Patients with advanced Parkinson's disease can have a better quality of life and improved mobility if they undergo deep brain stimulation surgery along with standard medications for the condition, new research finds.

The authors of the study, published in The Lancet Neurology, caution, though, that there are serious risks from the surgery. Nevertheless, they conclude that the surgery "is an important treatment option" that should be offered to patients with advanced disease.

Researchers from the University of Birmingham examined the effects of deep brain stimulation on the lives of people with advanced Parkinson's disease using a randomized trial.

Of 366 patients, they asked half to take the standard Parkinson's drug treatments, and the other half to take the medications as well as undergo deep brain stimulation.

In the surgery, electrical impulses were delivered in the basal ganglia, an area deep in the brain that controls movement.

A year after treatment, the patients then completed questionnaires to score their quality of life, functioning and cognitive status, using standard customized questionnaires.

The researchers found that those who underwent deep brain stimulation reported their quality of life improved by five points, compared to the medication-alone group whose score improved by only 0.3 points.

The surgery group also experienced:

• an 8.9-point improvements in mobility
• a 12.4-point improvement in activities of daily living
• a 7.5-point improvement in bodily discomfort

Surgery also reduced problems with uncontrolled movements, called dyskinesia, and "off time," when motor symptoms are not adequately controlled.

But there were risks associated with the surgery: 36 patients (or 19 per cent) had 43 surgery-related serious adverse events, the most common being infection. One patient died as a result of the procedure.

As well, 20 surgery patients and 13 medical therapy patients experienced serious adverse events related to the drug treatment, the most common of which was worsening of Parkinson's symptoms or uncontrolled symptoms.

The authors conclude: "Surgery is likely to remain an important treatment option for patients with [Parkinson's disease], especially if the way in which deep brain stimulation exerts its therapeutic benefits is better understood, if its use can be optimised by better electrode placement and settings, and if patients who would have the greatest benefit can be better identified."