Ulnar neuropathy at the elbow: Reappraisal of the wrist-upper arm latency difference between ulnar and median nerves. Issue 2 (February 2020)

• Record Type: Journal Article
• Authors: Di Virgilio, G.; Grapperon, A.M.; Fayerstein, J.; Goudot, M.; Nollet, S.; Ochsner, F.; Théaudin, M.; Truffert, A.; Tsouni, P.; Vial, C.; Wang, F.C.; Pasquier, J.; Tatu, L.; Attarian, S.; Kuntzer, T.
• Is Part Of: Clinical neurophysiology. Volume 131:Issue 2(2020:Feb.)
• Page Start: 372
• Page End: 376
• Publication Date: 2020-02
• Subjects: Amp peak peak amplitude -- CNAP compound nerve action potential -- CTRL healthy control -- DLat difference in latency -- GNP generalized neuropathy -- Lat peak peak latency -- NCS Nerve conduction studies -- UNE ulnar neuropathy at the elbow; Ulnar neuropathy -- Nerve conduction study -- Neurophysiology; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2019.11.022
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: Ulnar neuropathy at the elbow can be diagnosed by comparing ulnar to median nerve motor latency. Ulnar-median latency difference >0.69 ms indicates ulnar neuropathy. Sensitivity and specificity of this approach is similar to standard nerve conduction studies. Abstract: Objectives: To evaluate the sensitivity and specificity of the latency difference (DLat) between ulnar and median nerves of the arm after stimulation at the wrist; one of the easiest techniques proposed for recognizing ulnar neuropathy at the elbow (UNE). As latency difference is not a standardized technique, we set up a multicenter study to recruit large numbers of normal subjects and patients with UNE or generalized neuropathy. Methods: Six centers participated in the study with data obtained from three groups of participants, controls (CTRLs), patients with UNE and patients with generalized neuropathy (GNP). We first verified the anatomical superposition of the ulnar and median nerves in cadaver examination. The optimal recording site for these two nerves was found to be 10 cm above the medial epicondyle. We then standardized the position of the arm with full extension of the elbow and stimulated first the median and then the ulnar nerves at the wrist. CTRLs were examined on both arms at two consecutive visits. Results: We recorded 32 idiopathic UNE cases, 44 GNP patients and 62 controls. We demonstrated that a DLat cut-off value of 0.69 ms brings a sensitivity of 0.86 and specificity of 0.89 to discriminate CTRLs from UNE. We also validated that intra-examiner reproducibility was good. Conclusion: We report a lower normal value for DLat than reported in several non-standardized studies and CTRL and UNE groups have clearly separated DLat values. Significance: Due to its high sensitivity, our standardized technique could be used as a first-line diagnostic tool when UNE is suspected.