宮城県の成人難聴

難聴原因別の検討

抄録

Types of hearing impairments were studied from epidemic and audiometric standpoints in 2, 180 adults (1, 356 men and 824 women) with hearing losses above 40 dB in Miyagi Prefecture.
The results were as follows:
1. In general, the occurrence of hearing impairments was the lowest in urban areas, higher in seaside districts and the highest in farming communities. The occurrence of hearing impairments was about 1.6 times greater in men than women.
2. The occurrence of presbycusis increased gradually after 40 years of age and reached its peak among people in their 60's and 70's. Hearing loss increased with advancing age, and the audiometric pattern was generally of the symmetric and gently sloping group.
3. Two types of hereditary hearing loss were observed. One was severe hearing loss which appeared during childhood. Its audiometric pattern showed a residual only in low frequencies. The other was hearing loss which appeared after puberty immediately following an acquired disease. Its audiometric pattern was usually of the flat group.
4. Among men, hearing impairments were very frequently caused by head or acoustic trauma (217o' of all men with hearing losses). The audiometric patterns were usually of the gently sloping group and occassionally of the c5-dip group. In contrast, hearing impairments among women were often related to pregnancy or childbirth (8.4% of all women with hearing losses). Its audiometric pattern was of the flat group.
5. Ototoxic hearing impairment due to the use of streptomycin occurred more often among city dwellers than among residents of farming communities. The audiometric pattern was of the gently sloping and sharp sloping groups.
6. Meniere disease sometimes causes hearing loss and is usually accompanied by tinnitus. Its audiometric pattern was of the gently sloping group, but asymmetric between both ears.