A New Functional Scale and Ambulatory Functional Classification of Duchenne Muscular Dystrophy: Scale Development and Preliminary Analyses of Reliability and Validity

OBJECTIVE: To develop a simplified functional scale and classification system to evaluate the functional abilities of patients with Duchenne muscular dystrophy (DMD). METHODS: A Comprehensive Functional Scale for DMD (CFSD) was developed using the modified Delphi method. The accompanying Ambulatory Functional Classification System for DMD (AFCSD) was developed based on previously published classification systems. RESULTS: The CFSD consists of 21 items and 78 sub-items, assessing body structure and function, activities, and participation. Inter-rater intraclass correlation coefficient values were above 0.7 for 17 items. The overall limits of agreement between the two examiners ranged from -6.21 to 3.11. The Spearman correlation coefficient between the total score on the AFCSD and the Vignos Functional Scale was 0.833, and 0.714 between the total score of the AFCSD and the Brooke scale. Significant negative correlations existed between the total score for each functional level of the AFCSD and each functional grade of the Vignos and Brooke scales. The total scores of the CFSD varied significantly between the functional grades of the Vignos scale, and specific grades of the Brooke scale. For the AFCSD, total scores of the CFSD varied significantly between the functional levels. CONCLUSION: We have developed a new scale and the associated classification system, to assess the functional ability of children diagnosed with DMD. Preliminary evaluation of the psychometric properties of the functional scale and classification systems indicate sufficient reliability and concurrent validity.

Translation and Validation of the Korean Version of the International Knee Documentation Committee Subjective Knee Form

PURPOSE: To perform a cross-cultural adaptation and to test the measurement properties of the Korean version of International Knee Documentation Committee (K-IKDC) Subjective Knee Form. MATERIALS AND METHODS: According to the guidelines for cross-cultural adaptation, translation and backward translation of the English version of the IKDC Subjective Knee Form were performed. After translation into the Korean version, 150 patients who had knee-related problems were asked to complete the K-IKDC, Lysholm score, and Short Form-36 (SF-36). Of these patients, 126 were retested 2 weeks later to evaluate test-retest reliability, and 104 were recruited 3 months later to evaluate responsiveness. Construct validity was analyzed by investigating the correlation with Lysholm score and SF-36; content validity was also evaluated. Standardized mean response was calculated for evaluating responsiveness. RESULTS: The test-retest reliability proved excellent with a high value for the intraclass correlation coefficient (r=0.94). The internal consistency was strong (Cronbach's alpha=0.91). Good content validity with absence of floor not ceiling effects and good convergent and divergent validity were observed. Moderate responsiveness was shown (standardized mean response=0.689). CONCLUSIONS: The K-IKDC demonstrated good measurement properties. We suggest that this instrument is an excellent evaluation instrument that can be used for Korean patients with knee-related injuries.