What tests are required to diagnose epilepsy? An EEG is usually required to diagnose epilepsy. The presence of typical epileptiform discharges on the EEG is the main basis for the diagnosis of epilepsy. MRI is also required to determine the presence of structural brain abnormalities and epileptogenic lesions such as tumors, cerebrovascular disease, and parasites. In rare cases, genetic, chromosomal and metabolic genetic tests are required. What is an electroencephalogram? The human brain cells have normal bioelectrical activity. When there is a disease in the brain, the normal electrical activity will change. The EEG is a specific graph that is recorded by an EEG machine that amplifies the brain’s electrical activity. By observing and analyzing the changes in the EEG, the doctor can diagnose the patient’s brain pathology. In epilepsy, the electrical activity of the brain has its own special characteristics, and it is necessary to perform an EEG. Can an EEG without abnormalities rule out epilepsy? A negative EEG does not rule out epilepsy because many patients have a normal EEG when they are not having a seizure. And if the EEG is normal during a seizure, epilepsy can be ruled out. What is an ambulatory EEG? Dynamic EEG is relative to normal EEG. The EEG is recorded for a longer period of time ranging from a few hours to several days, and can record more EEG information, which is more informative for epilepsy diagnosis and prognosis. What is a video EEG? Why is video EEG better than regular EEG? Video EEG is the recording of EEG along with the video data of the patient. It is mainly used to observe the clinical performance during seizures and to study the relationship between electrophysiology and clinical performance. In the absence of seizures, video EEG can better exclude the bit difference during EEG recording. What is the role of MRI for patients with epilepsy? For patients with epilepsy, the main purpose of MRI is to look for the cause of epilepsy. Causes such as traumatic brain injury, cerebrovascular disease, brain tumors, brain parasitism, and abnormal brain development need to rely on MRI for clarification. For focal cortical dysplasia, a previously poorly understood cause, MRI high-resolution thin-layer scans can often provide a definitive diagnosis. Is PET-CT examination accurate? PET-CT is an examination that reflects the metabolic aspects of the brain and has a very high positive diagnostic rate for the seizure phase, but it is difficult to capture PET-CT during the seizure phase. What is generally examined is the brain metabolism in the interictal period, and epileptic lesions usually show low metabolism in the interictal period, so PET-CT has some reference value for the localization of epileptic lesions. However, the results of PET-CT must be evaluated objectively. Not all hypometabolic areas are epileptogenic foci, and not all epileptogenic foci are hypometabolic manifestations. What is the significance of the use of intracranial electrodes in epilepsy surgery? Cortical and deep electrodes are routinely used to detect EEG in epilepsy surgery. Since the EEG signal is relatively weak, and the signal is even weaker after attenuation by the skull and scalp, and the accuracy of the discharge site is compromised. Intracranial electrodes in surgery can directly detect the discharge in the cerebral cortex, and the accuracy of localization is greatly improved. The intracranial electrodes can be used to record the EEG during seizures, which is even more significant for the precise localization of epilepsy.