Transient sensorineural hearing loss after overuse of portable headphone cassette radios.

Noise-induced sensorineural hearing loss has been associated with industry for many years. One conservative estimate suggests that 10 million Americans may have industry-related, noise-induced hearing loss. Acoustic trauma from any source, whether associated with work or recreations, is detrimental to hearing. The Occupational Safety and Health Administration has set industrial standards for noise levels, with current standards limiting noise exposure to 95 dBA for 2 hours daily. To date, however, there are no recreational standards. Many portable headphone cassette radios produce peak outputs of more than 100 dBA. Temporary threshold shifts could result from listening levels near the maximum output. Permanent sensorineural loss may result with repeated exposure. A pilot study was conducted in which 16 volunteers listened to headphone sets for 3 hours at their usual maximum level. Six volunteers showed transient shifts of 10 dB, and one volunteer showed a transient shift of approximately 30 dB. These shifts returned to normal within 24 hours. As expected, transient shifts frequently occur with recreational use. Therefore, recreational warnings and standards should be established.