What is dementia? Dementia is a syndrome caused by a brain disease, usually chronic or progressive in nature, with disturbances in multiple higher cortical functions, including impairment of memory, thinking, orientation, comprehension, computation, learning, language and judgment, but without blurring of consciousness. It is often accompanied by impairment of cognitive function, occasionally preceded by a decline in emotional control, social behavior, or social motivation. This syndrome can occur in Alzheimer’s disease, cerebrovascular disease, and other primary or secondary conditions affecting the brain. It has the following characteristics: 1. Dementia is most often seen in people over the age of 60, but it can also be acquired before the age of 50. 2. Alzheimer’s is a chronic disease that often starts with mild memory loss and slowly develops severe brain damage. 3.After suffering from Alzheimer’s disease, patients can survive for 8-10 years on average, and with the continuous development of medicine, the life expectancy of Alzheimer’s disease will gradually increase.