The diagnostic criteria for Alzheimer’s disease are as follows: 1. It should meet the diagnostic criteria for dementia, such as cognitive function affecting the ability to perform daily life, his ability to live a life of decline, unable to take care of himself; 2. The diagnosis of dementia can be made by two of these conditions, such as memory, learning ability, visual-spatial ability, executive function, and language function; 4. We must obtain the evidence and basis provided by the informant to show that the patient has cognitive impairment; 5. We must exclude other diseases, especially the diseases of senile dementia, such as vascular dementia, frontotemporal dementia, Lewy body dementia and other diseases.