A Test of Motor (Not Executive) Planning in Developmental Coordination Disorder and Autism

Lisa M. van Swieten, Elsje van Bergen, Justin H. G. Williams, Andrew D. Wilson, Mandy S. Plumb, Samuel W. Kent, Mark A. Mon-Williams

Research output: Contribution to journalArticle

74 Citations (Scopus)

Abstract

Grip selection tasks have been used to test "planning" in both autism and developmental coordination disorder (DCD). We differentiate between motor and executive planning and present a modified motor planning task. Participants grasped a cylinder in 1 of 2 orientations before turning it clockwise or anticlockwise. The rotation resulted in a comfortable final posture at the cost of a harder initial reaching action on 50% of trials. We hypothesized that grip selection would be dominated by motoric developmental status. Adults were always biased towards a comfortable end-state with their dominant hand, but occasionally ended uncomfortably with their nondominant hand. Most 9- to 14-year-olds with and without autism also showed this "end-state comfort" bias but only 50% of 5- to 8-year-olds. In contrast, children with DCD were biased towards selecting the simplest initial movement. Our results are best understood in terms of motor planning, with selection of an easier initial grip resulting from poor reach-to-grasp control rather than an executive planning deficit. The absence of differences between autism and controls may reflect the low demand this particular task places on executive planning.

Original languageEnglish
Pages (from-to)493-499
Number of pages7
JournalJournal of Experimental Psychology: Human Perception and Performance
Volume36
Issue number2
DOIs
Publication statusPublished - Apr 2010

Keywords

  • motor planning
  • grip selection
  • bias
  • prehension
  • coordination
  • autism
  • DCD
  • children
  • dysfunction
  • movements

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