title: Impaired multiple object tracking in children with chromosome 22q11.2 deletion syndrome.
abstract: BACKGROUND
  Chromosome 22q11.2 Deletion Syndrome (22q11.2DS) occurs in approximately 1:4,000 live births with a complex and variable presentation that includes medical, socioemotional and psychological symptoms with intellectual impairment. Cognitive impairments in spatiotemporal and visuospatial attention have also been reported. However, maintenance of selective attention to dynamic and interacting objects has not been systematically investigated in children with 22q11.2DS.
  
  
  METHODS
  We used a multiple object tracking task to assay capacity and resolution performance of children with 22q11.2DS aged 7 to 14 years versus age-matched typically developing (TD) peers.
  
  
  RESULTS
  Children with 22q11.2DS but not TD children demonstrated impaired performance when task demands increased due to an increase in the number of targets presented, but not from an increase in object speed. Task performance in children with 22q11.2DS was also unrelated to intelligence or measures of attention deficit hyperactivity disorder.
  
  
  CONCLUSIONS
  These findings suggest that children with 22q11.2DS may be particularly susceptible to dynamic crowding of objects with increasing cognitive demands related to monitoring multiple targets reflecting a reduced acuity in spatiotemporal cognitive representation.
authors.affiliation: Department of Psychiatry and Behavioral Sciences and the Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Medical Center, 2825 50th Street, Sacramento, CA 95817, USA. tjsimon@ucdavis.edu.
authors.forename: Margarita H
authors.initials: MH
authors.lastname: Cabaral
authors.forename: Elliott A
authors.initials: EA
authors.lastname: Beaton
authors.forename: Joel
authors.initials: J
authors.lastname: Stoddard
authors.forename: Tony J
authors.initials: TJ
authors.lastname: Simon