Cognitive development in 7- to 24-month-old extremely/very-to-moderately/late preterm and full-term born infants: The mediating role of focused attention

Risk of Developmental Disorders in Children Born at 32 to 38 Weeks' Gestation: A Meta-Analysis

CONTEXT

Very preterm birth (<32 weeks) is associated with increased risk of developmental disorders. Emerging evidence suggests children born 32 to 38 weeks might also be at risk.

OBJECTIVES

To determine the relative risk and prevalence of being diagnosed with, or screening positive for, developmental disorders in children born moderately preterm, late preterm, and early term compared with term (≥37 weeks) or full term (39-40/41 weeks).

DATA SOURCES

Medline, Embase, Psychinfo, Cumulative Index of Nursing, and Allied Health Literature.

STUDY SELECTION

Reported ≥1 developmental disorder, provided estimates for children born 32 to 38 weeks.

DATA EXTRACTION

A single reviewer extracted data; a 20% sample was second checked. Data were pooled using random-effects meta-analyses.

RESULTS

Seventy six studies were included. Compared with term born children, there was increased risk of most developmental disorders, particularly in the moderately preterm group, but also in late preterm and early term groups: the relative risk of cerebral palsy was, for 32 to 33 weeks: 14.1 (95% confidence intervals [CI]: 12.3-16.0), 34 to 36 weeks: 3.52 (95% CI: 3.16-3.92) and 37 to 38 weeks: 1.44 (95% CI: 1.32-1.58).

LIMITATIONS

Studies assessed children at different ages using varied criteria. The majority were from economically developed countries. All were published in English. Data were variably sparse; subgroup comparisons were sometimes based on single studies.

CONCLUSIONS

Children born moderately preterm are at increased risk of being diagnosed with or screening positive for developmental disorders compared with term born children. This association is also demonstrated in late preterm and early term groups but effect sizes are smaller.

Mild brain lesions do not affect brain volumes in moderate-late preterm infants

PURPOSE

It is unknown whether frequently occurring mild brain lesions affect brain volumes in moderate (MP²; 32⁺⁰-33⁺⁶ weeks' gestation) and late (LP³; 34⁺⁰-35⁺⁶ weeks' gestation) preterm infants. Therefore, we aimed to investigate the effect of mild brain lesions on brain volumes in moderate-late preterm (MLPT⁴) infants and to compare brain volumes between MP and LP infants.

METHODS

From August 2017 to November 2019, eligible MLPT infants born at Isala Women and Children's Hospital were enrolled in a prospective cohort study (Brain Imaging in Moderate-late Preterm infants 'BIMP-study'). MRI was performed around term equivalent age (TEA⁵). MRI scans were assessed for (mild) brain lesions. T2-weighted images were used for automatic segmentation of eight brain structures. Linear regression analysis was performed to compare absolute and relative brain volumes between infants with and without mild brain lesions and between MP and LP infants.

RESULTS

36 MP and 68 LP infants were included. In infants with mild brain lesions, intracranial volume (B = 27.4 cm³, p = 0.02), cerebrospinal fluid (B = 8.78 cm³, p = 0.01) and cerebellar volumes (B = 1.70 cm³, p = 0.03) were significantly larger compared to infants without mild brain lesions. After correction for weight and postmenstrual age at MRI, these volumes were no longer significantly different. LP infants had larger brain volumes than MP infants, but differences were not significant. Relative brain volumes showed no significant differences in both analyses.

CONCLUSION

Neither having mild brain lesions, nor being born moderate prematurely affected brain volumes at TEA in MLPT infants.

Exploring predictors at toddler age of distinct profiles of attentional functioning in 6-year-old children born moderate-to-late preterm and full term

OBJECTIVE

Examining relationships of toddler abilities in attention, cognitive, motor, and language development, and behavioral problems, with distinct attention profiles at 6 years of age in children born moderate-to-late preterm and full term.

METHOD

Longitudinal study with a cohort of 88 moderate-to-late preterm and 83 full term born children. At 18 months attention abilities were assessed. At 24 months cognitive, motor, and language development was examined and behavioral problems were screened. At 6 years ten measures of attention were administered, which were used to classify children in one of four attentional functioning profiles (normal attention, overall poorer attention, poorer cognitive attention, and behavioral attention problems). Performance at 18 and 24 months was examined in relation to these four distinct attention profiles, as well as in relation to normal (first profile) versus subaverage attention (second, third, and fourth profiles) using multinomial logistic regressions.

