Zap Away!

Speaking as a sometimes forgetful “senior citizen,” when I found out that non-invasively zapping brains with electricity can result in measurable improvements in memory, that’s something I’m going to remember.

Credit: Ward Sutton for Wired

I hope. 

In research published in Nature Neuroscience by Grover, et. al., a team lead by Boston University cognitive neuroscientist Robert Reinhart produced improvements in both long term and short term (working) memory through a series of weak electric stimulation – transcranial alternating current stimulation (tACS). The authors modestly claim: “Together, these findings suggest that memory function can be selectively and sustainably improved in older adults through modulation of functionally specific brain rhythms.”

The study provided the stimulation using something that looks like a swimming cap with electrodes, applied for twenty minutes a day for four days.  The population was 150 people, broken up into three separate experiments, all ages 65 to 88.

tACS device. Credit: Dr. Robert Reinhart

The results were amazing.  “We can watch the memory improvements accumulate … with each passing day,” Dr. Reinhart marveled. 

Previous studies had suggested that long term and working memories had distinct mechanisms, in different parts of the brain, and this study seems to have demonstrated that fairly conclusively.  “We could improve either short-term or long-term memory separately,” Dr. Reinhart said. “And with this intervention across four consecutive days, we could change memory and watch the benefits accumulate over those days, which is striking.” 

Even more important, the gains persisted even a month later, with the greatest gains accruing to the participants who had the lowest cognitive function levels prior to the study.

“That’s really one of the take home messages here—that it’s not just about stimulating a brain area, but it’s about stimulating a brain area at a specific frequency, so that it can then drive network communication,” Daniel Press, chief of the cognitive neurology unit at Beth Israel Deaconess Medical Center, told The Wall Street Journal.  (Dr. Press wasn’t involved in the research).

Other researchers not involved in the study were impressed.  “Their results look very promising,” says Ines Violante, a neuroscientist at the University of Surrey. “They really took advantage of the cumulative knowledge within the field.”

“I was both impressed and surprised by this by this paper,” Simon Hanslmayr, a cognitive neuroscientist at the University of Glasgow,” said to Nature, with the results linked to “consistent and quite strong improvements in memory.”

“This is a really elegantly designed study,” Katharina Klink, a brain scientist at the University of Bern told StatNews. “These are such small currents that are being used, so to see effects on memory function after one month of not having any stimulation done to the brain, that’s quite impressive.” 

“I believe this is the future of neurologic intervention, to help strengthen networks in our brains that may be failing," Dr. Gayatri Devi, a clinical professor of neurology and psychiatry at the Zucker School of Medicine at Hofstra/Northwell, told CNN. "Additionally, treatment may be tailored to each person, based on that individual's strengths and weaknesses, something pharmacotherapy is not able to do.”

“This was a very short intervention which produced both an immediate effect and a very durable one,” Marom Bikson, a neural engineer at the City College of New York, told MIT Technology Review. “More research is needed, but if this works out it could be in every doctor’s office … and it could eventually be something that people use at home.” 

Dr. Richard Isaacson, director of the Alzheimer's Prevention Clinic in the Center for Brain Health at Florida Atlantic University's Schmidt College of Medicine, agrees, telling CNN: “In an ideal world, a portable at-home device that could offer this therapy would be the eventual goal.”

I’d buy one of those…and one for my wife.

We can hope for something like this...someday

The study differed from previous efforts in a couple of significant ways.  One was applying the tACS over a period of days, rather than in a single session.  The second was targeting seniors rather than younger people, whose memory issues may be harder to identify or modify. 

Dr. Reinhart prefers to refer to tACS as brain modulation rather than brain stimulation, since the currents are too low to trigger brain cells to fire.  “They’re noninvasive, safe, extremely weak levels of alternating current,” he stresses.  Moreover, he adds: “When the current is running, you feel like a mild tingling or itching or poking or warming sensation.”  “Zap” may be too strong a word.

Study coauthor Shrey Grover told Nature that future areas of research include whether the tACS can impact other memory tasks, whether the improvements persist longer than a month, and whether it could help people with conditions like Alzheimer’s. “We’re hoping that we can extend upon this work in meaningful ways and contribute more information about how the brain works,” Dr. Grover says.

The study is more evidence that our brains are not as fixed as once thought.  “This plasticity is what allows the effects to be carried forward in time even when the stimulation has ended,” Dr. Grover told The Wall Street Journal.

By contrast with tACS, deep brain stimulation (DBS) has been around for several years, with good success in treating conditions like Parkinson’s, dystonia, and, most recently, it had significant effects in treating depression in a small study from UTHealth Houston.  But, you know, DBS involves implanting electrodes in the brain, so that swimmer’s cap-like device looks a lot more appealing.

DBS implants -- umm, no thanks. Photo by Zephyr/Science Photo Library

We’re a long way from clinical trials or FDA approved devices for tACS, so if someone tries to sell you a brain stimulation cap, it’d be wise to be skeptical.  “It will take more work to turn this into something that could actually help people with memory impairments,” said University of New Mexico neuroscientist Vincent Clark, who was not involved in the study.

But at some point in the future, yeah, we’re likely to have options like that.  As Dr. Reinhart told StatNews: “People are just overwhelmingly interested in augmenting their abilities to provide any kind of cutting-edge advantage.  I can imagine a future potentially where people are using stimulation.”

In the meantime, keep doing your Wordle, taking those walks, or swallowing your favorite (prescription or OTC) nootropic to help keep your memory fresh, but keep your hopes alive that a more effective, more targeted solution may be on the way.