Very preterm (VPT) infants are at-risk for altered growth, slower speed of processing (SOP), and hypertension. This study assesses the relationship between postnatal body composition (BC), ...neurodevelopment (indexed by SOP), and blood pressure (BP) in VPT infants.
Thirty-four VPT infants underwent weekly measurements and BC testing until discharge and post-discharge at 4 mos CGA and 4 yrs. At post-discharge visits, SOP was assessed using visual evoked potentials and the NIH Toolbox; BP was also measured.
In-hospital rate of weight, length and fat-free mass (FFM) gains were associated with faster SOP at 4 yrs. Higher rate of gains in weight and FFM from discharge to 4 mos CGA were associated with faster SOP at 4 mos CGA, while higher fat mass (FM) gains during the same time were positively associated with BP at 4 yrs. BC at 4 yrs nor gains beyond 4 mos CGA were associated with outcomes.
In VPT infants, early FFM gains are associated with faster SOP, whereas post-discharge FM gains are associated with higher BPs at 4 yrs. This shows birth to 4 mos CGA is a sensitive period for growth and its relation to neurodevelopmental and metabolic outcomes. Close monitoring and early nutritional adjustments to optimize quality of gains may improve outcomes.
Despite advances in care, preterm infants exhibit disproportionate growth and neurodevelopmental delay attributable to both nutritional and nonnutritional factors. These infants have prolonged linear ...stunting and decreased fat-free mass compared with their term counterparts. These 2 metrics index organ growth and development (including the brain) and protein accretion. Protein, along with carbohydrates, fats, and zinc, plays key roles in brain development, and deficiencies can lead to linear growth failure, abnormalities in the growth hormone axis, and developmental delay. Optimization of nutrition, including protein intake, decreasing inflammatory episodes, and enhancing the growth hormone axis will likely improve long-term outcomes.
Preterm infants are at risk for long-term neurodevelopmental impairment as a function of postnatal nutritional status. Despite adequate neonatal weight gain, preterm infants have altered body ...composition, with lower fat-free mass (FFM) and higher adiposity at term corrected gestational age (CGA) than their term counterparts. The relationship between postnatal body composition and speed of brain processing in preterm infants is unknown.
Anthropometric measurements and body composition testing via air displacement plethysmography were performed on 16 appropriate-for-gestational age (GA) preterm (mean GA: 30.4 ± 2.8 wk) infants at term and 4 mo CGA. Infant visual pathway development was assessed at 4 mo CGA using pattern-reversal visual evoked potential (VEP); P100 (positive peak) latency was used to index neuronal speed of processing.
Increased FFM at discharge (P = 0.02) and 4 mo CGA (P = 0.006) was associated with shorter latencies to the P100 peak. P100 latency was not related to total body weight, fat mass, or body fat percentage.
FFM reflects protein accretion and indexes growth of organs, including the brain. The association of shorter VEP latency (i.e., faster neuronal processing) with higher FFM (i.e., better protein status) may be attributed to the positive effects of protein status on neuronal growth and differentiation.
Hypoxic ischemic encephalopathy (HIE) remains a significant cause of disability despite treatment with therapeutic hypothermia (TH). Many survive with more subtle deficits that affect daily ...functioning and school performance. We have previously shown an early indication of hippocampal changes in infants with HIE despite TH. The aim of this study was to evaluate the hippocampal volume via MRI and memory function at 5 years of age. A cohort of children followed from birth returned for a 5-year follow-up (
= 10 HIE treated with TH,
= 8 healthy controls). The children underwent brain MRI and neurodevelopmental testing to assess their brain volume, general development, and memory function. Children with HIE had smaller hippocampal volumes than the controls despite no differences in the total brain volume (
= 0.02). Children with HIE generally scored within the average range on developmental testing. Though there was no difference in the memory scores between these groups, there was a positive within-group correlation between the hippocampal volume and memory scores in children with HIE (sentence recall r = 0.66,
= 0.038). There was no relationship between newborn memory function and 5-year hippocampal size. Children with HIE treated with TH experienced significant and lasting changes to the hippocampus despite improvements in survival and severe disability. Future studies should target diminishing injury to the hippocampus to improve overall outcomes.
Survivors of neonatal encephalopathy (NE) are at risk for impaired cognition. The objective of this study was to assess speed of processing (SOP) and memory in infants with moderate NE.
Sample ...consisted of 17 infants with NE and 23 healthy controls. Visual-evoked potentials (VEP) were assessed at 8 months to assess SOP. Memory was assessed at 12 months using elicited imitation (EI). Memory and SOP had previously been assessed in this cohort in the newborn period.
Infants with NE had similar SOP and EI performance as controls. Newborn SOP correlated with 8-month SOP in infants with NE, however, neonatal ERP memory measures were not correlated with EI performance at 12 months.
