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Postural control in children with spastic diplegia: muscle activity during perturbations in sitting
E Brogren1, M Hadders-Algra, H Forssberg
1Department of Woman and Child Health, Karolinska Institute, Stockholm, Sweden.
Insights
Children with spastic diplegia exhibit altered muscle responses during sitting equilibrium. Their automatic postural adjustments show reversed muscle recruitment and co-activation, impacting balance control.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Pediatric Rehabilitation
Background:
- Understanding neural control of sitting equilibrium is crucial for optimizing posture in children with cerebral palsy (CP).
- Previous research indicates potential differences in postural adjustments in individuals with CP.
Purpose of the Study:
- To investigate the neural mechanisms underlying equilibrium control during sitting in children with spastic diplegia.
- To compare automatic postural adjustments (APAs) in response to support surface perturbations between children with spastic diplegia and typically developing controls.
- To inform optimal sitting positions for children with CP based on their postural control capabilities.
Main Methods:
- Seven children with spastic diplegia and seven age-matched controls participated.
- Automatic postural adjustments were measured during sitting following sudden backward sway of the support surface.
- Muscle recruitment patterns, including order and co-activation of antagonistic muscles, were analyzed.
Main Results:
- Both groups exhibited brisk responses in ventral muscles.
- Children with spastic diplegia showed a reversed order of muscle recruitment compared to controls, with initial activation in neck flexors instead of caudal muscles.
- Children with spastic diplegia demonstrated co-activation of antagonistic neck and hip muscles.
Conclusions:
- Children with spastic diplegia can generate basic muscle activation patterns (first level of central pattern generators, CPGs).
- They exhibit impaired ability to adjust these patterns in response to external perturbations (second level of CPGs).
- These findings highlight specific motor control deficits affecting sitting balance in spastic diplegia and have implications for therapeutic interventions.
Abstract:
To clarify the neural mechanisms controlling equilibrium during sitting, and the implications for the optimal sitting position for children with CP, automatic postural adjustments after perturbations of the support surface during sitting were investigated in seven children with spastic diplegia and in seven age-matched controls. A sudden backward sway of the body evoked brisk responses in ¿ventral' muscles in both groups. However, the order of muscle recruitment, which in most non-disabled children was caudal, was reversed in the children with diplegia, whose first response was in the neck flexors. The children with diplegia also co-activated antagonistic neck and hip muscles. The authors concluded that although children with spastic diplegia may produce a basic muscle activation pattern (first level of the central pattern generator, CPG), they cannot adjust the pattern in response to external changes (second level of the CPG).