Development of a digital noise exposure system for research on noise induced hearing loss

Abstract

Over thirty million Americans suffer from noise induced hearing loss (NIHL). Previous research demonstrated that different types of noises, even with equal sound energies, could produce different amounts of hearing loss. In this project, a novel digital noise exposure system has been developed for generating various noise signals (e.g. pure-tone, Gaussian, impulsive, and complex noise). The developed system can be used to study NIHL in animal models. The system could produce impulse noise with peak sound pressure level (SPL) up to 160 dB, which effectively mimics the noise generated by a military weapon (e.g., M-16 rifle). The preliminary results of in an animal study showed significant permanent threshold shift (PTS) produced by 90 shocks impulse noise with peak SPL = 155 dB generated by the system. In summary, the digital noise exposure system replicates environmental noise allowing researchers to study impulse noise induced hearing loss in a controlled situation.