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Thursday, May 15, 2008
Champagne Terrace/Bordeaux (Novotel London West)
Background: Impairment of movement skills is a well-known feature of autism and deficits in motor cognition may possibly be related to later impairment in social cognition.
One hypothesis is that the feedback loop that serves to develop motor control in the reach-to-grasp action is important for the development of theory-of-mind.
Objectives: To explore feedback sensitivity during a repetitive incrementally modified task.
Methods: In a motor decision-making task, participants (68 adults, 74 control children and 20 children with autism) were required to reach-and-grasp a 4cm length of doweling positioned at a variable angle in the transverse plane and use a pincer grip to grasp the ends of the dowel. The doweling was positioned at different orientations either randomly or systematically (orientation changed by 30° every five reaches either clockwise or counter-clockwise). This required a variable rotation of the lower arm, either clockwise or anticlockwise. In one group of participants, the angle changed randomly. In another group it changed incrementally. Participants could choose either to rotate the lower arm to gain maximum economy of movement or to use the same direction of lower arm movement as used in the previous trial.
Results: When the angle changed incrementally, control participants continued to select the previous direction of movement, even when the opposite direction would have been more economical and comfortable, as indicated by movements selected during random trials. Participants with autism showed a reduced influence of prior movement history. Thus, movements selected during trials when the angle changed incrementally were more similar to those choices made when the angle changed randomly.
Conclusions: Among control participants, successful prior actions bias decision-making to favour repetition of movement strategies in subsequent tasks. In autism, this influence appears to be significantly weaker, perhaps resulting in a diminished capacity for motor learning that could impact upon social cognitive development.
One hypothesis is that the feedback loop that serves to develop motor control in the reach-to-grasp action is important for the development of theory-of-mind.
Objectives: To explore feedback sensitivity during a repetitive incrementally modified task.
Methods: In a motor decision-making task, participants (68 adults, 74 control children and 20 children with autism) were required to reach-and-grasp a 4cm length of doweling positioned at a variable angle in the transverse plane and use a pincer grip to grasp the ends of the dowel. The doweling was positioned at different orientations either randomly or systematically (orientation changed by 30° every five reaches either clockwise or counter-clockwise). This required a variable rotation of the lower arm, either clockwise or anticlockwise. In one group of participants, the angle changed randomly. In another group it changed incrementally. Participants could choose either to rotate the lower arm to gain maximum economy of movement or to use the same direction of lower arm movement as used in the previous trial.
Results: When the angle changed incrementally, control participants continued to select the previous direction of movement, even when the opposite direction would have been more economical and comfortable, as indicated by movements selected during random trials. Participants with autism showed a reduced influence of prior movement history. Thus, movements selected during trials when the angle changed incrementally were more similar to those choices made when the angle changed randomly.
Conclusions: Among control participants, successful prior actions bias decision-making to favour repetition of movement strategies in subsequent tasks. In autism, this influence appears to be significantly weaker, perhaps resulting in a diminished capacity for motor learning that could impact upon social cognitive development.