Externalization of Speech When Listening With Hearing Aids

Area of Science:

• Audiology
• Psychoacoustics
• Hearing Science

Background:

• Subjective reports suggest hearing aids can alter sound externalization and perceived sound distance.
• Understanding these effects is crucial for improving hearing aid user experience and spatial hearing perception.

Purpose of the Study:

• To investigate how different hearing aid styles affect sound externalization and perceived sound distance.
• To quantify the impact of microphone position and dome type on spatial hearing perception.

Main Methods:

• Experiment involving young adults with normal or impaired hearing fitted with adjustable hearing aids.
• Participants rated perceived sound externalization using a scale from -10 (in-head) to 10 (at loudspeaker).
• Variations included behind-the-ear vs. in-ear microphones and closed vs. open dome types.

Main Results:

• Hearing aids generally reduced perceived sound distance and increased "in-the-head" sound perceptions compared to unaided listening.
• The most significant disruption occurred with closed domes and behind-the-ear microphones.
• Acoustical data suggested increased low-frequency levels and ambiguous spatial cues contribute to externalization breakdown.

Conclusions:

• Hearing aid use can disrupt the natural perception of sound source location.
• Specific hearing aid configurations (closed domes, BTE microphones) exacerbate these auditory illusions.
• Further research into acoustic factors influencing externalization is warranted for hearing aid design.