[Audiometric findings of senior high school students belonging to a Kendo Club].

Between 1992 and 2010, we studied audiometric findings obtained from the annual hearing examination for senior high-school students who belonged to an active Kendo team. The subjects comprised 140 males and 88 females with ages between 15 and 18 years. The pure tone audiometry showed that 69 ears of 45 students (19.7%) had sensorineural hearing loss with the highest threshold shift at 2000 Hz, followed by 4000 Hz. Frequent audiometric patterns included a 2000 Hz-dip, a 4000 Hz-dip and a combined loss of 2000 and 4000 Hz. Some of these affected subjects had shown a completely normal audiogram at the previous examination. Moreover, small-dips with a depth less than 25 dB were found to be limited either at 2000 Hz or at 4000 Hz, suggesting early audiometric changes from a temporary or a permanent threshold shift caused by noise and/or head blows during Kendo practice. The incidence of such abnormal audiograms among this Kendo club members appears to be decreasing year by year owing to the annual check-ups over the 18-year study period, and student counseling regarding the possible adverse effect of Kendo on the inner ear function.