Implantable Vagus Nerve Stimulation Modulation of Coeruleus-Norepinephrine Network for Mild-Moderate AD Patients

Inclusion Criteria: 1. Referring to the NIA-AA clinical AD diagnostic criteria formulated by 2011 National Institute on Aging (NIA) and Alzheimer's Disease Association (ADA) groups, select mild to moderate AD patients with positive amyloid PET; 2. Male or female AD patients between the ages of 50-85; 3. Neuropsychological evaluation reaches the following standards: MMSE 16-24 points, CDR 0.5-2 points; 4. Patients who receives a stable cholinesterase inhibitor regimen continues the oral drug with the same dose for at least 8 weeks before entering the study 5. The patient has sufficient proficiency in Mandarin Chinese and is able to complete the cognitive assessment form; 6. Those who voluntarily accept the test and sign an informed consent form. Exclusion Criteria: 1. There is a clear history of cerebrovascular stroke, and there are clear symptoms or signs of neurological deficit at the time of onset, and there are corresponding responsible lesions left on neuroimaging; 2. Those with a history of alcoholism, or drug addiction, or neurological diseases that can cause cognitive impairment, such as traumatic brain injury, epilepsy, encephalitis, normal intracranial pressure hydrocephalus; 3. Suffering from systemic diseases that may lead to cognitive impairment (such as liver and kidney insufficiency, endocrine diseases, vitamin deficiency); 4. Suffering from cardiac conductive dysfunction (bradycardia) or sleep apnea syndrome; 5. Participating in other drug clinical trials; 6. There are contraindications to head MRI. 7. Those who are deemed unsuitable to participate the trial by the investigator.