Noise

Noise can affect hearing in the occupational setting but can have other effects where exposures are non-occupational. For clinical purposes, noise is measured in decibels weighted according to the sensitivity of the human ear (dB(A)). Regardless of source, the effects of overexposure to noise are similar. Initially there is a temporary threshold shift, where reversibility of hearing loss is possible with removal away from further noise. Noise-induced hearing loss occurs following prolonged or intense exposure, with poor prospects for improvement of hearing. The classical audiogram for noise-induced hearing loss shows a 4 kHz dip. Non-auditory effects of prolonged noise exposure include annoyance, sleep disturbance, hypertension, and cardiovascular disease, stress, and impaired cognitive performance. Prevention of noise-induced hearing loss is by reducing exposure to noise at source minimizing exposure time, using hearing protection, and participating in surveillance.