Problems with visual statistical learning in developmental dyslexia

Abstract

Previous research shows that dyslexic readers are impaired in their recognition of faces and other complex objects, and show hypoactivation in ventral visual stream regions that support word and object recognition. Responses of these brain regions are shaped by visual statistical learning. If such learning is compromised, people should be less sensitive to statistically likely feature combinations in words and other objects, and impaired visual word and object recognition should be expected. We therefore tested whether people with dyslexia showed diminished capability for visual statistical learning. Matched dyslexic and typical readers participated in tests of visual statistical learning of pairs of novel shapes that frequently appeared together. Dyslexic readers on average recognized fewer pairs than typical readers, indicating some problems with visual statistical learning. These group differences were not accounted for by differences in intelligence, ability to remember individual shapes, or spatial attention paid to the stimuli, but other attentional problems could play a mediating role. Deficiencies in visual statistical learning may in some cases prevent appropriate experience-driven shaping of neuronal responses in the ventral visual stream, hampering visual word and object recognition.

Are children with developmental dyslexia all the same? A cluster analysis with more than 300 cases

“…For instance, pure alexia is a selective disorder of reading and occurs as a consequence of damage to the left occipitotemporal cortex-the so-called visual word form area (VWFA; Dehaene & Cohen, 2011 disputed the selectivity of this disorder by demonstrating that individuals with pure alexia are also impaired in recognizing other visual stimuli (Behrmann, Nelson, & Sekuler, 1998;Roberts et al, 2013;Roberts et al, 2015), which also elicit activation in the VWFA in neurologically intact participants (for review and a computational implementation, see , 2014Price & Devlin, 2011). Interestingly, individuals with DD have also been reported to show a hypo-activation of the VWFA and an impairment in processing non-verbal visual stimuli (e.g., Sigurdardottir et al, 2017) as, for instance, faces (e.g., Gabay et al, 2017). The measure of processing speed in WISC-IV uses non-verbal visual stimuli and the difficulties shown by children with DD on this task confirm a domain general impairment, supporting the predications of the triangle model (Woollams, 2014).…”

Visual Statistical Learning With Stimuli Presented Sequentially Across Space and Time in Deaf and Hearing Adults

“…Frost et al (2013) found that, in English L1 speakers, SL positively correlated with the ability to learn the structural properties of Hebrew (L2), a Semitic language that follows different statistical properties than those usually found in Indo-European languages. In addition to these studies, the link between SL and literacy is supported by the finding that individuals with dyslexia seem to show SL impairments (e.g., Gabay, Thiessen, & Holt, 2015;Sigurdardottir et al, 2017;but see R€ usseler, Gerth, & M€ unte, 2006).…”

Statistical learning abilities and their relation to language

“…Here also, the prediction is that a SL deficit may explain some of the difficulties these populations have with language processing and that they would therefore be characterized by impaired SL abilities. Special focus was directed to estimating SL abilities of individuals with dyslexia (Gabay, Thiessen, & Holt, ; Kahta & Schiff, ; Sigurdardottir et al, ), specific language impairment (Mainela‐Arnold & Evans, ), and agrammatism (Christiansen, Louise Kelly, Shillcock, & Greenfield, ), all reporting some degree of impaired SL performance among these clinical samples (see Saffran, for review). Together, then, all of these individual‐differences studies point to a clear pattern, supporting the involvement of SL in language…”