Epilepsy has been linked to migraine headaches. They are comorbid conditions, which means if you have one of them, there is a greater likelihood of having the other. In most cases, however, it is a matter of a patient with two different neurologic conditions with occasional overlapping of symptoms. Patients with epilepsy may at times have a "postictal" or "post-seizure" headache. This headache is diffuse, throbbing, and moderate and subsides over a number of hours.
The diagnosis of epilepsy or seizure disorder is partially based on the results of electroencephalography (EEG). EEGs may also be ordered in the workup of migraine patients, particularly in children with headaches or those patients experiencing basilar artery migraine. Occasionally, mild abnormalities in the brain wave patterns may be observed on EEG. These changes are not characteristic of epilepsy.
Antiepileptic drugs, such as phenobarbital and phenytoin, have been used previously as agents in migraine treatment. However, these medications were not effective in reducing migraine attacks. In the past 15 years there has been substantial evidence that some antiepileptic agents, most notably, valproic acid, topiramate are useful in the prevention of migraine. These medications may effect brain chemistry and preventing the propagation of a wave referred to as "cortical spreading depression" in migraine. When discontinuing these agents, it is important to do this slowly, to avoid the change of inducing seizures.