RESULTS

Orienting and alerting attention, and receptive language were related to distinct attention profiles. Specifically, children with an overall poorer attention profile at 6 years were differentiated by lower orienting attention and receptive language scores at toddler age, while those with a poorer cognitive attention profile showed lower early alerting attention at 18 months. Children with a behavioral attention problems profile at 6 years were differentiated by lower orienting attention but higher alerting attention scores at toddler age. Orienting attention and receptive language, but not alerting attention, at toddler age were related to normal versus subaverage attention, with lower scores predicting subaverage attention.

CONCLUSIONS

Children at risk of poorer attentional functioning at school-age, expressed in distinct attention profiles, already showed differentiated functioning in attention abilities and in language comprehension as toddlers. Distinguishing distinct attention profiles could be important for future research and clinical practice, as is early monitoring of attention and language abilities in children at risk.

Very preterm infants engage in an intervention to train their control of attention: results from the feasibility study of the Attention Control Training (ACT) randomised trial

Background

Very premature birth (gestational age between 28 and 31 + 6 weeks) is associated with increased risk of cognitive delay and attention deficit disorder, which have been linked to anomalies in the development of executive functions (EFs) and their precursors. In particular, very preterm (VP) infants display anomalies in controlling attention and gathering task-relevant information. Early interventions that support attention control may be pivotal in providing a secure base for VP children’s later attainments. The Attention Control Training (ACT) is a cognitive training intervention that targets infants’ abilities to select visual information according to varying task demands but had not been tested in VP infants. We conducted a feasibility study to test the processes we intend to use in a trial delivering the ACT to VP infants.

Methods and design

We tested recruitment and retention of VP infants and their families in a randomised trial, as well as acceptability and completion of baseline and outcome measures. To evaluate these aims, we used descriptive quantitative statistics and qualitative methods to analyse feedback from infants’ caregivers. We also investigated the quality of eye-tracking data collected and indicators of infants’ engagement in the training, using descriptive statistics.

Results

Twelve VP infants were recruited, and 10 (83%) completed the study. Participants’ parents had high education attainment. The rate of completion of baseline and outcome measures was optimal. VP infants demonstrated engagement in the training, completing on average 84 min of training over three visits, and displaying improved performance during this training. Eye-tracking data quality was moderate, but this did not interfere with infants’ engagement in the training.

Discussion

The results suggest the ACT can be delivered to VP infants. However, challenges remain in recruitment of numerous and diverse samples. We discuss strategies to overcome these challenges informed by results of this study.

Trial registration

Registered Registration ID: NCT03896490. Retrospectively registered at Clinical Trials Protocol Registration and Results System (clinicaltrials.gov).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00809-z.

Preterm Birth and the Development of Visual Attention During the First 2 Years of Life: A Systematic Review and Meta-analysis

Importance

Preterm birth is associated with an increased risk for long-lasting attention deficits. Early-life markers of attention abnormalities have not been established to date but could provide insights into the pathogenesis of attention abnormalities and could help identify susceptible individuals.

Objective

To examine whether preterm birth is associated with visual attention impairments in early life, and if so, in which attention functions and at which developmental period during the first 2 years of life.

Data Sources

PubMed and PsycINFO were searched on November 17, 2019, to identify studies involving visual attention outcomes in infants born preterm vs full term.

Study Selection

Peer-reviewed studies from the past 50 years met the eligibility criteria if they directly assessed visual attention outcomes until the age of 2 years in generally healthy infants born preterm or full term. The selection process was conducted by 2 independent reviewers.

Data Extraction and Synthesis

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guideline was followed. Random-effects models were used to determine standardized mean differences. The risk of bias was assessed both within and between studies.

Main Outcomes and Measures

Five nascent indices of visual attention were analyzed, including very basic functions-namely, the abilities to follow and fixate on visual targets-and more complex functions, such as visual processing (ie, habituation), recognition memory (ie, novelty preference), and the ability to effortfully focus attention for learning.

