Precision Treatment for Pediatric Epilepsies: Role of Stereo-EEG in Planning Epilepsy Surgery

sEEG has revolutionized how drug-resistant epilepsy is managed. It not only has much lower morbidity, but also the ability to survey parts of the brain that can’t be surveyed with grids. Follow one patient’s dramatically improved outcomes after precision monitoring and epilepsy surgery.

At Children’s Hospital of Philadelphia (CHOP), advanced imaging and robot-assisted techniques guide epilepsy treatment options and ensure the safest, most targeted patient care.

For one particular young patient followed in this case, this precision treatment has been life changing. At one point in her life, Emily suffered 90 seizures a day. But now, thanks to resection surgery at Children’s Hospital of Philadelphia, the 11-year-old is seizure-free. The same diagnostic capabilities and technologies that helped Emily are changing the outcomes for many children with difficult-to-treat epilepsies.

When Emily was 22 months old, her parents noticed concerning symptoms that appeared neurological — eyes rolling up into her head, spasticity in her neck, and her arms stiffening.

After undergoing an electroencephalogram (EEG) at a hospital near her home, treating physicians diagnosed a seizure and prescribed medication. Seeking a more conclusive diagnosis, Emily’s parents contacted Children’s Hospital of Philadelphia. The Pediatric Epilepsy Program at CHOP specializes in the diagnosis, evaluation and treatment of children with epilepsy.

Management of a complex seizure disorder

A brain MRI at CHOP revealed that Emily had extensive left hemisphere injury from a presumed perinatal stroke. This brain injury led to developmental impairments including right arm weakness and learning difficulties, but was also the cause of her seizures. After the first anti-seizure medications failed to stop the seizures completely, other treatment options were considered, including the ketogenic diet.

While on the diet, Emily’s seizure frequency dropped from 80-90 tonic/atonic seizures daily to near-seizure freedom within six weeks. Her language and social skills advanced significantly during this period of seizure control. But over time, when she weaned off the diet, seizures returned.

When Emily was 9 years old, she started having convulsive seizures twice a week. Her physician, pediatric neurologist Sudha Kessler, MD, MSCE, recommended evaluation for epilepsy surgery to remove the section of brain generating the seizures.

Stereo-EEG monitoring to pinpoint seizure source for epilepsy surgery

After further tests, including inpatient EEG monitoring and magnetoencephalography (MEG), Dr. Kessler and her team recommended stereoelectroencephalography (sEEG), which involves the placement of needle electrodes to precisely pinpoint the area of brain producing seizures to determine if it can be safely removed.

In the last five to 10 years, sEEG has revolutionized how drug-resistant epilepsy is managed. It not only has much lower morbidity, but it also has the ability to survey parts of the brain you can’t survey with grids. It can also survey both sides of the brain and multiple lobes at once.

The strategy was to use sEEG to confirm that Emily’s seizures were starting in the most injured parts of her left hemisphere, confirm that her frontal lobe was not involved at onset, confirm that the right side of her brain was not involved at onset, and determine if she had language function in her left frontal lobe. The sEEG study confirmed all of these things. Emily had brain injury in her temporal, occipital and parietal lobes, including immediately behind her primary sensory strip, which is right behind the primary motor strip; these areas govern movement on the opposite side of the body.

Emily suffered her last seizure the morning before epilepsy surgery. Pediatric neurosurgeon Benjamin Kennedy, MD, resected her left temporal, parietal and occipital lobes right up to the primary sensory strip. Emily recovered without any neurologic deficit and has been seizure-free since.

Emily returns to CHOP every six months to check in with Dr. Kessler. She still takes one seizure medication to ensure the seizures stay at bay, and will likely need to for the rest of her life.

Searching for the genetic cause of epilepsy

We are increasingly identifying genetic causes in children with presumed acquired epilepsies. Learning more about the drivers of epilepsy will lead to more personalized care, not just with medicine, but for candidacy for vagus nerve stimulation (VNS) and deep brain stimulation (DBS) as well. Also, with better understandings of epileptic networks, we will have better targeting for resection, ablation and responsive neurostimulation (RNS), leading to better outcomes.

CHOP’s Epilepsy Neurogenetics Initiative (ENGIN) is a specialized program that strives to diagnose, treat and ultimately cure epilepsy through imaging, neurophysiologic testing, genetic testing and individualized therapy. Through ENGIN, we will provide increased access to genetic testing and incorporate a genetic evaluation into the diagnostic workup of all children with unexplained epilepsy. Identifying a genetic cause remains a critical first step in understanding the underlying biological mechanisms of seizure disorders, which we hope will enable the development of new breakthroughs in terms of treatments for epilepsies.