チエンソ-による振動障害--神経耳科的所見
スポンサーリンク
概要
- 論文の詳細を見る
Hearing tests and vestibular and equilibrium function tests were performed in a series of 49 wood-cutters at the regional forestry offices in Kochi Prefecture who had an apparent “vibration illness” due to the long term use of a chain saw, within the framework of workers' Accident Compensation Law. Presenting symptoms in this series were hearing loss in 22 cases, tinnitus in 28 cases, and vertigo in 26 cases. Hearing tests revealed bilateral sensori-neural hearing loss in 36 cases, unilateral sensorineural hearing loss in 2 cases, C5 dip in 3 cases, presbycusis in 5 cases, and normal threshold levels in 3 cases. In the majority of cases, hearing was impaired bilaterally in a frequency range of 4000-8000Hz. Positional nystagmus was demonstrated in 15 cases, which comprised 9 cases of direction fixed positional nystagmus, 2 cases of transitional nystagmus and 4 cases of upward vertical nystagmus. A caloric test performed in 39 patients demonstrated C. P. in 21 cases, D. P. in 8 cases, C. P.+D. P. in one case, no reaction evoked in 1 case and no left-to-right difference in response in 8 cases. An optokinetic nystagmus test revealed horizontal after-nystagmus alone in 10 cases, vertical after-nystagmus in 1 case, and poorly elicited nystagmus in 2 cases. On eyetracking test, a stairway-like pattern was observed in only 1 case; 22 patients had an abnormality on extremity equilibrium function test, but in only one of these 22 cases findings on the test led us to suspect a central lesion. In some cases, the results of vestibular and cochlear function tests suggested the presence not merely of inner ear damage but also of disorders of the central nervous system. In many cases of the series, latent changes persisted despite long term therapy.