by Anna Williams
Improving quality of life with
leading-edge deep brain stimulation.
Image by John Bavosi/Science Source
For patients with Parkinson’s disease, even everyday tasks like brushing their teeth or signing their name can present significant challenges. Severe tremors, involuntary movements and other motor symptoms characteristic of Parkinson’s often prevent patients’ from carrying on their day-to-day activities, especially as the disease progresses and symptoms become more difficult to control.
Within the Northwestern Medicine health system, an advanced surgical treatment called deep brain stimulation (DBS) is bringing a sense of control back to these patients.
The remarkable procedure, which involves implanting an electrical system into a patient’s brain to regulate the abnormal signaling in Parkinson’s, may sound futuristic to those unfamiliar with the treatment. In fact, DBS has been well-established over decades of use. And while the procedure does not cure Parkinson’s or alter the underlying course of the disease, DBS can change lives by easing debilitating symptoms.
Today, Northwestern Medicine hospitals are home to the busiest DBS program in the region, where a team of neurology specialists and an expert neurosurgeon are at the forefront in using leading-edge DBS techniques to improve quality of life for patients with Parkinson’s and other movement disorders, such as essential tremor and involuntary muscle contractions known as dystonia.
“We’ve led the way in using advanced devices in DBS and advanced techniques in the operating room to facilitate surgeries,” says Joshua Rosenow, MD, director of the Functional Neurosurgery and Epilepsy Surgery Program in the Department of Neurological Surgery. He performs the procedure at both Northwestern Medicine Central DuPage Hospital and Northwestern Memorial Hospital (NMH), which is ranked #9 in the nation for its neurology and neurosurgery program. “We’re always looking to get better. We’re always looking to optimize what we do and how we do it to help improve outcomes for patients.”
A Look Inside DBS
Deep brain stimulation has been approved by the Food and Drug Administration (FDA) since 1997 for essential tremor and medication-resistant Parkinson’s-related tremor. Still, many physicians believe that common misconceptions about DBS lead a large number of patients with Parkinson’s — which occurs in 1 to 2 percent of people over the age of 60 — to miss out on potential treatment.
“If you ask movement disorders experts across the spectrum, I think we would all say that deep brain stimulation is still vastly underutilized,” says Cindy Zadikoff, MD, associate professor of Neurology in the Division of Movement Disorders, and a neurologist who manages DBS patients at NMH.
“Even today, there are still plenty of patients who see DBS as science fiction or as a last-ditch effort,” agrees Rosenow, also a professor of Neurological Surgery, Neurology, and Physical Medicine and Rehabilitation. “But DBS is a fully accepted part of the disease treatment continuum. When used in the right situation, it really is something that produces a tremendous improvement in quality of life.”
Not everyone is a candidate for DBS. Before undergoing the procedure, patients with Parkinson’s receive a thorough assessment and discuss potential benefits and risks with their neurologist.
In general, DBS is only considered for patients who have lived with Parkinson’s for several years and experience significant symptom fluctuations throughout the day, despite optimal medical management.
“Deep brain stimulation doesn’t cure the diseases we are treating — and we spend a lot of time making sure patients understand that. But for Parkinson’s disease, it does take them back to a time when their fluctuations were minimal, and we can reduce medication,” explains Zadikoff, also an associate professor of Medical Education. “Our goal is to allow patients to go back to doing the things they like to do, and used to do.”
Deep Brain Stimulation
During the procedure, a neurosurgeon places a thin wire lead through a small opening in the patient’s skull (1) Electrodes (2) at the end of the lead reach into a specific area of the brain. An extension wire (3) connects this system to a neurostimulator (4) implanted in the chest. Programmed and adjusted by a neurologist, the device sends electrical impulses to the electrodes to regulate abnormal signaling in the brain and control the patient’s movement. Illustration by MCKIBILLO
During a DBS procedure, stimulating electrodes are implanted through a small opening in the skull into a specific area of the brain that controls movement (the exact location depends on the patient and his or her condition). Part of the surgery is performed while patients are awake and responsive, which helps ensure that the correct areas are being stimulated. The electrodes are connected to an extension wire that runs under the skin behind the ear and down the neck to a small device implanted in the chest. That device — a neurostimulator akin to a pacemaker — sends electrical impulses through the wire to the electrodes to regulate abnormal signaling in the brain, restoring normal function to the patient.
