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Updated: Mar 6, 2026
Measurements of Motor Function and Other Clinical Outcome Parameters in Ambulant Children with Duchenne Muscular Dystrophy
Published on: January 12, 2019
[Upper limb functional assessment scale for children with Duchenne muscular dystrophy and Spinal muscular atrophy]
Raúl G Escobar1, Nayadet Lucero2, Carmen Solares3
1Unidad de Neurología, División de Pediatría, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
Insights
A new scale reliably assesses upper limb function in children with Duchenne muscular dystrophy (DMD) and Spinal muscular atrophy (SMA). This validated tool is easy to use, even with self-trained evaluators, aiding disease progression monitoring.
Area of Science:
- Neurology
- Rehabilitation Medicine
- Pediatric Clinical Assessment
Background:
- Duchenne muscular dystrophy (DMD) and Spinal muscular atrophy (SMA) lead to significant disability and functional decline.
- Objective assessment tools are crucial for monitoring disease progression and treatment efficacy, especially in advanced stages.
Purpose of the Study:
- To develop and validate a scale for evaluating upper limb (UL) function in pediatric patients with DMD and SMA.
- To incorporate a self-training module for evaluators to ensure consistent scale application.
Main Methods:
- Scale development involved literature review, pilot testing in healthy children and DMD patients, and evaluator training using a handbook and video.
- The final scale was administered to children with DMD and SMA.
- Reliability was assessed via Cronbach's alpha, Kendall's W, and intra/inter-rater test-retest.
- Validity was evaluated through concordance analysis and factor analysis.
Main Results:
- The scale demonstrated high reliability: internal consistency (Cronbach's α = 0.97), inter-rater concordance (Kendall's W = 0.96), and intra-rater concordance (r = 0.97–0.99).
- Validity was confirmed by the lack of significant differences between evaluators and an expert (F = 0.023, p > .5).
- Factor analysis indicated that four factors explained 85.44% of the total variance.
Conclusions:
- The developed scale is a reliable and valid instrument for assessing UL functionality in children with DMD and SMA.
- The scale's ease of implementation, facilitated by self-training and simple materials, supports its widespread clinical use.
Abstract:
Duchenne muscular dystrophy (DMD) and Spinal muscular atrophy (SMA) causes significant disability and progressive functional impairment. Readily available instruments that assess functionality, especially in advanced stages of the disease, are required to monitor the progress of the disease and the impact of therapeutic interventions.
Objective:
To describe the development of a scale to evaluate upper limb function (UL) in patients with DMD and SMA, and describe its validation process, which includes self-training for evaluators.
Patients And Method:
The development of the scale included a review of published scales, an exploratory application of a pilot scale in healthy children and those with DMD, self-training of evaluators in applying the scale using a handbook and video tutorial, and assessment of a group of children with DMD and SMA using the final scale. Reliability was assessed using Cronbach and Kendall concordance and with intra and inter-rater test-retest, and validity with concordance and factorial analysis.
Results:
A high level of reliability was observed, with high internal consistency (Cronbach a = 0.97), and inter-rater (Kendall W = 0.96) and intra-rater concordance (r = 0.97 to 0.99). The validity was demonstrated by the absence of significant differences between results by different evaluators with an expert evaluator (F = 0.023, p > .5), and by the factor analysis that showed that four factors account for 85.44% of total variance.
Conclusions:
This scale is a reliable and valid tool for assessing UL functionality in children with DMD and SMA. It is also easily implementable due to the possibility of self-training and the use of simple and inexpensive materials.
