Digital noise reduction: outcomes from laboratory and field studies

Area of Science:

• Audiology
• Signal Processing
• Human-Computer Interaction

Background:

• Hearing aids increasingly incorporate digital noise reduction (DNR) to improve user experience.
• The effectiveness of DNR schemes, particularly concerning onset time, requires thorough investigation.

Purpose of the Study:

• To evaluate the impact of a commercial hearing aid's digital noise reduction (DNR) scheme.
• To assess the influence of varying DNR onset times (4, 8, 16 seconds) on user perception.
• To compare DNR performance against a DNR-off condition and a multi-memory setting.

Main Methods:

• A double-blind study with 25 participants evaluated five conditions: DNR-on (3 onset times), DNR-off, and a multi-memory condition.
• Participants underwent at-home trials followed by laboratory-based speech perception tests and subjective ratings.
• Measures included speech perception, ease of listening, listening comfort, sound quality, and self-reported aversiveness.

Main Results:

• Laboratory speech perception tests showed no significant effect of DNR, regardless of visual cues.
• DNR-on conditions were rated significantly easier for listening compared to DNR-off.
• The 4-second onset time resulted in lower listening comfort ratings than the 8-second onset or DNR-off. Self-report indicated higher aversiveness with DNR-off.

Conclusions:

• Digital noise reduction (DNR) in hearing aids can enhance the ease of listening experience.
• Onset time is a critical factor influencing listening comfort, with slower onset times potentially being more comfortable.
• While DNR may not improve objective speech perception, it can reduce subjective listening aversiveness.