Effects of hypoxic-ischemic encephalopathy and whole-body hypothermia on neonatal auditory function: a pilot study.

We assessed the effects of hypoxic-ischemic encephalopathy (HIE) and whole-body hypothermia therapy on auditory brain stem evoked responses (ABRs) and distortion product otoacoustic emissions (DPOAEs). We performed serial assessments of ABRs and DPOAEs in newborns with moderate or severe HIE, randomized to hypothermia ( N = 4) or usual care ( N = 5). Participants were five boys and four girls with mean gestational age (standard deviation) of 38.9 (1.8) weeks. During the first week of life, peripheral auditory function, as measured by the DPOAEs, was disrupted in all nine subjects. ABRs were delayed but central transmission was intact, suggesting a peripheral rather than a central neural insult. By 3 weeks of age, peripheral auditory function normalized. Hypothermia temporarily prolonged the ABR, more so for waves generated higher in the brain stem but the effects reversed quickly on rewarming. Neonatal audiometric testing is feasible, noninvasive, and capable of enhancing our understanding of the effects of HIE and hypothermia on auditory function

Loss of Tsc2 in radial glia models the brain pathology of tuberous sclerosis complex in the mouse

Tuberous sclerosis complex (TSC) is an autosomal dominant, tumor predisposition disorder characterized by significant neurodevelopmental brain lesions, such as tubers and subependymal nodules. The neuropathology of TSC is often associated with seizures and intellectual disability. To learn about the developmental perturbations that lead to these brain lesions, we created a mouse model that selectively deletes the Tsc2 gene from radial glial progenitor cells in the developing cerebral cortex and hippocampus. These Tsc2 mutant mice were severely runted, developed post-natal megalencephaly and died between 3 and 4 weeks of age. Analysis of brain pathology demonstrated cortical and hippocampal lamination defects, hippocampal heterotopias, enlarged dysplastic neurons and glia, abnormal myelination and an astrocytosis. These histologic abnormalities were accompanied by activation of the mTORC1 pathway as assessed by increased phosphorylated S6 in brain lysates and tissue sections. Developmental analysis demonstrated that loss of Tsc2 increased the subventricular Tbr2-positive basal cell progenitor pool at the expense of early born Tbr1-positive post-mitotic neurons. These results establish the novel concept that loss of function of Tsc2 in radial glial progenitors is one initiating event in the development of TSC brain lesions as well as underscore the importance of Tsc2 in the regulation of neural progenitor pools. Given the similarities between the mouse and the human TSC lesions, this model will be useful in further understanding TSC brain pathophysiology, testing potential therapies and identifying other genetic pathways that are altered in TSC

Standardized Treatment of Neonatal Status Epilepticus Improves Outcome

We aimed to decrease practice variation in treatment of neonatal status epilepticus by implementing a standardized protocol. Our primary goal was to achieve 80% adherence to the algorithm within 12 months. Secondary outcome measures included serum phenobarbital concentrations, number of patients progressing from seizures to status epilepticus, and length of hospital stay. Data collection occurred for 6 months prior and 12 months following protocol implementation. Adherence of 80% within 12 months was partially achieved in patients diagnosed in our hospital; in pretreated patients, adherence was not achieved. Maximum phenobarbital concentrations were decreased (56.8 vs 41.0 µg/mL), fewer patients progressed from seizures to status epilepticus (46% vs 36%), and hospital length of stay decreased by 9.7 days in survivors. In conclusion, standardized, protocol-driven treatment of neonatal status epilepticus improves consistency and short-term outcome

Evolution of the Sarnat exam and association with 2-year outcomes in infants with moderate or severe hypoxic-ischaemic encephalopathy: a secondary analysis of the HEAL Trial.

OBJECTIVE: To study the association between the Sarnat exam (SE) performed before and after therapeutic hypothermia (TH) and outcomes at 2 years in infants with moderate or severe hypoxic-ischaemic encephalopathy (HIE). DESIGN: Secondary analysis of the High-dose Erythropoietin for Asphyxia and EncephaLopathy Trial. Adjusted ORs (aORs) for death or neurodevelopmental impairment (NDI) based on SE severity category and change in category were constructed, adjusting for sedation at time of exam. Absolute SE Score and its change were compared for association with risk for death or NDI using locally estimated scatterplot smoothing curves. SETTING: Randomised, double-blinded, placebo-controlled multicentre trial including 17 centres across the USA. PATIENTS: 479/500 enrolled neonates who had both a qualifying SE (qSE) before TH and a SE after rewarming (rSE). INTERVENTIONS: Standardised SE was used across sites before and after TH. All providers underwent standardised SE training. MAIN OUTCOME MEASURES: Primary outcome was defined as the composite outcome of death or any NDI at 22-36 months. RESULTS: Both qSE and rSE were associated with the primary outcome. Notably, an aOR for primary outcome of 6.2 (95% CI 3.1 to 12.6) and 50.3 (95% CI 13.3 to 190) was seen in those with moderate and severe encephalopathy on rSE, respectively. Persistent or worsened severity on rSE was associated with higher odds for primary outcome compared with those who improved, even when qSE was severe. CONCLUSION: Both rSE and change between qSE and rSE were strongly associated with the odds of death/NDI at 22-36 months in infants with moderate or severe HIE

Risk of seizures in neonates with hypoxic-ischemic encephalopathy receiving hypothermia plus erythropoietin or placebo.

BACKGROUND: An ancillary study of the High-Dose Erythropoietin for Asphyxia and Encephalopathy (HEAL) trial for neonates with hypoxic-ischemic encephalopathy (HIE) and treated with therapeutic hypothermia examined the hypothesis that neonates randomized to receive erythropoietin (Epo) would have a lower seizure risk and burden compared with neonates who received placebo. METHODS: Electroencephalograms (EEGs) from 7/17 HEAL trial centers were reviewed. Seizure presence was compared across treatment groups using a logistic regression model adjusting for treatment, HIE severity, center, and seizure burden prior to the first dose. Among neonates with seizures, differences across treatment groups in median maximal hourly seizure burden were assessed using adjusted quantile regression models. RESULTS: Forty-six of 150 (31%) neonates had EEG seizures (31% in Epo vs 30% in placebo, p = 0.96). Maximal hourly seizure burden after the study drug was not significantly different between groups (median 11.4 for Epo, IQR: 5.6, 18.1 vs median 9.7, IQR: 4.9, 21.0 min/h for placebo). CONCLUSION: In neonates with HIE treated with hypothermia who were randomized to Epo or placebo, we found no meaningful between-group difference in seizure risk or burden. These findings are consistent with overall trial results, which do not support Epo use for neonates with HIE undergoing therapeutic hypothermia. IMPACT: In the HEAL trial of erythropoietin (Epo) vs placebo for neonates with encephalopathy presumed due to hypoxic-ischemic encephalopathy (HIE) who were also treated with therapeutic hypothermia, electrographic seizures were detected in 31%, which is lower than most prior studies. Epo did not reduce the proportion of neonates with acute provoked seizures (31% in Epo vs 30% in placebo) or maximal hourly seizure burden after the study drug (median 11.4, IQR 5.6, 18.1 for Epo vs median 9.7, IQR 4.9, 21.0 min/h for placebo). There was no anti- or pro-convulsant effect of Epo when combined with therapeutic hypothermia for HIE