Open AccessAssessment of the validity and reliability of the 32-item Motor Function Measure in individuals with Type 2 or non-ambulant Type 3 spinal muscular atrophy
Author(s) -
Dylan Trundell,
Stephanie Le Scouiller,
Laure Le Goff,
Ksenija Gorni,
Carole Vuillerot
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0238786
Subject(s) - cronbach's alpha , intraclass correlation , sma* , convergent validity , physical medicine and rehabilitation , concurrent validity , spinal muscular atrophy , psychology , physical therapy , medicine , psychometrics , developmental psychology , mathematics , internal consistency , combinatorics
The 32-item Motor Function Measure (MFM32) is an assessment of motor function, and its measurement properties were established in a broad neuromuscular disease population. This study sought to investigate the reliability, validity, and ability to detect change of MFM32 in individuals with Type 2 and non-ambulant Type 3 spinal muscular atrophy (SMA). Data were used from the Phase 2 study assessing the efficacy and safety of olesoxime. A total of 110 individuals with Type 2 or 3 SMA were included in the analyses. Test-retest reliability (intraclass-correlation coefficient in global impression-defined stable individuals), internal consistency (Cronbach’s alpha), convergent validity (Spearman rank order correlations with other measures), known-groups validity (analysis of covariance comparing Hammersmith Functional Motor Scale -defined groups), and ability to detect change (analysis of covariance comparing global impression-defined groups) were calculated. Strong evidence of test-retest reliability (intraclass-correlation coefficient = 0.93–0.95), internal consistency (Cronbach’s alpha = 0.89), convergent validity (Hammersmith Functional Motor Scale: rho = 0.87; forced vital capacity: rho = 0.61), known-groups validity (all p <0.0001), and ability to detect change (all p <0.001) were demonstrated. These results provide evidence of the MFM32’s measurement properties, supporting its use in longitudinal research in individuals with Type 2 and non-ambulant Type 3 SMA.