title: Gap Effect Abnormalities during a Visually Guided Pro-Saccade Task in Children with Attention Deficit Hyperactivity Disorder.
abstract: Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that starts in early childhood and has a comprehensive impact on psychosocial activity and education as well as general health across the lifespan. Despite its prevalence, the current diagnostic criteria for ADHD are debated. Saccadic eye movements are easy to quantify and may be a quantitative biomarker for a wide variety of neurological and psychiatric disorders, including ADHD. The goal of this study was to examine whether children with ADHD exhibit abnormalities during a visually guided pro-saccadic eye-movement and to clarify the neurophysiological mechanisms associated with their behavioral impairments. Thirty-seven children with ADHD (aged 5-11 years) and 88 typically developing (TD) children (aged 5-11 years) were asked to perform a simple saccadic eye-movement task in which step and gap conditions were randomly interleaved. We evaluated the gap effect, which is the difference in the reaction time between the two conditions. Children with ADHD had a significantly longer reaction time than TD children (p < 0.01) and the gap effect was markedly attenuated (p < 0.01). These results suggest that the measurement of saccadic eye movements may provide a novel method for evaluating the behavioral symptoms and clinical features of ADHD, and that the gap effect is a potential biomarker for the diagnosis of ADHD in early childhood.
authors.affiliation: Department of Social and Environmental Medicine, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Matsuo
authors.affiliation: Department of Biomedical and Molecular Sciences, Queens University, Kingston, Ontario, Canada.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, Suita, Osaka, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Taniike
authors.affiliation: Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, Suita, Osaka, Japan.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Mohri
authors.affiliation: Department of Electrical Engineering and Computer Sciences, Graduate School of Engineering, University of Hyogo, Shosha, Himeji, Hyogo, Japan.
authors.forename: Syoji
authors.initials: S
authors.lastname: Kobashi
authors.affiliation: Department of Neuroscience, Mayo Clinic Florida, Jacksonville, Florida, United States of America.
authors.forename: Masaya
authors.initials: M
authors.lastname: Tachibana
authors.affiliation: Visual Neuroscience Laboratory, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan; Center for Information and Neural Networks, National Institute of Information and Communications Technology and Osaka University, Suita, Osaka, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Department of Social and Environmental Medicine, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Kitamura
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D015415:Biomarkers / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D012438:Saccades / Q000502:physiology*
chemical_list: D015415:Biomarkers