem / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008144:Loudness Perception / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*