Changes of the Korean Consonant-Vowel Syllabic Recognition Scores According to the Compression Threshold Control of Multi-Channel Hearing Aid

Purpose: While adjusting the compression threshold (CT) of low and high frequency bands of multi-channel hearing aids in noise, we tried to evaluate any changes in Korean consonant-vowel (CV) syllabic recognition scores, sound quality, and loudness of noise with white noise. Methods: A total of twenty one subjects with hearing loss (mean age of 66.2 years) participated voluntarily. Their pure-tone average was 46.0 dB HL and the word recognition score was 72.1%. The CTs of low/ high frequency bands were adjusted to 50/50 dB SPL, 50/65 dB SPL, 65/50 dB SPL and 60/65 dB SPL in multi-channel hearing aids. While presenting white noise to the non-test ear, Korean CV syllables were presented to the test ear to evaluate the recognition scores, clarity of conversational speech, and loudness of noise. The intensity of CV syllables presented to the subject was 50 dB HL, and the signal-to-noise ratios (SNRs) were 5 dB and 10 dB. Results: First, when the CT of low/high frequency bands was adjusted to 50/50 dB SPL, the CV syllabic recognition scores were higher compared to 65/50 dB SPL. Second, in the noise environment, the clarity of conversational speech, and loudness of the noise did not have any difference regardless of levels of CT. Conclusion: Based on current findings, the frequency bands setting of CT in the multi-channel hearing aids might provide changes to recognize Korean speech sounds, which may affect the adjustment of frequency band CT from multichannel hearing aids in the future.