Linguistic profile of individuals with Down syndrome: comparing the linguistic performance of three developmental disorders

[Formula: see text] Predicting language outcomes in bilingual children with Down syndrome

Continuous approaches to measuring bilingualism have recently emerged as a means of understanding individual variation in language abilities. To date, limited information is available to assist in understanding the language abilities of bilingual children with Down syndrome (DS), who are specifically known to have a large variation in linguistic outcomes. Group studies in this population report that children exposed to two languages do not differ from their monolingual counterparts after considering age and non-verbal cognitive abilities, although no study to date has examined the relationship between the amount of exposure to one language and the linguistic abilities in the other language within this population. This study sought to identify whether exposure to an additional language, specifically Welsh, predicted linguistic abilities in the majority language, in this case, English. Sixty-five children between the ages of 5;5-16;9 who had varied linguistic experiences completed a range of cognitive and linguistic assessments. Results from hierarchical regression analyses show that the amount of exposure to Welsh had no impact on language abilities in English, after controlling for non-verbal cognitive abilities, short-term memory and socioeconomic status. This demonstrates that exposure to an additional language does not have a negative impact on language development, a finding that has important clinical and educational implications.

Developmental Profile in Children Aged 3-6 Years: Down Syndrome vs. Autism Spectrum Disorder

This research aims to compare the developmental profiles of children with autism spectrum disorder (ASD) and children with Down Syndrome (DS) between the ages of 3 and 6 years. The study examines whether these developmental disorders share common developmental milestones or exhibit distinctive characteristics. A total of 43 children, 23 with DS and 20 with ASD, participated in the study. Cognitive and language skills were assessed using standardized tools, including the Battelle Developmental Inventory, Reynell Developmental Language Scales III, and NEPSY-II battery. The results indicated that children with ASD outperformed children with DS in the areas of fine motor skills, gross motor skills, and communication. Additionally, children with ASD demonstrated higher scores in language comprehension and expressive language, compared to children with DS. Significant correlations were found between motor skills and communication abilities. Neuropsychological evaluations revealed significant differences between the two groups in various tasks, such as the comprehension of instructions, body part naming and identification, and recognition of emotions. These findings contribute to our understanding of the similarities and differences between ASD and DS, shedding light on the dissociation between cognition and language and its impact on adaptive functioning in these populations.

Distinct neuroanatomical and neuropsychological features of Down syndrome compared to related neurodevelopmental disorders: a systematic review

Objectives

We critically review research findings on the unique changes in brain structure and cognitive function characteristic of Down syndrome (DS) and summarize the similarities and differences with other neurodevelopmental disorders such as Williams syndrome, 22q11.2 deletion syndrome, and fragile X syndrome.

Methods

We conducted a meta-analysis and systematic literature review of 84 studies identified by searching PubMed, Google Scholar, and Web of Science from 1977 to October 2022. This review focuses on the following issues: (1) specific neuroanatomic and histopathological features of DS as revealed by autopsy and modern neuroimaging modalities, (2) language and memory deficits in DS, (3) the relationships between these neuroanatomical and neuropsychological features, and (4) neuroanatomic and neuropsychological differences between DS and related neurodevelopmental syndromes.

Results

Numerous post-mortem and morphometric neuroimaging investigations of individuals with DS have reported complex changes in regional brain volumes, most notably in the hippocampal formation, temporal lobe, frontal lobe, parietal lobe, and cerebellum. Moreover, neuropsychological assessments have revealed deficits in language development, emotional regulation, and memory that reflect these structural changes and are more severe than expected from general cognitive dysfunction. Individuals with DS also show relative preservation of multiple cognitive, linguistic, and social domains compared to normally developed controls and individuals with other neurodevelopmental disorders. However, all these neurodevelopment disorders exhibit substantial heterogeneity among individuals.

