An alternative nerve conduction study method to evaluate early diabetic neuropathy: Ratio of different diameter nerve fibers in peroneal nerve

Different nerve fibers may have disparate conduction parameters even though they are in the same peripheral nerve. Hyperglycemia can have differential effects on nerve fibers, depending on diameter. In diabetes, conventional nerve conduction studies have allowed us to classify a peripheral nerve as normal or not. But, there may be differential involvement in disparate nerve fibers of the same peripheral nerve. This study evaluated the effects of hyperglycemia on nerve fibers of peroneal nerve by diameter. Thirty-five diabetic patients with normal nerve conduction studies and thirty-two healthy controls were included to the study. The peroneal nerve was stimulated from two points (upper and below the fibula head) and recorded from the tibialis anterior (TA) and extensor digitorum brevis (EDB) muscles. Then the ratios of conduction velocity parameters recorded in these sides were compared between the diabetic and control groups. The conduction velocity recorded from EDB seemed to be faster in both groups. But there were no significant differences among the ratios between the groups. Our study has demonstrated the conduction parameters of two nerve fibers with different diameters in the peroneal nerve. The ratios of conduction parameters were similar in both groups, suggesting that fibers in the peroneal nerve are similarly affected by hyperglycemia. © 2015, Research Society for Study of Diabetes in India.