Reliability of the modified hammersmith functional motor scale in young children with spinal muscular atrophy

Abstract
Introduction: The test–retest reliability of the Modified Hammersmith Functional Motor Scale (MHFMS) in children with spinal muscular atrophy (SMA) ≤30 months of age was assessed. The age at which typically developing children (TD) achieve maximum MHFMS scores was also studied. Methods: Twenty‐two children with SMA type II [mean age (SD) = 20 (5) months, range 9–30 months) were tested twice using the MHFMS. Twenty‐five TD children [mean age (SD) = 18 (7) months, range 9–30 months) were tested once. Results: The average difference between MHFMS scores for SMA children was 0.18 [first assessment: mean (SD) = 12.8 (9.8); second assessment: mean (SD) = 13.0 (8.8)]. Reliability was excellent (ICC1,3 = 0.96, SEM 1.86). TD participants had MHFMS scores ranging from 36 to 40 [mean (SD) = 39.2 (1.2)] and achieved maximum test scores at 12 months of age. Discussion: MHFMS scores in young children with SMA type II showed excellent test–retest stability. This suggests that the MHFMS can be used reliably in this younger population for clinical trials and follow‐up. Muscle Nerve, 2011
Funding Information
  • Public Health Services (UL1-RR025764)
  • National Center for Research Resources (C06-RR11234)