Étude du style interactif maternel et des compétences sociocommunicatives des enfants. Une étude comparative entre enfants porteurs de trisomie et enfants typiques

The goal is to explain Down syndrome social language disturbances. Down's syndrome and non-handicapped children were observed interacting with their mothers. We compared 22 dyads with Down syndrome children and 22 dyads with non-handicapped children. Down's syndrome children were matched on mental age with non-handicapped children (4 to 24 months). Social context, mothers' behaviours and children's social communicative competences were evaluated. Interaction behaviours in the mothers of DS children differ from those of mothers of non-handicapped children. DS communicative competences also are different from those in non-handicapped children. We argue that mothers' behavioural interaction in the dyads with DS children can be an aspect of social communicative disturbances of DS children.     

Attention in Williams syndrome and Down's syndrome: Performance on the new early childhood attention battery

Attentional problems are commonly reported as a feature of the behavioural profile in both Williams syndrome (WS) and Down's syndrome (DS). Recent studies have begun to investigate these impairments empirically, acknowledging the need for an approach that considers cross‐syndrome comparisons and developmental changes across the different component functions of attention. The present study assessed children with WS and DS using a new preschool attention battery (ECAB: early childhood attention battery), designed to be suitable for mental age 3–6 years including groups with developmental disorders. The ECAB has the advantage of giving an individual profile of attentional abilities for each child, covering different components of attention. In relation to test norms for their mental age, both groups showed a profile of strengths and weaknesses in the attention domain. Both syndrome groups performed relatively well on tests of sustained attention and poorly on aspects of selective attention and attentional control (executive function). The DS group showed a specific strength in auditory sustained attention, whilst the WS group showed a particular deficit in visuo‐spatial response control. There was also evidence for considerable differences in the developmental trajectory of these abilities across the two groups. The results provide evidence for syndrome‐specific patterns of impairment, and distinct profiles of strengths and weaknesses that may be useful in understanding the nature of everyday attention difficulties in these groups and tailoring interventions to meet these needs.     

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.     

Learning by observation and learning by doing in Down and Williams syndromes

New skills may be learned by active experience (experiential learning or learning by doing) or by observation of others’ experience (learning by observation). In general, learning by observation reduces the time and the attempts needed to learn complex actions and behaviors. The present research aimed to compare learning by observation and learning by doing in two clinical populations with different etiology of intellectual disability (ID), as individuals with Down syndrome (DS) and individuals with Williams syndrome (WS), with the hypothesis that specific profiles of learning may be found in each syndrome. To this end, we used a mixture of new and existing data to compare the performances of 24 individuals with DS, 24 individuals with WS and 24 typically developing children on computerized tasks of learning by observation or learning by doing. The main result was that the two groups with ID exhibited distinct patterns of learning by observation. Thus, individuals with DS were impaired in reproducing the previously observed visuo‐motor sequence, while they were as efficient as TD children in the experiential learning task. On the other hand, individuals with WS benefited from the observational training while they were severely impaired in detecting the visuo‐motor sequence in the experiential learning task (when presented first). The present findings reinforce the syndrome‐specific hypothesis and the view of ID as a variety of conditions in which some cognitive functions are more disrupted than others because of the differences in genetic profile and brain morphology and functionality. These findings have important implications for clinicians, who should take into account the genetic etiology of ID in developing learning programs for treatment and education.     

Global dot integration in typically developing children and in Williams Syndrome

Williams Syndrome (WS) is a neurodevelopmental disorder that results in deficits in visuospatial perception and cognition. The dorsal stream vulnerability hypothesis in WS predicts that visual motion processes are more susceptible to damage than visual form processes. We asked WS participants and typically developing children to detect the global structure Glass patterns, under “static” and “dynamic” conditions in order to evaluate this hypothesis. Sequentially presented Glass patterns are coined as dynamic because they induce illusory motion, which is modeled after the interaction between orientation (form) and direction (motion) mechanisms. If the dorsal stream vulnerability holds in WS participants, then they should process real and illusory motion atypically. However, results are consistent with the idea that form and motion integration mechanisms are functionally delayed or attenuated in WS. Form coherence thresholds for both static and dynamic Glass patterns in WS were similar to those of 4–5 year old children, younger than what is predicted by mental age. Dynamic presentation of Glass patterns improved thresholds to the same degree as typical participants. Motion coherence thresholds in WS were similar to those of mental age matches. These data pose constraints on the dorsal vulnerability hypothesis, and refine our understanding of the relationship between form and motion processing in development.     

