Sunday, May 5, 2013

First Brain Pacemaker to Slow Alzheimer’s Effects

Scientists at the Ohio State University Wexner Medical Center have begun a trial to test whether or not a deep brain stimulation device – a “brain pacemaker” – can ward off the debilitating symptoms of Alzheimer’s disease. Their first patient, 57-year-old Kathy Sanford, received the implants last October 2012. Prior to the surgery Sanford had been diagnosed with mild Alzheimer’s, and her symptoms were progressively getting worse. But after five months of continuous stimulation from the brain pacemaker her performance on cognitive tests has vastly improved. It’s still too early to know if the effects will last, but the doctors are hopeful.

Image and video hosting by TinyPic

The study is led by Dr. Douglas Scharre, a neurologist and director of the division of cognitive neurology, and Dr. Ali Rezai, a neurosurgeon and director of the neuroscience program.

This Food and Drug Administration-approved study is researching whether the use of a brain pacemaker can improve the cognitive and behavioral functions in patients with mild or early-stage Alzheimer’s, a degenerative brain disease that has no cure.

“Our hope is that this deep brain simulation is going to help stimulate the brain to make it work better,” Scharre said.

“Basically, the pacemakers send tiny signals into the brain that regulate the abnormal activity of the brain and normalize it more,” Dr. Ali Rezai, a neurosurgeon and co-leader of the study said in a press release. “Right now, from what we’re seeing in our first patient, I think the results are encouraging, but this is research. We need to do more research to understand what’s going on.”

Image and video hosting by TinyPic

The disease damages many of the brain’s networks, explained Dr. David Wolk, an assistant professor of neurology at the Perelman School of Medicine at the University of Pennsylvania and assistant director of the Penn Memory Center in Philadelphia. Wolk’s group is just starting to screen patients for a trial similar to the one at Ohio State, although the Penn researchers plan to stimulate a different area of the brain.

“The most prominent circuit involved in the disease is the one for memory,” Wolk said. “It’s thought that if we can stimulate that network we can make it perform more effectively.”

Wolk also claims that there's data showing that deep brain stimulation might actually promote neuronal growth. "One of the few areas that that is capable of producing new neurons as we get older is the hippocampus," says Wolk.

And that’s very important since the hippocampus, which is intimately involved in laying down new memories, is one of the brain regions that is hardest hit by Alzheimer’s disease.

Unlike the Enterprise where all procedures seem to involve a few simple scans on an outpatient basis, implanting the brain pacemaker is major surgery. Two stimulating electrodes are inserted through holes drilled into the skull. A battery pack, implanted beneath the skin near the collarbone, powers the electrodes via wires that run up the neck and beneath the scalp.

The brain pacemaker works similarly to a cardiac pacemaker device but has wires connected to the brain rather than the heart. The pacemaker sends tiny signals that regulate brain activity. Sanford returns for a checkup each week where she completes a series of activities, and she and her family answer questions about her behavioral tendencies. From there, adjustments are made to the pacemaker to send signals to different areas of the brain.

So far doctors haven’t reported any adverse side effects from Sanford’s treatment. The trial is scheduled to conclude in 2015, by which time up to ten Alzheimer’s patients will have received the brain pacemaker.

Image and video hosting by TinyPic

Deep brain stimulation (DBS) is already widely used to alleviate the symptoms of Parkinson’s disease and other disorders that interfere with movement. Implanting electrodes into the brain isn't new.
Between 85,000 and 100,000 people around the world have had DBS to block the tremors of Parkinson's disease and other movement disorders. The continuous jolts quiet overactive nerve cells, with few side effects. Scientists also are testing whether stimulating other parts of the brain might help lift depression or curb appetite among the obese. However, Sanford is the first person to receive a permanent implant for Alzheimer’s, according to the surgical team. Dr. Rezai says the brain pacemaker could also one day help alleviate symptoms of other chronic brain disorders such as obsessive compulsive disorder, depression, chronic pain, and migraines.

Image and video hosting by TinyPic

The current study continues the work begun by Dr. Andres Lozano who, in 2003, serendipitously discovered the potential DBS held for Alzheimer’s patients. At the time he was treating a patient with obesity. By stimulating the fornix, a major nerve tract of the brain that connects to the hypothalamus, a key regulator of appetite, Dr. Lozano thought normalizing its activity through electrical shocks would suppress the patient’s appetite. But the fornix also connects to the hippocampus, the memory center of the brain. Unexpectedly, the stimulation caused the patient’s memory to improve.

Last May Dr. Lozano was involved in a phase I study to test the safety of DBS as a treatment for Alzheimer’s disease. One hallmark of Alzheimer’s disease is the decreased activity of neurons in affected brain areas such as the hippocampus and other areas of the temporal lobe. Because they aren’t working as much, these neurons also show a decrease in metabolic activity, measured by dropping levels of glucose metabolism. The study showed a metabolic increase: 15 to 20 percent over the course of a year of stimulation. The increase is greater than that which normally results from drug treatments. More importantly, the patients showed improvements in memory, cognitive abilities, and quality of life overall.

“I think it’s reasonable to try deep brain stimulation for Alzheimer’s,” said Dr. Mark Richardson, an expert not affiliated with any of the new trials and director of epilepsy and functional neurosurgery at the University of Pittsburgh Medical Center. “But one thing that’s important to realize is that just as in Parkinson’s disease, there’s no evidence that this slows down or treats the actual cause of the disease. But it may improve symptoms just like it does for Parkinson’s.

Sourceс and Additional Information:

Related Posts Plugin for WordPress, Blogger...