Effect of tDCS Timing on Motor Recovery in Acute Stroke Rehabilitation

Timing Matters: Comparing Pre , Peri , and Post Rehabilitation tDCS in Acute Stroke Recovery

This randomized, double-blind, sham-controlled clinical trial investigates how the timing of transcranial direct current stimulation (tDCS) influences functional recovery during acute stroke rehabilitation. 198 hospitalized patients with confirmed acute stroke will be randomly assigned to one of three groups. Each day, all participants will receive three tDCS sessions: one before, one during, and one after their rehabilitation session. In each group, only one of these three daily stimulations is active, while the other two are sham, allowing a direct comparison of timing effects while maintaining blinding. All participants will complete 2 sets of five consecutive days of conventional rehabilitation combined with the tDCS protocol (2 weeks). Functional, sensory, psychological, and motor outcomes will be assessed at baseline and at the end of the intervention week. The study aims to determine whether the timing of tDCS application influences early post-stroke recovery and to inform the design of future confirmatory trials.

Inclusion Criteria:

• Hospitalization for stroke rehabilitation Hospitalized in a stroke rehabilitation unit at CHU de Liège.

Confirmed acute stroke Diagnosis of acute stroke (ischemic or hemorrhagic) confirmed by neuroimaging, according to local clinical practice.

Time since stroke In the acute/subacute phase, as defined in the protocol (e.g., within X days/weeks after stroke onset) - to be specified exactly as in your protocol.

Age Age ≥ 18 years.

Capacity to consent Able to understand the study information and provide written informed consent.

Motor impairment of the upper limb Presence of motor deficit of the upper limb on the affected side, sufficient to perform the WMFT tasks (according to protocol thresholds, if specified).

Medically stable Clinically stable and judged by the treating physician as able to participate in daily rehabilitation and tDCS sessions.

Exclusion Criteria:

• Contraindications to tDCS or cranial stimulation

Implanted electronic devices in the head or neck (e.g., deep brain stimulator, cochlear implant, implanted neurostimulator, pacemaker with leads near the head).

Metal implants in the skull (excluding dental fillings) in the area of stimulation.

Large skull defect or craniectomy over the stimulation site.

History of seizures History of epilepsy or unprovoked seizures not adequately controlled, if considered a contraindication to tDCS by the investigator.

Severe cognitive or communication impairment Severe cognitive impairment, aphasia, or comprehension difficulties preventing understanding of the study or execution of the tasks, as judged by the investigator.

Severe comorbidities Unstable medical conditions (e.g., uncontrolled cardiac, respiratory, metabolic, or systemic disease) that could interfere with participation or increase risk.

Severe psychiatric disorder Current severe psychiatric illness (e.g., psychosis, severe untreated major depression) that may affect cooperation or safety, as judged by the investigator.

Skin conditions at electrode sites Skin lesions, infections, severe dermatitis, or wounds at or near the planned electrode placement sites.

Concurrent participation in another interventional trial Participation in another interventional clinical trial that could interfere with the outcomes or safety of this study.

Pregnancy Pregnancy or breastfeeding, if considered a contraindication according to local tDCS safety policy (optional, depending on your protocol stance).

Any other reason Any condition or circumstance that, in the opinion of the investigator, makes the patient unsuitable for the study or unable to comply with the protocol.