Functional disorders as a common motor manifestation of COVID--19 infection or vaccination

Background and purpose: There have been over 500 million confirmed cases of severe acute respiratory syndrome coronavirus--2 (SARS--CoV--2), also known as coronavirus disease 2019 (COVID--19), across the globe. To date, a broad spectrum of neurological manifestations following acute infections as well as COVID--19 vaccines have been reported. The aim of this study was to describe the spectrum of neurological manifestations seen in the `COVID--19 clinic' established in a tertiary Movement Disorders clinic. Methods: In this consecutive case--series study over the period March 2020--January 2022, clinical information regarding demographic data, clinical history and examination findings, investigation results and video recordings of outpatients with motor manifestations associated with COVID--19 infection or vaccination were reviewed. Results: Twenty--one adult patients were reviewed in this ad hoc clinic at Toronto Western Hospital. The majority of the patients were female (76%) and the mean (range) age was 50.7 +/- 17.2 (21--80) years. Nine patients (43%) presented with motor manifestations following COVID--19 infection. Twelve patients (57%) developed neurological symptoms following at least one dose of the mRNA or viral vector--based COVID--19 vaccine. The most common manifestation observed was a functional movement disorder (43%). The vaccine group demonstrated a higher number of functional disorders compared to the infection group (58% vs. 22%; p = 0.08). Conclusion: Functional motor manifestations can be associated with COVID--19 and are likely to be under--reported. In view of the co--existence of functional symptoms, movement disorders and mental health conditions observed in this study, we would advocate the use of dedicated COVID--19 Neurology clinics with full access to an experienced multidisciplinary team.