Large-scale visuospatial cognition in Williams syndrome and typically developing children

• Main Author: Broadbent, Hannah Jayne
• Published: University College London (University of London) 2015
• Subjects: 618.92; Psychology and Human Development
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.646155

Williams syndrome (WS) is a neurodevelopmental disorder of known genetic origin. A characteristically uneven cognitive profile in WS, with a marked contrast between poor small-scale visuospatial ability relative to stronger verbal ability, is well documented. Recent findings demonstrate visuospatial deficits pervade to large-scale navigation abilities in this group. Experimental studies presented in this thesis investigate the nature of large-scale visuospatial impairment in WS at the level of behaviour, as well as the genetic contributions to the WS visuospatial profile. As an important basis on which to understand the nature of atypical development in WS, the thesis also examines the development of large-scale spatial cognition in typicallydeveloping (TD) children. Developmental changes in the use of different spatial frames of reference to mentally represent spatial information both on small-scale tasks and during navigation in large-scale virtual environments were observed in TD children between 6 and 8 years of age, with an adult-like pattern of performance acquired between 8 and 10 years. The findings in TD children provide novel insight into the nature of processes underlying the use of different aspects of spatial knowledge for navigation. In WS, impairments in both egocentric and allocentric spatial reference frames result in severe detriment to spatial processing at both small- and large scales. However, the data suggest that not all aspects of large-scale spatial knowledge are equally impaired in WS, highlighting the multifaceted nature of visuospatial cognition, and extending our understanding of the profile of relative strengths and weaknesses within the visuospatial cognitive domain in this disorder. An examination of the genetic contribution to the WS visuospatial phenotype from two individuals with partial WS genetic deletions further highlights the diverse nature of visuospatial cognition. These findings provide insight both into the dynamic development of visuospatial cognition in typical development, and the atypical visuospatial phenotype in WS.