Cognitive and familial risk evidence converged: A data-driven identification of distinct and homogeneous subtypes within the heterogeneous sample of reading disabled children.

The evident degree of heterogeneity observed in reading disabled children has puzzled reading researchers for decades. Recent advances in the genetic underpinnings of reading disability have indicated that the heritable, familial risk for dyslexia is a major risk factor. The present data-driven, classification attempt aims to revisit the possibility of identifying distinct cognitive deficit profiles in a large sample of second to fourth grade reading disabled children.

Evidence for a specific cross-modal association deficit in dyslexia: an electrophysiological study of letter-speech sound processing.

The phonological deficit theory of dyslexia assumes that degraded speech sound representations might hamper the acquisition of stable letter-speech sound associations necessary for learning to read. However, there is only scarce and mainly indirect evidence for this assumed letter-speech sound association problem. The present study aimed at clarifying the nature and the role of letter-speech sound association problems in dyslexia by analysing event-related potentials (ERP) of 11-year-old dyslexic children to speech sounds in isolation or combined with letters, which were presented either simultaneously with or 200 ms before the speech sounds.

Is there a causal link from a phonological awareness deficit to reading failure in children at familial risk for dyslexia?

The knowledge that reading and phonological awareness are mainly reciprocally related has hardly influenced the status of a phonological awareness deficit as the main cause of a reading deficit in dyslexia. Because direct proofs for this theory are still lacking we investigated children at familial risk for dyslexia in kindergarten and first grade. The familial risk was genuine; 40% developed reading deficits in first grade.