title: Immaturity of Visual Fixations in Dyslexic Children.
abstract: To our knowledge, behavioral studies recording visual fixations abilities in dyslexic children are scarce. The object of this article is to explore further the visual fixation ability in dyslexics compared to chronological age-matched and reading age-matched non-dyslexic children. Fifty-five dyslexic children from 7 to 14 years old, 55 chronological age-matched non-dyslexic children and 55 reading age-matched non-dyslexic children participated to this study. Eye movements from both eyes were recorded horizontally and vertically by a video-oculography system (EyeBrain(®) T2). The fixation task consisted in fixating a white-filled circle appearing in the center of the screen for 30 s. Results showed that dyslexic children produced a significantly higher number of unwanted saccades than both groups of non-dyslexic children. Moreover, the number of unwanted saccades significantly decreased with age in both groups of non-dyslexic children, but not in dyslexics. Furthermore, dyslexics made more saccades during the last 15 s of fixation period with respect to both groups of non-dyslexic children. Such poor visual fixation capability in dyslexic children could be due to impaired attention abilities, as well as to an immaturity of the cortical areas controlling the fixation system.
authors.affiliation: UMR 1141, Institut National de la Santé et de la Recherche Médicale - Université Paris Diderot - Paris 7, Robert Debré Hospital Paris, France.
authors.forename: Aimé
authors.initials: A
authors.lastname: Tiadi
authors.affiliation: Child and Adolescent Psychiatry Department, Robert Debré Hospital Paris, France.
authors.forename: Christophe-Loïc
authors.initials: CL
authors.lastname: Gérard
authors.affiliation: Child and Adolescent Psychiatry Department, Robert Debré Hospital Paris, France.
authors.forename: Hugo
authors.initials: H
authors.lastname: Peyre
authors.affiliation: Ophthalmology Department, Robert Debré Hospital Paris, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Bui-Quoc
authors.affiliation: UMR 1141, Institut National de la Santé et de la Recherche Médicale - Université Paris Diderot - Paris 7, Robert Debré Hospital Paris, France.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Bucci
keywords: attention; children; dyslexia; eye movements; frontal eye field (FEF); immaturity; superior colliculus (SC); visual fixation