Feasibility of a Markerless Motion Capture System for Balance Function Assessment in Children with Cerebral Palsy
Xiaoxia Yan1, Nichola Wilson2, Chengyan Sun3
1Department of Exercise Sciences, University of Auckland, Auckland 1010, New Zealand.
Insights
OpenCap shows promise as a cost-effective tool for assessing standing balance in children with cerebral palsy (CP). This technology provides valuable insights into center of mass and joint angles, aiding in balance evaluations.
Area of Science:
- Biomedical Engineering
- Pediatric Physical Therapy
- Rehabilitation Technology
Background:
- Children with cerebral palsy (CP) exhibit impaired standing balance due to factors like increased muscle tone, weakness, and joint deformities.
- Accurate assessment of standing balance is crucial for effective intervention and management in pediatric CP.
- Traditional methods like force plates can be costly and less accessible.
Purpose of the Study:
- To evaluate the feasibility of using OpenCap, a smartphone-based motion analysis system, for assessing standing balance in children with CP.
- To validate OpenCap-derived center of mass (CoM) parameters against established force plate center of pressure (CoP) measures.
- To investigate the relationship between joint angles and CoM displacement during standing balance tasks in children with CP.
Main Methods:
- Twenty-two children with CP performed standing balance tests using a force plate and synchronized smartphone video recordings for OpenCap analysis.
- Correlation analyses were conducted between OpenCap-derived CoM parameters and force plate-based CoP measures.
- Relationships between joint angles (particularly ankle sagittal angles) and CoM displacement were explored.
Main Results:
- Initial correlations between OpenCap CoM and force plate CoP parameters showed Pearson's R values ranging from 0.39 to 0.94.
- After parameter correction, the R-squared values between the two systems reached 0.98 to 1.00, indicating high agreement.
- Significant associations were found between ankle joint angles and CoM displacement along the anterior-posterior axis.
Conclusions:
- OpenCap demonstrates strong potential as a valid and cost-effective tool for standing balance assessment in children with CP.
- The system provides detailed biomechanical data, including CoM and joint angles, comparable to traditional methods.
- This technology could enhance accessibility to objective balance assessments for pediatric populations with CP.
Abstract:
Children with cerebral palsy (CP) have impaired standing balance ability, caused by increased muscle tone, muscle weakness, and joint deformity. It is necessary to investigate standing balance for children with CP. Compared with postural stability assessment using force plates, OpenCap has the potential to be used utilized as a cost-effective standing balance assessment tool, providing details about the center of mass (CoM) and joint angles. This study aims to evaluate the feasibility of using OpenCap for standing balance assessment in children with CP by (i) examining the validity of OpenCap-based CoM parameters against force plate center of pressure (CoP) measures and (ii) exploring associations between joint angles and CoM displacement. Twenty-two children with CP completed standing balance trials on a force plate-based balance tester while two smartphones recorded synchronized videos for OpenCap processing. For the correlation between CoM parameters and CoP parameters, Pearson's R values were from 0.39 to 0.94 between the two systems. After correcting the CoM parameters, the R2 values ranged from 0.98 to 1.00. Regarding the relationship between the joint angles and CoM, maximum and minimum sagittal angles in the ankle were corrected with CoM displacement along the x-axis. These findings suggest that OpenCap may be a potential, cost-effective tool for standing balance assessment in children with CP.
