Oral language deficits in familial dyslexia: A meta-analysis and review.

Abstract

This article reviews 95 publications (based on 21 independent samples) that have examined children at family risk of reading disorders. We report that children at family risk of dyslexia experience delayed language development as infants and toddlers. In the preschool period, they have significant difficulties in phonological processes as well as with broader language skills and in acquiring the foundations of decoding skill (letter knowledge, phonological awareness and rapid automatized naming [RAN]). Findings are mixed with regard to auditory and visual perception: they do not appear subject to slow motor development, but lack of control for comorbidities confounds interpretation. Longitudinal studies of outcomes show that children at family risk who go on to fulfil criteria for dyslexia have more severe impairments in preschool language than those who are defined as normal readers, but the latter group do less well than controls. Similarly at school age, family risk of dyslexia is associated with significantly poor phonological awareness and literacy skills. Although there is no strong evidence that children at family risk are brought up in an environment that differs significantly from that of controls, their parents tend to have lower educational levels and read less frequently to themselves. Together, the findings suggest that a phonological processing deficit can be conceptualized as an endophenotype of dyslexia that increases the continuous risk of reading difficulties; in turn its impact may be moderated by protective factors.

Predicting Developmental Dyslexia: A Brief Review of Genetics, Language and the Brain

“…Preschoolers with a familial risk of DD who ultimately are diagnosed with DD display poorer auditory processing skills, letter knowledge, and reduced sensitivity to rapid auditory processing compared to at-risk peers who do not receive a diagnosis of DD [1]. Furthermore, at-risk preschoolers demonstrate poorer articulatory skills, vocabulary knowledge, and phonological processing skills than control children [1]. At-risk school-age children display reduced nonverbal vocabulary than control children [1].…”

“…Infants and toddlers with a familial risk of DD who are ultimately diagnosed with DD display poorer articulatory skills, vocabulary knowledge, and grammar than peers with a familial risk of DD who do not develop DD [1]. Preschoolers with a familial risk of DD who ultimately are diagnosed with DD display poorer auditory processing skills, letter knowledge, and reduced sensitivity to rapid auditory processing compared to at-risk peers who do not receive a diagnosis of DD [1]. Furthermore, at-risk preschoolers demonstrate poorer articulatory skills, vocabulary knowledge, and phonological processing skills than control children [1].…”

“…A recent meta-analysis reviews oral language deficits in children with a familial risk of DD [1]. Infants and toddlers with a familial risk of DD who are ultimately diagnosed with DD display poorer articulatory skills, vocabulary knowledge, and grammar than peers with a familial risk of DD who do not develop DD [1].…”

“…A recent meta-analysis consisting of 420 children with DD reports that children with a first degree relative with DD have a 45% chance of also being diagnosed with DD [1]. A number of DD susceptibility genes have been identified, including DCDC2, DYX1CI, ROBO1, KIAA0319, and the majority of these genes play a role in neuronal migration and axonal development [14][15][16][17].…”

“…Nonetheless, many children struggle while learning to read, and as many as 11.6% percent of children are diagnosed with developmental dyslexia (DD) [1]. DD is a brainbased specific learning disability characterized by deficits in reading and reading-related skills, such as phonological awareness (the ability to manipulate phonemes, the smallest units of speech), spelling, and/or rapid visual/verbal manipulation of letters and/or words despite adequate intelligence [2].…”