Dynamic postural control in patients with hemiparesis

Decreased postural stability is a common problem associated with hemiparesis secondary to stroke. The purpose of this study was to evaluate dynamic postural control in patients with hemiparesis and in normal subjects matched for age. Quantitative posturography (EquiTest System) was performed to assess the response of subjects to sudden perturbations. A total of 59 patients with hemiparesis and 98 healthy volunteers were evaluated. All the patients were able to walk inside their house without lower limb orthoses. Both the patients and the healthy volunteers were subjected to forward and backward perturbations while standing on a movable force platform. Balance responses were analyzed in terms of weight symmetry, latency, amplitude (relative response strength), and strength symmetry. They were also subjected to toes-up and toes-down perturbations to evaluate their response to a disruptive balance force. The response latency to perturbations was longer and the response strength was weaker on the paretic side of patients with hemiparesis. The dynamic postural control was impaired in patients with hemiparesis as compared with healthy subjects. The results suggest that patients with hemiparesis tend to fall easily and that the risk of falls toward the paretic side is high.