Developmental cognitive genetics: how psychology can inform genetics and vice versa

Delayed auditory experience results in past tense production difficulties and working memory deficits in children with cochlear implants: A comparison with children with developmental language disorder

Extent evidence has shown that morphosyntax is one of the most challenging linguistic areas for children with atypical early language experiences. Over the last couple of years, comparisons between deaf children with CIs and children with DLD have gained interest - as cases of atypical early language experiences, including, but not restricted to, delayed onset of exposure to language input and language-processing difficulties. Evidence suggests that the morphosyntactic difficulties experienced by deaf children with CIs and children with DLD are very similar in nature. However, the few studies that have directly compared both groups are inconclusive, with deaf children with CIs either performing significantly better or on par with children with DLD. These differences in findings can be attributed, in part at least, to a failure to implement essential methodological controls - even more so given that deaf children with CIs comprise a very diverse population. The goal of the present study was to directly compare the performance of deaf children with CIs to that of children with DLD on a morphosyntactic ability known to be particularly difficult for both groups. Specifically, the present study conducted a detailed examination of the past tense marking abilities of deaf children with CIs and children with DLD while controlling for factors specific to deaf children with CIs, for children's basic cognitive abilities as well as for children's age, sex assigned at birth, and SES. Past tense verbs are particularly relevant as they are used as a marker of developmental language disorder (DLD) in children learning French. Moreover, extent evidence shows that deaf children with CIs and children with DLD have important WM difficulties, but also that there is an association between auditory perception, processing abilities, and working memory (WM) abilities as well as with the acquisition of morphological features, including tense marking. Unfortunately, no study has examined the relation between the accurate production of past tense verbs and WM abilities in children with CIs and children with DLD learning French. Fifteen deaf children with CIs between 5 and 7 years of age were compared to 15 children with DLD and to 15 typically-developing monolingual controls (MON), matched on important variables, using a past tense elicitation task as well as measures of phonological and nonverbal WM abilities. The results confirm that the deaf children with CIs and the children with DLD both performed significantly lower than the MON controls on the past tense elicitation task - suggesting that difficulties with past tense verbs in French might not only be a marker of DLD but, instead, a correlate of atypical language acquisition. Of importance, the present study is the first to show that deaf children with CIs perform significantly lower than children with DLD on a past tense elicitation task - highlighting the importance of using methodological controls. As well, significant correlations were found between the performance of the deaf children with CIs and of the children with DLD on the past tense elicitation task and their phonological and nonverbal WM abilities. Taken together with previous studies conducted in the same populations, this represents another evidence suggesting that early atypical language experiences result in language and WM deficits, including morphosyntactic difficulties.

Rhythmic Music Training's Effect on Syntactic Structure Processing among Malay Adolescents with Syntactic Specific Language Impairment

Background

Adolescents with syntactic specific language impairment (S-SLI) fail to comprehend which object questions. We hypothesised that rhythmic music training is more effective in treating this condition than conventional methods because music is often perceived as having a clear, isochronous beat or pulse. Thus, this study aims to investigate the effects of rhythmic music training on the syntactic structure processing of Malay which questions among native adolescents.

Methods

In this research study, the participants were three groups of Malay adolescents aged 13 years old-15 years old: i) adolescents with S-SLI with music training, ii) adolescents with S-SLI without music training and iii) typically developing adolescents. Before and after music training, the participants were given a sentence-picture matching task. Accuracy measures and reaction times were captured using E-Prime 2.0.

Results

The results indicated that with music training, the accuracy and reaction time associated with which object questions among the two SLI groups were significantly higher and lower, respectively.

Conclusion

The implications of using rhythmic music training in enhancing syntactic structure processing are also discussed.

The association of cognitive abilities with language disorder in 8-year-old children: A population-based clinical sample

BACKGROUND

Despite accumulated evidence that language development depends on basic cognitive processes, the balance in contributions of verbal and non-verbal cognitive skills to language abilities is still underexplored. Little is known about which cognitive measures best predict the degree of severity in children with language disorder (LD).

AIMS

To examine the association between verbal and non-verbal cognitive abilities with language abilities in typically developing and language impaired 8-year-old children, as well as which cognitive abilities are most effective in distinguishing LD severity levels.

METHODS & PROCEDURES

Children (N = 509) from the Language-8 Study, which oversampled probable cases of children with LD from a population-based cohort in Norway, were assessed at 8 years. Language skills were assessed using the Norwegian Clinical Evaluation of Language Fundamentals-4 (CELF-4). Children's verbal and non-verbal cognitive abilities were assessed via standardized cognitive measures. An exploratory factor analysis (EFA) was first conducted to uncover the underlying factor structure of the cognitive variables. Using a hierarchical multiple regression analysis, we then examined to what extent the non-verbal cognition factor explained language abilities above and beyond verbal cognition factors. Lastly, multinomial logistic regression was used to examine which cognitive measures best predicted the degree of severity in the children with LD.

OUTCOMES & RESULTS

The EFA resulted in three factors (Verbal Cognition, Processing Speed and Memory, and Non-Verbal Cognition). The hierarchical multiple regression analysis revealed that all three cognitive factors contributed significantly to individual variation in language abilities. Non-Verbal Cognition explained 5.4% variance in language abilities above and beyond that accounted for by Verbal Cognition and Processing Speed and Memory. Results from the multinomial logistic regression analysis indicated that cognitive subtests, including Familiar Sequences, WASI Vocabulary and WASI Similarities, not only distinguished LD from typically developing children, but were also efficient in distinguishing severity of LD symptoms.

