Nav: Home

No evidence that brain-stimulation technique boosts cognitive training

May 25, 2017

Transcranial direct-current stimulation (tDCS)--a non-invasive technique for applying electric current to areas of the brain--may be growing in popularity, but new research suggests that it probably does not add any meaningful benefit to cognitive training. The study is published in Psychological Science, a journal of the Association for Psychological Science.

"Our findings suggest that applying tDCS while older participants engaged in daily working memory training over four weeks did not result in improved cognitive ability," explains researcher Martin Lövdén of Karolinska Institutet and Stockholm University.

"The study is important because it addresses what has arguably been the most promising cognitive application of tDCS: the possibility of long-term cognitive enhancement from relatively limited practice on select cognitive tasks," Lövdén adds. "Cognitive enhancement is of interest not just to scientists, but also to the student studying for final exams, the gamer playing online games, and the retiree remembering which pills to take. Because of this large audience, it is of utmost importance to conduct systematic research to disentangle hype from fact."

Working memory--our capacity for holding information in mind at any given moment--underlies many fundamental cognitive processes and is linked with some aspects of intelligence. Research has shown that working memory training improves working memory performance but it's unclear whether this specific training can yield improvements to broader cognitive abilities.

Recent interest and publicity surrounding the potential effects of tDCS--which involves conducting a weak electrical current to the brain via electrodes on the scalp--led Lövdén and colleagues to wonder: Could using tDCS during cognitive training enhance brain plasticity and enable transfer from working memory to other cognitive processes?

The researchers enrolled 123 healthy adults who were between 65 and 75 years old in a 4-week training program. All participants completed a battery of cognitive tests, which included tasks that were incorporated in the training and tasks that were not, at the beginning of the study and again at the end. Those randomly assigned to the experimental group trained on tasks that targeted their ability to update mental representations and their ability to switch between different tasks and rules, while those in the active control group trained on tasks that focused on perceptual speed.

As they completed the training tasks, some participants received 25 minutes of tDCS current to the left dorsolateral prefrontal cortex, an area of the brain that plays a central role in working memory; other participants were led to believe they were receiving 25 minutes of current, when in actuality the current was only active for a total 30 seconds.

Comparing participants' performance before and after training indicated that those who received working memory training did improve on the updating and switching tasks they had encountered during training and on similar tasks that they had not encountered previously.

But there was no evidence that tDCS produced any additional benefit to the working memory training--at the end of the study, participants who received tDCS did not show greater improvement than their peers.

When the researchers pooled the data from this study with findings from six other studies, they again found no evidence of any additional benefit from working memory training that was combined with tDCS.

Given strong public interest in cognitive enhancement, Lövdén and colleagues urge caution when it comes to this as-of-yet unproven application of tDCS:

"A growing number of people in the general public, presumably inspired by such uninhibited optimism, are now using tDCS to perform better at work or in online gaming, and online communities offer advice on the purchase, fabrication, and use of tDCS devices," the researchers write. "Unsurprisingly, commercial exploitation is rapidly being developed to meet this new public demand for cognitive enhancement via tDCS, often without a single human trial to support the sellers' or manufacturers' claims."

"These findings highlight exactly how limited our knowledge is of the mechanisms underlying the potential effects of tDCS on human cognition and encourages the research community to take a step back and focus its resources on developing strategies for uncovering such mechanisms before using the technique in more applied settings," Lövdén concludes.
-end-
Co-authors on the study include Jonna Nilsson, Alexander V. Lebedev, and Anders Rydström of Karolinska Institutet and Stockholm University.

This research received funding from the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP7/2007-2013) and ERC Grant No. 617280 -REBOOT. Martin Lövdén was also supported by a Distinguished Young Researchers grant from the Swedish Research Council (446-2013-7189).

For more information about this study, please contact: Martin Lövdén at Martin.Lovden@ki.se.

The article abstract are available online: http://journals.sagepub.com/doi/abs/10.1177/0956797617698139

The APS journal Psychological Science is the highest ranked empirical journal in psychology. For a copy of the article "Direct-Current Stimulation Does Little to Improve the Outcome of Working Memory Training in Older Adults" and access to other Psychological Science research findings, please contact Anna Mikulak at 202-293-9300 or amikulak@psychologicalscience.org.

Association for Psychological Science

Related Brain Articles:

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.
Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.
Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.
Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.
BRAIN Initiative tool may transform how scientists study brain structure and function
Researchers have developed a high-tech support system that can keep a large mammalian brain from rapidly decomposing in the hours after death, enabling study of certain molecular and cellular functions.
Wiring diagram of the brain provides a clearer picture of brain scan data
In a study published today in the journal BRAIN, neuroscientists led by Michael D.
Blue Brain Project releases first-ever digital 3D brain cell atlas
The Blue Brain Cell Atlas is like ''going from hand-drawn maps to Google Earth'' -- providing previously unavailable information on major cell types, numbers and positions in all 737 brain regions.
Landmark study reveals no benefit to costly and risky brain cooling after brain injury
A landmark study, led by Monash University researchers, has definitively found that the practice of cooling the body and brain in patients who have recently received a severe traumatic brain injury, has no impact on the patient's long-term outcome.
Brain cells called astrocytes have unexpected role in brain 'plasticity'
Researchers from the Salk Institute have shown that astrocytes -- long-overlooked supportive cells in the brain -- help to enable the brain's plasticity, a new role for astrocytes that was not previously known.
Largest brain study of 62,454 scans identifies drivers of brain aging
In the largest known brain imaging study, scientists from Amen Clinics (Costa Mesa, CA), Google, John's Hopkins University, University of California, Los Angeles and the University of California, San Francisco evaluated 62,454 brain SPECT (single photon emission computed tomography) scans of more than 30,000 individuals from 9 months old to 105 years of age to investigate factors that accelerate brain aging.
More Brain News and Brain Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.