Hearing Conservation in the U.S. Army

Abstract

CONTINUED exposure to high-intensity noise can result in hearing loss, thus affecting the health, efficiency, and well-being of persons exposed. This loss may be temporary, disappearing after a period of nonexposure, or it may be permanent, creating an irreversible impairment of a person's ability to hear certain sounds. This impairment is caused by injury within the cochlea and initially affects the hearing of sounds with frequencies between 4,000 and 6,000 hertz. Extensive damage to the ability to perceive high-frequency sounds may be sustained before loss of hearing in the important range of speech (500-2,000 hertz). Continued exposure may cause a progressive hearing loss in the speech frequencies, severely handicapping the victim. The need for a comprehensive hearing conservation program depends on the potential noise hazard. Many yardsticks are available to preventive medicine and safety personnel for making this determination. The best subjective indication comes from the person who complains that conditions are annoying or unsatisfactory. These conditions take many forms, but the most prevalent include difficulty in communicating by speech while in a noisy area, a ringing sensation in the ears (tinnitus), reduced auditory sensitivity (temporary threshold shift), and general fatigue and irritability. This type of inherent warning system sometimes fails when people have developed, througl years of being exposed to a noisy environment, acceptance of these conditions. These persons, singly and as a group, fail to recognize, through design or ignorance, the deleterious effects that high-intensity noise may have on their hearing. Such persons include career infantry and artillery soldiers, some older aircraft pilots, and certain workers such as carpenters, machinists, and boilerroom operators. It is their situations which require maximum emphasis on health education, supervision, and discipline of personnel.