The clinical neurophysiology of COVID-19-direct infection, long-term sequelae and para-immunization responses: A literature review

The COVID-19 pandemic resulting from the SARS-CoV-2 virus is in its third year. There is continuously evolving information regarding its pathophysiology and its effects on the nervous system. Clinical neurophysiology techniques are commonly employed to assess for neuroanatomical localization and/or defining the spectrum of neurological illness. There is an evolving body of literature delineating the effects of the SARS-CoV-2 virus on the nervous system as well as para-immunization responses to vaccination against this virus. This review focuses on the use of neurophysiological diagnostic modalities in the evaluation of potential acute and long-term neurological complications in patients that experience direct infection with SARS-CoV-2 and analyzes those reports of para-immunization responses to vaccination against the SARS-CoV-2 virus. The neurophysiological modalities to be discussed include electroencephalography (EEG), evoked potentials (EPs), nerve conduction studies and electromyography (EMG/NCV), autonomic function tests, transcranial magnetic stimulation (TMS) and Transcranial Doppler ultrasound (TCD)

Nerve conduction studies and EMG in carpal tunnel syndrome: Do they add value?

This paper summarises the views of four experts on the place of neurophysiological testing (EDX) in patients presenting with possible carpal tunnel syndrome, in guiding their treatment, and in reevaluations. This is not meant to be a position paper or a literature review, and heterogeneous viewpoints are presented. Nerve conduction studies should be performed in patients presenting with possible carpal tunnel syndrome to assist diagnosis, and may need to be repeated at intervals in those managed conservatively. There is evidence that local corticosteroid injection is safe and effective for many patients, thereby avoiding or deferring surgical decompression. All patients should undergo EDX studies before any invasive procedure for CTS (injection or surgery). Needle EMG studies are not obligatory, but may be needed in those with severe disease and those in whom an alternate or concomitant diagnosis is suspected. Keywords: Carpal tunnel syndrome, Median neuropathy at the wrist, Nerve conduction studies, Needle EMG, Surgical decompression, Local injection of corticosteroids, Conservative managemen

Murine central and peripheral nervous system transcriptomes: Comparative gene expression

The central and peripheral nervous systems exhibit significant embryological, morphological, and functional differences. Moreover, the pathology of most acquired and hereditary neurological diseases preferentially targets specific components of the nervous system. In order to test the hypothesis that central and peripheral neural transcriptomes show fundamental quantitative differences, Affymetrix GeneChip® expression arrays were used to compare murine lumbar spinal cord (SC) and dorsal root ganglion (DRG) gene expression. As the crucial component of a novel technique to preserve RNA integrity, mice were perfusion-fixed with RNAlater™ before the SC and DRG were harvested. As per Affymetrix terminology, a total of 111 transcripts were present (P) on all DRG arrays, absent (A) on all SC arrays, and demonstrated at least 10-fold greater expression in DRG than in SC. Conversely, a total of 112 transcripts were present on all SC arrays, absent on all DRG arrays, and showed at least 10-fold greater expression in SC than in DRG. For a subset of transcripts, quantitative real-time RT-PCR was used to corroborate and validate microarray results. Among those genes enriched in DRG, many belonged to a few distinct functional classes: G-protein coupled receptor-protein signaling pathways, potassium transport, sodium transport, sensory perception, and cell-surface receptor-linked signal transduction. In contrast, genes associated with synaptic transmission, organic acid transport, neurotransmitter transport, and circulation were enriched in SC. Notably, the majority of genes causally associated with hereditary neuropathies were highly enriched in DRG. These differential neural gene expression profiles provide a robust framework for future molecular and genetic studies of neuropathy and SC diseases. © 2006 Elsevier B.V. All rights reserved

Guillain-Barré syndrome after H1N1 vaccination in the United States: a report using the CDC/FDA Vaccine Adverse Event Reporting System (2009).

BACKGROUND: Although the Guillain-Barré syndrome (GBS) can be associated with the seasonal influenza vaccine, there is no definite evidence that GBS is associated with H1N1 influenza vaccination. The objective of this report is to study the occurrence and characteristics of GBS after H1N1 vaccine administration in the United States in 2009. METHODS: Data were acquired from the Vaccine Adverse Event Reporting System and supplemented by additional information obtained from the Center for Biologics Evaluation and Research, under the Federal Freedom of Information Act. RESULTS: A total of 62 individuals (mean age 46.51 ± 22.41 years), 33 of whom were men, developed GBS associated with the H1N1 influenza vaccination in 2009. Sixty GBS cases were reported within 6 weeks after vaccination, with 31 cases (50.0%) reported in the first 2 weeks. The estimated rate of occurrence of GBS was 6.2 cases per 10 million vaccinations, which is comparable to the rate of GBS in the general population. CONCLUSION: The higher rate of GBS reports in the first 6 weeks after H1N1 vaccination suggests that some GBS cases may be triggered by H1N1 vaccination. This warrants early recognition, treatment, and active surveillance in the postvaccination setting

Analysis of data from the CDC/FDA vaccine adverse event reporting system (1990-2009) on Guillain-Barre syndrome after hepatitis vaccination in the USA.

We used data from the Vaccine Adverse Event Reporting System, supplemented by additional data provided by the Center for Biologics Evaluation and Research, to identify 189 patients with Guillain-Barré syndrome (GBS) reported after hepatitis vaccination with a mean age of 30.65 years, affecting men and women equally. Among vaccinated patients, 133 (70%) developed GBS within six weeks, 30 (15.9%) after six weeks, and for the remaining 26 (13.7%), the time between GBS occurrence and vaccination was not specified. The reporting rate of post-hepatitis vaccine GBS is approximately 3.4 cases per one million vaccinations, which is in the range expected in the general population. The unbalanced distribution of reports in the first six weeks after vaccination suggests that some cases of GBS may be triggered by vaccination. Nonetheless, the low incidence of hepatitis vaccine-associated GBS, and the dramatic incidence reduction of hepatitis and its complications after vaccination, support the current guidelines for vaccination

Guillain-Barré Syndrome After Influenza Vaccination in the United States, a Report from the CDC/FDA Vaccine Adverse Event Reporting System (1990-2009).

OBJECTIVES: To determine the rate of Guillain-Barré syndrome (GBS) after administration of influenza vaccine in the United States and to provide further information about the characteristics and temporal profile of these incidents. METHODS: Data were acquired from the Vaccine Adverse Event Reporting System, supplemented by data from the Center for Biologics and Research under the Freedom of Information Act between 1990 and 2009. RESULTS: There were 802 cases (mean age, 54.72 ± 18.4 years) of GBS reported after influenza vaccination in the United States between 1990 and 2009. Among the 802 vaccinated patients with available data, 624 (77.8%) developed GBS within 6 weeks and 78 (9.7%) after 6 weeks, whereas these data were unavailable for the remaining 100 patients (13%). The reporting rate of post-influenza vaccine GBS was within the range expected in the general population or approximately 0.46 cases per million vaccinations. A non-Gaussian distribution of GBS within the first 6 weeks post-vaccination was noted, given that the peak incidence occurred in the second week. CONCLUSIONS: The incidence of post-influenza vaccine GBS is similar to the incidence of idiopathic GBS in the general population. Although the nonnormal distribution of post-vaccination GBS suggests that some cases may be triggered by vaccination, the greater risk of complications from influenza virus infections makes vaccination the first-line strategy for infection prevention and support the current guidelines on vaccination