Precursors of Literacy Delay among Children at Genetic Risk of Dyslexia

Abstract

This paper reports the literacy skills of 63 children selected as being at genetic risk of dyslexia compared with 34 children from families reporting no history of reading impairment. Fifty-seven per cent of the at-risk group were delayed in literacy development at 6 years compared with only 12% of controls. The "unimpaired" at-risk group were not statistically different from controls on most cognitive and language measures at 45 months, whereas the literacy-delayed group showed significantly slower speech and language development, although they did not differ from controls in nonverbal ability. Letter knowledge at 45 months was the strongest predictor of literacy level at 6 years. In addition, early speech and language skills predicted individual differences in literacy outcome and genetic risk accounted for unique variance over and above these other factors. The results are discussed in terms of an interactive developmental model in which semantic and phonological skills support early reading acquisition.

Cognitive profiles of poor readers of Kannada

“…Not surprisingly, the difficulty with symbol knowledge cooccurred with delays in all components of reading: poor accuracy, slow rate of reading, and more errors in reading comprehension. In alphabetic languages, letter knowledge is a predictor of individual differences (see Adams, 1990;Seymour, 2005 for reviews) and poor readers of alphabetic languages take longer to master the letter set (Gallagher, Frith, & Snowling 2000;Scarborough, 1990). Letter knowledge in alphabetic languages (i.e.…”

Why is letter-name knowledge such a good predictor of learning to read?

“…The predictive relationship between preschool letter naming skills and school reading skills has been substantiated in studies combining LNK and letter-sound knowledge into a single measure of letter knowledge (Duncan & Seymour, 2000;Gallagher, Frith & Snowling, 2000;Riley, 1996;Tunmer, Herriman, & Nesdale, 1988). Pooling letter naming and sounding scores has the great interest to provide more complete information about what children know about letters.…”

Age-of-Acquisition, Word Frequency, and Neighborhood Density Effects on Spoken Word Recognition by Children and Adults☆

“…Several researchers have proposed that spoken word representations become more completely specified and/or segmentally structured with vocabulary growth-i.e., as a result 1 The emergent position is closely allied with the "phonological representations" hypothesis of dyslexia (see Goswami, 1999;Snowling & Hulme, 1994), according to which dyslexic children or those at risk for dyslexia have "fuzzy" (i.e., degraded, distorted, or incomplete) speech representations that limit phoneme awareness and ultimately early reading achievement. Those for less frequent, later-acquired word forms may be especially impaired (Gallagher, Frith, & Snowling, 1999;Snowling, Goulandris, Bowlby, & Howell, 1986), suggesting that lexical restructuring in terms of greater segmental specificity and distinctness is delayed, rather than qualitatively different from that in children without reading difficulties (see also Metsala, 1997b). The emergent position is, however, broader inasmuch as it is intended to characterize normal development and individual variation in reading success, as well as the difficulties experienced by children with extreme reading problems.…”

“…of pressures to distinguish between an increasing number of items in the mental lexicon (e.g., Charles-Luce & Luce, 1995;Fowler, 1991;Jusczyk, 1993;Metsala, 1997a;Nittrouer, 1996;Walley, 1993). Indeed, differences in vocabulary knowledge have been observed for children varying in phoneme awareness and/or reading proficiency (Chaney, 1994;Gallagher et al, 1999;McBride-Chang et al, 1997;Metsala, 1999;Scarborough, 1990). However, such differences have not been related to variations in speech processing itself, and there is little information about what other factors promote advances in speech perception and spoken word recognition ability.…”

“…For example, 5-and 8-year-olds were as sensitive as adults to errors in early-acquired words; 8-year-olds were as sensitive as adults for words of intermediate AOA status, whereas 5-year-olds were less able to discriminate mispronounced and intact versions; each of the age comparisons was significant for later-acquired words. (Dyslexic children also have particular difficulty recognizing and repeating low-frequency words and nonwords; Gallagher et al, 1999;Snowling et al, 1986). Metsala (1997a) studied the recognition of high-and low-frequency words by 7-, 9-, and 11-year-olds and adults in the gating task, where increasing amounts of acoustic-phonetic input are presented from word-onset over a series of trials.…”