Language and communication development in Down syndrome

Although there is considerable variability, most individuals with Down syndrome have mental retardation and speech and language deficits, particularly in language production and syntax and poor speech intelligibility. This article describes research findings in the language and communication development of individuals with Down syndrome, first briefly describing the physical and cognitive phenotype of Down syndrome, and two communication related domains-hearing and oral motor skills. Next, we describe language development in Down syndrome, focusing on communication behaviors in the prelinguistic period, then the development of language in children and adolescents, and finally language development in adults and the aging period. We describe language development in individuals with Down syndrome across four domains: phonology, semantics, syntax, and pragmatics. Wethen suggest strategies for intervention and directions for research relating to individuals with Down syndrome.     

Lexico-semantic processing in Williams syndrome

People with Williams syndrome, a neurodevelopmental genetic syndrome, typically have good language skills as compared to other cognitive abilities, as far as intellectual disability is concerned. They have a large vocabulary and they frequently use uncommon or rarely-used words. This has led some authors to consider that they have a peculiar semantic system, different from that of people with typical development. In this study, we tested this hypothesis by comparing the performance of a group of young adults with Williams syndrome to a control group using various lexico-semantic tasks, including semantic and phonological fluency. The results indicate that the semantic system of people with Williams syndrome does not seem to differ much from those in the control group because the words they produced were similar to those of the control group with regard to word frequency, length or the typicality of the responses within the categories.     

Fading-figure tracing in Williams syndrome

Williams syndrome (WS) is a neurodevelopmental disorder characterized by severe impairment of visuospatial abilities. Figure-drawing abilities, which are thought to reflect visuospatial abilities, have yet to be fully investigated in WS. The purpose of the present study was to clarify whether drawing abilities differ between WS individuals and typically developing children (TD). We compared the performance of two groups of subjects (WS, mean age 16 years; TD, 5-6 years of age) using a fading-figure tracing task that requires subjects to trace a target figure that is gradually disappearing from a PC screen. Although the TD group exhibited clearly improved performance with long fading time, the WS group did not. Moreover, the TD group exhibited poor performance for figures with more than six angles, regardless of the figure type (e.g. closed or open), whereas the WS group exhibited generally poor performance for figures with more than five angles but relatively preserved performance for open figures. These findings indicate that a combination of decreased visuospatial span associated with incomplete development of visual scanning and disproportionate development of global processing may cause drawing disabilities in WS.     

Exploring face perception in disorders of development: Evidence from Williams syndrome and autism

Individuals with Williams syndrome (WS) and autism are characterized by different social phenotypes but have been said to show similar atypicalities of face‐processing style. Although the structural encoding of faces may be similarly atypical in these two developmental disorders, there are clear differences in overall face skills. The inclusion of both populations in the same study can address how the profile of face skills varies across disorders. The current paper explored the processing of identity, eye‐gaze, lip‐reading, and expressions of emotion using the same participants across face domains. The tasks had previously been used to make claims of a modular structure to face perception in typical development. Participants with WS (N=15) and autism (N=20) could be dissociated from each other, and from individuals with general developmental delay, in the domains of eye‐gaze and expression processing. Individuals with WS were stronger at these skills than individuals with autism. Even if the structural encoding of faces appears similarly atypical in these groups, the overall profile of face skills, as well as the underlying architecture of face perception, varies greatly. The research provides insights into typical and atypical models of face perception in WS and autism.     

Inflectional morphology in German Williams syndrome

In a recent paper, Clahsen and Almazan (1998) reported a dissociation between unimpaired regular and impaired irregular past tense morphology in English Williams syndrome (WS). Our aim is to investigate whether these findings carry over to another language with different morphological systems. We present data on regular and irregular participles and noun plurals from 2 German WS subjects and 10 controls matching in mental age. For noun plurals, regular morphology is intact in WS, whereas irregular forms are impaired. A similar dissociation is observed for participles: while regular inflection is unimpaired, WS subjects, unlike controls, apply the regular suffix incorrectly to frequent irregular verbs. We discuss our findings against the current debate between connectionist and dualistic approaches to the language faculty.     

The Williams syndrome cognitive profile

Williams syndrome is a rare neurodevelopmental disorder caused by a hemizygous deletion of approximately 1.5 megabases on chromosome 7q11.23. In this article, we outline a Williams Syndrome Cognitive Profile (WSCP) that operationalizes the cognitive characteristics of the syndrome using measures of absolute and relative performance on subtests of the Differential Abilities Scales (Elliot, 1990a). Testing confirmed excellent sensitivity and specificity scores for the WSCP. Seventy-four of 84 individuals with Williams syndrome fit the WSCP while only 4 participants in a contrast group met all of the WSCP criteria. It was also found that the WSCP does not vary greatly with chronological age or overall level of cognitive ability for individuals with Williams syndrome. Possible applications for the WSCP include psychoeducational evaluation and empirical research such as the search for genotype/phenotype relations in this genetically based syndrome.     

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.     

