Threshold of hearing, vibration, and discomfort in a group of severely hard of hearing and profoundly deaf students

When the e a r i s stimulated by high-intensity lowfrequency sounds by means of ordinary earphones a sound p res su re is reached were tacti le receptors a r e stimulated. Different attempts have been made to establish the audiometric threshold of this tactile sensation. During pure-tone audiometry i t was observed that some severely hard of hearing and profoundly deaf subjects could give three thresholds: hearing, vibration, and discomfort. Measurements were made on 52 ea r s . The obtained tactile threshold ag rees reasonably well with the resu l t s f rom other studies. Comparison between the obtained hearing threshold' and the obtained vibratory threshold shows that detection threshold measurements cannot be used to diagnose total hearing loss . If, however, a detection threshold during puretone audiometry is obtained fo r any frequency above 1500 Hz o r if a threshold for lower frequencies a r e obtained a t lower intensit ies than the established vibratory threshold, this is very Likely a sign of the existence of a residual hearing. 'How useful this residual hearing is for speech per ception and the learning to speak must be established by means of other type of measurements .