Atypical Callosal Morphology in Developmental Language Disorder

Introduction

Developmental language disorder (DLD) is common, yet the neurobiology of DLD is poorly understood. A key hypothesis suggests atypical functional lateralization of language, which might be accompanied structurally by a deficit in inter-hemispheric connectivity of language-related regions. Indeed, aberrations of the corpus callosum have been associated with language deficits in children with frank neurological lesions and/or born pre-term. In contrast, studies examining the corpus callosum in children with DLD remain elusive.

Objective

We aimed to expand this largely understudied field by comparing callosal morphology between 17 children with DLD and 17 typically developing children carefully matched for sex and age.

Methods

We analyzed high-resolution structural magnetic resonance imaging data applying a well-validated computational approach, which captures the thickness of the corpus callosum with a high regional specificity at 100 equidistant points.

Results

As shown in Fig. 1, we observed a significantly thinner corpus callosum, particularly in the splenium, in children with DLD compared to typically developing controls (DLD < CTL).

Conclusions

These findings indicating pronounced aberrations in the brain's largest whiter matter tract make an important contribution to an understudied field of research and support the theory that DLD is accompanied by atypical lateralization of language function.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Genome-wide association analyses of child genotype effects and parent-of-origin effects in specific language impairment

Specific language impairment (SLI) is a neurodevelopmental disorder that affects linguistic abilities when development is otherwise normal. We report the results of a genome-wide association study of SLI which included parent-of-origin effects and child genotype effects and used 278 families of language-impaired children. The child genotype effects analysis did not identify significant associations. We found genome-wide significant paternal parent-of-origin effects on chromosome 14q12 (P = 3.74 × 10⁻⁸) and suggestive maternal parent-of-origin effects on chromosome 5p13 (P = 1.16 × 10⁻⁷). A subsequent targeted association of six single-nucleotide-polymorphisms (SNPs) on chromosome 5 in 313 language-impaired individuals and their mothers from the ALSPAC cohort replicated the maternal effects, albeit in the opposite direction (P = 0.001); as fathers’ genotypes were not available in the ALSPAC study, the replication analysis did not include paternal parent-of-origin effects. The paternally-associated SNP on chromosome 14 yields a non-synonymous coding change within the NOP9 gene. This gene encodes an RNA-binding protein that has been reported to be significantly dysregulated in individuals with schizophrenia. The region of maternal association on chromosome 5 falls between the PTGER4 and DAB2 genes, in a region previously implicated in autism and ADHD. The top SNP in this association locus is a potential expression QTL of ARHGEF19 (also called WGEF) on chromosome 1. Members of this protein family have been implicated in intellectual disability. In summary, this study implicates parent-of-origin effects in language impairment, and adds an interesting new dimension to the emerging picture of shared genetic etiology across various neurodevelopmental disorders.

Changes in Mental Health in Adolescents with a History of Specific Language Impairment

Little is known about long-term mental health outcomes as individuals with specific language impairment (SLI) approach adulthood.

Aims:

This longitudinal study examined anxiety (Child Manifest Anxiety Scale; CMAS) and depression (Moods and Feelings Questionnaire; MFQ) during the critical period when adolescents finish compulsory education and then embark upon their chosen course of study or employment.

Method:

Eighty-nine adolescents with SLI and 90 typically developing (TD) peers were assessed during their final year of compulsory schooling (16 years) and one year later.

Results:

At 16 years, there is a greater risk of both anxiety and depression in adolescents with SLI compared to their peers. Group scores for adolescents with SLI were significantly higher on both the CMAS (p< .001) and the MFQ (p< .01). However, while this finding is replicated at 17 years for anxiety symptoms (p< .01), there is a significant decrease in depressive symptoms for adolescents with SLI across time such that risk of depression is comparable to TD peers at 17 years. Scores for TD adolescents remain remarkably stable across this period. Poor mental health symptoms were not related to measures of nonverbal IQ, language, literacy or sociability but were associated with higher levels of shyness.

Conclusion:

Notwithstanding a sustained, elevated risk of anxiety symptoms, there is an encouraging trend for a decrease in depressive symptoms as adolescents with SLI complete compulsory education. The findings are interpreted within a developmental psychopathology framework, focusing on the changing structure of intrapersonal and environmental processes that influence internalizing symptoms during mid-adolescence.

