I. Definition of dementia: Dementia is a syndrome of acquired cognitive deficits caused by brain dysfunction. It is called dementia because it mostly develops in the elderly. Characteristics: 1. Brain dysfunction – caused by brain dysfunction, an organic disorder; 2. Acquired – not a congenital disease, but acquired due to various diseases; 3. Cognitive deficits – with memory and intelligence decline as the main manifestation. Dementia typology: There are three main categories according to the cause: 1. Dementia caused by brain degenerative diseases – Alzheimer’s disease dementia, also known as senile dementia, Alzheimer’s disease (AD) (mainly introduced Alzheimer’s disease dementia), Alzheimer’s disease dementia, Alzheimer’s disease dementia, Alzheimer’s disease dementia, Alzheimer’s disease dementia, Alzheimer’s disease dementia. Dementia), Alzheimer’s disease is the so-called Alzheimer’s disease. Alzheimer’s disease (AD) is a primary degenerative disease of the central nervous system that is characterized by deteriorating cognitive and memory functions, progressive decline in the ability to perform activities of daily living, and a variety of neuropsychiatric symptoms and behavioral disturbances. Although this disease can appear at any age, it usually appears between 60 and 70; 2. Dementia caused by cerebrovascular disease (Vascular Dementia, VaD for short); 3. Mixed Dementia (Mixed Dementia, MixD for short). It also includes dementia with Lewy body, frontotemporal dementia, Parkinson’s disease dementia, dementia caused by vitamin Bl2 and folic acid deficiency, etc. According to a survey in some urban areas in China, the prevalence of dementia in old age among people aged 60 and above is 4.2%. As the age increases, the prevalence rate gradually increases, and the prevalence rate is 20% in people over 80 years old. Alzheimer’s disease is most often seen in people over the age of 60, but it can also develop before the age of 50. Although the disease can appear at any age, it usually appears between 60 and 70. Mortality According to a survey published by the Alzheimer’s Disease Association of China in 2011, there are about 36.5 million people suffering from dementia worldwide, and one person suffers from the disease every seven seconds, with an average survival period of only 5.9 years. V. Cure rate From the current research and clinical observation, whether Chinese medicine or Western medicine treatment, can only relatively slow down the development of the disease, and can not fundamentally stop the process of the disease.