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Influence of two different sitting positions on postural adjustments in children with spastic diplegia
E Brogren1, H Forssberg, M Hadders-Algra
1MotorikLab, Astrid Lindgren Children's Hospital, Stockholm, Sweden. eva.brogren@swipnet.se
Insights
Children with spastic diplegia exhibit impaired postural control, not caused by their crouched sitting position. This posture may actually help manage sensory-motor instability in cerebral palsy.
Area of Science:
- Neuroscience
- Developmental Pediatrics
- Biomedical Engineering
Background:
- Children with spastic diplegia often display atypical postural adjustments.
- The role of sitting posture versus underlying neural deficits in these adjustments is unclear.
Purpose of the Study:
- To investigate whether deviant postural adjustments in spastic diplegia stem from a crouched sitting position or a neural deficit.
- To compare postural control in erect versus crouched sitting positions in children with and without cerebral palsy.
Main Methods:
- Assessed postural adjustments in 10 children with spastic diplegia and 10 controls (ages 3-7.5) using surface EMGs and kinematics.
- Recorded muscle activity (neck, trunk, legs) and movement (head, body sway, pelvis) during platform translations.
- Compared responses in erect and crouched sitting positions.
Main Results:
- Typically developing children adapted postural adjustments to sitting position.
- Children with cerebral palsy (CP) showed reduced adaptational capacity, more in erect than crouched positions.
- The crouched position appeared to mitigate sensory-motor instability in CP.
Conclusions:
- The crouched sitting position does not induce postural deficiency in spastic diplegia but may be compensatory.
- Severe spastic diplegia involves a basic deficit in postural control, lacking direction specificity in leg muscles.
- Mild-to-moderate CP involves intact basic postural control, with dysfunctions in task-specific tuning.
Abstract:
The present study addressed the question whether the deviant postural adjustments in children with spastic diplegia can be attributed to their crouched sitting position or primarily to their neural deficit. Postural adjustments during sitting in an erect and in a crouched position on a movable platform were assessed in 10 children, aged 3 to 7 years 6 months, with mild-to-severe forms of spastic diplegia and 10 age- and sex-matched control children. Multiple surface EMGs of neck, trunk, and leg muscles and kinematics of head, body sway, and pelvis were recorded during forward and backward translations. The children with normal motor development showed a distinct adaptation of postural adjustments to sitting position. The children with cerebral palsy (CP) had a deficient adaptational capacity which was more pronounced in the erect than in the crouched position. Thus, the crouched sitting position did not induce postural deficiency but seemed to offer a solution to the sensory-motor problem of the instability experienced. Children with severe diplegia exhibited a lack of direction specificity in the leg muscles during backward body sway, which points to a basic deficit in postural control. In addition, these children showed marked dysfunctions in the precise tuning of the postural adjustments to task-specific conditions. In the children with mild-to-moderate forms of CP the basic level of control was intact.