Association of Sensory Nerve Action Potential Amplitude and Velocity With Type 2 Diabetic Peripheral Neuropathy

Background: There is ongoing controversy regarding the predominant type of nerve injury in diabetic peripheral neuropathy, whether it is demyelination or axonal degeneration. Objective: This study aimed to investigate the association between nerve conduction study parameters, specifically nerve conduction velocity and the amplitude of the action potential, with diabetic peripheral neuropathy and determine their potential as early indicators of the condition. Methods: A cross-sectional study was conducted involving diagnosed type 2 diabetes mellitus patients, who were divided into two groups: Group I (n = 111) with symptomatic diabetic peripheral neuropathy and Group II (n = 109) without clinically detectable peripheral neuropathy. Age and sex-matched healthy controls (n = 100) were also included. Nerve conduction velocity measurements were performed on both upper and lower limbs, with motor nerve conduction study focusing on the dominant side using the median and posterior tibial nerves and sensory nerve conduction study using the median and sural nerves. Results: The nerve conduction studies revealed significantly lower sensory nerve action potential amplitudes and compound muscle action potential amplitudes in the median, posterior tibial, and sural nerves of the diabetic groups compared to the control subjects. Furthermore, these changes were more prominent in patients with peripheral neuropathy. Among the 220 diabetic patients analyzed, 135 (61.36%) exhibited nerve conduction abnormalities. The highest rate of abnormality was observed in the sural nerve, followed by the posterior tibial and median nerves. The most common abnormality detected in diabetic patients was a decrease in sensory nerve action potential, followed by a decrease in sensory nerve conduction velocity. Conclusion: The study findings suggest an association between reduced sensory nerve action potential amplitude and diabetic peripheral neuropathy. These results highlight the potential of sensory nerve action potential and velocity as a sensitive indicator of peripheral neuropathy in diabetic patients.