Differences in the dynamics of frontal sharp transients in normal and hypoglycemic newborns

The frontal sharp transient in newborns: An endogenous neurobiomarker concomitant to the physiological and critical transitional period around delivery?

The frontal sharp transient (FST) consists of transient electrical activity recorded around the transitional period from the in to ex utero environment. Although its positive predictive value is assumed, nothing is known about its functionality or origin. The objectives were (i) to define its characteristics and (ii) to develop functional hypothesis. The 128-channels high-resolution electroencephalograms of 20 healthy newborns (37.1-41.6 weeks) were studied. The morphological and time-frequency characteristics of 418 FSTs were analyzed. The source localization of the FSTs was obtained using a finite element head model (5 layers and fontanels) and various source localization methods (distributed and dipolar). The characteristics (duration, slopes, and amplitude) and the localization of FSTs were not modulated by the huge developmental neuronal processes that occur during the very last period of gestation. The sources were located beneath the ventral median part of the frontal lobe around the interhemispheric fissure, suggesting that the olfactory bulbs and orbitofrontal cortex, essential in olfaction and the mother-infant attachment relationship, are likely candidates for the generation of FSTs. FSTs may contribute to the implementation of the functionalities of brain structures involved in the higher-order processing necessary for survival ahead of delivery, with a genetic fingerprint.

Nutrition and management of glycemia in neonates with neonatal encephalopathy treated with hypothermia

Adequate nutrition and glycemic homeostasis are increasingly recognized as potentially neuroprotective for the developing brain. In the context of hypoxia-ischemia, evidence is scarce regarding optimal nutritional support and administration route, as well as the short- and long-term consequences of such interventions. In this review, we summarize current knowledge on disturbances of brain metabolism of glucose and substrates by hypoxia-ischemia, and compound effects of these mechanisms on brain injury characterized by specific patterns on EEG and MRI. Risks and benefits of nutrition delivery via parenteral or enteral routes are examined. Nutrition could mitigate adverse neurodevelopmental outcomes, and the impact of nutritional strategies and specific nutritional interventions are reviewed. Limited literature highlights the need for further studies to understand the changes in energy metabolism during and after hypoxic-ischemic injury, to optimize nutritional regimens and glucose management, and to inform the neuroprotective role of nutrition.

Pilot study of EEG in neonates born to mothers with gestational diabetes mellitus

BACKGROUND

The goal was to evaluate whether there was neurodevelopmental deficits in newborns born to mothers with gestational diabetes mellitus (GDM) compared to control newborns born to healthy mothers.

METHODS

Forty-six pregnant women (21 controls and 25 GDM) were recruited. Electroencephalogram (EEG) was recorded in the newborns within 48 h after birth. The EEG signal was quantitatively analyzed using power spectral density (PSD); coherence between hemispheres was calculated in paired channels of frontal, temporal, central and occipital regions.

RESULTS

The left centro-occipital PSD in control newborns was 12% higher than in GDM newborns (p = 0.036) but was not significant after adjustment for gestational age. While coherence was higher in the frontal regions compared to the occipital regions (p < 0.001), there was no difference between the groups for the fronto-temporal, frontal-central, centro-occipital and tempo-occipital regions.

CONCLUSION

Our results support that EEG differences between groups were mainly modified by gestational age and less by GDM status of the mothers. However, there is a need to confirm this result with a higher number of mother-newborns. Quantitative EEG in GDM newborns within 48 h after birth is feasible. This study emphasizes the importance of controlling blood glucose during GDM to protect infant brain development.