Global dot integration in typically developing children and in Williams Syndrome

Williams Syndrome (WS) is a neurodevelopmental disorder that results in deficits in visuospatial perception and cognition. The dorsal stream vulnerability hypothesis in WS predicts that visual motion processes are more susceptible to damage than visual form processes. We asked WS participants and typically developing children to detect the global structure Glass patterns, under “static” and “dynamic” conditions in order to evaluate this hypothesis. Sequentially presented Glass patterns are coined as dynamic because they induce illusory motion, which is modeled after the interaction between orientation (form) and direction (motion) mechanisms. If the dorsal stream vulnerability holds in WS participants, then they should process real and illusory motion atypically. However, results are consistent with the idea that form and motion integration mechanisms are functionally delayed or attenuated in WS. Form coherence thresholds for both static and dynamic Glass patterns in WS were similar to those of 4–5 year old children, younger than what is predicted by mental age. Dynamic presentation of Glass patterns improved thresholds to the same degree as typical participants. Motion coherence thresholds in WS were similar to those of mental age matches. These data pose constraints on the dorsal vulnerability hypothesis, and refine our understanding of the relationship between form and motion processing in development.     

Play and emotional availability in young children with Down syndrome

This study investigates mother–child interaction and its associations with play in children with Down syndrome (DS). There is consensus that mother–child interaction during play represents an important determinant of typical children's play development. Concerning children with DS, few studies have investigated mother–child interaction in terms of the overall emotional quality of dyadic interaction and its effect on child play. A sample of 28 children with DS (M age = 3 years) took part in this study. In particular, we studied whether the presence of the mother in an interactional context affects the exploratory and symbolic play of children with DS and the interrelation between children's level of play and dyadic emotional availability. Children showed significantly more exploratory play during collaborative play with mothers than during solitary play. However, the maternal effect on child symbolic play was higher in children of highly sensitive mothers relative to children whose mothers showed lower sensitivity, the former displaying more symbolic play than the latter in collaborative play. Results offer some evidence that dyadic emotional availability and child play level are associated in children with DS, consistent with the hypothesis that dyadic interactions based on a healthy level of emotional involvement may lead to enhanced cognitive functioning.     

Egocentric and allocentric navigation strategies in Williams syndrome and typical development

Recent findings suggest that difficulties on small‐scale visuospatial tasks documented in Williams syndrome (WS) also extend to large‐scale space. In particular, individuals with WS often present with difficulties in allocentric spatial coding (encoding relationships between items within an environment or array). This study examined the effect of atypical spatial processing in WS on large‐scale navigational strategies, using a novel 3D virtual environment. During navigation of recently learnt large‐scale space, typically developing (TD) children predominantly rely on the use of a sequential egocentric strategy (recalling the sequence of left–right body turns throughout a route), but become more able to use an allocentric strategy between 5 and 10 years of age. The navigation strategies spontaneously employed by TD children between 5 and 10 years of age and individuals with WS were analysed. The ability to use an allocentric strategy on trials where spatial relational knowledge was required to find the shortest route was also examined. Results showed that, unlike TD children, during spontaneous navigation the WS group did not predominantly employ a sequential egocentric strategy. Instead, individuals with WS followed the path until the correct environmental landmarks were found, suggesting the use of a time‐consuming and inefficient view‐matching strategy for wayfinding. Individuals with WS also presented with deficits in allocentric spatial coding, demonstrated by difficulties in determining short‐cuts when required and difficulties developing a mental representation of the environment layout. This was found even following extensive experience in an environment, suggesting that – unlike in typical development – experience cannot contribute to the development of spatial relational processing in WS. This atypical presentation of both egocentric and allocentric spatial encoding is discussed in relation to specific difficulties on small‐scale spatial tasks and known atypical cortical development in WS.     

Developmental trajectories for spatial frames of reference in Williams syndrome

Williams syndrome (WS) is a genetic disorder associated with severe visuocognitive impairment. Individuals with WS also report difficulties with everyday wayfinding. To study the development of body-, environment-, and object-based spatial frames of reference in WS, we tested 45 children and adults with WS on a search task in which the participant and a spatial array are moved with respect to each other. Although individuals with WS showed a marked delay, like young controls they demonstrated independent, additive use of body- and environment-based frames of reference. Crucially, object-based (intrinsic) representations based on local landmarks within the array were only marginally used even by adults with WS, whereas in typical development these emerge at 5 years. Deficits in landmark use are consistent with wayfinding difficulties in WS, and may also contribute to problems with basic localization, since in typical development landmark-based representations supplement those based on the body and on self-motion. Difficulties with inhibition or mental rotation may be further components in the impaired ability to use the correct reference frame in WS.     

