BAEP subcomponents and wave form--relation to click phase and stimulus rate.
The latency distributions of normal brain-stem auditory evoked potential (BAEP) components elicited by condensation (C) and rarefaction (R) clicks at 10 and 50 Hz were found to be double- or multi-peaked for II (10 and 50 Hz), III (50 Hz), IV (10 and 50 Hz) and V (10 Hz). A bifid component III was found in 3.5% (10 Hz) and 7.4% (50 Hz) of BAEPs. A bifid II and triple IV/V configuration were occasionally noted. The prevalences of the different IV/V complex configurations were significantly dependent upon click phase and rate. These results suggest that several subcomponents might participate in the generation of the single BAEP components and that a single generator may contribute to different BAEP components in different subjects. Early subcomponents between I and II (Ib) were found in 13% of 10 Hz BAEPs and 27% of 50 Hz BAEPs (P = 0.002) and the latency distribution of Ib seemed to be bimodal. Ib/I relative amplitude frequently increased with 50 Hz stimulation. We suggest that the generator of Ib is partially cochlear (CM) and partially neural (equivalent to N2 of the ECochG-AP) in origin. The existence of subcomponents must be recognized in clinical use of BAEPs both to avoid misinterpretation and to decrease the normal variability in monophasic click evoked BAEP studies.
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D000161:Acoustic Stimulation / Q000379:methods*; D000293:Adolescent; D000328:Adult; D001933:Brain Stem / Q000502:physiology*; D005072:Evoked Potentials, Auditory; D006801:Humans; D008875:Middle Aged; D011930:Reaction Time; D013997:Time Factors