Predictive value of sequential electroencephalogram (EEG) in neonates with seizures and its relation to neurological outcome

The aim of this study was to evaluate the relationship of sequential neonatal electroencephalography (EEG) and neurological outcome in neonates with seizures to identify polysomnographic features predictive of outcome. Sequential EEGs recordings of 58 neonates that belonged to 2 historical cohorts of newborns with seizures from the same neonatal intensive care unit and who had follow-up at the Neurodevelopment Clinic of the Hospital São Lucas, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS) in Porto Alegre, Brazil, were analyzed and classified into 4 groups: normal-normal, abnormal-normal, abnormal-abnormal, normal-abnormal. In patients with more than 2 recordings, during the neonatal period, the first EEG was compared with the following more abnormal. A total of 58 pairs of 2 sequential EEGs were analyzed. Considering the first EEG, a statistically significant difference was observed between the relationship of the result of this exam, if it was abnormal, with developmental delay (P = .030) and postnatal death (P = .030). Abnormal background activity was also related to neurodevelopment delay (P = .041). EEG sequences abnormal-abnormal and normal-abnormal significantly correlated to the outcome epilepsy ( P = .015). Abnormal sequential background activity was associated with neurodevelopment delay (P = .006) and epilepsy (P = .041). The burst suppression pattern when present in any EEG correlated with epilepsy (P = .013) and postnatal death (P = .034). Sequential abnormal background patterns in the first and second EEG increased the risk for epilepsy (relative risk [RR] = 1.8; 95% confidence interval [CI] = 1.03-3.0) and neurodevelopment delay (RR = 2.20; 95% CI = 1.3-3.0). Abnormal background activity only in the second electroencephalogram increased the risk for neurodevelopment delay (RR = 2.20; 95% CI = 1.3-3.0). All the neonates (n = 33) with seizures related to probable hypoxic ischemic encephalopathy had abnormalities in the first EEG (P = .030). Postnatal epilepsy was diagnosed in 24 infants (41.4%). Five (20.8%) presented West syndrome, 7 (29.2%) focal symptomatic epilepsy, 6 (25%) generalized symptomatic epilepsy, 2 (8.3%) early myoclonic encephalopathy, 1 (4.2%) early infantile epileptic encephalopathy, and in 3, the epileptic syndrome was undefined (12.5%). All infants (n = 5) with West syndrome had some degree of neurodevelopment delay. In conclusion, our findings suggest that sequential EEG in neonates with seizures has more predictive value to estimate the outcomes of neurodevelopment delay, epilepsy, and postnatal death than a single EEG recording. The abnormal background activity in even 1 EEG of the sequential recordings was more significant to determine neurological outcome than abnormal ictal activity or abnormalities in the organization of sleep state.

Analysis of frontal sharp transients in 32 neonatal polysomnography in healthy fullterm newborns

OBJECTIVE: To identify and quantify frontal sharp transients found in neonatal polysomnography of healthy full term newborns in each stage of the sleep-wake cycle within the first 48 hours of life. METHOD: The EEG from healthy term 32 newborns, legal age of two days and with adequate monitoring during pregnancy. Frontal sharp transients (FST) were quantified, according to synchronous or asynchronous, in each stage of the sleep-wake cycle. The results were compared by Kruskal-Wallis-test. RESULTS: FST were counted individually in each sleep phase, being present during quiet sleep (QS) in all tracings. FST bilateral and synchronous and lateralized FST were more frequent during QS (p<0.05). CONCLUSION: Lateralized FST were found mostly during quiet sleep. FST asynchronous in healthy full term newborns were normal and depended of FST density. FST unilateral appearance should not necessarily be considered abnormal as well.

Glucose metabolism in the late preterm infant

Prematurity and low birth weight are important determinants of neonatal morbidity and mortality. A rising trend of preterm births is caused by an increase in the birth rate of near-term infants. Near-term infants are defined as infants of 34 to 36 6/7 weeks gestation. It is dangerous to assume that the incidence of hypoglycemia in the later preterm infant is similar to the infant born at full term. Although current methods for assessing effects of hypoglycemia are imperfect, the injury to central nervous system depends on the degree of prematurity, presence of intrauterine growth restriction (IUGR), intrauterine compromise, genotype, blood flow, metabolic rate, and availability of other substrates. Therefore, early recognition of glucose metabolic abnormalities pertaining to late preterm infants is essential to provide appropriate and timely interventions in the newborn nursery. Although many of the investigations have targeted full-term infants, premature infants inclusive of the extremely low birth weight infants and the intrauterine growth-restricted infants, adequately powered studies restricted to only the late preterm infants are required and need future consideration.

