Noise-induced hearing loss and portable radios with headphones.

Portable radio/cassette players with headphones have gained increasing popularity in recent years. Volume settings are often increased to override environmental noise, perhaps placing the listener at risk for noise-induced hearing loss (NIHL). A total of 190 public college students in NYC were studied via a self-administered questionnaire regarding the volume setting used and weekly exposure in hours to these units. Three popular models were tested using a Bruel and Kjaer sound level meter, octave band filter and artificial ear. Sound levels were measured at various frequencies (250-8000 Hz) and an overall measurement obtained using the "A"-weighted scale. Based on OSHA criteria for permissible noise dose (i.e. intensity X duration) in the work place, auditory risk criteria were developed. Of all students who used such radios 31.4% equalled or exceeded the maximum allowable dose permitted by these criteria (41.2% of the males and 29.2% of females). This sex-related difference in risk, while not statistically significant, warrants further investigation. Of the total 'at risk' group 50% exceeded the risk criteria by more than 100%. These results suggest that portable radios with headphones may be capable of causing permanent hearing loss in a large proportion of radio users.