Development of a new questionnaire to assess pain‐related limitations of daily functions in Japanese patients with temporomandibular disorders

Abstract

Various measures/scales have been used to assess oral health-related quality of life in patients with temporomandibular disorders (TMDs). However, there have been few reports on the validity of questionnaires, and even fewer assessments of their use in Japanese sociocultural conditions. The objectives of the study were: (i) to develop and refine the number of questions concerning pain-related limitations of daily function in the TMD questionnaire (LDF-TMDQ, 13 items) in Japanese patients with TMD, (ii) to assess factor validity, and (iii) to determine convergent and discriminant validity of the LDF-TMDQ with the observed items within a multidimensional questionnaire. Four hundred and fifty-six (85.9%) outpatients with TMD were enrolled. The subjects were allocated into two roughly equal groups--E-group (233) for exploratory factor analysis and C-group (223) for confirmatory factor analysis [structural equation modeling (SEM)]. The exploratory factor analysis extracted 10 items and three factors. SEM showed the revised model to accurately describe the relationships between the measured items. As to convergent validity, the factor 'limitation in executing a certain task' and 'limitation of mouth opening' showed significant correlations with the observed items within the multi-dimensional questionnaire. However, the factor 'limitation of sleeping', show no correlation with any item. As to discriminant validity, all three factors had correlation coefficients below 0.4 with the psychological scale, the personality scale, and the visual analog scale for pain intensity. The LDF-TMDQ was reduced from 13 items to 10. The factor validity of the LDF-TMDQ, and the construct validity of 'limitation in executing a certain task' and 'limitation of mouth opening' were confirmed, while that of 'limitation of sleeping' remains to be determined.