Resistance of the peripheral nerve to ischemia in diabetic patients--an electrophysiological study.

We studied the effect of ischemia on the excitability of the sensory fibers of the median nerve in 43 patients with non-insulin-dependent diabetes mellitus (NIDDM) by a double stimulation method. Ischemia caused significantly less reduction of nerve excitability in patients with poor glycemic control and in patients diseased for 5 years or longer than in the normal control group. Hyperexcitability after ischemia was markedly greater than normal among short-term, poorly controlled diabetics, and markedly less pronounced among long-term, poorly controlled diabetics. In many diabetic patients with normal conduction velocity or without sensory disturbance, post-ischemic hyperexcitability was remarkable. A study of nerve excitability may be useful as one means of detecting early-stage disturbance of the diabetic peripheral nerve.