Directional microphone systems are typically used to improve hearing aid users' understanding of speech in noise. However, directional microphones also increase internal hearing aid noise. The purpose of this study was to investigate how varying directional microphone bandwidth affected listening preference and speech-in-noise performance.
Ten participants with normal hearing and 10 participants with hearing impairment compared internal noise levels between hearing aid memories with 4 different microphone modes: omnidirectional, full directional, high-frequency directionality with directional processing above 900 Hz, and high-frequency directionality with directional processing above 2000 Hz. Speech-in-noise performance was measured with each memory for the participants with hearing impairment.
Participants with normal hearing preferred memories with less directional bandwidth. Participants with hearing impairment also tended to prefer the memories with less directional bandwidth. However, the majority of participants with hearing impairment did not indicate a preference between omnidirectional and directional above 2000 Hz memories. Average hearing-in-noise performance improved with increasing directional bandwidth.
Most participants preferred memories with less directional bandwidth in quiet. Participants with hearing impairment indicated no difference in preference between directional above 2000 Hz and the omnidirectional memories. Speech recognition in noise performance improved with increasing directional bandwidth.