Normal auditory brainstem response in patients with acoustic neuroma.

Auditory brainstem response testing has been a major breakthrough in audiologic screening for acoustic neuroma because of its high degree of sensitivity. Although it is not uncommon for other cerebellopontine angle masses to present with normal ABR findings, reports of eighth nerve tumors with false-negative auditory brainstem response tests are quite rare. A series of 120 acoustic neuromas resected at the University of Michigan was reviewed and revealed two such patients. These two patients presented with asymmetric sensorineural hearing loss and unilateral tinnitus and were found to have completely normal auditory brainstem response. The diagnosis of acoustic neuroma would have been delayed if a comprehensive evaluation had not been pursued.