Neural correlates of phonological, orthographic and semantic reading processing in dyslexia

Available online 10 August 2018Developmental dyslexia is one of the most prevalent learning disabilities, thought to be associated with dysfunction in the neural systems underlying typical reading acquisition. Neuroimaging research has shown that readers with dyslexia exhibit regional hypoactivation in left hemisphere reading nodes, relative to control counterparts. This evidence, however, comes from studies that have focused only on isolated aspects of reading. The present study aims to characterize left hemisphere regional hypoactivation in readers with dyslexia for the main processes involved in successful reading: phonological, orthographic and semantic. Forty-one participants performed a demanding reading task during MRI scanning. Results showed that readers with dyslexia exhibited hypoactivation associated with phonological processing in parietal regions; with orthographic processing in parietal regions, Broca's area, ventral occipitotemporal cortex and thalamus; and with semantic processing in angular gyrus and hippocampus. Stronger functional connectivity was observed for readers with dyslexia than for control readers 1) between the thalamus and the inferior parietal cortex/ventral occipitotemporal cortex during pseudoword reading; and, 2) between the hippocampus and the pars opercularis during word reading. These findings constitute the strongest evidence to date for the interplay between regional hypoactivation and functional connectivity in the main processes supporting reading in dyslexia.Supported by grants (RYC-2014-15440, PSI2015-65696) from the Spanish Ministry of Economy and Competitiveness (MINECO), a grant (PI2016-12) from the Basque Government and a grant (Exp. 65/15) from the Programa Red guipuzcoana de Ciencia, Tecnología e Innovación from the Diputación Foral de Gipuzkoa (P.M.P-A.); a predoctoral grant from the Department of Education, Universities and Research from the Basque Government (M.O.); grant (PSI2015-64174P) from the MINECO (F.C.); grants (PSI2015-67353-R) from the MINECO and (ERC-2011-ADG-295362) from the European Research Council (M.C.). BCBL acknowledges funding from Ayuda Centro de Excelencia Severo OchoaSEV-2015-0490 from the MINECO

Efficacy of a visuomotor‐based intervention for children with reading and spelling disabilities: a pilot study

International audienceWe predicted that Arabic-speaking dyslexic children with spelling disorder benefit from a visual motor based remediation program for the development of letter knowledge and the improvement of spelling (dictation) as well as word and pseudo-word decoding. It was predicted that the mediation of visual motor training should be effective since the characteristics of Arabic script require such high-level functioning for the development of literacy skills. Twenty native Arabic children from grade 4 with specific learning disorders in reading (dyslexia) and spelling (dysorthographia) took part in this study. Participants were randomly divided in two equally sized groups, an experimental group (n=10; mean age=125.50 months ± 3.24) and a control group (n=10; mean age = 124.10 months ± 3.31). The intervention program focused on the development of visuo-motor representations of letters to strengthen letter-sound associations as a way to acquire the alphabetic principle needed for learning to read and write (sound to letter correspondence). Results revealed that the post intervention measures were better achieved in the experimental group than pre-intervention ones. Findings approve the efficiency of the visuomotor intervention program for the remediation of decoding and spelling disorders