Acoustic analyses of monosyllabic words which are difficult to discriminate in the high frequency hearing loss

Noh, Heil; Chae, Sayong

Abstract

BACKGROUND AND OBJECTIVES: Speech discrimination testing has been used to evaluate the communication disability, select hearing aid candidacy and appropriate amplification, plan and evaluate aural rehabilitation programs and assist in the determination of the site of lesion. Since the words of speech discrimination tests were made on the basis of the linguistic aspects and used till now, they underestimate the disability of high frequency hearing loss (HFHL). To ameliorate this problem, we analysed the words which were difficult to discriminate in FHL in a commonly used speech testing material using the acoustic analysis method. Also, the words were assorted to establish a basic data for a new speech material which could estimate the disability of HFHL.
METHODS
20 HFHL subjects (age 20-70), selected on the basis of pure tone audiometry, were found to be the descending type. They were tested to repeat the monosyllabic words at 10-15dB HL above the puretone threshold of 1000Hz and checked with the error responses. These words were sorted out according to the error response or the confusion rate and analyzed by consonants and vowels. The words were recorded with an audiologist's voice using a GSI 10 audiometer connected to the personal computer. This was analyzed by the acoustic analysis program that has the MATLAB function. With this program, a word was analyzed by an initial consonant, a vowel, and a final consonant for the intensity, the formant peak frequency and the time course.
RESULTS
The words which were difficult to discriminate for HFHL were sorted out by the confusion rates. The words of articulation score 15-50% were revealed to have low intensity with short duration, and the peak frequency spectrum above 3 kHz. Also the consonant-vowel transition frequency was located above 3 kHz.
CONCLUSION
These results could be used as a basic clinical data to make a new speech discrimination material which evaluates the disability of HFHL more accurately.