Pinpointing where seizures are coming from, by looking between the seizures

May 2, 2017
Researchers pose in front of a GC map. Credit: Boston Children's Hospital

A computational approach developed at Boston Children's Hospital, described in the journal Neurosurgery, published online May 2, 2017, could enable more patients with epilepsy to benefit from surgery when medications do not help. The approach streamlines the seizure monitoring process required for surgical planning, making surgery a more feasible and less risky option for patients.

Currently, for some , pinpointing the diseased brain areas where their seizures originate requires invasive surgery to place grids of electrodes on the brain's surface. This is followed by long-term electroencephalography (EEG) monitoring—typically for a week—while doctors wait for a seizure to happen. Then, patients must undergo a second brain operation to remove the diseased tissue.

The new technology, developed by Joseph Madsen, MD, Director of Epilepsy Surgery at Boston Children's Hospital, and Eun-Hyoung Park, PhD, a computational biophysicist in the Department of Neurosurgery, could allow patients to be monitored in one short session, without the need to observe an actual seizure. Patients could then proceed directly to surgery, avoiding a second operation.

Effective use of this technology could cut the cost and risk by more than half by reducing the current two-stage procedure to one-stage, the researchers say.

"We know that the diseased brain network responsible for the seizures is there all along," says Madsen. "So rather than wait for the patient to have a seizure, we set out to find patterns of interaction between various points in the brain that might predict where seizures would eventually start."

Looking between the seizures

To identify the brain areas causing the seizures, Madsen and Park applied a special algorithm to analyze patients' interictal EEG data—data captured between their seizures. They randomly selected 25 patients with hard-to-treat epilepsy who previously had long-term EEG monitoring at Boston Children's, and analyzed data from the first 20 seizure-free minutes of the patients' EEGs.

Their algorithm, known as Granger causality analysis, is based on a statistical approach developed Sir Clive Granger (for which he won the Nobel Prize in Economics in 2003). Madsen and Park adapted the Granger method, originally used for economic forecasting, to calculate the probability that activity at one brain location predicts subsequent activity at other brain locations strongly enough to be considered causative. Their analysis generated a map of the causal relations in each patient's epileptogenic network, which Park and Madsen superimposed over images of the brain.

They then showed that the regions predicted to be causing seizures strongly correlated with actual causative regions on EEGs—as read by ten board-certified epileptologists, usually many days later.

Madsen and Park have shown that their calculations can be done quickly enough to allow data obtained in the operating room to potentially influence surgical decision-making. They now are investigating how the Granger causality method can best augment readings of EEGs by trained neurophysiologists.

"We still need to validate and refine our approach before it can be used clinically," notes Madsen. "But we are hopeful that these advanced computer applications can help us treat more children with epilepsy—with less risk and lower cost."

Explore further: Robot reduces need for open brain surgery to map epileptic seizures

Related Stories

Robot reduces need for open brain surgery to map epileptic seizures

January 23, 2017
A minimally invasive robotic device is eliminating the need for some patients to undergo open brain surgery to pinpoint the origin of their epileptic seizures. The device, in use at Duke and a small handful of epilepsy centers ...

Using network science to help pinpoint source of seizures

December 17, 2015
The ability to reliably pinpoint the anatomical source of epileptic seizures, different for each patient, remains elusive. One third of patients do not respond to medication and an alternative can be surgery to locate and ...

Granger causality test can make epilepsy surgery more effective

November 4, 2014
A new statistical test that looks at the patterns of high-frequency network activity flow from brain signals can help doctors pinpoint the exact location of seizures occurring in the brain and make surgery more effective, ...

Treatments available for drug-resistant epilepsy

August 22, 2016
One in 26 people will develop epilepsy – a chronic disease characterized by unpredictable seizures—in their lifetime.

Long-term gains with early epilepsy surgery

January 23, 2017
There are important, long-term gains from hastening the processes around surgical interventions against epilepsy - before the disease has had too much negative impact on brain functions and patients' lives. These are some ...

New mech­an­ism un­der­ly­ing epi­lepsy found

February 27, 2017
Prolonged epileptic seizures may cause serious problems that will continue for the rest of a patient's life. As a result of a seizure, neural connections of the brain may be rewired in an incorrect way. This may result in ...

Recommended for you

Offbeat brain rhythms during sleep make older adults forget

December 15, 2017
Like swinging a tennis racket during a ball toss to serve an ace, slow and speedy brainwaves during deep sleep must sync up at exactly the right moment to hit the save button on new memories, according to new UC Berkeley ...

Our memory shifts into high gear when we think about raising our children, new study shows

December 15, 2017
Human memory has evolved so people better recall events encountered while they are thinking about raising their offspring, according to a new study conducted by researchers at Binghamton University, State University of New ...

Study finds graspable objects grab attention more than images of objects do

December 15, 2017
Does having the potential to act upon an object have a unique influence on behavior and brain responses to the object? That is the question Jacqueline Snow, assistant professor of psychology at the University of Nevada, Reno, ...

Little understood cell helps mice see color

December 14, 2017
Researchers at the University of Colorado Anschutz Medical Campus have discovered that color vision in mice is far more complex than originally thought, opening the door to experiments that could potentially lead to new treatments ...

Scientists chart how brain signals connect to neurons

December 14, 2017
Scientists at Johns Hopkins have used supercomputers to create an atomic scale map that tracks how the signaling chemical glutamate binds to a neuron in the brain. The findings, say the scientists, shed light on the dynamic ...

Journaling inspires altruism through an attitude of gratitude

December 14, 2017
Gratitude does more than help maintain good health. New research at the University of Oregon finds that regularly noting feelings of gratitude in a journal leads to increased altruism.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.