Study to validate a questionnaire for chronic headache
Introduction. Semi-structured questionnaires, based on clinical criteria are used in the diagnosis of headache, but none has been used to study the two commonest types of chronic headache. The first step, before clinical application, is to carry out a study of the questionnaire's validity and predictive value. Objective. The objectives of our study were to evaluate the validity and determine the effectiveness of the ZZA questionnaire in the differential diagnosis between transformed migraine (TM) and chronic tension headache (CTH), in a specialist Neurology Clinic. Material and methods. The ZZA questionnaire, elaborated by one of the investigators, was made up of 20 questions aimed at TM, CTH or the chronicity of the headache. An observer, who did not know the diagnosis, gave the questionnaire to patients who had previously been diagnosed by the head of the Headache Clinic as having TM or CTH. The process of validation of the questionnaire consisted in showing that it was reliable, with valid contents and valid criteria. Results. On analysis of reliability, the items ZZA1, ZZA15, ZZA16 and ZZA18 gave the highest indices. The Cochran Q test showed lack of uniformity of replies. Only ZZA1, ZZA15 and ZZA18 were predictive items showing MT. None of the questions to show CTH were predictive. After final adjustment the definitive model was made up of ZZA1, ZZA15 and ZZA18. Conclusions. The proposed questionnaire was not found to be useful for differential diagnosis between TM and CTH. Only 3 of the 20 questions were accepted as having some degree of validity and effectiveness. Two of these 3 questions, based on clinical impressions of the author, might well be included in the diagnostic criteria of TM
Objetivo Los objetivos de nuestro trabajo fueron evaluar la validez y determinar la efectividad del cuestionario ZZA en el diagnóstico diferencial entre migraña trasformada (MT) y cefalea tensional crónica (CTC), en la consulta especializada de Neurología. Material y métodos. El cuestionario ZZA, elaborado por uno de los investigadores, constaba de 20 preguntas dirigidas hacia la MT, la CTC o la cronicidad de la cefalea. Un observador, no conocedor del diagnóstico, aplicó el cuestionario a pacientes previamente diagnosticados por el responsable de la consulta de cefaleas, de MT o CTC. El proceso de validación del cuestionario consistió en demostrar que tenía fiabilidad, validez de contenido y validez de criterio.
Resultados En el análisis de la fiabilidad, los índices más elevados correspondieron a los ítems ZZA1, ZZA15, ZZA16 y ZZA18. La prueba Q de Cochran evidenció ausencia de homogeneidad en las respuestas. De los ítems discriminatorios para MT, los que resultaron predictivos fueron ZZA1, ZZA15 y ZZA18; ninguno de los ítems discriminatorios para CTC resultó predictivo. El ajuste final realizado permitió obtener un modelo definitivo formado por ZZA1, ZZA15 y ZZA18.
Conclusiones El cuestionario propuesto no resultó útil para el diagnóstico diferencial entre MT y CTC. Entre las 20 preguntas, sólo en tres se aceptaba que tenían cierto grado de validez y efectividad. Dos de estos 3 ítems, basados en apreciaciones clínicas del autor, bien podrían incluirse entre los criterios diagnósticos de MT
