In recent days in Japan, Raynaud's phenomenon and some other symptoms such as pain or weakness of upper extremities are getting troublesome problems among chain saw using wood cutters. These conditions are commonly thought due to vibrating tools. Since LORIGA first reported Raynaud's phenomenon due to pneumatic hammer, many of papers have been published. In spite of their efforts, no effective treatment methods have been developed. Ray-naud's phenomenon remains after stopping to use tools, and pain or paresthesia also continues. One of the purposes author looked upon is analysis of clinical symptomatology of self-experienced cases of 87 chain saw men and 30 chipping machine users. Another is to study neuro-circulatory relationship in digital vessels. Clinical Study Raynaud's phenomenon were found in 65.8 per cent of chain saw men and in 86.8 per cent of chipping machine users. In chipping machine users the phenomenon occurred in one hand of handling hammer tip and none in another side of supporting machine. Development of the phenomenon were seen over several years with the most high incidence between 3 to 5 years. Paresthesia were the second prominent symp-tom in chain saw men, which were aggravated by cold weather, and nocturnal paresthesia (MARSHALL) were complained in 5 cases of chain saw men. This phenomenon were suggestive of ischemic neuropathy clinically. Sensory loss were complained in 75.8 per cent of chain saw men and hard hearing were observed almost in half of them. Neurologic examination revealed peripheral neuropathy. Sensory disturbances is the most prevalent with glove and stocking type loss. Tendon reflexes were found hypoactive in many of cases. Elec-tromyographic study showed fibrillation voltage and long duration discharge, suggesting peripheral nerve involvement. Such abnormal discharges in EMG were found with less relationship to duration of tool use or development of Raynaud's phenomenon. Here we could conclude clinically that disorders due to chain saw and chippine machine are peripheral neuropathy and digital circulation disturbance. Brachial arteriogram showed no obstructive lesions and microscopically no histological changes of minor vessels were found. Digital plethysmography of Reflectoric method fluctuated asynchronously and abnormal vascular response were obtained in Valsalva technique or mental arithmetic stimuli.