Genetic and phenotypic effects of phonological short-term memory and grammatical morphology in specific language impairment

Deficits in phonological short-term memory and aspects of verb grammar morphology have been proposed as phenotypic markers of specific language impairment (SLI) with the suggestion that these traits are likely to be under different genetic influences. This investigation in 300 first-degree relatives of 93 probands with SLI examined familial aggregation and genetic linkage of two measures thought to index these two traits, non-word repetition and tense marking. In particular, the involvement of chromosomes 16q and 19q was examined as previous studies found these two regions to be related to SLI. Results showed a strong association between relatives' and probands' scores on non-word repetition. In contrast, no association was found for tense marking when examined as a continuous measure. However, significant familial aggregation was found when tense marking was treated as a binary measure with a cut-off point of -1.5 SD, suggestive of the possibility that qualitative distinctions in the trait may be familial while quantitative variability may be more a consequence of non-familial factors. Linkage analyses supported previous findings of the SLI Consortium of linkage to chromosome 16q for phonological short-term memory and to chromosome 19q for expressive language. In addition, we report new findings that relate to the past tense phenotype. For the continuous measure, linkage was found on both chromosomes, but evidence was stronger on chromosome 19. For the binary measure, linkage was observed on chromosome 19 but not on chromosome 16.

Familial loading in specific language impairment: patterns of differences across proband characteristics, gender and relative type

There is now little doubt that both environmental factors and genes are likely to make important contributions to the aetiology of specific language impairment (SLI). The most commonly proposed model for understanding these influences is the multifactorial model. In the present study we examine two expectations based on this model: that there will be a systematic relationship between the severity of proband language scores and the rate and severity of SLI in relatives and that relatives will be more strongly affected if they are relatives of a proband of the more rarely affected gender (female) because the latter require a higher genetic liability to become equally impaired. Ninety-three probands and their 300 first-degree relatives participated in this study. Results showed a relationship between proband severity at age 14 and an increased rate of SLI in relatives. This relationship was strong for child siblings and was significant with respect to both rate of SLI and severity over a range of language and literacy measures. In contrast, higher levels of SLI among relatives of female rather than male probands was entirely disproved.

Verb schema use and input dependence in 5-year-old children with Specific Language Impairment (SLI)

BACKGROUND

It has been argued that children with Specific Language Impairment (SLI) use language in a conservative manner. For example, they are reluctant to produce word-plus-frame combinations that they have not heard in the input. In addition, there is evidence to suggest that their utterances replicate lexical and syntactic material from the immediate language environment.

AIMS

This study investigated further the linguistic conservatism of children with SLI. It addressed the hypothesis that these children have difficulties using syntactic schemas in a verb-general manner. It employed a technique pioneered by Childers and Tomasello in 2001 that aims to develop verb-general representations through the presentation of appropriate exemplars. In addition, it tested the hypothesis that children with SLI present with input-dependent language use.

METHODS & PROCEDURES

Twenty-four children with SLI (mean age 5;6 years) were matched to 23 typically developing children (mean age 3;5 years) on overall language abilities. The children experienced play sessions designed to simulate exemplar-based learning. Facilitative exemplars consisted of sentences that alternated between nouns and pronouns in the argument slots, e.g. 'Pooh's churning the plate. See, he's churning it'. The children were divided evenly into two groups. One group experienced facilitative exemplars, while the other group heard exemplars with no variation in the argument positions. The training effect was assessed with a procedure in which the children heard novel verbs in a non-transitive frame and were required to produce them in a transitive frame. In addition, the argument types of the children's responses (nouns versus pronouns) were analysed to investigate the issue of input dependence.

OUTCOMES & RESULTS

Few of the children produced novel verbs in the transitive. This result may indicate difficulties using the transitive, although a number of methodological difficulties may be responsible for this finding. As hypothesized, the children with SLI demonstrated greater input dependence in terms of the kind of arguments they used in responses during the training sessions.

CONCLUSIONS

Potential reasons for the low response rate of both groups during the testing stage are explored and a number of methodological adjustments proposed. It is argued that the greater input dependence of the children with SLI may reflect a tendency to reduce processing load within a limited capacity system. It is proposed that input dependence could be a fruitful new area for SLI research and an important issue in the design and delivery of therapy programmes.

