EEG is one of the important tools in the diagnosis of neurological diseases, and many patients need EEG for the following reasons: 1. Differential diagnosis of seizure disorders. Because there are a lot of strange seizure disorders within the nervous system, such as sudden falls, flailing movements, mental behavioral abnormalities, and other such sudden movements. When we identify them, many times we need to use the EEG to determine whether the EEG has abnormal discharges, such as whether it is epilepsy, etc., we are to further differential diagnosis; 2. For the diagnosis of epilepsy. EEG has an irreplaceable role in the diagnosis of epilepsy. When epileptic patients have seizures, they are often accompanied by abnormal discharges in the EEG, so when we are judging whether a patient is epileptic or not, we need to capture the abnormal discharges in his brain by doing EEG. If there are abnormal discharges, basically we can judge the epileptic seizure; 3. For the judgment of brain function. Because the EEG is constantly changing as a child grows older, the EEG at different ages has its own characteristics. Therefore, we can judge the brain function status and whether it is consistent with the age by doing EEG. Sometimes for some mentally retarded children, EEG can also help to determine their intelligence; 4. In the intensive care unit, it is used to determine brain death. Some children are in the unresponsive state, often should be further treatment, how to judge, often we need to do EEG to judge, to see whether he is in brain death, this still has a more important role in the judgment of brain death.