Directional benefit is present with audiovisual stimuli: limiting ceiling effects

Area of Science:

• Audiology
• Speech Perception
• Hearing Aid Technology

Background:

• Previous research indicates that the benefit of directional microphones in hearing aids diminishes as speech recognition approaches its maximum, especially in favorable listening conditions.
• This suggests that directional microphone benefit might be limited in environments with visual cues and good signal-to-noise ratios (SNRs).

Purpose of the Study:

• To evaluate the directional benefit of a bilateral beamformer microphone system in real-world signal-to-noise ratios (SNRs) ranging from +3 to +12 dB.
• To assess directional benefit using auditory-visual stimuli to simulate realistic listening scenarios.

Main Methods:

• Sentence recognition was tested in three SNRs and two reverberation levels (low and moderate).
• Participants' sentence recognition was evaluated using both omnidirectional and bilateral beamformer microphone modes.
• Fifteen adults with hearing loss, specifically those with significant difficulty understanding speech in noise, were included in the study.

Main Results:

• A significant benefit from the bilateral beamformer was observed, ranging from approximately 20-28 percentage points.
• This benefit was consistent across all tested SNRs (+3 to +12 dB) and in both low and moderate reverberation conditions.

Conclusions:

• The findings support the use of bilateral beamformers for hearing aid users with poor speech recognition in noise.
• Bilateral beamformers provide significant directional benefit even in relatively favorable SNRs and when visual cues are present.