Deep brain stimulation shows promise in treating Alzheimer’s
Published: Wednesday, December 12, 2012 at 12:07 p.m.
Last Modified: Wednesday, December 12, 2012 at 12:07 p.m.
Dr. Kelly Foote, a neurosurgeon at the University of Florida and Shands, has started giving people a different answer when they ask him if deep brain stimulation could benefit Alzheimer’s disease patients. Now he says “maybe,” instead of a flat-out “no.”
Foote’s revised opinion is based on potentially compelling evidence: Last week, his colleagues at Johns Hopkins performed the first DBS procedure in an Alzheimer’s patient, as part of a multicenter clinical trial in which UF is participating.
“What we’re doing is fundamentally exciting,” Foote said, adding that using DBS in Alzheimer’s patients opens the door to using it in patients with other neuro-degenerative disorders caused in part by the atrophy, or shrinkage, of a neural network inside the brain.
With Alzheimer’s, patients’ hippocampus, the memory and learning center, gets smaller as the metabolic activity controlling its circuitry declines.
DBS appears to increase the metabolic activity of that circuitry. A preliminary study of 6 patients who underwent the procedure in Canada showed promising results in 2010. Scientists discovered the potential for DBS in Alzheimer’s accidentally: Researchers thought they could treat morbid obesity by stimulating the brain’s hunger center, which is also located in the hippocampus. That didn’t work, but the patient on whom they tried described vivid memories from his past when his brain was stimulated.
DBS as a procedure is not new: Doctors have used it to treat patients with Parkinson’s disease, dystonia, obsessive compulsive disorder and even depression -- and Foote and neurologist Michael Okun, the directors of UF’s Center for Movement Disorders and Neurorestoration, have been at the forefront of those advances.
The way DBS works is that doctors drill a hole in the skull and then place a lead that delivers electric current to the part of the brain they want to stimulate -- in this case, the fornix, a bundle of neurons that carries signals to and from the hippocampus. Doctors then place a pulse generator below the patient’s clavicle programmed to deliver the electric current to the brain through the lead.
Okun is the principal investigator for the UF portion of the trial that includes researchers from the University of Pennsylvania, the Banner Health System in Phoenix, and Johns Hopkins. “The reason DBS may actually be viable is that these brain circuits aren’t completely gone … there is still a lot of connectivity,” Okun said. “If you can restore the neural network, there’s a potential at least to give someone memory function for a few years.”
To benefit from DBS, patients have to be newly diagnosed -- before the disease has done too much damage. Okun is also careful to point out that DBS is not a cure for the disease but could treat symptoms. And that’s encouraging, since until now, there has been very little for Alzheimer’s patients.
“People have tried vaccines, gene therapy approaches … everything that’s been brought forward has not panned out in humans as it has in animals,” Okun said, adding that the drugs that have been tested for treating Alzheimer’s have been equally disappointing.
An estimated 5 million Americans currently have Alzheimer’s, a number that is predicted to jump to 13 million by 2050.
Okun and Foote will do their first DBS procedure in an Alzheimer’s patient in January. A total of 40 patients will be enrolled in the trial across all centers. It is a prospective, randomized, double-blinded, placebo-controlled trial, meaning that some patients will have the pulse generator turned on within two weeks of having it implanted, and some will have it turned on a year later -- and neither the patients nor the examining doctors will know which patients have it turned on right away and which patients wait.
“I understand that might give people some pause,” Foote said. “Most people would still theoretically benefit from it because (the pulse generator) would eventually turn on, and the evidence would be more solid at that point.”
Contact Kristine Crane at 338-3119 or firstname.lastname@example.org.