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Updated: Aug 13, 2026
Measurements of Motor Function and Other Clinical Outcome Parameters in Ambulant Children with Duchenne Muscular Dystrophy
Published on: January 12, 2019
Reliability of the Hammersmith functional motor scale for spinal muscular atrophy in a multicentric study
E Mercuri1, S Messina, R Battini
1Department of Paediatric Neurology, Catholic University, Largo Gemelli, 00168 Rome, Italy. e.mercuri@imperial.ac.uk
Insights
The Hammersmith functional motor scale is reliable for assessing children with spinal muscular atrophy (SMA). This validation supports its use in tracking functional changes over 3-6 months for therapeutic trials.
Area of Science:
- Neurology
- Pediatrics
- Rehabilitation Medicine
Background:
- Spinal muscular atrophy (SMA) is a severe genetic neuromuscular disorder.
- Functional motor assessment is crucial for monitoring disease progression and therapeutic efficacy in pediatric SMA patients.
Purpose of the Study:
- To validate the Hammersmith functional motor scale (HFMS) in a large cohort of non-ambulant children with SMA types 2 and 3.
- To establish the reliability and responsiveness of the HFMS over 3- and 6-month intervals.
Main Methods:
- A cohort of 90 non-ambulant children with SMA types 2 or 3 underwent baseline assessment (T0).
- Reassessments were conducted at 3 months (T1, n=66) and 6 months (T2, n=24).
- Inter-observer reliability was assessed by 3 examiners on 13 children, yielding >95% agreement.
Main Results:
- High inter-observer reliability (>95%) was confirmed for the HFMS.
- At 3 months, 68% of children showed no change in HFMS scores, and 21% varied by +/- 1 point.
- At 6 months, 37.5% showed no change, and 37.5% varied by +/- 1 point.
Conclusions:
- The study validates the Hammersmith functional motor scale's reliability and utility for children with SMA.
- The findings provide a baseline for assessing functional changes over short intervals, aiding in the evaluation of future SMA therapies.
Abstract:
The aim of this study was to validate the Hammersmith functional motor scale for children with spinal muscular atrophy in a large cohort of 90 non-ambulant children with spinal muscular atrophy type 2 or 3. All had a baseline assessment (T0) and were reassessed either at 3 months (T1) (n = 66) or at 6 months (T2) (n = 24). Inter-observer reliability, tested on 13 children among 3 examiners, was > 95%. Of the 66 children examined after 3 months 4 had adverse effects in between assessments and were excluded from the analysis. Forty-two (68%) of the remaining 62 reassessed had no variation in scores between T0 and T1 and 13 (21%) were within +/- 1 point. 9 (37.5%) of the 24 children reassessed after 6 months had no variation in scores between T0 and T2 and another 9 (37.5%) had variations within +/- 1 point. Our study confirms previous observations of the reliability of the scale and helps to establish a baseline for assessing changes of functional ability over 3 and 6 month intervals. This information can be valuable in view of therapeutic trials.
