Children with cerebral palsy exhibit greater and more regular postural sway than typically developing children

Abstract

Following recent advances in the analysis of centre-of-pressure (COP) recordings, we examined the structure of COP trajectories in ten children (nine in the analyses) with cerebral palsy (CP) and nine typically developing (TD) children while standing quietly with eyes open (EO) and eyes closed (EC) and with concurrent visual COP feedback (FB). In particular, we quantified COP trajectories in terms of both the amount and regularity of sway. We hypothesised that: (1) compared to TD children, CP children exhibit a greater amount of sway and more regular sway and (2) concurrent visual feedback (creating an external functional context for postural control, inducing a more external focus of attention) decreases both the amount of sway and sway regularity in TD and CP children alike, while closing the eyes has opposite effects. The data were largely in agreement with both hypotheses. Compared to TD children, the amount of sway tended to be larger in CP children, while sway was more regular. Furthermore, the presence of concurrent visual feedback resulted in less regular sway compared to the EO and EC conditions. This effect was less pronounced in the CP group where posturograms were most regular in the EO condition rather than in the EC condition, as in the control group. Nonetheless, we concluded that CP children might benefit from therapies involving postural tasks with an external functional context for postural control.

Fig. 1

Effects of group (CP and TD children, represented by black and grey bars, respectively) and condition (EO, EC and FB) on the ‘amount of sway’ (upper panels, mean sway amplitude r_mean and sway path of the conventional posturogram SP) and on the ‘regularity of sway’ (lower panels, sway path of the normalised posturogram SP_n and sample entropy SEn; note that lower SEn values imply more regular posturograms). Error bars represent the standard error