Multi-channel compression and speech intelligibility in industrial noise

Area of Science:

• Audiology
• Hearing Science
• Occupational Health

Background:

• Industrial noise poses significant challenges to speech intelligibility.
• Hearing loss, particularly high-frequency sensorineural hearing loss, exacerbates difficulties in noisy environments.
• Digital hearing aids offer various compression strategies to aid hearing in noise.

Purpose of the Study:

• To evaluate the impact of different hearing aid compression modes on speech intelligibility in industrial noise.
• To compare speech recognition performance across compression limiting, BILL (low-frequency only), and TILL (high-frequency only) settings.
• To assess noise exposure levels associated with each compression mode.

Main Methods:

• Thirteen participants with high-frequency sensorineural hearing loss were tested.
• Speech intelligibility was measured using CID W-22 monosyllabic words in industrial noise.
• Hearing aids were programmed to three compression modes: compression limiting, BILL, and TILL.
• Word recognition was also assessed in quiet.
• Time-weighted average (TWA) noise exposures were calculated for each condition.

Main Results:

• Word identification scores were highest in quiet (80.9%).
• Among noise conditions, TILL compression yielded the highest mean speech intelligibility score (52.4%), while BILL compression yielded the lowest (39.7%).
• Projected 8-hour amplified TWAs were 94 dBA for TILL and 104 dBA for linear and BILL configurations.

Conclusions:

• TILL compression significantly enhances speech intelligibility in moderately high industrial noise compared to BILL compression.
• The TILL mode offers the dual benefit of improved audibility and reduced noise exposure for hearing aid users in industrial settings.
• Hearing aid programming with high-frequency compression is a viable strategy for improving communication in noisy workplaces.