Since the first published description of the auditory brainstem response (ABR) by Jewett and Williston in 1971, there have been hundreds of published works on both clinical and perioperative ABR applications. Intraoperatively, the eighth cranial nerve is in jeopardy of being injured during microvascular decompression surgery. Auditory function preservation is enhanced by ABR monitoring during resection of small vestibular schwannomas. Surgical manipulation of the brainstem during excision of large cerebellar pontine angle tumors has been monitored by ABR to detect any deleterious effect to the brainstem auditory pathways that might occur.

Interpretation criteria for the auditory brainstem response is available from several published guidelines that are based on the literature mentioned above but what are the "other" factors we encounter daily in the operating room that we need to consider as well?