A clinical, genetic and audiological study of patients and families with unilateral vestibular schwannomas. II. Audiological findings in 93 patients with unilateral vestibular schwannomas.

Nine-three patients with histologically or radiologically confirmed unilateral vestibular schwannomas were recruited. Audiological testing for retrocochlear pathology was undertaken. Patients' hospital records were examined for previous audiological and radiological results. The audiometric configuration was designated as one of the following: normal, sloping, low frequency, peak, trough or flat. A sloping sensorineural audiometric configuration was present in 68 per cent of cases. No significant correlation was found between tumour size and average pure tone threshold 500 Hz to 4000 Hz, optimum discrimination score or interaural differences for wave V. Ninety-one per cent of cases had abnormalities on auditory evoked potential; 92 per cent of cases showed abnormalities on stapedial reflex testing. The limitations of audiological testing in the investigation of patients with suspected unilateral vestibular schwannomas are discussed. A protocol for the investigation of such patients is presented.