Acoustic neuroma: deterioration of speech discrimination related to thresholds in pure-tone audiometry.

Pure-tone and speech audiometry were performed in 231 patients with a unilateral acoustic neuroma. Tumor sizes were obtained through imaging. Audiometric parameters, such as the mean pure-tone thresholds, the maximum discrimination, the slope of the speech audiogram, the roll-over index and the difference between the speech reception threshold and the Fletcher index, were studied and compared with data in the literature. Results showed that patients with an acoustic neuroma have worse speech discrimination than can be expected from the pure-tone audiogram. However, the results presented here indicate that hearing impairments nowadays are not as severe as those described in earlier studies. More patients with a unilateral acoustic neuroma are detected, including even those with a minor hearing impairment. The roll-over index is not characteristic for patients with an acoustic neuroma.