Children with differing developmental trajectories of prelinguistic communication skills: language and working memory at age 5

Maternal occupational noise exposure during pregnancy and children's early language acquisition

INTRODUCTION

Noise exposure during pregnancy may affect a child's auditory system, which may disturb fetal learning and language development. We examined the impact of occupational noise exposure during pregnancy on children's language acquisition at the age of one.

METHODS

A cohort study was conducted among women working in the food industry, as kindergarten teachers, musicians, dental nurses, or pharmacists who had a child aged <1 year. The analyses covered 408 mother-child pairs. Language acquisition was measured using the Infant-Toddler Checklist. An occupational hygienist assessed noise exposure individually as no (N = 180), low (70-78 dB; N = 108) or moderate/high exposure (>79 dB; N = 120).

RESULTS

Among the boys, the adjusted mean differences in language acquisition scores were -0.4 (95% CI -2.5, 1.8) for low, and -0.7 (95% CI -2.9, 1.4) for moderate/high exposure compared to no exposure. Among the girls the respective scores were +0.1 (95% CI -2.2, 2.5) and -0.1 (95% CI -2.3, 2.2). Among the children of kindergarten teachers, who were mainly exposed to human noise, low or moderate exposure was associated with lower language acquisition scores. The adjusted mean differences were -3.8 (95% CI -7.2, -0.4) for low and -4.9 (95% CI -8.6, -1.2) for moderate exposure.

CONCLUSIONS

In general, we did not detect an association between maternal noise exposure and children's language acquisition among one-year-old children. However, the children of kindergarten teachers exposed to human noise had lower language acquisition scores than the children of the non-exposed participants. These suggestive findings merit further investigation by level and type of exposure.

Associated functional network development and language abilities in children

During childhood, the brain is gradually converging to the efficient functional architecture observed in adults. How the brain's functional architecture evolves with age, particularly in young children, is however, not well understood. We examined the functional connectivity of the core language regions, in association with cortical growth and language abilities, in 175 young children in the age range of 4 to 9 years. We analyzed the brain's developmental changes using resting-state functional and T1-weighted structural magnetic resonance imaging data. The results showed increased functional connectivity strength with age between the pars triangularis of the left inferior frontal gyrus and left temporoparietal regions (cohen's d = 0.54, CI: 0.24 - 0.84), associated with children's language abilities. Stronger functional connectivity between bilateral prefrontal and temporoparietal regions was associated with better language abilities regardless of age. In addition, the stronger functional connectivity between the left inferior frontal and temporoparietal regions was associated with larger surface area and thinner cortical thickness in these regions, which in turn was associated with superior language abilities. Thus, using functional and structural brain indices, coupled with behavioral measures, we elucidate the association of functional language network development, language ability, and cortical growth, thereby adding to our understanding of the neural basis of language acquisition in young children.

Early vocabulary development: Relationships with prelinguistic skills and early social-emotional/behavioral problems and competencies

The aim of this longitudinal study was to investigate early vocabulary development and its relationships with prelinguistic communication skills and social-emotional/behavioral (SEB¹) problems and competencies. The participants were 58 healthy Finnish-speaking children (30 girls, 28 boys). First, the concurrent relationships were investigated at the age of 18 months. Second, the relationships between prelinguistic communication skills and SEB problems and competencies at 18 months, and subsequent vocabulary scores at 24 and 30 months, were examined. Parental reports on early vocabulary (MacArthur Communicative Developmental Inventories; MCDI), prelinguistic communication skills (The Infant-Toddler Checklist of the Communication and Symbolic Behavior Scales Developmental Profile; ITC), SEB problems and competencies (Brief Infant-Toddler Social and Emotional Assessment; BITSEA) were gathered. Compared to boys, girls scored significantly higher on ITC Speech Composite at 18 months and expressive vocabulary measures at 18, 24, and 30 months. Vocabulary, as well as prelinguistic communication measures, correlated with SEB competencies at 18 months. Furthermore, vocabulary, as well as ITC Symbolic Composite and Total Score, correlated negatively with externalizing problem and SEB Total Problem scores. With regard to subsequent vocabulary development, all of the prelinguistic communication measures at 18 months correlated with vocabulary at 24 and 30 months. However, when accounted for gender and earlier vocabulary, only the associations with ITC Speech Composite and Total Score at 24 months remained significant. SEB Competencies at 18 months correlated positively, while externalizing problems at 18 months correlated negatively with vocabulary at 24 and 30 months, however, these associations did not remain significant, when accounted for gender and earlier vocabulary.

Continuity From Prelinguistic Communication to Later Language Ability: A Follow-Up Study From Infancy to Early School Age

PURPOSE

This longitudinal study examined the development of prelinguistic skills and the continuity of communication and language from the prelinguistic stage to school age.

