June 28 is the International Epilepsy Care Day, and this year’s theme is “Doctors and Patients Working Together to Overcome Epilepsy”. Currently, there are about 60 million epilepsy patients in the world. Wang Liyao, director of the Department of Neurology at Shenyang No. 5 People’s Hospital, said that EEG is of great value to the diagnosis of epilepsy, and has become an indispensable examination method for diagnosis and typing. The human brain is capable of emitting measurable electrical currents as well as other living tissues in the body, such as the skin, muscles, and heart. The heart can have an electrocardiogram, and likewise the brain has an electroencephalogram. A normal person’s cerebral cortex fully matures at the age of 13-14 years, at which time it has a normal rhythmic pattern of spontaneous brain electrical activity, rather than disorganized electrical activity. Once the EEG pattern is established, it is relatively stable in each individual, and even though there are day-to-day variations, the overall pattern, including the average wave rate and wave amplitude, changes over time in much the same way. Capturing Abnormal EEG Changes The neurons in the brain of an epileptic patient may have abnormal discharges that are different from those of a normal person during the interictal period, and when these discharges are widely spread and cause a group of neurons in the surrounding area to synchronize and discharge abnormally, a seizure is caused. This abnormal discharge both during the seizure and interictal period may cause EEG changes, there will be different from the normal when the manifestation of the graph, the changes that occur is what we often say may see epileptiform waves appeared, such as spiking waves, sharp waves, spiking slow wave syndrome, spiking slow wave synthesis, and other explosive rhythms such as spike wave, slow wave syndrome, and other explosive rhythms, the reason why epileptic patients need to undergo EEG examination, is to capture this kind of abnormal EEG changes. If the patient has a very clear seizure presentation and such abnormal EEG changes are found, then a definitive diagnosis of epilepsy is made. Further identification of the type of seizure and the site of the epileptogenic focus must also be based on the EEG and provide a basis for the choice of medication. In patients with first seizures, the likelihood of subsequent seizure recurrence can be evaluated. Other scholars believe that EEG can help to determine the response to treatment and provide reference for patients to reduce or stop medication. For some seizure disorders similar to epilepsy that need to be excluded from the diagnosis of epilepsy, EEG is even more important. This all stems from the fact that EEG captures head-specific changes in patients with epilepsy that cannot be replaced by other tests. 80% of patients with epilepsy have EEG abnormalities Even though some patients with epilepsy may have normal EEGs due to hidden discharge sites or sparse abnormal discharges or fewer seizures, the value of EEG in the diagnosis of epilepsy is indisputable, and it has become an indispensable test for diagnosis and staging. There are many patients with epilepsy who have very definite epileptic seizures and have had an EEG, but no such epileptiform discharges are seen, so what could be the cause? The EEG is a random signal that changes over time. Even if there is a lesion in the brain, the EEG abnormalities will vary depending on the time and state. In seizure disorders such as epilepsy, most of the paroxysmal abnormalities of the EEG appear randomly, and it is estimated that more than 80% of patients with epilepsy have a definite EEG abnormality. Only 29%-55% of outpatient routine awake EEG recordings can detect epileptiform discharges. Doctors usually have to give the examiner some kind of stimulation to expose the original potential abnormal activity in the brain or enhance the existing abnormal activity, that is, many activation tests and special electrodes have to be placed at the same time during the EEG examination to increase the rate of detecting epileptiform waves, such as Routinely, patients are asked to do visual stimulation situations with eyes open and closed, hyperventilation can induce a catatonic seizure, and there are other evoked tests such as flash stimulation and sleep to increase the detection rate of discharges. Sleep EEG is also important in the diagnosis of epilepsy Although awake EEG is important, sleep EEG is equally important in the diagnosis of epilepsy. There are many patients who have seizures during sleep. Some scholars have found that sleep deprivation can induce seizures, and the EEG after sleep deprivation used by doctors is for this reason. At present, it is common for many hospitals to perform 1-hour awake and 1-hour sleep EEG tracings, which can increase the detection rate of epileptiform discharges to 80%. So without sleep period EEG it can be said that it is incomplete EEG and needs to be especially optimal for natural sleep. However, there are many patients in the hospital examination is difficult to sleep, this can be taken to drug-induced sleep method, commonly used chloral hydrate, the advantage is fast metabolism, but also safer. There are also some patients because of the condition even have to carry out all-night sleep EEG monitoring.