Developmental assessment of preterm infants: Chronological or corrected age?

The modulating effect of gestational age on attentional disengagement in toddlers

Gestational Age (GA) at birth plays a crucial role in identifying potential vulnerabilities to long-term difficulties in cognitive and behavioral development. The present study aims to explore the influence of gestational age on the efficiency of early visual attention orienting, as a potential marker for the development of specific high-level socio-cognitive skills. We administered the Gap-Overlap task to measure the attentional orienting and disengagement performance of 16-month-olds born between the 34th and 41st weeks of gestation. Our findings indicate that GA might be a significant predictor of attentional disengagement performance, with lower GAs associated with slower orienting of visual attention in the gap condition. Additionally, we discuss a possible influence of endogenous attention control on disengagement accuracy at this age, particularly among full-term infants. Overall, the findings highlight the role of GA as a key factor in evaluating early visual attention development, acting as a marker for detecting early vulnerabilities.

Sitting Acquisition and Early Communication Development: Are There Associations in Very Preterm Infants at Six Months of Corrected Age?

Background: Research in typically and some atypically developing populations showed associations between early motor and communication development, documenting how postural development can support communicative advancements. However, these relations have scarcely been investigated in the preterm population. Aims: The present study aimed to describe motor (gross and fine motor) and communication (receptive and expressive) skills of very preterm infants at six months of corrected age and their associations, focusing on sitting posture achievement and early vocal production. Methods: Seventy very preterm infants (≤32 weeks) with no major brain injuries were assessed with the BSID-III for gross and fine motor skills, receptive and expressive language skills, and cognitive skills and were categorized as mastering (sitters), partially mastering (emerging sitters), or not mastering (non sitters) unsupported sitting. The proportional duration of sitting postures (caregiver supported, arms supported, and unsupported) in an observative section was coded with the Interact software (version 20.8.3.0). Frequency per minute of vocal utterances (vocalizations, babbling, and total) during a parent-infant play interaction was coded with the CHILDES software v11. Results: Correlational analyses showed significant positive associations between motor composite score and language scores (composite and expressive scaled) and between gross motor and expressive language scaled scores but a negative association between arms supported sitting duration and vocal utterances. In addition, ANCOVAs showed that sitters had significantly higher BSID-III expressive language scaled scores and vocal utterances than non sitters and emerging sitters. Conclusions: These findings brought new evidence linking early motor and vocal development in very preterm infants, emphasizing the importance of using observational tools alongside standardized ones to identify developmental delays and plan tailored intervention programmes.

Growth Trajectories of Joint Attention and Play as Predictors for Language in Young Children at Elevated Likelihood for Autism

This longitudinal study investigated the predictive value of initial level and growth rate of joint attention and play from 10 to 24 months for language abilities of 24-month-old toddlers at elevated likelihood (EL) for autism. (Semi-)structured assessments were used to measure all variables at different timepoints prospectively in younger siblings of children with autism (siblings, n = 48) and children born before 30 gestational weeks (preterms, n = 49). A positive association was found between initial level of play at 10 months and expressive language at 24 months in siblings, but not in preterms. We did not find an association between initial level of play and receptive language. Growth rate of play and initial level and growth rate of joint attention were not related to language abilities in siblings and preterms. Our results indicate that play and expressive language are interrelated, and early play behaviour may contribute to later language. As this association was absent in preterms, they may follow qualitatively different developmental processes. Moreover, future research including different EL-groups is needed to clarify these differential associations. In contrast to previous studies, no association between early joint attention and later language was found. These inconsistent findings warrant further exploration and highlight the importance of exploring alternative aspects of early development, for instance non-social factors, to expand our understanding of language acquisition.

[Neurodevelopmental catch-up status and correction termination age in preterm infants of different gestational ages]

OBJECTIVES

To investigate the status of neurodevelopmental catch-up and suitable correction termination age in preterm infants of different gestational ages.

METHODS

A total of 918 preterm infants without significant high-risk factors who attended the outpatient service of the Second Affiliated Hospital of Army Medical University from January 1, 2018 to March 1, 2023 were included. The data on developmental quotient (DQ) in Gesell Developmental Schedule (GDS) were collected, while 6 684 full-term infants were included as controls. According to the gestational age, the infants were divided into preterm groups (early preterm, moderate preterm, and late preterm births) and a full-term group, and these groups were compared in terms of DQ of each functional area and its changing trend with 48 months of chronological age.

