2018 Volume 61 Issue 6 Pages 531-537
In 2017, the indications for adult cochlear implants were revised in Japan, as follows; 1) severe sensorineural hearing loss with a pure tone hearing average (PTA) of over 90dB, and 2) PTA is more than 70dB, but less than 90dB, and maximum speech discrimination score while using hearing aids is lessor than 50%. In this study, we examined the validity of the new indication criteria from the relationship between PTA and the maximum discrimination score of unaided, and the relationship between PTA and the maximum discrimination score in users of hearing aids and cochlear implants.
The subjects were 37 adults with cochlear implants and 77 adults wearing hearing aids
.The results revealed a negative correlation between the PTA and the maximum discrimination score calculated for unaided. The maximum discrimination score at a PTA of 70dBHL was 45%. Comparison between users of hearing aids and those with cochlear implants revealed, that the discrimination score in both groups was 70dBHL of the PTA (50%). At the hearing level of 70dBHL or more, the speech discrimination score decreased further in users of hearing aids, while it increased in users of cochlear implants.
It would seem necessary to verify the indication criteria for cochlear implants from early on in the future, due to the technical advantage of hearing preservation due to progress in medical technology and improvement of hearing performance.
