Near-Nerve Needle Technique Versus Surface Electrode Recordings in Electrodiagnosis of Diabetic Polyneuropathy

PURPOSE The sural nerve can be examined by either surface electrode recording or near-nerve technique (NNT) for electrodiagnosis of polyneuropathy. This study compared the sensitivity of these two methods and correlated nerve conduction studies to "The Utah Early Neuropathy Scale" (UENS) and HbA1c levels. METHODS In 29 diabetic patients, 55 sural nerves were examined with both antidromic surface recording and orthodromic NNT. The sensitivities were compared with chi-square statistics. Nerve conduction study parameters were correlated with UENS and HbA1c levels using regression analysis. RESULTS More often absent responses were seen with surface electrodes than NNT (15 vs. 0) (P < 0.001). A higher number of normal nerves were found with surface recording (27) than with NNT (15) (P < 0.001). The decrease in sensory nerve action potential amplitude correlated significantly to total UENS scores and UENS subscores for both surface recordings and NNT. However, decrease in conduction velocity and sensory nerve action potential duration correlated to UENS scores and subscores more often for NNT than for surface recording. Similarly, there was significant correlation between HbA1c levels and sensory nerve action potential amplitude and duration for NNT, but not for surface electrode recordings. CONCLUSIONS Near-nerve technique is recommended for better and more sensitive electrodiagnosis of polyneuropathy, and clinical scoring with UENS is of importance for diabetic neuropathy diagnosis.