Conclusion

People with Down syndrome demonstrate unique neurodevelopmental abnormalities but cannot be regarded as a homogenous group. A comprehensive evaluation of individual intellectual skills is essential for all individuals with neurodevelopment disorders to develop personalized care programs.

Bilingualism in children with a dual diagnosis of Down syndrome and Autism Spectrum Disorder

Research shows that a substantial proportion of children with Down syndrome (DS) also meet the clinical criteria for Autism Spectrum Disorder (ASD). Children with this dual diagnosis display a linguistic profile that includes significant language delays and language impairments which often differ from the impairments observed in each developmental disability (DD) separately. Given the challenges observed with language acquisition for children with DS-ASD, concerns might be raised regarding the outcomes and suitability of a bilingual environment for children with this dual diagnosis specifically. The aim of this research was to explore the language profiles of four children with DS-ASD. A multiple case-study approach was employed. Four children with a confirmed DS-ASD diagnosis who had received exposure to two languages (English and Welsh) were assessed on a range of cognitive and linguistic measures. Performance was compared to three control groups; bilinguals with DS, English monolinguals with DS and mental age-matched typically developing bilinguals. Assessments comprised of expressive and receptive language, phonological awareness, working memory and non-verbal cognitive abilities. Considerable variability was found in the cognitive and linguistic profiles of the case-study participants. Children with DS-ASD displayed similar language profiles to that of the bilingual and monolingual children with DS in the areas tested, although performance was generally lower than that of the TD bilingual children. Although substantial variability was found, participants were developing bilingual abilities in a similar trajectory to children with DS in line with the degree of exposure to each language. This research highlights the need to assess bilingual children with complex dual diagnoses with an individualistic approach and carefully consider how to appropriately assess and treat bilingual children within speech and language therapy provisions.

Communication in Angelman syndrome: a scoping review

AIM

A scoping review was conducted to examine and evaluate empirical data on the communication profile of Angelman syndrome beyond the described dissociation between receptive language and speech.

METHOD

Three databases (PsycINFO, Embase, and Web of Science) were searched to retrieve articles investigating communication in Angelman syndrome. Seventeen articles investigating the broader communication profile were found; their methodology was evaluated against quality criteria.

RESULTS

Despite the absence of speech, individuals with Angelman syndrome have a wide repertoire of non-verbal communicative behaviours, mainly characterized by gestures, although advanced forms such as symbolic communication are used by some individuals. The use of communicative forms differs between the genetic aetiologies of Angelman syndrome; individuals with non-deletion aetiologies typically have greater communicative abilities.

INTERPRETATION

The broader communication profile of Angelman syndrome is characterized by diverse and multimodal abilities, including some use of symbolic forms of communication that appears atypical given the absence of speech. This is suggestive of a probable dissociation between speech and other expressive forms of communication, indicating an isolated speech production impairment. This highlights a need in this population for alternative communication and specific input from services tailored to support the nuances of the communication profile of Angelman syndrome.

WHAT THIS PAPER ADDS

Although absent speech is near universal, a diverse profile of other communicative abilities has been reported. Parental reporting has been predominantly used to assess the communication profile of Angelman syndrome. Literature that investigates the specificities and possible dissociations in such a communication profile is limited.

Auditory-Perceptual Speech Features in Children With Down Syndrome

Speech disorders occur commonly in individuals with Down syndrome (DS), although data regarding the auditory-perceptual speech features are limited. This descriptive study assessed 47 perceptual speech features during connected speech samples in 26 children with DS. The most severely affected speech features were: naturalness, imprecise consonants, hyponasality, speech rate, inappropriate silences, irregular vowels, prolonged intervals, overall loudness level, pitch level, aberrant oropharyngeal resonance, hoarse voice, reduced stress, and prolonged phonemes. These findings suggest that speech disorders in DS are due to distributed impairments involving voice, speech sound production, fluency, resonance, and prosody. These data contribute to the development of a profile of impairments in speakers with DS to guide future research and inform clinical assessment and treatment.