Results

A total of 53 studies were included, with 69 effect sizes and assessing a total of 3998 infants (2047 born preterm and 1951 born full term; of the 3376 for whom sex was reported, 1693 [50.1%] were girls). Preterm birth was associated with impairments in various attention indices, including visual-following in infancy (Cohen d, -0.77; 95% CI, -1.23 to -0.31), latency to fixate (Cohen d, -0.18; 95% CI, -0.33 to -0.02), novelty preference (Cohen d, -0.20; 95% CI, -0.32 to -0.08), and focused attention (Cohen d, -0.28; 95% CI, -0.45 to -0.11). In the neonatal period, preterm birth was associated with superior visual-following (Cohen d, 0.22; 95% CI, 0.03 to 0.40), possibly owing to the additional extrauterine exposure to sensory stimulation. However, this early association waned rapidly in infancy (Cohen d, -0.77; 95% CI, -1.23 to -0.31).

Conclusions and Relevance

The findings suggest that preterm birth is associated with impingements to visual attention development in early life, as manifested in basic and then complex forms of attention. Advancements in neonatal care may underlie improvements found in the current era and accentuate several early protective factors.

Toddlers' Language Development: The Gradual Effect of Gestational Age, Attention Capacities, and Maternal Sensitivity

Language development in toddlerhood forms the foundation for speech and language comprehension throughout childhood. Children born moderately preterm are at increased risk for problems in receptive and expressive language functioning, and they may need specific support or interventions. To understand the underlying mechanisms of language development, an integrated model of gestational age, attention capacities, and maternal sensitivity was examined in relation to receptive and expressive language functioning in toddlerhood. Our sample included 221 children (gestational age between 32–41 + 6 weeks; 54.7% born moderately preterm; 51.6% boys; 69.1% highly educated mothers). At 18 months (corrected age), attention capacities were measured using an eye-tracking procedure and maternal sensitivity was observed during mother-child interaction. Language was assessed at 24 months (corrected age). Results showed children with a higher gestational age scored higher on receptive language. This association was direct, as well as indirect through the child’s alerting attention. Expressive language was related to maternal sensitivity. Gestational age and alerting attention capacities specifically were related to language comprehension, whereas maternal sensitivity was related to speech. As language comprehension and speech in toddlerhood show different associations with biological, child, contextual, and regulation factors, they should be viewed as separate constructs in research and practice.

Effortful control and attention as predictors of cognition in children born preterm

BACKGROUND

Preterm childbirth increases the risk of developmental problems. The aim of the present study was to examine the effects of temperament and attention on the cognition of school-age children who were born preterm, controlling for socioeconomic variables.

MATERIAL AND METHODS

The sample was composed of 50 six-year-old children who were born preterm with very low birth weight. The children were evaluated using the Wechsler Intelligence Scale for Children (WISC-III) and the Cancellation Attention Test. The mothers were interviewed using the Children's Behavior Questionnaire (CBQ). Statistical multiple linear regression analyses were performed.

RESULTS

70% of the children presented average or above-average full intellectual quotient (IQ). In the attention total score, 74% of the children were also within the average range or above. High verbal IQ associated with high maternal schooling explained 73% variability of the full IQ. High attention and maternal schooling, associated with children's temperament with more effortful control, explained 35% variability of the verbal IQ. High attention, associated with high maternal schooling and socioeconomic level, explained 37% variability of the performance IQ. The neonatal clinical variables (gestational age, birth weight, 5th-minute Apgar, and length of stay in neonatal intensive care unit (NICU) and hospital) were not predictors of cognitive outcomes.

CONCLUSION

The majority of the children who were born preterm presented average or above-average cognitive and attentional performances at school age, demonstrating potential resources for learning. Taken together, attention and temperament, associated with maternal schooling and socioeconomic status, were predictors of cognitive outcomes of children born preterm at school age.

Correlates of early cognition in infants with Down syndrome

BACKGROUND

While delays in cognitive development are detectable during early development in Down syndrome, the neuropsychological and biomedical underpinnings of cognitive skill acquisition in this population remain poorly understood.

