RESUMO
Prevalence of headache was studied by house-to-house survey of a small remote Mexican village where the population was characterized by a low income and high rate of illiteracy. Severe headache was found in 8.9% of the male population and in 10.6% of the females. Approximately half of these individuals gave a history suggestive of headache with aura, but reinterview by a neurologist revealed that in one third of such histories the visual phenomena were probably not true aurae. Only in the over 35-year age-group was headache more prevalent in females. 'Incapacitating' headache was usually equated with 'severe' headache and was 10 times as frequent in the over 55-year age-group as in younger people. Sophisticated interviewers (neurologists) obtained different results from less trained interviewers.