Different approximations of the McGill Pain Questionnaire in the Norwegian language: a discussion of content validity

The McGill Pain Questionnaire (MPQ) is a well recognized measuring instrument for pain in English-speaking countries. Several efforts have been made to develop equivalent pain-measuring instruments in other languages. However, the method of translating the English words contained in the MPQ into another language implies that questions about validity may be posed. In Norway three different pain questionnaires have been developed which are inspired by the MPQ. A primary focus for developing the Norwegian Pain Questionnaire (NPQ) was the semantics of pain; the focus of the adapted MPQ was to include commonly used somatosensory Norwegian descriptors of pain in the population of patients with low back pain; the Norwegian McGill Pain Questionnaire (NMPQ) was literally translated into Norwegian to provide a equivalent pain questionnaire to the MPQ for cross-cultural comparisons of pain. Examination of content validity of the adapted MPQ and the translated version of the MPQ is examined by comparing the words in those questionnaires with words collected among Norwegians in the process of developing the NPQ. The findings support the content validity of the adapted MPQ. The NMPQ, however, should be further refined to better fit the semantics of pain in Norway.