Article Review: Selective motor control and gross motor function in bilateral cerebral palsy
Purpose: Investigate the relationship between the Selective Control Assessment of the Lower Extremity (SCALE), muscle volume, Gross Motor Function Measure (GMFM-66), and the Modified Ashworth Scale (MAS) in individuals with cerebral palsy.
Study Population: The population recruited for this study included 11 male participants between the age of 12 to 25 years old with a diagnosis of bilateral spastic CP and were a level I-IV on the Gross Motor Function Classification System. Those who had underwent surgery, serial casting, or had been given botox injections in the past year were excluded.
Methods/Intervention: In order to obtain muscle volume, all participants underwent a magnetic resonance image (MRI) of both lower extremities to obtain imaging for 18 muscles in each lower extremity. Muscle volumes were averaged between both lower extremities and normalized to body mass. The measurements were obtained by two examiners, and inter-rater reliability was established.
Outcome Measures: On the same day as the MRI, functional outcome measures were given including the SCALE, MAS, and GMFM-66. All functional outcome measures were assessed by a single physiotherapist. No specific interventions were utilized during this particular study.
Results: Overall, the study results showed that the test for gross motor function, the GMFM-66, was strongly correlated to the SCALE (r=0.901, p≤0.001) and lower extremity muscle volume (r=0.750, p=0.008). In other words, participants that presented with improved scores on the GMFM-66 also had more muscle volume and selective motor control. Additionally the MAS was significantly correlated with the GMFM-66 (r=-0.691, p=0.018). No other relationships were noted.
Strengths/Limitations: The strengths of the article include establishing inter-rater reliability among the MRI assessors, and the use of one physiotherapist to limit any variability of results. Limitations to the study include the small sample size and possible variation of results due to puberty given the age of the participants.
Conclusion: Gross motor function as measured by the GMFM-66 was positively related to the SCALE and muscle volume, and MAS was correlated with the GMFM-66. The strong relationship observed between the SCALE and GMFM-66 compared to the other tests would suggest that selective motor control could be a major factor in determining a person with CP’s gross motor function. Further research is needed to continue validating the results of the study.
Reference: Noble JJ, Gough M, Shortland AP. Selective motor control and gross motor function in bilateral spastic cerebral palsy. Developmental Medicine & Child Neurology. 2019 Jan; 61(1):57-61.
2 responses to “Article Review: Selective motor control and gross motor function in bilateral cerebral palsy”
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Great review! I agree that the small sample size is a limiting factor for the study, however I like how they looked at participants within a large age range. I find it interesting that the GMFM is correlated to both muscle volume and selective muscle control. I feel that this gives us as future therapists a good indicator of which outcome measure would be appropriate to use based off of deficits we may see.
Absolutely! I do believe however given the large age range and small sample size that more research is needed to see differences among pre-pubescent and and pubescent age children. A lot of growth occurs within the age group studied and I would be interested in seeing if differences begin to emerge with a larger sample size in an age group that is 12-14 verses 15-18 for example.