[The skin vasomotor dysfunction of the juvenile muscular atrophy of the distal upper limb--investigation by the ice water immersion test].

We investigated the skin vasomotor function of the juvenile muscular atrophy of the distal upper limb (JMA) by the ice water immersion test. The skin temperature of the bilateral second fingers during ice water immersion were measured in 17 patients with JMA and 25 normal controls. The insufficient fall of the skin temperature during ice water immersion was observed in 5 patients (3 patients in atrophic side, 2 patients in non-atrophic side). The insufficient recovery of the skin temperature was observed in 6 patients (3 patients in atrophic side, 3 patients in non-atrophic side). The both of the insufficient fall and recovery of the skin temperature was observed in one patient (both sides). The insufficient fall of the skin temperature indicates the hypofunction of skin vasomotor activity, and the insufficient recovery of the skin temperature indicates the hyperfunction of skin vasomotor activity because JMA has no disturbance of the peripheral sensory nerve fibers. We conclude that the responsible lesion of these abnormalities may be in the descending sympathetic tract in the cervical spinal cord.