title: Deficits in executive functions among youths with autism spectrum disorders: an age-stratified analysis.
abstract: Impaired executive function (EF) is suggested to be one of the core features in individuals with autism spectrum disorders (ASD); however, little is known about whether the extent of worse EF in ASD than typically developing (TD) controls is age-dependent. We used age-stratified analysis to reveal this issue.
  
  
  
  We assessed 111 youths with ASD (aged 12.5 ± 2.8 years, male 94.6%) and 114 age-, and sex-matched TD controls with Digit Span and four EF tasks of the Cambridge Neuropsychological Test Automated Battery (CANTAB): Spatial Span (SSP), Spatial Working Memory (SWM), Stockings of Cambridge (SOC), and Intradimensional/Extradimensional Shift Test (I/ED).
  
  
  
  Compared to TD controls, youths with ASD performed poorer on the Digit Span, SWM, SOC, and I/ED tasks. The performance of all the tasks improved with age for both groups. Age-stratified analyses were conducted due to significant age × group interactions in visuospatial planning (SOC) and set-shifting (I/ED) and showed that poorer performance on these two tasks in ASD than TD controls was found only in the child (aged 8-12 years) rather than the adolescent (aged 13-18 years) group. By contrast, youths with ASD had impaired working memory, regardless of age. The increased magnitude of group difference in visuospatial planning (SOC) with increased task demands differed between the two age groups but no age moderating effect on spatial working memory.
  
  
  
  Our findings support deficits in visuospatial working memory and planning in youths with ASD; however, worse performance in set-shifting may only be demonstrated in children with ASD.
authors.affiliation: Department of Psychiatry,National Taiwan University Hospital & College of Medicine,Taipei,Taiwan.
authors.forename: S-F
authors.initials: SF
authors.lastname: Chen
authors.affiliation: Department of Psychiatry,National Taiwan University Hospital & College of Medicine,Taipei,Taiwan.
authors.forename: Y-L
authors.initials: YL
authors.lastname: Chien
authors.affiliation: Department of Psychiatry,National Taiwan University Hospital & College of Medicine,Taipei,Taiwan.
authors.forename: C-T
authors.initials: CT
authors.lastname: Wu
authors.affiliation: Department of Psychiatry,National Taiwan University Hospital & College of Medicine,Taipei,Taiwan.
authors.forename: C-Y
authors.initials: CY
authors.lastname: Shang
authors.affiliation: Department of Psychiatry,Chang Gung Memorial Hospital-Linkou,Taoyuan,Taiwan.
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Wu
authors.affiliation: Department of Psychiatry,National Taiwan University Hospital & College of Medicine,Taipei,Taiwan.
authors.forename: S S
authors.initials: SS
authors.lastname: Gau
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000067877:Autism Spectrum Disorder / Q000503:physiopathology / Q000523:psychology*; D016022:Case-Control Studies; D002648:Child; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests
keywords: Age effect; autism spectrum disorders; executive functions