Investigating the extent of neuroplasticity: Writing in children with perinatal stroke.

The developing brain is remarkably plastic, as evidenced by language studies of children with perinatal stroke (PS). Despite initial delays and in contrast to adults with comparable lesions, children with PS perform comparably to their age-matched peers in free conversation by school age. Recent studies of spoken language in older children with PS have indicated limits to neural plasticity. Writing, a cognitively demanding and language dependent domain, is understudied in children with PS. Investigating writing development will provide another perspective on the continuing linguistic development in this population. Written language performance in 43 children with PS and 60 of their typically-developing (TD) peers was evaluated to further investigate the breadth and limits to neural plasticity. Two tasks of varying difficulty were administered: a picture description, which provided a referent to facilitate writing for the children, and a more challenging autobiographical narrative. Texts were analyzed across three broad writing dimensions - productivity, complexity, and linguistic accuracy. Group differences were primarily found on accuracy indices. Morphological accuracy was most impacted by early brain injury and older children with PS did not have higher morphological accuracy than their younger counterparts, suggesting limited development with age. There were no differences in performance based on hemisphere of lesion. In addition to enhancing our understanding of long-term language outcomes in children with PS, the results further illuminate the extent and limitations of early neural plasticity for language.

Language and affective facial expression in children with perinatal stroke.

Children with perinatal stroke (PS) provide a unique opportunity to understand developing brain-behavior relations. Previous research has noted distinctive differences in behavioral sequelae between children with PS and adults with acquired stroke: children fare better, presumably due to the plasticity of the developing brain for adaptive reorganization. Whereas we are beginning to understand language development, we know little about another communicative domain, emotional expression. The current study investigates the use and integration of language and facial expression during an interview. As anticipated, the language performance of the five and six year old PS group is comparable to their typically developing (TD) peers, however, their affective profiles are distinctive: those with right hemisphere injury are less expressive with respect to affective language and affective facial expression than either those with left hemisphere injury or TD group. The two distinctive profiles for language and emotional expression in these children suggest gradients of neuroplasticity in the developing brain.

Orthographic and semantic processing in young readers.

This investigation examined orthographic and semantic processing during reading acquisition. Children in first through fourth grade were presented with a target word and two response alternatives, and were asked to identify the semantic match. Words were presented in four conditions: an exact match and unrelated foil (STONE - STONE - EARS), an exact match and an orthographic neighbor foil (STONE - STONE - STOVE), a synonym match and an unrelated foil (STONE - ROCK - EARS), and a synonym match and an orthographic neighbor foil (STONE - ROCK - STOVE). Accuracy and reaction time results suggest that orthographic and semantic processing follow a two-step acquisition pattern. First, the orthographic component of reading develops quickly, however, forming strong conceptual links from orthographic to semantic representations follows a protracted trajectory, which matures between the third and fourth grade. These results are consistent with research that suggests younger children rely on more concrete, perceptual systems and then transition to more flexible, abstract cognition.

Gray matter structure and morphosyntax within a spoken narrative in typically developing children and children with high functioning autism.

This study examined the relationship between magnetic resonance imaging (MRI)-based measures of gray matter structure and morphosyntax production in a spoken narrative in 17 typical children (TD) and 11 children with high functioning autism (HFA) between 6 and 13 years of age. In the TD group, cortical structure was related to narrative performance in the left inferior frontal gyrus (Broca's area), the right middle frontal sulcus, and the right inferior temporal sulcus. No associations were found in children with HFA. These findings suggest a systematic coupling between brain structure and spontaneous language in TD children and a disruption of these relationships in children with HFA.

White matter microstructure correlates of narrative production in typically developing children and children with high functioning autism.

