The present state of hearing-aid use in three schools for the hearing impaired in Britain

The present state of hearing-aid use in three schools for the hearing impaired in Britain was investigated by comparing the hearing threshold measured with a hearing-aid earphone whose output sound pressure level was calibrated in a 2-cm3 coupler to the hearing-aid output with all the controls set to the position at which they were regularly used. The results showed that the amplification level of hearing aids was considerably less that that expected from hearing thresholds. It was only in the group with hearing thresholds less that 80 dB SPL that the hearing-aid outputs exceeded 20-30 dB SPL above their hearing thresholds. In the group with hearing loss more than 100 dB SPL, 40% of the ears were getting no functional amplification even at frequencies below 1000 Hz.