Devices that transmit continuous electrical impulses are well known to people fitted with pacemakers, and to patients with Parkinson’s disease for whom such gadgets help reduce tremors.
There is no similar device to benefit Alzheimer’s patients. That’s not my news today.
But scientists do believe they’ve found a novel technique that will help them. It involves placing thin-as-a-hair electrodes into the brain to activate areas that degenerate because of this disease.
It’s called intermittent electrical brain stimulation. Here’s how it works.
Improved Memory When Patients Felt Low
Intermittent stimulation involves a repeated series of electrical impulses followed by a period of relaxation.
Previous attempts to do this gave mixed results, but earlier this year a trial involving 150 epilepsy patients showed for the first time that the timing of the stimulation was critical.
The participants performed 12-13% better on memory tests if the stimulation occurred when they were feeling groggy or down in the dumps, but 15-20% worse than usual if they received the treatment when they were feeling upbeat.
Dr. Michael Kahana of the University of Pennsylvania led the research team drawn from ten different institutions. He reports, “We found that jostling the system when it’s in a low-functioning state can jump it to a high-functioning one.”
Commenting on the research, Dr. Bradley Voytek, assistant professor of cognitive science at the University of California, said, ” …the era of dumb stimulators is over…[this] gives us a blueprint for moving forward.”
Test Subjects Remembered Things Five Times Longer
In the most recent study, published in Current Biology in September, a research team from Medical College of Georgia, Augusta University, placed electrodes in the brains of monkeys to increase the activity of an area of the forebrain called the nucleus basalis of Meynert. This region degenerates as Alzheimer’s disease progresses.
They then use a standard memory test to evaluate the monkeys’ working memory — the kind needed every day for learning new information, following instructions and planning actions.
When they applied continuous stimulation they saw a decline in memory, but with intermittent stimulation the primates could recall information up to five times longer.
After months of such stimulation, they became more proficient at the test even when electrical impulses weren’t applied.
Neuroscientist David Blake, who led the study, said those that were poor performers at the beginning rose to average; those that were middle-of-the-pack climbed to the top of the class.
Increases Acetylcholine
The optimal benefit came at 60 pulses per second for 20 seconds followed by an interval of 40 seconds.
The scientists found that intermittent stimulation selectively increased the availability of acetylcholine, a neurotransmitter that’s vital for learning and memory. Its effect was as strong as the highest doses of drugs used to boost this brain chemical.
They also believe the memory benefits came from an increase in blood flow to the brain. This usually declines in Alzheimer’s disease.
With this new evidence the Georgia group is hoping to carry out a clinical trial in humans with early Alzheimer’s.
Their future hope is to produce closed-loop systems where implanted electrodes zap the brain only when needed.
