Ischemia and sensory nerve conduction in diabetes mellitus.

Sensory conduction along the median nerve was evaluated during 30 minutes of ischemia in patients with diabetes mellitus. There was abnormal persistence of the sensory evoked potential in 19 of 22 diabetic patients, but not in normal controls, patients with nonmetabolic neuropathies, or 5 of 6 patients with motor neuron diseases. There was an excellent correlation between ischemic resistance and effective control of glucose metabolism, as manifested by Hb A1C levels. These data suggest that abnormal ischemic resistance in diabetes may be the most sensitive indicator of peripheral neural dysfunction even when there are no other electrophysiologic or clinical abnormalities.