This study investigated the relationship between white matter microstructure and the development of morphosyntax in a spoken narrative in typically developing children (TD) and in children with high functioning autism (HFA). Autism is characterized by language and communication impairments, yet the relationship between morphosyntactic development in spontaneous discourse contexts and neural development is not well understood in either this population or typical development. Diffusion tensor imaging (DTI) was used to assess multiple parameters of diffusivity as indicators of white matter tract integrity in language-related tracts in children between 6 and 13 years of age. Children were asked to spontaneously tell a story about at time when someone made them sad, mad, or angry. The story was evaluated for morphological accuracy and syntactic complexity. Analysis of the relationship between white matter microstructure and language performance in TD children showed that diffusivity correlated with morphosyntax production in the superior longitudinal fasciculus (SLF), a fiber tract traditionally associated with language. At the anatomical level, the HFA group showed abnormal diffusivity in the right inferior longitudinal fasciculus (ILF) relative to the TD group. Within the HFA group, children with greater white matter integrity in the right ILF displayed greater morphological accuracy during their spoken narrative. Overall, the current study shows an association between white matter structure in a traditional language pathway and narrative performance in TD children. In the autism group, associations were only found in the ILF, suggesting that during real world language use, children with HFA rely less on typical pathways and more on alternative ventral pathways that possibly mediate visual elements of language.

Lexical spelling in children and adolescents with specific language impairment: variations with the writing situation.

The goal of this study was to compare the lexical spelling performance of children and adolescents with specific language impairment (SLI) in two contrasting writing situations: a dictation of isolated words (a classic evaluative situation) and a narrative of a personal event (a communicative situation). Twenty-four children with SLI and 48 typically developing children participated in the study, split into two age groups: 7-11 and 12-18 years of age. Although participants with SLI made more spelling errors per word than typically developing participants of the same chronological age, there was a smaller difference between the two groups in the narratives than in the dictations. Two of the findings are particularly noteworthy: (1) Between 12 and 18 years of age, in communicative narration, the number of spelling errors of the SLI group was not different from that of the typically developing group. (2) In communicative narration, the participants with SLI did not make specific spelling errors (phonologically unacceptable), contrary to what was shown in the dictation. From an educational perspective or that of a remediation program, it must be stressed that the communicative narration provides children-and especially adolescents-with SLI an opportunity to demonstrate their improved lexical spelling abilities. Furthermore, the results encourage long-term lexical spelling education, as adolescents with SLI continue to show improvement between 12 and 18 years of age.

Later language development in narratives in children with perinatal stroke.

Studies of young children with unilateral perinatal stroke (PS) have confirmed the plasticity of the developing brain for acquiring language. While recent studies of typically developing children have demonstrated the significant development of language well into adolescence, we know little regarding the course of language development in the PS group as they mature. Will children with PS continue to show the same remarkable plasticity that they exhibited at younger ages? In the present paper we investigate later language and discourse in children with perinatal stroke (ages 7-16) using spoken personal narrative as the discourse context. In contrast to the findings of the discourse studies of younger children with PS, children with left hemisphere lesions made more morphological errors, used less complex syntax and fewer syntactic types than controls; they also produced more impoverished story settings. In contrast, those with right hemisphere lesions performed comparably to controls, except in their impoverished use of complex syntax. The findings provide insight into the nature of later spoken language development in these children, revealing both the nature and extent of neuroplasticity for language as well as potential regional biases.

Affiliative behavior in Williams syndrome: social perception and real-life social behavior.

A frequently noted but largely anecdotal behavioral observation in Williams syndrome (WS) is an increased tendency to approach strangers, yet the basis for this behavior remains unknown. We examined the relationship between affect identification ability and affiliative behavior in participants with WS relative to a neurotypical comparison group. We quantified social behavior from self-judgments of approachability for faces, and from parent/other evaluations of real life. Relative to typical individuals, participants with WS were perceived as more sociable by others, exhibited perceptual deficits in affect identification, and judged faces of strangers as more approachable. In WS, high self-rated willingness to approach strangers was correlated with poor affect identification ability, suggesting that these two findings may be causally related. We suggest that the real-life hypersociability in WS may arise at least in part from abnormal perceptual processing of other people's faces, rather than from an overall bias at the level of behavior. While this did not achieve statistical significance, it provides preliminary evidence to suggest that impaired social-perceptual ability may play a role in increased approachability in WS.

