Introduction
The coronavirus disease 2019 (COVID-19), which has affected million people worldwide and has posed a serious health threat on a global scale, is caused by the positive-sense, enveloped, single-stranded RNA virus known as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) (1). The published evidence indicates that the virus can enter the central nervous system (CNS) through the olfactory nerve, most likely using axonal transport and transsynaptic transport. In addition, the hematogenous pathway and other ways have been identified as other ways by which the virus might enter the brain (2-4).
The effects of COVID-19 on the brain are becoming more obvious. According to recent research, the coronavirus may attack specific brain cells directly, decrease blood supply to brain tissue, or cause the creation of immune chemicals that can damage brain cells. Former studies also reported the complications including agitation, impaired consciousness, headache, and dizziness stemmed from COVID-19 infection (5). Thereafter recovery, alas, suffering from few adverse effects of this infection have also been shown, namely fatigue, anxiety, depression, and insomnia (6). Accordingly, impediment to memory, concentration, or attention has been reported over the acute phase, accounting for a third of participants (7).
Of note, COVID-19, in accordance with a study carried out in Oxford University, gives rise to shrinking the brain and diminishing grey matter in the areas controlling memory. By comparison with uninfected participants in this study, patients irrespective of afflicting with mild or sever COVID-19 have been shown to have noticeably impair episodic memory – which can be durable up to 6 months thereafter infection, and not to be able to sustain attention over time – being durable up to 9 months thenceforth infection. Not understanding the mechanisms that cause these cognitive impediment notwithstanding, these adverse events were pointed out hopefully to return predominantly to normal in most COVID-19 patients by 6-9 months after infection (8).