Cognitive and neurological effects of the COVID-۱۹, An updated systematic reviews

The third novel coronavirus to emerge, in ۲۰۱۹, is called COVID-۱۹. It chiefly affects the respiratory system; However, there are reports of coronaviruses causing cognitive and neurological manifestations. The aim of this study was to systematic review the evidence regarding cognitive and neurological effects of the COVID-۱۹, as well as its direct and indirect effects.We conducted a systematic literature search from December ۲۰۱۹ to ۲۰۲۱ January. The articles were searched in the databases including PubMed, Scopus, Web of sciences (WOS) and Google Scholar, the Scientific Information Database (SID) as a national database. They included articles with cases of COVID-۱۹ where neurological involvement was evident. The total of ۴۷ articles were selected. According to the inclusion criteria, ۳۹ articles were regarded as appropriate. There were ۲۷ review articles, ۷ original studies and ۳ case reports, from January ۲۰۲۰ to December ۲۰۲۰. Fatigue, headache, and smell/taste disorders and anosmia were common neurological manifestations and also cerebrovascular disorders such as ischemic stroke, encephalopathies, post-infectious immune-mediated complications such as Guillain-Barre syndrome and acute disseminated encephalomyelitis and seizures were reported in patient with COVID-۱۹. In experimental studies, IL-۶, TNFα and IL-۱β cytokines were introduced as key elements for etiology of COVID-۱۹ induced long- term cognitive impairments.The review suggests that although more articles have reported cognitive and neurological effects; However, many items remain unclear and ambiguous. So, there is a need to diagnose and investigation their biological background of these manifestations at the earliest to limit long term sequelae.

Keywords:

Cognitive disorders , Neurological effects , Coronavirus , COVID-۱۹ , SARS-CoV-۲ , Systematic review