Oct. 15, 2010 -- More than 50 experts on the use of deep brain stimulation for treatment of tremors and other symptoms of Parkinson’s disease have reached general agreement on when the surgical procedure should be considered and which patients might reap most benefits, a new report says.

The report, published in the online edition of Archives of Neurology, says the best candidates for deep brain stimulation are those who can’t tolerate the side effects of medication and those who don’t suffer from significant active cognitive or psychiatric problems but who do suffer from tremors or motor skills control.

In a deep brain stimulation procedure, a neurosurgeon surgically implants a neurostimulator in the brain in the location where abnormal electrical nerve signals generate the tremors and other symptoms common in Parkinson’s patients. The neurostimulator generates electric stimulation to the area to block the signals.

The report also says that:

    * Deep brain stimulation surgery is best performed by an experienced team and neurosurgeon who have expertise in stereotactic neurosurgery -- microsurgery deep within the brain that is based on a three-dimensional coordinate system using advanced neuroimaging.
    * Deep brain stimulation is effective when used in the two most commonly treated areas of the brain, called the subthalamic nuclei and the globus pallidus pars interna. But treatment in the subthalamic nuclei may cause increased depression and other symptoms in some patients.
    * Surgical removal of the area of the brain that causes Parkinson’s disease is an effective alternative and should be considered as an alternative in some people.
    * Surgical complication rates vary, with infection being the mostly commonly reported side effect of deep brain stimulation.

Making an Informed Decision

“We know that very little accessible information is out there to help a Parkinson’s patient make an informed decision as to whether he or she would be a good candidate for deep brain stimulation,” says report lead author Jeff Bronstein, MD, PhD, a professor of neurology at University of California, Los Angeles, in a news release.

Surgical studies take a long time, and what’s known about deep brain stimulation is focused, limited, and often written by one group, reflecting their opinions and biases, he says.

Bronstein says the results of a meeting in April 2009 of the Parkinson’s experts are intended to clarify some issues about the use of deep brain stimulation.

The FDA approved deep brain stimulation as a treatment for Parkinson’s disease in 2002, and since then more than 70,000 people have undergone the procedure. The authors write than more than 30% of failures of deep brain stimulation have been due to “inappropriate indications for surgery.”

The report says long-term improvements have been shown for up to five years for a number of Parkinson’s disease symptoms.

The experts caution that Parkinson’s disease continues to progress after deep brain stimulation.

Sixteen of the researchers disclosed receiving compensation from Medtronic Inc., a manufacturer of the device used in deep brain stimulation procedures. Others reported financial support from pharmaceutical companies for consultations or for speaking fees.