農業従事者およびチェンソー取扱い者の末梢機能に及ぼす加齢の影響 : 第1報 痛覚,振動覚閾値の年齢変化

Vibration hazards caused by using vibrating tools include such disorders as peripheral circulatory disturbances, peripheral nervous disturbances and abnormalities of the bones and joints. It is generally acknowledged that the effect of physiological aging on the nervous system gradually increases with age. In this paper, therefore, to assess the effect of aging on the peripheral nervous function as evaluated by pain and vibratory sense thresholds of fingers, 135 farmers and 130 chain saw operators ranging in age from 30 to 69 years were examined. Moreover, 27 normal persons aged between 21 and 37 years served as the control for comparison. The results obtained were as follows: 1) In the control subjects, there was no age-related change in the pain threshold. However, the vibratory sense threshold at a frequency of 125 Hz or 250 Hz showed a tendency to increase with advancing age. 2) In both farmers and chain saw operators, thresholds in the pain and the vibratory sense at a frequency of 125 Hz or 250 Hz showed a tendency to increase with advancing age. 3) The pain thresholds in chain saw operators seemed to be slightly higher than those in farmers in all age groups, but the differences were not statistically significant. On the other hand, the vibratory sense thresholds at a frequency of 125 Hz or 250 Hz in chain saw operators were significantly higher by 5 dB than those in farmers in all age groups. From these results it is suggested that we have to use age-adjusted standard criteria in evaluating thresholds of the pain and the vibratory sense at a frequency of 125 Hz of 250 Hz.