RESULTS

The DQ values of all functional areas showed a catch-up trend from 6 months to 48 months of chronological age in each preterm group (P<0.05). There were no significant differences in the DQ values of all functional areas between the late preterm and full-term groups at the chronological age of 36 months (P>0.05). There were significant differences in the DQ values of most functional areas between the moderately/early preterm groups and the full-term group at the chronological age of 36 months (P<0.05), but no significant differences were found in the DQ values of all functions areas at the chronological age of 48 months (P>0.05).

CONCLUSIONS

The correction termination age for neurodevelopment in preterm infants may need to extend beyond 36 months, and the smaller the gestational age, the longer the time required for correction.

The potential and translational application of infant genetic research

In the current genomic revolution, the infancy life stage is the most neglected. Although clinical genetics recognizes the value of early identification in infancy of rare genetic causes of disorders and delay, common genetic variation is almost completely ignored in research on infant behavioral and neurodevelopmental traits. In this Perspective, we argue for a much-needed surge in research on common genetic variation influencing infant neurodevelopment and behavior, findings that would be relevant for all children. We now see convincing evidence from different research designs to suggest that developmental milestones, skills and behaviors of infants are heritable and thus are suitable candidates for gene-discovery research. We highlight the resources available to the field, including genotyped infant cohorts, and we outline, with recommendations, special considerations needed for infant data. Therefore, infant genetic research has the potential to impact basic science and to affect educational policy, public health and clinical practice.

Home Musical Activities Boost Premature Infants' Language Development

Infants born prematurely are considered at risk for language development delay and impairments. Using online parental reports, the present study investigated the influence of early musical experience in the home environment (Music@Home Infant Questionnaire) on language development (MacArthur-Bates Communicative Development Inventory) while controlling for general enrichment at home (Stim-Q Cognitive Home Environment Questionnaire) and perinatal post-traumatic stress disorder (Perinatal PTSD Questionnaire). Caregivers of 117 infants between 8 and 18 months of age (corrected age) without reported developmental difficulties completed an online survey. Results revealed that the musical home environment significantly predicted outcomes in reported infants' receptive vocabulary and gestural communication, independently from infants' corrected age and general enrichment of home activities. These findings constitute the first evidence that an enriched musical experience can enhance the development of early communication skills in a population at risk for language delays, namely infants born prematurely, opening the path for future intervention research in home and/or early childcare settings. Given that the majority of participants in this study were highly educated and from socioeconomically stable backgrounds, considerations regarding the generalizability of these results are discussed.

Machine learning predictive models for grading bronchopulmonary dysplasia: umbilical cord blood IL-6 as a biomarker

Objectives

This study aimed to analyze the predictive value of umbilical cord blood Interleukin-6 (UCB IL-6) for the severity-graded BPD and to establish machine learning (ML) predictive models in a Chinese population based on the 2019 NRN evidence-based guidelines.

Methods

In this retrospective analysis, we included infants born with gestational age <32 weeks, who underwent UCB IL-6 testing within 24 h of admission to our NICU between 2020 and 2022. We collected their medical information encompassing the maternal, perinatal, and early neonatal phases. Furthermore, we classified the grade of BPD according to the 2019 NRN evidence-based guidelines. The correlation between UCB IL-6 and the grades of BPD was analyzed. Univariate analysis and ordinal logistic regression were employed to identify risk factors, followed by the development of ML predictive models based on XGBoost, CatBoost, LightGBM, and Random Forest. The AUROC was used to evaluate the diagnostic value of each model. Besides, we generated feature importance distribution plots based on SHAP values to emphasize the significance of UCB IL-6 in the models.

Results

The study ultimately enrolled 414 preterm infants, with No BPD group (n = 309), Grade 1 BPD group (n = 73), and Grade 2-3 BPD group (n = 32). The levels of UCB IL-6 increased with the grades of BPD. UCB IL-6 demonstrated clinical significance in predicting various grades of BPD, particularly in distinguishing Grade 2-3 BPD patients, with an AUROC of 0.815 (95% CI: 0.753-0.877). All four ML models, XGBoost, CatBoost, LightGBM, and Random Forest, exhibited Micro-average AUROC values of 0.841, 0.870, 0.851, and 0.878, respectively. Notably, UCB IL-6 consistently appeared as the most prominent feature across the feature importance distribution plots in all four models.

