Familial migraine with and without aura: clinical characteristics and co-occurrence.

Migraine with aura (MwA) and migraine without aura (MwoA) are the two common forms of migraine. Many migraine patients suffer from both kinds of attacks. In a questionnaire-based study using the current International Headache Society (IHS) criteria we determined the clinical characteristics and occurrence of MwA + MwoA in 1000 migraine patients belonging to 210 Finnish migraine families. Nine hundred and six patients were able to indicate whether they suffered from MwA (but not MwoA), migraine aura without headache (migraine equivalent) (but not MwA) or MwA and MwoA. Of these patients, 3.2% had experienced MwoA, 11.1% MwA, 40.6% MwA + MwoA, 23.5% MwoA and 20.3% MwA-like symptoms not meeting the IHS criteria. The high prevalence of MwA attacks in the families studied supports the belief that aura has a strong hereditary component. The MwA + MwoA patients had significantly more severe attacks, more typical headache and more prodromal symptoms than the MwA and MwoA subjects. Therefore, it is possible that there is a continuum with pure MwA at the neural and pure MwoA at the headache end of the spectrum, and MwA + MwoA lying in between the two. The MwA + MwoA patients would thus be liable to both types of migraine, making their attacks more characteristic and more severe. This would also explain why the co-occurrence of MwA and MwoA is more common in the clinic compared with population based epidemiological studies. These findings have consequences for future research on liability genes for migraine.