The efficacy and mechanisms of transcutaneous auricular vagus nerve stimulation in patients with post-stroke cognitive impairment: a preliminary study

INTERVENTION: Part ?: Group A:Stimulation of the left ear followed by the right ear;Part ?: Group 2:Stimulation of the right ear followed by the left ear;Part II: experimental group:Basic treatment + ta‐VNS treatment;Part II: control group:Basic treatment + sham ta‐VNS treatment;Part III: healthy subjects:taVNS treatment;Part III: Patient group:taVNS treatment; CONDITION: stroke PRIMARY OUTCOME: Addenbrooke's Cognitive Examination Scale; SECONDARY OUTCOME: Montreal Cognitive Assessment Scale;Auditory Verbal learning test;digit span test;Executive interview 25(Chinese version);Shape trail making test;Dysexecutive Questionnaire;Frontal Assessment Battery;9‐item Patient Health Questionnaire Depression Scale;7‐item Generalized Anxiety Disorder Scale;Modified Barthel index;Functional magnetic resonance imaging;fNIRS;EEG; INCLUSION CRITERIA: Part I: 1. Age =18 years old and =75 years old, both sexes, right‐handed; 2. No cognitive impairment was assessed by mini‐mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA); 3. The 9‐item Patient Health Questionnaire depression scale showed no depression; 4. Activities of daily living scale (modified barthel index) showed normal activities; 5. Agree to participate in this study and sign the informed consent form. Part II: 1. Meet the diagnostic criteria for stroke; (2) First onset, duration =1 month and =6 months, stable vital signs; 3. Age =18 years old and =75 years old, both sexes, right‐handed; 4. Right‐handed, primary school or above education; 5. Montreal cognitive assessment (MoCA) score > 10 and < 26;6. Native speaker of Chinese, able to complete the test in listening and comprehension; 7. Subjects and their legal guardians (if necessary) understand and agree to participate in this study and sign an informed consent form. Part I