Assessment of Nerve Conduction Abnormalities in Upper Limb of Type 2 Diabetes Mellitus and Their Correlation with Disease Duration and Glycemic Profile

Background

Diabetes mellitus (DM) comprises a group of metabolic disorders that share the common feature of hyperglycemia.

Type 2 DM is a heterogeneous group of disorders characterized by variable degrees of insulin resistance, impaired

insulin secretion, and excessive hepatic glucose production. Diabetic neuropathy is a common microvascular

complication of Type 2 Diabetes Mellitus (T2DM) and is often subclinical in its early stages. While lower-limb

involvement has been extensively studied, data on upper-limb nerve conduction abnormalities and their association

with glycaemic profile remain limited.

Materials and Methods

This cross-sectional observational study included 60 patients with T2DM aged 30–60 years of both genders and was

conducted at our institute after obtaining institutional ethical clearance. Motor and sensory nerve conduction studies

of the median and ulnar nerves were performed using standard techniques. Fasting blood sugar, postprandial blood

sugar, and glycated haemoglobin levels were measured. Association between nerve conduction parameters and

disease duration were assessed using Pearson's correlation coefficient.

Results

The study population had a mean age of 47.87 ± 7.16 years and mean diabetes duration of 8.53 ± 3.70 years, with

predominantly poor glycaemic control (8.01 ± 0.62). Median nerve sensory conduction velocity was markedly

reduced compared to motor conduction, indicating predominant sensory involvement. Median sensory conduction

velocity showed a highly significant negative correlation with disease duration (r = −0.377, p = 0.003), while

median motor latency and conduction velocity also deteriorated with increasing duration. Ulnar nerve parameters

were relatively preserved, showing only minimal changes. No consistent association was observed between HbA1c

and most nerve conduction parameters.

Conclusion

Upper-limb nerve conduction abnormalities are common in T2DM, even in the absence of overt neuropathic

symptoms, with predominant sensory demyelination and preferential involvement of the median nerve. Disease

duration is a stronger determinant of nerve conduction deterioration than glycaemic profile. Upper-limb nerve

conduction studies may serve as a valuable tool for early detection of diabetic neuropathy and emphasize the

importance of long-term metabolic control.