[Studies on the vibration disease - an attempt of a new classification (author's transl)]

In the first section of this study, a survey was made of 1,215 subjects who had been using mowing madchines. Of them 548 subjects without clinical symptomes were examined closely. Vibration threshold and maximal grasping power showed a normal distribution. Since the values decreased with an advancing age, limit values for each age range were calculated from respective probability vales. Advancing age did not affect skin temperature which showed a skewed distribution: limit values therefore were obtained from cumulative frequency distribution. In the second section, we investigated the actual conditions of the authorized patients with vibration diseases. Few severe cases were encountered, but adequacy of the conventional classification as to the degree of severity was questioned. Finally, an attempt was made to classify the disorder according to our new criteria of RNA system. The new system revealed that the vibration disease is classifiable into 7 types: R, N, A, RN, RA, NA and RNA. Single form such as R and N type appeared relatively earlier in life with shorter duration of exposure to vibrating machines. A few cases of A type were seen. Combination form such as RN, RA, NA and RNA type was the form of more severly deranged disorder, as judged from the age of onset, duration of exposure to vibrating machines, physical signs and also laboratory findings.Therefore, the new classification with RNA system appears more adequate in describing the pathosymptomatology of the vibration disease than the conventional method hitherto used.