Predicting pathways of specific language impairment: what differentiates good and poor outcome?

A group of 117 children who met criteria for Specific Language Impairment (SLI) at 7 years of age were reassessed at 11 years of age. The data gathered from both stages were used to identify predictors of good and poor outcome from earlier test assessments. Results of logistic regressions indicated that measures of narrative retelling skills and expressive syntax were the strongest predictors of overall prognosis. This finding persisted when a nonverbal measure was included as a predictor alongside language measures in the regression model. There was found to be a lack of independent predictive contribution of early measures of articulation to later overall prognosis. Demographic factors (maternal education and family income) were not differently distributed across outcome groups. The theoretical and practical implications of the findings are discussed.

Non-word repetition and language development in children with specific language impairment (SLI)

Non-word repetition has previously been found to correlate with language outcomes both in children who are language impaired and in those who are developing normally. This paper concerns a group of children identified as having specific language impairment (SLI) and follows the methods of Adams and Gathercole (2000) by taking children with the highest and the lowest non-word repetition scores at age 11. These children's language and literacy abilities were then compared. Despite the fact that high and low scorers were matched on Performance IQ tasks (Block Design and Picture Completion), all linguistic measures except for vocabulary assessments showed significant differences between the groups. The fact that these differences were present despite block design scores being identical for the two groups suggests that more than a general working memory deficit underlies the language difficulties. Furthermore, significant differences were noted on a digit-span task requiring processing and production of number words. A specific phonological memory difficulty may therefore be present over and above a subtle but more general processing limitation. The implications for SLI theory and practice are discussed.

Psycholinguistic markers for specific language impairment (SLI)

In this study 160 children, aged 11 years with a definite history of specific language impairment (SLI), completed four tasks that could be potential positive psycholinguistic markers for this impairment: a third person singular task, a past tense task, a nonword repetition task, and a sentence repetition task. This allowed examination of more than one type of marker simultaneously, facilitating both comparisons between markers and also evaluation of combinations of markers in relation to identifying SLI. The study also provided data regarding the markers in relation to nonverbal IQ, made use of new normative data on all tasks, and examined marker accuracy in relation to current language status. The results show that markers vary in accuracy, with sentence repetition (a previously unused marker) proving to be the most useful. This psycholinguistic marker shows high levels of sensitivity (90%), specificity (85%), and overall accuracy (88%), as well as being able to identify the majority of children whose current language status falls in the normal range despite a history of SLI.

Non-word repetition and grammatical morphology: normative data for children in their final year of primary school

It is likely that tests of phonological short-term memory (non-word repetition) and grammatical morphology (past tense, third-person singular) are clinical markers for specific language impairment (SLI). The study provides normative data on three specific tests covering the aforementioned areas for 100 children attending the final year of primary schooling (10-11 year olds). Data from typically developing age controls can be used to provide a benchmark against which to compare the ability of language-impaired children. This is particularly important given that the transition from primary to secondary schooling is a key stage in a child's education.

Follow-up of children attending infant language units: outcomes at 11 years of age

A large cohort of 242 children who had been attending infants language units at 7 years of age was followed up when the children were in their final year of primary school. Two hundred (83%) of the children were reassessed at 11 years of age on a wide battery of language and literacy measures, on a test of non-verbal ability, an autism checklist and a communication checklist. In total, 89% of children still scored < 1 SD from the mean on at least one test of language and the majority (63%) scored poorly on three or more assessments demonstrating widespread difficulties. Compared with non-verbal abilities at 7 years of age, a large proportion of the cohort also performed poorly on performance IQ subtests (28%). A further 10 children scored highly on a checklist for autistic spectrum disorder. Thus, only 115 (58%) children could be said to meet criteria for specific language impairment. A small group of 16 children appeared to have entirely resolved their difficulties. These outcomes and their implications for education and long-term impact of the disorder are discussed.

Classification of children with specific language impairment: longitudinal considerations

This paper reports on the longitudinal results of a large project involving 242 seven-year-old children attending language units in England. Following our work outlining 6 subgroups of children with language impairment (Conti-Ramsden, Crutchley, & Botting, 1997), we examine the stability of the 6 subgroups of children with specific language impairment already identified, using data collected from the same children at age 8 years. The findings suggest there is considerable stability in the patterns of difficulties delineated by the classification system involving 6 subgroups. Poorer stability was evident in the classification of the children across time with 45% of children moving across subgroups. The membership stability of the proposed classification system was very similar to that found when the children were classified into 3 subgroups following another well-known system (Rapin, 1996). The findings are discussed with particular reference to issues surrounding the classification of children with SLI.

