Bone Conduction Head Sensitivity Mapping: Bone Vibrator

Report No. ARL-TR-3556
Authors: Maranda McBride (NC A&T State Univ); Tomasz R. Letowski and
Date/Pages: July 2005; 45 pages
Abstract: The military is interested in ways to incorporate radio communication in a multi-tasking environment. Bone conduction (BC) radio communication is an attractive means to communicate because it offers the ability to transmit and receive radio communication without compromising auditory awareness of the environment. Several companies are attempting to accommodate the needs of the military by creating communication devices that incorporate BC technologies. However, the effectiveness of these devices differs in many respects. One factor that affects the detectability of signals received via BC is the location of the BC transmitter (vibrator) on the head of the user. The intent of this study was to identify optimal locations for the placement of a BC vibrator, based on hearing threshold levels of various signals. Eleven signals were transmitted via bone conduction to 11 head locations of 12 volunteers. Results of the study indicate that the condyle (an articular prominence of a bone) is the most receptive location for a BC transducer because it generates the lowest overall threshold levels. Other sensitive and thus recommended locations include vertex, mastoid, and temple. The jaw angle location also resulted in relatively low threshold levels; however, it is difficult to maintain a stable position of the vibrator at this location, and therefore, this position is not recommended.
Distribution: Approved for public release
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Last Update / Reviewed: July 1, 2005