METHOD

To explore this issue, 38 infants with Down syndrome [mean chronological age = 9.65 months; SD = 3.64] completed the Bayley Scales of Infant Development-III and a set of laboratory tasks that measured sustained attention (duration of visual attention during a 1-min object exploration task), attention shifting (mean latency to shift attention on an alternating object presentation task) and visual short-term memory (dishabituation to a novel object on a change preference task).

RESULTS

Latency to shift attention was negatively associated with Bayley Cognitive Scale raw scores, even when controlling for the effects of chronological age, r (33) = -.41, P = .02. In addition, prematurity status was associated with latency to shift attention.

CONCLUSIONS

Early attention shifting may be an important factor that facilitates overall cognitive skill acquisition in infants with Down syndrome, and premature birth may be a risk factor for difficulties on this dimension.

Sit Still and Pay Attention! Trunk Movement and Attentional Resources in Infants with Typical and Delayed Development

AIMS

(1) examine infant movement during an early posture (sitting) utilizing a novel video assessment technique; and (2) document the differences between infants with typical development (TD), premature infants with motor delay, and infants with cerebral palsy (CP) during focused and nonfocused attention (NFA).

METHODS

Infants were tested when they began to sit independently. We utilized Eulerian Video Magnification (EVM) to accentuate small trunk and pelvic movements for visual coding from video taken during a natural play task with and without focused attention (FA).

RESULTS

Trunk/pelvic movement varied as a function of both motor skill and attention. Infants with TD and CP made fewer trunk movements during periods of FA than NFA. Preterm infants exhibited more trunk/pelvic movement than the other groups and their movement did not differ based on attention type.

CONCLUSIONS

The EVM technique allowed for replicable coding of real-time "hidden" motor adjustments from video. The capacity to minimize extraneous movements in infants, or "sitting still" may allow greater attention to the task at hand, similar to older children and adults. Premature infants' excessive trunk/pelvic movement that did not adapt to task requirements could, in the long term, impact tasks requiring attentional resources.

Rapid Infant Prefrontal Cortex Development and Sensitivity to Early Environmental Experience

Over the last fifteen years, the emerging field of developmental cognitive neuroscience has described the relatively late development of prefrontal cortex in children and the relation between gradual structural changes and children's protracted development of prefrontal-dependent skills. Widespread recognition by the broader scientific community of the extended development of prefrontal cortex has led to the overwhelming perception of prefrontal cortex as a "late developing" region of the brain. However, despite its supposedly protracted development, multiple lines of research have converged to suggest that prefrontal cortex development may be particularly susceptible to individual differences in children's early environments. Recent studies demonstrate that the impacts of early adverse environments on prefrontal cortex are present very early in development: within the first year of life. This review provides a comprehensive overview of new neuroimaging evidence demonstrating that prefrontal cortex should be characterized as a "rapidly developing" region of the brain, discusses the converging impacts of early adversity on prefrontal circuits, and presents potential mechanisms via which adverse environments shape both concurrent and long-term measures of prefrontal cortex development. Given that environmentally-induced disparities are present in prefrontal cortex development within the first year of life, translational work in intervention and/or prevention science should focus on intervening early in development to take advantages of this early period of rapid prefrontal development and heightened plasticity.

Training of parental scaffolding in high-socio-economic status families: How do parents of full- and preterm-born toddlers benefit?

BACKGROUND

Preterm children have an increased risk regarding self-regulation development. Given the strong link between parenting behaviour (i.e., scaffolding and sensitivity) and children's self-regulation, parental training presents a promising way to counteract the negative consequences of preterm birth.

AIMS

We explored the effectiveness of parental training by comparing a basic scaffolding training and a combined scaffolding/sensitivity training to an active treatment-control group (stress management). Basic and combined treatments should increase parents' domain-specific self-efficacy (DSSE) and beliefs on parental co-regulation and the promotion of learning (BCL) more than the control treatment should. No such differences were expected for parents' domain-general self-efficacy (DGSE). We examined whether parents of preterm and full-term children benefitted equally from training conditions.

SAMPLE(S)

A total of 87 parents of full-term and 35 parents of preterm toddlers (24-36 months of age, corrected for prematurity) participated.

METHODS

Based on a quasi-experimental pre-test-post-test follow-up design, parents were randomly assigned to treatments. A multimethod approach was applied, including self-report, parent-child interactions, and standardized behavioural tasks. The presented study is limited to questionnaire data on parents' DGSE, DSSE, and BCL.

