The effect of acoustic neuroma removal on hearing in the contralateral ear

22 patients with unilateral acoustic neuromas were assessed audiometrically pre- and post-operatively. A high proportion (36%) were found to have a hearing loss of 10 dB or more (6 frequency average) in the contralateral ear in the post-operative period. The evidence points to a cochlear site of the loss, and serial audiograms suggest that the hearing deteriorates in the immediate post-operative period. Follow-up audiometry at three months or more showed that the hearing recovered to pre-operative levels. The possible mechanism of the hearing loss is discussed.