Seated Postural Control in Adolescents With Idiopathic Scoliosis

In Brief Study Design. The center of pressure (COP) path in 14 adolescents with idiopathic scoliosis and 12 age-matched able-bodied adolescents was compared using traditional measures and a two-level decomposition. Objectives. To investigate whether asymmetries in the spines of children with idiopathic scoliosis are reflected in altered sway patterns in quiet sitting. Summary of Background Data. Previous studies have studied the sway of children with scoliosis while standing. However, the standing posture is typically controlled at the ankle joint. To date, there are no studies with this population of sitting sway, where the movement is controlled by the trunk muscles. Methods. Traditional measures of the COP of the trunk were analyzed. The COP was also decomposed into an approximation of the center of mass path and deviations around this path. Results. COP movement in sitting, reflecting the postural control of the spine, was decreased in adolescents with idiopathic scoliosis. Children with scoliosis had symmetric sitting COP trajectories and most measures were similar between the two groups. Conclusions. The results suggest a control strategy for maintaining a sitting posture that does not change with the development of scoliosis but does adapt by decreasing movement to maintain the trunk in a region where the it can remain “passively” stable. Adolescents with scoliosis had sway patterns of the upper body that were symmetric and in most aspects similar to controls. They did display a reduced range of movement, which is consistent with a strategy to maintain an asymmetric spine in a stable position without extra muscular effort.