Migraine is surprisingly often mistaken for epilepsy, particularly when the headache is mild or absent , Migrainous aura may have visual, sensory or motor features that may be suggestive of seizure activity, and alertness is sometimes impaired. Postictal headache is also common in epilepsy, and this can make the distinction more complicated than anticipated.
Some unusual types of seizures, particularly those that originate in the occipital lobe, can be difficult to distinguish from migraines because features such as visual disturbance occur in both disorders [49,50], Since there is no diagnostic test for migraine, the diagnosis is clinical. Migraines are more common amongst those who suffer syncope and there is often some overlap with the symptoms. Although visual disturbances are the most common neurological feature of migraine, sensory or motor change, speech disturbance, amnesia or confusion and even loss of consciousness may occur.
Migraine may have specific triggers such as foods, medication, emotional stress or visual stimuli. Sensory or visual symptoms generally build up slowly and typically spread over minutes, progressing stepwise from one affected cortical region to the next, with resolution of the symptoms as a new area is involved. Typical symptom duration is 15-30 min though occasionally episodes last longer and may not be followed by headache.
Whereas epilepsy and migraine are both common, one might anticipate encountering them occasionally in the same patient. This has been studied by a number of authors  with differing results. There seems to be no excess of epilepsy amongst patients with migraine overall . None the less the distinction of migraines from seizures can be difficult. Some authors have postulated that migraines might be a seizure equivalent , In some patients migraines trigger seizures , but this is rare.
Postictal migraine is well recognized and may have some lateral-izing value [52,55]. Seen in focal and generalized syndromes, it more often occurs after a tonic-clonic convulsion. The increased cerebral blood flow that is induced by seizure activity is felt to be responsible for this headache. Often these types of headaches occur in patients who suffer migraines at other times. However, the patient who presents with new onset headache and seizure obviously requires the exclusion of an acute neurological problem such as intracranial haemorrhage or infection.
Seizures of occipital origin have many features of migraine, with visual hallucinations or amaurosis often complicated by headache. Benign partial epilepsy with occipital paroxysms is a syndrome of childhood to teenage years [56,57], Hallucinations are typically simple in nature but can be complex and followed by complex partial or generalized convulsions  after which come the headache with nausea and vomiting. The diagnosis depends on observing the distinctive interictal EEG pattern. Occipital seizures resulting from structural pathologies, such as coeliac disease and mitochondrial encephalomyelopathies, may share these features ,
Non-specific EEG changes occur with migraine, but specific epileptiform abnormalities are rare , Finding interictal spikes in patients with migraine suggest an alternative diagnosis, such as benign occipital epilepsy in children or the possibility of a structural lesion in adults. As a rule, EEG is not useful in typical migraine. Minor abnormalities seen during episodes need to be interpreted with great caution.
The diagnosis of migraine is clinical and rests on recognizing the typical progression of symptoms, the duration of attack (tens of minutes rather than seconds), and gradual resolution. Response to anticonvulsant therapy is an unreliable basis for making the diagnosis.
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