Pitfalls in Using Electrophysiological Studies to Diagnose Neuromuscular Disorders

Abstract

Electrodiagnostic testing is used widely for the full characterization of neuromuscular disorders and for providing unique information on the processes underlying the pathology of peripheral nerves and muscles. However, such testing should be considered as an extension of anamnesis and physical examination, not as pathognomonic of a specific disease entity. There are many pitfalls that could lead to erroneous interpretation of electrophysiological study results when the studies are not performed properly or if they are performed in the presence of anatomical aberrations. The diagnostic reliability of electrodiagnostic studies can be improved and the associated pitfalls overcome if the physician is familiar with all of those possible pitfalls. In this article we discuss the most common and important pitfalls associated with electrodiagnostic medicine.

Platelet‐rich plasma ultrasound‐guided injection in the treatment of carpal tunnel syndrome: A placebo‐controlled clinical study

“…Although we used NCS at the initial pre‐injection stage to classify our patients as suffering from mild, moderate, or severe (which we excluded from the survey) CTS, we did not choose NCS as our final follow‐up monitoring tool. NCS is a subjective examination with a small but important rate of false positive and false negative findings (Koo, Cho, & Kim, ). According to Koo et al, such testing should be considered an extension of anamnesis and physical examination, rather than a pathognomonic finding of a specific disease entity ().…”

“…NCS is a subjective examination with a small but important rate of false positive and false negative findings (Koo, Cho, & Kim, ). According to Koo et al, such testing should be considered an extension of anamnesis and physical examination, rather than a pathognomonic finding of a specific disease entity (). Furthermore, this is a painful method that reproduces patient's symptoms, so that they often denied to undergo it for a second time (follow‐up period) after their first experience (prior to injection).…”

The significance of muscle echo intensity on ultrasound for focal neuropathy: The median- to ulnar-innervated muscle echo intensity ratio in carpal tunnel syndrome

“…Electromyography (EMG) is the gold standard for evaluating the denervation and reinnervation status of muscles in patients with peripheral neuropathy (Stevens, 1997;Werner and Andary, 2011). The site of the pathologic lesion in patients with radiculopathy can be assessed using a myotome map and EMG results, which can demonstrate abnormal muscle patterns (Coster et al, 2010;Koo et al, 2012). However, EMG can be uncomfortable for patients http due to the pain caused by needle insertion.…”

Cross‐sectional area reference values of nerves in the lower extremities using ultrasonography

“…High‐resolution ultrasonography permits direct assessment of extrinsic and intrinsic abnormalities of peripheral nerves, thus compensating for the limitations of electrodiagnostic studies . Although various ultrasonographic variables have been suggested for assessment of abnormalities of peripheral nerves, the most widely accepted variable is the cross‐sectional area (CSA), determined by positioning the probe perpendicular to the nerve.…”