title: Comparison of accuracy and efficiency of directed scanning and group-item scanning for augmentative communication selection techniques with typically developing preschoolers.
abstract: OBJECTIVE
  Directed scanning and group-item scanning both represent options for increased scanning efficiency. This investigation compared accuracy and speed of selection with preschoolers using each scanning method. The study's purpose was to describe performance characteristics of typically developing children and to provide a reliable assessment protocol to evaluate scanning skills.
  
  
  METHODS
  Investigators examined within-participant performance on an identity matching-to-sample task using directed and group-item scanning with 13 typically developing preschoolers. Children selected line-drawn symbols from a 36-symbol display configured for each scanning method.
  
  
  RESULTS
  Children were more accurate using directed than group-item scanning. They required a greater number of cursor movements to accurately select symbols with group-item than with directed scanning; however, no differences in actual selection time were apparent. Further analyses comparing performance using group-item scanning for selections requiring either a low or a high number of cursor movements revealed no differences in children's accuracy or efficiency.
  
  
  CONCLUSIONS
  Children were more accurate using directed scanning to select target symbols. However, directed scanning did not afford a relative advantage in children's selection efficiency compared with group-item scanning. Performance using group-item scanning does not appear to be affected by requisite cursor movements for selection. Limitations and educational implications are discussed.
authors.affiliation: University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Dropik
authors.forename: Joe
authors.initials: J
authors.lastname: Reichle
mesh_terms: D002675:Child, Preschool; D003142:Communication; D005260:Female; D006801:Humans; D008297:Male; D013561:Symbolism; D013663:Teaching / Q000379:methods / Q000592:standards*; D013813:Therapy, Computer-Assisted