As the development of new medications for Alzheimer’s disease stalls, researchers are turning to deep brain stimulation as a possible way to help people with this disease continue to live independently.
This treatment, which involves stimulating the brain through small, implanted wires, has been used successfully in thousands of people worldwide with other neurological conditions, such as Parkinson’s.
Now researchers are testing to see whether it might benefit people with Alzheimer’s and take some of the weight off caregivers’ shoulders.
In a new study, researchers surgically implanted thin electrical wires in the brains of three people with mild Alzheimer’s disease. Each wire was connected to a pulse generator in the chest wall.
The device continuously stimulated the frontal lobe in the brain, similar to how a cardiac pacemaker stimulates the heart. The goal of this deep brain stimulation was to slow the progression of Alzheimer’s disease.
This was a pilot study, with a small number of participants, so experts say the results should be viewed with caution.
However, Dr. Douglas Scharre, co-author of the study and director of the Division of Cognitive Neurology at the Ohio State University’s Wexner Medical Center’s Neurological Institute, told Healthline that he was pleased with the results.
“People tolerated the procedure very well,” said Scharre.
There were also signs that the treatment may be of “potential benefit” to patients and caregivers.
After at least 18 months of continuous deep brain stimulation, all three people showed signs of improvement in their executive function. That includes mental abilities such as problem-solving, decision-making, planning, organization, attention, and focus.
However, when researchers compared these three people to similar people who didn’t undergo treatment, only two of the three had “statistically significant” improvements.
Scharre said the last person, a female, was very young and had genetic markers linked to a faster decline in Alzheimer’s.
Deep brain stimulation is thought to affect the activity and interaction of neurons.
In previous studies, said Gwenn Smith, PhD, a professor of psychiatry and behavioral sciences at Johns Hopkins Medicine in Maryland, “deep brain stimulation not only increased brain metabolism in specific regions, but also increased the connections between them, what’s known as ‘functional connectivity.’”
These both decrease over the course of Alzheimer’s disease.
The new study was published today in the Journal of Alzheimer’s Disease.
Targeting everyday skills
This is not the first study of deep brain stimulation as a potential treatment for Alzheimer’s disease.
Previous deep brain stimulation studies in people with Alzheimer’s disease focused on the memory circuits.
The current study, though, is the first to target non-memory circuits of the brain.
“The researchers looked at a new target, and have found some increase in brain metabolism and some stability of cognition,” Smith said.
Smith was part of an earlier study that used deep brain stimulation on the memory circuits in Alzheimer’s patients.
There may be other benefits of deep brain stimulation besides improved mental abilities.
“What’s also interesting about the target in this study is that there may be potential for an improvement of some neuropsychiatric symptoms,” Smith told Healthline.
These other symptoms include depression, which is common among people with Alzheimer’s.
Other studies have used deep brain stimulation of the frontal lobe in people with major depression.
Scharre said one reason they chose the frontal lobe is because doctors currently don’t “have a lot of ways to help with those symptoms in Alzheimer’s patients.”
Most treatments and medications for Alzheimer’s disease focus on improving the memory.
There are also many ways that caregivers can help people cope with memory loss — such as using calendars, notes, alarms and reminders.
It’s more difficult, though, to compensate when a person is no longer able to do things like run an errand or go on an outing. These activities require people to plan and make many decisions, such as where they’re going, what the weather is like, which clothes to wear, and how much money to bring.
“These other areas of cognition are really important for day-to-day functioning and caregiving,” said Scharre.
Interest in deep brain stimulation
More studies are needed to confirm that deep brain stimulation of the frontal lobes is safe and effective in people with Alzheimer’s disease.
Scharre said the next step is to apply for grants to fund a larger trial. He thinks a multi-center trial will be needed to get enough patients.
If larger clinical trials show that deep brain stimulation is safe and works for people with Alzheimer’s disease, it may not be the one-cure-fits-all that some people imagine.
“Deep brain stimulation is not for all Alzheimer’s patients,” said Scharre. “There’s a sub-population that may benefit from this, and others that may not.”
All three patients in the current study had mild Alzheimer’s. People whose disease is more advanced may not benefit as much because the neurons may not respond the same to stimulation.
Deep brain stimulation may not be a cure for Alzheimer’s, but it may slow the worsening of symptoms. This could translate to a big improvement in everyday functioning.
In many studies of Alzheimer’s disease, “showing the safety of deep brain stimulation and the stability of mental function is encouraging,” said Smith.
Scharre also thinks that if deep brain stimulation is approved by the U.S. Food and Drug Administration for Alzheimer’s disease, it will be one of several treatments for doctors to choose from.
This is similar to how doctors treat high blood pressure, high cholesterol, diabetes, and other conditions. Not every medication or treatment works equally well for all patients.
Since there hasn’t been a new Alzheimer’s drug in more than 10 years and little research into Alzheimer’s is being done by drug companies, this potential new treatment offers hope to the field.
“We have found that there has been a lot of interest in deep brain stimulation among Alzheimer’s doctors and patients,” said Smith.
She added that one of the reasons for the “sustained interest” is that studies continue to show that it is safe.
But Scharre is careful to temper this interest with the reality of where the research stands right now.
“Patients shouldn’t be running to their neurosurgeon to get these things put in their brain,” said Scharre. “It’s still a work in progress.”