Does the Development of Syntax Comprehension Show a Premature Asymptote Among Persons With Down Syndrome? A Cross-Sectional Analysis

Uncertainty persists regarding the post-childhood trajectory of syntactic acquisition of persons with Down syndrome (DS). In some studies, asymptote is reached in the early teens, whereas others find syntax continuing to develop at least into early adulthood. This study addressed the issue using a cross-sectional approach. Receptive syntax and vocabulary were tested in 62 children, adolescents and young adults with DS matched on chronological age and cognitive level with 62 participants with intellectual disability (ID) of undifferentiated etiology. On both tests there were significant effects of chronological age and diagnosis, but the chronological age × diagnosis interactions were nonsignificant. We concluded that comprehension of vocabulary and syntax does not asymptote prematurely in individuals with DS relative to those with other forms of ID.

Parent-mediated interventions for promoting communication and language development in young children with Down syndrome

BACKGROUND

Communication and language development are areas of particular weakness for young children with Down syndrome. Caregivers' interaction with children influences language development, so many early interventions involve training parents how best to respond to their children and provide appropriate language stimulation. Thus, these interventions are mediated through parents, who in turn are trained and coached in the implementation of interventions by clinicians. As the interventions involve a considerable commitment from clinicians and families, we undertook this review to synthesise the evidence of their effectiveness.

OBJECTIVES

To assess the effects of parent-mediated interventions for improving communication and language development in young children with Down syndrome. Other outcomes are parental behaviour and responsivity, parental stress and satisfaction, and children's non-verbal means of communicating, socialisation and behaviour.

SEARCH METHODS

In January 2018 we searched CENTRAL, MEDLINE, Embase and 14 other databases. We also searched three trials registers, checked the reference lists of relevant reports identified by the electronic searches, searched the websites of professional organizations, and contacted their staff and other researchers working in the field to identify other relevant published, unpublished and ongoing studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs that compared parent-mediated interventions designed to improve communication and language versus teaching/treatment as usual (TAU) or no treatment or delayed (wait-listed) treatment, in children with Down syndrome aged between birth and six years. We included studies delivering the parent-mediated intervention in conjunction with a clinician-mediated intervention, as long as the intervention group was the only group to receive the former and both groups received the latter.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures for data collection and analysis.

MAIN RESULTS

We included three studies involving 45 children aged between 29 months and six years with Down syndrome. Two studies compared parent-mediated interventions versus TAU; the third compared a parent-mediated plus clinician-mediated intervention versus a clinician-mediated intervention alone. Treatment duration varied from 12 weeks to six months. One study provided nine group sessions and four individualised home-based sessions over a 13-week period. Another study provided weekly, individual clinic-based or home-based sessions lasting 1.5 to 2 hours, over a six-month period. The third study provided one 2- to 3-hour group session followed by bi-weekly, individual clinic-based sessions plus once-weekly home-based sessions for 12 weeks. Because of the different study designs and outcome measures used, we were unable to conduct a meta-analysis.We judged all three studies to be at high risk of bias in relation to blinding of participants (not possible due to the nature of the intervention) and blinding of outcome assessors, and at an unclear risk of bias for allocation concealment. We judged one study to be at unclear risk of selection bias, as authors did not report the methods used to generate the random sequence; at high risk of reporting bias, as they did not report on one assessed outcome; and at high risk of detection bias, as the control group had a cointervention and only parents in the intervention group were made aware of the target words for their children. The sample sizes of each included study were very small, meaning that they are unlikely to be representative of the target population.The findings from the three included studies were inconsistent. Two studies found no differences in expressive or receptive language abilities between the groups, whether measured by direct assessment or parent reports. However, they did find that children in the intervention group could use more targeted vocabulary items or utterances with language targets in certain contexts postintervention, compared to those in the control group; this was not maintained 12 months later. The third study found gains for the intervention group on total-language measures immediately postintervention.One study did not find any differences in parental stress scores between the groups at any time point up to 12 months postintervention. All three studies noted differences in most measures of how the parents talked to and interacted with their children postintervention, and in one study most strategies were maintained in the intervention group at 12 months postintervention. No study reported evidence of language attrition following the intervention in either group, while one study found positive outcomes on children's socialisation skills in the intervention group. One study looked at adherence to the treatment through attendance data, finding that mothers in the intervention group attended seven out of nine group sessions and were present for four home visits. No study measured parental use of the strategies outside of the intervention sessions.A grant from the Hospital for Sick Children Foundation (Toronto, Ontario, Canada) funded one study. Another received partial funding from the National Institute of Child Health and Human Development and the Department of Education in the USA. The remaining study did not specify any funding sources.In light of the serious limitations in methodology, and the small number of studies included, we considered the overall quality of the evidence, as assessed by GRADE, to be very low. This means that we have very little confidence in the results, and further research is very likely to have an important impact on our confidence in the estimate of treatment effect.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to determine the effects of parent-mediated interventions for improving the language and communication of children with Down syndrome. We found only three small studies of very low quality. This review highlights the need for well-designed studies, including RCTs, to evaluate the effectiveness of parent-mediated interventions. Trials should use valid, reliable and similar measures of language development, and they should include measures of secondary outcomes more distal to the intervention, such as family well-being. Treatment fidelity, in particular parental dosage of the intervention outside of prescribed sessions, also needs to be documented.

