In patients with peripheral vertigo the presence of an asymmetrical hearingloss is an important lateralizing sign, having both diagnostic and prognostic significance. In a consecutive series of 83 patients undergoing retro-labyrinthine vestibular nerve section for uncontrolled vertigo, asymmetrical hearing loss was associated with an 83 percent incidence of complete control of vertigo and a 49 per cent incidence of complete relief from dysequilibrium. In the absence of a lateralizing hearing loss, the figures were 50 per cent and 24 per cent respectively (p<0.01 and p<0.05). The explanation for this finding may be that the presence of a hearing loss is more often associated with an exclusively peripheral disorder (controllable by peripheral surgical ablation), whereas inpatients with symmetrical hearing there may be an unrecognized central or contralateral pathology resulting in lesseffective results from a unilateral peripheral surgical approach. The bithermal caloric test did not give such useful diagnostic or prognostic information.
