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Advances in deep brain stimulation offer relief for Parkinson’s patients

June 2017

Refinements in deep brain stimulation (DBS), including new systems and imaging technology, are improving the quality of life for patients affected by Parkinson’s disease. The chronic neurodegenerative disorder—characterized by tremor, slowed voluntary movements, impaired gait and balance, and muscle rigidity—affects a reported 0.3% of the population, and its prevalence increases among older populations.1 Parkinson’s disease is the 10th leading cause of death among those 65 years old and older and carries a significant economic burden.1, 2 About 60,000 new cases occur every year in the United States with thousands more likely undectected.3

Treatment seeks to increase striatal dopamine, and drugs such as levodopa reduce symptoms in most patients. Eventually, carbidopa-levodopa therapymproduces less reliable and less predictable results and over time many patients experience motor complications such as dyskinesia and motor fluctuations.1 DBS, first approved by the U.S. Food and Drug Administration in 1997, can ameliorate these drug-related side effects and improve the movement symptoms associated with Parkinson’s disease.1, 4 In the procedure, neurosurgeons, guided by advanced imaging techniques, and neurologists specializing in brain mapping place leads with electrodes in the subthalamic nucleus (STN) or globus pallidus internus. The leads connect to a pulse generator, which is implanted in a following procedure and programmed to send electrical signals that modulate the brain signals causing the movement problems and drug-induced side effects. DBS is not a cure, and some Parkinson’s-related conditions such as balance problems and cognitive decline are not likely to improve with stimulation. The procedure, however, can markedly improve tremor, stiffness, and slowness of movement; reduce medication requirements; and improve the response to carbidopa-levodopa as well as ameliorate many motor complications associated with its long-term use.

June-2017-Consult-DBS-Feature-Article-Main-Image- a170411 UofMf 027-copy
— University of Minnesota physicians Michael Park, MD, PhD, and Jerrold Vitek, MD, PhD, lead research efforts into deep brain stimulation as a treatment for Parkinson’s disease. Photo by Scott Streble.

Appropriate patient selection and optimal electrode placement are key to improved outcomes with DBS.4 Patients who continue to respond to medication, even if only intermittently, or who have tremor or dystonia not responsive to medication are good candidates. Patients in whom medical therapy is not effective in improving any symptoms in spite of trying multiple drugs at increased doses are not considered good candidates. Screening prospective patients for their suitability for DBS requires a team-based approach, employing neurologists, neuropsychologists, radiologists, and neurosurgeons.

Optimal electrode placement is also critical.4, 5 Misplacement of leads by as little as 1 mm can stimulate adjacent tissues, causing undesirable side effects, such as unwanted movement and muscle contraction.4 Recent 3-dimensional imaging technology better delineates the STN and other structures, facilitating more accurate lead placement.6 New FDA-approved directional leads direct stimuli to steer current and mitigate side effects.

In September 2016, University of Minnesota was designated a Udall Center of Excellence for Parkinson Disease Research, one of only 9 in the United States. Led by University of Minnesota Health neurologist Jerrold Vitek, MD, PhD, the center includes a multidisciplinary team of neurologists, neurosurgeons, neuroscientists, and biomedical engineers. Physicians affiliated with the center are currently recruiting patients for clinical trials investigating new DBS systems and technologies. (See Case Study). One study underway employs advanced imaging and intraoperative techniques to delineate brain structure and electrophysiologic changes in normal and affected patients. The study makes use of one of the world’s few 7-Telsa magnetic resonance imaging (MRI) devices to improve accuracy of electrode placement into the target areas.6 Another investigation seeks to develop new stimulation approaches addressing the pallidum, an area important for controlling voluntary movement.

References

  1. Hickey P, Stacy M. Deep brain stimulation: a paradigm shifting approach to treat Parkinson’s disease. Front Neurosci. 2016;10:173
  2. Heron M. Deaths: Leading causes in 2014. National Vital Statistics Reports. 2016;65(5):1-96.
  3. Parkinson’s Disease Foundation. Statistics on Parkinson’s. www.pdf.org/en/parkinson_statistics. Accessed April 7, 2017.
  4. Miocinovic S, Somayajula S, Chitnis S, Vitek JL. History, applications, and mechanisms of deep brain stimulation. JAMA Neurol. 2013;70(2):163-171.
  5. Bronstein JM, Tagliati M, Alterman RL, Lozano AM, Volkmann J, Stefani A, et al. Deep brain stimulation for Parkinson disease. Arch Neurol. 2011;68(2):165-171.
  6. Plantinga BR, Temel Y, Duchin Y, Uludag K, Patriat R, Roebroeck A, et al. Individualized parcellation of the subthalamic nucleus in patients with Parkinson’s disease. Neuroimage. 2016 Sep 26 pii: S1053-8119(16)30486-4. doi: 10.1016/j.neuroimage.2016.09.023.

When to refer

University of Minnesota Health neurologists, neurosurgeons, and affiliated care teams can diagnose and treat multiple neurological and motor system disorders, including Parkinson’s disease, dystonia, epilepsy, and essential tremor. Our team of specialists include neurologists, neurosurgeons, advanced imaging specialists, and physical therapy and rehabilitation specialists, among others. Our physicians are at the forefront of research into therapies for Parkinson’s disease and can make the most advanced imaging systems and treatments available to patients. We are pioneers in the use of deep brain stimulation (DBS). Individual team members have been involved in early studies on its use and development in the United States, and since 1997, we have treated well over 1,500 patients with DBS. We can also give patients access to 7-Tesla MRI technology at University of Minnesota. The highly detailed scans produced with this MRI technology can significantly aid neurosurgeons in accurately placing DBS devices.

Our team of specialists work together to find the optimal treatment for each individual patient. Several treatment options exist for affected adults depending on the stage of the disease and severity of symptoms. These include exercise, massage, nutritional therapy, oral medication, and DBS. Proper selection criteria guides treatment options for individual patients.

Collaborative Care

Our multidisciplinary team of physicians and staff work closely together to coordinate care for each patient. We also work closely with referring providers and make every effort to keep them informed of patients’ care. Our staff provides detailed reports, from diagnosis to treatment and follow-up, and we work with the referring provider to extend communication and support to patients and their families.

For further information or to refer a patient, clinicians can call 612-672-7000. To find clinical trials involving patients with Parkinson’s disease, visit studyfinder.umn.edu.

The 2017 University of Minnesota Health Adult Specialty Directory is now available. To request a free copy, visit mhealth.org/for-medical-professionals/adultspecialty-directory.

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