Inference From Facial Expressions Among Adolescents and Young Adults With Down Syndrome

The focus of this study was the ability of adolescents and young adults with Down syndrome to infer meaning from facial expressions in the absence of emotion labels and use this inference in order to adjust their behavior. Participants with Down syndrome ( N = 19, mean nonverbal mental age of 5.8 years) and 4- to 7-year-old typically developing children performed a novel task in which happy and angry faces were provided as feedback for a choice made by the participants. In making a subsequent choice, the participants with Down syndrome performed similarly to the 4 year olds, indicating a difficulty using angry faces as feedback. Individual differences within the group were also apparent. Implications for the development of social competence are discussed.

Evaluation of the language profile in children with rolandic epilepsy and developmental dysphasia: Evidence for distinct strengths and weaknesses

Although benign, rolandic epilepsy (RE) or benign childhood epilepsy with centro-temporal spikes is often associated with language impairment. Recently, fronto-rolandic EEG abnormalities have been described in children with developmental dysphasia (DD), suggesting an interaction between language impairment and interictal epileptiform discharges. To investigate if a behavioral-linguistic continuum between RE and DD exists, a clinical prospective study was carried out to evaluate the language profile of 15 children with RE and 22 children with DD. Language skills were assessed using an extensive, standardized test battery. Language was found to be impaired in both study groups, however RE and DD were associated with distinct language impairment profiles. Children with RE had difficulties with sentence comprehension, semantic verbal fluency and auditory short-term memory, which are unrelated to age of epilepsy onset and laterality of epileptic focus. In children with DD, sentence comprehension and verbal fluency were among their relative strengths, whereas sentence and lexical production constituted relative weaknesses.

Consideração da idade mental na avaliação do vocabulário expressivo de crianças com Síndrome de Down