CONCLUSIONS & IMPLICATIONS

This study confirms concurrent links between language and non-verbal cognitive skills above and beyond the contribution of verbal cognitive skills. The results provide further evidence that children with LD experience both language and cognitive problems in mid-childhood. Our findings suggest implications for LD intervention and diagnosis. The findings support the importance of measuring both verbal and non-verbal cognitive skills when making an LD diagnosis, and point to the potential of targeting underlying cognitive skills as one strategy to support language abilities.

WHAT THIS PAPER ADDS

What is already known on the subject Language development is dependent on basic cognitive processes. These include both verbal and non-verbal cognitive abilities. Children with LD often experience both language and cognitive problems. There is evidence that performance on cognitive tests may be associated with the degree of severity of LD. What this paper adds to existing knowledge The current results from a large population-based cohort establish that a number of verbal and non-verbal cognitive abilities are tightly linked to variation in language abilities and the degree of severity of LD. Our study confirms concurrent links between language and non-verbal cognitive abilities above and beyond the contribution of verbal cognitive abilities. We also identify specific verbal and non-verbal cognitive tests that distinguish between typical children and children with LD, as well as LD severity. What are the potential or actual clinical implications of this work? Our findings support the importance of measuring both verbal and non-verbal cognitive skills when making an LD diagnosis. Our findings also point to the potential of targeting underlying cognitive skills as one strategy to support language abilities. We suggest that future intervention studies focus on the impact of non-verbal cognitive skills on language development in children with LD.

Genome-wide analyses of individual differences in quantitatively assessed reading- and language-related skills in up to 34,000 people

The use of spoken and written language is a fundamental human capacity. Individual differences in reading- and language-related skills are influenced by genetic variation, with twin-based heritability estimates of 30 to 80% depending on the trait. The genetic architecture is complex, heterogeneous, and multifactorial, but investigations of contributions of single-nucleotide polymorphisms (SNPs) were thus far underpowered. We present a multicohort genome-wide association study (GWAS) of five traits assessed individually using psychometric measures (word reading, nonword reading, spelling, phoneme awareness, and nonword repetition) in samples of 13,633 to 33,959 participants aged 5 to 26 y. We identified genome-wide significant association with word reading (rs11208009, P = 1.098 × 10-8) at a locus that has not been associated with intelligence or educational attainment. All five reading-/language-related traits showed robust SNP heritability, accounting for 13 to 26% of trait variability. Genomic structural equation modeling revealed a shared genetic factor explaining most of the variation in word/nonword reading, spelling, and phoneme awareness, which only partially overlapped with genetic variation contributing to nonword repetition, intelligence, and educational attainment. A multivariate GWAS of word/nonword reading, spelling, and phoneme awareness maximized power for follow-up investigation. Genetic correlation analysis with neuroimaging traits identified an association with the surface area of the banks of the left superior temporal sulcus, a brain region linked to the processing of spoken and written language. Heritability was enriched for genomic elements regulating gene expression in the fetal brain and in chromosomal regions that are depleted of Neanderthal variants. Together, these results provide avenues for deciphering the biological underpinnings of uniquely human traits.

The co-occurrence of neurodevelopmental problems in dyslexia

The primary aim of this study was to explore the overlaps between dyslexia and a range of neurodevelopmental disorders and problems (NDPs), specifically symptoms of attention-deficit/hyperactivity disorder, autism spectrum disorder, atypical sensory perception and developmental coordination disorder. Capitalizing on a population-based sample of twins, secondary aims included estimating the heritability of dyslexia and reporting on the measurement characteristics of the scale used to assess dyslexia. A telephone interview regarding symptoms of dyslexia and other NDPs was conducted with parents of 1,688 nine-year-old twins. The prevalence and the heritability of dyslexia were estimated at 8 and 52%, respectively. The boy: girl ratio was 1.5:1. Results revealed that there was more than an eight-fold increase in (diagnostic proxy) NDPs prevalence in the dyslexia group as compared to typical readers. Quantitatively measured symptoms of inattention, oral language problems and atypical sensory perception significantly predicted dyslexia status in a multivariate analysis. By contrast, ASD-related inflexibility was inversely associated with dyslexia in the multivariate model. In sum, dyslexia often overlaps with other NDPs. The current study provides new knowledge supporting the position to move beyond isolated diagnostic categories into behavioural profiles of co-occurring problems when trying to understand the pattern of strengths and needs in individuals with dyslexia.

The development of phonological memory and language: A multiple groups approach

Pierce et al. (2017) have proposed that variations in the timing, quality and quantity of language input during the earliest stages of development are related to variations in the development of phonological working memory and, in turn, to later language learning outcomes. To examine this hypothesis, three groups of children who are at-risk for language learning were examined: children with cochlear implants (CI), children with developmental language disorder (DLD), and internationally-adopted (IA) children, Comparison groups of typically-developing monolingual (MON) children and second language (L2) learners were also included. All groups were acquiring French as a first or second language and were matched on age, gender, and socioeconomic status, as well as other group-specific factors; they were between 5;0-7;3 years of age at time of testing. The CI and DLD groups scored significantly more poorly on the memory measures than the other groups; while the IA and L2 groups did not differ from one another. While the IA group performed more poorly than the MON group, there was no difference between the L2 and MON groups. We also found differential developmental relationships between phonological memory and language among the groups of interest in comparison to the typically-developing MON and L2 groups supporting the hypothesis that language experiences early in life are consequential for language development because of their effects on the development of phonological memory.

