Validation of manual muscle testing and a subset of eight muscles for adult and juvenile idiopathic inflammatory myopathies
Article first published online: 30 MAR 2010
Copyright © 2010 by the American College of Rheumatology
Arthritis Care & Research
Volume 62, Issue 4, pages 465–472, April 2010
How to Cite
Rider, L. G., Koziol, D., Giannini, E. H., Jain, M. S., Smith, M. R., Whitney-Mahoney, K., Feldman, B. M., Wright, S. J., Lindsley, C. B., Pachman, L. M., Villalba, M. L., Lovell, D. J., Bowyer, S. L., Plotz, P. H., Miller, F. W. and Hicks, J. E. (2010), Validation of manual muscle testing and a subset of eight muscles for adult and juvenile idiopathic inflammatory myopathies. Arthritis Care Res, 62: 465–472. doi: 10.1002/acr.20035
- Issue published online: 30 MAR 2010
- Article first published online: 30 MAR 2010
- Manuscript Accepted: 20 NOV 2009
- Manuscript Received: 10 AUG 2009
- Intramural Research Program of the NIH
- National Institute of Environmental Health Sciences
- National Institute of Arthritis and Musculoskeletal and Skin Diseases
- Rehabilitation Medicine Department
- NIH Clinical Center
- Canada Research Chair in Childhood Arthritis
To validate manual muscle testing (MMT) for strength assessment in juvenile and adult dermatomyositis (DM) and polymyositis (PM).
Patients with PM/DM (73 children and 45 adults) were assessed at baseline and reevaluated 6–9 months later. We compared Total MMT (a group of 24 proximal, distal, and axial muscles) and Proximal MMT (7 proximal muscle groups) tested bilaterally on a 0–10 scale with 144 subsets of 6 and 96 subsets of 8 muscle groups tested unilaterally. Expert consensus was used to rank the best abbreviated MMT subsets for face validity and ease of assessment.
The Total, Proximal, and best MMT subsets had excellent internal reliability (Total MMT rs = 0.91–0.98), and consistency (Cronbach's α = 0.78–0.97). Inter- and intrarater reliability were acceptable (Kendall's W 0.68–0.76, rs = 0.84–0.95). MMT subset scores correlated highly with Total and Proximal MMT scores and with the Childhood Myositis Assessment Scale, and correlated moderately with physician global activity, functional disability, magnetic resonance imaging, and axial and distal MMT scores, and, in adults, with creatine kinase level. The standardized response mean for Total MMT was 0.56 in juveniles and 0.75 in adults. Consensus was reached to use a subset of 8 muscles (neck flexors, deltoids, biceps, wrist extensors, gluteus maximus and medius, quadriceps, and ankle dorsiflexors) that performed as well as the Total and Proximal MMT, and had good face validity and ease of assessment.
These findings aid in standardizing the use of MMT for assessing strength as an outcome measure for myositis.