Naming skills of children born preterm in comparison with their term peers at the ages of 9 and 16 years

Longstanding Auditory Sensory and Semantic Differences in Preterm Born Children

More than 10% of births are preterm, and the long-term consequences on sensory and semantic processing of non-linguistic information remain poorly understood. 17 very preterm-born children (born at < 33 weeks gestational age) and 15 full-term controls were tested at 10 years old with an auditory object recognition task, while 64-channel auditory evoked potentials (AEPs) were recorded. Sounds consisted of living (animal and human vocalizations) and manmade objects (e.g. household objects, instruments, and tools). Despite similar recognition behavior, AEPs strikingly differed between full-term and preterm children. Starting at 50ms post-stimulus onset, AEPs from preterm children differed topographically from their full-term counterparts. Over the 108-224ms post-stimulus period, full-term children showed stronger AEPs in response to living objects, whereas preterm born children showed the reverse pattern; i.e. stronger AEPs in response to manmade objects. Differential brain activity between semantic categories could reliably classify children according to their preterm status. Moreover, this opposing pattern of differential responses to semantic categories of sounds was also observed in source estimations within a network of occipital, temporal and frontal regions. This study highlights how early life experience in terms of preterm birth shapes sensory and object processing later on in life.

Interaction of Impulsivity, Attention, and Intelligence in Early Adolescents Born Preterm without Sequelae

There is insufficient evidence on the intellectual and attentional profile of adolescents born prematurely. Aim: to identify maladjustment in intellectual and attention skills at the beginning of secondary school. Method: 69 premature 12-year-old adolescents were evaluated with the WISC, d2 Test of Attention, and Test of Perception of Differences-Revised (CARAS-R). Results: adolescents present intellectual and attention abilities in the normal range. However, all premature adolescents show difficulties in impulse control and female adolescents are better in processing speed. Depending on the category of prematurity, differences in attention skills are evident. Conclusion: adolescents born prematurely without associated sequelae have significantly lower performance in the same areas than the normative group. This could affect the cognitive control of their behavior and academic performance in the medium and long term. Great prematurity could interfere with attention skills and self-control even at the age of 12, especially in males.

Children born before 32 weeks of gestation displayed impaired reading fluency, comprehension and spelling skills at 9 years of age

AIM

Our aim was to study whether prematurity, associated with prenatal and neonatal risk factors, affects specific literacy skills among school children born at a very low gestational age (VLGA) of <32 weeks.

METHODS

The study group comprised 76 prospectively followed VLGA children born between November 1998 and November 2002 at Oulu University Hospital, Finland, and 51 term controls. The median gestational age of the VLGA children was 29.0 (24.1-31.9) weeks. All children were examined at a median age of 8.9 (8.0-9.9) years in Oulu between November 2007 and November 2011. Reading fluency, comprehension and spelling skills were evaluated using standardised tests for Finnish-speaking children.

RESULTS

Very low gestational age children had significantly poorer test results in reading comprehension (median 6.9 vs 8.3, P = .014) and spelling (median 35.7 vs 38.0, P = .013) than term children. Furthermore, VLGA children more often performed below the 10th percentile normal values in spelling (P = .012) compared with term controls. Foetal growth restriction was associated with lower scoring in reading fluency (P = .023) and spelling (P = .004) among VLGA children.

CONCLUSION

Very low gestational age school children performed poorer in reading comprehension and spelling than term children. In addition, poor foetal growth in VLGA children was associated with literacy problems.

Uneven Linguistic Outcome in Extremely Preterm Children

One primary problem in extremely preterm children is the occurrence of atypical language development. The aim of this study was to explore the components of language (articulatory phonetics, lexicon and syntax) in comprehension and production in extremely preterm children between the 4th and 5th year of age. The language section of the Preschool Neuropsychological Test was administered to 20 extremely preterm monolingual Italian children (GA < 28 weeks) and to a control sample of 40 full term children (GA > 37 weeks), matched for age and non-verbal IQ. Language comprehension was fully efficient in all of the components that we assessed. In the tasks of language production the clinical sample fared much worse than their age and IQ matched controls and the differences were highly significant (p < .001). Language acquisition in extremely preterm children may follow uneven developmental trajectories: language comprehension can be spared in the face of a selective impairment of language production at the level of articulatory phonetics and syntax.