RESUMO Objetivo: verificar vocabulário expressivo de crianças com Síndrome de Down, comparar ao desempenho de crianças com desenvolvimento típico de mesmo gênero em dois pareamentos distintos: considerando idade cronológica e mental, separadamente, e determinar a influência da idade considerada na avaliação desta população. Métodos: cumpriram-se aspectos éticos. Participaram 14 com Síndrome de Down, idade cronológica entre 38 a 63 meses, 14 com desenvolvimento típico pareado por gênero e idade mental e 14 com desenvolvimento típico pareado por gênero e idade cronológica. Após entrevista, aplicou-se Teste de Linguagem Infantil ABFW-Vocabulário Parte B. Para pareamento da idade mental utilizou-se o teste Stanford Binet. Aplicação do teste paramétrico ANOVA, teste Kruskal-Walis e Teste Tukey, quando necessário. Resultados: verificou-se desempenho inferior das crianças com Síndrome de Down comparadas ao grupo pareado por idade cronológica para nomeação correta e não nomeação das figuras. Não houve diferença significante entre o grupo com Síndrome de Down e com desenvolvimento típico pareado por idade mental. Conclusão: as crianças com Síndrome de Down apresentaram vocabulário expressivo aquém do esperado para a idade cronológica, porém próximo ao esperado para a idade mental, permitindo inferir que a idade considerada na avaliação da linguagem desta população interfere na análise dos resultados encontrados.

Variable White Matter Atrophy and Intellectual Development in a Family With X-linked Creatine Transporter Deficiency Despite Genotypic Homogeneity

BACKGROUND

The X-linked creatine transporter deficiency (CRTD) caused by an SLC6A8 mutation represents the second most common cause of X-linked intellectual disability. The clinical phenotype ranges from mild to severe intellectual disability, epilepsy, short stature, poor language skills, and autism spectrum disorders. The objective of this study was to investigate phenotypic variability in the context of genotype, cerebral creatine concentration, and volumetric analysis in a family with CRTD.

PATIENTS AND METHODS

The clinical phenotype and manifestations of epilepsy were assessed in a Caucasian family with CRTD. DNA sequencing and creatine metabolism analysis confirmed the diagnosis. Cerebral magnetic resonance imaging (cMRI) with voxel-based morphometry and magnetic resonance spectroscopy was performed in all family members.

RESULTS

An SLC6A8 missense mutation (c.1169C>T; p.Pro390Leu, exon 8) was detected in four of five individuals. Both male siblings were hemizygous, the mother and the affected sister heterozygous for the mutation. Structural cMRI was normal, whereas voxel-based morphometry analysis showed reduced white matter volume below the first percentile of the reference population of 290 subjects in the more severely affected boy compared with family members and controls. Normalized creatine concentration differed significantly between the individuals (P < 0.005).

CONCLUSIONS

There is a broad phenotypic variability in CRTD even in family members with the same mutation. Differences in mental development could be related to atrophy of the subcortical white matter.

Attention allocation to facial expressions of emotion among persons with Williams and Down syndromes

Individuals with Williams syndrome and those with Down syndrome are both characterized by heightened social interest, although the manifestation is not always similar. Using a dot-probe task, we examined one possible source of difference: allocation of attention to facial expressions of emotion. Thirteen individuals with Williams syndrome (mean age = 19.2 years, range = 10-28.6), 20 with Down syndrome (mean age = 18.8 years, range = 12.1-26.3), and 19 typically developing children participated. The groups were matched for mental age (mean = 5.8 years). None of the groups displayed a bias to angry faces. The participants with Williams syndrome showed a selective bias toward happy faces, whereas the participants with Down syndrome behaved similarly to the typically developing participants with no such bias. Homogeneity in the direction of bias was markedly highest in the Williams syndrome group whose bias appeared to result from enhanced attention capture. They appeared to rapidly and selectively allocate attention toward positive facial expressions. The complexity of social approach behavior and the need to explore other aspects of cognition that may be implicated in this behavior in both syndromes is discussed.

Motor, linguistic, personal and social aspects of children with Down syndrome

A global developmental delay is expected from Down syndrome, affecting motor, cognitive, linguistic and personal-social skills. However, not always these delays are proportional; different conditions occur due to several intrinsic and extrinsic variables that must be controlled to form groups of greater homogeneity.

