Cognitive Impairment and Fatigue After Mild to Moderate COVID-19

Inclusion Criteria: • Persons 18 years and older with a history of (\> 3 months) verified COVID-19 (PCR / rapid test / antibody) or an infection that is most likely a SARS-CoV-2 infection (e.g., a close relative had a verified infection that coincided in time with the patient's illness) and who have persistent problems with cognitive impairment or fatigue affecting the return to previous activities / employment. Exclusion Criteria: * Dominant recurrent and / or fluctuating symptoms of infection, circulatory, respiratory or cardiac problems. * Co-morbidities that may cause cognitive impairment such as neurodegenerative disease, substance abuse, severe mental illness (eg. schizophrenia, mano depressive disorder) or severe depression. * Not fluent in Swedish, as test and self-reports rely on good mastering of the Swedish language. * Severe premorbid visual impairment. Additionally for the fMRI study: * Not verified SARS-CoV-2 infection with a Polymerase Chain Reaction (PCR) / rapid test / antibody review * Traumatic brain injury * Neuropsychiatric disease such as diagnosed ADHD or autism * Younger than 25 years or older than 55 years (to avoid the risk that the brain is not fully developed or that there is a risk of age-related changes in the brain). * MRI contraindications (such as metal objects in the body, fear of cramped spaces, pregnancy, body weight over 130 kg), and left-handedness (to increase the likelihood of uniform topological lateralization in the cohort).