title: Reliability of the adult myopathy assessment tool in individuals with myositis.
abstract: 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 Ho , ρ ≤0.75). All AMAT items had satisfactory intrarater agreement (kappa statistics with Fleiss-Cohen weights, with values κw = 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Veterans Affairs Medical Center and Milken Institute School of Public Health at George Washington University, Washington, DC.
authors.forename: Michael O
authors.initials: MO
authors.lastname: Harris-Love
authors.forename: Galen
authors.initials: G
authors.lastname: Joe
authors.forename: Todd E
authors.initials: TE
authors.lastname: Davenport
authors.forename: Deloris
authors.initials: D
authors.lastname: Koziol
authors.forename: Kristen
authors.initials: K
authors.lastname: Abbett Rose
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Shrader
authors.forename: Olavo M
authors.initials: OM
authors.lastname: Vasconcelos
authors.forename: Beverly
authors.initials: B
authors.lastname: McElroy
authors.forename: Marinos C
authors.initials: MC
authors.lastname: Dalakas
mesh_terms: D000328:Adult; D006801:Humans; D009135:Muscular Diseases / Q000175:diagnosis / Q000503:physiopathology; D009220:Myositis / Q000175:diagnosis* / Q000503:physiopathology*; D059825:Physical Therapists / Q000592:standards*; D010820:Physicians / Q000592:standards*; D015203:Reproducibility of Results