Neurodevelopment after neonatal hypoglycemia: a systematic review and design of an optimal future study

OBJECTIVE

Our goal was to assess the effect of episodes of neonatal hypoglycemia on subsequent neurodevelopment.

METHODS

We searched Medline and Embase for cohort studies on subsequent neurodevelopment after episodes of hypoglycemia in the first week of life. Reference lists of available studies were reviewed, and content experts were contacted for additional studies. Included studies were selected and appraised for methodologic quality by 2 reviewers. Methodologic quality was assessed according to well-accepted criteria for prognostic studies. Eventually, all studies were given an overall quality score: poor, moderate, or high quality. Studies in the latter 2 categories were considered for quantitative data analysis.

RESULTS

Eighteen eligible studies were identified. The overall methodologic quality of the included studies was considered poor in 16 studies and high in 2 studies. Pooling of results of the 2 high-quality studies was deemed inappropriate because of major clinical and methodologic heterogeneity. None of the studies provided a valid estimate of the effect of neonatal hypoglycemia on neurodevelopment. Building on the strengths and weaknesses of existing studies, we developed a proposal for an "optimal" future study design.

CONCLUSIONS

Recommendations for clinical practice cannot be based on valid scientific evidence in this field. To assess the effect of neonatal hypoglycemia on subsequent neurodevelopment, a well-designed prospective study should be undertaken. We submit a design for a study that may answer the still-open questions.

Developmental characteristics of temporal sharp transients in the EEG of normal preterm and term newborns

OBJECTIVE: To describe developmental characteristics, morphological aspects and incidence of temporal sharp transients (TST) in normal preterm and term newborns at matched conceptional ages (CA). METHOD: Neonatal EEGs from two groups of normal newborns were evaluated in order to identify and characterize TST. Group I (n=40) consisted of newborns from 34 to 40 weeks of gestational age (GA) that were submitted to a single EEG between 24 and 48 hours of life. Group II consisted of 10 preterm newborns with GA between 30-32 weeks, followed with a weekly EEG until they reached term. Morphology of TST was divided in 3 groups (temporal sawtooth, isolated transients or repetitive transients). TST index, density and total number were calculated in each polysomnography and related to sleep stages and CA. Laterality (right/left) was also evaluated. The groups were compared at 34, 36, 38 and 40 weeks of CA. RESULTS: TST index and density decreased with the increase of CA in both groups (p<0.0001). The temporal sawtooth feature was registered in both groups only at 34 weeks. Although rare, repetitive and isolated TST were the most prevalent morphology between 36 - 40 weeks CA. Significant intragroup difference was observed in the comparison of TST density in REM and transitional sleep in GI. Moreover, isolated TST morphology was significant higher in GI at 34 weeks when compared to the others CA. No intragroup differences were observed on GII. No significant differences between the groups were observed considering TST number, index, density, morphology or laterality, at the matched CA. CONCLUSION: TST are normal features of neonatal EEG, as they are registered in normal newborns. Its incidence varies accordingly to morphology and they tend to disappear following the increase of CA. Temporal sawtooth appears more often in preterm newborns. Our results suggest that TST index, density and morphology variability may be a function of CA.

Polysomnography in neonatal seizures

Seizures are one of the most frequent problems in the neonatal period, and are frequently associated with high mortality and morbidity rates. On the other hand, neonatal seizures may represent a first or even the only sign of central nervous system dysfunction. However, establishing the diagnosis of neonatal seizures poses several problems, and clinical observation is not sufficient in many cases. Neonatal polysomnography is a valuable tool both in the diagnostic and in the prognostic assessment of neonatal seizures. The present text reviews some technical aspects related to neonatal polysomnographies, and its usefulness in the area of suspected neonatal seizures. Moreover, some questions are raised regarding rhythmic discharges and their significance as a possible ictal and interictal epileptic pattern in the neonate.