A cross-syndrome study of the differential effects of sleep on declarative memory consolidation in children with neurodevelopmental disorders

Sleep plays an active role in memory consolidation. Because children with Down syndrome (DS) and Williams syndrome (WS) experience significant problems with sleep and also with learning, we predicted that sleep‐dependent memory consolidation would be impaired in these children when compared to typically developing (TD) children. This is the first study to provide a cross‐syndrome comparison of sleep‐dependent learning in school‐aged children. Children with DS (n = 20) and WS (n = 22) and TD children (n = 33) were trained on the novel Animal Names task where they were taught pseudo‐words as the personal names of ten farm and domestic animals, e.g. Basco the cat, with the aid of animal picture flashcards. They were retested following counterbalanced retention intervals of wake and sleep. Overall, TD children remembered significantly more words than both the DS and WS groups. In addition, their performance improved following night‐time sleep, whereas performance over the wake retention interval remained stable, indicating an active role of sleep for memory consolidation. Task performance of children with DS did not significantly change following wake or sleep periods. However, children with DS who were initially trained in the morning continued to improve on the task at the following retests, so that performance on the final test was greater for children who had initially trained in the morning than those who trained in the evening. Children with WS improved on the task between training and the first retest, regardless of whether sleep or wake occurred during the retention interval. This suggests time‐dependent rather than sleep‐dependent learning in children with WS, or tiredness at the end of the first session and better performance once refreshed at the start of the second session, irrespective of the time of day. Contrary to expectations, sleep‐dependent learning was not related to baseline level of performance. The findings have significant implications for educational strategies, and suggest that children with DS should be taught more important or difficult information in the morning when they are better able to learn, whilst children with WS should be allowed a time delay between learning phases to allow for time‐dependent memory consolidation, and frequent breaks from learning so that they are refreshed and able to perform at their best.

Syntactic comprehension and working memory in children with specific language impairment, autism or Down syndrome

This study examined syntactic assignment for predicates and reflexives as well as working memory effects in the sentence comprehension of children with Specific Language Impairment (SLI), Down syndrome (DS), high functioning Autism (HFA) and Typical Language Development (TLD). Fifty-seven children (35 boys and 22 girls) performed a computerised picture-selection sentence comprehension task. Predicate attachment and reflexive antecedent assignment (with working memory manipulations) were investigated. The results showed that SLI, HFA and DS children exhibited poorer overall performance than TLD children. Children with SLI exhibited similar performance to the DS and HFA children only when working memory demands were higher. We conclude that children with SLI, HFA and DS differ from children with TLD in their comprehension of predicate and reflexive structures where the knowledge of syntactic assignment is required. Working memory manipulation had different effects on syntactic comprehension depending on language disorder. Intelligence was not an explanatory factor for the differences observed in performance.

Receptive vocabulary and semantic knowledge in children with SLI and children with Down syndrome

Receptive vocabulary and associated semantic knowledge were compared within and between groups of children with specific language impairment (SLI), children with Down syndrome (DS), and typically developing children. To overcome the potential confounding effects of speech or language difficulties on verbal tests of semantic knowledge, a novel task was devised based on picture-based semantic association tests used to assess adult patients with semantic dementia. Receptive vocabulary, measured by word-picture matching, of children with SLI was weak relative to chronological age and to nonverbal mental age but their semantic knowledge, probed across the same lexical items, did not differ significantly from that of vocabulary-matched typically developing children. By contrast, although receptive vocabulary of children with DS was a relative strength compared to nonverbal cognitive abilities (p < .0001), DS was associated with a significant deficit in semantic knowledge (p < .0001) indicative of dissociation between word-picture matching vocabulary and depth of semantic knowledge. Overall, these data challenge the integrity of semantic-conceptual development in DS and imply that contemporary theories of semantic cognition should also seek to incorporate evidence from atypical conceptual development.

Early hearing loss and language abilities in children with Down syndrome

BACKGROUND

Although many children with Down syndrome experience hearing loss, there has been little research to investigate its impact on speech and language development. Studies that have investigated the association give inconsistent results. These have often been based on samples where children with the most severe hearing impairments have been excluded and so results do not generalize to the wider population with Down syndrome. Also, measuring children's hearing at the time of a language assessment does not take into account the fluctuating nature of hearing loss in children with Down syndrome or possible effects of losses in their early years.

