Auditory brainstem responses to single-slope stimuli. The influence of steepness and polarity.
Click polarity has little influence on brainstem potentials. We applied an auditory stimulus similar to a step function generated in a closed acoustic system. The influence of stimulus onset steepness (comprising rise time and intensity) on wave V latency and amplitude was investigated. A remarkable latency prolongation was observed for condensation (C) compared with rarefaction (R), if a sharp bend at the foot of the slope was avoided. The C latency lag was nearly the amount of rise time. The effect can be explained by cochlear travel time. Wave V amplitude for R slopes was significantly enhanced. At high intensity and short rise time, it reached twice the values found with C slopes, or with clicks of either polarity. Although the explanations found are not yet satisfactory, a clinical application in cochlear diagnosis is predictable.
Gerull
G
G
E.N.T. Clinic Charlottenburg, Free University of Berlin, Germany.
Mrowinski
D
D
Janssen
T
T
Anft
D
D
D000328:Adult; D001300:Audiometry, Evoked Response; D001933:Brain Stem / Q000502:physiology*; D005072:Evoked Potentials, Auditory; D006801:Humans; D008144:Loudness Perception / Q000502:physiology; D008875:Middle Aged; D010898:Pitch Perception / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values