Infants with moderate NE treated with TH show preserved memory and SOP through 12 months. Early behavioral and electrophysiologic assessments of memory and SOP provide insight into developing cognitive functions in this risk group.
Neonatal encephalopathy (NE) carries high risk for neurodevelopmental impairments. Therapeutic hypothermia (TH) reduces this risk, particularly for moderate encephalopathy (ME). Nevertheless, these ...infants often have subtle functional deficits, including abnormal memory function. Detection of deficits at the earliest possible time-point would allow for intervention during a period of maximal brain plasticity.
Recognition memory function in 22 infants with NE treated with TH was compared to 23 healthy controls using event-related potentials (ERPs) at 2 wk of age. ERPs were recorded to mother's voice alternating with a stranger's voice to assess attentional responses (P2), novelty detection (slow wave), and discrimination between familiar and novel (difference wave). Development was tested at 12 mo using the Bayley Scales of Infant Development, Third Edition (BSID-III).
The NE group showed similar ERP components and BSID-III scores to controls. However, infants with NE showed discrimination at midline leads (P = 0.01), whereas controls showed discrimination in the left hemisphere (P = 0.05). Normal MRI (P = 0.05) and seizure-free electroencephalogram (EEG) (P = 0.04) correlated positively with outcomes.
Infants with NE have preserved recognition memory function after TH. The spatially different recognition memory processing after early brain injury may represent compensatory changes in the brain circuitry and reflect a benefit of TH.
Early aggressive nutrition is associated with improved neurodevelopmental outcomes, and is increasingly becoming the standard of care for preterm infants. Additionally, more rapid growth while in the ...NICU has been linked to lower risk of abnormal motor and cognitive development. However, as increasing reports of the metabolic consequences of rapid growth in other populations (i.e. appropriately grown and growth-restricted term infants) become available, we must consider the possibility that these negative long-term health outcomes may also affect preterm infants. This becomes especially concerning as studies revealing the prevalence of disproportionate growth and increased adiposity upon discharge from the NICU are published. This article will review the available literature on the impact of nutrition, illness and growth during several different epochs (i.e. first weeks of life, later inpatient weeks and post-discharge) on
both
neurodevelopmental and metabolic outcomes in preterm infants.
ABSTRACT
Accretion of stars on massive black holes (MBHs) can feed MBHs and generate tidal disruption events (TDEs). We introduce a new physically motivated model to self-consistently treat TDEs in ...cosmological simulations, and apply it to the assembly of a galaxy with final mass $3\times 10^{10}\, \mathrm{M}_{\odot }$ at z = 6. This galaxy exhibits a TDE rate of $\sim 10^{-5}\, \mathrm{yr}^{-1}$, consistent with local observations but already in place when the Universe was one billion year old. A fraction of the disrupted stars participate in the growth of MBHs, dominating it until the MBH reaches mass $\sim 5 \times 10^5 \, \mathrm{M}_{\odot }$, but their contribution then becomes negligible compared to gas. TDEs could be a viable mechanism to grow light MBH seeds, but fewer TDEs are expected when the MBH becomes sufficiently massive to reach the luminosity of, and be detected as, an active galactic nucleus. Galaxy mergers bring multiple MBHs in the galaxy, resulting in an enhancement of the global TDE rate in the galaxy by ∼1 order of magnitude during $100\, \mathrm{Myr}$ around mergers. This enhancement is not on the central MBH, but caused by the presence of MBHs in the infalling galaxies. This is the first self-consistent study of TDEs in a cosmological environment and highlights that accretion of stars and TDEs are a natural process occurring in a Milky Way-mass galaxy at early cosmic times.
How online affinity networks expand learning and opportunity for young people
Boyband One Direction fanfiction writers, gamers who solve math problems together, Harry Potter fans who knit for a ...cause. Across subcultures and geographies, young fans have found each other and formed community online, learning from one another along the way. From these and other in-depth case studies of online affinity networks, Affinity Online considers how young people have found new opportunities for expanded learning in the digital age. These cases reveal the shared characteristics and unique cultures and practices of different online affinity networks, and how they support “connected learning”—learning that brings together youth interests, social activity, and accomplishment in civic, academic, and career relevant arenas. Although involvement in online communities is an established fixture of growing up in the networked age, participation in these spaces show how young people are actively taking up new media for their own engaged learning and social development.
While providing a wealth of positive examples for how the online world provides new opportunities for learning, the book also examines the ways in which these communities still reproduce inequalities based on gender, race, and socioeconomic status. The book concludes with a set of concrete suggestions for how the positive learning opportunities offered by online communities could be made available to more young people, at school and at home. Affinity Online explores how online practices and networks bridge the divide between in-school and out-of-school learning, finding that online affinity networks are creating new spaces of opportunity for realizing the ideals of connected learning.
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