AIMS

To investigate the impact of early hearing loss on language outcomes for children with Down syndrome.

METHODS & PROCEDURES

Retrospective audiology clinic records and parent report for 41 children were used to categorize them as either having had hearing difficulties from 2 to 4 years or more normal hearing. Differences between the groups on measures of language expression and comprehension, receptive vocabulary, a narrative task and speech accuracy were investigated.

OUTCOMES & RESULTS

After accounting for the contributions of chronological age and nonverbal mental age to children's scores, there were significant differences between the groups on all measures.

CONCLUSIONS & IMPLICATIONS

Early hearing loss has a significant impact on the speech and language development of children with Down syndrome. Results suggest that speech and language therapy should be provided when children are found to have ongoing hearing difficulties and that joint audiology and speech and language therapy clinics could be considered for preschool children.

Context modulates attention to social scenes in toddlers with autism

BACKGROUND

In typical development, the unfolding of social and communicative skills hinges upon the ability to allocate and sustain attention toward people, a skill present moments after birth. Deficits in social attention have been well documented in autism, though the underlying mechanisms are poorly understood.

METHODS

In order to parse the factors that are responsible for limited social attention in toddlers with autism, we manipulated the context in which a person appeared in their visual field with regard to the presence of salient social (child-directed speech and eye contact) and nonsocial (distractor toys) cues for attention. Participants included 13- to 25-month-old toddlers with autism (autism; n = 54), developmental delay (DD; n = 22), and typical development (TD; n = 48). Their visual responses were recorded with an eye-tracker.

RESULTS

In conditions devoid of eye contact and speech, the distribution of attention between key features of the social scene in toddlers with autism was comparable to that in DD and TD controls. However, when explicit dyadic cues were introduced, toddlers with autism showed decreased attention to the entire scene and, when they looked at the scene, they spent less time looking at the speaker's face and monitoring her lip movements than the control groups. In toddlers with autism, decreased time spent exploring the entire scene was associated with increased symptom severity and lower nonverbal functioning; atypical language profiles were associated with decreased monitoring of the speaker's face and her mouth.

CONCLUSIONS

While in certain contexts toddlers with autism attend to people and objects in a typical manner, they show decreased attentional response to dyadic cues for attention. Given that mechanisms supporting responsivity to dyadic cues are present shortly after birth and are highly consequential for development of social cognition and communication, these findings have important implications for the understanding of the underlying mechanisms of limited social monitoring and identifying pivotal targets for treatment.

A qualitative analysis of general receptive vocabulary of adolescents with Down syndrome

This study aimed to discover whether general receptive vocabulary is qualitatively phenotypical in Down syndrome. Sixty-two participants with Down syndrome (M age=16.74 years, SD=3.28) were individually matched on general vocabulary raw total score with 62 participants with intellectual disability of undifferentiated etiology (M age=16.20 years, SD=3.08) and 62 typical children (M age=5.32 years, SD=0.82). Item analyses using the transformed item difficulties method to detect differential item functioning across groups showed that the groups' rank orders of item difficulty were highly similar. It was concluded that the general receptive vocabulary of older children and adolescents with Down syndrome is not qualitatively distinguished when its overall size is held constant. Methodological and theoretical implications of this finding are discussed.

Processing of facial expressions of emotions by adults with Down syndrome and moderate intellectual disability

The processing of facial expressions of emotions by 23 adults with Down syndrome and moderate intellectual disability was compared with that of adults with intellectual disability of other etiologies (24 matched in cognitive level and 26 with mild intellectual disability). Each participant performed 4 tasks of the Florida Affect Battery and an original task in which they had to match facial expressions after observing the complete face or one of its halves. Adults with Down syndrome did not show any specific difficulties in recognizing facial expressions in spite of showing a poorer discrimination between facial expressions and tended to take more notice of the lower half of the face.

