PT  - JOURNAL ARTICLE
AU  - Brunton, Laura K.
AU  - Bartlett, Doreen J.
TI  - Validity and Reliability of Two Abbreviated Versions of the Gross Motor Function Measure
AID  - 10.demo/ptj.20100279
DP  - 2011 Apr 01
TA  - Demo Journal of Physical Therapy
PG  - 577--588
VI  - 91
IP  - 4
4099  - http://demo.highwire.org/content/91/4/577.short
4100  - http://demo.highwire.org/content/91/4/577.full
AB  - 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.