Inclusion Criteria:

• Participants must be 18 years or older.
• Participants must understand and cooperate with requirements of the study in the opinion of the investigators and must be able to provide written informed consent.
• Individuals who had no known COVID-19 exposure (for controls) or had PCR or antibody confirmed COVID-19 who present with neurological symptoms in the months after infection and fit one of the following criteria during the acute phase of the infection:
  • ambulatory with no or mild symptoms;
  • hospitalized but on no oxygen; or
  • hospitalized but on oxygen administered via a nasal cannula, mask or non-invasive ventilation; i.e., individuals with WHO Ordinal Scale40 scores 0-5. 
• English or Spanish speaking (based on self-stated primary language).
• Clear of any contraindications for MRI.

Exclusion Criteria:

• Patients under 18 years of age.
• Medical conditions likely to interfere with the study, including chronic neurologic conditions, restless leg syndrome, structural abnormalities such as subdural hematoma, intracranial neoplasms, end-stage renal disease, severe chronic obstructive pulmonary disease (COPD) needing oxygen, end-stage liver disease, active psychiatric illness, active drug abuse, stroke unrelated to COVID-19 or heart attack 6 months before study enrollment, active cancer, concurrent illnesses or treatments interfering with cognitive function such as dementia or normal pressure hydrocephalus.
• Individuals who had COVID-19 and required mechanical ventilation.
• Pregnant women.
• Inability to undergo MRI scanning, including but not limited to claustrophobia, unable to remain still in an MRI scanner for more than 30 minutes, presence of paramagnetic substances or pacemakers in body, weight over 300 lbs.
• Inability to adhere to study protocol for whatever reason.