Research Report
Population: Pediatric
Regina T. Harbourne, PT, PhD, PCS, Assistant Professor, Duquesne University harbourner@duq.edu
Sarah Berger, PhD, Associate Professor, City University of New York, Staten Island Sarah.Berger@csi.cuny.edu
Keywords: Prediction, variability, infant posture, Postural Control
Purpose/hypothesis: Pediatric therapists often use pelvic and trunk alignment in the sitting position as an early marker of postural ability in infants with or at risk for cerebral palsy. Intervention activities, such as active movement facilitation/practice or supportive equipment, result from judgements based on visual postural analysis. In addition, recent studies point to the positive predictive value of early variable movements in infancy for detecting neuromotor disorders. However, differential prediction of the progression of skill, based on early analysis of sitting postural assessment, has not been studied. The purpose of this study was to examine the predictive relationship of kinematic measures of the pelvis and trunk, and a novel measure of early sitting variability, Eulerian video magnification, to predict sitting skill. A secondary purpose was to determine if the novel technique of Eulerian video magnification was able to differentiate between movement variability of typically developing infants, and infants at risk for a neuromotor disorder.
Number of subjects: Twenty-two infants with or at risk for a neuromotor disorder (age 15 months, +/- 3 months) and 12 infants with typical development (age 5 months, +/- 1 month)
Materials/Methods: Infants were videotaped in a motion analysis lab. Triangular markers placed on the pelvis and upper thorax allowed 3D measurement of movement while the infants held a static prop sitting position. We used only the sagittal view for the kinematic analysis. All infants were only able to prop sit and were unable to sit without arm support for more than a few seconds; a sample of 15 seconds was selected with the infant attending to a toy and sitting still. A Vicon motion analysis system calculated average pelvic angle and average thorax angle from the markers, sagittal view. Eulerian video magnification was used to exaggerate the small movements of the infant’s trunk and pelvis, and lateral pelvic movements were counted from a back video view of each infant. The SPSS statistical program was used to compare pelvic, thorax, and Eulerian movement between infants with typical development and infants with neuromotor disorders. Regression analysis was used to calculate the contribution of these 3 selected variables to the score on the Gross Motor Function Measure (GMFM) (sitting section), which was done 2 months later, for the infants with neuromotor disorders.
Results: Significant differences for pelvic angle (P=0.001) and variable movement (Eulerian) (P=0.000) were found between groups, but no difference was found for thorax angle. Linear regression, when all three variables were entered at once, revealed that only variable movement (Eulerian) contributed significantly (R=.49; P=0.023) to GMFM scores.
Clinical relevance: Eulerian video magnification may assist therapists to evaluate small variable movements of the trunk and pelvis which may help to predict progression of sitting postural control. This novel technique may also help to evaluate if an intervention is affecting movement variability, which may in turn lead to acquisition of new skill.
Citation:
Harbourne, Regina T., PT, PhD, PCS; Berger, Sarah , PhD. Magnification of variable movements help predict sitting ability in infants with neuromotor disorder.. Poster Presentation. IV STEP Conference, American Physical Therapy Association, Columbus, OH, July 17, 2016. Online. https://u.osu.edu/ivstep/poster/abstracts/093_harbourne-berger/