According to the clinical signs and symptoms of patients with smog, there are four main clinical manifestations of smog: 1. Transient ischemic attack, also called TIA type: it is the most common type of smog, accounting for about 70% of all episodes of smog, and is characterized by recurrent transient paralysis or weakness, mostly hemiparesis, or alternating right and left hemiparesis or double hemiparesis, with complete recovery of motor function after the attack. The course of the disease is mostly benign, with a tendency to spontaneous remission or complete cessation of attacks. Very few patients have hemiplegic seizures, headache or migraine, and, less commonly, transient sensory impairment, involuntary movement or mental retardation; 2. Infarct type: manifests as an acute stroke, resulting in persistent paralysis, aphasia, visual impairment and mental retardation; 3. Epileptic type: manifests as frequent convulsions, which can manifest as partial seizures or persistent status epilepticus. The EEG may be accompanied by epileptiform discharges on the EEG. 4. Cerebral hemorrhage: There may be subarachnoid hemorrhage or cerebral parenchymal hemorrhage, and adult patients are more likely to have this type than pediatric patients. The last three types are called “non-TIA type”, also known as non-transient ischemic attack type, with a complex and variable course and poor prognosis, mostly manifesting as mixed seizures, some patients have epilepsy and infarction, that is, convulsions and cerebral ischemia appear together, or have convulsions plus transient ischemic attacks, or can be manifested as simple seizures. It can also present as simple seizures. Regardless of the type, the prognosis is generally poor in patients with an onset before the age of 4 years. In addition, the clinical symptoms and their severity depend on the compensatory effect of the collateral circulation. If adequate cerebral blood flow is maintained, there may be no clinical symptoms or only transient ischemic attacks, or the patient may have only headaches, while if cerebral perfusion is not maintained, the patient’s symptoms will be more severe and extensive brain damage exists.