Validation of the Japanese Society for Surgery of the Hand version of the Disability of the Arm, Shoulder, and Hand questionnaire

BACKGROUND The Disability of the Arm, Shoulder and Hand (DASH) questionnaire is a region-specific self-administered questionnaire that consists of a disability/symptom (DASH-DS) scale, and two optional modules, the work (DASH-W) and the sport/music (DASH-SM) modules. The DASH was cross-culturally adapted and developed by the Impairment Evaluation Committee, Japanese Society for Surgery of the Hand. The purpose of this study was to test the reliability, validity, and responsiveness of the Japanese version of DASH (DASH-JSSH). METHODS A series of 72 patients with upper extremity disorders completed the DASH-JSSH, the medical outcomes study 36-item short-form health survey (SF-36), and the Visual Analog Scale (VAS) for pain. Thirty-eight of the patients were reassessed for test-retest reliability 1 or 2 weeks later. Reliability was investigated by reproducibility and internal consistency. To analyze the validity, a principal component analysis and correlation coefficients between the DASH-JSSH and the SF-36 were obtained. Responsiveness was examined by calculating the standardized response mean (mean change/SD) and effect size (mean change/SD of baseline value) after carpal tunnel release of the 17 patients with carpal tunnel syndrome. RESULTS Cronbach's alpha coefficients in the DASH-DS and DASH-W were 0.962 and 0.967, respectively. The intraclass correlation coefficients for the same were 0.82 and 0.85, respectively. The unidimensionality of the DASH-DS and DASH-W were confirmed. The correlations between the DASH-DS score and the subscale of the SF-36 scale ranged from -0.29 to -0.73. The correlation coefficient between the DASH-DS and the DASH-W was 0.79. The standardized response mean/effect size of DASH-DS, DASH-W, and VAS for pain were -0.48/-0.26, -0.68/-0.41, and -0.40/-0.40, respectively. DASH-DS and DASH-W were as moderately sensitive as VAS for pain. CONCLUSION The DASH-DS and DASH-W Japanese version have evaluation capacities equivalent to those of the original and other language versions of the DASH.