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Comparison of the Auditory‐Evoked Brainstem Response Wave I to Distortion‐Product Otoacoustic Emissions Resulting From Changes to Inner Ear Blood Flow
Author(s) -
Telischi Fred F.,
Mom Thierry,
Agrama Mark,
Stagner Barden B.,
Ozdamar Ozcan,
Bustillo Andres,
Martin Glen K.
Publication year - 1999
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-199902000-00003
Subject(s) - audiology , otoacoustic emission , auditory brainstem response , amplitude , brainstem , superior olivary complex , blood flow , acoustics , medicine , cerebral blood flow , anesthesia , hearing loss , physics , cochlear nucleus , cardiology , optics
Objective/Hypothesis : Examine and compare in detail the time courses of the auditory brainstem response (ABR) wave I amplitude and latency to the distortion‐product otoacoustic emission (DPOAE) amplitude and phase measured in the rabbit model following deliberate obstruction of cochlear blood flow (CBF). Methods : Using a posterior fossa craniotomy in five rabbits, the internal auditory artery (IAA) was compressed with a probe. ABR and otoacoustic emission were continuously monitored before, during, and after the compressions. Results : ABR wave I amplitudes demonstrated measurable decreases at a mean of 28.3 s after IAA compression, whereas DPOAE amplitudes decreased after a mean of 14.8 s. Wave I latencies began to increase at a mean of 18.3 s after occlusion, while DPOAE phase measures changed after a mean of only 4.8 s following IAA compression. The time‐course patterns were similar for the amplitudes of both ABR wave I and DPOAE. Conclusions : ABR wave I amplitude follows a similar, though delayed (by approximately 10 s) time‐course pattern to that of the DPOAE following IAA compression. The implication of these findings for intraoperative auditory monitoring is that changes in many currently employed measures will lag actual surgically induced alterations in CBF by at least 20 to 30 s.