Childhood headaches: discrete entities or continuum?

The aims of this study were to investigate the signs and symptoms of recurrent headaches in children and to identify if there are any discrete groups of children whose headaches corresponded to the World Federation of Neurology (1969) definition of migraine. One-hundred and fifty children recruited from the neurology clinics at Royal Manchester, Booth Hall, and Birmingham Children's Hospitals were interviewed to complete a standardized questionnaire. The data were examined using cluster analysis followed by comparative analysis of the headache signs and symptoms in the different groups identified. No stable groups were identified (i.e., no group was reliably identified by different methods of cluster analysis) which corresponded to the World Federation of Neurology definition of migraine. This would suggest that this definition is not appropriate for the sample investigated. Three groups of children evolved after cluster analysis. None of these groups was in agreement with the International Headache Society classification of headaches. The groups were neither 'stable' clusters nor 'useful' in predicting prognosis. This outcome supports the continuum theory of headache syndromes.