December 2, 2014
Surgeons are testing a procedure called deep brain stimulation for people in the early stages of Alzheimer’s disease. The technique, which acts like a pacemaker for the brain, has shown promise in easing the movement problems and other symptoms of Parkinson’s disease. Doctors hope it may offer advantages for enhancing memory and thinking skills in those with Alzheimer’s.
The technique involves implanting a metal device under the shoulder blade, with wires leading deep into the brain. Small streams of electricity activate parts of the brain critical for thinking and memory.
Early tests in Canada have shown promise. Implantation of the pacemaker-like device resulted in greater usage of blood sugar, or glucose, in parts of the brain involved in memory processing. Greater activity in these areas is correlated with enhanced thinking and memory skills and a better quality of life. With Alzheimer’s, glucose usage in these brain areas typically diminish as the disease progresses.
The tests of the procedure are beginning in the United States. “Recent failures in Alzheimer’s disease trials using drugs such as those designed to reduce the buildup of beta-amyloid plaques in the brain have sharpened the need for alternative strategies,” said Dr. Paul B. Rosenberg of Johns Hopkins Medical Center, where the first surgeries were performed in late 2012. “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 for a disease becoming all the more common with the aging of the population.”
As part of the federally-funded study, about 40 patients are expected to receive the deep brain stimulation implant over the next year or so at various medical centers in the United States and Canada. In addition to Johns Hopkins, they include the University of Pennsylvania, Ohio State University, the University Health Network in Toronto, and the Banner Alzheimer’s Institute in Arizona. Other small studies are being conducted in Europe and Israel.
The surgery has been performed in more than 80,000 people with Parkinson’s disease over the past 15 years, with many patients reporting fewer tremors and the need to take less medication. In those cases, side effects have been uncommon, occurring in 0.4 to 6 percent of patients. Deep brain stimulation is also being tested for severe depression and other psychiatric conditions.
The current research will be assessing safety in people with Alzheimer’s. Only patients with mild Alzheimer’s who can decide on their own to participate will be included in the trial.
The surgery requires that tiny holes be drilled into the skull to implant wires into the fornix, a part of the brain that sends signals to memory centers like the hippocampus. The hippocampus is among the earliest brain areas to be affected by Alzheimer’s. The wires are attached to the pacemaker-like device in the shoulder, which delivers 130 miniscule electrical pulses to the brain each second. Patients do not feel the electrical current.
For the trial, all of the patients will receive a brain pacemaker. 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.
Results are not expected for a year or more. But “deep brain stimulation might prove to be a useful mechanism for treating Alzheimer’s disease, or it might help us develop less invasive treatments based on the same mechanism,” Dr. Rosenberg said.
Sources: Johns Hopkins Medical Center. For more information on the trials, see ClinicalTrials.gov, http://www.clinicaltrials.gov/ct2/results?term=alzheimer+deep+brain+&Search=Search