The risk of noise-induced hearing loss depends on total exposure, that is the combination of noise level and noise duration. In addition, more intense and longer duration sounds can cause more hearing loss. However, some very intense sounds, such as a gunshot, or a firecracker, may cause permanent damage with a single brief exposure. Virtually all the structures of the ear can be damaged by loud noise, especially the spiral-shaped sensory organ in the inner ear, which can be torn apart by a sudden intense sound. The panel noted that significant hearing damage can occur without pain or awareness and that currently available hearing aids are unable to restore normal hearing.
Noise damage can occur at any age, including infancy.
There is a broad range of individual differences among people in the amount of hearing loss each suffers as a result of identical exposures. Between the ages of 10 and 20, however, men begin to exhibit poorer hearing than women, a phenomenon that continues well into advanced age. The panel said this observation is attributable to the likelihood that men have had greater exposure to noise. The panel also called for a broadening and vigorous enforcement of existing noise control regulations in the workplace and of product noise labeling information for consumers. One of the panel's recommended top priorities for the 1990's is prevention, including public education regarding the hazards of noise exposure.