Learning to read in children with Williams syndrome

People with Williams syndrome are characterized by linguistic abilities that are higher than their level of intelligence. There is controversy concerning their reading level because there are few studies. The aim of this work was to test reading abilities in a group of school-age children with Williams syndrome. Their performance was contrasted with a control group of the same mental age. Three kinds of tasks were used: word and pseudoword reading, phonological awareness, and naming speed. Results show that the Williams syndrome children performed similarly to control children in reading accuracy but were slower in reading words and pseudowords. They were also slower in the naming speed tasks. These results suggest that Williams syndrome children do not have difficulties in developing grapheme-phoneme decoding but do present some difficulties in developing lexical reading.     

Prehension in young children with Down syndrome

Prehension was examined in 3-year old children with Down syndrome (DS, n = 3) and in typically-developing children matched in chronological age (3-year olds; n = 3) or mental age and motor experience (2-year olds; n = 3). The task required reaching to grasp dowels. Video-based movement analysis yielded temporal and kinematic measures. Children with DS were hypothesized to have deficits in feedback-dependent components of prehension (anticipatory grip-closure and deceleration of reach), whereas feedforward components (reach's acceleration phase; grasp's preshaping) were assumed to be unimpaired [Latash, 1993, Control of human movement, pp. 283-292; Latash, 1994, What is clumsiness? In: Motor Control and Down Syndrome II Proceedings of the second international conference, pp. 68-71]. The findings supported these hypotheses. In comparison to control groups, children with DS had significantly: (a) less time in deceleration of reaching, (b) fewer anticipatory grip-closures, and (c) longer movement times for dowel-lift. Young children with DS appeared to use dowel-contact to decelerate the limb and initiate grip-closure. In contrast, reach-acceleration time and grasp-preshaping did not differ across groups. These findings suggest that children with DS display qualitative differences in motor capabilities rather than simply a delayed rate of typical developmental progression.     

Numerical magnitude processing impairments in genetic syndromes: a cross‐syndrome comparison of Turner and 22q11.2 deletion syndromes

Cross‐syndrome comparisons offer an important window onto understanding heterogeneity in mathematical learning disabilities or dyscalculia. The present study therefore investigated symbolic numerical magnitude processing in two genetic syndromes that are both characterized by mathematical learning disabilities: Turner syndrome and 22q11.2 deletion syndrome (22q11DS). We further verified whether the phenotypic outcomes of these syndromes emerged from the same or different cognitive processes and therefore examined whether numerical impairments were related to working memory deficits, often observed in these syndromes. Participants were 24 girls with Turner syndrome, 25 children with 22q11DS and 48 well‐matched typically developing control children. All children completed a symbolic numerical magnitude comparison task and four additional working memory tasks. Both groups of children with genetic syndromes showed similar impairments in symbolic numerical magnitude processing compared to typically developing controls. Importantly, in Turner syndrome, group differences in symbolic numerical magnitude processing disappeared when their difficulties in visual‐spatial working memory were taken into account. In contrast, the difficulties in 22q11DS were not explained by poor visual‐spatial working memory. These data suggest that different factors underlie the symbolic numerical magnitude processing impairments in both patient groups with mathematical learning disabilities and highlight the value of cross‐syndrome comparisons for understanding different pathways to mathematical learning disabilities or dyscalculia.     

Développement des capacités sociolinguistiques chez des enfants et adolescents porteurs de trisomie 21 et étude de l'environnement sociolinguistique maternel

The aim of our research is to understand the language disturbances in Down syndrome children. Several studies demonstrated substantial differences between sociolanguage behaviours of mothers' Down syndrome children and those of mothers of non retarded children. We propose that these differences can explain DS language disturbances. So, we have compared 12 mother-child dyads (4 Down syndrome children are from 8 to 9 years, 4 are from 12 to 13 years and 4 are from 16 to 17 years). Dyads play in tutorial interaction. Results show language abilities evolution for Down syndrome subjects. Nevertheless, mothers' sociolanguage behaviors do no change.     

Music and Language Skills of Children with Williams Syndrome

We examined music and language abilities in a group of children with Williams syndrome (WS, n = 19) and a comparison group of normal children (n = 19) equivalent for receptive vocabulary. Consistent with previous reports and the model of Nonverbal Learning Disabilities (Rourke, 1989), the children with WS scored better on verbal than performance measures of the WISC-III, and performance on simpler verbal tasks (e.g., receptive vocabulary) was superior to performance on more complex verbal tasks (e.g., comprehension). Performance on music tests was relatively good, being comparable to mental age based on receptive vocabulary and similar to that of the comparison group. Music and language abilities were moderately correlated for both groups of children. Compared to normal children, the WS group expressed greater liking of music and a greater range of emotional responses to music.     

