The relationship between migraine and epilepsy is not adequately clarified so far. The connection was described in several small entities (e.g. migraine-like headache as an epileptic manifestation, epileptic seizures triggered by epileptic attacks, and epilepsies with occipital spike waves), but it appears to be not a fundamental interconnection between both diseases. During visual aura, either slow waves, depression of background activity amplitude or normal EEG have been reported in migraine. The most definitely abnormal EEGs with unilateral or bilateral delta activity have been recorded during attacks of hemiplegic migraine, and during attacks of migraine with disturbed consciousness. Generally, migraine patients do not show typical epileptiform discharges in EEG and the changes that may be detected are usually unspecific and related to accompanying symptoms of migraine like aura or sleepiness.

1. The changes in migraines are RARE because they are only DURING the attack, whereas in seizures there are (often) interictal abnormalities.

2. Interictal abnormalities that are epileptiform (sharp waves, spikes) are specific for seizures and are not seen in migraines.

3. Careful what you read, EEGs are misread (over-interpreted) all the time.

To whom it may concern

The question is unclear. Perhaps you could explain what you mean by TLE,? presumably Temporal Lobe Epilepsy. Next tell us what you mean by SP and CP.

The only proof for the diagnosis epilepsy is the presence of spike wave complexes, which you never find in migraine, but unfortunately mostly also not in TLE. .

Kees Brunia

While I am a statistician and not neurologist, however I agree more or less with Selim Benbadis and Cornelis Brunia. For migraine patients the EEG may shows some degree of abnormalities during a typical migraine attack and off migraine attack it may or may not have significant abnormalities. However the presence of abnormal EEG can be seen in epileptic patients both on and off typical episode of epileptic attack.

Mary Almas

Yes, Kees, I am talking about temporal lobe epilepsy. I referred to simple partial and complex partial szs as SP and CP; I apologize for the confusion.

I appreciate your answers, particularly the comment about overinterpreting EEGs (by Selim Benbadis). I guess I am unsure about the literature stating that--even in the ictal state--some patients with TLE have "normal" (or only mildly abnormal) EEGs, with their seizure focus/foci only later being found with invasive monitoring. So maybe I'm interested in knowing when this type of monitoring would be indicated in a patient with a normal/slightly abnormal EEG and clear symptomology vs saying it's "just migraines" and calling it quits?

Thank you all for your time.

If I understand correctly, one could reword the question as, "Can a seizure disorder manifest with only recurrent headache? Would this be a sufficient indication for invasive EEG monitoring?"

I'd recommend against it if really the only thing that looks wrong about the patient is headache. If there is no alteration of consciousness or any other symptom clinically during the headache that could suggest a seizure, no other neurological problem, no interictal EEG abnormality including after sleep deprivation and during sleep, no morphological brain abnormality... The probability of a seizure disorder seems low. Further, ictal headache is poorly localizing per se, so you would have a hard time knowing where to place the intracranial electrodes.

classical ictal EEG patterns with a pattern of rhythmic activity, often spike or sharp waves evolving in frequency of discharge and spatial extent over time is not typical for migraine during the ictus which may have focal slowing, potentially rhythmic. There may well be some physiological link between the two and some interictal similarities but the ictal EEG patterns are generally different.

Epilepsy and Migraine are crhonic neurologic disorder. Both disorder are characterized by episodes of neurologic dysfunctions : headache, as wel as gastrointestinal, autonomic, and psychology features. This clinical presentation of epilepsy and migraine may overlap , creating a challenger in diferencial diagnosis. So the EEG is extraordinarily useful in diagnosing epilepsy, it is less valuable in diagnosing migraine. EEG recorded during an attack of migraine, are usually normal. Sometime EEG during na attack of migraine occur focal slowing, although this is not a consistent finding. Paroxysmal lateralized epileptiforme discharges (PLEDs) has been associated with hemiplegic migraine, prolonged migraine aura, or incipient migrainous infarction. The EEG abnormalities in migraine should be viewed as exceptions.

From a signal processing point of view you could employ pattern recognition techniques such as Hidden Markov Models to classify the migraine or seizure however the model would need a fair amount of training data which may prove difficult to acquire due to the number of epochs necessary for the technique to be effective, however given the time and the data this can prove to be quite powerful.

Thanks for the clarification CJ. If the patient does not respond to medication, then thy can be admitted to a long term video EEG unit for 3 or more days. The goal of that monitoring is to capture at least a few characteristic seizure events with EEG. If the patient has a normal ictal EEG, then we think if there is other evidence for an EEG negative epilepsy (evidence perhaps from clinical findings, neuropsych, MEG, MRI and/or PET). If the patient is a potential candidate for respective neurosurgery, then intracranial grid or depth electrodes. The scope of the grid and depth cannot cover the whole brain, so you need some hypothesis for the seizure focus before you do it.

Basal EEG is hardly helpful for migraine diagnostics (both aura and headache), while evoked potentials might be of interest. Hence, amplitude of components of cognitive potentials increases in migraine and demonstrates opposite direction of changes in epileptic patients. That is impossible to differentiate with EEG data between two diseases for up to 5% patients suffered from migraine and epilepsy simultaneously.

Thank you all. You've given me a lot to think about...and a lot of directions to follow!

Pierre, yes, you've definitely proposed a much better question for me. And I was asking, primarily, about patients who have headache, alteration of consciousness, amnesia, autonomic responses, etc. This diagnostic conundrum is where the confusion lies.

Some who have responded state that there are definite ictal EEG manifestations, while others note the possibility of EEG-negative epilepsy. This is my concern. Are these beliefs confined to particular demographics [of provider/researcher/etc]? Crazy question but interesting, nonetheless.

Evoked potentials is an interesting way of diagnosing; I'll look into that more. Are there any disorders that mimic "classic migraine" or "classic epilepsy" with EPs?

Again, I appreciate all of your answers.

I think that the differentiation between migraine & epilepsy is more challenging among children than in adults especially in migranous children with atypical migraine aura or with episodic loss of consciousness. Also in first years of life in which the manifestations of migraine are unlear such as head banging in infants as well as vague symptoms in the preschool children. The need for EEG is important in such cases