Mentalising Moderates the Link between Autism Traits and Current Gender Dysphoric Features in Primarily Non-autistic, Cisgender Individuals

The co-occurrence between autism and gender dysphoria has received much attention recently. We found that, among 101 adults from the general population number of autism traits, as measured using the autism-spectrum quotient was associated significantly with recalled and current gender dysphoric traits. Furthermore, performance on an objective measure of mentalising, such as the “Reading the Mind in the Eyes” test was associated with current gender dysphoric traits, but most importantly it moderated the relation between number of autism traits and number of current gender dysphoric traits, such that the association was significant only when mentalising ability was relatively low. Results suggest mentalising may represent a contributing factor to the relation between autism and gender dysphoric traits in the general population.

A multi-group approach to examining language development in at-risk learners

A battery of standardized language tests and control measures was administered to three groups of at-risk language learners - internationally adopted children, deaf children with cochlear implants, and children with specific language impairment - and to groups of second-language learners and typically developing monolingual children. All children were acquiring French, were matched on age, gender, and socioeconomic status, and were between age 5;0 and 7;3 at the time of testing. Differences between the at-risk and not-at-risk groups were evident in all domains of language testing. The children with SLI or CIs scored significantly lower than the IA children and all three at-risk groups scored lower than the monolingual group; the L2 and IA groups scored similarly. The results suggest that children with limited access to, or ability to process, early language input are at greater risk than children with delayed input to an additional language but otherwise typical or relatively typical early input.

What Causes Specific Language Impairment in Children?

Specific language impairment (SLI) is diagnosed when a child's language development is deficient for no obvious reason. For many years, there was a tendency to assume that SLI was caused by factors such as poor parenting, subtle brain damage around the time of birth, or transient hearing loss. Subsequently it became clear that these factors were far less important than genes in determining risk for SLI. A quest to find “the gene for SLI” was undertaken, but it soon became apparent that no single cause could account for all cases. Furthermore, although fascinating cases of SLI caused by a single mutation have been discovered, in most children the disorder has a more complex basis, with several genetic and environmental risk factors interacting. The clearest evidence for genetic effects has come from studies that diagnosed SLI using theoretically motivated measures of underlying cognitive deficits rather than conventional clinical criteria.

Cognitive and familial risk evidence converged: A data-driven identification of distinct and homogeneous subtypes within the heterogeneous sample of reading disabled children

The evident degree of heterogeneity observed in reading disabled children has puzzled reading researchers for decades. Recent advances in the genetic underpinnings of reading disability have indicated that the heritable, familial risk for dyslexia is a major risk factor. The present data-driven, classification attempt aims to revisit the possibility of identifying distinct cognitive deficit profiles in a large sample of second to fourth grade reading disabled children. In this sample, we investigated whether genetic and environmental risk factors are able to distinguish between poor reader subtypes. In this profile, we included reading-related measures of phonemic awareness, letter-speech sound processing and rapid naming, known as candidate vulnerability markers associated with dyslexia and familial risk for dyslexia, as well as general cognitive abilities (non-verbal IQ and vocabulary). Clustering was based on a 200 multi-start K-means approach. Results revealed four emerging subtypes of which the first subtype showed no cognitive deficits underlying their poor reading skills (Reading-only impaired poor readers). The other three subtypes shared a core phonological deficit (PA) with a variable and discriminative expression across the other underlying vulnerability markers. More specific, type 2 showed low to poor performance across all reading-related and general cognitive abilities (general poor readers), type 3 showed a specific letter-speech sound mapping deficit next to a PA deficit (PA-LS specific poor readers) and type 4 showed a specific rapid naming deficit complementing their phonological weakness (PA-RAN specific poor readers). The first three poor reader profiles were more characterized by variable environmental risk factor, while the fourth, PA-RAN poor reader subtype showed a significantly strong familial risk for dyslexia. Overall, when we zoom in on the heterogeneous phenomenon of reading disability, unique and distinct cognitive subtypes can be identified, distinguishing between those poor readers more influences by the role of genes and those more influenced by environmental risk factors. Taking into account this diversity of distinct cognitive subtypes, instead of looking at the reading disabled sample as a whole, will help tailor future diagnostic and intervention efforts more specifically to the needs of children with such a specific deficit and risk pattern, as well as providing a more promising way forward for genetic studies of dyslexia.

What Factors Influence Language Impairment? Considering Resilience as well as Risk

The considerable variation observed in the profiles of children with language impairment (LI) raises challenges for the diagnosis, treatment and prevention of language difficulties, in particular since LI can present substantial issues calling for the investment of clinical, educational and public health resources. In this review paper, we examine biological, psychological and environmental factors that appear to influence the developmental course of LI. In this review paper we are interested not only in examining deficits and risk factors but also in identifying strengths of children with LI that can act as protective factors providing the child with a scaffold for more positive development and better outcomes.

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

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. (PsycINFO Database Record

Phonological memory and word learning deficits in children with specific language impairment: A role for perceptual context?

BACKGROUND

Sensitivity to perceptual context (anchoring) has been suggested to contribute to the development of both oral- and written-language skills, but studies of this idea in children have been rare.

AIMS

To determine whether deficient anchoring contributes to the phonological memory and word learning deficits of children with specific language impairment (SLI).

METHODS AND PROCEDURES

84 preschool children with and without SLI participated in the study. Anchoring to repeated items was evaluated in two tasks - a phonological memory task and a pseudo-word learning task.

OUTCOMES AND RESULTS

Compared to children with typical development, children with SLI had poorer phonological memory spans and learned fewer words during the word learning task. In both tasks the poorer performance of children with SLI reflected a smaller effect of anchoring that was manifested in a smaller effect of item repetition on performance. Furthermore, across the entire sample anchoring was significantly correlated with performance in vocabulary and grammar tasks.

CONCLUSIONS AND IMPLICATIONS

These findings are consistent with the hypothesis that anchoring contributes to language skills and that children with SLI have impaired anchoring, although further studies are required to determine the role of anchoring in language development.

