Recreational noise exposure and its effects on the hearing of adolescents. Part I: an interdisciplinary long-term study.

This interdisciplinary long-term study examined the effects of recreational noise exposure on the hearing of adolescents. Boys and girls (aged 14-17 years) were examined during a four-year period. Audiological, psychosocial, and sound measurements were performed yearly to determine the hearing threshold level (HTL) of participants in the 250-16000 Hz range, their participation in recreational activities, and the sound levels at discos and through personal music player use. A tendency of the mean HTL to increase in both genders during the study was observed, especially at 14000 Hz and 16000 Hz. Boys had a higher mean HTL than girls. The participation in musical activities increased yearly, 'attendance at discos' being the favourite musical activity for both groups. In general, boys were more exposed to high sound levels than girls. The equivalent sound levels in discos ranged between 104.3 and 112.4 dBA, and between 75 and 105 dBA from personal music players.

Recreational noise exposure and its effects on the hearing of adolescents. Part II: development of hearing disorders.

Part II, continuation of a previous paper, describes the significant hearing threshold shift found during the third year of the long-term study, which continued to be present in the fourth year, in a number of adolescents classified as Subgroup 2, who showed a higher mean HTL in the middle and especially in the high frequency ranges than the rest of the studied adolescents, classified as Subgroup 1. In both subgroups, the subjects showed high participation in recreational activities; nevertheless, the adolescents in Subgroup 2 showed higher participation in some of them in the last year of the study. From the beginning of the study, the mean HTL of the adolescents in Subgroup 2 was higher than the mean HTL of the adolescents in Subgroup 1. The exposure to high sound levels during leisure activities can be a cause of permanent hearing damage among young people with 'tender ears'.