Background: Analyses from the Jyväskylä Longitudinal Study of Dyslexia project show that the key childhood predictors (phonological awareness, short-term memory, rapid naming, expressive vocabulary, pseudoword repetition, and letter naming) of dyslexia differentiate the group with reading disability (n ¼ 46) and the group without reading problems (n ¼ 152) at the end of the 2nd grade. These measures were employed at the ages of 3.5, 4.5 and 5.5 years and information regarding the familial risk of dyslexia was used to find the most sensitive indices of an individual child's risk for reading disability. Methods: Age-specific and across-age logistic regression models were constructed to produce the risk indices. The predictive ability of the risk indices was explored using the ROC (receiver operating curve) plot. Information from the logistic models was further utilised in illustrating the risk with probability curve presentations. Results: The logistic regression models with familial risk, letter knowledge, phonological awareness and RAN provided a prediction probability above .80 (area under ROC). Conclusions: The models including familial risk status and the three above-mentioned measures offer a rough screening procedure for estimating an individual child's risk for reading disability at the age of 3.5 years. Probability curves are presented as a method of illustrating the risk.

Lyytinen, H. (2010). Language development, literacy skills and predictive connections to reading in Finnish children with and without familial risk for dyslexia. Journal of Learning Disabilities, 43 (4), 308-321. http://dx

The authors examined the developmental trajectories of children's early letter knowledge in relation to measures spanning and encompassing their prior language-related and cognitive measures and environmental factors and their subsequent Grade 1 reading achievement. Letter knowledge was assessed longitudinally at ages 4.5, 5.0, 5.5, and 6.5 years; earlier language skills and environmental factors were assessed at ages 3.5 and 4.5 years; and reading achievement was assessed at the beginning and end of Grade 1. The analyses were conducted on a longitudinal data set involving children with and without familial risk for dyslexia. Emerging from the trajectory analysis of letter knowledge were 3 separate clusters: delayed (n = 63), linearly growing (n = 73), and precocious (n = 51). The members of the delayed cluster were predominantly children with familial risk for dyslexia, and the members of the precocious cluster were predominantly control group children. Phonological sensitivity, phonological memory, and rapid naming skills predicted delayed letter knowledge. Environmental predictors included level of maternal education and the amount of letter name teaching. Familial risk for dyslexia made a significant contribution to the predictive relations. Membership in the delayed cluster predicted poor reading performance at Grade 1.

Children at risk for familial dyslexia (n = 107) and their controls (n = 93) have been followed from birth to school entry in the Jyvaskyla Longitudinal study of Dyslexia (JLD) on developmental factors linked to reading and dyslexia. At the point of school entry, the majority of the at-risk children displayed decoding ability that fell at least 1 SD below the mean of the control group. Measures of speech processing were the earliest indices to show both group differences in infancy and also significant predictive associations with reading acquisition. A number of measures of language, including phonological and morphological skill collected repeatedly from age three, revealed group differences and predictive correlations. Both the group differences and the predictive associations to later language and reading ability strengthened as a function of increasing age. The predictions, however, tend to be stronger and the spectrum of significant correlations wider in the at-risk group. These results are crucial to early identification and intervention of dyslexia in at-risk children.

We examined the longitudinal predictors of nonword decoding, reading fluency, and spelling in three languages that vary in orthographic depth: Finnish, Greek, and English. Eighty-two English-speaking, 70 Greek, and 88 Finnish children were followed from the age of 5.5 years old until Grade 2. Prior to any reading instruction, they were administered measures of phonological awareness, letter knowledge, and rapid naming speed. In Grade 2, they were administered measures of nonword decoding, text-reading fluency, and spelling. The results showed that the model for nonword decoding in Greek was similar to that of Finnish (both have consistent grapheme-to-phoneme mappings) while the model for spelling in Greek was similar to that of English (both have some inconsistent phoneme-to-grapheme mappings). In addition, the models for nonword decoding and spelling in Finnish were similar, because Finnish is consistent in both directions. Letter knowledge dominated the prediction in each language. The predictable role of orthographic consistency on literacy acquisition is discussed.

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Present findings are drawn from the Jyväskylä Longitudinal Study of Dyslexia (JLD) in which about 100 children with familial risk of dyslexia and 100 control children have been followed from birth. In this paper we report data on reading development of the JLD children and their classmates, a total of 1750 children from four measurement points during the first two school years. In the total sample we examined whether heterogeneous developmental paths can be identified based on profiles of 1st through 2nd grade word recognition and reading comprehension skills after controlling for the classroom membership effect. Secondly we studied what kind of early language and literacy skill profiles and reading experiences characterize the children in the follow-up with differing reading development. Our analyses included comparisons of the reading development of the JLD children with and without familial risk for dyslexia. The mixture modelling procedure resulted in five reading subtypes: (1) 'Poor readers' with poor skills in both word recognition and reading comprehension, (2) 'Slow readers' with somewhat below average word recognition combined with faster than average growth in reading comprehension, (3) 'Poor comprehenders' with average word recognition combined with slower than average reading comprehension development, (4) 'Average readers' with average skills in both word recognition and reading comprehension, and (5) 'Good readers' with high level of performance in both reading skills. The children with familial risk for dyslexia performed on average at a lower level in all reading tasks than both their classmates and controls and they were over-represented in the reading subtypes with deficient fluent word recognition. Differences were found in the early language and literacy skill development of the reading subtypes.Reading Development Subtypes