Eye–hand coordination during manual object transport with the affected and less affected hand in adolescents with hemiparetic cerebral palsy

In the present study we investigated eye–hand coordination in adolescents with hemiparetic cerebral palsy (CP) and neurologically healthy controls. Using an object prehension and transport task, we addressed two hypotheses, motivated by the question whether early brain damage and the ensuing limitations of motor activity lead to general and/or effector-specific effects in visuomotor control of manual actions. We hypothesized that individuals with hemiparetic CP would more closely visually monitor actions with their affected hand, compared to both their less affected hand and to control participants without a sensorimotor impairment. A second, more speculative hypothesis was that, in relation to previously established deficits in prospective action control in individuals with hemiparetic CP, gaze patterns might be less anticipatory in general, also during actions performed with the less affected hand. Analysis of the gaze and hand movement data revealed the increased visual monitoring of participants with CP when using their affected hand at the beginning as well as during object transport. In contrast, no general deficit in anticipatory gaze control in the participants with hemiparetic CP could be observed. Collectively, these findings are the first to directly show that individuals with hemiparetic CP adapt eye–hand coordination to the specific constraints of the moving limb, presumably to compensate for sensorimotor deficits

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

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

Anticipatory planning deficits and task context effects in hemiparetic cerebral palsy

Contains fulltext : 56887.pdf (publisher's version ) (Closed access)Individuals with hemiparetic cerebral palsy (HCP) display deviant motor output, predominantly on one side of the body. The question pursued here is whether HCP participants have the ability to anticipate the forthcoming perceptual-motor demands of the goal of an action sequence. Such anticipatory planning was necessary to successfully perform the tasks that were studied. In experiment I, HCP participants had to grasp a hexagonal knob with their unimpaired hand by choosing one of five possible grasping patterns (free choice) and consequently rotate it 60°, 120°, or 180° Clockwise or Counterclockwise. HCP participants showed a large amount of task failures that were persistent throughout the task. These findings suggest a deficit in anticipatory planning. No such task failures were observed for the control group. In addition, the instructed degree of rotation had less effect on the selected grasping pattern for the HCP participants than for the controls. In experiment II, we investigated if HCP participants are prone to use context information that is directly available in the task, instead of planning the forthcoming perceptual-motor demands. To that aim, an arrow was inserted at one of the sides of the hexagon in a position that had no relevance for the action to be planned and executed. The location of this arrow significantly affected the grip selected in the HCP participants, but not in controls. Overall, the results suggest an anticipatory planning deficit in HCP participants that may be caused by an impairment at the motor imagery level. Consequently, as an alternative strategy, performance in HCP participants was predominantly based on information directly available in the task context;12 p