Validity of various function tests performed in Japan as a screening test for vibration syndrome.

In Japan, various function tests on the upper extremities are widely performed for the early diagnosis of vibration syndrome. The validity of these function tests was investigated by discriminant function analysis. The correct classification rate of the 120 workers exposed to vibration and the 40 control workers was 83.1%, when including the exposure-to-cold test. Therefore, the function tests were confirmed to be of diagnostic significance as a screening test for vibration syndrome. However, the rate is not sufficient to make a diagnosis only with the function tests. When not including the exposure-to-cold test, the rate was reduced by 10% because insidious functional disorders were missed in the early stage. For the early diagnosis of vibration syndrome, the exposure-to-cold test should be included in the function tests. Furthermore, to enhance the validity of the diagnosis, the results of the function tests should be evaluated together with subjective symptoms and the findings on bones and joints, the central nervous system and the endocrine system.