I. What is dementia? Dementia is a syndrome of persistent, acquired intellectual impairment caused by various reasons. In layman’s terms, it means that the patient used to have normal intelligence, but due to some reasons, the intelligence declines, involving memory, language, judgment, comprehension, etc., which seriously hinders daily and social life. This decline in intelligence is long-term and continuous, and transient intelligence impairment caused by drugs or diseases cannot be diagnosed as dementia. Surveys show that the prevalence of dementia in people over 65 years of age is about 6%, and the prevalence increases with age, doubling with every 5 years of age, reaching 27% in people over 85 years of age. As society ages, the number of people with dementia is increasing rapidly. Patients’ social and self-care abilities are severely reduced, requiring long-term care by family members, which seriously affects the lives of patients and their families, and has become a major medical and health problem worldwide. What are the common symptoms of dementia? The clinical manifestations of dementia are mainly three parts: intellectual impairment, mental and behavioral symptoms, and diminished daily ability. 1.Intelligence impairment Intelligent impairment is the core symptom of dementia, including memory impairment, language impairment, diminished perception, orientation impairment, diminished calculation power, and attention impairment, etc. (1) Memory impairment The early stage of dementia mostly involves prograde memory, which is manifested by the inability to recall recent events, such as the content of conversation, TV programs, the last meal eaten, forgetting the location of things, forgetting to take medication or things to be purchased, repeatedly saying one sentence or one thing, such as just asking the guest “How are your parents?” and then asks the same thing again. As the disease progresses, the patient’s distant memory is also affected in the middle stage, forgetting the early events in life, when the patient often has nothing to say and very little to remember, and the conversation is often limited to one or two things that are often done. (2) Language impairment Patients with early dementia mostly show difficulty in finding words, hesitation, and hollow language, and as the disease progresses, they eventually develop into complete aphasia, with the patient being silent or only mumbling, and completely unable to understand and express. (3) Decline in ability to use The ability to use is significantly reduced in the middle and late stages of dementia, gradually appearing to be unable to flush in the bathroom, unable to dress or undress, easily scattered meals, and needing care in life. (4) Decrease in perceptual ability As the disease progresses, to the moderate stage, the patient cannot recognize the right and left side, and cannot recognize his or her own fingers. In severe cases, patients cannot recognize the faces of their relatives and do not recognize themselves in the mirror. (5) Disorientation Early in dementia, both severe temporal disorientation can occur, and the patient does not know what year, month, day, or season it is. As the disease progresses, the orientation of places and people is gradually impaired, and the patient does not know where he or she is and cannot distinguish the identity of people. (6) Calculation impairment Early in dementia, the ability to calculate is diminished, and the patient is unable to perform more complex calculations, such as 60 cents for a catty of cabbage and 3 yuan and 60 cents for several catties. As dementia progresses to the middle and late stages, patients are unable to perform very simple calculations such as 2+3, 1+2, etc. correctly. 2. Diminished daily functioning Due to the impairment of intelligence, the patient’s ability to work is diminished, for example, he or she may miscalculate accounts, or the teacher may give a wrong lecture, forcing him or her to give up work. Some patients are apparently able to work, but these jobs are usually simple and programmed (e.g. warehouse keeper, etc.), and once new problems arise in the work or the job requirements change, the patient is unable to perform. Patients are unable to count accounts, do shopping, go out of town, move around the area where they live, or perform simple household tasks. In the early stage, the patient’s basic daily living skills such as eating, dressing and undressing, washing, getting in and out of bed, going up and down stairs, and bowel and urine control are still normal. In the middle stage, patients do not know how to urinate and defecate in a timely manner, often soiling their pants, often soiling their tops and spilling meals on the table. Severe patients need to be taken care of for eating, dressing, urinating and defecating. 3.Mental behavior symptoms Mental behavior symptoms are common in patients with dementia. Mental symptoms include hallucinations, delusions, apathy, diminished will, restlessness, depression, agitation, paranoia, and sleep disorders. Behavioral abnormalities include wandering, hyperactivity, aggression, violence, hiding things, overeating, and omnivorous eating. Some patients have significant personality changes, and people who were previously very generous can become selfish and inconsiderate of their families. Psycho-behavioral symptoms have serious adverse consequences for patients and caregivers and are one of the main reasons why patients with dementia are seen or hospitalized.