O6 The utility of distal nerve conduction studies and sural near-nerve needle recording in electrodiagnosis of polyneuropathy

Abstract

Objectives To compare the diagnostic utilities of distal surface electrode recording of dorsal sural and medial plantar nerves and near-nerve technique (NNT) and conventional surface recording of sural nerve. Methods Ninety-one patients referred for electrodiagnostic examination of polyneuropathy (PNP) were included. Bilateral nerve conduction studies (NCS) of the sural nerve with NNT and surface recording, and of the distal nerves with surface recording were done in all patients. Results were compared to 37 age-matched healthy subjects. The final clinical diagnosis retrieved from the patients’ medical records as diagnostic reference standard showed PNP in 68 patients (PNP+) and 20 patients did not have PNP (PNP−). Results The sensitivities of the dorsal sural (68%) and medial plantar (70%) nerves were similar to that of NNT recording of the sural nerve (74%), while the sensitivity of surface recording of the sural nerve was lower (55%). High specificities (93–98%) were seen for sural NCS with both NNT and surface recording and for the dorsal sural nerve, while the specificity for medial plantar nerve was low (76%). Discussion In concert with previous reports, distal nerves have higher sensitivity than conventional sural nerve. Additionally, the sensitivity of distal nerves was found to be similar to examination of sural nerve with NNT. Conclusion NCS of the distal nerves, especially the dorsal sural nerve, have a high diagnostic power at an identical level of that of needle recording of the sural nerve. Significance Examination of distal nerves.should be included into routine electrodiagnostic evaluation of patients with suspected PNP.