Bone-conducted (BC) sounds are typically presented to the mastoid or condyle processes. On the other hand, BC-sound presentations to face such as the nasal and zygomatic bones have also recently been investigated. Because the face has complex structures, BC sounds presented to facial parts are likely to show different characteristics from those presented to conventional parts. However, the characteristics of BC sound presented to different part of the face have not yet been studied in detail. To investigate frequency- and temporal resolutions and speech-perception characteristics when BC sounds were presented to facial parts (nasal bone, infraorbital region, zygomatic, jaw angle, and chin) in normal-hearing subjects, we measured difference limens for frequency (DLFs), temporal-modulation transfer functions (TMTFs), and monosyllable articulation in Japanese, respectively. The results showed that frequency- and temporal-resolutions and intelligibilities obtained in facial parts were close to those of conventional parts. It was also indicated that presentation parts and propagation distance to the auditory organs do not affect frequency- and temporal resolutions. These results indicate that practical frequency- and temporal information and speech perception are possible with BC devices attached to different facial parts.
Nakagawa et al. (Wed,) studied this question.