Common aetiology for diverse language skills in 41/2-year-old twins

Multivariate genetic analysis was used to examine the genetic and environmental aetiology of the interrelationships of diverse linguistic skills. This study used data from a large sample of 4 1/2 year-old twins who were tested on measures assessing articulation, phonology, grammar, vocabulary, and verbal memory. Phenotypic analysis suggested two latent factors: articulation (2 measures) and general language (the remaining 7), and a genetic model incorporating these factors provided a good fit to the data. Almost all genetic and shared environmental influences on the 9 measures acted through the two latent factors. There was also substantial aetiological overlap between the two latent factors, with a genetic correlation of 0·64 and shared environment correlation of 1·00. We conclude that to a large extent, the same genetic and environmental factors underlie the development of individual differences in a wide range of linguistic skills

Heritable risk factors associated with language impairments

There is a strong genetic contribution to children’s language and literacy impairments. The aim of this study was to determine which aspects of the phenotype are familial by comparing 34 parents of probands with language/literacy impairments and 33 parents of typically developing probands. The parents responded to questionnaires regarding previous history for language/reading impairment and participated in psychometric testing. The psychometric test battery consisted of tests assessing non-verbal IQ, short-term memory, articulation, receptive grammar, reading abilities and spelling. Self-report measures demonstrated a higher prevalence of language and literacy impairments in parents of affected probands (32%) compared with parents of unaffected probands (6%). The two groups of parents differed significantly in their performance on the non-word repetition, oromotor and digit span tasks. Non-word repetition gave the best discrimination between the parent groups even when the data from the parents who actually were impaired as ascertained by direct testing or self-report were removed from the analyses. This suggests that non-word repetition serves as a marker of a family risk for language impairment. The paper concludes with a discussion of issues associated with ascertainment of specific language impairment (SLI)

Atypical long-latency auditory event-related potentials in a subset of children with specific language impairment

It has been proposed that specific language impairment (SLI) is the consequence of low-level abnormalities in auditory perception. However, studies of long-latency auditory ERPs in children with SLI have generated inconsistent findings. A possible reason for this inconsistency is the heterogeneity of SLI. The intraclass correlation (ICC) has been proposed as a useful statistic for evaluating heterogeneity because it allows one to compare an individual's auditory ERP with the grand average waveform from a typically developing reference group. We used this method to reanalyse auditory ERPs from a sample previously described by Uwer, Albrecht and von Suchodoletz (2002). In a subset of children with receptive SLI, there was less correspondence (i.e. lower ICC) with the normative waveform (based on the control grand average) than for typically developing children. This poorer correspondence was seen in responses to both tone and speech stimuli for the period 100–228 ms post stimulus onset. The effect was lateralized and seen at right- but not left-sided electrodes

Heritability of specific language impairment depends on diagnostic criteria

Heritability estimates for specific language impairment (SLI) have been inconsistent. Four twin studies reported heritability of 0.5 or more, but a recent report from the Twins Early Development Study found negligible genetic influence in 4-year-olds. We considered whether the method of ascertainment influenced results and found substantially higher heritability if SLI was defined in terms of referral to speech and language pathology services than if defined by language test scores. Further analysis showed that presence of speech difficulties played a major role in determining whether a child had contact with services. Childhood language disorders that are identified by population screening are likely to have a different phenotype and different etiology from clinically referred cases. Genetic studies are more likely to find high heritability if they focus on cases who have speech difficulties and who have been referred for intervention

Early phonological and sociocognitive skills as predictors of later language and social communication outcomes

Background:  Previous studies of outcome for children with early language delay have focused on measures of early language as predictors of language outcome. This study investigates whether very early processing skills (VEPS) known to underpin language development will be better predictors of specific language and social communication outcomes than measures of language itself. Method:  Participants were 163 children referred to clinical services with concerns about language at 2;6–3;6 years and followed up at 4–5 years. Novel assessments of phonological and sociocognitive processing were administered at Time 1 (T1), together with a standardised test of receptive and expressive language, and parental report of expressive vocabulary. The language test was re-administered at Time 2 (T2), together with assessments of morphosyntax and parental reports of social communication. Results:  Intercorrelations at and between T1 and T2 were high, and dissociations were rare. Ordinal regressions were run, entering predictors singly and simultaneously. With the exception of the phonological task, every early measure on its own was significantly predictive of most outcomes, and receptive language was the strongest all-round predictor. Results of simultaneous entry, controlling for the effect of other predictors, showed that early language was the strongest predictor of general language outcome, but early phonology was the strongest predictor of a measure of morphosyntax, and early sociocognition the strongest predictor of social communication. Conclusions:  Language measures which draw on a wide range of skills were the strongest overall predictors of general language outcomes. However, our VEPS measures were stronger predictors of specific outcomes. The clinical and theoretical implications of these findings are discussed

