In the US, surgeons implant the first brain 'pacemaker' for Alzheimer's disease
6th December 2012
Researchers at Johns Hopkins Medicine in the US have surgically implanted a pacemaker-like device into the brain of a patient in the early stages of Alzheimer's, the first such operation in the United States.
The device, which provides deep brain stimulation and has already been used in thousands of people with Parkinson’s disease, is seen as a possible means of boosting memory and reversing cognitive decline.
The surgery is part of a federally funded, multicenter clinical trial marking a new direction in clinical research designed to slow or halt the ravages of the disease, which slowly robs its mostly elderly victims of a lifetime of memories and the ability to perform the simplest of daily tasks, researchers at Johns Hopkins say. Instead of focusing on drug treatments, many of which have failed in recent clinical trials, the research focuses on the use of low-voltage electrical charges delivered directly to the brain. There is currently no cure for Alzheimer’s disease.
As part of a preliminary safety study in 2010, the devices were implanted in six patients with Alzheimer’s disease in Canada. Researchers found that patients with mild forms of the disorder showed sustained increases in glucose metabolism, an indicator of neuronal activity, over a 13-month period. Most Alzheimer’s disease patients show decreases in glucose metabolism over the same period.
The first U.S. patient in the new trial underwent surgery at the Johns Hopkins Hospital, and a second patient is scheduled for the same procedure this month.
Paul B. Rosenberg, M.D., an associate professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, and site director of the trial’s location: "This is a very different approach, whereby we are trying to enhance the function of the brain mechanically. It’s a whole new avenue for potential treatment of a disease becoming all the more common with the aging of the population."
Some 40 patients are expected to receive the deep brain stimulation implant over the next year at Johns Hopkins and four other institutions in North America. Only patients whose cognitive impairment is mild enough that they can decide on their own to participate will be included in the trial.
While experimental for Alzheimer’s, over 80,000 people with Parkinson’s have undergone the procedure over the past 15 years, with many reporting fewer tremors and requiring lower doses of medication afterward. Researchers are testing deep brain stimulation for other conditions – for example, to control depression and obsessive-compulsive disorder resistant to conventional therapies.
The surgery involves drilling holes into the skull to implant wires into the fornix on either side of the brain. The fornix is a brain pathway instrumental in bringing information to the hippocampus, the portion of the brain where learning begins and memories are made, and where the earliest symptoms of Alzheimer’s appear to arise. The wires are attached to a pacemaker-like device, the "stimulator," which generates tiny electrical impulses into the brain 130 times a second. The patients don’t feel the current, Rosenberg says.
For the trial, all of the patients will be implanted with the devices. Half will have their stimulators turned on two weeks after surgery, while the other half will have their stimulators turned on after one year. Neither the patients nor the doctors treating them will know which group gets an early or later start.
"Deep brain stimulation might prove to be a useful mechanism for treating Alzheimer’s – or it might help us develop less invasive treatments based on the same mechanism," Rosenberg says.
By 2050, the number of people in the US aged 65 and older with Alzheimer’s may triple, experts say, from 5.2 million to 16 million, unless effective treatments are found.