Freya is a 6-year-old girl with ataxic cerebral palsy. She moved to California from Iowa last month and has been prescribed six months of physical therapy. Freya’s parents are concerned; she has been having difficulty going down the front stairs of their new home. As her physical therapist, do I have a standardized test that will measure her initial gross motor function? In six months, how will I determine whether Freya has made statistically significant progress?
My Gross Motor Function Measure User’s Manual is tattered. I could not work without the GMFM! Like all things that are well designed, the creators have taken a complex concept and made it logical and simple. The GMFM is an evaluative measure that assesses change in motor function over time. I can test Freya in January, provide PT 1x/week and then retest in July to determine if she has made significant progress. In addition, I won’t overlook Freya’s inability to reach across midline while I am heavily focused on her stair skills; the test covers all domains from lying and rolling up to running and jumping, with each skill being incrementally harder than the last.
The Gross Motor Function Measure is standardized for children with cerebral palsy or Down syndrome, aged 5 months to 16 years. It is used internationally and has become the gold standard evaluative measure of motor function designed for quantifying change in the gross motor abilities of children with cerebral palsy. It is widely respected and used in both clinical and research settings. The full version of the GMFM has 88 items. A shortened 66 item version (GMFM-66) is specific to cerebral palsy.
The GMFM is criterion referenced; each gross motor skill is scored to note its presence or absence (or emergence). Activities are assigned a score of 0 to 3, (Generally: 0 unable, 1 attempted, 2 partially accomplished, 3 completed). The user’s guide is essential to rate many items, even after familiarity with the test, hence my book’s tattered condition. The GMAE-2 scoring program is available through the CanChild website. This is the new version of the scoring program. It provides both GMFM-66 scores and gives the GMFM-66 Basal and Ceiling. It is helpful to mention that the GMFM is responsive to change. If a child has learned new skills during physical therapy, their GMAE score will most often increase to reflect this. This supports continuing PT!
Intertester reliability is high when using the GMFM; different testers obtain similar scores on the same child if they test at the same time. When Freya came from Iowa, she came with a GMFM scored just 4 months before. Retesting at her intake, it was clear that she had declined in the running and jumping domain during the interim, and that she had historically had difficulty descending stairs using one rail. Testing her at the end of her six months, it was clear that she had regained and surpassed her old scores in the running and jumping domain and that she was able to descend stairs using one rail for support. The scores showed statistically significant improvement from both her Iowa score and the initial intake score . In addition, Freya was happy with her ability to walk down to the car by herself and her family was highly satisfied.
I hope you can see from my enthusiasm, it is worth while to spend a session scoring this measure. There are so many ways to use the raw data and scores from the GMFM. I will discuss these in future posts.