Profiles of neurobehavior and their associations with brain abnormalities on MRI in infants born preterm

Evidence for neurobehavioral risk phenotypes at birth

Observations of newborn behavior provide clinicians and researchers with a first description of the neurobehavioral organization of the newborn that is largely independent of the postnatal environment. The Neonatal Network Neurobehavioral Scale (NNNS) was developed in 2004 to evaluate how prenatal exposure to substances such as cocaine is related to neurobehavioral outcomes. There are now 156 empirical articles published using the NNNS, which we review and summarize. Z-scores from published studies using the NNNS were compiled and aggregated supporting the replicability of three newborn neurobehavioral phenotypes: one typical and two that are predictive of later cognitive and behavioral delay; hyper- and hypo-dysregulated newborns. These phenotypes emerged from independent samples and research groups and were identified in a variety of populations, including infants with prenatal substance exposure, preterm infants, and healthy term infants. Our findings show that newborn neurobehavior can be measured in a reliable and valid manner and that certain behavioral phenotypes, identifiable at birth, can predict neurodevelopmental challenges. These findings have important clinical utility. Intervening early with infants exhibiting these risk phenotypes may prevent later neurodevelopmental delay. IMPACT: We reviewed all empirical studies published using the Neonatal Network Neurobehavioral Scale and found evidence for two replicable stress phenotypes that predict later behavioral outcomes. This study highlights the utility of the Neonatal Network Neurobehavioral Scale for early identification of newborn neurodevelopmental risk phenotypes. Early identification of neurodevelopmental risk, when neuroplasticity is high, may ultimately reduce the burden of subsequent neurobehavioral problems through early intervention.

Bronchopulmonary dysplasia and neurobehavioural outcomes at birth and 2 years in infants born before 30 weeks

OBJECTIVE

To identify neurobehavioural risks in preterm infants with bronchopulmonary dysplasia (BPD) prior to hospital discharge.

DESIGN AND PATIENTS

Longitudinal study of 676 newborns born before 30 weeks of gestation.

SETTING

Nine university NICUs affiliated with six universities. All were Vermont Oxford Network (VON) participants.

PATIENTS AND INTERVENTIONS

Infants were enrolled in the Neonatal Neurobehavior and Outcomes in Very Preterm Infants Study from April 2014 to June 2016. Prospective medical record reviews, VON definitions and criteria, and maternal interviews were used to collect maternal and neonatal medical variables and socioenvironmental data.

MAIN OUTCOME MEASURES

NICU Network Neurobehavioral Scale (NNNS) at the time of hospital discharge; Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) and Gross Motor Function Classification System at 2 years' corrected age.

RESULTS

Infants with moderate/severe BPD were less attentive (Wald χ2 9.68, p=0.008), more lethargic (Wald χ2 9.91, p=0.007), with increased non-optimal reflexes (Wald χ2 7.37, p=0.025). Infants with moderate/severe BPD were more likely to have Bayley-III language and motor scores <85 (adjusted OR (aOR) 1.74, 95% CI 1.06 to 2.85, and aOR 2.06, 95% CI 1.10 to 3.85). Infants with both moderate/severe and mild BPD were more likely to have a cerebral palsy diagnosis (aOR 2.96, 95% CI 1.34 to 6.54, and aOR 2.81, 95% CI 1.32 to 5.99).

CONCLUSIONS

BPD severity presents risks for poor neurodevelopment at NICU discharge and at age 2 years. Early identification of poorly regulated behaviour can provide critical information for early preventive and targeted interventions with potential to improve long-term outcomes.

Neonatal Intensive Care Unit Network Neurobehavioral Scale Profiles in Full-Term Infants: Associations with Maternal Adversity, Medical Risk, and Neonatal Outcomes

OBJECTIVES

To examine healthy, full-term neonatal behavior using the Neonatal Intensive Care Unit Network Neurobehavioral Scale (NNNS) in relation to measures of maternal adversity, maternal medical risk, and infant brain volumes.

STUDY DESIGN

This was a prospective, longitudinal, observational cohort study of pregnant mothers followed from the first trimester and their healthy, full-term infants. Infants underwent an NNNS assessment and high-quality magnetic resonance imaging 2-5 weeks after birth. A latent profile analysis of NNNS scores categorized infants into neurobehavioral profiles. Univariate and multivariate analyses compared differences in maternal factors (social advantage, psychosocial stress, and medical risk) and neonatal characteristics between profiles.

RESULTS

The latent profile analysis of NNNS summary scales of 296 infants generated 3 profiles: regulated (46.6%), hypotonic (16.6%), and fussy (36.8%). Infants with a hypotonic profile were more likely to be male (χ2 = 8.601; P = .014). Fussy infants had smaller head circumferences (F = 3.871; P = .022) and smaller total brain (F = 3.522; P = .031) and cerebral white matter (F = 3.986; P = .020) volumes compared with infants with a hypotonic profile. There were no differences between profiles in prenatal maternal health, social advantage, or psychosocial stress.

CONCLUSIONS

Three distinct neurobehavioral profiles were identified in healthy, full-term infants with hypotonic and fussy neurobehavioral features related to neonatal brain volumes and head circumference, but not prenatal exposure to socioeconomic or psychosocial adversity. Follow-up beyond the neonatal period will determine if identified profiles at birth are associated with subsequent clinical or developmental outcomes.