Author Description

Understanding the mechanisms responsible for developmental dyslexia (DD) is a key challenge for researchers. A large literature, mostly concerned with learning to read in opaque orthographies, emphasizes phono-logical interpretations of the disturbance. Other approaches focused on the visual-per-ceptual aspects of orthographic coding. Recently, this perspective was supported by imaging data showing that individuals with DD have hypo-activation in occipito-temporal areas (a finding common to both transpar-ent and opaque orthographies). Nevertheless, it is difficult to infer causal relationships from activation data. Accommodating these findings within the cognitive architecture of reading processes is still an open issue. This is a general problem, which is present in much of the literature. For example, several studies investigating the perceptual and cognitive abilities that distinguish groups of children with and without DD failed to provide explicit links with the reading process. Thus, several areas of investigation (e.g., acoustic deficits or magnocellular deficiencies) have been plagued by replication failures. Furthermore, much research has neglected the possible contribution of comorbid symptoms. By contrast, it is now well established that developmental disorders present a large spectrum of homotopic and heterotopic co-morbidities that make causal interpretations problematic. This has led to the idea that the etiology of learning difficulties is multifactorial, thus challenging the traditional models of DD. Recent genetic studies provide information on the multiple risk factors that contribute to the genesis of the disturbance. Another critical issue in DD is that much of the research has been conducted in English-speaking individuals. However, English is a highly irregular orthography and doubts have been raised on the appropriateness of automatically extending interpretations based on English to other more regular orthographies. By cont