CPT Leanne M. Cleveland and David A. Eddins, Ph.D
Noise induced hearing loss is the most preventable type of hearing loss. In spite of this fact, several million dollars are distributed every year to veterans of the US Armed Forces as compensation for hearing loss sustained as a result of military service. Recent numbers indicate that noise induced hearing loss has increased exponentially for our active duty soldiers involved in GWOT and OIF. Soldiers are reluctant to use hearing protective devices because they think that earplugs will impair their communication and word recognition abilities, thus reducing their awareness and safety in a combat environment. The Combat Arms earplug is a passive, non-linear earplug available for issue to soldiers of the US Army which addresses these awareness issues. The Combat Arms earplug uses a perforated acoustic filter. The resistance properties of the filter increase non-linearly as the velocity of air particles increase. This allows acoustic sound pressure to enter the ear canal unimpeded up until a level of 110 dB peak pressure. Thus the high frequency peak pressure levels associated with impulse noise are attenuated, and the cochlea is protected from acoustic trauma.