[Internal ear damage in vibration syndrome caused by local vibration]

Unlike with the vibration syndrome caused by general vibration whose clinical picture may exhibit internal ear impairments in the of hearing losses and vestibular disturbances, similar lesions in the vibration syndrome due to local vibration have not been confirmed explicitly. For better explanation of this issue, analysed were the results of audiometric and electronystagmographic (ENG) tests in a group of 40 otologically healthy++ men, in whom during 1986-1987 the angioneurotic vibration syndrome was diagnosed. The results were analysed considering subjects' age and duration of work in exposure; evaluation involved the increase in hearing thresholds for pure tones (audiometer Peters AP-6) and quantitative and qualitative changes in ENG records (electronystamograph Tonnies D-420 TS), calculating, among others, amplitudes and angular velocity of nystagmus slow phase. In 75% of subjects (30 persons) sensorineural hearing losses of different degree were found, mostly within the 3000-8000 Hz range, demonstrating a directly proportional dependence on the length of employment. Symptoms of vestibular disturbances in ENG records were detected in 57.2% (23) persons with marked predominance of the cases of vibration exposure over 10 years. The authors analyse mechanisms of the development of internal ear impairments in result of local vibration and concomitant noise.