Headache syndromes suggested by statistical analysis of headache symptoms.

Statistical study of the correlation between 49 variables concerning characteristics of headache and of headache patients was carried out on 1,198 sequential patients complaining of severe or disabling headaches and attending a headache clinic. Factor analysis was the statistical method employed, 17 factors accounting for 64% of total variation emerged. The most prominent factor contained descriptors of neurological dysfunction associated with headache. Another factor contained variables of nausea and vomiting, only associated with inability to work. Other factors, contained separately, the following variables: (a) Time of headache, (b) time of week of headache, (c) unilateral nature of headache, (d) visual phenomena associated with headache. Relation of these findings to headache taxonomy is discussed.