Functional Task Constraints Foster Enhanced Postural Control in Children With Cerebral Palsy.

Background: Postural instability is a classical characteristic of cerebral palsy (CP), but it has not been examined during functional play activity. Recent work has demonstrated that when motor tasks are made functionally more relevant, performance improves, even in children with movement pathology. It is possible that in a disease state, the underlying control mechanisms that are associated with healthy physiology must be elicited.

Deterministic center of pressure patterns characterize postural instability in Parkinson's disease.

Static posturographic recordings were obtained from six Parkinson's patients and six age-matched, healthy control participants. The availability of vision and visuo-spatial cognitive load were manipulated. Postural sway patterns were analyzed using recurrence quantification analysis (RQA), which revealed differences in center of pressure (COP) dynamics between Parkinson's and control participants.

Dynamic patterns of postural sway in ballet dancers and track athletes.

We compared the variability and spatiotemporal profile of postural sway of trained ballet dancers to college varsity track athletes under variations in the availability of vision and rigidity of the support surface. We found no differences between the groups according to the variability measures, but variability increased for both groups with eyes closed and on a foam surface. Recurrence quantification analysis revealed that the postural sway of dancers was less regular (lower recurrence), less stable (lower maxline), less complex (lower entropy), and more stationary (lower absolute trend) than that of track athletes.

Inverse relation between postural variability and difficulty of a concurrent short-term memory task.

We measured postural stability while participants simply stood or stood while performing a digit rehearsal task of varying levels of difficulty in order to examine the effects on postural control of concurrent short-term memory demands. The rehearsal task manipulation avoided factors that contaminate postural sway measurements, such as vocal articulation or visual fixation during posture data collection. When participants performed the more difficult digit tasks (longer digit strings), postural sway was reduced relative to when performing an easy version of the task (few digits).