SIGNIFICANCE OF FALSE-POSITIVE AUDITORY BRAIN-STEM RESPONSE - A CLINICAL-STUDY

Auditory brainstem response (ABR) is a good screening test for cerebel lopontine angle (CPA) tumors and other retrocochlear diseases. The pat hologic correlates of many cases with positive ABR remain unknown. A t wo-staged clinical study was performed to help us understand the signi ficance of a false-positive ABR. In the first stage, data from 66 pati ents with abnormal ABR were reviewed. Nineteen patients had identifiab le causes for the ABR abnormality, whereas 47 patients had no lesions identified. In the second phase of the study 21 of the 47 patients wer e re-evaluated with a minimum follow-up period of 1 year. A detailed i nterval history was obtained, and the work-up, including imaging studi es, was repeated in an attempt to reach a diagnosis. One patient was f ound to have a CPA tumor, but for nine patients a definite final diagn osis could not be determined. The implications of abnormal ABR and nor mal initial imaging study are discussed, and a plan for the work-up of these patients is suggested.