Electrophysiological features of acute inflammatory demyelinating polyneuropathy associated with SARS-CoV-2 infection

Antonino Uncini, Camillo Foresti, Barbara Frigeni, Benedetta Storti, Maria Cristina Servalli, Stefano Gazzina, Giuseppe Cosentino, Francesca Bianchi, Ubaldo Del Carro, Enrico Alfonsi, Stefano Cotti Piccinelli, Giovanni De Maria, Alessandro Padovani, Massimiliano Filosto, Luigi Ippoliti

Research output: Contribution to journalArticlepeer-review


OBJECTIVE: To assess whether patients with acute inflammatory demyelinating polyneuropathy (AIDP) associated with SARS-CoV-2 show characteristic electrophysiological features.

METHODS: Clinical and electrophysiological findings of 24 patients with SARS-CoV-2 infection and AIDP (S-AIDP) and of 48 control AIDP (C-AIDP) without SARS-CoV-2 infection were compared.

RESULTS: S-AIDP patients more frequently developed respiratory failure (83.3% vs. 25%, P=0.000) and required intensive care unit (ICU) hospitalization (58.3% vs. 31.3%, P=0.000). In C-AIDP, distal motor latencies (DMLs) were more frequently prolonged (70.9% vs. 26.2%, P=0.000) whereas in S-AIDP distal compound muscle action potential (dCMAP) durations were more frequently increased (49.5% vs. 32.4%, P=0.002) and F waves were more often absent (45.6% vs. 31.8%, P=0.011). Presence of nerves with increased dCMAP duration and normal or slightly prolonged DML was elevenfold higher in S-AIDP (31.1% vs. 2.8%, P=0.000);11 S-AIDP patients showed this pattern in 2 nerves.

CONCLUSION: Increased dCMAP duration, thought to be a marker of acquired demyelination, can also be oserved in critical illness myopathy. In S-AIDP patients, an increased dCMAP duration dissociated from prolonged DML, suggests additional muscle fiber conduction slowing, possibly due to a COVID-19-related hyperinflammatory state. Absent F waves, at least in some S-AIDP patients, may reflect α-motor neuron hypoexcitability because of immobilization during the ICU stay. These features should be considered in the electrodiagnosis of SARS-CoV-2 patients with weakness, to avoid misdiagnosis.

Original languageEnglish
Pages (from-to)183-191
Number of pages9
JournalNeurophysiologie Clinique
Issue number2
Publication statusPublished - Mar 2021


  • Action Potentials
  • Adult
  • Aged
  • Aged, 80 and over
  • COVID-19/complications
  • Critical Care/statistics & numerical data
  • Electrodiagnosis
  • Electrophysiological Phenomena
  • Female
  • Guillain-Barre Syndrome/etiology
  • Hospitalization/statistics & numerical data
  • Humans
  • Male
  • Middle Aged
  • Motor Neurons
  • Muscle, Skeletal/physiopathology
  • Neural Conduction
  • Respiratory Insufficiency/etiology
  • Sensory Receptor Cells


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