Electrophysiological assessment in patients with COVID-19 related peripheral neuropathies: A systematic review

Background: Neurological manifestations associated with Coronavirus Disease-2019 (COVID-19) are commonly reported, but patients were not referred to perform the electrophysiological assessment. Aim: we aimed to review the existing literature on clinical studies on COVID-19 peripheral neuropathy to correlate patients' symptoms and characteristics with nerve conduction studies/electromyography (NCS/EMG) outcomes. Methods: This protocol is registered in the Open Science Framework (OSF) (DOI: 10.17605/OSF.IO/ZF4PK.). The systematic search included PubMed, ScienceDirect, and Google Scholar, for articles published from December 2019 to March 2022. A total of 727 articles were collected, and according to our inclusion and exclusion criteria, only six articles were included. Results: Of 195 participants, only 175 underwent NCS/EMG assessment. Of these: 44 participants (25.1%) had abnormal EMG, 54 participants (30.8%) had abnormal motor NCS, and only 7 participants (4%) had abnormal sensory NCS. All cases presented with myopathy, while a limited number of cases presented with polyneuropathy. According to motor NCS and EMG, the most affected nerves were the tibial and peroneal in the lower extremities and the ulnar nerve in the upper extremities. Interestingly, the median nerve was reported to be associated with the severity and the rate of motor recovery of COVID-19 patients. Conclusion: COVID-19 generates a demyelinating motor neuropathy and myopathy. Clinicians are encouraged to refer COVID-19 patients presenting with neurological symptoms to be assessed by electrophysiological methods to objectively determine the nature of their symptoms, follow their prognosis, and plan their rehabilitation.