めまい・平衡障害をともなう騒音性難聴の6症例

抄録

Six male patients complained of vertigo or disequilibrium accompanied with occupational hearing loss.
Two of them worked in very noisy places for three years in the past and theothers have been working for 15 years or more. Their audiogram showed bilateral C⁵dip or high tone hearing loss. All of them were suffering from unilateral or bilateral tinnitus. Three of them (group A) have often felt static and gait imbalances while the others (group B) have experienced repeated rotatory vertiginous attacks. All cases of group Bshowed positional or positioning vertigo, rotatory nystagmus and decreases of caloric response. Onthe contrary, all cases of group A did not show any nystagmus or abnormal caloricresponse. The authors speculated that the patients of group A have received excessive stress by noisy circumstance in long terms, and this stress could cause insufficiency of cardiovascular system, vertebrobasilar arteries and autonomic nerve system. In the patients of group B, their inner ears were damaged not only in the cochlear but also in the vestibularsystems because of exposure to high intensity noise for a long period of time.