Evolution of Sex Differences in Trait- and Age-Specific Vulnerabilities

Traits that facilitate competition for reproductive resources or that influence mate choice generally have a heightened sensitivity to stressors. They have evolved to signal resilience to infectious disease and nutritional and social stressors, and they are compromised by exposure to man-made toxins. Although these traits can differ from one species or sex to the next, an understanding of the dynamics of competition and choice can in theory be used to generate a priori predictions about sex-, age-, and trait-specific vulnerabilities for any sexually reproducing species. I provide a review of these dynamics and illustrate associated vulnerabilities in nonhuman species. The age- and sex-specific vulnerability of such traits is then illustrated for stressor-related disruptions of boys’ and girls’ physical growth and play behavior, as well as for aspects of boys’ and girls’ and men’s and women’s personality, language, and spatial abilities. There is much that remains to be determined, but enough is now known to reframe trait sensitivity in ways that will allow scientists and practitioners to better identify and understand vulnerable human traits, and eventually ameliorate or prevent their expression.

Word recognition and phonological representation in very low birth weight preterms

BACKGROUND

Several studies have shown impaired neurocognitive development in infants born very preterm. Language is one of the areas that may be affected. Early lexical development measurements have revealed possible delays associated with low gestational age, but no studies have analyzed lexical processing using real-time measures in this at-risk population.

AIMS

To explore the effects of preterm birth on the robustness of phonological representations and lexical processing speed.

SUBJECTS AND METHODS

Eighteen two-year-old VLBW healthy preterms (≤32weeks of gestation; ≤1500g) and a matched group of at term infants, equivalent in age, gender, SES, linguistic environment and expressive lexicon were compared in a 'looking-while-listening' task, using correctly pronounced and mispronounced known words involving a vowel change. Percentage of target fixation, longest look duration, shift rate and orientation latency measures were used to analyze possible between-group differences in phonological representation and familiar word recognition processes.

RESULTS

Based on the percentage of fixation time measure both groups succeeded at word recognition and responded similarly to mispronunciations. However, preterms significantly differed from full-terms in processing speed measures, showing longer look duration, lower shift rate and slower orientation latencies to target from distracter.

CONCLUSIONS

Preterm birth negatively affects lexical processing speed. Birth weight and gestational age are two critical variables in these results. Slower language processing in preterms can compromise the acquisition of more complex lexical and grammatical representations later in development and may underlie poor language outcomes frequently observed in children born very prematurely.

Outcome of extremely low birth weight infants: what's new in the third millennium? Neuropsychological profiles at four years

BACKGROUND

Extremely low birth weight (ELBW) infants, even those not presenting severe neuromotor sequelae, continue to be at risk of developing multiple, complex disorders involving the cognitive, emotional and behavioural domains. Follow-up protocols are able, in the short term, to identify subjects at risk of developing major sequelae, however they fail to identify all children at risk of developing disorders.

AIMS

To investigate the cognitive, neuropsychological and behavioural outcomes of a sample of ELBW children at the age of four years in order to identify characteristic profiles.

STUDY DESIGN

Longitudinal study.

SUBJECTS

16 healthy ELBW children born in 2005 and followed up until the age of four.

OUTCOME MEASURE

Performances on standardised tests evaluating intelligence, memory, cognitive visual functions, attention, and executive functions.

RESULTS

General intelligence was within normal range. Cognitive profile showed mild or moderate deficits with different levels of involvement in many of the examined functions, in particular executive functions, attention and naming.

CONCLUSION

There emerged a wide-ranging spectrum of weaknesses and deficits involving all the functions examined, which together give rise to a dysexecutive syndrome. Analysis of cognitive profiles showed that the sample could be divided into two subgroups of subjects that differ in the quality of their global cognitive and behavioural functioning. Our results confirm the need to continue follow up of ELBW children until school age, as this will allow early detection of at-risk children and the planning of timely preventive interventions.

