title: Peripersonal spatial attention in children with spina bifida: associations between horizontal and vertical line bisection and congenital malformations of the corpus callosum, midbrain, and posterior cortex.
abstract: Horizontal and vertical line bisection was studied in 129 children and adolescents between 8 and 19 years of age, one group (n=32) of typically developing controls and one group (n=97) with spina bifida (SBM), a neurodevelopmental disorder associated with dysmorphology of the corpus callosum, posterior cortex, and midbrain. For each participant, structural brain MRIs were analyzed qualitatively to identify beaking of the midbrain tectum and corpus callosum agenesis and hypoplasia and quantitatively by segmentation and volumetric analyses of regional cortical white and gray matter. Each group showed the line length effect, whereby greater estimation errors are made with longer lines. The group with SBM differed from controls in terms of both accuracy and variability of line bisection. Children with SBM showed pseudoneglect, attending more than controls to left hemispace. The extent of rightward bisection bias was unrelated to right posterior brain volumes, although an intact corpus callosum during development moderated and normalized the exaggerated leftward line bisection bias. More children with SBM than controls attended to inferior hemispace. A normal midbrain and greater posterior cortex volume during development moderated and normalized the downward bias. Children with SBM showed more intra-subject variability than controls. Line bisection in children with SBM reflects three deficits: an exaggerated attentional bias to left hemispace, an abnormal attentional bias to inferior hemispace; and a larger zone of subjective uncertainty in bisection judgments.
authors.affiliation: Brain and Behaviour Program, Department of Psychology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ont., Canada M5G 1X8. maureen.dennis@sickkids.ca
authors.forename: Maureen
authors.initials: M
authors.lastname: Dennis
authors.forename: Kim
authors.initials: K
authors.lastname: Edelstein
authors.forename: Jon
authors.initials: J
authors.lastname: Frederick
authors.forename: Kim
authors.initials: K
authors.lastname: Copeland
authors.forename: David
authors.initials: D
authors.lastname: Francis
authors.forename: Susan E
authors.initials: SE
authors.lastname: Blaser
authors.forename: Larry A
authors.initials: LA
authors.lastname: Kramer
authors.forename: James M
authors.initials: JM
authors.lastname: Drake
authors.forename: Michael
authors.initials: M
authors.lastname: Brandt
authors.forename: Ross
authors.initials: R
authors.lastname: Hetherington
authors.forename: Jack M
authors.initials: JM
authors.lastname: Fletcher
mesh_terms: D000293:Adolescent; D000328:Adult; D061085:Agenesis of Corpus Callosum; D001288:Attention / Q000502:physiology*; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000473:pathology / Q000503:physiopathology; D002648:Child; D003337:Corpus Callosum / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008636:Mesencephalon / Q000002:abnormalities* / Q000473:pathology / Q000503:physiopathology; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011597:Psychomotor Performance / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D016135:Spinal Dysraphism / Q000503:physiopathology*