The difference between cognitive impairment and dementia, cognitive impairment is when a patient’s cognitive function decreases, but does not yet reach the level of dementia. The main way to determine whether a patient has reached dementia is to see if the patient’s social functions remain the same as before. For example, if the patient can still take care of himself/herself, still work and study, and still have normal social interactions with others, even if the patient has a decline in some parts of the cognitive field, it can only be called cognitive decline, not dementia. Alzheimer’s is more serious than cognitive impairment, which includes dementia, that Alzheimer’s is a serious stage. Alzheimer’s disease has a wide range of cognitive decline, accompanied by a significant decline in social function and the ability to take care of oneself in daily life. Patients can be considered to belong to Alzheimer’s disease if they have a decline in social function.