TY - JOUR

T1 - Fractionating the multi-character processing deficit in developmental dyslexia

T2 - Evidence from two case studies

AU - Dubois, Matthieu

AU - Kyllingsbæk, Søren

AU - Prado, Chloé

AU - Musca, Serban C

AU - Peiffer, Elsa

AU - Lassus-Sangosse, Delphine

AU - Valdois, Sylviane

N1 - Copyright (c) 2010. Published by Elsevier Srl.

PY - 2010/6/1

Y1 - 2010/6/1

N2 - While there is growing evidence that some dyslexic children suffer from a deficit in simultaneously processing multiple visually displayed elements, the precise nature of the deficit remains largely unclear. The aim of the present study is to investigate possible cognitive impairments at the source of this deficit in dyslexic children. The visual processing of simultaneously presented letters was thus thoroughly assessed in two dyslexic children by means of a task that requires the report of briefly presented multi-letters arrays. A computational model of the attentional involvement in multi-object recognition (Bundesen, 1990, 1998) served as framework for analysing the data. By combining psychophysical measurements with computational modelling, we demonstrated that the visual processing deficit of simultaneously displayed letters, observed in the two dyslexic individuals reported in the current study, stems from at least two distinct cognitive sources: a reduction of the rate of-letter-information uptake, and a limitation of the maximal number of elements extracted from a brief visual display and stored in visual short-term memory. Possible relations between these impairments and learning to read proficiently are discussed.

AB - While there is growing evidence that some dyslexic children suffer from a deficit in simultaneously processing multiple visually displayed elements, the precise nature of the deficit remains largely unclear. The aim of the present study is to investigate possible cognitive impairments at the source of this deficit in dyslexic children. The visual processing of simultaneously presented letters was thus thoroughly assessed in two dyslexic children by means of a task that requires the report of briefly presented multi-letters arrays. A computational model of the attentional involvement in multi-object recognition (Bundesen, 1990, 1998) served as framework for analysing the data. By combining psychophysical measurements with computational modelling, we demonstrated that the visual processing deficit of simultaneously displayed letters, observed in the two dyslexic individuals reported in the current study, stems from at least two distinct cognitive sources: a reduction of the rate of-letter-information uptake, and a limitation of the maximal number of elements extracted from a brief visual display and stored in visual short-term memory. Possible relations between these impairments and learning to read proficiently are discussed.

KW - Attention

KW - Child

KW - Cognition Disorders

KW - Computer Simulation

KW - Dyslexia

KW - Female

KW - Humans

KW - Language Tests

KW - Male

KW - Memory, Short-Term

KW - Models, Neurological

KW - Neuropsychological Tests

KW - Photic Stimulation

KW - Psychophysics

KW - Recognition (Psychology)

KW - Visual Perception

U2 - 10.1016/j.cortex.2009.11.002

DO - 10.1016/j.cortex.2009.11.002

M3 - Journal article

C2 - 20116054

VL - 46

SP - 717

EP - 738

JO - Cortex

JF - Cortex

SN - 0010-9452

IS - 6

ER -