Translating the Short-Form Headache Impact Test (HIT-6) in 27 countries: methodological and conceptual issues.

The process of translating the Short-Form Headache Impact Test (HIT-6) in 27 countries and the comparability of the content of the translations is discussed. HIT-6 translations were developed using a standard forward-backward translation process, including a cognitive debriefing step and international harmonization of the translations. Prior to translating the HIT-6, modifications were made to the English-language source form, to improve translation equivalence. In general, the HIT-6 was not difficult to translate. The most difficult items included colloquial expressions such as 'fed up' and words whose intended meaning changed in translation such as 'school' or 'lie down.' Subjects generally found the HIT-6 translations to be clear and relevant. The translation process resulted in questionnaires that are both culturally appropriate and comparable in content.