Attentional disengagement in adults with Williams syndrome

Williams syndrome (WS) is a neurodevelopmental disorder characterized by a distinctive behavioral and cognitive profile, including widespread problems with attention. However, the specific nature of their attentional difficulties, such as inappropriate attentional allocation and/or poor attentional disengagement abilities, has yet to be elucidated. Furthermore, it is unknown if there is an underlying difficulty with the temporal dynamics of attention in WS or if their attentional difficulties are task-dependent, because previous studies have examined attention in established areas of deficit and atypicality (specifically, visuospatial and face processing). In this study, we examined attentional processing in 14 adults with WS (20–59 years) and 17 typically developing controls (19–39 years) using an attentional blink (AB) paradigm. The AB is the decreased ability to detect a second target when it is presented in close proximity to an initial target. Overall, adults with WS had an AB that was prolonged in duration, but no different in magnitude, compared with typically developing control participants. AB performance was not explained by IQ, working memory, or processing speed in either group. Thus, results suggest that the attention problems in WS are primarily due to general attentional disengagement difficulties rather than inappropriate attentional allocation.     

A cross-syndrome study of the development of holistic face recognition in children with autism, Down syndrome, and Williams syndrome

We report a cross-syndrome comparison of the development of holistic processing in face recognition in school-aged children with developmental disorders: autism, Down syndrome, and Williams syndrome. The autism group was split into two groups: one with high-functioning children and one with low-functioning children. The latter group has rarely been studied in this context. The four disorder groups were compared with typically developing children. Cross-sectional trajectory analyses were used to compare development in a modified version of Tanaka and Farah’s part–whole task. Trajectories were constructed linking part–whole performance either to chronological age or to several measures of mental age (receptive vocabulary, visuospatial construction, and the Benton Facial Recognition Test). In addition to variable delays in onset and rate of development, we found an atypical profile in all disorder groups. These profiles were atypical in different ways, indicating multiple pathways to, and variable outcomes in, the development of face recognition. We discuss the implications for theories of face recognition in both atypical and typical development, including the idea that part–whole and rotation manipulations may tap different aspects of holistic and/or configural processing.     

Behavioural indexes of callosal functioning in Williams syndrome

Williams syndrome (WS) is a neurogenetic disorder that stems from a microdeletion on chromosome 7. Recent anatomical studies have found evidence for corpus callosum abnormalities in WS. However, to date, the impact of these structural differences on callosal functionality remains unclear. The aim of the present study was to investigate interhemispheric communication and hemispheric asymmetry in individuals with WS relative to mental age‐matched controls. This was assessed using bilateral and unilateral presentations of visual stimuli in a picture‐naming task. Results found both groups to exhibit a bilateral field advantage and a left visual advantage on unilateral presentations. However, while a significant performance increase with age was found for controls, no such correlation was found for individuals with WS. Taken together, these findings suggest that despite some evidence for an atypical developmental pathway in WS, both interhemispheric communication and hemispheric asymmetry are functionally intact in this population.     

Small Subitizing Range in People with Williams syndrome

Recent evidence suggests that the rapid apprehension of small numbers of objects-- often called subitizing-- engages a system which allows representation of up to 4 objects but is distinct from other aspects of numerical processing. We examined subitizing by studying people with Williams syndrome (WS), a genetic deficit characterized by severe visuospatial impairments, and normally developing children (4-6.5 years old). In Experiment 1, participants first explicitly counted displays of 1 to 8 squares that appeared for 5 s and reported "how many". They then reported "how many" for the same displays shown for 250 ms, a duration too brief to allow explicit counting, but sufficient for subitizing. All groups were highly accurate up to 8 objects when they explicitly counted. With the brief duration, people with WS showed almost perfect accuracy up to a limit of 3 objects, comparable to 4 year-olds but fewer than either 5 or 6.5 year-old children. In Experiment 2, participants were asked to report "how many" for displays that were presented for an unlimited duration, as rapidly as they could while remaining accurate. Individuals with WS responded as rapidly as 6.5 year-olds, and more rapidly than 4 year-olds. However, their accuracy was as in Experiment 1, comparable to 4 year-olds, and lower than older children. These results are consistent with previous results indicating that people with WS can simultaneously represent multiple objects, but that they have a smaller capacity than older children, on par with 4 year-olds. This pattern is discussed in the context of normal and abnormal development of visuospatial skills, in particular those linked to the representation of numerosity.     

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.     

Nature and nurture: Williams syndrome across cultures

This study is concerned with ways in which children with Williams syndrome (WS), a rare neurodevelopmental disorder arising from a hemizygous deletion in chromosome band 7q11.23 including the gene for elastin (ELN) and approximately 20 surrounding genes, are affected by social mores of vastly differing cultures: the United States and Japan. WS presents a compelling model for the investigation because its genetic phenotype is well defined and results in an uneven cognitive profile as well as a social phenotype typical of the syndrome including overt over-friendliness toward strangers. While a number of research groups have been studying the cognitive strengths and weaknesses of individuals with WS in various countries, there have not been studies to date that explore the social phenotype in WS across different cultures. This study examines the ways in which social behavior in WS, stemming from specific genetic underpinnings, might be mediated by cultural expectations. We conducted a cross-cultural study using an instrument that measures aspects of sociability commonly found among people with WS. Quantitative analyses revealed a significant effect of diagnostic category in that in both countries, children with WS were rated as significantly higher in global sociability and more likely to approach strangers than were their normal counterparts. There was also an effect of culture, in that regardless of category, WS and normal children in Japan were rated lower than their counterparts in the US. We suggest that the excessively social phenotype of children with Williams syndrome, although markedly present across cultures, appears to vary in its intensity by culture. This is an intriguing illustration of interactions between nature and nurture.     

