Evaluation of Extended-wear Hearing Aid Technology for Operational Military Use

The primary goal of this research effort is to determine the potential viability of the Lyric device both as a deployable hearing aid for Service Members with existing hearing loss and, in the future, as a possible form factor for a transparent hearing protection device that could protect the hearing of normal-hearing listeners without degrading auditory situational awareness. To this point, significant progress has been made in this evaluation process. The devices have been tested electro-acoustically for impulse noise protection, both with C4 and with a blast tube, and they have been found to provide impulse noise protection comparable to commonly-used passive protection earplug devices. Electroacoustic tests in continuous noise, as well as preliminary behavioral tests, suggest that continuous noise protection is also comparable to conventional earplug devices. Preliminary behavioral testing suggests that, in the active mode, the devices allow external sounds to pass through at frequencies up to 12 kHz, which provides excellent preservation of situational awareness and localization accuracy comparable to the open ear. An individual who has worn the devices in two combat deployments was identified, and his testimonial appears to provide support for the suitability of the devices for use in military environments. Full-scale testing of normal hearing subjects is nearing completion at WPAFB and afield-test for active duty hearing aid users is underway at the Walter Reed National Military Medical Center.