Abstract
This study describes measurements and detection tests given to hearing-impaired people with a single vibrator, VIBAR-SUVAG Type 74 R50, which is used with SUVAG apparatus according to the Verbo-tonal Methodology of rehabilitation.
Both physical and perceptive measurements were taken. The frequency-response curve of the vibrator had a small peak around 300Hz and remained flat at a high frequency range. Comparing the amplitude of the speech sound with the one of the vibration from the same sound, very little difference was observed. Therefore, the vibrator keeps its acoustic features when transfering from speech sounds. With the vibrator in the palm of the hand, high frequency tones above about 3000Hz can not be perceived. On the contrary, low frequency tones below about 500Hz can be sensitively perceived. Prosody; i. e. rhythm, in tonation, duration, intensity, etc.; which consists of low frequency elements, is mainly perceived through the vibrator.
Eight trained hearing-impaired people, ages 7-20 years, each with a mean hearing loss above a threshold of 75 dBHL, were tested using only the vibrator without any hearing aids. They correctly detected 48% of ten everyday greeting words and 86% of six sentences including long vowels (“choon”) and/or double consonants (“sokuon”), which are phonological characteristics of Japanese.
These results were obviously high scores. The vibrator and prosodic information are both considered to play an important role in perceiving speech sounds. The vibrator seems to be especially suited for training for long vowel and double consonant sounds which hearing-impaired children can not reproduce clearly.
