[Manifestations of inactivity in unilateral hearing aid management of patients with a high degree of hearing loss].

Concluding from audiometrical practice using hearing aids unilaterally we could find an inactivity of the unused contralateral ear. We have investigated if it is possible to measure this inactivity by common psychoacoustic methods. We tested 92 persons with advanced combined hearing loss. We had to state that the inactivity is not measurable by mean tone hearing loss according to HAIC (0.5, 1 and 2 kHz), the percentage hearing loss according to Fowler-Sabine, the percentage of hearing loss calculated by speech-audiogram according to Boenninghaus and Röser 1973 and the value of hearing loss for speech (a1). It is only a big discrimination loss that points to the presence of inactivity. The discrimination loss was compared in two groups concerning "used" and "unused" ears. We could clearly measure the biggest discrimination loss in the group of unused ears. The clinical consequences were discussed.