Impaired Spatial Category Representations in Williams Syndrome; an Investigation of the Mechanistic Contributions of Non-verbal Cognition and Spatial Language Performance.

Emily K Farran,Lauren Atkinson,Hannah Broadbent

doi:10.3389/fpsyg.2016.01868

Emily K Farran, Lauren Atkinson + Show 1 more

Open Access

https://doi.org/10.3389/fpsyg.2016.01868

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Abstract

The aims of this study were to: provide a precise characterisation of spatial category representations in Williams syndrome (WS); to determine the nature of the mechanistic contributions from spatial language performance and non-verbal cognition to spatial category representations in WS; and to explore the stability of spatial category representations in WS using error analysis. Spatial category representation was assessed across nine spatial categories (In, On, Under, In Front, Behind, Above, Below, Left, and Right) using an odd-one-out task. The performance of individuals with WS (N = 24; 12;00 years;months to 30;07 years;months) was compared to data from typically developing children aged four to 7 years (N = 75), published in Farran and Atkinson (2016). The WS group performed at the level of typical 4- and 5-year-olds. Despite this low level of ability, they demonstrated typical variation in their representation of easier to harder spatial categories, in line with the spatial category representation model (Farran and Atkinson, 2016). Error analysis of broad category understanding (i.e., category understanding which includes non-prototypical category members), however, showed that errors reflected fewer guess responses than expected by chance in the WS group only, which could suggest strategic responding in this group. Developmental trajectory analyses demonstrated a significant contributing influence of both non-verbal mental age and spatial language ability in the TD group. For the WS group, non-verbal mental age significantly contributed to spatial category representations, whilst the contributing influence of spatial language ability was marginally significant. With reference to level of ability, spatial category representations in the WS group were consistently lower than would be expected for non-verbal mental age, but on a par with their (low) spatial language mental age. Spatial category representations in WS are discussed with reference to their contribution to the hallmark deficit in spatial construction and drawing abilities in WS.

Highlights

Williams syndrome (WS) is a neurodevelopmental disorder with a prevalence of one in 7,500 to one in 20,000 (Morris and Mervis, 1999; Strømme et al, 2002)
Three ANOVAs were carried out to compare the performance of the WS group to that of the four typically developing (TD) groups, for each dependent variable
Of interest here are post hoc Tukey tests comparing the performance of the WS group against that of each TD group

Summary

Introduction

Williams syndrome (WS) is a neurodevelopmental disorder with a prevalence of one in 7,500 to one in 20,000 (Morris and Mervis, 1999; Strømme et al, 2002). A profound deficit in performance on visuo-spatial construction tasks, such as the Wechsler Block Design task (e.g., Wechsler, 1992), is considered a hallmark of WS (Mervis et al, 1999) Performance on this task does not usually develop beyond the level of a TD 4-year-old (Farran and Formby, 2012). Performance on visuo-spatial construction and drawing tasks in WS suggests an underlying deficit in perceiving and producing spatial relationships. People with WS make fewer checks of their part-finished solutions during block construction and drawing tasks than do TD controls (Hoffman et al, 2003; Hudson and Farran, 2013) This suggests attenuated attention to, or a lack of ability to adhere to, the spatial relationships of the model image

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