Can tests confirm that a seizure occurred?
People often assume that tests such as an EEG, a CT scan or an MRI will tell if they have had a seizure. However, information from tests alone cannot confirm that a seizure has occurred. The doctor relies heavily on information from the patient and witnesses to make a diagnosis. The EEG test records the electrical activity of the brain. However, electrical changes can often be seen only during a seizure, so a normal EEG, taken when a seizure is not occurring, doesn’t mean that a seizure has not occurred at some other time. An abnormal EEG can suggest that the person is more likely to have seizures, and this can be helpful to the doctor. However, an EEG can be abnormal for many reasons. CT and MRI scans show how the brain is built and, occasionally, a possible cause for seizures can be seen on a scan. However, like an EEG, the scans can be normal in people who have seizures, and not everything unusual on a scan will be a cause of seizures. In some people, the EEG and CT or MRI scans are
