Refractory period impairment in sural nerves of diabetics.

Polyneuropathy is a frequent complication in diabetics. In a non-selected group of 65 diabetics, 30 patients had clinical signs of neuropathy. These patients had more significant changes in electrophysiological parameters than patients without clinically evident polyneuropathy. Significant reduction of sural nerve conduction velocity was observed in 16 of 30 patients with and in 4 of 35 diabetics without clinical signs of polyneuropathy. Additional information was obtained when paired stimuli were applied and the test response latency was measured. Stimulus intervals of 3 ms gave the highest quota of information about involvement of the sural nerve. Significant prolongation of the test response in paired stimulation at intervals of 3 ms was found in 21 of 30 patients with clinically apparent diabetic polyneuropathy and in 16 of 35 diabetics without clinical signs of polyneuropathy.