Double peak response in normal and diabetic sensory motor polyneuropathy

초록

Purpose: Double peak sensory response (DPSR) had been known to represent distal compound sensory nerve action potential in orthodromic nerve conduction study (NCS). Length dependent pattern involvement in diabetic sensorymotor polyneuropathy (DSP) had been well known. We have studied DPSR in normal and DSP for understanding of its relation to symptoms and signs of DSP, routine NCS, and application for the diagnosis of DSP. Methods: In 60 healthy subjects (age 20-70, mean 53 yrs) conventional NCS and DPSR have been obtained in median nerve. In 50 diabetic patients (age 19-81, mean 48 yrs), duration of diabetes, total symptom score (TSS) and other attributes of diabetes studies were added. Composite score (CS) was used for the comparison of NCS. Results: DPSR latencies were delayed and amplitudes were decreased in 3, 4 cm inter-stimulus distance in diabetic group (P＜0.05). And 2nd peak amplitudes in both 3, 4 cm inter-stimulus distance were all decreased in all diabetic patients compared to healthy subjects (P＜0.05). As TSS increased, DPSR latencies were delayed and amplitudes were decreased. (3 cm latency: r=0.759, P＜0.05, 3 cm amplitude: r=-0.616, P＜0.05, 4 cm latency: r=0.670, P＜0.05, 4 cm amplitude: r=-0.668, P＜0.05). And as CS increased, TSS were also increased (r=0.681, P＜0.05) and DPSR latencies were delayed and amplitudes were decreased. (3 cm latency: r= 0.674, P＜0.05, 3 cm amplitude: r=-0.581, P＜0.05, 4 cm latency: r=0.545, P＜0.05, 4 cm amplitude: r=-0.448). There were no correlation between CS and duration of diabetes mellitus or age. Conclusion: In this study, DPSR latencies were delayed and amplitudes were decreased in diabetic group compared to healthy subjects and they were also related to TSS and CS. Therefore, we suggest that DPSR would be an early diagnostic method for diagnosing DSP which progress in length-dependent pattern.