title: [Evaluation study of the chronic headache questionnaire].
abstract: BACKGROUND
  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.
  
  
  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.
authors.affiliation: Unidad de Cefaleas, Servicio de Neurología, Hospital Clínico Universitario de Zaragoza, España.
authors.forename: E
authors.initials: E
authors.lastname: Muñoz-Farjas
authors.forename: F
authors.initials: F
authors.lastname: Morales
authors.forename: E
authors.initials: E
authors.lastname: Bernal
authors.forename: J
authors.initials: J
authors.lastname: López del Val
mesh_terms: D000328:Adult; D000368:Aged; D002648:Child; D002908:Chronic Disease; D003937:Diagnosis, Differential; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000175:diagnosis*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D018781:Tension-Type Headache / Q000175:diagnosis*
vernacular_title: Estudio de validación de un cuestionario para cefaleas crónicas.