The neurologist looks for spikes or sharp waves ('epilepsy waves') to confirm the diagnosis, but the absence of these abnormal brain waves does not mean you didn't have a seizure in the past. These waves may or may not show evidence of seizure activity. The EEG generally records brain waves between seizures, called interictal brain waves. The likelihood of recording a seizure during a routine EEG is small.When an EEG is done several hours or even days later, it misses the changes in electrical activity that occurred during the actual seizure. Once the seizure is over, the brain rapidly returns to normal in most individuals. During a seizure, the electrical activity is abnormal.If you aren't having a seizure at that time, there may not be any unusual brain waves for the test to record. This is because the EEG only shows brain activity during the time of the test. Even someone who has seizures every week can have a normal EEG test. Approximately one-half of all EEGs done for patients with seizures are interpreted as normal. A normal EEG does not mean that you did not have a seizure.Does a normal EEG mean that you didn’t have a seizure and the headache and muscle aches you felt were related to some other illness? The neurologist has just informed you that your EEG is normal even though you recently experienced your first tonic-clonic seizure.

Abnormal eeg normal vs epilepsy