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Published on: August 9, 2024
Comprehensive quantification of the spastic catch in children with cerebral palsy
Bar-On Lynn1, Aertbeliën Erwin, Molenaers Guy
1University Hospital, Pellenberg, Clinical Motion Analysis Laboratory, Weligerveld 1, 3212 Pellenberg, Belgium. lynn.1.bar-on@uzleuven.be
Insights
Objective measures can now quantify the spastic catch in children with cerebral palsy (CP). This study found that biomechanical parameters, combined with electromyography (EMG) data, offer a reliable way to assess spasticity severity.
Area of Science:
- Biomedical Engineering
- Clinical Biomechanics
- Pediatric Neurology
Background:
- Spastic catch, a key indicator of spasticity in cerebral palsy (CP), is currently assessed subjectively in clinical practice.
- Objective quantification of spastic catch is needed to improve diagnostic accuracy and treatment monitoring in children with CP.
Purpose of the Study:
- To evaluate the psychometric properties of objective biomechanical parameters for defining and quantifying spastic catch severity in children with spastic CP.
- To assess the reliability and validity of different definitions of the angle of spastic catch (AOC).
Main Methods:
- Forty-six children with spastic CP (age 4-16) underwent objective spasticity assessments using high-velocity passive stretches.
- Surface electromyography (sEMG), inertial sensors, and a force sensor measured muscle activity, joint angles, and reactive torque.
- Three biomechanical definitions of AOC were derived and correlated with RMS-EMG and the Modified Tardieu Scale (MTS).
Main Results:
- All three AOC definitions demonstrated moderate to high reliability upon retesting.
- Weak but significant correlations were observed between the third AOC definition (AOC3) and MTS/RMS-EMG for both gastrocnemius and medial hamstrings.
- AOC3 successfully differentiated between mild, moderate, and severe spastic catches.
Conclusions:
- Objective biomechanical parameters, particularly AOC3, can reliably define and quantify spastic catch severity in children with CP.
- Integrating biomechanical data with RMS-EMG provides a more comprehensive understanding of spastic catch.
- These objective measures hold potential for improved clinical assessment and management of spasticity in pediatric CP.
Abstract:
In clinical settings, the spastic catch is judged subjectively. This study assessed the psychometric properties of objective parameters that define and quantify the severity of the spastic catch in children with cerebral palsy (CP). A convenience sample of children with spastic CP (N=46; age range: 4-16 years) underwent objective spasticity assessments. High velocity, passive stretches were applied to the gastrocnemius (GAS) and medial hamstrings (MEH). Muscle activity was measured with surface electromyography (sEMG), joint angle characteristics using inertial sensors and reactive torque using a force sensor. To test reliability, a group of 12 children were retested after an average of 13 ± 9 days. The angle of spastic catch (AOC) was estimated by three biomechanical definitions: joint angle at (1) maximum angular deceleration; (2) maximum change in torque; and (3) minimum power. Each definition was checked for reliability and validity. Construct and clinical validity were evaluated by correlating each AOC definition to the averaged root mean square envelope of EMG (RMS-EMG) and the Modified Tardieu Scale (MTS). Severity categories were created based on selected parameters to establish face validity. All definitions showed moderate to high reliability. Significant correlations were found between AOC3 and the MTS of both muscles and the RMS-EMG of the MEH, though coefficients were only weak. AOC3 further distinguished between mild, moderate and severe catches. Objective parameters can define and quantify the severity of the spastic catch in children with CP. However, a comprehensive understanding requires the integration of both biomechanical and RMS-EMG data.
