Nguyen-Kolbe-2021

Authors: Bao N. Nguyen, Scott C. Kolbe, Ashika Verghese, Christine Nearchou, Allison M. McKendrick, Gary F. Egan, Trichur R. Vidyasagar.

Article: Visual search efficiency and functional visual cortical size in children with and without dyslexia.

Publication: Neuropsychologia (Elsevier). 107819 2021 | DOI: 10.1016/j.neuropsychologia.2021.10781

Highlights

Visual search efficiency correlates with reading ability in children.
Left/right visual cortical size asymmetry relates to reading ability in children.
Our findings suggest a deficit in visuospatial attention in dyslexia.

Abstract:

Dyslexia is characterised by poor reading ability. Its aetiology is probably multifactorial, with abnormal visual processing playing an important role. Among adults with normal reading ability, there is a larger representation of central visual field in the primary visual cortex (V1) in those with more efficient visuospatial attention. In this study, we tested the hypothesis that poor reading ability in school-aged children (17 children with dyslexia, 14 control children with normal reading ability) is associated with deficits in visuospatial attention using a visual search task. We corroborated the psychophysical findings with neuroimaging, by measuring the functional size of V1 in response to a central 12° visual stimulus. Consistent with other literature, visual search was impaired and less efficient in the dyslexic children, particularly with more distractor elements in the search array (p=0.04). We also found atypical interhemispheric asymmetry in functional V1 size in the dyslexia group (p=0.02). Reading impaired children showed poorer visual search efficiency (p=0.01), needing more time per unit distractor (higher ms/item). Reading ability was also correlated with V1 size asymmetry (p=0.03), such that poorer readers showed less left hemisphere bias relative to the right hemisphere. Our findings support the view that dyslexic children have abnormal visuospatial attention and interhemispheric V1 asymmetry, relative to chronological age-matched peers, and that these factors may contribute to inter-individual variation in reading performance in children.

Tagged as: asymmetry, fMRI, and visual attention span

Citation:

Bao N. Nguyen, Scott C. Kolbe, Ashika Verghese, Christine Nearchou, Allison M. McKendrick, Gary F. Egan, Trichur R. Vidyasagar,
Visual search efficiency and functional visual cortical size in children with and without dyslexia,
Neuropsychologia, 2021, 107819,
https://doi.org/10.1016/j.neuropsychologia.2021.10781

Leave a public question or comment:

If you need personal help or assistance please use our contact forms instead.


All comments are moderated. Comments that are not relevant to the page topic or which contain identifiable personal information will not be published.


Your email address will not be published. Required fields are marked *