title: Validation of a new objective index to measure spinal mobility: the University of Cordoba Ankylosing Spondylitis Metrology Index (UCOASMI).
abstract: Spinal mobility measures are subject to high variability and subjectivity. Automated motion capture allows an objective and quantitative measure of mobility with high levels of precision. To validate the University of Cordoba Ankylosing Spondylitis Metrology Index (UCOASMI), an index measure of spinal mobility, based on automated motion capture, validation studies included the following: (1) validity, tested by correlation--Pearson's r--between the UCOASMI and the mobility index Bath Ankylosing Spondylitis Metrology Index (BASMI), and a measure of structural damage, the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS); (2) reliability, with internal consistency tested by Cronbach's alpha, test-retest by intraclass correlation coefficient (ICC) after 2 weeks, and error measurement, by variation coefficient (VC) and smallest detectable difference (SDD); and (3) responsiveness, by effect size (ES) in a clinical trial of anti-TNF. Patients for the different studies all had ankylosing spondylitis. Validity studies show correlation between the BASMI (r = 0.881) and the mSASSS (r = 0.780). Reliability studies show an internal consistency of Cronbach's α = 0.894, intra-observer ICC = 0.996, test-retest ICC = 0.996, and a measurement error of VC = 2.80% and SDD = 0.25 points. Responsiveness showed an ES after 24 weeks of treatment of 0.48. In all studies, the UCOASMI's performance was better than that of the BASMI. The UCOASMI is a validated index to measure spinal mobility with better metric properties than previous indices.
authors.affiliation: Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Córdoba, Spain, cc0juanl@uco.es.
authors.forename: Juan L
authors.initials: JL
authors.lastname: Garrido-Castro
authors.forename: Alejandro
authors.initials: A
authors.lastname: Escudero
authors.forename: Rafael
authors.initials: R
authors.lastname: Medina-Carnicer
authors.forename: Alfonso M
authors.initials: AM
authors.lastname: Galisteo
authors.forename: Cristina
authors.initials: C
authors.lastname: Gonzalez-Navas
authors.forename: Loreto
authors.initials: L
authors.lastname: Carmona
authors.forename: Eduardo
authors.initials: E
authors.lastname: Collantes-Estevez
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009038:Motion; D012372:ROC Curve; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013030:Spain; D013131:Spine / Q000503:physiopathology*; D013167:Spondylitis, Ankylosing / Q000175:diagnosis* / Q000503:physiopathology*