Over the past decade a kind of brain surgery known as deep-brain stimulation (DBS) has helped some Parkinson's disease sufferers develop better control of their physical movements. But the risks that come with the invasive procedure—not to mention the costs—keep physicians and patients cautious. The treatment is usually indicated when medicine no longer addresses the neurodegenerative disorder's symptoms effectively. Now, a new study from European researchers indicates that deep-brain stimulation's benefits are just as promising for people in the earlier stages of Parkinson's.
"The conclusions of this study are really exciting," says David Charles, the chief medical officer of the Vanderbilt Neuroscience Institute and director of the movement disorders clinic there. "Most likely it will be a transformative study in our understanding of when to apply deep-brain stimulation therapy in Parkinson's disease."
Parkinson's disease is a disorder of progressive decline. The tremors, rigidity and difficulty moving are often treated with anti-Parkinson's medications such as levodopa at first. But as the disease marches forward, the benefits fall off. The same dose no longer lasts as long, patients experience unpredictable cycles in their ability to move, and struggle with excessive movements called dyskinesias that make their limbs jump and flail involuntarily. This stage of the disease, which many people reach in their mid-60s, is when some decide to undergo DBS.
Researchers at several French and German institutions enrolled 251 people with midstage Parkinson's disease in a multicenter trial to see if DBS was helpful for individuals in earlier stages of Parkinson's. On average the study participants had been living with the disorder for 7.5 years and were 52 years old—younger and earlier in their disease progression than is typical for those undergoing DBS. Quality of life was assessed by a standard 39-question survey that included questions about well-being, discomfort, mobility and daily life activities. For example, the survey asked how often study subjects had difficulty carrying shopping bags, whether they had problems walking half a mile or 100 yards or whether they felt frightened or worried about falling over in public.
Participants reported a 26 percent improvement in quality of life after receiving deep-brain stimulation and medication for two years. They slept better, which gave them the energy to cope with more stressful situations, says one of the study's co-authors, Günther Deuschl, a professor of neurology at Christian-Albrechts University of Kiel in Germany. Also, instead of having to deal with unpredictable periods of immobility, people were able to make appointments and schedule social activities, he adds. A parallel group that received only standard medical therapy reported a 1 percent decrease in quality of life. In addition, participants in the experimental group reported better mobility, which was backed up by video assessments. The results are published in the February 14 issue of The New England Journal of Medicine.
The study demonstrates that DBS combined with medicine is better than the latter alone when the procedure takes place at an early stage of Parkinson's, Charles says, adding, "It's not as if it was a little bit better. The numbers on quality of life and motor performance were dramatic." He was not involved in the new study but is conducting a U.S.-based pilot study to examine the effects of DBS on subjects in the early stages of Parkinson's.