Speech intelligibility in noisy environments with one- and two-microphone hearing aids

In this study speech intelligibility in background noise was evaluated with 10 binaural hearing-aid users for hearing aids with one omnidirectional mi crophone and a hearing aid with a two-microphone configuration (enabling an omnidirectional as well as a directional mode). Signal-to-noise ratio (SNR ) measurements were carried out for three different types of background noi se (speech-weighted noise, traffic noise and restaurant noise) and two kind s of speech material (bisyllabic word lists and sentences). The average SNR improvement of the directional microphone configuration relative to the om nidirectional one was 3.4 dB for noise presented from 90 degrees azimuth. T his improvement was independent of the specific type of noise and speech ma terial, indicating that one speech-in-noise condition may yield enough rele vant information in the evaluation of directional microphones and speech un derstanding in noise.