Early language development in children with a genetic risk of dyslexia

Abstract

We report on a prospective longitudinal research programme exploring the connection between language acquisition deficits and dyslexia. The language development profile of children at-risk for dyslexia is compared to that of age-matched controls as well as of children who have been diagnosed with specific language impairment (SLI). The experiments described concern the perception and production of grammatical morphology, categorical perception of speech sounds, phonological processing (non-word repetition), mispronunciation detection, and rhyme detection. The results of each of these indicate that the at-risk children as a group underperform in comparison to the controls, and that, in most cases, they approach the SLI group. It can be concluded that dyslexia most likely has precursors in language development, also in domains other than those traditionally considered conditional for the acquisition of literacy skills. The dyslexia-SLI connection awaits further, particularly qualitative, analyses.

Profiles of strengths and weaknesses in dyslexia and other learning difficulties

“…Weaknesses compared to control levels in literacy and phonological measures were as large, if not larger, amongst the other SEN groups, particularly the SLD and MLD groups (see Figure 1). These data were consistent with findings for deficits in literacy (reading and spelling) and phonological processing (awareness, memory and rapid access) amongst children with generally low scores on IQ-based tests (Ellis et al, 1996;Share, 1996;Siegel, 1988;Stanovich & Siegel, 1994;Stanovich & Stanovich, 1997) and amongst children with a history of language impairments (Bishop et al, 1999;Briscoe, Bishop, & Norbury, 2001;Catts et al, 2002;Goulandris, Snowling, & Walker, 2000;Van Alphen et al, 2004;Wiig, Zureich, & Chan, 2000). The findings of such studies, and the data reported in the present paper, suggest that either the majority of children with dyslexia, MLD and SLD should be treated identically in educational programmes designed to remediate literacy-related weaknesses or that further measures need to be considered to specifically differentiate each of these SEN groups from normal development.…”

A Nonword Repetition Task for Speakers With Misarticulations: The Syllable Repetition Task (SRT)

“…Findings from a series of well-controlled word learning studies assessing auditory-perceptual processes by Edwards and Munson and colleagues (e.g., Edwards, Fox, & Rogers, 2002; Munson, 2006; Munson, Edwards, & Beckman, 2005; Munson, Kurtz, & Windsor, 2005) have led these investigators to conclude that children with speech sound disorder have “poorly specified primary representations” due to “difficulties forming robust representations of the acoustic-auditory and articulatory characteristics of speech” (Munson, Baylis, Krause, & Kim, in press). Munson and colleagues (in press) further posit that auditory-perceptual encoding deficits may be the source of speech production errors in speech sound disorders, noting that many speech production models emphasize that “…acoustic/perceptual representations for words serve as targets during speech production (e.g., Guenther, 1995; Pierrehumbert, 2002).” Relevant findings and discussions on the contribution of auditory-perceptual encoding processes to word learning and to the accuracy of nonword repetition include Alphen et al, 2004; Bishop et al, 1999; Coady, Evans, Mainela-Arnold, and Kluender, 2006; Coady, Kluender, and Evans, 2005; Evans, Viele, Kass, and Tang, 2002; Reuterskiöld-Wagner, Sahlén, and Nyman, 2005; Rvachew, Ohberg, Grawburg, and Heyding, 2003; and Storkel, 2004.…”

Decreased Sensitivity to Phonemic Mismatch in Spoken Word Processing in Adult Developmental Dyslexia

“…Results were not provided for the different word and syllable positions. Van Alphen et al (2004) also investigated children at-risk of dyslexia on a mispronunciation detection task in which the word-initial mismatches were either minimal (only wrong place of articulation of the consonant; e.g., vebra for zebra 'zebra') or maximal (place of articulation, manner and voicing were wrong, e.g., pebra for zebra). All participants made more correct detections in the maximal than in the minimal condition, but the at-risk children showed more difficulty in detecting small/minimal phonological mispronunciations than controls.…”