[Evaluation of the skin sympathetic function by the decrease of skin temperature at the finger tip immersed into cold water].

The change of the skin temperature at the finger tip immersed into cold water was measured in normal volunteers and in patients with disturbances of various portions of sympathetic nervous system with copper-constant thermocouple. The skin temperature of the normal subjects decreased soon after the immersion, partly due to cooling by the cold water, and partly due to the decrease of the skin blood flow. The skin sympathetic activity recorded from three normal subjects using the technique of microneurography presented an increase during the decreasing phase of the skin temperature. The skin temperature of the patients who received stellate ganglion block did not fall and maintained higher level compared to that of normal subjects. These data indicated that the decreasing phase of the skin temperature of the immersed finger is related to the increase of skin sympathetic activity. Cases of vascular neuropathy (lesion in post-ganglionic fiber), Shy-Drager syndrome and pure autonomic failure (lesion in pre-ganglionic fiber), cervical spondylosis and cervical disc herniation (lesion in descending tract of sympathetic system in spinal cord), and bleeding in pons tegmentum (lesion in descending tract in brain stem) were examined and all of them presented poor decrease of the skin temperature during the immersion. The skin temperature decreased, but incompletely in the patients, who had suffered from thalamic infarct and post-central gyrus infarct, and did not feel any sense on the immersion. These results indicate that the decreasing phase of the skin temperature of the finger immersed into cold water depends more upon the efferent than upon the afferent system, and this test is useful for evaluation of the skin sympathetic function.