Recently we found that people show impaired working memory after receiving low intensity electrical stimulation from a commercial, freely available device, administered to the frontal part of the brain. We carried out this study at the Leiden Institute of Brain and Cognition in collaboration with our fellow colleagues from the Max Planck Institute on Human Development.

Commercial non-invasive brain stimulation device to the test
Following the prominent suggestion by several eminent research institutes and scientists, we were the first to investigate whether and to what degree the application of a commercial non-invasive brain stimulation device, called transcranial direct current stimulation (tDCS), improves cognitive performance, as advertised in the media. Given the potential risks of misusing tDCS, and that its long-term effects on the brain have not been fully explored, we believed that there was the need for regulations or official guidelines for the personal use of tDCS.

The research method
24 healthy participants received a low intensity current administered by electrodes to the frontal part of the brain through the scalp by means of a commercial tDCS device (foc.us headset - v.1). People came twice to the lab and received a sham (fake stimulation) or a mild electrical current which activates neurons in the targeted region. During, and after the stimulation, we asked participants to perform a working memory task in which they had to update remembered information.

Working memory impaired
Compared to when the participants received the fake stimulation, the active stimulation impaired memory performance. Even if preliminary, we believe that these results show the fundamental critical and active role of the scientific community in evaluating the sometimes far-reaching, sweeping claims from the brain training industry with regard to the impact of their products on cognitive performance.

Steenbergen, L., Sellaro, R., Hommel, B., Kühn, S., & Colzato, L.S. (2015). “Unfocus” on foc.us: Commercial tDCS headset impairs working memory. Experimental Brain Research. DOI 10.1007/s00221-015-4391-9