Long-term assessment of auditory changes resulting from a single noise exposure associated with non-occupational...

We examined the long-term sequelae in both ears of 42 patients who reported the occurrence of auditory changes resulting from a single exposure to intense sound levels during non-occupational activities. We divided these patients into two groups, based upon noise exposures of either continuous duration or single high-energy impulse. Audiometric data were available for each of these subjects shortly after their noise-exposure events and follow-up examinations took place more than one year after the noise occurrence (range: 1-16 years). The initial median hearing loss for the continuous-type noise exposure group at 3-8 kHz was found to be 9 dB, relative to the age-appropriate norms, in the more affected ears, and hearing function was found to have returned to normal levels at follow-up. The same initial hearing loss was measured for the impulse-type noise group, but a residual hearing loss of 4 dB was measured at follow-up. Furthermore, the majority of the subjects from both groups reported tinnitus and hypersensitivity to sound at follow-up, but with minimal impact on their lives.