EEG: EEG is a curve of electrical activity of the brain recorded by placing appropriate electrodes and amplifying the bioelectrical activity of brain cells one million times with the help of electronic amplification technology. EEG is the most important tool for the diagnosis of epilepsy and seizures, and is also an important basis for the “international classification” of epilepsy and seizures, as well as a reference for determining the response to treatment and for reducing and stopping medication. However, the diagnosis of epilepsy should not be based solely on the presence of epileptiform discharges on the EEG. A normal EEG does not mean that epilepsy can be ruled out. When the discharges are hidden or rare, it is difficult to record them on the EEG. Therefore, standardized EEG examinations should be performed, including various activation (evoked) tests, extended EEG recording time, and EEG recording under special conditions (different sleep depths). 2. Cranial CT: It can detect more obvious structural abnormalities, but it is difficult to detect subtle structural abnormalities. It is mostly used in cases of epilepsy emergencies, suspected intracranial calcifications, hemorrhagic lesions, inability to perform magnetic resonance (MRI) examinations, etc. MRI of the head: It has been widely used in clinical diagnosis and treatment planning of epilepsy, and has largely improved the prognosis of epilepsy patients. MRI has a high spatial resolution and can detect some subtle structural abnormalities, and has a high reference value for etiologic diagnosis, especially for the evaluation of refractory (intractable) epilepsy. A variety of different imaging techniques and sequences have been used in clinical testing, and their diagnostic significance varies for structural abnormalities (lesions) of different nature, such as those seen specifically in hippocampal sclerosis, focal cortical dysplasia, cavernous hemangioma, nodular sclerosis, cerebral surface angiomatosis, smoker’s disease, and mitochondrial encephalopathy. In general, it is recommended that an epilepsy specialist design the cranial MRI examination protocol for the patient. 4. Neuropsychological examination: Many patients with epilepsy are accompanied by intellectual and psychiatric behavioral abnormalities, which need to be evaluated with specialized methods. The diagnosis of certain epileptic syndromes and epileptic encephalopathies requires the support of neuropsychological examination results. In patients who undergo preoperative evaluation for epilepsy, neuropsychological assessment not only helps to localize the epileptogenic focus, but also helps to evaluate the changes in various brain functions before and after surgery. 5. Head PET: It can quantify the biochemical processes in specific functional brain areas and can be interpreted as an examination of brain cell activity, such as testing the brain’s use of glucose and the distribution of different neuroactive substances. In the localization of “epileptic foci”, the tracer marker currently used clinically is 2-deoxyglucose (FDG), which is used to observe local metabolic changes in the brain. In general, the cortical metabolism (or mobility) is reduced in non-seizure (also known as interictal) foci, while seizure periods show high metabolism. In addition PET examination can help to detect microscopic lesions that are difficult to detect by MRI. 6. Other laboratory tests: hematological tests including routine blood, blood glucose, electrolytes, and blood calcium can help to find the cause of the disease. Blood concentration monitoring of antiepileptic drugs helps in drug adjustment and detection of drug toxicity, etc. Hematological examination is also used for the detection of adverse drug reactions, and common monitoring indicators include blood routine, liver and kidney function and electrolytes, etc. Seizures are one of the main manifestations of genetic metabolic disorders. Blood and urine genetic metabolic screening can help diagnose the etiology of epilepsy. A portion of epilepsy is genetically related, especially certain specific types of epilepsy, and genetic screening is needed to confirm the diagnosis and to complete further genetic counseling and guidance.