Recognition of emotional and nonemotional facial expressions: a comparison between Williams syndrome and autism.

The aim of our study was to compare two neurodevelopmental disorders (Williams syndrome and autism) in terms of the ability to recognize emotional and nonemotional facial expressions. The comparison of these two disorders is particularly relevant to the investigation of face processing and should contribute to a better understanding of social behaviour and social cognition. Twelve participants with WS (from 6;1 to 15 years) and twelve participants with autism (from 4;9 to 8 years) were matched on verbal mental age. Their performances were compared with those of twelve typically developing controls matched on verbal mental age (from 3;1 to 9;2). A set of five tasks assessing different dimensions of emotional and nonemotional facial recognition were administered. Results indicated that recognition of emotional facial expressions is more impaired in Williams syndrome than in autism. Our study comparing Williams syndrome and autism over a small age range highlighted two distinct profiles which call into question the relationships between social behaviour/cognition and emotion perception.

Association between cerebral shape and social use of language in Williams syndrome.

Williams syndrome (WS) is a neurogenetic disorder resulting from a hemizygous microdeletion at band 7q11.23. It is characterized by aberrant development of the brain and a unique profile of cognitive and behavioral features. We sought to identify the neuroanatomical abnormalities that are most strongly associated with WS employing signal detection methodology. Once identified with a Quality Receiver Operating Characteristic Curve (QROC), we hypothesized those brain regions distinguishing subjects with WS from controls would be linked to the social phenotype of individuals with this disorder. Thirty-nine adolescents and young adults with WS and 40 typically developing controls matched for age and gender were studied. The QROC identified a combination of an enlarged ventral anterior prefrontal cortex and large bending angle of the corpus callosum to distinguish between WS and controls with a sensitivity of 85.4% and specificity of 75.0%. Within the WS group, bending angle significantly correlated with ventral anterior prefrontal cortex size but not with other morphometric brain measures. Ventral anterior prefrontal size in subjects with WS was positively associated with the use of social engagement devices in a narrative task assessing the use of social and affective language. Our findings suggest that aberrant morphology of the ventral anterior prefrontal cortex is a pivotal contributing factor to the abnormal size and shape of the cerebral cortex and to the social-affective language use typical of individuals with WS.

Defining the social phenotype in Williams syndrome: a model for linking gene, the brain, and behavior.

Research into phenotype-genotype correlations in neurodevelopmental disorders has greatly elucidated the contribution of genetic and neurobiological factors to variations in typical and atypical development. Etiologically relatively homogeneous disorders, such as Williams syndrome (WS), provide unique opportunities for elucidating gene-brain-behavior relationships. WS is a neurogenetic disorder caused by a hemizygous deletion of approximately 25 genes on chromosome 7q11.23. This results in a cascade of physical, cognitive-behavioral, affective, and neurobiological aberrations. WS is associated with a markedly uneven neurocognitive profile, and the mature state cognitive profile of WS is relatively well developed. Although anecdotally, individuals with WS have been frequently described as unusually friendly and sociable, personality remains a considerably less well studied area. This paper investigates genetic influences, cognitive-behavioral characteristics, aberrations in brain structure and function, and environmental and biological variables that influence the social outcomes of individuals with WS. We bring together a series of findings across multiple levels of scientific enquiry to examine the social phenotype in WS, reflecting the journey from gene to the brain to behavior. Understanding the complex multilevel scientific perspective in WS has implications for understanding typical social development by identifying important developmental events and markers, as well as helping to define the boundaries of psychopathology.

Early environmental factors, ethnicity, and adult cognitive test performance.

