In order to be eligible to participate in this study, patient volunteers must meet all of the following criteria: Ability of subject to understand and the willingness to review an informed consent Aged at least 18 years at the time of enrollment, and no older than 90 years of age. Identity of dominant hand 1. Question: Which hand would you choose to hold the pen to write a formal letter? 2. Note: no specific answer is required for inclusion, but it is required for the next question. English-Speaking: Ability to type without discomfort using non-dominant hand Enrolled in the screening phase of Protocol 000089 Post-Coronavirus Disease 19 Convalescence at the National Institutes of Health in the post-COVID convalescence arm (i.e. reports having started recovery from an acute COVID- 19 infection within past six month and is able to provide documentation of a positive COVID-19 PCR or antibody test) In order to be eligible to participate in this study, healthy volunteers must meet all of the following criteria: Ability of subject to understand and the willingness to review an acknowledgement of participation agreement Aged at least 18 years at the time of enrollment, and no older than 90 years of age English-speaking Ability to identify dominant hand 1. Question: Which hand would you choose to hold the pen to write a formal letter? 2. Note: no specific answer is required for inclusion, but it is required for the next question. Ability to type without discomfort using non-dominant hand Deny active infection with COVID-19, or ongoing symptoms following COVID-19 infection Ability to use an internet-connected laptop or desktop computer in a private setting located in the continental U.S. to complete the study task. This protocol can enroll NIH Employees/staff, including NINDS employees/staff. Staff members from our section and their immediate family members are excluded from participation.

Patient group: A patient who meets any of the following criteria will be excluded from participation in this study: A condition prior to the diagnosis of COVID-19 infection that would significantly confound interpretation of the behavioral task, as determined by the screening clinician (e.g., prior diagnosis of a neurologic condition such as large stroke, Alzheimer s disease or Parkinson s disease, or severe psychiatric condition). Staff from our section, and their immediate family members Healthy Volunteer group: A person who meets any of the following criteria will be excluded from participation in this study: A condition that would significantly confound interpretation of the research tests as determined by the screening clinician (e.g., prior diagnosis of a neurologic condition such as large stroke, Alzheimer s disease or Parkinson s disease, or severe psychiatric condition) Fever, respiratory symptoms or diagnosis of COVID-19 in the last 14 days. History of COVID-19 with residual neurologic symptoms following diagnosis that did not resolve within 14 days of disease onset. Previous participation in this study (platform filter).