Data from a five-year clinical trial is adding to growing evidence that deep brain stimulation (DBS) can slow the ravages of Parkinson's disease.
Researchers at Vanderbilt University Medical Center in Nashville, Tenn., said that the therapy appears to curb any worsening of tremor and other symptoms, as well as lessening a patient's need for medications.
"Parkinson's is relentless," senior study author Dr. David Charles, Vanderbilt professor and vice-chair of neurology, said in a medical center news release. "There's nothing that slows down its progression."
However, "with this pilot study, we've shown that if DBS is implanted early it's likely to decrease the risk of progression, and if this is borne out in our larger study it would be a landmark achievement in the field of Parkinson's disease," he said.
The new study was small -- just 30 patients. Between 2006 and 2009, the participants were randomly selected to receive either the optimal Parkinson's disease drug therapy, or optimal drug therapy plus DBS.
In DBS, doctors surgically implant a pair of ultra-thin electrodes deep into the brain. The electrodes target electric pulses to the subthalamic nucleus, a small cluster of neurons. Similar to a heart pacemaker, the device is powered by a small battery implanted under the skin near the patient's collarbone.
After five years, patients who'd received only the drug therapy had a five times higher risk of progression of "rest tremor" -- a key Parkinson's symptom -- compared to those patients who'd gotten the electrode implants as well as drug therapy, the researchers reported.
What's more, patients who got DBS needed far fewer meds going forward.
"Patients who were randomized to receive early optimal drug therapy [only] had 15-fold greater odds of needing multiple types of Parkinson's disease medications," study project leader Mallory Hacker, an assistant professor of neurology at the medical center, said in the news release.
The evidence of reductions in another key Parkinson's symptom -- worsening motor symptoms -- did not reach statistical significance, the researchers said, although there was a trend suggesting a benefit from DBS.
Still, this study was small and the results should be considered preliminary, Charles said.
"While this is an incredibly exciting finding, patients and physicians should not change clinical practice at this time," Charles said. "What this pilot study is most clearly telling us is that the new FDA-approved Phase III study must be done to definitively determine whether DBS slows the progress of Parkinson's disease when implanted in the very earliest stages."
Dr. David Weintraub directs functional neurosurgery at North Shore University Hospital in Manhasset, N.Y. Reading over the study he said that it "provides evidence that the use of DBS surgery early in the course of Parkinson's disease can have meaningful benefits for patients compared to medication alone."
Weintraub agreed that the findings remain preliminary. However, he said that positive results from a "larger scale, multicenter trial could potentially lead to the adoption of DBS surgery even earlier in the course of Parkinson's disease treatment, which would be a very significant advance in the field."
The study was published in the July issue of Neurology. It received funding from the U.S. National Institutes of Health, the Michael J. Fox Foundation for Parkinson's Research, and Medtronic, Inc., the manufacturer of the DBS system used in the trial.
Visit the Parkinson's Foundation for more on Parkinson's disease.