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After an extensive evaluation process by specialists in Children’s Hospital Boston’s Epilepsy Program, Gwen Guay had surgery to remove the pea-sized piece of her brain causing her epileptic seizures. Since her team studied every detail of her brain’s functioning during her in-depth, pre-surgery assessment, they had a wealth of brain images, recordings of brain activity and other data, which they shared with researchers so they could learn more about epilepsy and how the brain works. Gwen and her parents were also eager to help advance science, and agreed to participate in several additional research studies during their stay at Children’s. Some of them are below.
In order to generate a detailed map of Gwen’s brain’s functions millimeter by millimeter, surgeons opened Gwen’s skull and placed thin strips of silicon studded with 108 electrodes directly on her brain. Once she woke up, computers recorded her brain’s electrical activity while she performed various tasks; this helped her epileptologists pinpoint the source of her seizures. Additionally, a team of Children’s researchers, led by Gabriel Kreimen, PhD, MSc, of Ophthalmology, used the data for another reason: to learn about how the brain identifies objects so quickly.
As a computer recorded signals generated by electrodes in her head, Gwen watched scenes from Disney movies. Kreimen’s team watched how her brain activity was synchronized to images in the movie, frame by frame. As the brain’s vision algorithms become clearer, the data could lead to a more precise analysis of signals that could make epilepsy surgery safer and more effective. But Kreiman also envisions teaching the algorithms to computers, which could act as an additional sets of eyes, helping to do things as wide-ranging as spotting terrorists in airports, helping drivers avoid collisions or scanning tumor samples for malignancy. Kreiman even imagines brain-computer interfaces that would give blind people at least partial sight.
Before Gwen had surgery to remove the piece of brain causing her seizures, her team created a “blueprint” of her brain based on numerous brain imaging tests. Her surgeons used this map to find the misfiring bit of brain. But these detailed configurations never exactly match what the surgeons see after they open a patients’ skull, since the brain’s shape shifts—up to several centimeters—when it becomes exposed, due to gravity, pressure changes and a loss of cerebrospinal fluid. The epileptic tissue also slightly changes position—potentially becoming dangerously close to healthy brain—which complicates a surgeon’s navigational process.
Children’s Director of Radiology Research, Simon Warfield, PhD, is tackling this problem. His newest effort is using diffusion tensor imaging to create a 3-D picture of the brain during the actual surgery. The images, which can be taken in just four minutes, help show the fiber tracts of the brain and gives insight into how the brain morphs during surgery. This kind of imaging is almost never done—Children’s is one of two hospitals in the world that have this technology—and Gwen was one of Children’s first patients to have it used.
It will likely take the researchers years before they can prove that the imaging benefits patients, but according to Warfield, it’s already clear that it will be a valuable safety tool for surgeons. There’s also potential for increasing the number of patients who are candidates for surgery, since improved imaging can lead to a better understanding of how the brain changes around epileptic areas.
Soon after surgeons removed Gwen’s epileptic brain tissue, they put it into oxygenated fluid and handed it over to a team of neuroscientists who had the rare chance to study this kind of abnormal brain tissue that still had living cells in it. “It’s a real window into what is actually going on in epileptic brain,” says Children’s neuroscientist Frances Jensen, MD, whose research focuses on the effect of seizures on brain development and why some patients are resistant to antiepileptic drugs.
Under a microscope, Jensen’s team of researchers studies this kind of brain tissue to look for abnormal cells to see if the cells create a certain pattern. “If we see different proteins and genes expressed, it gives us the chance to see if we can develop drugs that target only those genes,” she says. The researchers try out experimental drugs on the extracted brain tissue, hoping to stop cells from seizing. Typically, they have to test out drugs on animals, whose brains fall short of human’s complex architecture; to actually test drugs on human tissue is a remarkable opportunity.
Several students from Massachusetts Institute of Technology (MIT)’s Media Laboratory have teamed up with Children’s to put their inventions to use. One group created a machine called FaceReader that can read facial expressions to help people with autism interpret facial expressions. But they saw another use for it. While Gwen was being monitored in a room 24-hours-a-day during standard pre-operative evaluation, the students mounted a video camera to capture her every facial expression and head movement. They will match it with recordings of her brain activity and use FaceReader to identify which parts of her brain were being used when she appeared to be happy, angry or sad. This would be insightful in and of itself, but could also reveal how facial movements and emotion work together.
For another MIT project, researchers are collecting epilepsy patients’ physiological data collected through high-tech wristbands that patients wear. The bands sense changes in the body through small electrodes embedded in the fabric. Gwen diligently wore hers, and the wristband logged changes in her nervous system, picking up every change that can be captured on the surface of her skin, like an increase in sweating. The researchers will synchronize the data with her brain recordings and look for patterns.
Both studies may hold the possibility of being able to find ways to predict seizures—either through subtle facial signals or physiological data. If patients were able to predict when they were about to have a seizure, it would greatly improve the quality of life for people with epilepsy. |
