周波数圧縮変換型補聴器の効果について

The effectiveness of a frequency transposing hearing aid (Transonic) was investigated in three patients with severe sensorineural hearing loss and 21 normal controls. All the patients had residual hearing only in low frequency. Severe middle-high frequency sensorineural hearing loss model was reproduced in the 21 normal controls. Little improvement was seen in the articulation scores of these patients and the 21 controls at the first use of Transonic. However, after two weeks auditory training, significant improvement was seen in some speech sounds. In the three patients, the articulation scores of voiceless consonants, in particular/s/, voiced plosives, voiced fricatives and nasal sounds were improved. In the controls, the articulation scores of vowels and consonants such as /s/, /k/, /t/, /n/ were improved. Improvements in articulation scores by this type of training could be explained as follows : with the use of Transonic, speech cues in the high frequency area were transposed to new recognizable cues in the low frequency region.
Sensorineural hearing loss model in normal controls was not the same as actual sensorineural hearing loss, but it was possible to experimentally induce comparable deafness in many individuals. As a result, they could serve as good subjects when investigating the effectiveness of hearing aids.