title: Cognitive-motor interference during fine and gross motor tasks in children with Developmental Coordination Disorder (DCD).
abstract: BACKGROUND
  While typically developing children produce relatively automatized postural control processes, children with DCD seem to exhibit an automatization deficit. Dual tasks with various cognitive loads seem to be an effective way to assess the automatic deficit hypothesis.
  
  
  OBJECTIVE
  The aims of the study were: (1) to examine the effect of a concurrent cognitive task on fine and gross motor tasks in children with DCD, and (2) to determine whether the effect varied with different difficulty levels of the concurrent task.
  
  
  METHODS
  We examined dual-task performance (Trail-Making-Test, Trail-Walking-Test) in 20 children with DCD and 39 typically developing children. Based on the idea of the Trail-Making-Test, participants walked along a fixed pathway, following a prescribed path, delineated by target markers of (1) increasing sequential numbers, and (2) increasing sequential numbers and letters. The motor and cognitive dual-task effects (DTE) were calculated for each task.
  
  
  RESULTS
  Regardless of the cognitive task, children with DCD performed equally well in fine and gross motor tasks, and were slower in the dual task conditions than under single task-conditions, compared with children without DCD. Increased cognitive task complexity resulted in slow trail walking as well as slower trail tracing. The motor interference for the gross motor tasks was least for the simplest conditions and greatest for the complex conditions and was more pronounced in children with DCD. Cognitive interference was low irrespective of the motor task.
  
  
  CONCLUSIONS
  Children with DCD show a different approach to allocation of cognitive resources, and have difficulties making motor skills automatic. The latter notion is consistent with impaired cerebellar function and the "automatization deficit hypothesis", suggesting that any deficit in the automatization process will appear if conscious monitoring of the motor skill is made more difficult by integrating another task requiring attentional resources.
authors.affiliation: Department of Sport and Exercise Science, University of Stuttgart, Germany. Electronic address: nadja.schott@inspo.uni-stuttgart.de.
authors.forename: Nadja
authors.initials: N
authors.lastname: Schott
authors.affiliation: Department of Sport and Exercise Science, University of Stuttgart, Germany.
authors.forename: Inaam
authors.initials: I
authors.lastname: El-Rajab
authors.affiliation: Department of Sport and Exercise Science, University of Stuttgart, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Klotzbier
mesh_terms: D016022:Case-Control Studies; D002648:Child; D003071:Cognition; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term; D009048:Motor Skills; D019957:Motor Skills Disorders / Q000503:physiopathology / Q000523:psychology*; D009483:Neuropsychological Tests; D013647:Task Performance and Analysis; D014145:Trail Making Test; D016138:Walking
keywords: Allocentric vs. egocentric; Automatization deficit hypothesis; Dual task effects; Executive attention network; Internal modeling deficit; Peripersonal vs extra-personal; Trail-Walking-Test; Visuo-spatial working memory