Programmable hearing aid with multichannel compression.

A portable programmable hearing aid with multichannel compression was constructed with three channels with two independently variable crossover frequencies. The compression knee-point and attenuation in each channel and the two crossover frequencies can be programmed from a separate programming unit. Speech discrimination for seven subjects with sensorineural hearing loss was evaluated, comparing each subject individually in three different cases--equalization, multichannel compression and the subject's own conventional hearing aid. Each subject wore each aid for about a week in his/her own environment and was then tested. The following speech discrimination tests were used: monosyllabic phonetically balanced words with and without background noise, nonsense syllables in quiet, and a constant test in quiet and in noise. The study showed that some patients with sensorineural hearing loss accompanied by recruitment can double their speech discrimination by using a hearing aid with multichannel compression.