The brain is divided into white matter and gray matter, of which the white matter is the site where the axons of myelinated nerve fibers are assembled, and when myelin loss occurs, it causes demyelinating lesions in the white matter of the brain. The causes of myelin demyelination are two common categories: first, ischemic diseases, most patients are elderly, have hypertension, diabetes, hyperlipidemia and other underlying diseases, multiple atherosclerosis, some have stenosis and occlusion, resulting in small arterial endings ischemia, causing myelin malnutrition and demyelination. Second, it is inflammatory demyelination, with immune inflammation prevalent, often secondary to viral infection or combined with other autoimmune diseases, which leads to myelin damage due to specific antibodies attacking the antigens of myelin.