Relationship between early language skills and the development of inattention/hyperactivity symptoms during the preschool period: Results of the EDEN mother-child cohort

Genome-Wide Analyses of Vocabulary Size in Infancy and Toddlerhood: Associations With Attention-Deficit/Hyperactivity Disorder, Literacy, and Cognition-Related Traits

BACKGROUND

The number of words children produce (expressive vocabulary) and understand (receptive vocabulary) changes rapidly during early development, partially due to genetic factors. Here, we performed a meta-genome-wide association study of vocabulary acquisition and investigated polygenic overlap with literacy, cognition, developmental phenotypes, and neurodevelopmental conditions, including attention-deficit/hyperactivity disorder (ADHD).

METHODS

We studied 37,913 parent-reported vocabulary size measures (English, Dutch, Danish) for 17,298 children of European descent. Meta-analyses were performed for early-phase expressive (infancy, 15-18 months), late-phase expressive (toddlerhood, 24-38 months), and late-phase receptive (toddlerhood, 24-38 months) vocabulary. Subsequently, we estimated single nucleotide polymorphism-based heritability (SNP-h2) and genetic correlations (rg) and modeled underlying factor structures with multivariate models.

RESULTS

Early-life vocabulary size was modestly heritable (SNP-h2 = 0.08-0.24). Genetic overlap between infant expressive and toddler receptive vocabulary was negligible (rg = 0.07), although each measure was moderately related to toddler expressive vocabulary (rg = 0.69 and rg = 0.67, respectively), suggesting a multifactorial genetic architecture. Both infant and toddler expressive vocabulary were genetically linked to literacy (e.g., spelling: rg = 0.58 and rg = 0.79, respectively), underlining genetic similarity. However, a genetic association of early-life vocabulary with educational attainment and intelligence emerged only during toddlerhood (e.g., receptive vocabulary and intelligence: rg = 0.36). Increased ADHD risk was genetically associated with larger infant expressive vocabulary (rg = 0.23). Multivariate genetic models in the ALSPAC (Avon Longitudinal Study of Parents and Children) cohort confirmed this finding for ADHD symptoms (e.g., at age 13; rg = 0.54) but showed that the association effect reversed for toddler receptive vocabulary (rg = -0.74), highlighting developmental heterogeneity.

CONCLUSIONS

The genetic architecture of early-life vocabulary changes during development, shaping polygenic association patterns with later-life ADHD, literacy, and cognition-related traits.

Word-Finding Difficulties as a Prominent Early Finding in a Later Diagnosis of Attention Deficit Hyperactivity Disorder

OBJECTIVE

 Attention deficit hyperactivity disorder (ADHD) is a common neuropsychological disorder primarily diagnosed in childhood. Early intervention was found to significantly improve developmental outcomes, implicating on the role of early identification of ADHD markers. In the current study, we explored the developmental history of children referred to neurological assessment to identify early ADHD predictors.

METHODS

 A total of 92 children and adolescents (41 females) recruited at a pediatric neurology clinic, with suspected ADHD (n = 39) or other neurological difficulties (n = 53) such as headaches, seizures, tic disorders, orthostatic hypotension, postischemic stroke, intermittent pain, and vasovagal syncope. Developmental history information was obtained from caregivers, and evaluation for possible ADHD was performed. Developmental details were compared between children with and without current ADHD diagnosis.

RESULTS

 Word-finding difficulties (WFDs) in preschool age was reported in 30.4% of the sample. Among children diagnosed with ADHD, 43% had WFDs history, compared with only 5% in children without ADHD. Among children with WFDs history, 93% were later diagnosed with ADHD compared with 42% in children without WFDs history. The relationship between WFDs and ADHD was significant (chi-square test [1, N = 92] = 20.478, p < 0.0001), and a logistic regression model demonstrated that asides from a family history of ADHD, the strongest predictor for ADHD in school age children was a history of WFDs.

CONCLUSION

 Preliminary evidence supports a predictive link between preschool WFDs and later ADHD diagnosis, highlighting the importance of early WFDs clinical attention.

Do Language-Related Cognitive Capacities Help Predict Adjustment in Children with Attention-Deficit/Hyperactivity Disorder?

