The effects of reduced cerebrovascular circulation on the auditory brain stem response (ABR).
The effect of decreased anterior (carotid) bloodflow on the auditory brain stem response (ABR) was studied in a group of middle-aged males with angiographically confirmed decreased carotid circulation who were candidates for internal carotid end-arterectomy. Individual and mean latencies from the experimental group were compared to latencies of a control group matched for age, sex, and hearing loss. Mean absolute latency of wave V was significantly longer in the group with decreased anterior circulation when compared to the matched control group. These findings are similar to those from studies examining decreased posterior (vertebrobasilar) circulation. Both the matched control and experimental group were also compared to clinic norms and judged for abnormality. None of the control group ABRs were judged abnormal, after correction for hearing loss, while 29% of the ABRs were judged abnormal from the group with decreased anterior circulation. Postoperative testing was performed 1 week after surgery to determine any immediate effects of revascularization of the ABR. No changes in absolute or interpeak latencies were observed for either ear between pre- and postoperative testing. It is concluded that patients with confirmed decreased cerebrovascular circulation may show prolongation of absolute latency of wave V on ABR testing. Revascularization surgery in these patients appears to have no affect on their ABR within 1 week of surgery.
D000328:Adult; D000368:Aged; D001307:Auditory Perception / Q000502:physiology*; D002545:Brain Ischemia / Q000503:physiopathology* / Q000601:surgery; D001933:Brain Stem / Q000503:physiopathology*; D002340:Carotid Artery Diseases / Q000503:physiopathology; D002544:Cerebral Infarction / Q000503:physiopathology; D002548:Cerebral Revascularization; D005072:Evoked Potentials, Auditory; D006313:Hearing Loss, Central / Q000503:physiopathology*; D006316:Hearing Loss, High-Frequency / Q000503:physiopathology; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology*; D006801:Humans; D002546:Ischemic Attack, Transient / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology; D011930:Reaction Time / Q000502:physiology