Conclusion

UCB IL-6 significantly contributes to predicting severity-graded BPD, especially in grade 2-3 BPD. Through the development of four ML predictive models, we highlighted UCB IL-6's importance.

Neurodevelopmental outcome of low-risk moderate to late preterm infants at 18 months

Background

Of the 15 million preterm births that occur worldwide each year, approximately 80% occur between 32 and 36 + 6 weeks gestational age (GA) and are defined as moderate to late preterm (MLP) infants. This percentage substantiates a need for a better understanding of the neurodevelopmental outcome of this group.

Aim

To describe neurodevelopmental outcome at 18 months in a cohort of healthy low-risk MLP infants admitted to the neonatal unit at birth and to compare the neurodevelopmental outcome to that of a healthy term-born infant group.

Study design and method

This single-centre observational study compared the neurodevelopmental outcome of healthy MLP infants to a group of healthy term control (TC) infants recruited during the same period using the Griffith's III assessment at 18 months.

Results

Seventy-five MLP infants and 92 TC infants were included. MLP infants scored significantly lower in the subscales: Eye-hand coordination (C), Personal, Social and Emotional Development (D), Gross Motor Development (E) and General Developmental (GD) (p < 0.001 for each) and Foundations of Learning (A), (p = 0.004) in comparison to the TC infant group with Cohen's d effect sizes ranging from 0.460 to 0.665. There was no statistically significant difference in mean scores achieved in subscale B: Language and Communication between groups (p = 0.107).

Conclusion

MLP infants are at risk of suboptimal neurodevelopmental outcomes. Greater surveillance of the neurodevelopmental trajectory of this group of at-risk preterm infants is required.

Cord blood adiponectin and leptin concentrations in monochorionic twins with selective intrauterine growth restriction and their associations with childhood growth trajectories

BACKGROUND

Being born with intrauterine growth restriction (IUGR) was associated with subsequent health issues later in life. However, the underlying role of adipokines in IUGR is unknown.

OBJECTIVES

To measure the adiponectin and leptin concentrations in the cord blood of monochorionic (MC) twins with selective IUGR (sIUGR) and evaluate their associations with childhood growth trajectories.

METHODS

Cord blood samples were collected from 22 pairs of MC twins with sIUGR and 20 pairs of normal MC twins. Adiponectin and leptin concentrations in cord blood were determined by ELISA. Data regarding perinatal outcomes and infantile growth trajectories from birth to 24 months were obtained.

RESULTS

Only cord blood adiponectin concentrations were associated with IUGR (β -1.51, 95% CI -2.45, -0.57, p = 0.002), and cord blood leptin concentrations were significantly lower in sIUGR twins compared to normal twins (2.8 ± 1.6 vs. 6.4 ± 3.0, p < 0.001). Adiponectin concentrations were negatively associated with height increments from birth to 6 months (β -0.28, 95% CI -0.51, -0.06, p = 0.015). Leptin concentrations were negatively associated with weight at 6 and 24 months (β -0.12 95% CI -0.22, -0.02, p = 0.002; β -0.18 95% CI -0.33, -0.03, p = 0.019) and weight and height increments from birth to 6 months (β -0.17 95% CI -0.29, -0.06, p = 0.020; β -0.40 95% CI -0.81, -0.01, p = 0.037).

CONCLUSION

Cord blood adiponectin concentrations were negatively associated with IUGR but did not predict childhood growth. Cord blood leptin concentrations were inversely associated with weight and height increments in the first 6 months.

Effects of Correcting for Prematurity on Executive Function Scores of Children Born Very Preterm at School Age

OBJECTIVE

To investigate whether correction for prematurity affects executive function scores in school-aged children born very preterm.

STUDY DESIGN

Executive functions were assessed with standardized neuropsychological tests in 142 children born very preterm (born at ≤32 weeks of gestational age or with a birth weight of ≤1500 g) and 391 control children, aged 7-13 years. Four-month age bands were established from the data of control children. Differences between uncorrected and corrected scores were compared against zero difference and between very preterm children born before and after 28 weeks of gestation. Regression models were used to compare the uncorrected and corrected scores of children born very preterm with control children.

