Dementia is a syndrome caused by a brain disease that causes hu progressive mental decline, memory loss or loss, abnormal behavior, personality changes and emotional disturbances. As far as we know, there are more than 100 kinds of diseases that can cause dementia. Mainly include: I. Degenerative diseases such as Alzheimer’s disease, Pick’s disease, Huntington’s disease, cerebellar degeneration, olive bridge cerebellar degeneration, adrenoleukodystrophy, etc. II. Cerebrovascular disease multiple infarcts dementia, subcortical atherosclerotic leukoencephalopathy, cortical micro-infarction, amyloidosis vascular and cerebral embolism of various causes, such as fat, air, and thrombotic cerebral embolism. . Severe cerebral hypoxia such as carbon monoxide poisoning, severe cardiac insufficiency and sudden cardiac arrest. iv. Traumatic brain injury Various types of traumatic brain injury. v. Infectious diseases of the brain such as AIDS, progressive multifocal leukoencephalopathy, dementia after cerebral for, neurosyphilis, and cerebral abscess. vi. Positive pressure hydrocephalus. vii. Demyelinating diseases Multiple sclerosis, systemic lupus erythematosus. viii. Intracranial placebo disorders Primary tumors of the brain or metastatic tumor. Especially tumors in the midline. Toxic diseases Alcohol poisoning, heavy metal poisoning, organophosphorus or organic solvent poisoning. Drugs such as sedatives, antidepressants, antiarrhythmic drugs, antihypertensive drugs, anticonvulsants and antipsychotics, etc. XI. Nutritional disorders such as vitamin B1 and vitamin B12 deficiency, folic acid deficiency, etc., and corpus callosum degeneration, etc. XII. Metabolic disorders Hyperthyroidism, hypothyroidism, hypercalcemia, hypernatremia, hyponatremia, hyperlipidemia, hypercarbia, renal insufficiency, hepatic insufficiency, hyperfunction, and hypercarbohydria. , renal insufficiency, hepatic insufficiency, hypopituitarism, distant effects of tumors, etc. xiii. myoclonic epilepsy, psychosis, and other genetic disorders.