Features of developmental functions and autistic profiles in children with fragile X syndrome.
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BACKGROUND: In this study, we investigated the developmental functions and autistic profiles in children with Fragile X syndrome (FXS). In addition, we established the relationships between developmental and autistic profiles in these children. METHODS: The medical records of 12 children with FXS, aged 2 to 7 years, were collected. Fifteen children with autism, without FXS, who were age- and sex-matched were selected as the comparison group. All children underwent assessments of developmental functions according to the Chinese Child Development Inventory (CCDI), and autistic profiles according to the Childhood Autism Rating Scale (CARS). Differences in genders between the two groups were determined with the Fisher's exact test. Differences in developmental functions (CCDI) and autistic profiles (CARS) between the two groups were compared using Mann-Whitney U test and Bonferroni adjustment. The Spearman's rho correlation was used to determine the relationship of developmental functions and autistic profiles. RESULTS: All developmental functions in children with FXS were better than those with autism except for gross motor, fine motor and expressive language functions. Children with FXS had the worst expressive language function (56% Development Quotient, DQ) as compared with other developmental functions (> 70% DQ). The major difference between the children with FXS and those with autism was personal social function with a difference of 33% DQ. The average total CARS score were lower in children with FXS (average score, 28) than children with autism (average score, 34). Spearman's correlation demonstrated the CARS total score were negatively correlated with all developmental functions, except for gross motor function. CONCLUSIONS: Our findings suggest that the FXS children had multifaceted and disproportional development patterns in motor, speech and social domains when compared with the autism children without FXS. The developmental functions were inversely correlated with autistic profiles. Therefore, when applying comprehensive assessment, we were able to identify the special developmental features in children with FXS. (+info)
The Scottish low birthweight study: II. Language attainment, cognitive status, and behavioural problems.
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Of the 636 survivors of a total geographically based population born in Scotland in 1984, who weighed less than 1750 g at birth, 611 (96%) were assessed at 4.5 years to determine the prevalence of language, cognitive, and behavioural problems. Language development was significantly related to birth weight, gestational age, and social class for comprehension, less so for expressive language. Mean (SD) intelligence quotient (IQ) on the British ability scales was 92.9 (14.7). Within this population there were no significant differences between birthweight groups. Overall they performed poorly on visual recognition, verbal comprehension and number skills subscales--in the latter those with birth weights less than 1000 g were significantly worse than the heavier children. Only 5% had IQs less than 70, but a further 3% could not be tested because of other physical disability. Among those with normal IQs were groups of children who exhibited patterns of skill deficits in different subscales raising the possibility of specific learning difficulties. Poor attention span was reported in 47%, and parents said the study children had more behavioural problems than their siblings. (+info)
Grammatical Subjects in home sign: Abstract linguistic structure in adult primary gesture systems without linguistic input.
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Language ordinarily emerges in young children as a consequence of both linguistic experience (for example, exposure to a spoken or signed language) and innate abilities (for example, the ability to acquire certain types of language patterns). One way to discern which aspects of language acquisition are controlled by experience and which arise from innate factors is to remove or manipulate linguistic input. However, experimental manipulations that involve depriving a child of language input are impossible. The present work examines the communication systems resulting from natural situations of language deprivation and thus explores the inherent tendency of humans to build communication systems of particular kinds, without any conventional linguistic input. We examined the gesture systems that three isolated deaf Nicaraguans (ages 14-23 years) have developed for use with their hearing families. These deaf individuals have had no contact with any conventional language, spoken or signed. To communicate with their families, they have each developed a gestural communication system within the home called "home sign." Our analysis focused on whether these systems show evidence of the grammatical category of Subject. Subjects are widely considered to be universal to human languages. Using specially designed elicitation tasks, we show that home signers also demonstrate the universal characteristics of Subjects in their gesture productions, despite the fact that their communicative systems have developed without exposure to a conventional language. These findings indicate that abstract linguistic structure, particularly the grammatical category of Subject, can emerge in the gestural modality without linguistic input. (+info)
Broca's arrow: evolution, prediction, and language in the brain.
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Brodmann's areas 44 and 45 in the human brain, also known as Broca's area, have long been associated with language functions, especially in the left hemisphere. However, the precise role Broca's area plays in human language has not been established with certainty. Broca's area has homologs in the great apes and in area F5 in monkeys, which suggests that its original function was not linguistic at all. In fact, great ape and hominid brains show very similar left-over-right asymmetries in Broca's area homologs as well as in other areas, such as homologs to Wernicke's area, that are normally associated with language in modern humans. Moreover, the so-called mirror neurons are located in Broca's area in great apes and area F5 in monkeys, which seem to provide a representation of cause and effect in a primate's environment, particularly its social environment. Humans appear to have these mirror neurons in Broca's area as well. Similarly, genetic evidence related to the FOXP2 gene implicates Broca's area in linguistic function and dysfunction, but the gene itself is a highly conserved developmental gene in vertebrates and is shared with only two or three differences between humans and great apes, five between humans and mice, and eight between humans and songbirds. Taking neurons and portions of the brain as discrete computational segments in the sense of constituting specific Turing machines, this evidence points to a predictive motor and conceptual function for Broca's area in primates, especially for social concepts. In human language, this is consistent with evidence from typological and cognitive linguistics. (+info)
Some consequences of stimulus variability on speech processing by 2-month-old infants.