Vulnerability to bullying in children with a history of specific speech and language difficulties

This is an electronic version of an article published in Lindsay, Geoff and Dockrell, Julie and Mackie, Clare (2008) Vulnerability to bullying in children with a history of specific speech and language difficulties. European Journal of Special Needs Education, 23 (1). pp. 1-16. European Journal of Special Needs Education is available online at: http://www.informaworld.com/10.1080/0885625070179120

Emotional health in adolescents with and without a history of specific language impairment (SLI)

Objective:  This study examined the emotional health of adolescents with and without specific language impairment (SLI). Method:  One hundred and thirty-nine adolescents with a history of SLI (15;10 years) and a peer group of 124 adolescents with normal language development (NLD) (15;11 years) participated, who were in their final year of compulsory schooling. The risk of emotional difficulties was assessed using the Moods and Feelings Questionnaire (MFQ) and the Child Manifest Anxiety Scale-R (CMAS-R). Comprehensive language and cognition data were available for all participants (NLD and SLI) concurrently and also longitudinally for those with SLI. Results:  A clear increased risk of emotional health symptoms was found for the SLI group on both self- and parental-report. Girls scored less favourably than boys when groups were combined, but these were due to the effect of the NLD group, with no gender differences found in the SLI group. Direct links with language and cognition were not obvious. Instead, more diffuse factors such as family history of emotional health difficulties may warrant further investigation. Conclusion:  There is a marked higher rate of anxiety and depression symptoms in adolescents with SLI. However, these do not appear to be a direct result of impoverished communicative experiences

Longitudinal relationships between speech perception, phonological skills and reading in children at high-risk of dyslexia

Speech perception deficits are commonly reported in dyslexia but longitudinal evidence that poor speech perception compromises learning to read is scant. We assessed the hypothesis that phonological skills, specifically phoneme awareness and RAN, mediate the relationship between speech perception and reading. We assessed longitudinal predictive relationships between categorical speech perception, phoneme awareness, RAN, language, attention and reading at ages 5½ and 6½ years in 237 children many of whom were at high risk of reading difficulties. Speech perception at 5½ years correlated with language, attention, phoneme awareness and RAN concurrently and was a predictor of reading at 6½ years. There was no significant indirect effect of speech perception on reading via phoneme awareness, suggesting that its effects are separable from those of phoneme awareness. Children classified with dyslexia at 8 years had poorer speech perception than age-controls at 5½ years and children with language disorders (with or without dyslexia) had more severe difficulties with both speech perception and attention control. Categorical speech perception tasks tap factors extraneous to perception, including decision-making skills. Further longitudinal studies are needed to unravel the complex relationships between categorical speech perception tasks and measures of reading and language and attention

Dyslexia and Developmental Language Disorder : comorbid disorders with distinct effects on reading comprehension

BACKGROUND: Reading comprehension draws on both decoding and linguistic comprehension, and poor reading comprehension can be the consequence of a deficit in either of these skills. METHODS: Using outcome data from the longitudinal Wellcome Language and Reading Project, we identified three groups of children at age 8 years: children with dyslexia (N = 21) who had deficits in decoding but not oral language, children with Developmental Language Disorder (DLD; N = 38) whose decoding skills were in the normal range, and children who met criteria for both dyslexia and DLD (N = 29). RESULTS: All three groups had reading comprehension difficulties at the ages of 8 and 9 years relative to TD controls though those of the children with dyslexia were mild (relative to TD controls, d = 0.51 at age 8, d = 0.60 at age 8); while the most severe problems were found in the comorbid dyslexia + DLD group (d = 1.79 at age 8, d = 2.06 at age 9) those with DLD also had significant difficulties (d = 1.56 at age 8, d = 1.56 at age 9). CONCLUSIONS: These findings confirm that children with dyslexia or DLD are at-risk for reading comprehension difficulties but for different reasons, because of weak decoding in the case of dyslexia or weak oral language skills in the case of DLD. Different forms of intervention are required for these groups of children, targeted to their particular area(s) of weakness