METHOD

Prelinguistic communication of 427 Finnish children was followed repeatedly from 6 to 18 months of age (n = 203-322 at ages 6, 9, 12, 15, and 18 months), and its associations with language ability at ages 2;0 (n = 104), 3;0 (n = 112), 4;7 (n = 253), 5;3 (n = 102), and 7;9 (n = 236) were examined using latent growth curve modeling.

RESULTS

Prelinguistic development across several skills emerged as a rather stable intraindividual characteristic during the first 2 years of life. Continuity from prelinguistic development to later language ability was indicated. The common level and growth of prelinguistic skills were significant predictors of language ability between ages 2;0 (years;months) and 7;9; the percentage explained varied between 10.5% and 53.3%. A slow pace of development across multiple skills, in particular, led to weaker language skills.

CONCLUSIONS

The results support (a) the idea of a developmental continuum from prelinguistic to linguistic ability and (b) the dimensional view of language ability by indicating that individual variations in early communication skills show consistency that extends beyond the toddler years. Our results also advocate developmental surveillance of early communication by emphasizing the significance of growth in predicting language development.

Interrelationships Between Working Memory, Processing Speed, and Language Development in the Age Range 2-4 years

PURPOSE

This study explored associations between working memory and language in children aged 2-4 years.

METHOD

Seventy-seven children aged 24-30 months were assessed on tests measuring language, visual cognition, verbal working memory (VWM), phonological short-term memory (PSTM), and processing speed. A standardized test of receptive and expressive language was used as the outcomes measure 18 months later.

RESULTS

There were moderate-to-strong longitudinal bivariate relationships between the 3 processing measures and language outcomes. Early VWM showed the strongest bivariate relationship with both later expressive (r = .71) and receptive language (r = .72). In a hierarchical multiple regression analysis, adding early VWM, PSTM, and processing speed improved prediction of receptive and expressive language outcomes (12%-13% additional variance) compared with models consisting only of early receptive or expressive language, parent education, and age.

CONCLUSIONS

Unique associations in hierarchical regression analyses were demonstrated between VWM at age two years and receptive and expressive language skills at age four, and between early processing speed and later receptive language. However, early PSTM did not predict unique variance in language outcomes, as it shared variance with other measures.

Longitudinal changes in resting-state fMRI from age 5 to age 6years covary with language development

Resting-state functional magnetic resonance imaging is a powerful technique to study the whole-brain neural connectivity that underlies cognitive systems. The present study aimed to define the changes in neural connectivity in their relation to language development. Longitudinal resting-state functional data were acquired from a cohort of preschool children at age 5 and one year later, and changes in functional connectivity were correlated with language performance in sentence comprehension. For this, degree centrality, a voxel-based network measure, was used to assess age-related differences in connectivity at the whole-brain level. Increases in connectivity with age were found selectively in a cluster within the left posterior superior temporal gyrus and sulcus (STG/STS). In order to further specify the connection changes, a secondary seed-based functional connectivity analysis on this very cluster was performed. The correlations between resting-state functional connectivity (RSFC) and language performance revealed developmental effects with age and, importantly, also dependent on the advancement in sentence comprehension ability over time. In children with greater advancement in language abilities, the behavioral improvement was positively correlated with RSFC increase between left posterior STG/STS and other regions of the language network, i.e., left and right inferior frontal cortex. The age-related changes observed in this study provide evidence for alterations in the language network as language develops and demonstrates the viability of this approach for the investigation of normal and aberrant language development.

Associations between toddler-age communication and kindergarten-age self-regulatory skills

PURPOSE

In this study, the authors aimed at gaining understanding on the associations of different types of early language and communication profiles with later self-regulation skills by using longitudinal data from toddler age to kindergarten age.

METHOD

Children with early language profiles representing expressive delay, broad delay (i.e., expressive, social, and/or symbolic), and typical language development were compared in domains of kindergarten-age executive and regulative skills (attentional/executive functions, regulation of emotions and behavioral activity, and social skills) assessed with parental questionnaires.

RESULTS

Children with delay in toddler-age language development demonstrated poorer kindergarten-age self-regulation skills than children with typical early language development. Broad early language delays were associated with compromised social skills and attentional/executive functions, and early expressive delays were associated with a generally lower level of kindergarten-age executive and regulative skills. Regression analyses showed that both earlier and concurrent language had an effect especially on the attentional/executive functions.

CONCLUSIONS

The findings suggest that different aspects of toddler-age language have differential associations with later self-regulation. Possible mechanisms linking early language development to later self-regulative development are discussed.