RESULTS

An overall increase resulted from pre- to post-test and/or follow-up. Parents' BCL changed significantly stronger in the combined training than in the control group. Parents of preterm and full-term children benefitted equally from basic and combined training.

CONCLUSIONS

The combined training enhanced BCL among parents of full-term and preterm children the most. If such training also yields improvement on the behavioural level, this finding will advance preterm aftercare.

The predictive value of early oral motor assessments for neurodevelopmental outcomes of moderately and late preterm infants

Oral motor assessment is used to identify abnormal sucking patterns which may reflect neurodevelopmental problems in preterm infants, but few studies have focused on moderately and late preterm infants. We enrolled 118 moderately and late preterm infants (mean gestational age, 35.04 weeks; mean birth weight, 2347.59 g) and analyzed the relationship between the Neonatal Oral-Motor Assessment Scale scores of these infants and the Chinese revision of Bayley Scales of Infant Development outcomes at 6 months corrected age. And the infants with abnormal sucking pattern had significantly lower Mental Development Index and Psychomotor Development Index and showed a higher rate of below average scores than control group (P = .003, P = .029, P = .022). The incoordination of suck-swallow-respiration was a risk factor for adverse neurodevelopment (RR = 3.67, 95% CI: 1.42-9.45). These indicate that abnormal sucking patterns in moderately and late preterm infants might provide some predictive value for short-term neurodevelopmental outcomes, but the clinical predictive value for developmental delay need to be determined in a longer term follow-up. This finding may offer a basis for early intervention.

Social Cognition in Children Born Preterm: A Perspective on Future Research Directions

Preterm birth is a major risk factor for children’s development. It affects children’s cognitive and intellectual development and is related to impairments in IQ, executive functions, and well-being, with these problems persisting into adulthood. While preterm children’s intellectual and cognitive development has been studied in detail, their social development and social-cognitive competencies have received less attention. Namely, preterm children show problems in interactions with others. These interaction problems are present in relationships with parents, teachers, and peers. Parents’ behavior has been identified as a possible mediator of children’s social behavior. Maternal sensitivity and responsiveness as well as absence of mental disorders foster children’s social development. In this article, we will report on the social side of impairments that preterm children face. The review of the literature revealed that preterm infants’ joint attention abilities are impaired: They are less likely to initiate joint attention with others and to respond to others’ efforts to engage in joint attention. These deficits in joint attention might contribute to later impairments in social cognition, which in turn might affect social interaction skills. Based on these three domains (i.e., problems in social interaction, parental behavior, and impairments in joint attention), we suggest that preterm children’s social cognitive abilities should be investigated more intensively.

Longitudinal patterns of early development in Canadian late preterm infants: A prospective cohort study

This prospective, longitudinal cohort study examined longitudinal patterns of early development in Canadian children born late preterm. A convenience sample of 82 mothers and their healthy, singleton, late preterm children participated. Mothers completed the Ages and Stages Questionnaires at 4, 8, and 18 months corrected age. Concerns were most commonly reported in the communication and gross motor domains, especially early in development. The proportion of children scoring below the referral cut-off in at least one domain at 4, 8, and 18 months was, respectively, 25.6, 25.6, and 14.6%. Only two children (2.4%) scored below referral cut-off in at least one domain at all three time points. At ages four and eight months, the late preterm sample had significantly lower communication and gross motor scores than the Ages and Stages Questionnaires normative sample. At age four months, there was also a significant difference on the fine motor domain. There were no significant differences at age 18 months. Healthy late preterm children appear to catch up to population norms by age 18 months corrected age. Longer term studies are needed to further clarify early indicators of delay in late preterm children and identity those who require close developmental monitoring.

Developmental Outcomes of Late Preterm Infants From Infancy to Kindergarten

OBJECTIVE

To compare developmental outcomes of late preterm infants (34-36 weeks' gestation) with infants born at early term (37-38 weeks' gestation) and term (39-41 weeks' gestation), from infancy through kindergarten.