RESULTS

For all executive functions, significant, larger-than-zero differences between uncorrected and corrected scores were apparent in children born very preterm. Mean differences ranged from 0.04 to 0.18 SDs. Weak evidence was found that the effect of age correction is more pronounced in very preterm children born before 28 weeks of gestation than in those born after 28 weeks. Differences in executive function scores between children born very preterm and control children were attenuated if scores were corrected for prematurity.

CONCLUSIONS

Test scores based on corrected rather than uncorrected age may more accurately determine the developmental stage of very preterm children's executive functions at school age. Potential consequences for clinical and research practice need to be discussed in the future.

Screening for Autism Spectrum Disorder in Premature Subjects Hospitalized in a Neonatal Intensive Care Unit

Considering that the average age for diagnosis of autism spectrum disorder (ASD) is 4–5 years, testing screening methods for ASD risk in early infancy is a public health priority. This study aims to identify the risks for development of ASD in children born prematurely and hospitalized in a neonatal intensive care unit (NICU) and explore the association with pre-, peri- and postnatal factors. Methods: The children’s families were contacted by telephone when their child was between 18 and 24 months of age, to apply the Modified Checklist for Autism in Toddlers (M-CHAT). The sample consisted of 40 children (57.5% boys). M-CHAT screening revealed that 50% of the sample showed early signs of ASD. Although the frequency of delayed development was higher in boys, this difference was not statistically significant between the sexes (p = 0.11). Assessment of the association between perinatal conditions and early signs of autism in children hospitalized in an NICU exhibited no correlation between the factors analyzed (birth weight and type of delivery). The findings indicate a high risk of ASD in premature children, demonstrating no associations with gestational and neonatal variables or the hospitalization conditions of the NICUs investigated.

Combined predictors of neurodevelopment in very low birth weight preterm infants

OBJECTIVE

To evaluate the combined prognostic value of neurological examination, head circumference and cranial ultrasound for neurodevelopmental delay (NDD) in very low birth weight (VLBW, <1500 g) preterm infants.

METHODS

Prospective follow-up study. Preterm infants with VLWB were assessed for NDD using the Mullen Scales of Early Learning test at 24 months of corrected age. Abnormal neurological examination (≥2 deviant items of Hammersmith neurological examination), microcephaly and major ultrasound abnormalities, each performed at term age, were evaluated as predictors of NDD in a multivariable Poisson model.

RESULTS

35/132 infants (26.5%) had NDD. In the multivariable analysis, microcephaly (RR, 3.2; 95% CI, 1.6-6.7) and major ultrasound abnormalities (RR, 2.7; 95% CI, 1.3-5.7) were associated to NDD. The combination of the two tests showed the highest positive predictive value (100%; 95% CI, 51%-100%), while the combination of normal neurological examination, no major US findings and normal head size at term showed the highest negative predictive value (89%; 95% CI, 78%-95%). The maximum under receiver operating characteristic curve area was for microcephaly or major ultrasound abnormalities (AUC 0.74 (0.65-0.83)).

CONCLUSION

The combination of head circumference, cranial ultrasound and neurological examination at term age is useful to predict NDD in VLBW preterm infants.

Very early introduction of semisolid foods in preterm infants does not increase food allergies or atopic dermatitis

BACKGROUND

The optimal age for the introduction of solid foods for infants has long been a controversial issue.

OBJECTIVE

To determine whether the early introduction of semisolid foods influences the incidence of food allergy or atopic dermatitis among preterm infants.

METHODS

Retrospective data from 464 preterm infants born in Oulu University Hospital between 2008 and 2012 were analyzed. Age- and sex-matched full-term control children from the general population were identified. The primary outcome of the study was the difference in timing of the introduction of complementary feeding between preterm and full-term infants. The secondary outcomes were the incidences of food allergies and atopic dermatitis by the ages of 1 and 2 years.

RESULTS

Semisolid food was introduced at the median corrected age of 1.4 months for all preterm infants, at 1.9 months for late preterm, at 0.9 months for very preterm, and at 0.1 months for extremely preterm infants. The cumulative incidence, either of food allergies or of atopic dermatitis, did not differ significantly between preterm infants and controls by the ages of 1 and 2 years.

CONCLUSION

The very early introduction of complementary foods into the diet of preterm babies did not increase the incidence of food allergies or atopic dermatitis even among the most preterm infants. This finding supports the hypothesis that the gut-associated lymphoid tissue of preterm infants is ready to encounter food proteins and to begin the maturation process within 3 to 6 months of birth, regardless of gestational age.