Electrical brain stimulation for cognitive enhancement – maybe too soon for the DIY kit

If someone suggested you could boost your brainpower with a small burst of electrical stimulation from electrodes attached to your head, would you give it a try? Apparently, some people have been doing exactly that, either buying ready-made kits designed for the purpose or using instructions online to build their own DIY versions.

New research has shown that while such transcranial electrical stimulation may indeed provide a benefit to some, it appears to depend on specific characteristics of the individual. The question raised by the study is then: “cognitive enhancement or cognitive cost”?

What did the research say?

In a recent study from Dr Roi Cohen Kadosh’s research group at the University of Oxford, the effect of transcranial electrical stimulation (tES) on cognitive performance was examined. tES is basically when electrodes which can deliver low current electrical stimulation are applied directly to the head, and the study used a specific type called transcranial direct current stimulation (for a nice description, the Guardian’s piece on the study has a really good graphic). The researchers were interested in the effect of tES in the context of a mathematical task in individuals who were either high or low on mathematics anxiety. In those with high mathematics anxiety, the theory suggests that they perceive mathematical tasks negatively, that expectation affects their emotional response and diverts “cognitive resources” from the task. That is, worrying about the task limits how much you can throw at it. tES has been shown to be able to reduce negative emotional responses when applied to specific parts of the skull, so the current study was designed to see how those with high mathematics anxiety might benefit.

The study, published in the Journal of Neuroscience, is open access which means the original paper is freely available for you to read, and it gives a really good overview of the methods employed. Very simply, a mathematics anxiety scale was used to find the most and least anxious individuals from an original sample of 165 (giving 25 and 20 in the 2 groups respectively). When then asked to perform the mathematics task, those in the high anxiety group were slower (they were timed to see how quickly they responded). While electrical stimulation had an effect on performance, interestingly, the effect differed across the high and low anxiety groups: stimulation benefited performance in the high anxiety group, but was detrimental to performance in the low anxiety group. The effect was reported as independent of actual mathematical ability and gender.

The study also explored the levels of cortisol (a stress hormone) before and after the task, and suggested that cortisol levels followed a similar pattern: in those with high mathematics anxiety, electrical stimulation (and better mathematics performance) resulted in lower levels of cortisol. The researchers were careful to point out that while this supports one possible physiological pathway underlying the effect, it needs more detailed exploration. During the study, the participants also completed another, non-mathematics task, and for both high and low anxiety groups, electrical stimulation impaired performance. The researchers therefore discussed that while some benefits were apparent (in one group), other cognitive processes were impaired by the same stimulation.

Importantly, the study began by highlighting how tES “produces benefits across the psychological spectrum”, but that importantly, much of this work has not addressed how different individuals might benefit or not, or in what situations. These are clearly important issues to address, and will hopefully receive more attention given the potentially interesting benefits from the technique.

What did the media say?

Frankly, very little. In terms of mainstream media, there was an excellent piece in the Guardian but the only other coverage I found of the study was in New Scientist, a more specialist outlet. It’s a shame that the media have almost completely missed the release of this small but interesting study. That might be because it urges caution and consideration of this new technology, rather than a quick fix. But you can be sure that this topic will figure in future posts on Research the Headlines, if this coverage of companies getting products ready for market is anything to go by.

The bottom line.

With many things in life, if there’s an easy way to do something you can be guaranteed most of us would opt for it. And, in most cases, why not? In the current context, direct electrical stimulation does appear to have some potentially interesting applications. When it comes to important health outcomes, however, these early results with caveats are then often lost in the context of the marketing of a product specifically designed to treat problem X. In terms of boosting brain power, we’ve seen this with brain training for example, even when expert opinion has generally been stacked against the claims of the industry. Might direct electrical stimulation be the next fad to boost your brain? Possibly, but let’s hope that if it does, that the research highlighting who might benefit and in what circumstances precedes the marketing department’s latest pitch. As they often say on TV, don’t try this at home (yet).

Sarkar, A., Dowker, A. & Cohen Kadosh, R. (2014). Cognitive Enhancement or Cognitive Cost: Trait-Specific Outcomes of Brain Stimulation in the Case of Mathematics Anxiety. The Journal of Neuroscience. DOI:10.1523/JNEUROSCI.3129-14.2014