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Predicting risk for infantile spasms after acute symptomatic neonatal seizures

newborn

Infantile spasms (IS) is a severe epilepsy in early childhood. Early treatment of IS provides the best chance of seizure remission and favorable developmental outcome.

Taeun Chang, M.D., director of the Neonatal Neurology and Neurocritical Care Program at Children’s National Hospital, participated in a study with other national pediatric experts which aimed to develop a prediction rule to accurately predict which neonates with acute symptomatic seizures will develop IS.

The group of researchers found that multiple potential predictors were associated with IS, including Apgar scores, EEG features, seizure characteristics, MRI abnormalities and clinical status at hospital discharge. The final model born from this work included three risk factors: (a) severely abnormal EEG or ≥3 days with seizures recorded on EEG, (b) deep gray or brainstem injury on MRI and (c) abnormal tone on discharge exam.

The significance of these findings is that IS risk after acute symptomatic neonatal seizures can be stratified using commonly available clinical data. No child without risk factors, vs >50% of those with all three factors, developed IS. This risk prediction rule may be valuable for clinical counseling as well as for selecting participants for clinical trials to prevent post‐neonatal epilepsy. This tailored approach may lead to earlier diagnosis and treatment and improve outcomes for a devastating early life epilepsy.

Read the full study in Epilepsia.

EEG with electrical activity of abnormal brain

Speckle tracking echo reveals possible biomarker for SUDEP risk

EEG with electrical activity of abnormal brain

A study published in the journal Epilepsia used speckle tracking echocardiography to detect subtle changes in heart function found in pediatric patients with refractory epilepsy when compared to controls. Children with refractory epilepsy had impaired systolic ventricular strain compared to controls, not correlated to epilepsy history. These differences in ventricular function may be a biomarker that can indicate someone with epilepsy is at higher risk for Sudden Unexpected Death in Epilepsy (SUDEP).

Speckle tracking echocardiography is a non-invasive technique where software automatically identifies and tracks individual “speckles” of the myocardial wall on a routine echocardiogram in order to directly quantify the extent of contraction.

The study’s first authors, John Schreiber, M.D., medical director of Electroencephalography (EEG) and director of the Epilepsy Genetics program, and Lowell Frank, M.D., advanced imaging cardiologist and director of the Cardiology Fellowship Training program, both at Children’s National Hospital, answered some questions about the study findings.

Why is this important work?

Sudden unexpected death in epilepsy (SUDEP) is a rare but devastating consequence of epilepsy. Some of the proposed mechanisms of SUDEP implicate brain stem, cardiac and respiratory pathways.

This study identified alterations in ventricular function that may serve as one potential biomarker for SUDEP risk that can be evaluated non-invasively and regularly.

How will this work benefit patients?

Identification of children or adults with markedly impaired ventricular strain or diastolic function may provide the opportunity to implement a targeted treatment or monitoring strategy to prevent SUDEP.

What did you find that excites you? What are you hoping to discover?

These differences in cardiac strain were true for all patients with refractory epilepsy as a whole, not one particular group. This suggests that refractory convulsive epilepsy itself, rather than other patient-specific factors, produces these changes. Thanks in part to a grant from the Dravet Syndrome Foundation, the team is currently examining a cohort of patients with epilepsy due to pathogenic variants in sodium channel genes, SCN1A and SCN8A, to determine if these patients have greater degrees of impaired cardiac strain. SCN1A and SCN8A are also expressed in the heart, and patients have a considerably higher risk of SUDEP. It will be particularly exciting to examine for differences in specific genetic epilepsies.

How is this work unique?

Strain has been evaluated in many disease states in adult and pediatric populations and may be more sensitive to early myocardial damage than traditional measures of systolic and diastolic function. Children’s National Hospital has been an innovator in using speckle tracking echocardiography and similar techniques to evaluate subtle changes in heart function. This study is a great example of collaboration between The Comprehensive Pediatric Epilepsy Program and the Children’s National Heart Institute that is driving innovative research at Children’s National Hospital.

