Neurophysiological and Behavioral Effects of Combining Transcranial Direct Current Stimulation (tDCS) and Modified-Constraint Induced Movement Therapy (mCIMT)

This clinical trial aims to evaluate the effect of different types of tDCS modulation with mCIMT in improving affected upper-limb motor function for stroke patients. The main question it seeks to answer:

Which type of tDCS (bi-hemispheric, anodal, or cathodal) combined with the mCIMT program leads to greater improvement in affected upper-limb function in patients with stroke? Researchers will compare these three types of tDCS to a sham tDCS. To see which kind of tDCS protocol combined with the mCIMT program will be more effective in improving affected upper-limb function for stroke patients.

Participants will:

1. Participants will receive 12 sessions of mCIMT combined with tDCS or mCIMT alone.
2. Visit the clinic three times a week for four weeks.
3. Participants will do fMRI and TMS before and after the program and three times of assessment before and after two weeks after the program.

Background: After a stroke, intense motor rehabilitation is required to facilitate motor recovery. In specific, combining tDCS with neurorehabilitation interventions boosts the responses of the brain to the interventions and maximizes the effects of rehabilitation to improve upper limb recovery post-stroke. Objectives: To evaluate the effect of different modes of tDCS modulation with mCIMT in improving affected upper-limb motor recovery for patients with stroke. Method: a randomizing control trial design, after performing a baseline assessment, the participants will be randomly assigned to one of the four groups: the anodal tDCS +mCIMT group, the cathodal tDCS +mCIMT group, the bihemispheric tDCS +mCIMT group, and the mCIMT alone group. Inclusion Criteria, adult participants clinically diagnosed and confirmed by imaging of ischemic or hemorrhagic cerebrovascular accident, participant's age older than 18 years, Stroke onset more than 3 months with unilateral motor deficits, Adequate cognitive function is required to follow instructions. The Arabic version of the Mini-Mental State Examination (MMSE) should be ≥24, 10° of active extension to the metacarpophalangeal and interphalangeal joints and 20° at the wrist, and not participating in other clinical, or research studies at the same time. Exclusion Criteria, Severe muscle spasticity at the affected limb at all joints (the Modified Ashworth Scale scores \> 3), Contraindications to NIBS, unilateral neglect, Other neurologic or orthopedic conditions that may affect hand function, and unstable medical conditions. The total intervention period will be performed 3 times a week for 4 weeks. Each participant will undergo motor impairment and physiological assessments at baseline, during and after the intervention. Functional outcome measures: Fugl-Meyer Assessment Scale - upper extremity (FMA-UE), Wolf Motor Function Test (WMFT), Nine-Hole Peg Test (NHPT), Arabic version of Stroke Impact Scale (SIS-16), and Stroke-Specific Measure of Adherence to Home-based Exercises (SS-MAHE). Physiological outcome measures: Cortical Excitability Assessment will be measured by Transcranial Magnetic Stimulation (TMS) with electromyographic (EMG) and functional magnetic resonance imaging (fMRI).

Eligibility Criteria:
Inclusion Criteria:

1. Adult participants clinically diagnosed and confirmed by imaging of ischemic or hemorrhagic cerebrovascular accident (Dahl et al., 2008; Jin et al., 2019).
2. Participant's age older than 18 years (Baltar et al., 2020).
3. Stroke onset more than 3 months with unilateral motor deficits (Lin et al., 2010).
4. Adequate cognitive function is required to follow instructions. The Arabic version of the Mini Mental State Examination (MMSE) should be ≥24 (Kim, 2021).
5. 10° of active extension to the metacarpophalangeal and interphalangeal joints and 20° at wrist will be assessed by manual goniometer (Dahl et al., 2008).
6. Fugl-Meyer assessment (FMA) scores between 19 and 58, indicating moderate to mild impairments.
7. Not participating in other clinical, or research studies at the same time.

Exclusion Criteria:

1. Severe muscle spasticity at the affected limb at all joints (the Modified Ashworth Scale scores \> 3) (Baltar et al., 2020).
2. Contraindications to NIBS (Bornheim et al., 2019).
3. Unilateral neglect (Dahl et al., 2008)
4. Other neurologic or orthopedic conditions that may affect hand function.
5. Unstable medical conditions.