"I think cooling is the most promising approach," says Miller, who collaborates on cooling research led by a University of Washington colleague. "If a particular cooling temperature can be found that prevents seizures, but does not injure the brain or interfere with normal brain function, it would be possible to maintain the region of brain around the seizure focus at that temperature all the time, so that it would not be necessary to detect the seizures to apply the therapy."
Targeted drug delivery
The third possible mode of operation for closed-loop devices would use convection-enhanced drug delivery (CED). CED involves feeding seizure-halting medications directly to specific areas of brain tissue through an implanted catheter; the concept of CED is designed to avoid the systemic side effects of giving medications orally and having them suffuse through the bloodstream in order to reach the brain.
Yet CED may ultimately prove more useful on a set infusion schedule, rather than linked to a responsive, automated seizure-detection system. "Our current conception of how CED would be used in epilepsy is that patients would receive periodic infusions of a long-lasting antiseizure agent into the epileptic brain region," says Michael Rogawski, chair of neurology at the University of California, Davis, whose lab is working with British Columbia–based biopharmaceutical company MedGenesis Therapeutix to develop an implantable CED device for epilepsy. "Seizure control might be maintained for months," he says. "This approach greatly simplifies the technical challenges in comparison with a device that must sense and deliver a drug on a moment-to-moment basis."
Deep-brain stimulation
With electrical stimulation, too, some patients will find that an open-loop device that fires consistently works better—like the VNS, or Medtronic's Deep Brain Stimulation (DBS) implant for epilepsy, which the FDA is now reviewing. Similar to the company's widely-used DBS technology for Parkinson’s disease, the DBS for epilepsy is placed within the brain and consistently stimulates a region called the anterior nucleus of the thalamus, which helps control the electrical excitability of the cortex.
Unlike closed-loop devices, which typically require a distinct seizure focus, the DBS can be used to treat patients whose seizures appear to engulf the entire brain, or large portions of it, at once. "If you look at the population of patients who have these very unlocalizable, diffuse seizure disorders, folks who are having many, many seizures a day and are just devastated—if you can control some of those seizures even in some of those patients, you've done a great good for the families and the patients," says Dennis Spencer, chair of neurosurgery and director of the Epilepsy Surgery Program at Yale University School of Medicine. "We think that the DBS will open up a path for therapy."
Closing the loop
Closed-loop technologies for epilepsy face several hurdles. Skeptics note that brain surgery poses significant risks, and that the benefits of implanted devices will not always outweigh those dangers. There are also concerns about the possibility of false positives—detection of electrical activity that turns out not to be a seizure. "If the intervention did cause a transient interruption in brain function, it would be undesirable for the patient," Miller says. "For example, if the area that was being affected mediated language, the person might have a brief interruption in the ability to speak."
Researchers also acknowledge that in a condition as variable as epilepsy, there will never be a single solution, such as cooling, stimulation or drug delivery alone. "We may need to use more than one modality to fully control epilepsy," Osorio says. "But all of that hinges on the ability to detect in real time—and to quantify—seizures."
Although the design of first-generation closed-loop devices is just beginning, theoretical development of the second generation is already underway. Because people with epilepsy never know when and where a seizure will occur, the goal of second-generation closed-loop devices will be finding a way to predict seizures before they begin and intervene to prevent them. "You can detect seizures, but you're still detecting them too late to really have a major therapeutic possibility," Spencer says. "Prediction is where we're really looking to put our eggs—in that basket."
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8 Comments
Add CommentAnyone read Michael Chrichton's "The Terminal Man"? http://en.wikipedia.org/wiki/The_Terminal_Man
Reply | Report Abuse | Link to thisTeach a dog to flip the switch:
Reply | Report Abuse | Link to thishttp://www.epilepsy.com/articles/ar_1084289240
an very decent audio complement to this story:
Reply | Report Abuse | Link to thisPredicting and preventing epileptic seizures with neural implants:
http://upclose.unimelb.edu.au/episode/197-predicting-and-preventing-epileptic-seizures-neural-implants
All of this was predicted (actually demonstrated to be inevitable) in the most important work on psychology, ethics, and philosophy of the 20th Century, B.F.Skinner's "Beyond Freedom and Dignity". One can think of many benefits of implants, such as this one for epilepsy, and perhaps for such ailments as schizophrenia, bipolarism, even child molestation and other criminal acts. In fact, one can envision, as Skinner hinted, a world where everyone wears such a device that overrides tendencies deemed antisocial. The problem, of course, is who decides what to inhibit, what to advance?
Reply | Report Abuse | Link to thisThanks to Aliyah Baruchin for this very informative article and for raising awareness, once again, of epilepsy.
Reply | Report Abuse | Link to thisWe applaud all you are doing for the millions of people worldwide who suffer from this disease.
Best,
Danielle Davis
CURE (Citizens United for Research in Epilepsy)
So glad to see advances in epilepsy.Hopefully this will prevent deaths due to epilepsy. My family lost my brother in Dec at the age of 47, due to his heart stopping from seizures. Thank you doctors/researchers for trying to help people with this illness.
Reply | Report Abuse | Link to thisI want a miracle to have my son's seizures disappear. Patient, sensitive, handsome, healthy and now 24 , he has tolerated the seizures since he was 3. I pray for the talents and brilliance of Dr. Brian Litt and his colleagues so that they may help my son and people affected by epilepsy.
Reply | Report Abuse | Link to thisAll of this does sound rather nice, but I do have to wonder just a few things...
Reply | Report Abuse | Link to this1. How much this research is costing
2. If it were available for patients, how much would the cost be for them
3. When do scientists/doctors hope that this treatment would be available for patients?
Please forgive me for asking, but we're researching technological advancements in anatomy and I was curious.
-High School Student