Longitudinal assessment of intellectual abilities of children with Williams syndrome: multilevel modeling of performance on the Kaufman Brief Intelligence Test-Second Edition

Multilevel modeling was used to address the longitudinal stability of standard scores (SSs) measuring intellectual ability for children with Williams syndrome (WS). Participants were 40 children with genetically confirmed WS who completed the Kaufman Brief Intelligence Test-Second Edition (KBIT-2; A. S. Kaufman & N. L. Kaufman, 2004 ) 4-7 times over a mean of 5.06 years. Mean age at first assessment was 7.44 years (range  =  4.00-13.97 years). On average, KBIT-2 Composite IQ, Verbal SS, and Nonverbal SS were stable from 4 to 17 years, although there were significant individual differences in intercept (Composite IQ, Verbal SS, Nonverbal SS) and slope (Composite IQ, Nonverbal SS). Maternal education was significantly related to Verbal SS intercept. No significant sex differences were found. Implications for studies of genotype/phenotype correlations in WS are discussed.

Inattentive behaviour is associated with poor working memory and slow processing speed in very pre-term children in middle childhood

BACKGROUND. Problem behaviour is common following pre-term birth, but the underlying nature of these difficulties is not well known. AIMS. We sought to establish the mechanisms underpinning behavioural difficulties in very pre-term (VPT) children in middle childhood by comparing their performance to that of term born peers on tasks of working memory, inhibition, and processing speed, and relating these to parent and teacher assessments of their behaviour. Particular focus was given to inattention and overactive/impulsive behaviour, as these behaviours have been associated with different neuropsychological problems in term children. SAMPLES. A group of VPT children (gestational age < 31 weeks, N= 56) aged 9-10 years and term controls (N= 22) participated in the study. METHOD. Children were assessed with measures of working memory, inhibition, and processing speed. Parents and teachers reported behavioural problems using the Strengths and Difficulties Questionnaire and two additional scales measuring overactive/impulsive behaviour and inattention. RESULTS. Results revealed increased rates of problem behaviour in VPT compared to term children for parent-rated total difficulties, hyperactivity, emotional problems, peer problems, prosocial behaviour, overactive/impulsive behaviour, and parent- and teacher-rated inattention. Processing speed and working memory, but not inhibition, were significantly related to inattentive and overactive/impulsive behaviour. CONCLUSIONS. The increased rates of inattention and overactive/impulsive behaviour in VPT children may be explained by impairment in processing speed and working memory. Expected links between overactive/impulsive behaviour and inhibitory control were not identified, suggesting the nature of such difficulties may be different in VPT compared to term children.

Specific language and reading skills in school-aged children and adolescents are associated with prematurity after controlling for IQ

Although studies of long-term outcomes of children born preterm consistently show low intelligence quotient (IQ) and visual-motor impairment, studies of their performance in language and reading have found inconsistent results. In this study, we examined which specific language and reading skills were associated with prematurity independent of the effects of gender, socioeconomic status (SES), and IQ. Participants from two study sites (N=100) included 9-16-year old children born before 36 weeks gestation and weighing less than 2500 grams (preterm group, n=65) compared to children born at 37 weeks gestation or more (full-term group, n=35). Children born preterm had significantly lower scores than full-term controls on Performance IQ, Verbal IQ, receptive and expressive language skills, syntactic comprehension, linguistic processing speed, verbal memory, decoding, and reading comprehension but not on receptive vocabulary. Using MANCOVA, we found that SES, IQ, and prematurity all contributed to the variance in scores on a set of six non-overlapping measures of language and reading. Simple regression analyses found that after controlling for SES and Performance IQ, the degree of prematurity as measured by gestational age group was a significant predictor of linguistic processing speed, β=-.27, p<.05, R(2)=.07, verbal memory, β=.31, p<.05, R(2)=.09, and reading comprehension, β=.28, p<.05, R(2)=.08, but not of receptive vocabulary, syntactic comprehension, or decoding. The language and reading domains where prematurity had a direct effect can be classified as fluid as opposed to crystallized functions and should be monitored in school-aged children and adolescents born preterm.