Specific language impairment: a convenient label for whom?

BACKGROUND

The term 'specific language impairment' (SLI), in use since the 1980s, describes children with language impairment whose cognitive skills are within normal limits where there is no identifiable reason for the language impairment. SLI is determined by applying exclusionary criteria, so that it is defined by what it is not rather than by what it is. The recent decision to not include SLI in DSM-5 provoked much debate and concern from researchers and clinicians.

AIMS

To explore how the term 'specific language impairment' emerged, to consider how disorders, including SLI, are generally defined and to explore how societal changes might impact on use the term.

METHODS & PROCEDURES

We reviewed the literature to explore the origins of the term 'specific language impairment' and present published evidence, as well as new analyses of population data, to explore the validity of continuing to use the term.

OUTCOMES & RESULTS AND CONCLUSIONS & IMPLICATIONS

We support the decision to exclude the term 'specific language impairment' from DSM-5 and conclude that the term has been a convenient label for researchers, but that the current classification is unacceptably arbitrary. Furthermore, we argue there is no empirical evidence to support the continued use of the term SLI and limited evidence that it has provided any real benefits for children and their families. In fact, the term may be disadvantageous to some due to the use of exclusionary criteria to determine eligibility for and access to speech pathology services. We propose the following recommendations. First, that the word 'specific' be removed and the label 'language impairment' be used. Second, that the exclusionary criteria be relaxed and in their place inclusionary criteria be adopted that take into account the fluid nature of language development particularly in the preschool period. Building on the goodwill and collaborations between the clinical and research communities we propose the establishment of an international consensus panel to develop an agreed definition and set of criteria for language impairment. Given the rich data now available in population studies it is possible to test the validity of these definitions and criteria. Consultation with service users and policy-makers should be incorporated into the decision-making process.

Specific language impairment: a convenient label for whom?

BACKGROUND

The term 'specific language impairment' (SLI), in use since the 1980s, describes children with language impairment whose cognitive skills are within normal limits where there is no identifiable reason for the language impairment. SLI is determined by applying exclusionary criteria, so that it is defined by what it is not rather than by what it is. The recent decision to not include SLI in DSM-5 provoked much debate and concern from researchers and clinicians.

AIMS

To explore how the term 'specific language impairment' emerged, to consider how disorders, including SLI, are generally defined and to explore how societal changes might impact on use the term.

METHODS & PROCEDURES

We reviewed the literature to explore the origins of the term 'specific language impairment' and present published evidence, as well as new analyses of population data, to explore the validity of continuing to use the term.

OUTCOMES & RESULTS AND CONCLUSIONS & IMPLICATIONS

We support the decision to exclude the term 'specific language impairment' from DSM-5 and conclude that the term has been a convenient label for researchers, but that the current classification is unacceptably arbitrary. Furthermore, we argue there is no empirical evidence to support the continued use of the term SLI and limited evidence that it has provided any real benefits for children and their families. In fact, the term may be disadvantageous to some due to the use of exclusionary criteria to determine eligibility for and access to speech pathology services. We propose the following recommendations. First, that the word 'specific' be removed and the label 'language impairment' be used. Second, that the exclusionary criteria be relaxed and in their place inclusionary criteria be adopted that take into account the fluid nature of language development particularly in the preschool period. Building on the goodwill and collaborations between the clinical and research communities we propose the establishment of an international consensus panel to develop an agreed definition and set of criteria for language impairment. Given the rich data now available in population studies it is possible to test the validity of these definitions and criteria. Consultation with service users and policy-makers should be incorporated into the decision-making process.

Ten questions about terminology for children with unexplained language problems

BACKGROUND

In domains other than language, there is fairly consistent diagnostic terminology to refer to children's developmental difficulties. For instance, the terms 'dyslexia', 'attention deficit hyperactivity disorder' and 'autistic spectrum disorder' are used for difficulties with reading, attention or social cognition, respectively. There is no agreed label, however, for children with unexplained language problems.

AIMS

To consider whether we need labels for unexplained language problems in children, and if so, what terminology is appropriate.

MAIN CONTRIBUTION

There are both advantages and disadvantages to labels, but they are important to ensure children receive services, and to increase our knowledge of the nature and causes of such problems. A survey of labels in current use found 132 different terms, 33 of which had 600 or more returns on Google Scholar between 1994 and 2013. Many of these labels were too general to be useful. Of the remainder, the term 'specific language impairment' was the most commonly used.

CONCLUSIONS

The current mayhem in diagnostic labels is unsustainable; it causes confusion and impedes research progress and access to appropriate services. We need to achieve consensus on diagnostic criteria and terminology. The DSM-5 term 'language disorder' is problematic because it identifies too wide a range of conditions on an internet search. One solution is to retain specific language impairment, with the understanding that 'specific' means idiopathic (i.e., of unknown origin) rather than implying there are no other problems beyond language. Other options are the terms 'primary language impairment', 'developmental language disorder' or 'language learning impairment'.

When words fail us: insights into language processing from developmental and acquired disorders

Acquired disorders of language represent loss of previously acquired skills, usually with relatively specific impairments. In children with developmental disorders of language, we may also see selective impairment in some skills; but in this case, the acquisition of language or literacy is affected from the outset. Because systems for processing spoken and written language change as they develop, we should beware of drawing too close a parallel between developmental and acquired disorders. Nevertheless, comparisons between the two may yield new insights. A key feature of connectionist models simulating acquired disorders is the interaction of components of language processing with each other and with other cognitive domains. This kind of model might help make sense of patterns of comorbidity in developmental disorders. Meanwhile, the study of developmental disorders emphasizes learning and change in underlying representations, allowing us to study how heterogeneity in cognitive profile may relate not just to neurobiology but also to experience. Children with persistent language difficulties pose challenges both to our efforts at intervention and to theories of learning of written and spoken language. Future attention to learning in individuals with developmental and acquired disorders could be of both theoretical and applied value.

