LINGUISTIC VALIDATION OF THE NEUROGENIC BOWEL DYSFUNCTION SCORE IN JAPANESE

OBJECTIVES: The Neurogenic Bowel Dysfunction score (NBD score) is a self-reported symptom-based score for neurogenic bowel dysfunction that takes into account both constipation and fecal incontinence, and weighs each symptom of NBD according to its impact on self- reported quality of life (QoL). It is used for the clinical assessment of colorectal and anal dysfunction in persons with spinal cord injury (SCI). Our objective was to perform a cultural adaption/linguistic validation of the questionnaire into Japanese for use in Japan by following FDA PRO Guidance- and ISPOR-compliant methodology. METHODS: The NBD Score was translated into Japanese utilizing the following process: two forward translations, reconciliation of the forward translations, back translation, and resolution of the back translation with the forward translation. The project team reviewed the translated version before the instrument was evaluated in cognitive interviews (CIs) with a sample of five Japanese individuals with neurogenic bowel dysfunction. RESULTS: Conceptual issues related to the English source text were identified by the Sponsor during review of the final, validated translation. For example, the first item does not include "once a week" as a response option. While this was noted by the respondents during cognitive interviewing, it did not impact their comprehension of the question or the instrument. Any update to the Japanese translation to include this response choice would require an amendment to the original English text. CONCLUSIONS: Through the rigorous translation/adaptation and review process, as well as verification through cognitive interviews, the translation of the NBD score questionnaire into Japanese is considered to be conceptually equivalent and culturally appropriate for the target population. The Japanese version is now linguistically validated for use in clinical trials.