A study, released Tuesday by the Journal of the American Medical Association reported that patients with advanced Parkinson's disease had a better response to a pacemaker like devise implanted in the brain than drugs and therapy did.

The study is one of the first to measure and compare conventional drug treatment versus deep brain stimulation in patients suffering from Parkinson's disease. Parkinson's tends to affect older people and medication has been the conventional treatment though not all the patients respond to medication and these also tend to lose their effectiveness with time resulting in increased side effects of hand tremors, jerky movements etc.

Deep brain stimulation devises have been used for the last decade or so by doctors to treat patients with Parkinson's whereby electrodes are used to deliver electrical impulses to the substantia nigra, a crescent-shaped region in the center of the brain that controls and coordinates movement.

A pacemaker like device is implanted in the chest and wires are planted deep into the patient's brain where energy is used to stimulate areas linked to movement issues. The researchers said this devise is also linked to a greater risk of problems, such as infection, because of the complicated surgery.

"It definitely is brain surgery and that should give anyone pause," says David Charles, M. D., of Vanderbilt University, in Nashville, Tennessee, who was not involved in the new study. He however did go on to add that most of the problems seen in the study were related to the surgery itself, and many had resolved themselves within six months.

The study was led by Frances Weaver, Ph. D., director of the Center for Management of Complex Chronic Care at the Hines VA Hospital, in Hines, Illinois, and he and his colleagues studied 255 Parkinson's patients enrolled at 13 different hospitals.

The researchers divided them into two groups on random and one group got the device implanted in one of two different areas of the brain. The second group of patients was treated with the best-available medical therapy, including drugs and physical therapy.

After six months both the groups were studied and the researchers found that the group with the implant reported 4.6 hours a day more of "on" time while the control group showed no improvement in "on" time whatsoever. "On" time is time when the patient is free of movement problems. . Over all, 71 % of the deep brain stimulation patients had better motor function, compared to 32 % of the medical therapy patients and scored significantly better on a quality-of-life measure.

"It's huge, and more than that, it's consistent with what other studies are finding too," says Charles. "It's a large study at multiple centers with lots of patients and it's done in a very rigorous manner."

The drawback was seen in the matter of side effects which were 40% in the implant group versus 11 % in patients on drugs. Common complications included infections at the surgical site, often where the power generator is implanted in the chest and reports of psychiatric disorders and a higher rate of falls.

Weaver said the falls could be attributed to the fact that feeling much better the patients tended to physically overdo things. Anyone keen on the implant should keep in mind the risks and take their doctor's advise. "You really have to consider the risks and the benefits" of this therapy for each patient, she said.

The study was financially backed by the Department of Veterans Affairs, the National Institute of Neurological Disorders and Stroke and Medtronic.