Clinical characteristics of patients with comorbidity of migraine and epilepsy.

OBJECTIVE: Neuronal hyperexcitability might explain the comorbidity of migraine and epilepsy. Spreading depression, a postulated pathophysiological mechanism of epileptic seizures and migraine with aura, may hypothetically be the link between the disorders in these comorbid conditions. The aim of the present study was to determine whether certain clinical characteristics associated with spreading depression are overrepresented in patients with comorbidity.
METHODS: In an outpatient clinic-based series, clinical characteristics of 61 patients with a comorbidity of migraine and epilepsy were compared to those of 280 patients with epilepsy alone and 248 patients with migraine alone. Patients were interviewed with a standardized questionnaire.
RESULTS: The proportion of females was significantly higher in patients with comorbidity and patients with migraine as compared to patients with epilepsy (P <.001). Comparing patients with epilepsy and comorbidity, the frequency of epilepsy syndromes and seizure types was not significantly different. Comparing patients with migraine and comorbidity, migraine with aura was significantly more frequent in patients with comorbidity (P =.019). Other migraine features such as moderate to severe pain intensity, worsening of pain on activity, phonophobia, and photophobia were significantly more frequent in patients with comorbidity as compared to patients with migraine (P < or =.001).
CONCLUSION: No specific epileptic characteristics could be found in patients with comorbidity. Altered cerebral excitability resulting in an increased occurrence of spreading depression may explain the differences in migraine attacks in patients with comorbidity as compared to patients with migraine alone.