Drawing the line: Drawing and construction strategies for simple and complex figures in Williams syndrome and typical development

In the typical population, a series of drawing strategies have been outlined, which progressively emerge during childhood. Individuals with Williams syndrome (WS), a rare genetic disorder, produce drawings that lack cohesion, yet drawing strategies in this group have hitherto not been investigated. In this study, WS and typically developing (TD) groups drew and constructed (from pre‐drawn lines and shapes) a series of intersecting and embedded figures. Participants with WS made use of the same strategies as the TD group for simple intersecting figures, though were less likely to use a typical strategy for more complex figures that contained many spatial relations. When replicating embedded shapes, the WS group used typical drawing strategies less frequently than the TD group, despite attempting to initiate a strategy that is observed in TD children. Results suggested that individuals with WS show a particular difficulty with replicating figures that include multiple spatial relations. The impact of figure complexity and task demands on performance are discussed.     

Language and imitation in development

Noting the central role accorded imitation in the origins of symbolic functioning, language development, and identity formation, as well as its relationship to aspects of individuation, the authors have reviewed the problem of imitation from both cognitive developmental and psychoanalytic perspectives. They have specifically delineated piagetian views regarding the origins of imitation and traced its relationship to the emergence of language, while attempting to clarify various psychoanalytic formulations on this topic. This dual theoretical perspective is then reconsidered within the framework of the current empirical infancy literature. Pathological sequelae of imitation are also reviewed in relation to their impact upon ego formation and the process of socialization. Tracing a cognitive developmental line, the authors then discuss the relationship between imitation and the emergence of language; language is also considered as an important vehicle of communication which furthers and enhances ego development and object relations. The authors conclude with a partial integration of piagetian and psychoanalytic hypotheses regarding imitation and identity formation with the aim of stimulating further discussion on this topic.     

Active music classes in infancy enhance musical, communicative and social development

Previous studies suggest that musical training in children can positively affect various aspects of development. However, it remains unknown as to how early in development musical experience can have an effect, the nature of any such effects, and whether different types of music experience affect development differently. We found that random assignment to 6 months of active participatory musical experience beginning at 6 months of age accelerates acquisition of culture-specific knowledge of Western tonality in comparison to a similar amount of passive exposure to music. Furthermore, infants assigned to the active musical experience showed superior development of prelinguistic communicative gestures and social behaviour compared to infants assigned to the passive musical experience. These results indicate that (1) infants can engage in meaningful musical training when appropriate pedagogical approaches are used, (2) active musical participation in infancy enhances culture-specific musical acquisition, and (3) active musical participation in infancy impacts social and communication development.     

People with Williams syndrome process faces holistically

This study compared the performance of 47 adolescents and adults with Williams syndrome to 39 age-matched controls on a face recognition task. Using the whole-part paradigm developed by Tanaka and his colleagues, we found that although performance overall was lower in the participants with Williams syndrome, both groups showed similar patterns of performance across the different conditions. Both groups performed significantly better in the whole-face than in the isolated-part test condition for upright faces, but not for inverted faces. The whole-face advantage only in the upright condition provides strong evidence that people with Williams syndrome encode and recognize faces holistically in the same way as normal controls, suggesting the use of similar underlying neurocognitive mechanisms. These findings contradict earlier reports in the literature that people with Williams syndrome process faces abnormally.     

Visually guided step descent in children with Williams syndrome

Individuals with Williams syndrome (WS) have impairments in visuospatial tasks and in manual visuomotor control, consistent with parietal and cerebellar abnormalities. Here we examined whether individuals with WS also have difficulties in visually controlling whole-body movements. We investigated visual control of stepping down at a change of level in children with WS (5-16-year-olds), who descended a single step while their movement was kinematically recorded. On each trial step height was set unpredictably, so that visual information was necessary to perceive the step depth and position the legs appropriately before landing. Kinematic measures established that children with WS did not use visual information to slow the leg at an appropriate point during the step. This pattern contrasts with that observed in typically developing 3- and 4-year-old children, implying severe impairment in whole-body visuomotor control in WS. For children with WS, performance was not significantly predicted by low-level visual or balance problems, but improved significantly with verbal age. The results suggest some plasticity and development in WS whole-body control. These data clearly show that visuospatial and visuomotor deficits in WS extend to the locomotor domain. Taken together with evidence for parietal and cerebellar abnormalities in WS, these results also provide new evidence for the role of these circuits in the visual control of whole-body movement.