This clinical study aims to evaluate the efficacy and safety of spinal cord stimulation combined with non-invasive motor imagery brain-computer interface rehabilitation training in patients with upper limb motor dysfunction after chronic stroke. The study includes an experimental group receiving spinal cord stimulation combined with motor imagery brain-computer interface rehabilitation training and a control group receiving motor imagery brain-computer interface rehabilitation training alone. The primary outcome is upper limb motor function assessed by the Fugl-Meyer Assessment for Upper Extremity. Secondary outcomes include muscle tone, upper limb functional activity, activities of daily living, adverse events, serious adverse events, and exploratory neurophysiological and neuroimaging indicators.

Upper limb motor dysfunction is a common and disabling sequela of stroke. Many patients enter a chronic phase more than 6 months after stroke onset, during which spontaneous recovery and conventional rehabilitation-related improvement often reach a plateau. Motor imagery brain-computer interface rehabilitation can decode motor intention from electroencephalographic signals and provide closed-loop feedback through external devices, thereby promoting cortical reorganization. However, in patients with impaired corticospinal pathways and insufficient residual motor execution capacity, the efficacy of motor imagery brain-computer interface training alone may be limited.

Spinal cord stimulation may facilitate spinal motor circuits, reduce abnormal muscle tone, and improve the excitability of residual descending motor pathways. Combining spinal cord stimulation with motor imagery brain-computer interface training may provide a synergistic central-peripheral neuromodulation strategy. The brain-computer interface decodes motor intention from the central nervous system, while spinal cord stimulation facilitates peripheral motor pathway execution, potentially enhancing motor recovery and neuroplasticity.

Participants will be assigned, according to patient preference and investigator assessment, to either the experimental group or the control group. The experimental group will undergo spinal cord stimulation implantation followed by individualized stimulation programming and standardized motor imagery brain-computer interface rehabilitation training. The control group will receive the same frequency and duration of motor imagery brain-computer interface rehabilitation training without spinal cord stimulation implantation. Clinical outcomes will be assessed at baseline, after 4 weeks of intervention, 2 months after intervention, and 3 months after intervention. Safety events will be recorded throughout the study. Exploratory assessments will include electroencephalography and neuroimaging to investigate potential mechanisms of neuroplasticity.

Inclusion Criteria:

• Age 18 to 75 years.
• First-ever unilateral supratentorial stroke, either ischemic or hemorrhagic, confirmed by computed tomography or magnetic resonance imaging, resulting in hemiparesis, with disease duration longer than 6 months.
• At least one active movement in the wrist or fingers of the affected upper limb, with muscle strength of grade 1 or higher.
• Fugl-Meyer Assessment for Upper Extremity score between 10 and 40, indicating moderate upper limb motor impairment.
• Change in Fugl-Meyer Assessment score less than 10% within the previous month, indicating a functional plateau.
• Clear consciousness and basically normal cognitive function, with Mini-Mental State Examination score of 24 or higher.
• Stable clinical condition and ability to understand and cooperate with simple instructions and rehabilitation training.
• Written informed consent voluntarily signed by the participant or legal guardian.

Exclusion Criteria:

• Other neurological diseases that may cause motor dysfunction, such as Parkinson's disease, multiple sclerosis, or spinal cord injury.
• Severe visual or auditory impairment that prevents cooperation with visual or auditory feedback instructions of the brain-computer interface system.
• Contraindications to spinal cord stimulation surgery, such as severe coagulation dysfunction, infection at the puncture site, severe spinal deformity, or spinal canal stenosis.
• History of epilepsy, intracranial metal implants, cardiac pacemaker, or other contraindications to magnetic resonance imaging.
• Previous neuromodulation surgery for hemiparesis, such as spinal cord stimulation or deep brain stimulation.
• Pregnancy or lactation.
• Any other condition judged by the investigator to make the participant unsuitable for this study.