A digital hearing aid having a function of intonation emphasis

The digital hearing aid we designed can slow down speech without any pitch frequency change by using a digital signal processor. We have proved that the device is effective for the elderly sensorineural hearing impaired, especially when sentences are spoken rapidly. It also slows down pitch frequency changes, causing the intonation of the speech to become less pronounced. In this paper, we investigated the auditory characteristics of the hearing impaired regarding intonation distinction in order to improve our digital hearing aid. From the results of the auditory tests, it was found that most of the sensorineural hearing impaired could not distinguish the intonation of the word /ame/ which has different meanings depending on its intonation. It was also found that intonation emphasis processed by the digital hearing aid was very effective for distinguishing spoken words which have similar intonations.