Articulating novel words: children's oromotor skills predict nonword repetition abilities

PURPOSE

Pronouncing a novel word for the first time requires the transformation of a newly encoded speech signal into a series of coordinated, exquisitely timed oromotor movements. Individual differences in children's ability to repeat novel nonwords are associated with vocabulary development and later literacy. Nonword repetition (NWR) is often used to test clinical populations. While phonological/auditory memory contributions to learning and pronouncing nonwords have been extensively studied, much less is known about the contribution of children's oromotor skills to this process.

METHOD

Two independent cohorts of children (7-13 years [N = 40] and 6.9-7.7 years [N = 37]) were tested on a battery of linguistic and nonlinguistic tests, including NWR and oromotor tasks.

RESULTS

In both cohorts, individual differences in oromotor control were a significant contributor to NWR abilities; moreover, in an omnibus analysis including experimental and standardized tasks, oromotor control predicted the most unique variance in NWR.

CONCLUSION

Results indicate that nonlinguistic oromotor skills contribute to children's NWR ability and suggest that important aspects of language learning and consequent language deficits may be rooted in the ability to perform complex sensorimotor transformations.

Psychophysical estimates of frequency discrimination: more than just limitations of auditory processing

Efficient auditory processing is hypothesized to support language and literacy development. However, behavioral tasks used to assess this hypothesis need to be robust to non-auditory specific individual differences. This study compared frequency discrimination abilities in a heterogeneous sample of adults using two different psychoacoustic task designs, referred to here as: 2I_6A_X and 3I_2AFC designs. The role of individual differences in nonverbal IQ (NVIQ), socioeconomic status (SES) and musical experience in predicting frequency discrimination thresholds on each task were assessed using multiple regression analyses. The 2I_6A_X task was more cognitively demanding and hence more susceptible to differences specifically in SES and musical training. Performance on this task did not, however, relate to nonword repetition ability (a measure of language learning capacity). The 3I_2AFC task, by contrast, was only susceptible to musical training. Moreover, thresholds measured using it predicted some variance in nonword repetition performance. This design thus seems suitable for use in studies addressing questions regarding the role of auditory processing in supporting language and literacy development.

[Abnormal electroencephalography results and specific language impairment: towards a theoretical neurodevelopmental model?]

BACKGROUND

Specific language impairment (SLI) is a primary developmental disorder in which language is significantly more impaired than other developmental domains. Abnormal electroencephalographic recordings without clinical seizures are often observed. The aim of this retrospective study was to characterize the frequency of these abnormalities, to describe them and to analyze their association with anamnestic, clinical, paraclinical and evolution characteristics.

METHODS

The cases of 35 children with a diagnosis of SLI, who also underwent electroencephalography and MRI, were systematically reviewed retrospectively.

RESULTS

In this population, aged between 4 and 7 years, 49% (n=17) of patients exhibited a specific expressive language disorder and 51% (n=18) a specific receptive disorder. Forty-nine percent of the children featured abnormal electroencephalography results. Abnormalities were essentially localized on the left side of the brain and in two specific regions: the temporo-occipital (60%) and the frontorolandic (30%) regions. The groups with and without abnormalities were compared statistically with each other in terms of clinical, paraclinical and evolution characteristics. Evolution data were available for 24 patients through a telephone interview and for nine patients through a new complete language evaluation. The comparison of the two groups showed significant differences in terms of severity of the phonological disorder, a higher number of delayed acquisition of walking and cleanliness and a higher range of non specific psychomotor difficulties.

DISCUSSION

A large proportion of children suffering from SLI present abnormal electroencephalography recordings with no clinical seizures. This rate is much higher than in the general population and the abnormalities are essentially localized on the left side of the brain in regions known for their specific role in language development. These abnormalities are more frequent in children with a severe phonological disorder, suggesting that they may share common pathophysiological features with SLI.

CONCLUSION

The presence of EEG abnormalities in a large group of patients suffering from SLI associated with minor neurological abnormalities suggests a possible theoretical neurodevelopmental model. Minor neurodevelopmental abnormalities, genetically transmitted or acquired during the pre- or perinatal period, may create vulnerability towards SLI. This vulnerability, in conjunction with environmental influences such as family environment, linguistic stimuli, exposure to multiple languages, or transitory hearing loss, might take the form of SLI. This hypothesis underlines the importance of prevention and early detection of SLI when identifying vulnerable subjects. Monitoring the family early through parental guidance and early school support would facilitate the acquisition of language.

Delayed retention of new word-forms is better in children than adults regardless of language ability: a factorial two-way study

Background

Nonword repetition, the ability to retain and repeat unfamiliar sequences of phonemes is usually impaired in children with specific language impairment (SLI), but it is unclear whether this explains slow language learning. Traditional nonword repetition tests involve a single presentation of nonwords for immediate repetition. Here we considered whether rate of learning of novel phonological sequences was impaired when the same items were presented repeatedly.

Methodology/Principal Findings

Three complex nonwords were each presented for repetition five times in two sessions (A and B) separated by one hour. We studied both adults and children from (i) families with a child with SLI and (ii) families whose children did not have SLI. This gave a 2×2 design with familial SLI as one factor, and age (up to or above 18 years) as the other. Overall, participants from families with SLI were poorer at nonword repetition than their peers from typical-language families, and there was a trend for children with SLI to show less within-session learning than typically developing children. However, between-session retention, measured as the difference between the last trial from session 1 and the first trial of session 2, showed a significant age effect, η² = .139, p = .004, regardless of family SLI status. Adult participants showed a decrease in score from the last trial of session A to the first trial of session B, whereas children maintained their level of performance, regardless of whether or not they had SLI.

