Translation and validation of the Child and the Adolescent HARDSHIP (Headache-attributed restriction, disability, social handicap and impaired participation) questionnaire into Danish language

Background. The prevalence of headaches among children and adolescents varies considerably between countries. This may be due to a lack of appropriate instruments to capture the prevalence. The purpose of this study was to translate the Child and Adolescent HARDSHIP questionnaires from English into Danish language, conduct cross-cultural adaptation, face validation by cognitive interviewing and conduct a pilot study exploring time requirements. Methods. The questionnaire was translated using the guidelines proposed by "The Global Campaign to Reduce the Burden of Headache." A total of 25 children from 6 to 12 years of age completed the questionnaire with 24 h between test and retest to assess reliability. A total of 169 children and adolescents from 6 to 17 years of age completed the translated questionnaire to assess time requirements for completing it. Results. Only minor discrepancies were observed in the translation process. Test-retest reliability of the translated questionnaire showed substantial agreement (kappa: 0.65-0.78). The questionnaires were completed within 30 min (age 6-11 years of age) and within 15 min (age 12-17 years of age) respectively. Discussion. No major problems were observed in the forward translations of the questionnaires. The face validation prompted no major changes in the questionnaire. The face-to-face interviews showed that pupils of different ethnic backgrounds than Danish and pupils in the age group of 6-11 had more difficulty in understanding a minority of the questions. The Danish Child and Adolescent HARDSHIP questionnaire therefore complies with the intentions of the originators, aiming at a maximal completion time of 45 min and in comparison with actual completion time. The test-retest study showed substantial agreement between test and retest in the headache, migraine and MOH domains and questions referring to time.The Child and Adolescent HARDSHIP questionnaire, includes a section specifically recording a four-week period.The Child and Adolescent HARDSHIP questionnaire is intended to measure burden of headache in large populations and there is therefore no need to reflect the states of individuals. We therefore find the substantial reliability of the Danish version of the Child and Adolescent HARDSHIP questionnaire to be adequate, without supplementing with a diary. The pilot study indicates that headache is a major problem among children and adolescents in Denmark. A total of 95.3% of the pupils have experienced h