Evaluation of the psychometric properties and the clinical feasibility of a Chinese version of the Dolopus-2 scale among cognitively impaired older people with communication difficulty

Background: Several behaviourally observed tools have been developed to assess pain among cognitively impaired older people with communication difficulty. However, no adequate pain observation instrument is available for this group in Taiwan. Objective: The study was undertaken to translate the French version of the Doloplus-2 scale into Chinese and to evaluate the psychometric properties and the clinical feasibility of the translated instrument. Design: A prospective, descriptive design was used. Settings: Five dementia special care units in the Northern Taiwan were used. Participants: Two hundred and forty-one residents with dementia and 14 registered nurses in charge of these residents were recruited. Methods: The Doloplus-2 scale was translated into Chinese using the back-translation technique and pilot testing was performed to determine the comprehensibility and the initial psychometric characteristics. Internal consistency and inter-rater reliability were evaluated by Cronbach's alpha and intra-class correlation coefficient, respectively. Based on the known correlated validity model, the association between C-Doloplus-2 and empirically supported correlates of pain such as the past pain history, the presence of pain related condition, functional disability, agitation and depression were examined using Pearson's correlation coefficient for validating the construct validity. Furthermore, factor structure was investigated using Principal Components Analysis. Results: The internal consistency was adequate for the total scale (alpha 0.74) and the subscales (alpha range 0.67-0.87). The intra-class correlation coefficient of the total scale was 0.81 and of the subscales ranged from 0.60 to 0.81. The association between pain latent variable and disability or depression was demonstrated, partially supporting the construct validity. Three factors were extracted to confirm the original three-dimensional structure perfectly, accounting 65% of the total variance. Conclusions: The psychometric qualities of Chinese Doloplus-2 were supported. Further research is needed to assess the clinical value of the translated scale performed in the institutions.