Misunderstandings about developmental dyslexia: a historical overview.

Developmental dyslexia is a reading disorder unrelated to intellectual disability, inadequate teaching systems or poor motivation for schooling. The first attempts to understand such difficulty of learning to read, connected the problem to a primary 'visual defect'. Since then, several models have been developed. In the last decades, autopsy and histopathological studies on the brain of developmental dyslexics provided neuroanatomical evidence of structural and morphological differences between the normal and dyslexic brains. Furthermore, neuroimaging studies allowed to understand the neural systems of reading and dyslexia. According to more recent studies, developmental dyslexia appears as a language-related neurodevelopmental disorder with a deficit in phonological decoding and visuospatial organization of the language code. Therefore, dyslexia is viewed as a multicomponential and complex disorder. Consequently, rehabilitation should be aimed at both the recovery of linguistic decoding processes and the improvement of visuo-spatial and attentional processes. This brief overview should be a valuable tool for a deeper understanding of dyslexic disorder. Literature searches in Medline, PsycINFO, EMBASE, Scopus, PubMed, Web of Science identified one hundred articles focusing attention on how this disorder has been considered over the years.