DAOIB for the Treatment of Brain Fog

This is a 24-week open trial. We will enroll long-COVID patients with cognitive impairments. All patients will receive DAOIB for 24 weeks. We will assess the patients every 8 weeks during the treatment period (weeks 0, 8, 16, and 24). We hypothesize that DAOIB treatment will be beneficial in improving the cognitive function, mood symptoms, global functioning and quality of life in long-COVID patients with cognitive impairments.

Inclusion Criteria: * "post-COVID-19 condition" defined by WHO (symptoms present at three months after SARS-CoV-2 infection and last for at least 2 months which cannot be explained by an alternative diagnosis)(Cabrera Martimbianco, Pacheco et al. 2021) and COVID-induced cognitive impairments * physically healthy and have all laboratory assessments (including urine/blood routine, biochemical tests, and electrocardiograph) within normal limits * have sufficient education to communicate effectively and are capable of completing the assessments of the study Exclusion Criteria: * history of significant cerebrovascular disease * Hachinski Ischemic Score \> 4 * major neurological, psychiatric or medical conditions other than long COVID-induced cognitive impairments * memantine use (memantine is an NMDAR partial antagonist) * substance (including alcohol) abuse or dependence * delusion, hallucination or delirium symptoms * severe visual or hearing loss * inability to follow the protocol