Characteristics of children attending language units in England: a national study of 7-year-olds

The present investigation examined the characteristics of 7-year-old children attending language units in England. The study involved 242 participants who represented a randomized sample of all 7-year-old children spending 50% of more of the school week in a language unit. Results are discussed in terms of the following questions: what is the non-verbal ability of children attending language units?; do children attending language units fit the discrepancy criteria between verbal and non-verbal ability diagnostic of specific language impairment (SLI)?; and what types of language difficulties do children with SLI attending language units have?

Classification of children with specific language impairment: longitudinal considerations

This paper reports on the longitudinal results of a large project involving 242 seven-year-old children attending language units in England. Following our work outlining 6 subgroups of children with language impairment (Conti-Ramsden, Crutchley, & Botting, 1997), we examine the stability of the 6 subgroups of children with specific language impairment already identified, using data collected from the same children at age 8 years. The findings suggest there is considerable stability in the patterns of difficulties delineated by the classification system involving 6 subgroups. Poorer stability was evident in the classification of the children across time with 45% of children moving across subgroups. The membership stability of the proposed classification system was very similar to that found when the children were classified into 3 subgroups following another well-known system (Rapin, 1996). The findings are discussed with particular reference to issues surrounding the classification of children with SLI.

Verb use in specific language impairment

The aim of the present study was to use longitudinal data to provide a detailed profile of early word combinations by children with SLI. Three children with SLI were videotaped during mother-child interactions in the home over a 2-year period. The data obtained were compared to MLU-matched samples of normal language-learning children from Wells' (1981) longitudinal database, which provided a control for the linguistic measures used in this study. A range of analyses were carried out on controlled data samples in order to determine how the children with SLI's early utterances compared with those of MLU-matched normal language peers. The measures were specifically designed to assess the children's use of verbs and verb morphology because recent research has suggested that verbs may play a central role in the acquisition process, and children with SLI may have particular problems with verbs. We found that children with SLI used verbs less frequently, nouns more frequently, and were more input-dependent than their MLU-matched peers. The children with SLI used verb bare stems incorrectly more often than their MLU-matched counterparts. However, further analyses showed that this high frequency of incorrect bare stems may be at least partly due to the fact that children with SLI have particular difficulties using auxiliaries. Furthermore, the proportion of verb use that consisted of General All Purpose (GAP) verbs for children with SLI was similar to that of the MLU-matched children. The above findings were compared with those from other relevant studies of lexical diversity in children with SLI, and the potential implications of these data for theories of SLI language development were discussed, particularly with reference to Marchman and Bates' (1994) "critical mass" hypothesis.

The extent to which psychometric tests differentiate subgroups of children with SLI

This paper reports on the results of a large project involving 7-year-old children attending language units in England. A group of 242 children with specific language impairment (SLI) were assessed on a battery of psychometric tests. In addition, teacher interviews were carried out to ascertain teachers' opinions of the children's difficulties. Cluster analysis revealed six robust subgroups of children with language difficulties. The findings are discussed in the context of other approaches to the classification of language impairment in children with special reference to the work of Rapin and Allen (1987).

Bilingualism and specific language impairment in children attending language units

Bilingual children were found to form a distinct subgroup within a large cohort of children with specific language-impairment (SLI) attending language units across England. They differed from the cohort as a whole, and from a language-matched monolingual 'control' group, on measures including language profile on entry to the unit, performance on standardised tests, emotional-behavioural state and probable future educational placement. This paper sets out the nature of these differences in more detail, and suggests some possible explanations for them.

