Future deep brain stimulators may even include sensors that allow it to respond dynamically to changes in brain patterns, said Brett Wall, senior vice president of brain therapies at Medtronic. The company also hopes to reduce the size of devices, eventually making generators rechargeable or even small enough to embed directly on top of the skull, Wall said.
Researchers also are exploring ways to create a non-invasive form of DBS. MIT scientists have developed a new method to stimulate cells inside the brain non-invasively, using multiple electric fields applied from outside the organ, according to a study conducted on mice that had its results published in the scientific journal Cell in June.
Wodziak cautioned though that the surgery is only optimal for patients that will drastically benefit from it. Due to the nature of the surgery, patients opting for DBS it must undergo a bevy of tests from an army of specialists: A neurologist and neuropsychologist to screen patients. A neurosurgeon to perform the implant. A psychiatrist and rehab team including physical therapists, occupational therapists, and speech therapists to assist recovery.
The best candidates for DBS
Have had PD symptoms for at least five years.
Have "on/off" fluctuations (when a person cycles between "on" time, when the medication is working to control symptoms, and "off" time, when medication has worn off and PD symptoms return), with or without dyskinesia. Dyskinesia is involuntary, irregular, writhing movement that can range from mild to violent and can sometimes be unpredictable.
Continue to have a good response to PD medications, especially carbidopa/levodopa (though the duration of response may be insufficient).
Have tried different combinations of carbidopa/levodopa and dopamineagonists under the supervision of a movement disorder neurologist or specialist.
Have tried other PD medications – such as entacapone, tolcapone, selegiline,apomorphine or amantadine – without beneficial results.
Have PD symptoms that interfere with daily activities.
(Source: National Parkinson Foundation)
Parkinson's disease patients are also advised to consult with a movement disorders specialist, a neurologist who has completed specialized training in PD and movement disorders, or in the least with neurologists in practice who have become experts in this area through their experience caring for many patients and by taking continuing medical education courses.
"We don't put it in first," Okun said. "We very carefully go through an interdisciplinary evaluation, we find out what's disabling to the patient, we have to make a conscious decision; can our technology tackle all the symptoms in our patient?"
The treatment is meant to be a supplement to, and not a replacement for, medication and other treatments. Patients also need to be aware that many post-operative visits for both DBS programming and medication adjustments will be required, most frequently during the first 6 months following implantation. Many medical centers that offer DBS also require monthly visits for the first six months. DBS is removable and reversible.
It's not a cure for Parkinson's Disease.
Michael J. Fox, the actor who has become synonymous with the fight to find a cure for Parkinson's and whose foundation offers guidance for those considering the procedure, has spoken in the past about the potential benefits of DBS, but also its limitations. He was first diagnosed in 1991 and in the late 1990s, Fox had a type of brain surgery to relieve his tremors, a thalamotomy — which destroys a small portion of brain tissue — before DBS became an option.
Fox told CNN's Chief Medical Correspondent Dr. Sanjay Gupta back in 2010 about his decision to not pursue DBS: "The next time they go in my brain, I want them to get it done. … If there is something that they can do that will be curative or restorative … in a much more fundamental way than a mechanical stop gap, a kind of pacemaker. ... That's just my personal preference, but it's been tremendous in people's lives, hundreds I've met, and thousands that have had the procedure, deep brain stimulation. It's been huge, the improvement ... the people that couldn't walk, people that had a hard time functioning."