Diagnosis of diabetic polyneuropathy. Correlation between clinical and instrumental findings and assessment of simple diagnostic criteria.

In the present study minimal clinical and electrophysiological criteria for the diagnosis of diabetic polyneuropathy (DP) have been tested in 48 unselected subjects attending an outpatient service for diabetics at the University Hospital of Chieti. A standard electrophysiological examination was performed in all patients on the median nerve (sensory and motor), peroneal nerve and sural nerve. Depending on the importance of the laboratory values for each nerve, nerve conduction velocity, distal latency and potential amplitude were given separate scores ranging from 0.5 to 2. A diagnosis of probable DP was made when abnormal findings were present in more than one nerve with a total score of 2.5 or more. As a whole, 28 cases (58%) had abnormal laboratory findings supporting the diagnosis of probable DP. There was a relatively high correlation between probable DP and a positive clinical examination although the validity coefficients of the neurological exam were not high enough to allow its use as a screening test for DP.