Preliminary evaluation of a method for fitting hearing aids with extended bandwidth

Area of Science:

• Audiology
• Hearing Aid Technology
• Speech Perception

Background:

• Hearing aid fitting requires optimizing audibility and sound quality.
• Extended high-frequency response in hearing aids may improve speech perception, especially for high-frequency sounds like /s/ and /z/.
• The CAMEQ2-HF method aims to provide extended high-frequency gains for hearing aids.

Purpose of the Study:

• To conduct a preliminary laboratory evaluation of the CAMEQ2-HF hearing aid fitting method.
• To assess the audibility of extended high-frequency components with CAMEQ2-HF.
• To investigate listener preferences and speech recognition performance with varying bandwidths.

Main Methods:

• Linear filtering was used to implement CAMEQ2-HF gains for speech stimuli at 65 dB SPL.
• Evaluations were conducted with four normal-hearing (NH) and fifteen hearing-impaired (HI) listeners.
• Listeners rated bandwidth preferences for pleasantness and clarity, and performed speech recognition tasks.

Main Results:

• CAMEQ2-HF gains successfully restored audibility of frequencies above 5 kHz.
• Normal-hearing listeners preferred wider bandwidths (7.5-10 kHz) for pleasantness and clarity.
• Hearing-impaired listeners preferred narrower bandwidths for pleasantness but wider bandwidths for clarity.
• Hearing-impaired listeners showed improved performance on the S-test with wider bandwidths (7.5 kHz).
• Vowel-consonant-vowel syllable identification improved with bandwidth for NH listeners but not HI listeners.

Conclusions:

• The CAMEQ2-HF method can make extended high frequencies audible.
• Bandwidth preferences for hearing aids differ between normal-hearing and hearing-impaired listeners.
• Wider bandwidths may benefit speech clarity and specific speech sounds for hearing-impaired individuals.