The goal of this paper was to examine the role that language-related cognitive capacities (LRCC) might play in explaining adjustment of 7 to 12 year-old children (M_age = 9.24; SD_age = 0.91) with and without ADHD. The sample was comprised of 178 children with ADHD and 86 typically-developing children (77.3% male; 81.4% White; 9.5% Black; 1.9% Hispanic; 0.8% Asian; 5.7% multiracial; 0.8% did not report race/ethnicity). Using simultaneous regression, we examined whether LRCC accounted for unique variance in achievement, attention problems, oppositional problems, conduct problems, and internalizing, over and above what standard covariates and ADHD diagnostic status could explain. Finally, we examined LRCC as a mediator of the relation between ADHD diagnostic status and these adjustment measures. Results indicated that LRCC significantly predicted 6 of 7 and partially mediated 5 of 7 measures, suggesting that language-related constructs warrant greater attention in diagnosis and treatment of ADHD.

Language Problems and ADHD Behaviors: Unique and Interactive Associations with School Readiness in a Socioeconomically Disadvantaged Preschool Sample

This study examined the unique and interactive effects of receptive language ability and ADHD behaviors on six school readiness outcomes, over and above the effects of socioeconomic status, in 49 preschoolers (M_age = 3.98, SD_age = .58; 53.06% female) recruited from Head Start-affiliated classrooms. Hierarchical regression analyses revealed unique positive associations between receptive language ability and cognitive and mathematics readiness, and unique negative associations between ADHD behaviors and social-emotional, physical, cognitive, and literacy readiness. Moderation analyses indicated that at higher, but not lower, levels of ADHD behaviors, lower receptive language ability was associated with lower social-emotional readiness. Results highlight that, when considered together, children's receptive language ability and ADHD behaviors vary in how they predict school readiness. Further, results provide preliminary evidence for ADHD behaviors as a risk factor in the association between receptive language deficits and social-emotional school readiness. Educational and clinical practice implications are discussed.

Factors structuring lexical development in toddlers: The effects of parental education, language exposure, and age

A growing body of research suggests that individual variation in young children's word comprehension (indexed by response times and accuracy) is structured and meaningful. In this paper, we assess how children's word comprehension correlates with three factors: socio-economic status (indexed by maternal education), lingual status (based on language exposure), and age. We present results from 91 2- to 3-year-old children using a paired forced-choice task built on a child-friendly touch screen. Effects associated with maternal education and exposure to the tested language (French) were small, and they were greater for accuracy than response times. This pattern of results is compatible with an interpretation whereby the greatest effects of these two variables are on cumulative knowledge (vocabulary size) rather than on processing. Effects for age were larger and affected both accuracy and response times. Finally, response time variation did not mediate the effects of socio-economic status on accuracy or vice versa.

Systematic Review and Meta-analysis: The Science of Early-Life Precursors and Interventions for Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

To evaluate which early neurocognitive and behavioral precursors are associated with the development of attention-deficit/hyperactivity disorder (ADHD) and whether these are currently targeted in early interventions.

METHOD

We conducted 2 systematic reviews and meta-analyses of empirical studies to examine the following: (1) early-life (0-5 years) neurocognitive and behavioral precursors associated with familial likelihood for ADHD, an early ADHD diagnosis/elevated ADHD symptoms, and/or the presence of later-childhood ADHD; and (2) interventions delivered to children aged 0 to 5 years targeting the identified precursors or measuring these as outcomes. Standardized mean differences (Hedges' g) and pre-post-treatment change scores (SMD) were computed.

RESULTS

A total of 149 studies (165,095 participants) investigating 8 neurocognitive and behavioral domains met inclusion criteria for part 1. Multi-level random-effects meta-analyses on 136 studies revealed significant associations between ADHD and poorer cognitive (g = -0.46 [95% CIs: -0.59, -0.33]), motor (g = -0.35 [CIs: -0.48, -0.21]) and language (g = -0.43 [CIs: -0.66, -0.19]) development, social (g = 0.23 [CIs: 0.03, 0.43]) and emotional (g = 0.46 [CIs: 0.33, 0.58]) difficulties, early regulatory (g = 0.30 [CIs: 0.18, 0.43]) and sleep (g = 0.29 [CIs: 0.14, 0.44]) problems, sensory atypicalities (g = 0.52 [CIs: 0.16, 0.88]), elevated activity levels (g = 0.54 [CIs: 0.37, 0.72]), and executive function difficulties (g = 0.34 [CIs: 0.05, 0.64] to -0.87 [CIs: -1.35, -0.40]). A total of 32 trials (28 randomized, 4 nonrandomized, 3,848 participants) testing early interventions that targeted the identified precursors met inclusion criteria for part 2. Multi-level random-effects meta-analyses on 22 studies revealed significant intervention-related improvements in ADHD symptoms (SMD = 0.43 [CIs: 0.22, 0.64]) and working memory (SMD = 0.37 [CIs: 0.06, 0.69]).

