有機水銀中毒症における聴力，前庭平衡機能障害について

VESTIBULAR AND HEARING DISTURBANCES IN ORGANIC MERCURY POISONING

　Ⅰ．まえがき

　いまから10数年前に熊本県に発生した水俣病は世人の注目を浴び，ジャーナリズムを賑わしたが，最近新潟市の北部阿賀野川下流地域に再び熊本県の水俣病と類似の症状を呈する患者が集団発生し再び世間の注目を集めたことは周知の通りである。

　しかし水俣病が工場廃水中の有機水銀剤による災害そのものであるとの最終的結論に達したのはつい最近のことで，新潟の水俣病（いわゆる阿賀野病）にいたつては，その原因が果して工場廃水であるか否かについてなおはげしい論争がつづいている現状である。

　The author investigates the aural disturbances, vestibular and hearing, that had occurred in 25 cases of organic mercury poisoning. And the results are follows:

　A few cases showed spontaneous and positional nystagmus, many of them showing pathological findings such as optokinetic nystagmus which made one suspect of central disorders that may be manifested by bilateral dimunition,interruption, increase in the secondary phase of the nystagmus, and dissociation of between optokinetic and vestibular DP. The latter was found in 10 cases but no case showed CP in caloric tests.

　On the basis of available evidence, the organic mercury poisoning is considerend as a disease effecting the central nervous system. Vestibular disturbances in these cases may exist without any signs of vertigo yet, cerebral ataxia and dysequilibrium are prevalent in many cases.

　Most cases affected with dysequilibrium showed the features of retrocohlear deafness. With vestibular examinations the author concludes, disturbances caused by organic mercury poisoning in the region of the 8th nerve are probably the result of its central action rather than peripheral.