Concordance between teacher/therapist opinion and formal language assessment scores in children with language impairment

As part of a wider study, 242 children attending language units attached to mainstream schools were assessed on a number of formal language assessments. In addition, each child's teacher was asked to state whether, for each of four areas of language difficulty, the participant exhibited this impairment. The four areas were: articulation, phonology, syntax/morphology and semantic/pragmatic impairment. This report compares test results between children thought by their teacher or therapist to show each impairment and those not thought clinically to show the difficulty. Investigations into suitable cut-off scores for the tests used were also examined using level of agreement between the two modes of assessment as criteria. For articulation, phonology and syntax/morphology, teacher opinion was found to discriminate significantly on at least some formal tests. However, for children with semantic/pragmatic impairment, no tests used identified their problems. Furthermore, by use of 25th centile cut-off scores, 66% agreement levels between teacher and test groupings were found in all but the group with semantic/pragmatic impairments. The importance and limitations of analysis of teacher-test concordance is discussed as well as the current lack of suitable formal assessment material for semantic and pragmatic language impairment.

Contingency and breakdown: children with SLI and their conversations with mothers and fathers

The present study aimed to investigate the nature and frequency of parental recasts (both mothers and fathers) to children with SLI as compared to normal language learning children of the same language stage including their younger siblings. The comparisons were made within the framework of discourse function to include behaviors related to conversational contingency and conversational breakdown. Results showed that children with SLI at the early stages of development experience a simple recast gap in their linguistic input. Qualitative differences in the context in which recasts occurred were also noted. Furthermore, some differences between mothers and fathers were found. These findings are discussed in light of previous research with particular reference to the Rare Event Theory and the Bridge Hypothesis.

Communicative skills in children with specific language impairments: a comparison with their language-matched siblings

The purpose of this study was to compare the pragmatic skills of five children with Specific Language Impairments (SLI) and their Mean Length of Utterance-matched younger siblings, thus in part controlling for home language environment and expressive language level. Data were videotaped as mother-child free play in the home. Children's communicative acts were coded on three levels (social interchange, speech act, and conversational). Analysis of each level separately indicated generally comparable performance within sibling pairs. However, when the three levels were integrated into a measure of pragmatic flexibility, the children with SLI were found to demonstrate a more varied repertoire than their younger, normally developing siblings.

Conversational interaction and decision-making in children with specific language impairment

The present investigation examines decision-making in conversational contexts for children with specific language impairment (SLI) and two sets of control groups: same-age peers and children matched for mean length of utterance (MLU). In a dyadic situation, it was found that children with SLI made as many verbal winning moves as age-control peers and more than the MLU-control children. Non-verbally, the children with SLI had more winning moves than the age-control peers. These results are discussed theoretically, in light of previous research on peer interaction, and practically, in terms of implications for clinician-researchers working with children with SLI.

Maternal recasts and other contingent replies to language-impaired children

Mothers' recasts and other contingent replies to their children's utterances were examined in two groups of mother-child dyads. In one group there were 14 dyads that contained language-impaired children; in the other there were 14 dyads that contained non-language-impaired children. Results indicated that mothers' overall use of recasts, as well as other contingent replies, was highly similar for the two groups, except that complex recasts were used more often by the mothers of non-language-impaired children. Differences in discourse functions were also observed. Mothers of language-impaired children used recasts less often than mothers of non-language-impaired children to respond to, or request clarification of, their children's utterances. Further, they more often used such replies to serve the functions of information requests, assertion, or direction. Recasts were also found to vary in relation to observed differences in children's intelligibility and in contrasting patterns of dialogue initiation for the two kinds of dyads.

Mother-child dialogues: a comparison of normal and language impaired children

This study explored similarities and differences in the dialogue of mother-child dyads with normal and language impaired children. The dialogue code used in this study assessed the child's ability to participate and sustain dialogue, and the mothers' ability to adjust to their children's level of functioning in discourse. It was found that: Language impaired children are not as skilled as younger normal language learning children of the same language stage in their ability to participate and maintain conversation; and that mothers of both normal and language impaired children adjust their language to meet the needs of their conversational partners. Implications for the language impaired mother-child dyad are discussed.

Mothers' discourse adjustments to language-impaired and non-language-impaired children

Mother's discourse adjustments addressed to language-impaired children and non-language-impaired children were studied. Mother-child dyads with 14 language-impaired children and 14 MLU-matched non-language-impaired children served as subjects. The mothers' discourse was compared on the following measures: meaning illocutions, cohesion ilocutions, and dialogue participation. The children's participation in dialogue was also analyzed. Results indicated that the mothers' speech addressed to the two groups of children was highly similar, but the discourse performance of the language-impaired children was not like that of the non-language-impaired children. The clinical implications of these findings for the language-impaired population are discussed.