Transcranial direct current stimulation (0 mA for 30 minutes) will be delivered using electrode positions optimized by an AI-based simulation based on each participant's MR images.

The Wolf Motor Function Test (WMFT) is a validated assessment used to evaluate upper-extremity motor function in individuals with mild to moderate impairment following stroke or traumatic brain injury. The test is based on direct observation of the participant's performance.

The assessment consists of 19 tasks evaluating upper-extremity function. For items 1-15, performance time and functional ability are measured. Functional ability is rated on a 6-point scale from 0 (does not attempt the task) to 5 (normal performance), and task completion time is recorded with a maximum limit of 120 seconds per task.

Two additional items assess upper-extremity strength and grip strength. Additional analyses will include comparisons between dominant and non-dominant hands.

The Box and Blocks Test (BBT) is a standardized assessment used to evaluate upper-extremity gross manual dexterity and coordination. During the test, participants move wooden blocks one at a time from one compartment of a box to another over a partition using one hand.

The test is performed for 1 minute for each hand. The total number of blocks successfully transferred within the time limit is recorded as the score. If more than one block is moved at the same time, the additional blocks are not counted. Additional analyses will include comparisons between dominant and non-dominant hands.

The Modified Barthel Index (MBI) is a standardized assessment used to evaluate activities of daily living (ADL). The scale consists of 10 items assessing functional independence, including personal hygiene, bathing, feeding, toileting, stair climbing, dressing, bowel control, bladder control, ambulation (or wheelchair use), and transfers between a bed and chair.

Each item is scored according to the level of assistance required, with a total score ranging from 0 to 100. Lower scores indicate greater dependence in daily activities, while scores between 91 and 99 indicate minimal dependence. The MBI is widely used due to its reliability, sensitivity, and practicality for evaluating functional recovery and mobility in rehabilitation. Additional analyses will include comparisons between dominant and non-dominant hands.

Grip strength is measured to assess hand muscle strength of the affected and unaffected upper extremity. Participants squeeze a hand dynamometer with maximum effort, and the measured force is recorded as the grip strength value. Additional analyses will include comparisons between dominant and non-dominant hands.

Quality of life (QoL) will be assessed using the EQ-5D-5L, a standardized self-reported questionnaire. The instrument evaluates five dimensions of health status: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression.

Each dimension has five levels ranging from "no problems" (Level 1) to "extreme problems or inability to perform" (Level 5). Participants select the level that best describes their current health status, generating a health profile. The EQ-5D-5L will be used to compare changes in quality of life between the intervention and sham groups.

The cortical excitability of the area corresponding to the swallowing movement will be assessed by changes in the amplitude and latency of the MEPs by using transcranial magnetic stimulation (TMS).