What can the neurological manifestations of COVID-19 tell us: a meta-analysis

BACKGROUND: Covid-19 became a global pandemic in 2019. Studies have shown that coronavirus can cause neurological symptoms, but clinical studies on its neurological symptoms are limited. In this meta-analysis, we aimed to summarize the various neurological manifestations that occurred in COVID-19 patients and calculate the incidence of various neurological manifestations. At the same time, we further explored the mechanism of nervous system injury and prognosis in COVID-19 patients in combination with their nervous system manifestations. This study provides a reference for early clinical identification of COVID-19 nervous system injury in the future, so as to achieve early treatment and reduce neurological sequelae. METHODS: We systematically searched all published English literature related to the neurological manifestations of COVID-19 from January 1, 2020, to April 30, 2021, in Pubmed, Embase, and Cochrane Library. The keywords used were COVID-19 and terminology related to the nervous system performance. All included studies were selected by two independent reviewers using EndNote and NoteExpress software, any disagreement was resolved by consensus or by a third reviewer, and the selected data were then collected for meta-analysis using a random-effects model. RESULTS: A total of 168 articles (n = 292,693) were included in the study, and the meta-analysis showed that the most common neurological manifestations of COVID-19 were myalgia(33%; 95%CI 0.30–0.37; I(2) = 99.17%), smell impairment(33%; 95%CI 0.28–0.38; I(2) = 99.40%), taste dysfunction(33%; 95%CI 0.27–0.39; I(2) = 99.09%), altered mental status(32%; 95%CI 0.22–0.43; I(2) = 99.06%), headache(29%; 95%CI 0.25–0.33; I(2) = 99.42%), encephalopathy(26%; 95%CI 0.16–0.38; I(2) = 99.31%), alteration of consciousness(13%; 95%CI 0.08–0.19; I(2) = 98.10%), stroke(12%; 95%CI 0.08–0.16; I(2) = 98.95%), dizziness(10%; 95%CI 0.08–0.13; I(2) = 96.45%), vision impairment(6%; 95%CI 0.03–0.09; I(2) = 86.82%), intracerebral haemorrhage(5%; 95%CI 0.03–0.09; I(2) = 95.60%), seizure(4%; 95%CI 0.02 -0.05; I(2) = 98.15%), encephalitis(2%; 95%CI 0.01–0.03; I(2) = 90.36%), Guillan-Barré Syndrome (GBS) (1%; 95%CI 0.00–0.03; I(2) = 89.48%). CONCLUSIONS: Neurological symptoms are common and varied in Covid-19 infections, and a growing number of reports suggest that the prevalence of neurological symptoms may be increasing. In the future, the role of COVID-19 neurological symptoms in the progression of COVID-19 should be further studied, and its pathogenesis and assessment methods should be explored, to detect and treat early neurological complications of COVID-19 and reduce mortality.