Clinical significance of positive summating potential in Menière's disease.

The positive summating potential (+SP) in Menière's disease was compared with that in normal ears and in cochlear deafness of other origin than endolymphatic hydrops in order to assess a specificity of the +SP in Menière's disease. The +SP was recorded in 21 of 47 Menière ears (45%) on stimulation with 8-kHz tone bursts, whereas the +SP was recorded in none of 10 normal-hearing ears and in 1 of 28 ears with cochlear deafness of other origin than endolymphatic hydrops (4%). The incidence of the +SP in Meniére's disease was higher on stimulation with 8-kHz tone bursts than with 4-, 2- and 1-kHz tone bursts and clicks. No correlation between SP amplitudes recorded with 2- and 8-kHz tone bursts was found. The results suggest that Menière's disease may involve a pathophysiological condition which allows the +SP to be frequently recorded.