Auditory brainstem response in obstructive sleep apnea.

Auditory brainstem response (ABR) has been used by several investigators to study the role of the brain stem in the pathophysiology of obstructive sleep apnea (OSA). These studies have produced conflicting results. We studied 27 preoperative OSA patients and 17 controls using click stimuli presented at a slow (11.7/second) rate and at a fast (57.7/second) rate. ABR was repeated postoperatively in 18 patients. There were no statistically significant differences in the ABRs of preoperative OSA patients when compared with the control group. However, the preoperative recordings showed statistically significant prolonged latencies for wave III (p less than 0.01) and interpeak latency (IPL) I-III (p less than 0.01) when compared to postoperative recordings. Rapid-rate testing was not helpful. Although normal sleep does not cause ABR abnormalities, the pathological sleepiness seen in OSA patients may cause brainstem dysfunction manifested by prolonged ABR latencies. These abnormalities may resolve with treatment of OSA.