Assessment of basic properties of bone-conducted ultrasound perception presented to distant location

摘要

Bone-conducted ultrasound (BCU) can be perceived even by the severely hearing-impaired and has been applied to a novel hearing-aid. Usually, in bone-conduction, vibrators are pressed onto the mastoid process of the temporal bone, however, BCU can be heard on wider area of the body; i.e, the forehead, the muscle of the neck, the clavicle, and the upper limb. In this study, to assess basic properties of distal-presented BCU hearing, detection thresholds were measured when 30-kHz tone bursts were presented to muscles of the neck and the upper limb in normal hearing subjects. Further, to evaluate the temporal resolution of the distant-presented BCU hearing, temporal modulation transfer functions (TMTFs) were estimated for 30-kHz carrier. The results showed that BCUs presented to the distal part, including the forearm, can be perceived at least in the normal-hearing subjects. Also, the temporal resolution BCU hearing was comparable between the mastoid process of the temporal bone and the upper limb. These results indicate the possibility of development of distal-presented BCU devices.