Transcranial Direct Current Stimulation for Long COVID Brain Fog and Fatigue

NCT07709234 | Not Yet Recruiting DMC

• 2 other identifiers: NEUROSTIM-LC-2026CGC-2025-10415
• Study Type: interventional
• Target: 20
• Locations: 0 countries
• Sites: N/A

Brief Summary

Long COVID can cause persistent symptoms such as fatigue, cognitive difficulties commonly described as brain fog, reduced exercise tolerance, and impaired quality of life. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that may help modulate brain activity in regions involved in cognition, fatigue, and executive function. The NEUROSTIM-LC study will evaluate the feasibility and potential effects of repeated tDCS sessions in adults with long COVID presenting fatigue and/or brain fog. Participants will receive 30 sessions of tDCS applied over the left dorsolateral prefrontal cortex. Assessments will be performed before and after the intervention to evaluate changes in quality of life, fatigue, cognitive function, brain metabolism, physical performance, autonomic function, sleep quality, psychological symptoms, respiratory function, and blood biomarkers.

Conditions

Cognitive Dysfunction; Long COVID; Post-COVID Conditions; Fatigue

Keywords

Transcranial direct current stimulation; tDCS; Brain fog; Long COVID; Chronic Fatigue; Quality of life; Cognitive impairment; Heart rate variability; PET-CT; Neuromodulation

Outcome Measures

Primary Outcomes (6)

• Change in EuroQol 5-Dimension 5-Level Questionnaire Score

  Health-related quality of life will be assessed using the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5L). The EQ-5D-5L assesses five health dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression, each rated across five levels of severity. Higher scores or index values reflect better health status, depending on the scoring method used. Changes from baseline to post-intervention will be evaluated.

  Baseline and 3 days after completion of the 30-session tDCS intervention

• Change in Modified Fatigue Impact Scale Score

  Fatigue will be assessed using the Modified Fatigue Impact Scale (MFIS). The MFIS assesses the impact of fatigue on physical, cognitive, and psychosocial functioning. The total score ranges from 0 to 84, with higher scores indicating greater fatigue impact. Changes from baseline to post-intervention will be evaluated.

  Baseline and 3 days after completion of the 30-session tDCS intervention

• Change in Montreal Cognitive Assessment Score

  Global cognitive function will be assessed using the Montreal Cognitive Assessment (MoCA). The MoCA evaluates cognitive domains including attention, memory, language, visuospatial abilities, executive function, abstraction, calculation, and orientation. The total score ranges from 0 to 30, with higher scores indicating better cognitive performance. Changes from baseline to post-intervention will be evaluated.

  Baseline and 3 days after completion of the 30-session tDCS intervention

• Change in Short Form-36 Health Survey Score

  Health-related quality of life will be assessed using the Short Form-36 Health Survey (SF-36). The SF-36 evaluates eight domains of health-related quality of life: physical functioning, role limitations due to physical health, role limitations due to emotional problems, energy/fatigue, emotional well-being, social functioning, pain, and general health. Scores are transformed to a 0-100 scale, with higher scores indicating better health-related quality of life. Changes from baseline to post-intervention will be evaluated.

  Baseline and 3 days after completion of the 30-session tDCS intervention

• Change in Verbal Fluency Task Performance

  Verbal fluency will be assessed using verbal fluency tasks. Performance will be evaluated based on the number of correct words generated within the specified time period. Higher scores indicate better verbal fluency performance. Changes from baseline to post-intervention will be evaluated.

  Baseline and 3 days after completion of the 30-session tDCS intervention

• Change in Stroop Test Performance

  Executive function, inhibitory control, and cognitive flexibility will be assessed using the Stroop test. Performance will be evaluated using test-specific measures such as response accuracy and/or completion time. Better performance is reflected by higher accuracy and/or shorter completion time, depending on the scoring method used. Changes from baseline to post-intervention will be evaluated.

  Baseline and 3 days after completion of the 30-session tDCS intervention

Secondary Outcomes (7)

• Change in Brain Metabolism

  Baseline and 3 days after completion of the 30-session tDCS intervention

• Change in Heart Rate Variability

  Baseline and 3 days after completion of the 30-session tDCS intervention

• Change in Endurance Capacity

  Baseline and 3 days after completion of the 30-session tDCS intervention

• Change in Handgrip Strength

  Baseline and 3 days after completion of the 30-session tDCS intervention

• Change in Lower-Limb Neuromuscular Performance

  Baseline and 3 days after completion of the 30-session tDCS intervention

Study Arms (1)

tDCS Intervention

EXPERIMENTAL

Participants will receive 30 sessions of transcranial direct current stimulation applied over the left dorsolateral prefrontal cortex. Stimulation will be delivered at 2 mA for 20 minutes per session, once daily, five days per week, under supervision of trained healthcare professionals.

Device: Transcranial Direct Current Stimulation

Interventions

Transcranial Direct Current Stimulation DEVICE

Transcranial direct current stimulation will be delivered using a constant-current stimulator through surface electrodes placed over the scalp. The anode will be positioned over the left dorsolateral prefrontal cortex, corresponding to F3 according to the international 10-20 EEG system, and the cathode will be placed over the contralateral supraorbital region. Each session will be delivered at 2 mA for 20 minutes. Participants will complete 30 sessions.

Also known as: tDCS, Non-invasive brain stimulation, EPTE Bipolar tDCS device

tDCS Intervention

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• University of Las Palmas de Gran Canaria: lead
• Canary Islands Health Service: collaborator
• Fundación Canaria Instituto de Investigación Sanitaria de Canarias: collaborator

MeSH Terms

Conditions

Post-Acute COVID-19 Syndrome; Fatigue; Cognitive Dysfunction; Mental Fatigue

Interventions

Transcranial Direct Current Stimulation

Condition Hierarchy (Ancestors)

COVID-19; Pneumonia, Viral; Pneumonia; Respiratory Tract Infections; Infections; Virus Diseases; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Lung Diseases; Respiratory Tract Diseases; Post-Infectious Disorders; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Cognition Disorders; Neurocognitive Disorders; Mental Disorders; Behavioral Symptoms; Behavior

Intervention Hierarchy (Ancestors)

Electric Stimulation Therapy; Therapeutics; Convulsive Therapy; Psychiatric Somatic Therapies; Behavioral Disciplines and Activities; Electroshock; Psychological Techniques

Study Officials

• Juan Francisco Vigueras, MD

  Canary Islands Health Service

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Juan Francisco Vigueras, MD

CONTACT

+34 606 63 86 98; juanfraviguerasperez@yahoo.es

David Morales Álamo, PhD

CONTACT

+34 623 062 814; david.moralesalamo@ulpgc.es

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Masking Details: No masking will be used. This is a single-arm open-label study without a sham or control group.
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Model Details: Prospective single-arm before-and-after interventional study. All participants will receive transcranial direct current stimulation and will be assessed before and after the intervention.

Study Record Dates

• First Submitted: July 11, 2026
• First Posted: July 16, 2026
• Study Start (Estimated): September 15, 2026
• Primary Completion (Estimated): December 22, 2027
• Study Completion (Estimated): March 1, 2028
• Last Updated: July 22, 2026

Record last verified: 2026-07