Nerve conduction abnormalities in different stages of glucose intolerance

Aims: To look for changes in nerve conduction velocity (NCV) in early stages of glucose intolerance, i.e. in impaired glucose tolerance (IGT) and in asymptomatic newly diagnosed Type 2 diabetic subjects (NDD). Materials and Methods: A total of 225 subjects were categorized as: Group 1: Subjects with normal glucose tolerance (NGT), Group 2: IGT subjects and Group 3: NDD subjects. Motor (MCV) and Sensory nerve Conduction Velocity (SCV) measurements were done. Results: The mean MCV was significantly lower in the NDD group (47 ± 5 m/s) when compared with the other two groups (IGT=50 ±4.5 m/s; NGT= 53 ± 4 m/s; P=0.0001). The IGT group of subjects also exhibited a significantly lower mean MCV when compared with the NGT subjects (P=0.0001). The mean SCV in the NDD group (42+10 m/s) was also significantly lower (P<0.0007) than the NGT (46+6 m/s) and the IGT (48+10 m/s) groups. No significant difference in the mean SCV between the NGT and IGT groups was noted. In the multiple linear regression analysis both age and male gender were the risk factors for abnormal MCV and SCV. Abnormal MCV was found to be associated with 2-hr post glucose levels (R 2 = 14.5%), while HbA1c (R 2 = 4.9%) contributed towards abnormal SCV. Conclusion: Abnormal NCV is a common finding in NDD subjects. Slower mean MCV demonstrated by IGT subjects, calls for early screening of these subjects for complications. when compared with non-diabetic subjects, due to diabetic neuropathy. 2 The presence of other vascular complications such as peripheral vascular disease in diabetes increases the risk of diabetic foot complications. 3 However, the progression of neuropathy can be reduced by early detection and intervention. 4 Nerve conduction studies, primarily nerve conduction velocities are considered one of the most sensitive indices of the severity of neuropathy. 5 Nerve conduction tests are used to localize lesions and to describe the type and severity of the pathophysiologic process, including alterations in function that are not recognized clinically. In Type 2 diabetic patients decreased Nerve Conduction Velocity (NCV) is probably one of the earliest neuropathic abnormalities and is often present even at diagnosis. Thereafter, slowing of NCV generally progresses at a steady rate of approximately 1 m/s/year and it shows a correlation with the duration of diabetes. 6