Developmental dyslexia in a transparent orthography: A study of Spanish dyslexic children

Abstract

Spanish-speaking children learn to read words written in a relatively transparent orthography. Variations in orthographic transparency may shape the manifestation of reading difficulties. This study was intended to help clarify the nature of developmental dyslexia in Spanish. Developmental dyslexic group (DD) were compared to two control groups, a chronological age-matched control group (CA) and a reading level-matched control group (RL). Measures included naming speed, verbal working memory (WM), phonological short-term memory (STM), phonemic awareness, and different reading subtests (letter, word and pseudoword reading, punctuation mark, reading skills). On the reading subtests, accuracy and reading speed were measured. Results demonstrated that developmental dyslexics show a severe deficit in lexical access on accuracy and speed measures, in addition to reading-related cognitive deficits in areas such as naming speed, verbal WM, phonological STM, and phonemic awareness. Hierarchical cluster analysis demonstrated that a subgroup of children with DD showed lower IQs and more severe reading-related cognitive deficits in naming speed, verbal WM, and phonological STM. Our results are consistent with studies conducted in the Spanish language and in other transparent orthographies.