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Updated: Jun 4, 2026
Measurements of Motor Function and Other Clinical Outcome Parameters in Ambulant Children with Duchenne Muscular Dystrophy
Published on: January 12, 2019
Validity and reliability of two abbreviated versions of the Gross Motor Function Measure
Laura K Brunton1, Doreen J Bartlett
1Faculty of Health Sciences, The University of Western Ontario, 1011c Elborn College, 1201 Western Rd, London, Ontario, Canada. brunton.laura@gmail.com
Background:
The "gold standard" for measuring gross motor function in children with cerebral palsy is the 66-item Gross Motor Function Measure (GMFM-66).
Objective:
The purpose of this study was to estimate the validity and reliability of 2 abbreviated versions of the GMFM-66; one version involves an item set approach, and the other version involves a basal and ceiling approach.
Design:
This was a measurement study comprising concurrent validity, comparability, and test-retest reliability components.
Methods:
The study participants were 26 children who were 2 to 6 years of age and had cerebral palsy across all Gross Motor Function Classification System levels. In the first session, both abbreviated versions were administered by 2 independent raters; next, the full GMFM-66 was administered. In the second session, only the abbreviated versions were administered by the same raters. Concurrent validity, comparability of versions, and test-retest reliability were determined with intraclass correlation coefficients [ICC (2,1)].
Results:
Both versions demonstrated high levels of validity, with an ICC of .99 (95% confidence interval=0.972-0.997), reflecting associations with the GMFM-66. Both versions also were shown to be highly reliable, with ICCs of greater than .98 (95% confidence interval=0.965-0.994).
Limitations:
A smaller-than-expected sample was recruited for this study and may be a potential limitation of the study.
Conclusion:
Both versions of the GMFM-66 can be used in clinical practice or research. However, the GMFM-66 with the basal and ceiling approach is recommended as the preferred abbreviated version.
