Cross-sectional and longitudinal assessment of cognitive development in Williams syndrome.

Williams syndrome (WS) is a rare genetic syndrome. As with all rare syndromes, obtaining adequately powered sample sizes is a challenge. Here we present legacy data from seven UK labs, enabling the characterisation of cross-sectional and longitudinal developmental trajectories of verbal and non-verbal development in the largest sample of individuals with WS to-date. In Study 1, we report cross-sectional data between N = 102 and N = 209 children and adults with WS on measures of verbal and non-verbal ability. In Study 2, we report longitudinal data from N = 17 to N = 54 children and adults with WS who had been tested on at least three timepoints on these measures. Data support the WS characteristic cognitive profile of stronger verbal than non-verbal ability, and shallow developmental progression for both domains. Both cross-sectional and longitudinal data demonstrate steeper rates of development in the child participants than the adolescent and adults in our sample. Cross-sectional data indicate steeper development in verbal than non-verbal ability, and that individual differences in the discrepancy between verbal and non-verbal ability are largely accounted for by level of intellectual functioning. A diverging developmental discrepancy between verbal and non-verbal ability, whilst marginal, is not mirrored statistically in the longitudinal data. Cross-sectional and longitudinal data are discussed with reference to validating cross-sectional developmental patterns using longitudinal data and the importance of individual differences in understanding developmental progression.

The role of context in verbal humor processing in autism.

Difficulties in processing humor have been associated with individuals with autism. The current study investigated whether humor comprehension and appreciation could be augmented in children with autism by providing contextual support suggesting that humor was to be expected. A verbally presented riddle task was used in which participants were assessed for their subjective ratings and comprehension of the materials. They were also filmed to record any smiling or laughing. Both riddles and control stimuli were presented with supporting verbal context and also without it. The results showed that (a) the greater subjective appreciation of riddles than of control stimuli was dependent on the provision of context for the participants with autism and that (b) context statistically equated these ratings of riddles between participants with autism and matched typically developing controls. However, context had no effect on comprehension or affective response. The results of the current study demonstrate that children with autism are, even in the most conservative interpretation, able to use verbal context to recognize verbal humor. This lays the foundation of possible interventions based on training sensitivity to context.

The development of children's comprehension and appreciation of riddles.

Humor appreciation and understanding is important for children's social relationships. The current study examined the associations among riddle comprehension, riddle appreciation, and smiling/laughter in children from a wide age range (4-11 years) as well as how cognitive processing style relates to riddle comprehension. Style was distinguished between local and global language processing at the sentence level. The results showed that only children age 8 years or older showed a reliable relationship between humor comprehension and smiling/laughter. These findings show that laughter should not be taken as an automatic indicator of explicit understanding. In addition, higher vocabulary ability was independently associated with better humor comprehension. This demonstrates a separable role of language proficiency in humor comprehension and suggests avenues for future research in atypical populations known to have difficulties in this area.

Déjà Vécu and Déjà Visité: Similarities and Differences: Further Results From an Online Questionnaire.

Over an 8-year period, an online questionnaire, devised as a pilot project, collected exploratory data in order to compare the particularities of déjà vécu (i.e., event related) experiences with those of déjà visité (i.e., location related). In a previous article it was shown that there are sufficient differences in the results for these two experiences to warrant considering them as being separate entities. Here, additional analyses have established a number of relationships that differ across the two phenomena. Their elucidation will require further investigations with improved research instruments and the studied population will have to be broader based in order to establish if the relationships determined here will be found to be true in the general population.

Improving working memory abilities in individuals with Down syndrome: a treatment case study.

Working memory (WM) skills of individuals with Down's syndrome (DS) tend to be very poor compared to typically developing children of similar mental age. In particular, research has found that in individuals with DS visuo-spatial WM is better preserved than verbal WM. This study investigated whether it is possible to train short-term memory (STM) and WM abilities in individuals with DS. The cases of two teenage children are reported: EH, 17 years and 3 months, and AS, 15 years and 11 months. A school-based treatment targeting visuo-spatial WM was given to EH and AS for six weeks. Both prior to and after the treatment, they completed a set of assessments to measure WM abilities and their performance was compared with younger typically developing non-verbal mental age controls. The results showed that the trained participants improved their performance in some of the trained and non-trained WM tasks proposed, especially with regard to the tasks assessing visuo-spatial WM abilities. These findings are discussed on the basis of their theoretical, educational, and clinical implications.

