Dementia in Alzheimer’s disease is a progressive neurodegenerative disease with an insidious onset. Clinically, it is characterized by comprehensive dementia manifestations such as memory impairment, aphasia, apraxia, agnosia, visual-spatial skill impairment, executive dysfunction, and personality and behavioral changes. The cause is still unknown. In the past, patients who developed the disease before the age of 65 were called presenile dementia, and patients who developed the disease after the age of 65 were called senile dementia. The main pathological changes of this disease are cerebral cortical atrophy, neurofibrosis, brain nerve cell degeneration and senile plaques. It is a common disease in the elderly.