How effective is deep brain stimulation for treating Parkinson's disease?

Deep brain stimulation is a surgical procedure which has been shown to be effective in improving dyskinesia (uncoordinated or jerky movements) and tremor in Parkinson’s disease.  The procedure itself involves implanting an electrode into the areas of the brain that help direct movement.  This therapy is typically used in patients with advanced disease who are inadequately controlled with medications or unresponsive to medications.  Rare risks of the procedure include bleeding in the brain, stroke, and infection.

Deep brain stimulation of the thalamus is effective in reducing tremor. It does not affect slow movement (bradykinesia), stiffness (rigidity), or other symptoms.

Deep brain stimulation of the subthalamic nucleus:

• Reduces tremor and, to a lesser extent, other symptoms of Parkinson's disease. Deep brain stimulation tends to have the greatest effect on tremor. But slow movement and stiffness can also be reduced, and gait can be improved.
• Reduces the on-off motor fluctuations associated with long-term use of levodopa. During the course of a day, you may have "on" periods when the levodopa controls Parkinson's symptoms and "off" periods when the medicine stops working. Deep brain stimulation can reduce the length and severity of "off" periods.
• Reduces the abnormal movements (dyskinesias) that are side effects of levodopa therapy.

There is not enough evidence to say how well deep brain stimulation of the thalamus or globus pallidus works to control motor complications or improve motor symptoms in Parkinson's disease.