Deep brain stimulation benefits advanced Parkinson's disease
1 September 2006
Minneapolis, USA. A study carried out in Germany and
Austria has found that Medtronic's (NYSE:MDT) Activa deep brain stimulation
therapy combined with medication is significantly more effective than
medication alone in treating motor symptoms of advanced Parkinson's disease.
The results were published in the published in the Aug. 31 issue of The New
England Journal of Medicine (NEJM).
Conducted at 10 academic medical centres in Germany and Austria, the
study included 156 patients with severe motor symptoms of Parkinson's
disease and rated improvements in motor function (among other outcomes)
after six months of treatment. Patients were randomly assigned to one of
two treatment groups: half were selected to receive medication plus
bilateral DBS of the subthalamic nucleus (STN), a brain structure
involved in regulating movement, using Medtronic's Kinetra(R)
neurostimulation system; and the other half were selected to receive
medication alone. At the time of enrollment in the trial, all patients
were under 75 years old, had been diagnosed with Parkinson's disease at
least five years previously, and suffered from impaired mobility despite
optimal treatment with medication.
Compared to medication alone, DBS of the STN caused significantly
greater improvements in motor function after six months. On average,
patients who received DBS plus medication showed a 41 percent
improvement in motor function (as measured by the motor examination
component of the Unified Parkinson's Disease Rating Scale (UPDRS-III)).
Medication-only patients showed no change on the same measure.
"In conclusion," the authors wrote, "this six-month study
demonstrated that subthalamic neurostimulation resulted in a
significantly and clinically meaningful improvement in ... patients
under 75 years of age who had advanced Parkinson's disease with severe
fluctuations in mobility and dyskinesia (involuntary movements caused by
medication). The patients who received neurostimulation had longer
periods and better quality of mobility with less dyskinesia."
Lead author Dr. Gunther Deuschl, professor of neurology and chairman
of the Department of Neurology at the University of Kiel in Germany,
explained the significance of the study's results: "DBS clearly provides
important benefits to Parkinson's patients who suffer troubling motor
symptoms despite optimal treatment with medication. It should therefore
be offered to this group of patients as soon as mobility problems can no
longer be managed sufficiently with medication."
While serious adverse events were more common with neurostimulation
than with medication alone and included a fatal intracerebral hematoma,
the total number of adverse events was higher among medication-only
patients. The authors stated that all of the non-fatal adverse events
"resolved without permanent complications" and that "most adverse events
were well-known medical problems associated with advanced Parkinson's
According to Dr. C. Warren Olanow, professor of neuroscience and
chairman of the Department of Neurology at the Mount Sinai School of
Medicine in New York, and former president of the Movement Disorder
Society: "This study provides further evidence supporting the use of DBS
as a therapy for advanced Parkinson's disease patients whose motor
symptoms cannot be satisfactorily controlled with medication."
Dr. Olanow served as a lead investigator in the global clinical trial
of DBS for Parkinson's disease that led to the therapy's approval by the
U.S. Food and Drug Administration in January 2002.
"We welcome the results of this latest study, which represent an
excellent addition to the clinical evidence for Activa DBS Therapy as a
treatment for Parkinson's disease," said Dr. Richard E. Kuntz, president
of Medtronic's Neurological division and senior vice president of
Medtronic, Inc. "As the pioneer and leader of this therapeutic
technology, Medtronic is committed to studying DBS for a variety of
clinical applications. We are also committed to advancing the technology
The study was supported by a grant from the German Federal Ministry
of Education and Research. Medtronic coordinated several investigator
meetings and covered the cost of supplemental patient insurance for
Affecting an estimated 1 million people in the United States alone,
Parkinson's disease is a complex, progressive and degenerative
neurological disorder that causes loss of control over body movements.
Motor symptoms include rigidity (stiffness or inflexibility of the limbs
and joints); bradykinesia/akinesia (slowness/absence of movement); and
tremor (involuntary, rhythmic shaking of a limb; the head, mouth, or
tongue; or the entire body).
Parkinson's disease has no known cause or cure. Symptoms arise when a
small region of the brain called the substantia nigra, degenerates. As
neurons (brain cells) in this region die, the brain becomes deprived of
the chemical dopamine, a neurotransmitter that enables communication
among brain cells involved in motor control. Reduced levels of dopamine
lead to symptoms of Parkinson's disease. As it progresses, Parkinson's
disease becomes increasingly disabling, making routine daily activities
like bathing, dressing, and eating difficult or impossible without
Introduced more than 30 years ago, the drug levodopa remains the gold
standard for the initial treatment of Parkinson's disease. After about
five to seven years, however, treatment with levodopa typically causes
motor complications such as dyskinesia and fluctuations in motor control
that can lead to intolerable disability in many patients.
Activa DBS Therapy reduces some of the motor symptoms of advanced
Parkinson's disease and the motor complications associated with levodopa
by modulating abnormal neuronal activity in the brain's movement center.
It involves the implantation of a medical device — the Kinetra or
Soletra neurostimulation system — that delivers electrical pulses to
precisely targeted areas of the brain involved in motor control. The
stimulation can be adjusted non-invasively as the disease progresses to
meet changing patient needs.
More than 30,000 people worldwide have received Activa DBS Therapy,
which is approved for the treatment of the three most common movement
disorders — Parkinson's disease, essential tremor, and dystonia.