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Transcranial Direct Current Stimulation for Long COVID Brain Fog and Fatigue (NEUROSTIM-LC)

19 de julio de 2026 actualizado por: David Morales Álamo, University of Las Palmas de Gran Canaria

The Impact of Transcranial Direct Current Stimulation on Quality of Life, Brain Fog, and Fatigue in Patients With Long COVID: Study Protocol of the NEUROSTIM-LC Study

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.

Descripción general del estudio

Descripción detallada

The NEUROSTIM-LC study is a prospective, single-arm, interventional before-and-after study designed to evaluate the feasibility, tolerability, and preliminary effects of transcranial direct current stimulation (tDCS) in patients with long COVID. The study will recruit adults aged 18 to 70 years diagnosed with long COVID according to World Health Organization criteria and presenting persistent fatigue and/or cognitive impairment commonly described as brain fog.

Participants will receive 30 sessions of tDCS delivered over consecutive weeks in a controlled clinical setting. Stimulation will be applied over the left dorsolateral prefrontal cortex, with the anode positioned at F3 according to the international 10-20 EEG system and the cathode over the contralateral supraorbital region. Each session will be delivered at 2 mA for 20 minutes. Sessions will be performed on weekdays under the supervision of trained healthcare professionals, and adherence, tolerability, and adverse effects will be monitored throughout the intervention period.

Assessments will be conducted at baseline and after completion of the intervention. Clinical outcomes will include health-related quality of life, fatigue, cognitive performance, sleep quality, anxiety and depression symptoms, and perceived symptom evolution. Neurobiological and physiological outcomes will include brain metabolism assessed by PET-CT, autonomic nervous system activity assessed by heart rate variability, exercise capacity assessed using the Ekblom-Bak submaximal cycle ergometer test, upper-limb muscle strength assessed by handgrip dynamometry, lower-limb neuromuscular performance assessed by countermovement jump testing, respiratory function, oxygen saturation, and routine blood biomarkers. Blood samples may also be stored for future analysis of inflammatory and oxidative stress markers.

The study aims to provide preliminary information on whether repeated tDCS may be associated with measurable improvements in fatigue, brain fog, quality of life, and physiological function in patients with long COVID. The findings will help inform the design of future controlled trials evaluating non-invasive neuromodulation strategies for persistent neurological and fatigue-related symptoms after COVID-19.

Tipo de estudio

Intervencionista

Inscripción (Estimado)

20

Fase

  • No aplica

Contactos y Ubicaciones

Esta sección proporciona los datos de contacto de quienes realizan el estudio e información sobre dónde se lleva a cabo este estudio.

Estudio Contacto

Copia de seguridad de contactos de estudio

Criterios de participación

Los investigadores buscan personas que se ajusten a una determinada descripción, denominada criterio de elegibilidad. Algunos ejemplos de estos criterios son el estado de salud general de una persona o tratamientos previos.

Criterio de elegibilidad

Edades elegibles para estudiar

  • Adulto
  • Adulto Mayor

Acepta Voluntarios Saludables

No

Descripción

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.

Plan de estudios

Esta sección proporciona detalles del plan de estudio, incluido cómo está diseñado el estudio y qué mide el estudio.

¿Cómo está diseñado el estudio?

Detalles de diseño

  • Propósito principal: Tratamiento
  • Asignación: N / A
  • Modelo Intervencionista: Asignación de un solo grupo
  • Enmascaramiento: Ninguno (etiqueta abierta)

Armas e Intervenciones

Grupo de participantes/brazo
Intervención / Tratamiento
Experimental: tDCS Intervention
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.
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.
Otros nombres:
  • tDCS
  • Estimulación cerebral no invasiva
  • EPTE Bipolar tDCS device

¿Qué mide el estudio?

