Dementia in the elderly is medically known as Alzheimer's disease, which is categorized into mild, moderate, and severe stages. The clinical manifestations vary with the severity of the disease. Mild dementia primarily presents as memory impairment, starting with a decline in short-term memory, where patients often forget daily activities. For instance, they might forget the way home when they go out, forget to add salt when cooking, or forget to turn off the stove. Patients may also exhibit personality disorders, such as neglecting personal hygiene or not wanting to bathe. As the disease progresses to moderate dementia, besides worsening memory impairment, the patient's ability to work, learn new knowledge, and communicate with others significantly diminishes. There is a notable decline in previously acquired knowledge and skills, such as judgment and calculation abilities. They may also experience aphasia, apraxia, agnosia, and some patients may exhibit significant behavioral and psychological abnormalities. With further progression to severe dementia, patients may become emotionally detached, exhibit unpredictable crying or laughing, fail to recognize family members, lose verbal abilities, and even become unable to perform simple tasks such as dressing or eating. They may spend their days in bed, not speaking, and gradually lose contact with the outside world, ultimately leading to death.