title: Responsiveness of the motor function measure in patients with spinal muscular atrophy.
abstract: OBJECTIVE
  To assess the ability of the Motor Function Measure (MFM) to detect changes in the progression of spinal muscular atrophy (SMA).
  
  
  METHODS
  Observational, retrospective, multicenter cohort study.
  
  
  METHODS
  Seventeen departments of pediatric physical medicine.
  
  
  METHODS
  Volunteer patients with SMA (N=112) aged 5.7 to 59 years with no treatment other than physical therapy and nutritional or respiratory assistance.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  The distributions of the MFM scores (total score and 3 subscores) were analyzed per SMA subtype. The relationships between scores and age were studied. The slopes of score changes (reflecting MFM responsiveness) were estimated in patients with at least 6 months' follow-up and 2 MFMs. Hypothetical sample sizes for specific effect sizes in clinical trial scenarios are given.
  
  
  RESULTS
  In 12 patients with SMA type 2 and 19 with SMA type 3 (mean ± SD follow-up, 25.8 ± 19mo), there was a moderate inverse relationship between age and the MFM total score. Patients with less than 6 months' follow-up showed little score changes. Patients with longer follow-ups showed a slow deterioration (-0.9 points/y for type 2 and -0.6 points/y for type 3). Substantial responsiveness was obtained with the MFM Dimension 2 subscore (proximal and axial motricity) in patients with SMA type 2 (standardized response mean [SRM]=1.29), and with the MFM Dimension 1 subscore (standing and transfers) in patients with SMA type 3 aged 10 to 15 years (SRM=.94).
  
  
  CONCLUSIONS
  If further confirmed by larger studies, these preliminary results on the relative responsiveness of the MFM in SMA will foster its use in monitoring disease progression in patients who participate in clinical trials.
authors: Hospices Civils de Lyon, Hôpital Femme-Mère-Enfant, L'Escale, Service de Médecine Physique et de Réadaptation Pédiatrique, Bron, France. carole.vuillerot@chu-lyon.fr
authors: Carole
authors: C
authors: Vuillerot
authors: Christine
authors: C
authors: Payan
authors: Jean
authors: J
authors: Iwaz
authors: René
authors: R
authors: Ecochard
authors: Carole
authors: C
authors: Bérard
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009134:Muscular Atrophy, Spinal / Q000150:complications / Q000503:physiopathology* / Q000534:rehabilitation; D017063:Outcome Assessment, Health Care; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013647:Task Performance and Analysis; D055815:Young Adult
keywords: Clinical trial; ExpHFMS; Expanded HFMS; GMFM; Gross Motor Function Measure; HFMS; Hammersmith Functional Motor Scale for SMA; MFM; MFM D1; MFM D2; MFM D3; MoHFMS; Mobility limitation; Modified HFMS; Motor Function Measure; Motor Function Measure, Dimension 1 subscore; Motor Function Measure, Dimension 2 subscore; Motor Function Measure, Dimension 3 subscore; Muscle weakness; Muscular atrophy, spinal; Neuromuscular diseases; Rehabilitation; SMA; SMN; SRM; spinal muscular atrophy; standardized response mean; survival motor neuron