One of the important problems of modern neurology is the study of dementia. The increase in the number of older people and the change in their age index has led to an increase in the number of older people with cognitive impairment and dementia. Studies show that the cause of memory loss in people over 65 is Alzheimer's disease (AD). Until now, complete information about the cause and course of Alzheimer's disease has not been provided. The accuracy of diagnosis is low in the early stages of the disease, especially in the pre-clinical stages.