Finding the optimal target for stimulation is key. “I kid with patients and students that neurology and real estate are all about the same thing: location, location, location,” Zadikoff says. After the device has been properly implanted, programming that takes place after surgery also helps achieve an optimal response. Neurologists like Zadikoff make adjustments to the neurostimulator settings as needed, and also work with patients on modifications they can make at home to increase effectiveness.
For some symptoms, the effect of DBS can be immediate. “It really is just such a ‘wow’ moment,” Zadikoff says, referring to the point during surgery or programming when tremors settle, and patients can pick up a pen or steadily hold a drink in their hand again.
It can take longer for disorders like dystonia to respond to DBS, as well as other symptoms of Parkinson’s, such as bradykinesia (slow movement) and gait difficulty. And in general, DBS doesn’t improve Parkinson’s symptoms that didn’t previously respond to medication.
But for many patients, the therapy’s overall impact on quality of life is powerful — whether it’s the newfound ability to leave a walker at home, decrease medication or return to hobbies and routines enjoyed before their diagnosis.
“Many studies have now shown that DBS allows patients to reduce their medication and improve their quality of life,” Zadikoff says. “And when we simply ask patients, ‘how much better do you think you are?,’ they’ll usually tell us somewhere between 70 to 90 percent. This therapy really gives a lot back to patients.”
Toward Better Outcomes in DBS
Although DBS has been used for almost 30 years, the basic technology has remained largely the same over that time period — until recent years. Investigators at Northwestern and around the world are now helping to refine the technology behind DBS, with the ultimate goal of further improving outcomes for patients.
Zadikoff and Rosenow are both investigators in INTREPID, an ongoing randomized, double-blind clinical trial for a new device, called the Vercise DBS System, which delivers stimulation to the brain in a novel way.
“We’re able to stimulate areas in a more refined fashion,” Zadikoff explains. “The device is controlled by current, as opposed to voltage, which is a much more regulated and energy-efficient way of delivering this energy.”
CINDY ZADIKOFF, MD
JOSHUA ROSENOW, MD
One-year data from the trial, presented at the American Academy of Neurology meeting in April and the American Society for Stereotactic and Functional Neurosurgery meeting in June, demonstrated that the device is safe and effective in treating Parkinson’s symptoms. Vercise is now FDA-approved.
“We continue to be involved both on the local and national level in these sorts of studies to bring the most cutting-edge therapies to our patients,” Rosenow says. He notes that Northwestern Medicine was also one of the first centers to use and validate certain advanced surgical techniques in DBS, such as interoperative CT scanning to inform placement.
Michael Rezak, MD, PhD, a longtime advocate of DBS who directs the deep brain stimulation program at Central DuPage Hospital, also recently received the Distinguished Physician Award from the Parkinson’s Disease Research Society, which includes funding for research into movement disorders. He also serves on multiple national committees focused on DBS research.
In the future, investigators will continue to study enhanced DBS systems and surgical techniques, as well as explore new targets for stimulation that might address symptoms DBS currently doesn’t treat. There is also increasing research into the use of DBS in select cases of other disorders, such as epilepsy and obsessive-compulsive disorder. “I think that in the future, we are going to be seeing greater numbers of indications for DBS, particularly in the neuropsychiatric world,” Zadikoff says.
Of course, Northwestern investigators are also actively investigating a range of other therapies for movement disorders, to expand treatment options for patients who may not elect to undergo DBS.
For now, providers like Zadikoff, Rezak and Rosenow often say that working with patients with DBS remains one of the most rewarding aspects of their practice.
“Seeing the improvement in quality of life for these patients is really one of the most gratifying things we get as surgeons,” Rosenow says. “Knowing how we’ve helped preserve someone’s quality of life and improve how they live every day — that makes it all worth it for us.”
Image by Alfred Pasieka/Science Source