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The present study explores how stimulus variability in speech production influences the 2-month-old infant's perception and memory for speech sounds. Experiment 1 focuses on the consequences of talker variability for the infant's ability to detect differences between speech sounds. When tested with high-amplitude sucking (HAS) procedure, infants who listened to versions of a syllable, such as [symbol: see text], produced by 6 male and 6 female talkers, detected a change to another syllable, such as [symbol: see text], uttered by the same group of talkers. In fact, infants exposed to multiple talkers performed as well as other infants who heard utterances produced by only a single talker. Moreover, other results showed that infants discriminate the voices of the individual talkers, although discriminating one mixed group of talkers (3 males and 3 females) from another is too difficult for them. Experiment 2 explored the consequences of talker variability on infants' memory for speech sounds. The HAS procedure was modified by introducing a 2-min delay period between the familiarization and test phases of the experiment. Talker variability impeded infants' encoding of speech sounds. Infants who heard versions of the same syllable produced by 12 different talkers did not detect a change to a new syllable produced by the same talkers after the delay period. However, infants who heard the same syllable produced by a single talker were able to detect the phonetic change after the delay. Finally, although infants who heard productions from a single talker retained information about the phonetic structure of the syllable during the delay, they apparently did not retain information about the identity of the talker. Experiment 3 reduced the range of variability across talkers and investigated whether variability interferes with retention of all speech information. Although reducing the range of variability did not lead to retention of phonetic details, infants did recognize a change in the gender of the talkers' voices (from male to female or vice versa) after a 2-min delay. Two additional experiments explored the consequences of limiting the variability to a single talker. In Experiment 4, with an immediate testing procedure, infants exposed to 12 different tokens of one syllable produced by the same talker discriminated these from 12 tokens of another syllable.(ABSTRACT TRUNCATED AT 400 WORDS) (+info)
Language development in deaf children's interactions with deaf and hearing adults: a Dutch longitudinal study.
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The language development of two deaf girls and four deaf boys in Sign Language of the Netherlands (SLN) and spoken Dutch was investigated longitudinally. At the start, the mean age of the children was 3;5. All data were collected in video-recorded semistructured conversations between individual children and deaf and hearing adults. We investigated the lexical richness and syntactic complexity of the children's utterances in SLN and spoken Dutch, as well as language dominance and interactional participation. Richness and complexity increase over time, as well as children's participation. An important outcome is that syntactic complexity is higher in utterances with both sign and speech. SLN does not have higher outcomes on richness or complexity, but is dominant in terms of frequency of use. (+info)
A longitudinal functional magnetic resonance imaging study of language development in children 5 to 11 years old.
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OBJECTIVE: Language skills continue to develop rapidly in children during the school-age years, and the "snapshot" view of the neural substrates of language provided by current neuroimaging studies cannot capture the dynamic changes associated with brain development. The aim of this study was to conduct a 5-year longitudinal investigation of language development using functional magnetic resonance imaging in healthy children. METHODS: Thirty subjects enrolled at ages 5, 6, or 7 were examined annually for 5 years using a 3-Tesla magnetic resonance imaging scanner and a verb generation task. Data analysis was conducted based on a general linear model that was modified to investigate developmental changes whereas minimizing the potential for missing data. RESULTS: With increasing age, there is progressive participation in language processing by the inferior/middle frontal, middle temporal, and angular gyri of the left hemisphere and the lingual and inferior temporal gyri of the right hemisphere and regression of participation of the left posterior insula/extrastriate cortex, left superior frontal and right anterior cingulate gyri, and left thalamus. CONCLUSION: The age-related changes observed in this study provide evidence of increased neuroplasticity of language in this age group and may have implications for further investigations of normal and aberrant language development. (+info)
Errors in nonword repetition: bridging short- and long-term memory.
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According to the working memory model, the phonological loop is the component of working memory specialized in processing and manipulating limited amounts of speech-based information. The Children's Test of Nonword Repetition (CNRep) is a suitable measure of phonological short-term memory for English-speaking children, which was validated by the Brazilian Children's Test of Pseudoword Repetition (BCPR) as a Portuguese-language version. The objectives of the present study were: i) to investigate developmental aspects of the phonological memory processing by error analysis in the nonword repetition task, and ii) to examine phoneme (substitution, omission and addition) and order (migration) errors made in the BCPR by 180 normal Brazilian children of both sexes aged 4-10, from preschool to 4th grade. The dominant error was substitution [F(3,525) = 180.47; P < 0.0001]. The performance was age-related [F(4,175) = 14.53; P < 0.0001]. The length effect, i.e., more errors in long than in short items, was observed [F(3,519) = 108.36; P < 0.0001]. In 5-syllable pseudowords, errors occurred mainly in the middle of the stimuli, before the syllabic stress [F(4,16) = 6.03; P = 0.003]; substitutions appeared more at the end of the stimuli, after the stress [F(12,48) = 2.27; P = 0.02]. In conclusion, the BCPR error analysis supports the idea that phonological loop capacity is relatively constant during development, although school learning increases the efficiency of this system. Moreover, there are indications that long-term memory contributes to holding memory trace. The findings were discussed in terms of distinctiveness, clustering and redintegration hypotheses. (+info)