Deficits in executed and imagined aiming performance in brain-injured children.

Motor disorders are a frequent consequence of acquired brain injury (ABI) in children and much effort is currently invested in alleviating these deficits. The aim of the present study was to test motor imagery (MI) capabilities in children with ABI (n=25) and an age- and gender-matched control group (n=25). A computerized Virtual Radial Fitts Task (VRFT) was used to investigate the speed-accuracy trade-offs (or Fitts' law) that occur as target size is varied for both executed and imagined performance. In the control group, the speed for accuracy trade-off for both executed and imagined performance conformed to Fitts' law. In the ABI group, only executed movements conformed to Fitts' law. These findings suggest that children with ABI show an inferior ability to imagine the time needed to complete goal-directed movements with differential difficulty levels.