Hearing in an ambulance paramedic population.

Ambulance cab noise levels during siren use, hearing levels of 56 ambulance paramedics, and hearing acuity changes of four ambulance paramedics during a 14-year period were examined to determine whether environmental noise levels are sufficient to produce hearing loss, to determine if hearing loss is indeed present in ambulance paramedics, and to determine if ambulance paramedics lose heaing acuity at rates faster than "normal" peers. Ambulance cab noise levels during siren use were intense (mean of 102.5 dBA in a common conditions), well above the Occupational Safety and Health Administration's suggested guidelines of 90 dBA. Hearing levels of paramedics were reduced from presbycusis expectations. In the lower and higher frequency ranges, the personnel showed hearing acuity approximately one standard deviation below the normal mean. This meant that mean hearing thresholds were depressed approximately 5 dB to 2 dB, depending on age and frequency. Ambulance paramedics over a 14-year term appeared to lose hearing acuity at a rate faster than "normal" peers. Implications from this study for hearing conservation are explored.