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Effects of
audiometric configuration on the auditory brainstem response
Abstract
Evidence reported in the literature indicates that wave I of the auditory
brainstem response is influenced by cochlear contributions from a more basal
area of the cochlea than is wave V. This phenomenon is invoked to explain
different latency-intensity function patterns of waves I and V and the I-V
interval for four types of cochlear hearing loss.
In high frequency hearing losses wave V is delayed at low intensities. Wave I
tends to be delayed at all intensities and by a greater amount than wave V. The
I-V interval is often reduced with the effect maximal at higher intensities.
Low frequency hearing losses tend to cause early wave V latencies at low
intensities. Wave I latencies are normal. The I-V interval is therefore reduced
at lower intensities.
Flat hearing losses produce normal latency-intensity functions.
High-frequency notched audiograms are almost always associated with delayed
wave V but early wave I latencies. The I-V interval is therefore significantly
prolonged with the effect maximal at low intensities.
The variability of the I-V interval as a function of audiometric
configuration indicates that it is not a pure measure of central conduction
time.
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