Development and validation of the EUROLIGHT questionnaire to evaluate the burden of primary headache disorders in Europe.

We developed a 103-item self-reporting questionnaire to assess the burden of primary headache disorders on those affected by them, including headache characteristics, associated disability, co-morbidities, disease-management and quality of life. We validated the questionnaire in five languages with 426 participants (131 in UK, 60 in Italy, 107 in Spain, 83 in Germany/Austria, and 45 in France). After a linguistic and a face-content validation, we tested the questionnaire for comprehensibility, internal consistency and test-retest reliability at an interval of one month. In the different countries, response rates were between 73% and 100%. Test-retest reliability varied between -0.27 to 1.0 depending of the nature of the expected agreement. The internal consistency was between 0.69 and 0.91. The EUROLIGHT questionnaire is suitable for evaluating the burden of primary headache disorders, and can be used in English, German, French, Italian and Spanish.