Some people with epilepsy have atypical seizures and it is difficult to diagnose seizures based on clinical manifestations alone, so EEG is particularly important. Sometimes, one or two normal EEGs in the interictal period cannot completely exclude epilepsy, which requires repeated EEG examinations. Some people abroad have repeatedly done EEGs dozens of times to confirm epilepsy, and finally found epileptic waves. Sometimes repeated EEGs are also needed to determine the type of seizure and to look for epileptic foci. The EEG is also often done during the course of medication treatment or when the patient is ready to reduce medication to help determine the effectiveness of the medication and decide if it can be reduced. The EEG is non-invasive, can be performed in general hospitals, and is inexpensive, so it is often repeated during the diagnosis and treatment of epilepsy.