Headache in patients with epilepsy: a prospective incidence study.

High prevalence of headache has been reported in patients with refractory epilepsy in cross-sectional surveys based on retrospective recall. We conducted a prospective study to document the incidence of headache over a 3-month observation period in a cohort of 227 adult patients with less refractory epilepsy. The mean seizure frequency was 2.46 per month. Fifty (22%) patients reported to have had at least one headache episode, 45 (19.8%) had interictal headache, 11 (4.8%) had periictal headache, and 5 (2.2%) had both interictal and periictal headache. Forty-nine percent of the patients with headache took over-the-counter analgesics as acute treatment. The headache was rated to have made very severe or substantial impact on their lives by 34% of patients. A formal headache diagnosis was not made in any of the patients prior to the survey. Although the incidence of headache in epilepsy patients appeared to be low, it was underdiagnosed and associated with substantial negative impact.