Reis, A. 1 , Araújo, S. 2 , Salomé, I. 1 & Faísca, L. 1
1 Department of Psychology and Educational Sciences and Center for Biomedical Research - CBMR, University of Algarve, Faro, Portugal
2 Faculdade de Psicologia, Universidade de Lisboa, Lisboa, Portugal
An individual diagnosed with dyslexia in childhood typically remains dyslexic throughout life. However, compared with children, the cognitive profile of adults with dyslexia is less explored. This meta-analytic study intended to clarify to what extent and how do adults with dyslexia differ from skilled adult readers on measures related to overall reading competence and reading predictors and to what extent their reading profile is modulated by orthography. 180 studies comparing adults with dyslexia and matched controls were reviewed. Adults with dyslexia still exhibit poor performance on almost all reading and writing tasks expressed by large effect sizes (d > 1.50), except for Reading Comprehension (d = 0.77). Orthographic opacity is a significant moderator of the size of the deficit in word reading accuracy, being this weaker on Transparent (d =1.08), than on Intermediate (d =1.42) and Opaque (d =1.60) orthographies. Our meta-analysis shows that reading and writing difficulties are a hallmark of dyslexia that persist into adulthood, mainly reflected in speed measures. Moreover, symptoms are more severe for reading and spelling than for measures tapping into the cognitive processes underlying reading skills. Dyslexia has less marked symptoms on transparent orthographies, and accuracy can better discriminate among readers across orthographic systems.