CONCLUSION

Children aged 0 to 5 years with current or later-emerging ADHD are likely to experience difficulties in multiple neurocognitive/behavioral functions. Early interventions show some effectiveness in reducing ADHD symptoms, but their effects on neurocognitive/behavioral difficulties require further study.

Maternal depressive symptoms and maternal child-directed speech: A systematic review

BACKGROUND

Up to 1 in 5 children are exposed to maternal depressive symptoms. Children exposed to maternal depressive symptoms have poorer language skills than children not exposed to maternal depressive symptoms. Due to the crucial role of children's language skills in school readiness and academic achievement, it is imperative to understand the factors that underlie the relation between maternal depressive symptoms and children's language skills. Previous reviews have examined the mechanistic role of social-pragmatic features of mother-child interactions. However, the literature on the relation between maternal depressive symptoms and data-providing aspects of mother-child interactions, including child-directed speech, has yet to be consolidated. In this systematic review, we present maternal child-directed speech as a potential pathway through which maternal depressive symptoms influence children's language skills.

METHODS

Following PRISMA guidelines, three database searches produced 546 articles related to maternal depressive symptoms, child-directed speech, and children's language skills, ten of which examined the relation between maternal depressive symptoms and child-directed speech.

RESULTS

Findings revealed that increases in maternal depressive symptoms may be associated with decreases in amount of child-directed speech but not necessarily with decreases in the complexity of child-directed speech.

LIMITATIONS

The studies in this review varied in sample size, the inclusion of important sociodemographic factors, and the operationalization of depression and child-directed speech, thereby limiting conclusions, especially about whether maternal depressive symptoms are associated with the complexity of child-directed speech.

CONCLUSIONS

This review has implications for prevention and intervention efforts aimed at optimizing children's language skills; child-directed speech is modifiable, and mothers experiencing depressive symptoms may benefit from resources encouraging rich child-directed speech.

The epidemiology of cognitive development

The epidemiology of cognitive development is an approach essentially based on large observational studies, which examines individual differences in cognitive abilities throughout childhood and their determinants. Although different in terms of methodology and main interests from developmental psychology, cognitive epidemiology offers complementary viewpoints on cognitive development and addresses fundamental research questions of interest to developmental psychologists. The present paper depicts the contributions of the epidemiological approach to the field of cognitive development and highlights the methodological advances that have made such contributions possible. We discuss the stability and developmental trajectories of cognitive functions, their main predictors, the complex interplay between environmental and genetic predictors, and the relationships between the different domains of cognition from birth to adulthood.

Effects of depression and cognitive impairment on quality of life in older adults with schizophrenia spectrum disorder: Results from a multicenter study

BACKGROUND

Little is known about the respective effects of depression and cognitive impairment on quality of life among older adults with schizophrenia spectrum disorder.

METHODS

We used data from the Cohort of individuals with Schizophrenia Aged 55-years or more (CSA) study, a large multicenter sample of older adults with schizophrenia or schizoaffective disorder (N = 353). Quality of life (QoL), depression and cognitive impairment were assessed using the Quality of Life Scale (QLS), the Center of Epidemiologic Studies Depression scale and the Mini-Mental State Examination, respectively. We used structural equation modeling to examine the shared and specific effects of depression and cognitive impairment on QoL, while adjusting for sociodemographic characteristics, general medical conditions, psychotropic medications and the duration of the disorder.

RESULTS

Depression and cognitive impairment were positively associated (r = 0.24, p < 0.01) and both independently and negatively impacted on QoL (standardized β = -0.41 and β = -0.32, both p < 0.01) and on each QLS quality-of-life domains, except for depression on instrumental role and cognitive impairment on interpersonal relations in the sensitivity analyses excluding respondents with any missing data. Effects of depression and cognitive impairment on QoL were not due to specific depressive symptoms or specific cognitive domains, but rather mediated through two broad dimensions representing the shared effects across all depressive symptoms and all cognitive deficits, respectively.

