The Present State of Hearing Aid Use in Three Schools for the Deaf in Japan

Abstract

The present state of hearing aid use in three schools for the deaf in Japan was investigated. The hearing threshold measured with a hearing aid earphone, whose output sound pressure level was calibrated in a 2cm³ coupler, was compared with the hearing aid output for the 70dB input. With all the controls set to the position regularly used.
The results showed that the amplification level of hearing aids was considerably less than that expected from hearing thresholds. In the group with hearing thresholds above 100dB SPL, the aided levels were below hearing thresholds in 60 percent of the ears at 1000Hz, 84 percent at 2000Hz, and in all the ears except one in 99 at 4000Hz. In the group with hearing thresholds below 100dB SPL, most of the aided levels were a little less than 10dB above the hearing thresholds except at 4000Hz.
It was pointed out that the re-setting of volume controls of the hearing aids and the search for greater amplification at 4000Hz were urgently needed for better use of residual hearing in these children.