Table 1.

Inclusion and exclusion criteria.

Inclusion Criteria	Exclusion Criteria
Age from 30 to 60 years	Less than 30 and more than 60 years
Mild form of COVID-19 disease	Severe or critical COVID-19 disease
Neurological symptoms: anosmia, dysgeusia, vertigo, headache, vertigo, fatigue	Severe neurological symptoms: acute cerebrovascular disease (ischemic or hemorrhagic stroke, subarachnoid hemorrhage), encephalopathy, encephalitis, meningitis, polyneuropathy, seizures, disturbance of consciousness
COVID-19 disease: from 290 to 310 days from infection start	COVID-19 disease: less than 290 or more than 310 days from infection start
Supportive therapy only	Antibiotics, corticosteroids, or oxygen use for COVID-19 infection
COVID-19 disease confirmation: positive real-time reverse PCR test, positive nasal/pharyngeal swabs test	Uncontrolled diabetes mellitus or arterial hypertension, cerebrovascular disease, hematologic disease, atrial fibrillation, chronic heart disease, cancer
	Severe alcohol consumption (more than 10 drinks per week)
	Stenosis of extracranial vertebral or carotid artery >20% or occlusive disease of intracranial cerebral arteries
	Using anticoagulant therapy, vasodilatory drugs, hormone replacement therapy, β-blocking agents, calcium channel blockers

PCR—polymerase chain reaction.