We replicated and extended van Bergen et al.'s study in showing that the FR-children who develop dyslexia are likely to have a higher liability. Both the group comparisons and the parent-child relations highlight the importance of good RAN skills for reading acquisition.

Dyslexia is heritable and associated with phonological processing deficits that can be reflected in the event-related potentials (ERPs). Here, we recorded ERPs from 2-month-old infants at risk of dyslexia and from a control group to investigate whether their auditory system processes /bAk/ and /dAk/ changes differently. The speech sounds were presented in an oddball paradigm. The children were followed longitudinally and performed a word reading fluency test in second grade. The infant ERPs were subsequently analyzed according to high or low reading fluency in order to find a neurophysiological precursor of poor reading fluency. The results show that the fluent reading children (from both the at-risk and the control group) processed the speech sound changes differentially in infancy as indicated by a mismatch response (MMR). In the control group the MMR was frontally positive and in the fluent at-risk group the MMR was parietally positive. The non-fluent at-risk group did not show an MMR. We conclude that at-risk children who became fluent readers were better at speech processing in infancy than those who became non-fluent readers. This indicates a very early speech processing deficit in the group of later non-fluent readers.

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Do children who go on to develop dyslexia show normal verbal and nonverbal development before reading onset? According to the aptitude-achievement discrepancy model, dyslexia is defined as a discrepancy between intelligence and reading achievement. One of the underlying assumptions is that the general cognitive development of children who fail to learn to read has been normal. The current study tests this assumption. In addition, we investigated whether possible IQ deficits are uniquely related to later reading or are also related to arithmetic. Four-year-olds (N = 212) with and without familial risk for dyslexia were assessed on 10 IQ subtests. Reading and arithmetic skills were measured 4 years later, at the end of Grade 2. Relative to the controls, the at-risk group without dyslexia had subtle impairments only in the verbal domain, whereas the at-risk group with dyslexia lagged behind across IQ tasks. Nonverbal IQ was associated with both reading and arithmetic, whereas verbal IQ was uniquely related to later reading. The children who went on to develop dyslexia performed relatively poorly in both verbal and nonverbal abilities at age 4, which challenges the discrepancy model. Furthermore, we discuss possible causal and epiphenomenal models explaining the links between early IQ and later reading.