Conclusions/Significance

Poor nonword repetition in SLI appears to reflect inadequate encoding of phonological information, rather than problems retaining encoded information. Furthermore, the nonword learning task is consistent with the notion of a sensitive period in language learning: Children show better retention over a delay for new phonological sequences than adults, regardless of overall level of language ability.

Auditory deficit as a consequence rather than endophenotype of specific language impairment: electrophysiological evidence

Background

Are developmental language disorders caused by poor auditory discrimination? This is a popular theory, but behavioural evidence has been inconclusive. Here we studied children with specific language impairment, measuring the brain’s electrophysiological response to sounds in a passive paradigm. We focused on the T-complex, an event-related peak that has different origins and developmental course from the well-known vertex response.

Methods

We analysed auditory event-related potentials to tones and syllables from 16 children and 16 adolescents with specific language impairment who were compared with 32 typically-developing controls, matched for gender, IQ and age.

Results

We replicated prior findings of significant reduction in Ta amplitude for both children and adolescents with specific language impairment, which was particularly marked for syllables. The topography of the T-complex to syllables indicated a less focal response in those with language impairments. To distinguish causal models, we considered correlations between size of the Ta response and measures of language and literacy in parents as well as children. The best-fitting model was one in which auditory deficit was a consequence rather than a cause of difficulties in phonological processing.

Conclusions

The T-complex to syllables has abnormal size and topography in children with specific language impairment, but this is more likely to be a consequence rather than a cause of difficulties in phonological processing.

Annual research review: the nature and classification of reading disorders--a commentary on proposals for DSM-5

This article reviews our understanding of reading disorders in children and relates it to current proposals for their classification in DSM-5. There are two different, commonly occurring, forms of reading disorder in children which arise from different underlying language difficulties. Dyslexia (as defined in DSM-5), or decoding difficulty, refers to children who have difficulty in mastering the relationships between the spelling patterns of words and their pronunciations. These children typically read aloud inaccurately and slowly, and experience additional problems with spelling. Dyslexia appears to arise principally from a weakness in phonological (speech sound) skills, and there is good evidence that it can be ameliorated by systematic phonic teaching combined with phonological awareness training. The other major form of reading difficulty is reading comprehension impairment. These children read aloud accurately and fluently, but have difficulty understanding what they have read. Reading comprehension impairment appears to arise from weaknesses in a range of oral language skills including poor vocabulary knowledge, weak grammatical skills and difficulties in oral language comprehension. We suggest that the omission of reading comprehension impairment from DSM-5 is a serious one that should be remedied. Both dyslexia and reading comprehension impairment are dimensional in nature, and show strong continuities with other disorders of language. We argue that recognizing the continuities between reading and language disorders has important implications for assessment and treatment, and we note that the high rates of comorbidity between reading disorders and other seemingly disparate disorders (including ADHD and motor disorders) raises important challenges for understanding these disorders.

A twin study of computer anxiety in Turkish adolescents

The present study investigated computer anxiety within a sample of Turkish twins aged 10-18. A total of 185 twin-pairs participated in the study. Of the twins, 64 pairs (34.6 percent) were monozygotic (MZ) and 121 pairs (65.4 percent) were dizygotic (DZ). Of the 121 DZ twins, 54 pairs (44.63 percent) were same-sex twins and 67 pairs (55.37 percent) were opposite-sex twins. Computer anxiety was assessed using Computer Anxiety Rating Scale-Turkish Version (CARS-TV), one of the three main scales of "Measuring Technophobia Instruments" developed by Rosen and Weil. The results of paired t test comparisons showed no significant differences in MZ and same-sex DZ twin-pairs' levels of computer anxiety. On the other hand, a significant difference was found in opposite-sex DZ twin-pairs' level of computer anxiety. Interesting enough, males appeared to be more computer anxious than their female co-twins. In the present study, using Falconer's formula, heritability estimate for computer anxiety was derived from correlations based on MZ and DZ twins' mean scores on CARS-TV. The results showed that 57 percent of the variance in computer anxiety was from genetics and 41.5 percent was from nonshared environmental factors. Shared environmental influence, on the other hand, was very small and negligible. Interpretations of results and potential directions for future research are presented.

Executive functioning in children with specific language impairment

BACKGROUND

A limited range of evidence suggests that children with specific language impairment (SLI) have difficulties with higher order thinking and reasoning skills (executive functioning, EF). This study involved a comprehensive investigation of EF in this population taking into account the contributions of age, nonverbal IQ and verbal ability.

METHODS

Ten separate measures of EF were assessed in 160 children: 41 had SLI; 31 had low language/cognitive functioning but did not fulfil the criteria for SLI (low language functioning or LLF); and 88 were typically developing with no language difficulties. Group differences in performance were assessed after controlling for age, nonverbal IQ and verbal ability in a series of regression analyses.

RESULTS

Children with SLI and LLF had significantly lower performance than typical children on 6 of the 10 EF tasks once age and nonverbal IQ had been controlled (verbal and nonverbal executive-loaded working memory, verbal and nonverbal fluency, nonverbal inhibition and nonverbal planning). Performance on these EF tasks remained lower for those in the SLI group even when verbal IQ was entered in the regressions.

CONCLUSIONS

Children with language impairments showed marked difficulties on a range of EF tasks. These difficulties were present even when adjustments were made for their verbal abilities.