Facial emotion recognition in Williams syndrome and Down syndrome: A matching and developmental study

In this study both the matching and developmental trajectories approaches were used to clarify questions that remain open in the literature on facial emotion recognition in Williams syndrome (WS) and Down syndrome (DS). The matching approach showed that individuals with WS or DS exhibit neither proficiency for the expression of happiness nor specific impairments for negative emotions. Instead, they present the same pattern of emotion recognition as typically developing (TD) individuals. Thus, the better performance on the recognition of positive compared to negative emotions usually reported in WS and DS is not specific of these populations but seems to represent a typical pattern. Prior studies based on the matching approach suggested that the development of facial emotion recognition is delayed in WS and atypical in DS. Nevertheless, and even though performance levels were lower in DS than in WS, the developmental trajectories approach used in this study evidenced that not only individuals with DS but also those with WS present atypical development in facial emotion recognition. Unlike in the TD participants, where developmental changes were observed along with age, in the WS and DS groups, the development of facial emotion recognition was static. Both individuals with WS and those with DS reached an early maximum developmental level due to cognitive constraints.     

Expressive drawing ability in children with autism

The autistic impairments in emotional and social competence, imagination and generating ideas predict qualitative differences in expressive drawings by children with autism beyond that accounted by any general learning difficulties. In a sample of 60 5–19‐year‐olds, happy and sad drawings were requested from 15 participants with non‐savant autism and compared with those drawn by three control groups matched on either degree of learning difficulty (MLD), mental age (MA) or chronological age (CA). All drawings were rated by two artists on a 7‐point quality of expression scale. Contrary to our predictions, the drawings from the autistic group were rated similar to those of the MA and MLD groups. Analysis of the people and social content of the drawings revealed that although children with autism did not draw fewer people, they did draw more immature forms than mental age controls. Furthermore, there was tentative evidence that fewer social scenes were produced by the autism sample. We conclude that the overall merit of expressive drawing in autism is commensurate with their general learning difficulties, but the social/emotional impairment in autism affects their drawings of people and social scenes.     

Spoken and gestural production in a naming task by young children with Down syndrome

Lexical production in children with Down syndrome (DS) was investigated by examining spoken naming accuracy and the use of spontaneous gestures in a picture naming task. Fifteen children with DS (range 3.8-8.3 years) were compared to typically developing children (TD), matched for chronological age and developmental age (range 2.6-4.3 years). Relative to TD children, children with DS were less accurate in speech (producing a greater number of unintelligible answers), yet they produced more gestures overall and of these a significantly higher percentage of iconic gestures. Furthermore, the iconic gestures produced by children with DS accompanied by incorrect or no speech often expressed a concept similar to that of the target word, suggesting deeper conceptual knowledge relative to that expressed only in speech.     

L'accord grammatical de genre dans la dysphasie de développement

Various studies report that children with Specific Language Impairment (SLI) have important difficulties in using grammatical morphemes expressing gender, number or tense but none of these studies let us determine whether agreement perception is impaired. To answer this question, 18 children with SLI and 18 control children without language impairment participated in two tasks testing production and perception of French gender agreement between determiner and noun. The results showed that (i) only children with SLI produced gender errors or determiner omissions whereas (ii) both groups were sensitive to agreement violations: they were slower and made more errors to categorize disagreeing determiner phrases (*the_[masc] banana_[fem]).     

L'interprétation d'indices non verbaux par les enfants

Interpreting appropriately face expressions and analyzing social relations between people, according to their actions are useful competence for treating pragmatic aspects of communication. We do research on these competences by presenting a recognition emotion task, and a task in which movements of geometrical figures simulate social interaction, to 98 children (children aged 8, 10, 12 and 14 years, children with autism and mental retardation). Results show that answers qualitatively increase with age, even after 12 years. Children with autism encounter more difficulties to recognize emotional expression than to attribute intentional actions. Emotion recognition is related to simple intention attribution but not with complex one, which develops later.     

Mathematical skill in individuals with Williams syndrome: evidence from a standardized mathematics battery

Williams syndrome (WS) is a developmental disorder associated with relatively spared verbal skills and severe visuospatial deficits. It has also been reported that individuals with WS are impaired at mathematics. We examined mathematical skills in persons with WS using the second edition of the Test of Early Mathematical Ability (TEMA-2), which measures a wide range of skills. We administered the TEMA-2 to 14 individuals with WS and 14 children matched individually for mental-age on the matrices subtest of the Kaufman Brief Intelligence Test. There were no differences between groups on the overall scores on the TEMA-2. However, an item-by-item analysis revealed group differences. Participants with WS performed more poorly than controls when reporting which of two numbers was closest to a target number, a task thought to utilize a mental number line subserved by the parietal lobe, consistent with previous evidence showing parietal abnormalities in people with WS. In contrast, people with WS performed better than the control group at reading numbers, suggesting that verbal math skills may be comparatively strong in WS. These findings add to evidence that components of mathematical knowledge may be differentially damaged in developmental disorders.