The reliability of pseudoneglect is task dependent

A.G Mitchell,J.M Harris,S.E Benstock,J.M Ales

doi:10.1016/j.neuropsychologia.2020.107618

A.G Mitchell, J.M Harris + Show 2 more

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https://doi.org/10.1016/j.neuropsychologia.2020.107618

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Abstract

Bisection tasks that require individuals to identify the midpoint of a line are often used to assess the presence of biases to spatial attention in both healthy and patient populations. These tasks have helped to uncover a phenomenon called pseudoneglect, a bias towards the left-side of space in healthy individuals. First identified in the tactile domain, pseudoneglect has been subsequently demonstrated in other sensory modalities such as vision. Despite this, the specific reliability of pseudoneglect within individuals across tasks and time has been investigated very little. In this study, we investigated the reliability of response bias within individuals across four separate testing sessions and during three line bisection tasks: landmark, line bisection and tactile rod bisection. Strong reliability was expected within individuals across task and session. Pseudoneglect was found when response bias was averaged across all tasks, for the entire sample. However, individual data showed biases to both left and right, with some participants showing no clear bias, demonstrating individual differences in bias. Significant, cross-session within-individual reliability was found for the landmark and tactile rod bisection tasks respectively, but no significant reliability was observed for the line bisection task. These results highlight the inconsistent nature of pseudoneglect within individuals, particularly across sensory modality. They also provide strong support for the use of the landmark task as the most reliable measure of pseudoneglect.

Highlights

Spatial neglect presents as an extreme preference towards the right side of space after a stroke to the right-hemisphere (Halligan et al, 1991)
The essence of this work was to further our understanding of the implicit spatial biases that are present among the general population and found evidence towards individual variation in pseudoneglect
A promising follow-up from this study would be to investi gate the spread of individual differences in response bias within the general population, to gain insight into the expected distribution of bias as well as the overall prevalence of pseudoneglect

Summary

Introduction

Spatial neglect presents as an extreme preference towards the right side of space after a stroke to the right-hemisphere (Halligan et al, 1991). Neurotypical individuals typically transect the line further to the left of its true midpoint (Benwell et al, 2014; Learmonth et al, 2015; Manning et al, 1990; McCourt and Olafson, 1997; Nicholls and Roberts, 2002) This phenomenon is known as pseudoneglect and has been repeatedly identified among the general population (Brooks et al, 2016; Friedrich et al, 2018; Jewell and McCourt, 2000) and is thought to be a result of a slight, lateralised bias to spatial attention (Heilman and Van Den Abell, 1979; Kinsbourne, 1970). Understanding the prevalence and reliability of pseudoneglect in the healthy population can potentially improve our understanding of human perception and attention

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