To investigate whether some of the abnormalities in the postural adjustments of children with spastic cerebral palsy (CP) can be explained by their typical (more crouched) sitting position.

Design: Neurophysiological assessment of postural adjustments.

Setting: Laboratory setting.

Patients: Ten children with various forms of bilateral spastic CP aged 3 to 7.5 years and ten age- and sex-matched typically developing children.

Measurement and main Results: The children were seated on a movable platform in two different sitting conditions: with crossed legs, causing an erect sitting position ,and with straight legs, causing a crouched sitting position. They were exposed to a random series of forward and backward translations. Multiple surface EMGs of neck, trunk, and leg muscles, and kinematics were recorded. The data revealed that the abnormalities in postural adjustments could not be attributed to the crouched position. The three children with severe diplegia exhibited a basic deficit in postural control. They displayed a lack of leg muscle activation appropriate to the direction of the perturbing stimulus. In children with mild to moderate forms of CP, the basic direction-specific organization of the postural adjustments was intact. However, they had problems in adjusting postural activity to body configuration, especially in the erect sitting position, whereas typically developing children exhibited a well-adapted position-specific postural modulation. In general the postural deficit in children with CP was more marked during backward body sway than during forward body sway. Conclusion: The crouched sitting position does not explain the different postural organization of children with CP. Rather, it might be a solution to the sensory-motor problem of the childrenÕs experienced instability. The more impaired adjustments during backward body sway might reflect the difference in stability limits in backward, compared with forward direction and/or a difference in supraspinal control of ventral versus dorsal muscles. This might imply that training should be targeted at enhancing task-specific function of the ventral muscles instead of focusing on antigravity training of the extensor muscles.

Acknowledgements: This study was supported by Fšrsta Majblommans Riksfšrbund, Stiftelsen Solstickan and RBUs Forskningsstiftelse.

Childhood Disablity Update 2005 - Conference Abstracts.Pediatric Oncall [serial online] 2006 [cited 15 January 2006(Supplement 1)];3. Available from:
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postural_adjustments_in_children_cp.asp