EEG Feedback-Based Vagus Nerve Stimulation for Post-Stroke Dysphagia

The goal of this clinical trial is to learn if electroencephalogram (EEG) biofeedback-guided transcutaneous auricular vagus nerve stimulation (taVNS) works to treat swallowing difficulties (dysphagia) in adults after a stroke. It will also learn about the safety of this rehabilitation method and how it helps the brain recover. The main questions it aims to answer are: 1. Does EEG biofeedback-guided taVNS improve the ability to eat and drink by mouth? 2. What medical problems (adverse events) do participants have during the treatment? Researchers will compare EEG biofeedback-guided taVNS (where gentle electrical stimulation to the outer ear is paired with surface brainwave monitoring during swallowing exercises) to conventional taVNS (where electrical stimulation is given at fixed times) to see which method better improves swallowing function. Participants will: 1. Receive standardized swallowing rehabilitation training for at least 30 minutes a day, 5 days a week for 2 weeks. 2. Practice swallowing imagery exercises with non-invasive surface EEG biofeedback monitoring while receiving gentle taVNS on the outer ear for 20 minutes a day, 5 days a week for 2 weeks. 3. Complete swallowing tests, questionnaires, and brain evaluations before treatment, after the 2-week treatment, and at Week 4 for follow-up.

Inclusion Criteria: 1. Age 18 to 80 years old, willing to participate and sign written informed consent. 2. First-ever acute ischemic stroke, or recurrent stroke with no prior history of dysphagia; diagnosis conforming to the 2023 Chinese Guidelines for Diagnosis and Treatment of Acute Ischemic Stroke. 3. Confirmed unilateral cerebral hemisphere (cortical or subcortical) infarction by cranial MRI or CT, in the subacute stage (2 weeks to 6 months post-stroke). 4. Objectively confirmed oropharyngeal dysphagia verified by videofluoroscopic swallowing study (VFSS); Gugging Swallowing Screen (KWST) \>= grade 3. 5. Right-handed. 6. Mini-Mental State Examination (MMSE) score \>= 22, conscious and stable, capable of understanding and cooperating with evaluations and treatments. 7. Basic motor imagery cognitive ability: assessed by the Kinesthetic and Visual Imagery Questionnaire (Short Version) (KVIQ-10) with a total score \>= 25, and a mean item score \>= 3 for the Kinesthetic subscale. Exclusion Criteria: 1. History of other neurological diseases causing dysphagia (e.g., Parkinson's disease, motor neuron disease), structural abnormalities or surgical history of the oral cavity/pharynx/esophagus, or history of head and neck tumors or radiotherapy. 2. Presence of any metallic implants or electronic devices in the body (e.g., cardiac pacemaker, deep brain stimulator, cochlear implant, aneurysm clip). 3. Personal or family history of epilepsy. 4. Severe aphasia (especially sensory aphasia) or cognitive impairment preventing the understanding and execution of simple motor imagery or action commands. 5. Tracheotomy status. 6. Intolerance to videofluoroscopic swallowing study (VFSS) or prolonged electroencephalogram (EEG) examinations. 7. Unstable vital signs, including severe infection, fever, uncontrolled arrhythmia, bleeding tendency, or severe medical conditions of the heart, liver, or kidneys. 8. Previous experimental treatments for post-stroke dysphagia (e.g., other forms of neuromodulation therapy) since the stroke onset. 9. Severe visual or hearing impairment preventing the clear viewing or hearing of screen-based motor imagery instructions.