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Evaluation of the catch in spasticity assessment in children with cerebral palsy
Josien C van den Noort1, Vanessa A Scholtes, Jules G Becher
1Department of Rehabilitation Medicine, Research Institute MOVE, Vrije Universiteit University Medical Center, 1007 MB Amsterdam, The Netherlands. j.vandennoort@vumc.nl
Insights
In children with cerebral palsy (CP), a catch during spasticity assessment is caused by increased muscle activity during fast passive stretching. This finding confirms the role of muscle hyperexcitability in CP spasticity.
Area of Science:
- Neurology
- Pediatrics
- Rehabilitation Medicine
Background:
- Spasticity is a common motor disorder in children with cerebral palsy (CP).
- Clinical assessment of spasticity often involves evaluating the
- catch,
- a sudden increase in resistance to passive movement.
Purpose of the Study:
- To determine if the catch observed in clinical spasticity assessments in children with CP results from a velocity-dependent increase in muscle activity due to stretch reflex hyperexcitability.
Main Methods:
- A cross-sectional study involving 20 children with CP (aged 5-14 years).
- Spasticity was assessed using slow and fast passive stretches on specific lower limb muscles (medial hamstrings, soleus, medial gastrocnemius).
- Surface electromyography (EMG) and joint motion were recorded simultaneously to compare examiner-perceived catches with muscle activity bursts.
Main Results:
- A sudden increase in muscle activity, or
- burst,
- was observed during fast passive stretching in 100% of hamstring, 95% of soleus, and 84% of medial gastrocnemius assessments.
- The average rectified value (ARV) of EMG signals was significantly lower during slow passive stretches.
Conclusions:
- The findings confirm that increased muscle activity is the primary cause of the catch experienced during fast passive muscle stretching in children with CP.
- This validates the hypothesis that stretch reflex hyperexcitability contributes significantly to spasticity in this population.
Objective:
To evaluate whether the catch in clinical spasticity assessment in cerebral palsy (CP) is the consequence of a sudden velocity-dependent increase in muscle activity, resulting from hyperexcitability of the stretch reflex in spasticity.
Design:
Cross-sectional study.
Setting:
A special school for children with physical disabilities.
Participants:
Children with CP (N=20; age range, 5-14y; mean weight +/- SD, 35+/-14kg; mean length +/- SD, 139+/-19cm).
Interventions:
Spasticity assessment tests (using slow and fast passive stretch) were performed in the medial hamstrings, soleus, and medial gastrocnemius muscles of the children by 2 experienced examiners.
Main Outcome Measures:
Surface electromyography (EMG) was recorded and joint motion was simultaneously measured using 2 inertial sensors. The encounter of a catch by the examiner was compared with the presence of a sudden increase in muscle activity ("burst"). The average rectified value (ARV) of the EMG signal was calculated for each test.
Results:
The study shows a sudden increase in muscle activity in fast passive stretch, followed by a catch (hamstrings 100%, soleus 95%, gastrocnemius 84%). The ARV in slow passive stretch was significantly lower.
Conclusions:
The results confirm that in children with CP, an increase in muscle activity is primarily responsible for a catch in fast passive muscle stretch.
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