METHODS

Sample included 1000 late preterm, 1800 early term, and 3200 term infants ascertained from the Early Childhood Longitudinal Study, Birth Cohort. Direct assessments of development were performed at 9 and 24 months by using the Bayley Short Form-Research Edition T-scores and at preschool and kindergarten using the Early Childhood Longitudinal Study, Birth Cohort reading and mathematics θ scores. Maternal and infant characteristics were obtained from birth certificate data and parent questionnaires. After controlling for covariates, we compared mean developmental outcomes between late preterm and full-term groups in serial cross-sectional analyses at each timepoint using multilinear regression, with pairwise comparisons testing for group differences by gestational age categories.

RESULTS

With covariates controlled at all timepoints, at 9 months late preterm infants demonstrated less optimal developmental outcomes (T = 47.31) compared with infants born early term (T = 49.12) and term (T = 50.09) (P < .0001). This association was not seen at 24 months, (P = .66) but reemerged at preschool. Late preterm infants demonstrated less optimal scores in preschool reading (P = .0006), preschool mathematics (P = .0014), and kindergarten reading (P = .0007) compared with infants born at term gestation.

CONCLUSIONS

Although late preterm infants demonstrate comparable developmental outcomes to full-term infants (early term and full-term gestation) at 24 months, they demonstrate less optimal reading outcomes at preschool and kindergarten timepoints. Ongoing developmental surveillance for late preterm infants is warranted into preschool and kindergarten.

Brain Volumes at Term-Equivalent Age Are Associated with 2-Year Neurodevelopment in Moderate and Late Preterm Children

OBJECTIVE

To explore the association between brain maturation, injury, and volumes at term-equivalent age with 2-year development in moderate and late preterm children.

STUDY DESIGN

Moderate and late preterm infants were recruited at birth and assessed at age 2 years using the Bayley Scales of Infant and Toddler Development, Third Edition. Brain magnetic resonance imaging (MRI) was performed at term-equivalent age and qualitatively assessed for brain maturation (myelination of the posterior limb of the internal capsule and gyral folding) and injury. Brain volumes were measured using advanced segmentation techniques. The associations between brain MRI measures with developmental outcomes were explored using linear regression analyses.

RESULTS

A total of 197 children underwent MRI and assessed using the Bayley Scales of Infant and Toddler Development, Third Edition. Larger total brain tissue volumes were associated with higher cognitive and language scores (adjusted coefficients per 10% increase in brain size; 95% CI of 3.2 [0.4, 5.6] and 5.6 [2.4, 8.8], respectively). Similar relationships were documented for white matter volumes with cognitive and language scores, multiple cerebral structures with language scores, and cerebellar volumes with motor scores. Larger cerebellar volumes were independently associated with better language and motor scores, after adjustment for other perinatal factors. There was little evidence of relationships between myelination of the posterior limb of the internal capsule, gyral folding, or injury with 2-year development.

CONCLUSIONS

Larger total brain tissue, white matter, and cerebellar volumes at term-equivalent age are associated with better neurodevelopment in moderate and late preterm children. Brain volumes may be an important marker for neurodevelopmental deficits described in moderate and late preterm children.

Poorer divided attention in children born very preterm can be explained by difficulty with each component task, not the executive requirement to dual-task

Children born very preterm (VP, ≤ 32 weeks) exhibit poor performance on tasks of executive functioning. However, it is largely unknown whether this reflects the cumulative impact of non-executive deficits or a separable impairment in executive-level abilities. A dual-task paradigm was used in the current study to differentiate the executive processes involved in performing two simple attention tasks simultaneously. The executive-level contribution to performance was indexed by the within-subject cost incurred to single-task performance under dual-task conditions, termed dual-task cost. The participants included 77 VP children (mean age: 7.17 years) and 74 peer controls (mean age: 7.16 years) who completed Sky Search (selective attention), Score (sustained attention) and Sky Search DT (divided attention) from the Test of Everyday Attention for Children. The divided-attention task requires the simultaneous performance of the selective- and sustained-attention tasks. The VP group exhibited poorer performance on the selective- and divided-attention tasks, and showed a strong trend toward poorer performance on the sustained-attention task. However, there were no significant group differences in dual-task cost. These results suggest a cumulative impact of vulnerable lower-level cognitive processes on dual-tasking or divided attention in VP children, and fail to support the hypothesis that VP children show a separable impairment in executive-level abilities.