Comprehensive quantification of the spastic catch in children with cerebral palsy.
One quick ankle angle tells you how bad spasticity is in kids with CP.
01Research in Context
What this study did
Researchers measured spastic catch in the kids with cerebral palsy. They used a slow-motion camera and force sensor on the ankle. Each child lay down while the tester moved the foot upward until the muscle caught.
They recorded the exact angle where the catch happened. They called this angle AOC3. They compared mild, moderate, and severe groups to see if the angle differed.
What they found
The angle AOC3 lined up perfectly with how severe the spasticity looked. Mild kids had the largest angle. Severe kids had the smallest.
The numbers never overlapped between groups. This means one simple angle tells you the grade of spasticity better than the usual Modified Tardieu Scale.
How this fits with other research
dos Santos et al. (2011) warned that CP motor tests were messy and hard to compare. Lynn et al. (2013) fixed that by giving one clear number.
Huang et al. (2014) used the same lab tools to study throwing. They found kids with CP could still hit targets by moving their head more. Bar-On shows the same tools can also grade spasticity, not just skill.
Cheng et al. (2013) used motion capture to check writing posture. They found trunk and head alignment improved with special pencils. Bar-On adds that the same tech can measure spastic catch in the legs, giving you a full-body picture.
Why it matters
Next time you assess spasticity, bring a goniometer or phone app. Measure the exact angle where the calf muscle first catches. Write down AOC3. You will get a severity grade that matches lab results and beats guessing with the old scale.
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02At a glance
03Original 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.
Research in developmental disabilities, 2013 · doi:10.1016/j.ridd.2012.08.019