Precursors to language in preterm infants: speech perception abilities in the first year of life

Language development in infants born very preterm is often compromised. Poor language skills have been described in preschoolers and differences between preterms and full terms, relative to early vocabulary size and morphosyntactical complexity, have also been identified. However, very few data are available concerning early speech perception abilities and their predictive value for later language outcomes. An overview of the results obtained in a prospective study exploring the link between early speech perception abilities and lexical development in the second year of life in a population of very preterm infants (≤32 gestation weeks) is presented. Specifically, behavioral measures relative to (a) native-language recognition and discrimination from a rhythmically distant and a rhythmically close nonfamiliar languages, and (b) monosyllabic word-form segmentation, were obtained and compared to data from full-term infants. Expressive vocabulary at two test ages (12 and 18 months, corrected age for gestation) was measured using the MacArthur Communicative Development Inventory. Behavioral results indicated that differences between preterm and control groups were present, but only evident when task demands were high in terms of language processing, selective attention to relevant information and memory load. When responses could be based on acquired knowledge from accumulated linguistic experience, between-group differences were no longer observed. Critically, while preterm infants responded satisfactorily to the native-language recognition and discrimination tasks, they clearly differed from full-term infants in the more challenging activity of extracting and retaining word-form units from fluent speech, a fundamental ability for starting to building a lexicon. Correlations between results from the language discrimination tasks and expressive vocabulary measures could not be systematically established. However, attention time to novel words in the word segmentation task yielded a significant correlation with vocabulary at both test ages. The predictive value of the behavioral measures in this research for an early identification of language delays in the preterm population was, thus, limited. However, early evidence of preterms' difficulties in speech and language processing tasks involving complex materials reveals a weakness in their initial approach to the language acquisition process that may constrain their future language skills well beyond the prelexical stage.

Long-term effects of preterm birth on language and literacy at eight years

The aims of this study were to investigate whether specific linguistic difficulties in preterm children persist at eight years and to examine the interrelationships between language and literacy in this population, compared with a control group of full-term children. Sixty-eight monolingual Italian preterms and 26 chronologically matched controls were recruited. Language (grammar comprehension, lexical production and phonological awareness), literacy (reading comprehension, reading and writing) and general cognitive development were investigated. Results showed no general delay in preterms, but slight difficulties in specific linguistic abilities (grammar, lexicon, phoneme synthesis and deletion of the first syllable), more difficulties in literacy (speed in reading and accuracy in writing) and certain correlations among competencies turning out to be different from the control group. In conclusion, our study established that a partially atypical trajectory emerged in preterms, showing specific long-term effects of preterm birth on language and literacy development.

Reconsidering the impact of preterm birth on language outcome

BACKGROUND

Since preterm birth is associated with a constellation of pre-, peri- and post-natal risk factors, we hypothesised that prematurity may continue to impact the development of linguistic abilities even up to the end of the preschool years and beyond, giving rise to an atypical developmental trajectory. The study tested this hypothesis at six years of age, investigating whether language is affected by preterm birth and how different linguistic abilities are interrelated.

METHOD

Seventy monolingual Italian preterms and 34 age-matched controls were recruited. Linguistic abilities (vocabulary, grammar, and phonological awareness) as well as general cognitive developmental levels were measured.

RESULTS

No general cognitive delay emerged, but less developed abilities in vocabulary, grammar, and phonological awareness were found in preterms compared to fullterms. Moreover, the relations among the different linguistic competences differed across groups.

CONCLUSIONS

Our study shows that even without brain damage, preterm birth continues to affect linguistic development up to the end of the preschool years, and probably beyond, highlighting a continuity between pre- and peri-natal life and subsequent development, and pointing to an atypical developmental trajectory in this population compared to fullterms (different rates of development, different strategies employed, and differences in the relationships among linguistic abilities).

