Assessment 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

PLoS One. 2020 Sep 18;15(9):e0238786. doi: 10.1371/journal.pone.0238786. eCollection 2020.

Abstract

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.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Child, Preschool
  • Cholestenones* / adverse effects
  • Cholestenones* / pharmacology
  • Female
  • Humans
  • Longitudinal Studies
  • Male
  • Motor Activity
  • Psychomotor Performance
  • Retrospective Studies
  • Severity of Illness Index
  • Spinal Muscular Atrophies of Childhood* / drug therapy
  • Spinal Muscular Atrophies of Childhood* / physiopathology
  • Young Adult

Substances

  • Cholestenones
  • olesoxime

Grants and funding

This study is sponsored by F. Hoffmann-La Roche Ltd. The funder provided support in the form of salaries for authors [DT, KG and SS], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section. Writing and editorial assistance was provided by Megan Allen, PhD, of MediTech Media, UK (funded by F. Hoffmann-La Roche Ltd) in accordance with Good Publication Practice (GPP3) guidelines (http://www.ismpp.org/gpp3).”