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Reliability of the Adult Myopathy Assessment Tool in Individuals With Myositis
Author(s) -
HarrisLove Michael O.,
Joe Galen,
Davenport Todd E.,
Koziol Deloris,
Abbett Rose Kristen,
Shrader Joseph A.,
Vasconcelos Olavo M.,
McElroy Beverly,
Dalakas Marinos C.
Publication year - 2015
Publication title -
arthritis care and research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.032
H-Index - 163
eISSN - 2151-4658
pISSN - 2151-464X
DOI - 10.1002/acr.22473
Subject(s) - inter rater reliability , medicine , physical therapy , intra rater reliability , confidence interval , reliability (semiconductor) , kappa , standard error , physical medicine and rehabilitation , rating scale , psychology , statistics , philosophy , quantum mechanics , developmental psychology , power (physics) , physics , linguistics , mathematics
Objective The Adult Myopathy Assessment Tool (AMAT) is a 13‐item performance‐based battery developed to assess functional status and muscle endurance. The purpose of this study was to determine the intrarater and interrater reliability of the AMAT in adults with myositis. Methods Nineteen raters (13 physical therapists and 6 physicians) scored videotaped recordings of patients with myositis performing the AMAT for a total of 114 tests and 1,482 item observations per session. Raters rescored the AMAT test and item observations during a followup session (mean ± SD 19 ± 6 days between scoring sessions). All raters completed a single, self‐directed, electronic training module prior to the initial scoring session. Results Intrarater and interrater reliability correlation coefficients were ≥0.94 for the AMAT functional subscale, endurance subscale, and total score (all P < 0.02 for H o , ρ ≤0.75). All AMAT items had satisfactory intrarater agreement (kappa statistics with Fleiss‐Cohen weights, with values κ w = 0.57–1.00). Interrater agreement was acceptable for each AMAT item (κ = 0.56–0.89) except the sit up (κ = 0.16). The standard error of measurement and 95% confidence interval range for the AMAT total scores did not exceed 2 points across all observations (AMAT total score range 0–45). Conclusion The AMAT is a reliable, domain‐specific assessment of functional status and muscle endurance for adult subjects with myositis. Results of this study suggest that physicians and physical therapists may reliably score the AMAT following a single training session. The AMAT functional subscale, endurance subscale, and total score exhibit interrater and intrarater reliability suitable for clinical and research use.