TY - JOUR
T1 - Rasch-built myotonic dystrophy type 1 activity and participation scale (DM1-Activ)
AU - Hermans, Mieke C. E.
AU - Faber, Catharina G.
AU - De Baets, Marc H.
AU - de Die-Smulders, Christine E. M.
AU - Merkies, Ingemar S. J.
PY - 2010/5
Y1 - 2010/5
N2 - We describe the development of an outcome measure of activity and participation for patients with myotonic dystrophy type 1 using the Rasch measurement model. A 49-item questionnaire was completed by 163 DM1 patients. Data were subsequently analyzed with Rasch software to design the item set to fit model expectations. Through systematic investigation of response category ordering, model fit, item bias, and local response dependency, we succeeded in constructing a 20-item unidimensional scale of activity and participation (DM1-Activ). High internal consistency (PSI = 0.95) and good test-retest reliability values of item difficulty hierarchy and patient location were demonstrated. Patient measures had acceptable correlations with MRC sum scores and MIRS grades (ICC = 0.69 and 0.71, respectively), indicating good external construct validity. DM1-Activ is a practical, reliable and valid outcome measure that fulfils all clinimetric requirements. Further evaluation of this scale is needed to provide a nomogram for clinical use.
AB - We describe the development of an outcome measure of activity and participation for patients with myotonic dystrophy type 1 using the Rasch measurement model. A 49-item questionnaire was completed by 163 DM1 patients. Data were subsequently analyzed with Rasch software to design the item set to fit model expectations. Through systematic investigation of response category ordering, model fit, item bias, and local response dependency, we succeeded in constructing a 20-item unidimensional scale of activity and participation (DM1-Activ). High internal consistency (PSI = 0.95) and good test-retest reliability values of item difficulty hierarchy and patient location were demonstrated. Patient measures had acceptable correlations with MRC sum scores and MIRS grades (ICC = 0.69 and 0.71, respectively), indicating good external construct validity. DM1-Activ is a practical, reliable and valid outcome measure that fulfils all clinimetric requirements. Further evaluation of this scale is needed to provide a nomogram for clinical use.
KW - Myotonic dystrophy type 1
KW - Outcome assessment
KW - Rasch analysis
U2 - 10.1016/j.nmd.2010.03.010
DO - 10.1016/j.nmd.2010.03.010
M3 - Article
C2 - 20363134
SN - 0960-8966
VL - 20
SP - 310
EP - 318
JO - Neuromuscular Disorders
JF - Neuromuscular Disorders
IS - 5
ER -