Autonomic nervous system appears to function well regardless of mode of childbirth

Late in pregnancy, the human body carefully prepares fetuses for the rigors of life outside the protection of the womb. Levels of cortisol, a stress hormone, ramp up and spike during labor. Catecholamines, another stress hormone, also rise at birth, helping to kick start the necessary functions that the baby will need to regulate breathing, heartbeat, blood pressure and energy metabolism levels at delivery. Oxytocin surges, promoting contractions for the mother during labor and stimulating milk production after the infant is born.

These processes also can play a role in preparing the fetal brain during the transition to life outside the womb by readying the autonomic nervous system and adapting its cerebral connections. The autonomic nervous system acts like the body’s autopilot, taking in information it needs to ensure that internal organs run steadily without willful action, such as ensuring the heart beats and eyelids blink at steady intervals. Its yin, the sympathetic division, stimulates body processes while its yang, the parasympathetic division, inhibits them.

Infants born preterm have reduced autonomic function compared with their full-term peers and also face possible serious neurodevelopmental impairment later in life. But is there a difference in autonomic nervous system function for full-term babies after undergoing labor compared with infants delivered via cesarean section (C-section)?

A team from the Children’s National Inova Collaborative Research Program (CNICA) – a research collaboration between Children’s National in Washington, D.C., and Inova Women’s and Children’s Hospital in Virginia – set out to answer that question in a paper published online July 30, 2019, in Scientific Reports.

They enrolled newborns who had experienced normal, full-term pregnancies and recorded their brain function and heart performance when they were about 2 days old. Infants whose conditions were fragile enough to require observation in the neonatal intensive care unit were excluded from the study. Of 167 infants recruited for the prospective cohort study, 118 newborns had sufficiently robust data to include them in the research.  Of these newborns:

  • 62 (52.5%) were born by vaginal delivery
  • 22 (18.6%) started out with vaginal delivery but ultimately switched to C-section based on failure to progress, failed labor induction or fetal intolerance to labor
  • And 34 (28.8%) were born by elective C-section.

The CNICA research team swaddled infants for comfort and slipped electrode nets over their tiny heads to simultaneously measure heart rate variability and electrocortical function through non-invasive techniques. The team hypothesized that infants who had been exposed to labor would have enhanced autonomic tone and higher cortical electroencephalogram (EEG) power than babies born via C-section.

“In a low-risk group of babies born full-term, the autonomic nervous system and cortical systems appear to function well regardless of whether infants were exposed to labor prior to birth,” says Sarah B. Mulkey, M.D., Ph.D., a fetalneonatal neurologist in the Division of Fetal and Transitional Medicine at Children’s National and the study’s lead author.

However, infants born by C-section following a period of labor had significantly increased accelerations in their heart rates. And the infants born by C-section during labor had significantly lower relative gamma frequency EEG at 25.2 hours old compared with the other two groups studied.

“Together these findings point to a possible increased stress response and arousal difference in infants who started with vaginal delivery and finished delivery with C-section,” Dr. Mulkey says. “There is so little published research about the neurologic impacts of the mode of delivery, so our work helps to provide a normal reference point for future studies looking at high-risk infants, including babies born preterm.”

Because the research team saw little differences in autonomic tone or other EEG frequencies when the infants were 1 day old, future research will explore these measures at different points in the newborns’ early life as well as the role of the sleep-wake cycle on heart rate variability.

In addition to Dr. Mulkey, study co-authors include Srinivas Kota, Ph.D., Rathinaswamy B. Govindan, Ph.D., Tareq Al-Shargabi, MSc, Christopher B. Swisher, BS, Laura Hitchings, BScM, Stephanie Russo, BS, Nicole Herrera, MPH, Robert McCarter, ScD, and Senior Author Adré  J. du Plessis, M.B.Ch.B., MPH, all of Children’s National; and Augustine Eze Jr., MS, G. Larry Maxwell, M.D., and Robin Baker, M.D., all of Inova Women’s and Children’s Hospital.

Financial support for research described in this post was provided by the National Institutes of Health National Center for Advancing Translational Sciences under award numbers UL1TR001876 and KL2TR001877.