Science News: The Value of Sensory Nerve Conduction Studies in the Diagnosis of Guillain-Barré Syndrome

Submitted by: Elliot Bodofsky, MD
Edited by: Pritikanta Paul, MD

Freiha J, Zoghaib R, Makhoul K, et al. The value of sensory nerve conduction studies in the diagnosis of Guillain-Barré syndrome. Clin Neurophysiol. 2021;132(5):1157-1162. doi:10.1016/j.clinph.2021.02.013

Summary: Detecting Guillain-Barré syndrome (GBS) early is important for effective treatment. Present electrodiagnostic criteria are exclusively based on motor studies, although sensory testing abnormalities occur early in most patients. This article reviews the utility of sensory testing for GBS. Specifically, sural sensory sparing, i.e. abnormal median and ulnar SNAPs (sensory nerve action potential) amplitudes and normal sural SNAP, is 47-83% sensitive and up to 96% specific for GBS. Likewise, one study indicated an abnormal (dorsal ulnar/palmar ulnar) SNAP ratio of less than 0.78 is 87% sensitive and 100% specific for GBS. Sensory abnormalities can also be seen with axonal forms of GBS, and are predominant in the sensory variants.

Comments: Guillain-Barré syndrome is a very common indication for electrodiagnostic testing. Early diagnosis is crucial for effective treatment. Present diagnostic criteria can be suboptimal, particularly in early stages. The addition of upper and lower extremity sensory nerve conduction testing can improve diagnostic accuracy. Sural sparing and low (dorsal/palmar) ulnar sensory ratios are helpful diagnostic criteria for GBS.

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Umapathi T, Lim CSJ, Ng BCJ, Goh EJH, Ohnmar O. A Simplified, Graded, Electrodiagnostic Criterion for Guillain-Barré Syndrome That Incorporates Sensory Nerve Conduction Studies [published correction appears in Sci Rep. 2020 Jan 14;10(1):618]. Sci Rep. 2019;9(1):7724. Published 2019 May 22. doi:10.1038/s41598-019-44090-w