Changes in Speech Recognition Scores and Sound Quality According to Gain Adjustment in High Frequency Bands

Purpose: In this study, changes before and after adjustment in high frequency bands were assessed for aided threshold, psychoacoustic evaluation, word recognition scores (WRSs) in noise and sound quality to aid in electroacoustic adjustment, and to improve the satisfaction of hearing aids. Methods: The subjects were 16 sensorineural hearing impaired (25 ears) with 63.4 years old of mean age, 60.8% WRS and 46.6 months of aided experience. For the experiment, hearing aid gain of highfrequency bands adjusted to preferred gain was increased to a higher level. Aided threshold, Korean version of international outcome inventory for hearing aids (K-IOI-HA), Korean version of profile of hearing aid benefit-quick version (K-PHAB-Q), WRSs in noise for 10 dB and 5 dB signal-to-noise ratio (SNR) and sound quality were subsequently evaluated after two weeks and the results were quantitatively compared before and after gain adjustment in high-frequency bands. Results: This study results in as follows; first, improvement in aided threshold for frequencies above 2.0 kHz was shown. Second, K-IOI-HA and K-PHAB-Q in easy communication and localization categories resulted in significant enhancements. Third, WRS in 5 dB and 10 dB SNR was improved. Fourth, improvements were shown for occlusion and clarity of the sentence in the evaluation of sound quality, but significant results were not shown for sharpness and loudness of noise conditions. Conclusion: With sensorineural hearing loss, a sufficient gain in high frequency bands provides improved satisfaction to hearing aids and enhanced word recognition ability in various listening environments.