The development of route learning in Down syndrome, Williams syndrome and typical development: investigations with virtual environments.

The ability to navigate new environments has a significant impact on the daily life and independence of people with learning difficulties. The aims of this study were to investigate the development of route learning in Down syndrome (N = 50), Williams syndrome (N = 19), and typically developing children between 5 and 11 years old (N = 108); to investigate use of landmarks; and to relate cognitive functions to route-learning ability in these groups. Overall, measures of attention and long-term memory were strongly associated with route learning, even once non-verbal ability was controlled for. All of the groups, including 5- to 6-year-old TD children, demonstrated the ability to make use of all landmark types to aid route learning; those near junctions, those further from junctions, and also distant landmarks (e.g. church spire, radio mast). Individuals with WS performed better than a matched subset of TD children on more difficult routes; we suggest that this is supported by relatively strong visual feature recognition in the disorder. Participants with DS who had relatively high levels of non-verbal ability performed at a similar level to TD participants.

Route knowledge and configural knowledge in typical and atypical development: a comparison of sparse and rich environments.

BACKGROUND: Individuals with Down syndrome (DS) and individuals with Williams syndrome (WS) have poor navigation skills, which impact their potential to become independent. Two aspects of navigation were investigated in these groups, using virtual environments (VE): route knowledge (the ability to learn the way from A to B by following a fixed sequence of turns) and configural knowledge (knowledge of the spatial relationships between places within an environment). METHODS: Typically developing (TD) children aged 5 to 11 years (N = 93), individuals with DS (N = 29) and individuals with WS (N = 20) were presented with a sparse and a rich VE grid maze. Within each maze, participants were asked to learn a route from A to B and a route from A to C before being asked to find a novel shortcut from B to C. RESULTS: Performance was broadly similar across sparse and rich mazes. The majority of participants were able to learn novel routes, with poorest performance in the DS group, but the ability to find a shortcut, our measure of configural knowledge, was limited for all three groups. That is, 59 % TD participants successfully found a shortcut, compared to 10 % participants with DS and 35 % participants with WS. Differences in the underlying mechanisms associated with route knowledge and configural knowledge and in the developmental trajectories of performance across groups were observed. Only the TD participants walked a shorter distance in the last shortcut trial compared to the first, indicative of increased configural knowledge across trials. The DS group often used an alternative strategy to get from B to C, summing the two taught routes together. CONCLUSIONS: Our findings demonstrate impaired configural knowledge in DS and in WS, with the strongest deficit in DS. This suggests that these groups rely on a rigid route knowledge based method for navigating and as a result are likely to get lost easily. Route knowledge was also impaired in both DS and WS groups and was related to different underlying processes across all three groups. These are discussed with reference to limitations in attention and/or visuo-spatial processing in the atypical groups.

Poor phonemic discrimination does not underlie poor verbal short-term memory in Down syndrome.

Individuals with Down syndrome tend to have a marked impairment of verbal short-term memory. The chief aim of this study was to investigate whether phonemic discrimination contributes to this deficit. The secondary aim was to investigate whether phonological representations are degraded in verbal short-term memory in people with Down syndrome relative to control participants. To answer these questions, two tasks were used: a discrimination task, in which memory load was as low as possible, and a short-term recognition task that used the same stimulus items. Individuals with Down syndrome were found to perform significantly better than a nonverbal-matched typically developing group on the discrimination task, but they performed significantly more poorly than that group on the recognition task. The Down syndrome group was outperformed by an additional vocabulary-matched control group on the discrimination task but was outperformed to a markedly greater extent on the recognition task. Taken together, the results strongly indicate that phonemic discrimination ability is not central to the verbal short-term memory deficit associated with Down syndrome.

Short-term memory, executive control, and children's route learning.

