![]() ![]() ![]() ![]() 6 Education through hearing loss prevention programs demonstrates some positive impact with improved use of HPDs, although overall has been disappointing in the prevention of hearing loss. NIHL prevention techniques include education, workplace interventions, legislation, personal hearing protection devices (HPDs), and pharmacologic agents. Therapy for NIHL consists of prevention and treatment. The difference between recommended exposure limits and permissible noise exposure limits. The table below shows the difference between the REL and PEL. Since the intensity of sound doubles with each increment of 3 dB, this exposes the individual to roughly the same noise dose based on the physics of sound and the logarithmic decibel scale, 3dB increase is nearly equivalent in the doubling of the sound pressure. Therefore, an 88 dBA sound is permitted for four hours, a 91 dBA sound for two hours, etc. 5 For each 3 dB increase in the average sound intensity from there, the recommended duration of sound exposure is halved. At this sound level over a lifetime of work, NIOSH estimates at least mild hearing loss in 14% of the population. The NIOSH REL starts at 85 dBA over an eight-hour period averaged over time. This means under OSHA, a worker should only be exposed to 95 dbA sound for four hours, 100 dBA for two hours, etc. For every 5 dB increase in the average sound level, the permitted sound is reduced by half. The OSHA PEL recommendations start at 90 dBA for an eight-hour time period. The exposure limits are based on A-weighted frequency response (dBA)-an average of sound intensity giving greatest weight to frequencies essential for speech. The two sets of limits are slightly different at the level, steps, and duration of exposure, but both standards are based on limiting the “dose” of noise individuals are exposed to in a given workday. The National Institute for Occupational Safety and Health (NIOSH), the group responsible for studying NIHL, recommends slightly higher standards for their recommended exposure limits (REL). The Occupational Safety and Health Administration (OSHA) has established permissible noise exposure limits (PEL) for occupational noise exposure, which are enforceable by law. 4 Recommended and Enforceable Noise Exposure Limits 1 In economic terms, NIHL affects about 13% of the working population, with an estimated annual cost of $123 billion a year in the U.S. The prevalence of NIHL is higher with advanced age, the male gender, white (non-Hispanic) and Hispanic ethnicities, education level less than high school diploma, Mexico as country of birth, service in armed forces, smoking history, diabetes, and occupational and those with any kind of noise exposure. 3 It is determined by the severity and duration of the noise exposure as well as the underlying genetics of the individual. 2 NIHL has traditionally been defined as occurring at 3, 4, or 6 kHz. 1 NIHL is the most significant preventable cause of hearing loss in the United States. Erbele, MD, Hearing Committee membersĪpproximately 23 million Americans aged 20 and older suffer from noise-induced hearing loss (NIHL). ![]()
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