청력 손실자의 보청기 착용 전후의 말 지각에서의 변화 |
한우재1, Jont B. Allen2 |
1한림대학교 자연과학대학 언어청각학부 2일리노이대학교 전자컴퓨터공학과 |
A Relationship of Speech Perception and Amplification for
Hearing-Impaired Listeners |
Woojae Han1, Jont B. Allen2 |
1Hallym Univ., Div. of Speech Pathology and Audiology, Chuncheon, Korea 2Univ. of Illinois at Urbana-Champaign, Dept. of Electrical and Computer Engineering, IL, USA |
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Received: November 2, 2011; Revised: December 3, 2011 Accepted: December 13, 2011. Published online: December 31, 2011. |
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ABSTRACT |
Individuals with sensorineural hearing loss (SNHL) are treated with hearing aids and/or a cochlear implant, based on their pure-tone
thresholds and speech perception scores. Although these assistive listening devices do help those individuals communicate in quiet
surroundings, many still have difficulty understanding speech in noisy environments. The purpose of current study is to compare
results of consonant perception when using flat gain (or most comfortable level, MCL) and to see changes in consonant error rate
occurred by hearing impairment after applying a frequency specific amplification.
Twenty American English speakers with mild-to-moderate SNHL were tested. Isolated English consonant-vowel (CV) syllables,
consisting of sixteen consonants followed by the /a/ vowel, were used as stimuli. They were presented monaurally in quiet and at five
different signal-to-noise ratios (SNRs) in speech-weighted noise. To compare the consonant error between ‘no NAL-R amplification’
(flat gain) and ‘NAL-R amplification’ conditions, all subjects were tested in the two conditions. When simulating the NAL-R
condition, its formula was calculated in two steps for each subject, by obtaining the required gain as a function of frequency.
Overall consonant percent errors were decreased with NAL-R correction, compared to the no NAL-R conditions. When we look at the
aided audibility and average consonant errors (or scores) after fitting a hearing aid, hearing-impaired (HI) speech perception seems
better than before wearing the hearing aid. However, there is a significant difference among consonants: some consonants obtain great
benefit from NAL-R and others do not. Also, subjects who have similar pure-tone audibility do not receive the same benefit from the
amplification. We conclude that although current amplification fitting methods can offer positive benefit on average to the speech
perception of HI listeners, they cannot offer equally positive benefits to every consonant and every HI listener. |
Key Words:
Amplification Effect · Consonant Perception · Consonant-Vowel Syllable · Hearing Impairment · NAL-R amplification
· Speech Perception |
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