The aim of this study was to investigate route-learning ability in 67 children aged 5 to 11years and to relate route-learning performance to the components of Baddeley's model of working memory. Children carried out tasks that included measures of verbal and visuospatial short-term memory and executive control and also measures of verbal and visuospatial long-term memory; the route-learning task was conducted using a maze in a virtual environment. In contrast to previous research, correlations were found between both visuospatial and verbal memory tasks-the Corsi task, short-term pattern span, digit span, and visuospatial long-term memory-and route-learning performance. However, further analyses indicated that these relationships were mediated by executive control demands that were common to the tasks, with long-term memory explaining additional unique variance in route learning.

Are imaging and lesioning convergent methods for assessing functional specialisation?: investigations using an artificial neural network.

This article presents an investigation of the relationship between lesioning and neuroimaging methods of assessing functional specialisation, using synthetic brain imaging (SBI) and lesioning of a connectionist network of past-tense formation. The model comprised two processing 'routes': one was a direct route between layers of input and output units, while the other, indirect, route featured an intermediate layer of processing units. Emergent specialisation within the network was assessed (1) by lesioning either the direct or indirect route and measuring past-tense performance for regular and irregular verbs, and (2) by measuring functional activation in each route when processing each verb type (SBI). SBI and lesioning approaches failed to converge when network activation was summed over each route in our SBI approach. Examination of individual network solutions suggested that the verb types might be using the indirect route differently in terms of the pattern of activation across the route, rather than in terms of gross activation. A subsequent SBI analysis compared patterns of activation in the indirect route and confirmed that these patterns were more similar between regular-type verbs than between regular and irregular verbs. As the spatial and temporal resolution of neuroimaging techniques improves, the results of this investigation suggest that the key to finding functional specialisation will be to distinguish local coding differences across behaviours that are the results of developmental processes. Other analyses suggest that lesioning data may be limited because, with increasing damage, they reveal the resting activations of a computational system rather than a computational specialisation per se.

Definitions versus categorization: assessing the development of lexico-semantic knowledge in Williams syndrome.

BACKGROUND: Williams syndrome (WS) is associated with relatively strong language abilities despite mild to moderate intellectual disability, particularly when language is indexed by vocabulary. AIMS: The aim of the study was twofold: (1) to investigate whether reported lexical anomalies in WS can be explained with reference to anomalous semantic development; and (2) to assess whether receptive vocabulary skills in WS, a relative strength, are underpinned by commensurate semantic knowledge. METHODS & PROCEDURES: The development of lexical-semantic knowledge was investigated in 45 typically developing individuals (chronological age range = 5-10 years, mental age range = 5-13 years) and 15 individuals with WS (chronological age range = 12-50 years, mental age range = 4-17 years) by means of (1) a categorization task and (2) a definitions task, which was expected to make additional metacognitive demands. OUTCOMES & RESULTS: At younger ages, the performance level of typically developing individuals and individuals with WS did not differ on the definitions task. However, the WS group's ability to define words fell away from the level predicted by the typically developing group at older ages, as more sophisticated definitions were expected. The results of the categorization task indicated that individuals with WS had less lexical-semantic knowledge than expected given their level of receptive vocabulary, although from this lower level the knowledge then developed at a similar rate to that found in typical development. CONCLUSIONS & IMPLICATIONS: It is concluded, first, that conventional vocabulary measures may overestimate lexical-semantic knowledge in WS; and, second, concerns about the metacognitive demands of the definitions task when used with atypical populations may be well founded.

The development of metaphorical language comprehension in typical development and in Williams syndrome.

The domain of figurative language comprehension was used to probe the developmental relation between language and cognition in typically developing individuals and individuals with Williams syndrome. Extending the work of Vosniadou and Ortony, the emergence of nonliteral similarity and category knowledge was investigated in 117 typically developing children between 4 and 12 years of age, 19 typically developing adults, 15 children with Williams syndrome between 5 and 12 years of age, and 8 adults with Williams syndrome. Participants were required to complete similarity and categorization statements by selecting one of two words (e.g., either "The sun is like --" or "The sun is the same kind of thing as --") with word pairs formed from items that were literally, perceptually, or functionally similar to the target word or else anomalous (e.g., moon, orange, oven, or chair, respectively). Results indicated that individuals with Williams syndrome may access different, less abstract knowledge in figurative language comparisons despite the relatively strong verbal abilities found in this disorder.