Stroke patients often experience impaired balance and weight-bearing due to muscle weakness and neurological deficits. Motor rehabilitation is a crucial goal in their recovery, and transcranial direct current stimulation (tDCS) has emerged as a promising therapeutic approach. When combined with motor training, tDCS can enhance walking and balance abilities. However, there is a lack of research exploring the combination of unstable surfaces training, cognitive function, and tDCS for stroke rehabilitation

Stroke is a leading cause of long-term disability worldwide, often resulting in impaired motor function, reduced walking ability, decreased muscle strength, and cognitive deficits. These limitations contribute to difficulties in activities of daily living, impaired balance, and reduced quality of life. Effective rehabilitation strategies are essential to promote functional recovery and reduce the risk of long-term dependence.

Transcranial direct current stimulation (tDCS) has emerged as a promising non-invasive neuromodulation technique to facilitate cortical excitability and enhance neuroplasticity in individuals with stroke. Anodal stimulation over the lesioned hemisphere has been shown to improve motor performance and cognitive processing, while sham stimulation does not induce comparable effects. Recent studies suggest that combining tDCS with task-specific rehabilitation programs may provide synergistic benefits by simultaneously enhancing neural activation and functional task performance.

Dual-task training, particularly stepping exercises performed on unstable surfaces, has been demonstrated to challenge both motor and cognitive systems simultaneously. This approach targets balance, gait adaptation, and executive function by requiring patients to divide attention between locomotion and cognitive demands. When applied in combination with tDCS, dual-task training may enhance neuroplasticity and strengthen functional outcomes beyond those achieved by conventional training alone.

The present randomized controlled trial is designed to investigate the combined effects of anodal tDCS and dual-task stepping exercise on unstable surfaces in stroke survivors. Participants will be randomized into three groups: (1) active tDCS combined with dual-task stepping, (2) dual-task stepping with sham tDCS, and (3) active tDCS alone. Interventions will be delivered three times per week for four weeks.

Primary outcomes will include measures of functional ability, walking speed, walking endurance, lower limb muscle strength, and cognitive ability. Secondary outcomes will explore the effects of combined stimulation on balance and overall motor recovery. It is hypothesized that participants receiving combined anodal tDCS and dual-task training will demonstrate greater improvements in both motor and cognitive outcomes compared with either intervention alone.

This study will contribute novel evidence to stroke rehabilitation research by addressing the knowledge gap regarding the integration of non-invasive brain stimulation with cognitive-motor dual-task training on unstable surfaces. The findings are expected to provide insights into effective multimodal rehabilitation strategies aimed at improving functional recovery and quality of life in stroke survivors.

Inclusion Criteria:

• Volunteers were diagnosed with cerebrovascular disease, aged 18 years and above, both male and female.

1.1.2. Body mass index between 18.5-29.9 kg/m2 1.1.3. No history of falls in the 6 months prior to the study. 1.1.4. Able to follow instructions and consent to participate in the study. 1.1.5. Able to communicate with the researcher and provide information by themselves.

1.1.6. Able to walk continuously for at least 10 meters safely.

Exclusion Criteria:

• 1.2.1 Having undergone surgery to insert metal implants in the body, such as pacemakers, deep brain electrodes.

1.2.2 High blood pressure, uncontrolled heart disease, or having underlying diseases, such as osteoarthritis, arthritis, such as gout, rheumatoid arthritis, severe and affecting treatment.

1.2.3 Having a wound on the skull and abnormal sensation. 1.2.4 Having a history of injury or pain in the extremities. At a pain score of more than 5 out of a full score of 10, assessed by (Visual Analog Scale) 1.2.5 There is a condition of the inner ear that is disturbed, affecting balance, such as tinnitus.

1.2.6. There are unresolved vision and hearing problems. 1.3 Criteria for withdrawing volunteers from the research 1.3.1 If a volunteer experiences pain or discomfort during the test, the test will be stopped and the volunteer will be removed from the research immediately.

1.3.2 The volunteer requests to withdraw or is unwilling to continue the research.