title: Altered sense of Agency in children with spastic cerebral palsy.
abstract: BACKGROUND
  Children diagnosed with spastic Cerebral Palsy (CP) often show perceptual and cognitive problems, which may contribute to their functional deficit. Here we investigated if altered ability to determine whether an observed movement is performed by themselves (sense of agency) contributes to the motor deficit in children with CP.
  
  
  METHODS
  Three groups; 1) CP children, 2) healthy peers, and 3) healthy adults produced straight drawing movements on a pen-tablet which was not visible for the subjects. The produced movement was presented as a virtual moving object on a computer screen. Subjects had to evaluate after each trial whether the movement of the object on the computer screen was generated by themselves or by a computer program which randomly manipulated the visual feedback by angling the trajectories 0, 5, 10, 15, 20 degrees away from target.
  
  
  RESULTS
  Healthy adults executed the movements in 310 seconds, whereas healthy children and especially CP children were significantly slower (p < 0.002) (on average 456 seconds and 543 seconds respectively). There was also a statistical difference between the healthy and age matched CP children (p = 0.037). When the trajectory of the object generated by the computer corresponded to the subject's own movements all three groups reported that they were responsible for the movement of the object. When the trajectory of the object deviated by more than 10 degrees from target, healthy adults and children more frequently than CP children reported that the computer was responsible for the movement of the object. CP children consequently also attempted to compensate more frequently from the perturbation generated by the computer.
  
  
  CONCLUSIONS
  We conclude that CP children have a reduced ability to determine whether movement of a virtual moving object is caused by themselves or an external source. We suggest that this may be related to a poor integration of their intention of movement with visual and proprioceptive information about the performed movement and that altered sense of agency may be an important functional problem in children with CP.
authors: Department of Exercise and Sport Sciences, Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark. aninari@sund.ku.dk
authors: Anina
authors: A
authors: Ritterband-Rosenbaum
authors: Mark S
authors: MS
authors: Christensen
authors: Mette
authors: M
authors: Kliim-Due
authors: Line Z
authors: LZ
authors: Petersen
authors: Betina
authors: B
authors: Rasmussen
authors: Jens B
authors: JB
authors: Nielsen
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D002547:Cerebral Palsy / Q000150:complications* / Q000503:physiopathology*; D002648:Child; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology; D005260:Female; D006801:Humans; D033182:Intention; D008297:Male; D009068:Movement / Q000502:physiology*; D009069:Movement Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D011434:Proprioception / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D012016:Reference Values; D055815:Young Adult