The Vågå study; epidemiology of headache I: the prevalence of ultrashort paroxysms.

In a large-scale study of headache epidemiology in Vågå, Norway, 1838 adult parishioners(18--65 years of age) were examined, and this represents 88.6% of the target group. Jabs and jolts syndrome/idiopathic stabbing headache (ISH) was verified in 35.2% of the questioned parishioners. This prevalence is much higher than previously observed ones. There were clearly more females than males, the female/male ratio being 1.49, as compared to a ratio of 1.06 in the study cohort (P-value: < 0.0001, chi(2) test). The ratio, 1.49, also differs clearly from a previously observed one: 6.6 (P-value = 0.0003, Fisher's exact test). Control studies included blinded re-check of 100 work-ups, with complete concurrence (kappa-value of 1.00 and blinded re-check of 41 individuals (kapp value of 0.841). Jabs and jolts/ISH are frequent and almost the sole shortlasting (generally < 3 s duration) cephalic paroxysms.