The incidence of Alzheimer’s disease has increased significantly due to the aging of the population, changes in social lifestyles, and an increase in the incidence of cerebrovascular diseases. According to epidemiological data, the prevalence of dementia in foreign countries is 2.2% to 8.4% in people over 65 years old, and the prevalence increases exponentially with age in people aged 60 to 90 years old, i.e., it increases by one time every 5.1 years. Domestically, the prevalence of dementia is 2.9% for those aged 55 and older, 5.22% for those aged 65 and older, and about 40% of those aged 80 and older have varying degrees of dementia. You may have complained that you or your elderly family members often experience memory loss or loss of memory, and you may be wondering whether this is simple senile memory loss (forgetfulness) or dementia. First, we must understand what dementia is. This is important. Dementia is an acquired (not natural), persistent, multiple cognitive deficit. It is characterized by impairments in memory, language, visuospatial function, cognitive and mental domains. Senile dementia is a group of diseases with dementia as the main clinical manifestation in old age (≥65 years) due to various etiologies. The main clinical manifestations of dementia include the following: memory impairment, behavioral changes, visuospatial skills impairment, impaired judgment and distraction, writing difficulties, loss of use and recognition, dyscalculia, language impairment, psychiatric and personality changes, and motor impairment. Of these, impairment of near-matter memory is mandatory, along with at least 2-3 other domains of cognitive dysfunction. Diagnostic criteria for dementia: 1. Presence of multiple cognitive dysfunctions: Memory impairment (mainly episodic memory) is the core symptom of dementia. >2-3 other domains of cognitive dysfunction. 2. Severity of cognitive deficits: significantly affects daily life, occupational function and social activities. This is an important basis for distinguishing amnesia or mild cognitive impairment. 3.Cognitive dysfunction is progressive or stepwise aggravated with a disease duration >6 months. 4.No impairment of consciousness. 5, Cognitive impairment is not limited to the delirium phase. If it coexists with delirium, the cognitive deficit persists after the symptoms of delirium disappear. When you or your family members have this condition, you should promptly go to the relevant hospital department (neurology, psychiatry) for consultation. Let the specialist perform neuropsychological examination and related scales (such as MMSE, MoCA, BBS, WAIS-RC, HIS, CDR, etc.), as well as neuroimaging examinations such as cranial CT or MRI, blood biochemistry, etc., in order to find out the possible causes of dementia.