A Observational Cross Sectional Study to Evaluate the Sensory Nerve Conduction Parameters of the Distal Sensory Nerves in Patients With Impaired Glucose Tolerance and Diabetes Mellitus

Diabetic Peripheral polyneuropathy (DPP) presents as a slowly progressive primary sensory deficit in length dependent fashion, to result in the classic stocking glove distribution. There is recent evidence to indicate that patients with impaired glucose tolerance ( IGT) on OGTT, the prediabetic stage, have three times the prevalence of distal peripheral polyneuropathy than age matched controls. Patients with IGT, even in their preclinical stages, though they have less severe neuropathy than those with diabetes mellitus, have predominant sensory fiber involvement. To support this, other studies of skin biopsies of IGT patients have shown that microvascular abnormalities and neuropathic changes can occur in the prediabetic stage.

Because DPP is length dependent, it is necessary to evaluate the distal sensory nerves, other than the standard sural and superficial peroneal nerves. To support this theory, recent electrodiagnostic studies in DM patients have shown that albeit normal conduction parameters in the above mentioned two nerves, abnormal parameters can be detected in the more distal sensory nerves, such as the dorsal sural nerve, medial plantar nerves and medial dorsal cutaneous nerve.

Although the importance of evaluating the distal sensory nerves has gained much attention, no study has addressed the issue whether NCS parameters of these distal sensory nerves in IGT patients are significantly different from those of healthy controls with no medical condition, and whether these parameters are different to those with patients with diabetes mellitus, who have no previous history of peripheral polyneuropathy.

With this objective in mind, NCS of the distal sensory nerves of the feet were performed to three groups; normal healthy control group, IGT group and diabetes mellitus group.