Clinical Research Directory

Inclusion Criteria: * Adults aged between 18 and 70 years. * Diagnosis of long COVID according to World Health Organization criteria, defined as symptoms persisting for at least three months after acute SARS-CoV-2 infection and lasting for a minimum of two months without an alternative explanation. * Presence of persistent fatigue and/or cognitive impairment, commonly described as brain fog, attributed to long COVID and confirmed at screening. * Stable clinical condition allowing participation in the intervention and assessment procedures. * Ability to understand the study procedures and provide written informed consent. Exclusion Criteria: * Contraindications to transcranial direct current stimulation, including the presence of implanted electronic devices such as pacemakers or neurostimulators, intracranial metallic implants, or history of epilepsy or seizures. * History of neurological disorders that may affect cognitive function, including stroke, Parkinson's disease, or neurodegenerative disorders. * Pre-existing conditions associated with chronic fatigue or cognitive impairment prior to SARS-CoV-2 infection, such as fibromyalgia, chronic fatigue syndrome, or multiple sclerosis. * Severe psychiatric disorders, including psychosis or severe depression. * Substance abuse, including alcohol or drugs. * Current oncological treatment with chemotherapy or radiotherapy. * Pregnancy. * Any medical condition that, in the opinion of the investigators, may interfere with participation or with the interpretation of the results.