Recent studies for the diabetic polyneuropathy have quantified as well as compared the clinical and the electrophysiological findings. Thirty-one diabetic patients were examined with a conventional nerve conduction study, a late response, a somatosensory evoked potential (SEP), a sympathetic skin response (SSR), a R-R interval, and a needle electromyography (EMG) after the clinical examination. The purposes of this study were to evaluate the correlation of clinical features and electrophysiological findings and to provide reliable criteria for the diagnosis of diabetic polyneuropathy. Diabetic polyneuropathy was diagnosed when a nerve conduction study revealed abnormal findings in two or more peripheral nerves. The following parameters were highly correlated with a diabetic polyneuropathy; ankle jerks (Spearman's r=0.92), H reflexes (Spearman's r=0.92), F waves by the tibial nerve stimulation (Spearman's r=0.88), F waves by the peroneal nerve stimulations (Spearman's r=0.84), and amplitudes of a sensory nerve action potential (SNAP) in the sural nerve (Spearman's r=0.79), SEPs by the tibial nerve stimulation (Spearman's r=0.79). Motor nerve conduction of the upper limbs, R-R interval ratios, and blood pressure changes had no significant correlations with a diabetic polyneuropathy.

We concluded that these clinical and electrophysiological findings with significantly high correlation values would be good parameters for the diagnosis of diabetic polyneuropathy.