Medidas de resultado primarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Change in EuroQol 5-Dimension 5-Level Questionnaire Score
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
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
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
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
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
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
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
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
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
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
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
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

Medidas de resultado secundarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Change in Brain Metabolism
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
Brain metabolism will be assessed using positron emission tomography-computed tomography (PET-CT). Changes from baseline to post-intervention will be evaluated.
Baseline and 3 days after completion of the 30-session tDCS intervention
Change in Heart Rate Variability
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
Autonomic nervous system activity will be assessed using heart rate variability (HRV) recorded under resting conditions. Time-domain, frequency-domain, and non-linear HRV indices will be evaluated to characterize changes in autonomic regulation.
Baseline and 3 days after completion of the 30-session tDCS intervention
Change in Endurance Capacity
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
Endurance capacity will be assessed using the Ekblom-Bak submaximal cycle ergometer test. Heart rate responses, perceived exertion, estimated maximal oxygen uptake, and internal load will be evaluated under standardized conditions.
Baseline and 3 days after completion of the 30-session tDCS intervention
Change in Handgrip Strength
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
Upper-limb muscle strength will be assessed using handgrip dynamometry. Participants will perform three maximal attempts, and the highest value will be used for analysis.
Baseline and 3 days after completion of the 30-session tDCS intervention
Change in Lower-Limb Neuromuscular Performance
Periodo de tiempo: Baseline and 3 days after completion of the 30-session tDCS intervention
Lower-limb neuromuscular performance will be assessed using the countermovement jump test performed on a force platform. Variables related to force and power production will be evaluated.
Baseline and 3 days after completion of the 30-session tDCS intervention
Tolerability of the tDCS Intervention
Periodo de tiempo: During each tDCS session throughout the 30-session intervention period
Tolerability of the tDCS intervention will be assessed during each stimulation session using session monitoring records and participant reports. Tolerability will be evaluated based on the number of completed tDCS sessions out of the 30 scheduled sessions and the participant's ability to complete each session without clinically relevant discomfort. A higher number of completed sessions indicates greater intervention tolerability
During each tDCS session throughout the 30-session intervention period
Adverse Effects Related to tDCS
Periodo de tiempo: During each tDCS session throughout the 30-session intervention period
Adverse effects related to tDCS will be monitored and recorded at each stimulation session. Potential adverse effects include tingling, itching, headache, discomfort, burning sensation, dizziness, or transient erythema at the electrode site. The presence, type, and severity of adverse effects will be documented. Severity will be classified as mild, moderate, or severe.
During each tDCS session throughout the 30-session intervention period

Colaboradores e Investigadores

Aquí es donde encontrará personas y organizaciones involucradas en este estudio.

Investigadores

  • Investigador principal: Juan Francisco Vigueras, MD, Canary Islands Health Service

Fechas de registro del estudio

Estas fechas rastrean el progreso del registro del estudio y los envíos de resultados resumidos a ClinicalTrials.gov. Los registros del estudio y los resultados informados son revisados ​​por la Biblioteca Nacional de Medicina (NLM) para asegurarse de que cumplan con los estándares de control de calidad específicos antes de publicarlos en el sitio web público.

Fechas importantes del estudio

Inicio del estudio (Estimado)

15 de septiembre de 2026

Finalización primaria (Estimado)

22 de diciembre de 2027

Finalización del estudio (Estimado)

1 de marzo de 2028

Fechas de registro del estudio

Enviado por primera vez

11 de julio de 2026

Primero enviado que cumplió con los criterios de control de calidad

11 de julio de 2026

Publicado por primera vez (Actual)

16 de julio de 2026

Actualizaciones de registros de estudio

Última actualización publicada (Actual)

22 de julio de 2026

Última actualización enviada que cumplió con los criterios de control de calidad

19 de julio de 2026

Última verificación

1 de julio de 2026

Más información

Términos relacionados con este estudio

Información sobre medicamentos y dispositivos, documentos del estudio

Estudia un producto farmacéutico regulado por la FDA de EE. UU.

No

Estudia un producto de dispositivo regulado por la FDA de EE. UU.

No

Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .

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