This study was conducted to better understand cross-cultural variation in neuropsychological test performance by exploring the relationship between early environmental factors and adult neuropsychological functioning in African Americans (AA) and Caucasians (CA). Cognitive testing data and detailed retrospective early environmental histories were obtained from 100 neurologically healthy adults (75 AA, 25 CA). Results indicate that: (a) consistent with previous research, the two ethnic groups differed significantly on their cognitive test performance; (b) early environmental factors were significantly related to performance on cognitive tests; (c) the two ethnic groups demonstrated slight, but significant, differences in their early environmental histories; but (d) covarying early environmental factors did not substantially reduce the group performance in cognitive test performance. The failure of reported environmental factors to account for more of the ethnic disparity in test performance may have resulted from the inherent weakness of the retrospective assessment method (i.e., lack of precision or objectivity in participants' recollections of their early environments). These results highlight the remaining need for ethnicity specific normative data until cross-cultural variation in neuropsychological test performance is better understood.

Cognitive development following early brain injury: evidence for neural adaptation.

Over the past few decades a large body of work from developmental neurobiology has shown that mammalian brain development is the product of dynamic and adaptive processes operating within highly constrained, but continually changing, biological and environmental contexts. The recent study of children with prenatal focal brain injury supports this dynamic view of development for humans. Children's injuries often affect substantial portions of one cerebral hemisphere, resulting in damage that would compromise cognitive ability in adults. However, longitudinal behavioral studies of this population have revealed only mild deficits. It is suggested here that children's capacity for adaptation reflects normal developmental processes operating against a backdrop of serious neural perturbation. Data from three behavioral domains--linguistics, spatial cognition and affective development--illustrate this complex profile of change.

A crosslinguistic study of the relationship between grammar and lexical development.

The relationship between grammatical and lexical development was compared in 233 English and 233 Italian children aged between 1;6 and 2;6, matched for age, gender, and vocabulary size on the MacArthur Communicative Development Inventories (CDI). Four different measures of Mean Length of Utterance were applied to the three longest utterances reported by parents, and to corrected/expanded versions representing the 'target' for each utterance. Italians had longer MLUs on most measures, but the ratio of actual to target MLUs did not differ between languages. Age and vocabulary both contributed significant variance to MLU, but the contribution of vocabulary was much larger, suggesting that vocabulary size may provide a better basis for crosslinguistic comparisons of grammatical development. The relationship between MLU and vocabulary size was non-linear in English but linear in Italian, suggesting that grammar 'gets off the ground' earlier in a richly inflected language. A possible mechanism to account for this difference is discussed.

Mechanisms of verbal memory impairment in four neurodevelopmental disorders.

Profiles of verbal learning and memory performance were compared for typically developing children and for four developmental disorders characterized by different patterns of language functioning: specific language impairment, early focal brain damage, Williams Syndrome, and Down Syndrome. A list-learning task was used that allowed a detailed examination of the process of verbal learning, recall, and recognition (California Verbal Learning Test--Children's Version). Distinct patterns of performance characterized the four disorders. These patterns were consistent with the language deficits typically seen in the disorders, with the exception of a dissociation seen in Williams Syndrome.

The development of morphosyntactic ability in atypical populations: The acquisition of tag questions in children with early focal lesions and children with specific-language impairment.

We examined the development of some features of morphosyntactic ability, specifically the acquisition of auxiliaries and use of agreement marking, along with sentence processing capacity. We used a conceptually simple task called the Tags Question Task, which is a method for evaluating a number of language processes in the production of a commonly used, familiar linguistic device. We compared the performance of children with early focal lesions (N=21), children with specific-language impairment (N=24), and typically developing children (N=24) matched in age and nonverbal ability; additional analyses involved comparisons of children matched on performance level. The data converge to support a "delayed" development of language behavior in our clinical groups, as overall patterns of performance and age-related changes on individual tag features and tag questions were strikingly similar in all three groups across a number of methods of comparison. Implications for theories of the development of brain-language relationships as they pertain to early focal brain damage, specific-language impairment, and the language acquisition process in typically developing children are discussed.

