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Rasch analysis of clinical outcome measures in spinal muscular atrophy
Author(s) -
Cano Stefan J.,
Mayhew Anna,
Glanzman Allan M.,
Krosschell Kristin J.,
Swoboda Kathryn J.,
Main Marion,
Steffensen Birgit F.,
Bérard Carole,
Girardot Françoise,
Payan Christine A.M.,
Mercuri Eugenio,
Mazzone Elena,
Elsheikh Bakri,
Florence Julaine,
Hynan Linda S.,
Iannaccone Susan T.,
Nelson Leslie L.,
Pandya Shree,
Rose Michael,
Scott Charles,
Sadjadi Reza,
Yore Mackensie A.,
Joyce Cynthia,
Kissel John T.
Publication year - 2014
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.23937
Subject(s) - rasch model , sma* , spinal muscular atrophy , rating scale , physical medicine and rehabilitation , psychology , scale (ratio) , physical therapy , reliability (semiconductor) , medicine , developmental psychology , computer science , quantum mechanics , power (physics) , physics , algorithm
: Trial design for SMA depends on meaningful rating scales to assess outcomes. In this study Rasch methodology was applied to 9 motor scales in spinal muscular atrophy (SMA). Methods : Data from all 3 SMA types were provided by research groups for 9 commonly used scales. Rasch methodology assessed the ordering of response option thresholds, tests of fit, spread of item locations, residual correlations, and person separation index. Results : Each scale had good reliability. However, several issues impacting scale validity were identified, including the extent that items defined clinically meaningful constructs and how well each scale measured performance across the SMA spectrum. Conclusions : The sensitivity and potential utility of each SMA scale as outcome measures for trials could be improved by establishing clear definitions of what is measured, reconsidering items that misfit and items whose response categories have reversed thresholds, and adding new items at the extremes of scale ranges. Muscle Nerve 49 :422–430, 2014