title: Abnormal frontal theta oscillations underlie the cognitive flexibility deficits in children with high-functioning autism spectrum disorders.
abstract: OBJECTIVE
  Deficits in cognitive flexibility have been suggested to underlie the repetitive and stereotyped behavior in individuals with autism spectrum disorders (ASD). Because cognitive flexibility is primarily mediated by the frontal lobe, where structural and functional abnormalities have been extensively found in these individuals, it is conceivable that their deficits in cognitive flexibility are related to abnormal activations of the frontal lobe. The present study investigates cognitive flexibility and its underlying neurophysiological activities as indicated by theta oscillations in children with ASD.
  
  
  METHODS
  Twenty-five children with high-functioning ASD and 25 IQ- and age-matched typically developing (TD) children were subjected to neuropsychological assessments on cognitive flexibility and electroencephalography recordings.
  
  
  RESULTS
  The children with ASD performed significantly worse than the TD children across the tasks of cognitive flexibility, including the modified Wisconsin Card Sorting Test (WCST). These children also demonstrated a reduced increase of the theta power localized in multiple brain regions, including various sectors of the frontal lobe at the late stage (i.e., 600 ms-900 ms poststimulus interval) but not the early stage (i.e., 250 ms-550 ms poststimulus interval) of the performance of the modified WCST. The suppressed late frontal theta activities were further shown to be significantly correlated with a poorer performance on the cognitive flexibility measures.
  
  
  CONCLUSIONS
  Our findings suggest that abnormal activations of multiple cortical regions, especially the frontal lobe, form the neural basis of the cognitive flexibility deficits in children with ASD. In addition, we found an EEG marker of cognitive flexibility which could be used to monitor treatment outcomes objectively.
authors.affiliation: Neuropsychology Laboratory, Department of Psychology, The Chinese University of Hong Kong.
authors.forename: Michael K
authors.identifier: 0000-0001-6699-6080
authors.initials: MK
authors.lastname: Yeung
authors.affiliation: Department of Special Education and Counselling, The Hong Kong Institute of Education.
authors.forename: Yvonne M Y
authors.identifier: 0000-0002-9534-6834
authors.initials: YMY
authors.lastname: Han
authors.affiliation: Neuropsychology Laboratory, Department of Psychology, The Chinese University of Hong Kong.
authors.forename: Sophia L
authors.initials: SL
authors.lastname: Sze
authors.affiliation: Neuropsychology Laboratory, Department of Psychology, The Chinese University of Hong Kong.
authors.forename: Agnes S
authors.initials: AS
authors.lastname: Chan
mesh_terms: D000293:Adolescent; D000067877:Autism Spectrum Disorder / Q000503:physiopathology* / Q000523:psychology*; D002648:Child; D003072:Cognition Disorders / Q000503:physiopathology* / Q000523:psychology*; D004569:Electroencephalography; D005071:Evoked Potentials; D056344:Executive Function; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D013826:Theta Rhythm; D014888:Wechsler Scales