LIMITATIONS

Because of the cross-sectional design of this study, measures of association do not imply causal associations.

CONCLUSIONS

Mechanisms underlying these two broad dimensions should be considered as important potential targets to improve quality of life of this vulnerable population.

The Effect of Older Siblings on Language Development as a Function of Age Difference and Sex

The number of older siblings a child has is negatively correlated with the child’s verbal skills, perhaps because of competition for parents’ attention. In the current study, we examined the role of siblings’ sex and age gap as moderating factors, reasoning that they affect older siblings’ tendency to compensate for reduced parental attention. We hypothesized that children with an older sister have better language abilities than children with an older brother, especially when there is a large age gap between the two siblings. We reanalyzed data from the EDEN cohort ( N = 1,154) and found that children with an older sister had better language skills than those with an older brother. Contrary to predictions, results showed that the age gap between siblings was not associated with language skills and did not interact with sex. Results suggest that the negative effect of older siblings on language development may be entirely due to the role of older brothers. Our findings invite further research on the mechanisms involved in this effect.

Association of language, behavior, and parental stress in young children with a language disorder

BACKGROUND

Several studies show that language problems, child behavior problems, and parental stress can co-occur in children. Still, little is known about how these domains are related in toddlers with a language disorder (LD).

AIMS

This study examined relations between language problems, child behaviour problems, and parental stress in toddlers with LD and if these relations differ for children with different types of LD.

METHOD

Data of 185 children with LD (mean age 38 months) were collected using Routine Outcome Monitoring. Children were divided into two groups: presence of receptive and expressive problems (REP) and expressive problems only (EP). Relations were analyzed using Structural Equation Modeling.

RESULTS

A better receptive language was associated with less teacher-reported internalizing and externalizing problems. A better expressive vocabulary was associated with more parent-reported internalizing problems and more teacher-reported externalizing problems. No relation was found between language and parental stress. Associations between language, behavior, and parental stress did not differ for children with REP or children with EP.

CONCLUSIONS

Our study shows that when specific language domains are examined, the pattern of associations between language and behavior becomes more complex, because relations exist between specific language domains and behavior, but not between all of them.

Discovery of the first genome-wide significant risk loci for attention deficit/hyperactivity disorder

Attention deficit/hyperactivity disorder (ADHD) is a highly heritable childhood behavioral disorder affecting 5% of children and 2.5% of adults. Common genetic variants contribute substantially to ADHD susceptibility, but no variants have been robustly associated with ADHD. We report a genome-wide association meta-analysis of 20,183 individuals diagnosed with ADHD and 35,191 controls that identifies variants surpassing genome-wide significance in 12 independent loci, finding important new information about the underlying biology of ADHD. Associations are enriched in evolutionarily constrained genomic regions and loss-of-function intolerant genes and around brain-expressed regulatory marks. Analyses of three replication studies: a cohort of individuals diagnosed with ADHD, a self-reported ADHD sample and a meta-analysis of quantitative measures of ADHD symptoms in the population, support these findings while highlighting study-specific differences on genetic overlap with educational attainment. Strong concordance with GWAS of quantitative population measures of ADHD symptoms supports that clinical diagnosis of ADHD is an extreme expression of continuous heritable traits.

Discovery of the first genome-wide significant risk loci for attention deficit/hyperactivity disorder

Attention deficit/hyperactivity disorder (ADHD) is a highly heritable childhood behavioral disorder affecting 5% of children and 2.5% of adults. Common genetic variants contribute substantially to ADHD susceptibility, but no variants have been robustly associated with ADHD. We report a genome-wide association meta-analysis of 20,183 individuals diagnosed with ADHD and 35,191 controls that identifies variants surpassing genome-wide significance in 12 independent loci, finding important new information about the underlying biology of ADHD. Associations are enriched in evolutionarily constrained genomic regions and loss-of-function intolerant genes and around brain-expressed regulatory marks. Analyses of three replication studies: a cohort of individuals diagnosed with ADHD, a self-reported ADHD sample and a meta-analysis of quantitative measures of ADHD symptoms in the population, support these findings while highlighting study-specific differences on genetic overlap with educational attainment. Strong concordance with GWAS of quantitative population measures of ADHD symptoms supports that clinical diagnosis of ADHD is an extreme expression of continuous heritable traits.