Normal audiologic presentations in patients with acoustic neuroma: An evaluation using strict audiologic parameters

Although several studies have previously reported on patients presenting wi th "normal" audiologic parameters in acoustic neuroma, the present study is , to our knowledge, the first to exclusively examine in detail cases involv ing exceptionally stringent objective audiometric features. Of 369 patients with acoustic neuroma who were operated on between April 1980 and April 19 97 by our group, 10 had strictly normal hearing, defined as follows: (1) pu re-tone average < 20 dB; (2) speech discrimination score > 90%; and (3) int eraural differences less than or equal to 10 dB at every hertz level. A hig h level of audiologic functioning was found to significantly lower the sens itivity of auditory brainstem response in the detection of acoustic neuroma . Magnetic resonance imaging was the only preoperative test exhibiting 100% sensitivity in this setting, Thus, a high level of clinical suspicion appe ars warranted in any case involving unexplained unilateral audiovestibular symptoms-including those instances in which strictly normal hearing paramet ers exist and are associated with negative auditory brainstem response find ings.