Construct Validity of a Task-Oriented Bimanual and Unimanual Strength Measurement in Children With Unilateral Cerebral Palsy.
Mellanie Geijen, Eugene Rameckers, Caroline Bastiaenen and 2 others
PMID 32936866WHAT IT FOUND
A new measure of task-oriented strength in children with unilateral cerebral palsy correlates moderately with grip strength but poorly with functional skill scores.
It captures strength during lifting tasks, not general manual dexterity or parent-reported performance, so it adds distinct information rather than replacing existing assessments.
Key findings
01Task-oriented peak force during crate and pitcher lifting showed moderate positive correlations (0.493 to 0.687) with maximal grip strength, indicating related but distinct constructs.
02Correlations with functional outcome measures were low, ranging from 0.086 to 0.387 for manual skills and speed tests, and negative for parent-reported performance.
03Eight of ten a priori hypotheses regarding construct validity were supported, suggesting the measure is valid for assessing strength during specific activities but not general function.
STILL TO COME
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What it does not show
The study used existing data from three separate trials, so not every child completed every comparator measure, leading to varying sample sizes for different correlations. Comparators were not chosen specifically for this validity study, which may have affected the strength of the relationships observed. A high percentage (64%) of children could not perform the pitcher task with their affected hand, limiting the data available for that specific measure. The negative correlations with parent-reported performance may reflect a mismatch between the specific physical task and the broader daily activities parents report on. This was a cross-sectional study, so it does not show whether the measure is sensitive to change over time (responsiveness).
Declared interests
The funder played no role in the design, conduct, or reporting of this study.
The easy way to misread this
Do not assume that a child's score on this task-oriented strength measure predicts their overall manual dexterity or daily life performance. The correlations with functional skill and parent-reported outcomes were low, meaning this tool measures specific lifting capacity, not general hand function.