The effects of changes in head angle on auditory and visual input for omnidirectional and directional microphone hearing aids.

Improving the signal-to-noise ratio (SNR) for individuals with hearing loss who are listening to speech in noise provides an obvious benefit. Although binaural hearing provides the greatest advantage over monaural hearing in noise, some individuals with symmetrical hearing loss choose to wear only one hearing aid. The present study tested the hypothesis that individuals with symmetrical hearing loss fit with one hearing aid would demonstrate improved speech recognition in background noise with increases in head turn. Fourteen individuals were fit monaurally with a Starkey Gemini in-the-ear (ITE) hearing aid with directional and omnidirectional microphone modes. Speech recognition performance in noise was tested using the audiovisual version of the Connected Speech Test (CST v.3). The test was administered in auditory-only conditions as well as with the addition of visual cues for each of three head angles: 0 degrees, 20 degrees, and 40 degrees. Results indicated improvement in speech recognition performance with changes in head angle for the auditory-only presentation mode at the 20 degrees and 40 degrees head angles when compared to 0 degrees. Improvement in speech recognition performance for the auditory + visual mode was noted for the 20 degrees head angle when compared to 0 degrees. Additionally, a decrement in speech recognition performance for the auditory + visual mode was noted for the 40 degrees head angle when compared to 0 degrees. These results support a speech recognition advantage for listeners fit with one ITE hearing aid listening in a close listener-to-speaker distance when they turn their head slightly in order to increase signal intensity.