Comparação do léxico de crianças com Síndrome de Down e com desenvolvimento típico de mesma idade mental

OBJETIVO: verificar o desempenho lexical, receptivo e expressivo, de crianças com Síndrome de Down e comparar com o desempenho lexical de crianças com desenvolvimento típico pareados por sexo e idade mental. MÉTODO: participaram do estudo 40 crianças, 20 com síndrome de Down (grupo experimental - GE), de ambos os sexos, com idade cronológica variando entre 36 e 71 meses e 20 crianças com desenvolvimento típico (grupo controle - GC) pareadas quanto ao sexo e idade mental (avaliação psicológica com o instrumento Nova Versão do Método Stanford-Binet, adaptado por Terman e Merril) com o GE. Após a assinatura do Termo de Consentimento Livre e Esclarecido pelos responsáveis legais, estes responderam um protocolo de anamnese, contendo informações sobre a vida pregressa do participante. A avaliação foi composta pela aplicação do Teste de Vocabulário por Imagens Peabody (TVIP), que avalia vocabulário receptivo, e do Teste de Linguagem Infantil ABFW - Vocabulário Parte B, que avalia vocabulário expressivo. RESULTADOS: os participantes do GE apresentaram desempenho inferior ao GC no TVIP e na designação verbal usual do ABFW, com diferenças estatisticamente significantes. Verificou-se correlação entre o desempenho no vocabulário receptivo e expressivo de ambos os grupos. CONCLUSÃO: verificou-se que o desempenho lexical, receptivo e expressivo, das crianças com SD é inferior ao de crianças com desenvolvimento típico, mesmo quando pareadas pela idade mental.

Language disorder with mild intellectual disability in a child affected by a novel mutation of SLC6A8 gene

We describe the clinical and molecular features of a child harboring a novel mutation in SLC6A8 gene in association with a milder phenotype than other creatine transporter (CT1) deficient patients (OMIM 300352) [1-7]. The mutation c.757 G>C p.G253R in exon 4 of SLC6A8 was hemizygous in the child, aged 6 years and 6 months, who showed mild intellectual disability with severe speech and language delay. His carrier mother had borderline intellectual functioning. Although the neurochemical and biochemical parameters were fully consistent with those reported in the literature for subjects with CT1 deficit, in our patient within a general cognitive disability, a discrepancy between nonverbal and verbal skills was observed, confirming the peculiar vulnerability of language development under brain Cr depletion.

A puzzle form of a non-verbal intelligence test gives significantly higher performance measures in children with severe intellectual disability

BACKGROUND

Assessment of 'potential intellectual ability' of children with severe intellectual disability (ID) is limited, as current tests designed for normal children do not maintain their interest. Thus a manual puzzle version of the Raven's Coloured Progressive Matrices (RCPM) was devised to appeal to the attentional and sensory preferences and language limitations of children with ID. It was hypothesized that performance on the book and manual puzzle forms would not differ for typically developing children but that children with ID would perform better on the puzzle form.

METHODS

The first study assessed the validity of this puzzle form of the RCPM for 76 typically developing children in a test-retest crossover design, with a 3 week interval between tests. A second study tested performance and completion rate for the puzzle form compared to the book form in a sample of 164 children with ID.

RESULTS

In the first study, no significant difference was found between performance on the puzzle and book forms in typically developing children, irrespective of the order of completion. The second study demonstrated a significantly higher performance and completion rate for the puzzle form compared to the book form in the ID population.

CONCLUSION

Similar performance on book and puzzle forms of the RCPM by typically developing children suggests that both forms measure the same construct. These findings suggest that the puzzle form does not require greater cognitive ability but demands sensory-motor attention and limits distraction in children with severe ID. Thus, we suggest the puzzle form of the RCPM is a more reliable measure of the non-verbal mentation of children with severe ID than the book form.