Vestibular schwannoma: when to look for it?

OBJECTIVES

(1) To compare audiometric parameters in patients with vestibular schwannoma and in those with asymmetric hearing loss from other causes; and (2) to assess proposed screening criteria by comparing published protocols.

METHODS

Audiometric data from 199 vestibular schwannoma patients and 225 non-tumour patients were compared. Eight screening protocols were tested on these 424 patients.

RESULTS

Vestibular schwannoma and non-tumour patients with little or no hearing loss in the unaffected ear were inseparable; however, vestibular schwannoma patients with hearing loss in the unaffected ear had greater audiometric asymmetry, compared with non-tumour patients with the same pattern of hearing loss. The sensitivity of screening protocols varied from 73 to 100 per cent; parallelism was observed between sensitivity and screening rate.

CONCLUSION

As regards vestibular schwannoma screening protocols, the best compromise between sensitivity and screening rate was offered by a criterion comprising either: (1) > or =20 dB asymmetry at two neighbouring frequencies, or unilateral tinnitus, or (2) > or =15 dB asymmetry at two frequencies between 2 and 8 kHz.