Modified collision study to isolate and study small fibre neuropathy in patients with Type 2 diabetes

INTRODUCTION: Diabetic distal symmetrical polyneuropathy (DSPN) can be categorized as small fibre, large fibre, and mixed neuropathy. Even though small fibre neuropathy is the most prevalent, unfortunately it is usually not recognized by routine electrophysiologic studies. In this study, we intend to examine the slow velocity small fibres responsible for small fibre DSPN, by isolating them using collision technique principle in patients with diabetes. METHODS: This is an observational case-control study designed to compare nerve conduction values with application of collision technique in 60 patients with T2D and in 60 age and sex matched controls. RESULTS: The collision study in patients with Type 2 Diabetes showed mean Latency of 10.5 ± 1.7 ms and mean Amplitude of 3.4 ± 2.3 mV on the right side and mean Latency of 10.5 ± 1.7 ms and the mean Amplitude of 3.5 ± 2.2 mV on the left side. There was a statistically significant difference (P value < 0.001) in the amplitute and latency of CNAPs of small fibres in median nerve innervated APBs of both arms between those with T2D and controls. DISCUSSION AND CONCLUSION: Collision study helps to examine the slower conducting fibres of the larger nerves. Our study suggests that the Collision Technique can be used to identify early peripheral neuropathy regardless of the diabetes status, thus making it more practically feasible and cost-effective.