Surgery helps symptoms of Parkinson’s disease
By Kathy Oxtoby
A type of surgery for people with Parkinson’s disease - called deep brain stimulation - helps to reduce symptoms for at least three years, a new study has found.
Parkinson's disease affects how you move. It happens when your brain stops making enough of a chemical called dopamine. Brain cells need this chemical to send messages around your brain, and to nerves and muscles throughout your body. With less dopamine, you can't control your movements in the usual way. For example, your hands may shake or your movements may become stiff and slow.
Parkinson’s disease is mainly treated with drugs. These tend to clear up your symptoms for a while. But drugs for Parkinson’s disease can stop working after several years, and they can cause unpleasant side effects that may be permanent.
Surgery is another way of helping some people in the later stages of Parkinson's disease. One type of surgery is called pallidal deep brain stimulation. This is an operation that temporarily stuns some of the cells in the part of the brain known as the globus pallidus. Another type of surgery is called subthalamic deep brain stimulation. This temporarily stuns cells in a part of your brain known as the subthalamic nucleus.
Both these types of surgery aim to reduce the symptoms of Parkinson's and the side effects that drugs can cause after some time.
Studies looking at these operations have only been done over a short period of time. But we need longer studies to know if they work for longer.
This study included 89 people who had pallidal deep brain stimulation and 70 who had subthalamic deep brain stimulation. After their operation, people took tests every few months to measure how well they were able to move around. The researchers then compared whether surgery improved people’s movements, and how long the effect lasted.
Pallidal deep brain stimulation seemed to work as well as subthalamic deep brain stimulation After three years, people were still able to move around more, and more easily, than before they had surgery.
Although people said that their quality of life improved after the first six months, by the end of the study their quality of life fell slightly. People also performed slightly less well on cognitive and thinking tests.
This is the first time a good-quality study has compared these two types of surgery over a long-term period to see which works best.
But this is a small study, and smaller studies are less reliable than larger ones.
Also, there may be other reasons why people’s quality of life fell after the first six months. Parkinson’s disease gets worse over time. It may be that people’s quality of life fell because their illness was becoming worse. We can’t be sure the fall in quality of life is because the operation stops working, or because the disease is getting worse.
Drugs help slow down Parkinson’s disease. But it will eventually get worse, and drugs might not work as well when this happens. At this stage, surgery may be an option. People who have this type of surgery are at risk of having a stroke, headaches, and problems with talking and vision. For this reason, your doctor will probably suggest this operation only if you're in the later stages of Parkinson's disease. Before you decide to have surgery, you should talk to your surgeon about your risk of problems.
Weaver F, Follett K, Stern M, et al. Randomized trial of deep brain stimulation for Parkinson disease. Thirty-six-month outcomes. Neurology. Published online 21 June 2012.