Language development in children at risk for language impairment: cross-population comparisons.

At 3 years of age the spontaneous language of 17 typically developing children was compared to two groups of toddlers who were at risk for language delay for very different reasons. One at-risk group, late talkers, appeared normal in all respects except for their delayed language. These 20 children scored at or below the fifteenth percentile for expressive vocabulary on the MacArthur Communicative Development Inventory (Fenson et al., 1993) when originally identified at 20-27 months of age and within the normal range on the Bayley Scales of Infant Development (Bayley, 1969). The other group, 21 children with unilateral focal brain injury, suffered localized damage to their brain prenatally, perinatally, or within the first 6 months of life. Results indicated that both of the at-risk groups were still significantly lower in vocabulary diversity and grammar at 3 years of age. There was also significantly greater variability in the at-risk groups than in the control groups, and in the children with focal brain injury than in the late talkers in both areas. The importance of language comprehension to development in this period was supported by two findings. First, children with focal brain injury had significantly lower scores than late talkers on the Index of Productive Syntax, a test of emerging grammar, and had been lower in comprehension on a standardized test of language comprehension a year earlier. Second, late talkers with delay in comprehension as well as production had significantly lower scores on IPSyn than those with normal comprehension, suggesting that they are at greater risk for continued delay. Qualitative analyses indicated that the at-risk groups produced the same kinds of errors, but that late talkers produced a substantially greater proportion of errors in obligatory contexts than did children with focal brain injury.

"Frog, where are you?" Narratives in children with specific language impairment, early focal brain injury, and Williams syndrome.

In this cross-population study, we use narratives as a context to investigate language development in children from 4 to 12 years of age from three experimental groups: children with early unilateral focal brain damage (FL; N=52); children with specific language impairment (SLI; N=44); children with Williams syndrome (WMS; N=36), and typically developing controls. We compare the developmental trajectories of these groups in the following domains: morphological errors, use of complex syntax, complexity of narrative structure, and types and frequency of evaluative devices. For the children with early unilateral brain damage, there is initial delay. However, by age 10, they are generally within the normal range of performance for all narrative measures. Interestingly, there are few, if any, side specific differences. Children with SLI, who have no frank neurological damage and show no cognitive impairment demonstrate significantly more delay on all morphosyntactic measures than the FL group. Quantitatively, on morphosyntactic measures, the SLI group clusters with those children with WMS who are moderately retarded. Together these data help us to understand the extent and nature of brain plasticity for language development and those aspects of language and discourse that are dissociable.

Cognitive efficiency on a match to sample task decreases at the onset of puberty in children.

Electrocortical evidence indicates that a wave of synaptic proliferation occurs in the frontal lobes around the age of puberty onset. To study its potential influence on cognition, we examined 246 children (10-17 years) and 49 young adults (18-22 years) using a match-to-sample type of task to measure reaction times to assess emotionally related information. Based upon the instruction set, subjects made a yes/no decision about the emotion expressed in a face, a word, or a face/word combination presented tachistoscopically for 100 ms. The faces were images of a single individual with a happy, angry, sad or neutral expression. The words were 'happy,' 'angry,' 'sad,' or 'neutral,' In the combined stimulus condition, subjects were asked to decide if the face and word matched for the same emotion. Results showed that compared to the previous year, reaction times were significantly slower for making a correct decision at 11 and 12 years of age in girls and boys, the approximate ages of puberty onset. The peripubertal rise in reaction time declined slowly over the following 2-3 years and stabilized by 15 years of age. Analyses of the performance of 15-17 year olds revealed significantly longer reaction times in females to process both faces and words compared to males. However, this sex difference in late puberty appeared to be transient since it was not present in 18-22 year olds. Given the match-to-sample nature of the task employed, the puberty related increases in reaction time may reflect a relative inefficiency in frontal circuitry prior to the pruning of excess synaptic contacts.