2013 Volume 56 Issue 4 Pages 291-297
We investigated the changes in the prevalence of hearing impairment in primary school children in Sendai City from 1998 to 2008, and obtained the following results:
1) The number of subjects decreased in response to the reduction in the population of 6-to 12 year-old children in Japan, but increased slightly after 2005 in Sendai City.
2) The occurrence rate of hearing impairment decreased from 0.58% in 1998, with little fluctuation. This reduction was considered to be mainly attributable to the decreased occurrence of conductive hearing loss caused by secretory otitis media.
3) The prevalence of sensorineural hearing loss (SNHL) varied from 0.20% to 0.30%.
4) The prevalence of conductive hearing loss decreased gradually from 0.20% in 1998 to 0.04% in 2007.
5) While the prevalence of hearing impairment caused by secretory otitis media decreased each year, secretory otitis media still remains the main cause of conductive hearing loss.
6) The prevalence of functional hearing loss, including suspected cases, increased remarkably in latter years of the study period－this was the most remarkable finding of this study.
7) The incidence of unilateral severe SNHL was 0.04% or less, with no significant changes during the study period.