Neural substrates of letter fluency processing in young adults who were born very preterm: alterations in frontal and striatal regions

Several studies have described poorer performance in executive-type tasks in individuals who were born very preterm compared to controls. As there is evidence that high-order executive functions may be underpinned by neuronal activity in frontal-striatal circuits, we investigated with functional MRI a group of young adults who were born very preterm (n=28, gestational age <33 weeks) and controls (n=26) in order to detect possible alterations in brain activation during completion of a letter fluency task with differential cognitive loading ("easy" and "hard" letter trials). Structural MRI data were also collected to clarify whether any functional changes were associated with structural brain volume changes. Group membership, level of task difficulty and gestational age had significant effects on brain activation. In the absence of significant between-group differences in task performance, during "easy" letter trials, very preterm-born individuals showed attenuated activation in anterior cingulate gyrus, right caudate nucleus and left inferior frontal gyrus compared to controls. During "hard" letter trials, very preterm-born individuals showed both decreased and increased BOLD signal compared to controls, in left middle frontal and anterior cingulate gyrus, respectively. BOLD signal in caudate nucleus and anterior cingulate gyrus, in regions with peaks close to areas where between-group differences were observed, was linearly associated with gestational age. Analysis of structural MRI data showed altered grey matter distribution in the preterm-born group compared to controls. However, fMRI results were only partly explained by structural changes, and may reflect processes of functional plasticity for the successful completion of executive-type operations.

Habilidades do desenvolvimento de prematuros

OBJETIVO: verificar o desempenho de habilidades do desenvolvimento linguístico, cognitivo, motor, de autocuidados e socialização em crianças prematuras. MÉTODOS: participaram 30 crianças nascidas prematuras, de ambos os sexos de seis a 24 meses. Os procedimentos de avaliação constaram de uma entrevista de anamnese e da aplicação do Inventário Portage Operacionalizado (IPO) (Wilhiams & Aiello, 2001). As crianças foram divididas em dois grupos, conforme a faixa etária, para análise estatística dos dados, considerando as idades de seis a 11 meses e de 12 a 24 meses. A análise dos dados foi realizada por meio da aplicação do teste Manny-Whitney comparando os valores obtidos no grupo de crianças prematuras com escores previstos para crianças típicas. RESULTADOS: os resultados indicam que a área mais defasada do grupo na faixa etária de seis a 12 meses foi à linguística e autocuidados e na faixa etária de 12 a 24 meses as áreas mais defasadas foram linguística, cognitiva e de autocuidados. CONCLUSÃO: ressalta-se a necessidade de um acompanhamento rigoroso de recém-nascidos prematuros, por meio do desenvolvimento de programas de acompanhamento e por uma equipe multidisciplinar para promover a detecção e intervenção precoce, minimizando assim o impacto de problemas no desenvolvimento global destas crianças.

Alterations in functional connectivity for language in prematurely born adolescents

Recent data suggest recovery of language systems but persistent structural abnormalities in the prematurely born. We tested the hypothesis that subjects who were born prematurely develop alternative networks for processing language. Subjects who were born prematurely (n = 22; 600–1250 g birth weight), without neonatal brain injury on neonatal cranial ultrasound, and 26 term control subjects were examined with a functional magnetic resonance imaging (fMRI) semantic association task, the Wechsler Intelligence Scale for Children-III (WISC-III) and the Clinical Evaluation of Language Fundamentals (CELF). In-magnet task accuracy and response times were calculated, and fMRI data were evaluated for the effect of group on blood oxygen level dependent (BOLD) activation, the correlation between task accuracy and activation and the functional connectivity between regions activating to task. Although there were differences in verbal IQ and CELF scores between the preterm (PT) and term control groups, there were no significant differences for either accuracy or response time for the in-magnet task. Both groups activated classic semantic processing areas including the left superior and middle temporal gyri and inferior frontal gyrus, and there was no significant difference in activation patterns between groups. Clear differences between the groups were observed in the correlation between task accuracy and activation to task at P< 0.01, corrected for multiple comparisons. Left inferior frontal gyrus correlated with accuracy only for term controls and left sensory motor areas correlated with accuracy only for PT subjects. Left middle temporal gyri correlated with task accuracy for both groups. Connectivity analyses at P< 0.001 revealed the importance of a circuit between left middle temporal gyri and inferior frontal gyrus for both groups. In addition, the PT subjects evidenced greater connectivity between traditional language areas and sensory motor areas but significantly fewer correlated areas within the frontal lobes when compared to term controls. We conclude that at 12 years of age, children born prematurely and children born at term had no difference in performance on a simple lexical semantic processing task and activated similar areas. Connectivity analyses, however, suggested that PT subjects rely upon different neural pathways for lexical semantic processing when compared to term controls. Plasticity in network connections may provide the substrate for improving language skills in the prematurely born.

