Bone-conducted ultrasonic perception: Elucidation of perception mechanisms and development of a novel hearing aid for the profoundly deaf

Several studies have reported that bone-conducted ultrasounds (BCUs) can be perceived even by those with profound sensorineural deafness, who typically hardly sense sounds even with conventional hearing aids. The perception of BCUs by the profoundly deaf has been objectively proven using magnetoencephalography (MEG). Furthermore, both the psychological characteristics and the neurophysiological mechanisms underlying the perception of BCUs have been identified by psychophysical, electrophysiological and physical approaches. In addition, we have developed a BCU hearing aid (BCUHA) for the profoundly deaf. Remarkable results have already been achieved with this device, which enabled 42 % of the profoundly deaf subjects in the trial to perceive some sort of sound and 17% of them to recognize simple words. These results suggest the feasibility of this device, but additional development and improvements are needed.