The broader autism phenotype and its implications on the etiology and treatment of autism spectrum disorders

The presence of autism-related traits has been well documented in undiagnosed family members of individuals with autism spectrum disorder (ASD). The most common finding is mild impairments in social and communication skills that are similar to those shown by individuals with autism, but exhibited to a lesser degree. Termed the broader autism phenotype (BAP), these traits suggest a genetic liability for autism-related traits in families. Genetic influence in autism is strong, with identical twins showing high concordance for the diagnosis and related traits and approximately 20% of all ASD cases having an identified genetic mechanism. This paper highlights the studies conducted to date regarding the BAP and considers the implications of these findings for the etiology and treatment of ASD.

Time perception, phonological skills and executive function in children with dyslexia and/or ADHD symptoms

BACKGROUND

Deficits in time perception (the ability to judge the duration of time intervals) have been found in children with both attention-deficit/hyperactivity disorder (ADHD) and dyslexia. This paper investigates time perception, phonological skills and executive functions in children with dyslexia and/or ADHD symptoms (AS).

METHOD

Children with dyslexia-only (n = 17), AS-only (n = 17), comorbid dyslexia+AS (n = 25), and typically developing controls (n = 42), matched for age and non-verbal ability, were assessed on measures of phonological skills, executive function and time perception (duration discrimination and time reproduction).

RESULTS

Children with dyslexia were impaired on measures of phonological skill and duration discrimination compared to children without dyslexia (though problems on duration discrimination appeared to be attributable to mild symptoms of inattention in this group). In contrast, children with AS exhibited impairments on measures of both time perception and executive function compared to children without AS. Children with dyslexia+AS showed an additive combination of the deficits associated with dyslexia-only and AS-only.

CONCLUSIONS

Dyslexia and AS appear to be associated with distinct patterns of cognitive deficit, which are present in combination in children with dyslexia+AS.

Grammatical Difficulties in Children with Specific Language Impairment: Is Learning Deficient?

Theoretical accounts of grammatical limitations in specific language impairment (SLI) have been polarized between those that postulate problems with domain-specific grammatical knowledge, and those that regard grammatical deficits as downstream consequences of perceptual or memory limitations. Here we consider an alternative view that grammatical deficits arise when the learning system is biased towards memorization of exemplars, and is poor at extracting statistical dependencies from the input. We examine evidence that SLI involves deficits in extracting nonadjacent dependencies from input, leading to reliance on rote learning, and consider how far this may be part of a limitation of procedural learning, or a secondary consequence of memory limitations.

Intervention for mixed receptive-expressive language impairment: a review

Studies indicate that language impairment that cannot be accounted for by factors such as below-average non-verbal ability, hearing impairment, behaviour or emotional problems, or neurological impairments affects some 6% of school-age children. Language impairment with a receptive language component is more resistant to intervention than specific expressive or phonological delays, and carries a greater risk of comorbid behavioural difficulties as well as adverse outcomes for language development and academic progress. This paper considers underlying explanations that may account for receptive-expressive language impairment. It also reviews evidence for the effectiveness of intervention from theory and recent systematic reviews, trials, and speech and language therapy practice.

Inferior frontal gyrus activation predicts individual differences in perceptual learning of cochlear-implant simulations

This study investigated the neural plasticity associated with perceptual learning of a cochlear implant (CI) simulation. Normal-hearing listeners were trained with vocoded and spectrally shifted speech simulating a CI while cortical responses were measured with functional magnetic resonance imaging (fMRI). A condition in which the vocoded speech was spectrally inverted provided a control for learnability and adaptation. Behavioral measures showed considerable individual variability both in the ability to learn to understand the degraded speech, and in phonological working memory capacity. Neurally, left-lateralized regions in superior temporal sulcus and inferior frontal gyrus (IFG) were sensitive to the learnability of the simulations, but only the activity in prefrontal cortex correlated with interindividual variation in intelligibility scores and phonological working memory. A region in left angular gyrus (AG) showed an activation pattern that reflected learning over the course of the experiment, and covariation of activity in AG and IFG was modulated by the learnability of the stimuli. These results suggest that variation in listeners' ability to adjust to vocoded and spectrally shifted speech is partly reflected in differences in the recruitment of higher-level language processes in prefrontal cortex, and that this variability may further depend on functional links between the left inferior frontal gyrus and angular gyrus. Differences in the engagement of left inferior prefrontal cortex, and its covariation with posterior parietal areas, may thus underlie some of the variation in speech perception skills that have been observed in clinical populations of CI users.

A thirteen-year follow-up study of young Norwegian adults with dyslexia in childhood: reading development and educational levels

As part of a larger follow-up study, 75 students were diagnosed with dyslexia at 10 years of age. At the end of secondary school, grades for the whole cohort of 16-year olds were examined. At age 23 the whole study group responded to a questionnaire and the subgroup with dyslexia who responded to this questionnaire were invited to come for testing and interviews. The persistence of dyslexia into young adulthood and educational levels were examined. The results showed that almost all students still suffered dyslexia and showed lower decoding ability. However, they only showed slightly lower educational attainment levels compared with a representative sample of half the cohort (n=530) they were part of.

Atypical cerebral lateralisation in adults with compensated developmental dyslexia demonstrated using functional transcranial Doppler ultrasound

Functional transcranial Doppler ultrasound (fTCD) is a relatively new and non-invasive technique that assesses cerebral lateralisation through measurements of blood flow velocity in the middle cerebral arteries. In this study fTCD was used to compare functional asymmetry during a word generation task between a group of 30 dyslexic adults and a group of 30 non-dyslexic individuals. In light of previous evidence of atypical laterality in dyslexia, a reduced leftward asymmetry was predicted and confirmed. We know from previous research that most people with atypical language lateralisation have normal language and literacy skills: nevertheless, our results confirm that language laterality is reduced in those with dyslexia. Theoretical explanations for this apparent conundrum are discussed.

