Investigating the role of visual and auditory search in reading and developmental dyslexia

Abstract

It has been suggested that auditory and visual sequential processing deficits contribute to phonological disorders in developmental dyslexia. As an alternative explanation to a phonological deficit as the proximal cause for reading disorders, the visual attention span hypothesis (VA Span) suggests that difficulties in processing visual elements simultaneously lead to dyslexia, regardless of the presence of a phonological disorder. In this study, we assessed whether deficits in processing simultaneously displayed visual or auditory elements is linked to dyslexia associated with a VA Span impairment. Sixteen children with developmental dyslexia and 16 age-matched skilled readers were assessed on visual and auditory search tasks. Participants were asked to detect a target presented simultaneously with 3, 9, or 15 distracters. In the visual modality, target detection was slower in the dyslexic children than in the control group on a “serial” search condition only: the intercepts (but not the slopes) of the search functions were higher in the dyslexic group than in the control group. In the auditory modality, although no group difference was observed, search performance was influenced by the number of distracters in the control group only. Within the dyslexic group, not only poor visual search (high reaction times and intercepts) but also low auditory search performance (d′) strongly correlated with poor irregular word reading accuracy. Moreover, both visual and auditory search performance was associated with the VA Span abilities of dyslexic participants but not with their phonological skills. The present data suggests that some visual mechanisms engaged in “serial” search contribute to reading and orthographic knowledge via VA Span skills regardless of phonological skills. The present results further open the question of the role of auditory simultaneous processing in reading as well as its link with VA Span skills.

What bilateral damage of the superior parietal lobes tells us about visual attention disorders in developmental dyslexia

“…She has been previously studied in visual search and shows a reduced visuo-attentional window specifically when she faces stimuli made by a combination of lines (Khan et al, 2016). This deficit in visual search after bilateral SPL damage is in line with the impaired search performance specific to « multifeatures shapes » combining separable features previously reported in poor readers (Casco & Prunetti, 1986) and with evidence for a visual search deficit in VA span impaired dyslexic children (Lallier et al, 2013).…”

“…In addition, Lassus-Sangosse et al (2008) showed that the VA span deficit is specific to parallel processing: the dyslexic participants who were impaired at processing the 5-consonant strings in parallel could report as many letters as the controls when the five consonants were displayed sequentially, one at a time, at the center of the computer screen (see also Valdois et al, 2011). There is also evidence that the deficit is not specific to horizontal displays but extends to circular presentations (Dubois et al, 2010), which could explain why poor VA span also affects performance in non-linear visual search tasks (Lallier et al, 2013) and why VA span is higher in individuals who play action video games than in non-players (Antzaka et al, 2017). Overall, the available behavioural data points towards a visuallydriven deficit that reflects a limitation in the amount of attentional resources available for multiple visual-element parallel processing.…”

Phonological processing deficits as a universal model for dyslexia: evidence from different orthographies

“…From the studies selected in the present review, it is clear that reading problems associated with dyslexia differ in regular orthographies such as Finnish (12) as compared to less regular orthographies such as French (13) . However, the underlying cause found in phonological processing skills holds for all levels of orthographic consistencies.…”

Visual motion and rapid auditory processing are solid endophenotypes of developmental dyslexia

“…, ; Lallier et al . ; Plaza & Cohen ; Vidyasagar & Pammer ). Converging evidence suggests that such attention deficits could specifically impair the sublexical processing in DD by affecting both the graphemic parsing (Cestnick & Coltheart ; Facoetti et al .…”

“…Notably, visual and auditory attention deficits have been repeatedly described in DD and have a causative role in DD (Franceschini et al , 2013Lallier et al 2013;Plaza & Cohen 2007;Vidyasagar & Pammer 2010). Converging evidence suggests that such attention deficits could specifically impair the sublexical processing in DD by affecting both the graphemic parsing (Cestnick & Coltheart 1999;Facoetti et al 2006Facoetti et al , 2010Hari & Renvall 2001) and the rapid engagement of attention (Facoetti et al 2005;Francis et al 2008;Gordon et al 1993;Renvall & Hari 2002;Toro et al 2005), which are crucial for the phonemic and graphemic perception and the segmentation of words.…”