Benefit of Amplification at Low Input Levels in Normal-Hearing Listeners

Area of Science:

• Audiology
• Acoustics
• Human-Computer Interaction

Background:

• Hearing devices like hearables and hearing aids are increasingly used by people with normal hearing.
• The advantages of amplification for individuals with normal hearing are not well understood.

Purpose of the Study:

• To investigate the effects of amplification on hearing thresholds, speech intelligibility, and listening effort in normal-hearing listeners.
• To compare outcomes between open ear, acoustically transparent, and amplified conditions.

Main Methods:

• Forty-four young adults with normal hearing participated in two experiments.
• Three conditions were tested: open ear, 0 dB gain (acoustic transparency), and 15 dB gain.
• Speech intelligibility was measured using the Oldenburg Sentence Test, and listening effort was assessed using Adaptive CAtegorical Listening Effort Scaling (ACALES).

Main Results:

• A nominally transparent device (0 dB gain) led to disadvantages including elevated hearing thresholds, reduced speech intelligibility, and increased listening effort.
• 15 dB amplification partially restored hearing thresholds, fully restored speech intelligibility, and reduced listening effort compared to the unaided condition.
• Hearing aid microphone noise limited benefits at low input levels.

Conclusions:

• Amplification can provide significant benefits for normal-hearing listeners at low speech levels, especially when considering listening effort.
• These findings suggest that amplification strategies may be beneficial beyond traditional audiological applications.
• Further research should explore real-world listening conditions and potential benefits for hearing-impaired individuals.