Supporting family adaptation to presymptomatic and "untreatable" conditions in an era of expanded newborn screening

OBJECTIVE

As technology advances, newborn screening will be possible for conditions not screened today. With an expansion of screening, strategies will be needed to support family adaptation to unexpected and possibly uncertain genetic information provided shortly after birth.

METHOD

Although candidate conditions for expanded newborn screening will typically be associated with increased morbidity or mortality, for most there is no proven medical treatment that must be implemented quickly. Many will have clinical features that gradually emerge and for which the severity of impact is not predictable. Parents will seek guidance on information, support, and treatment possibilities. This article summarizes issues evoked by expanded newborn screening and suggests strategies for supporting families of identified children.

RESULTS

We propose four components necessary to support family adaptation to pre-symptomatic and "untreatable" conditions in an era of expanded newborn screening: (1) accurate and understandable information; (2) formal and informal support; (3) active surveillance; and (4) general and targeted interventions. We argue that no condition is "untreatable" and that a well-designed program of prevention and support has the potential to maximize benefit and minimize harm.

CONCLUSIONS

Pediatric psychologists can play important roles in an era of expanded newborn screening by helping families understand genetic information, make informed decisions about genetic testing, and cope with the potential psychosocial consequences of genetic information.

Reading and subcortical auditory function

Although it is largely agreed that phonological processing deficits are a major cause of poor reading, the neural origins of phonological processing are not well understood. We now show, for the first time, that phonological decoding, measured with a test of single-nonword reading, is significantly correlated with the timing of subcortical auditory processing and also, to a lesser extent, with the robustness of subcortical representation of the harmonic content of speech, but not with pitch encoding. The relationships we observe between reading and subcortical processing fall along a continuum, with poor readers at one end and good readers at the other. These data suggest that reading skill may depend on the integrity of subcortical auditory mechanisms and are consistent with the idea that subcortical representation of the acoustic features of speech may play a role in normal reading as well as in the development of reading disorders. These data establish a significant link between subcortical auditory function and reading, thereby contributing to the understanding of the biological bases of reading. At a more general level, these findings are among the first to establish a direct relationship between subcortical sensory function and a specific cognitive skill (reading). We argue that this relationship between cortical and subcortical function could be shaped during development by the corticofugal pathway and that this cortical-subcortical link could contribute to the phonological processing deficits experienced by poor readers.

Genes, cognition, and communication: insights from neurodevelopmental disorders

Twin and family studies have demonstrated that most cognitive traits are moderately to highly heritable. Neurodevelopmental disorders such as dyslexia, autism, and specific language impairment (SLI) also show strong genetic influence. Nevertheless, it has proved difficult for researchers to identify genes that would explain substantial amounts of variance in cognitive traits or disorders. Although this observation may seem paradoxical, it fits with a multifactorial model of how complex human traits are influenced by numerous genes that interact with one another, and with the environment, to produce a specific phenotype. Such a model can also explain why genetic influences on cognition have not vanished in the course of human evolution. Recent linkage and association studies of SLI and dyslexia are reviewed to illustrate these points. The role of nonheritable genetic mutations (sporadic copy number variants) in causing autism is also discussed. Finally, research on phenotypic correlates of allelic variation in the genes ASPM and microcephalin is considered; initial interest in these as genes for brain size or intelligence has been dampened by a failure to find phenotypic differences in people with different versions of these genes. There is a current vogue for investigators to include measures of allelic variants in studies of cognition and cognitive disorders. It is important to be aware that the effect sizes associated with these variants are typically small and hard to detect without extremely large sample sizes.

Speaking genes or genes for speaking? Deciphering the genetics of speech and language

BACKGROUND

This article selectively reviews the status of the genetic research in the field of speech and language disorders.

METHODS

Major contributions to the field are selected, presented, and discussed.

RESULTS

The field presents itself through a variety of findings, characterized by both consistencies and inconsistencies.

CONCLUSIONS

The last 30 + years of the field unequivocally testify to the importance of genetic factors in the acquisition of speech and language. However, the details of how these factors exert their influence are yet to be determined.

What can autism and dyslexia tell us about intelligence?

This paper argues that understanding developmental disorders requires developing theories and models that explicitly represent the role of general intelligence in the cognitive phenotype of the disorder. In the case of autism it is argued that the low-IQ scores of people with autism are not likely to be due to a deficit in the cognitive process that is arguably the major cause of mental retardation - namely, speed of processing - but rather low IQ reflects the pervasive and cascading effects of the deficit in the information-processing module that causes autism. In the case of dyslexia, two radically different models of reading disorder (ability = disability and a modular deficit model) are likely to be influenced by the effect of general intelligence on reading performance in ways that will remain unclear without an explicit model of how general intelligence influences reading.

Speed of processing and reading disability: a cross-linguistic investigation of dyslexia and borderline intellectual functioning

English and Italian children with dyslexia were compared with children with reading difficulties associated with low-IQ on tests of simple and choice RT, and in number and symbol scanning tasks. On all four speed-of-processing tasks, children with low-IQ responded more slowly than children with dyslexia and age-controls. In the choice RT task, the performance of children with low-IQ was also less accurate than that of children of normal IQ, consistent with theories linking processing speed limitations with low-IQ. These findings support the hypothesis that dyslexia is a specific cognitive deficit that can arise in the context of normal IQ and normal speed of processing. The same cognitive phenotype was observed in readers of a deep (English) and a shallow (Italian) orthography.