Discriminant Analysis of Raynaud's Phenomenon Caused by Chain-Saw Operation in Private Forest

The medical examinations of chain-saw operators were carried out in accordance with the notification of the Labor Ministry. The total subjects of the chain-saw operators examined were 255, from whom the control group, consisting of 66 subjects who did not complain of symptoms caused by Raynaud's phenomenon and at the same time had nothing abnormal in the medical examinations, was selected out and compared with the patients group, consisting of 119 subjects who complained of the same symptoms and also had something abnormal in the examinations. All the parameters obtained were changed for normal distribution. In the comparison between the above two groups, all the indices indicated the statistical significance. False negative rate, however, showed the range from 21.8% (vibratory sense threshold at 5 min. after cold immersion) to 59.1% (value of nail press test before immersion). Since the false negative rate obtained from the above data showed an unexpected value, the diagnosis of vibration disease based on the tentative criteria of each index may lead to erroneous results. Therefore, this discriminant analysis aimed at an objective diagnosis by using the eighteen indices including the function of peripheral circulation, peripheral nerve and age. The results can be summarized as follows. 1. The theoretical error was 8.9%. 2. Only one subject of the control group was recognized as having the symptoms of white finger. 3. In 119 subjects belonging to the white finger group, fourteen were recognized as not having white finger. Among those fourteen : a) There were six subjects who used to have the symptoms of white finger but none at present. b) There were five subjects who suffered from white finger symptoms at times, but whose symptoms seemed to have been caused by the injuries received before. c) Unknown origin (3 subjects) 4. The index of vibratory sense threshold (5 min. after immersion) had an effective in fluence on the separation between the patients and control group.