School performance of adolescents born preterm: neuropsychological and background correlates

In this longitudinal study the development of preterm and control children was followed from infancy until adolescence. School performance at the age of 16 in subjects born very preterm with a gestational age (GA) of <or= 32 weeks was compared with the performance of adolescents born full-term. None of the subjects had major disabilities. The study groups performed similarly in most school subjects, including mathematics, the second foreign language and the native language (Finnish). Subjects in the preterm group achieved significantly higher grade points in the first foreign language than control subjects. In particular, the difference was evident between the preterm and control boys. The extremely preterm group with a GA <or= 29 weeks did not differ from the more mature group with a GA between 30 and 32 weeks in terms of the school grade points. Verbal and performance scale IQs as assessed at the age of 9 were of primary importance in predicting school success in adolescence. The results suggest a good outcome, measured by school grade scores at 16 years of age, of the subjects born very preterm.

Understanding language and cognitive deficits in very low birth weight children

Very-low-birth-weight infants are at much higher risk for cognitive and language delays but the nature of such deficits is not clearly understood. Given increasing rates of prematurity and infants born very-low-birth-weight, examination of mechanisms that underlie poorer developmental outcome is essential. We investigated language and cognitive abilities in very-low and normal birth-weight infants to determine whether performance differences were due to poorer global cognitive performance or to deficits in specific processing abilities. Thirty-two very-low and 32 normal birth-weight infants received visual and auditory-visual habituation recognition-memory tasks, and standardized language and cognitive assessments. Very-low-birth-weight infants performed more poorly on visual and auditory-visual habituation tasks and scored lower than controls on cognitive and language measures. These findings suggest that differences in language abilities in very-low-birth-weight children may be part of a global deficit that impacts many areas of cognitive functioning rather than a specific impairment in rapid auditory processing.

Corpus callosum and prefrontal functions in adolescents with history of very preterm birth

Very preterm (VPT) birth can account for thinning of the corpus callosum and poorer cognitive performance. Research findings about preterm and VPT adolescents usually describe a small posterior corpus callosum, although our research group has also found reductions of the anterior part, specifically the genu. The aim of the present study was to investigate the functional implications of this concrete reduction. Fifty-two VPT adolescents were compared with 52 adolescents born at term; there were no significant differences in age and gender, and socioeconomic status was similar between the groups. All participants underwent a magnetic resonance imaging (MRI) study and assessment of prefrontal functioning and vocabulary. The VPT group showed significant reductions of the genu, isthmus and splenium, as well as a significantly worse performance on category verbal fluency, executive functions, everyday memory and vocabulary. Although several parts of the corpus callosum correlated with some prefrontal functions, the genu was the part which principally explained these correlations. The subtest Vocabulary only correlated with the splenium. The relationship between genu and prefrontal functions and between splenium and vocabulary may be due to the fact that these parts of the corpus callosum connect prefrontal and posterior parietal cortex, respectively. The work presented here provides evidence of specific associations between reductions in the anterior corpus callosum (genu) and lower prefrontal functioning in VPT adolescents.