"Unfocus" on foc.us: commercial tDCS headset impairs working memory.

Laura Steenbergen,Bernhard Hommel,Roberta Sellaro,Simone Kühn,Ulman Lindenberger,Lorenza S Colzato

doi:10.1007/s00221-015-4391-9

Laura Steenbergen, Bernhard Hommel + Show 4 more

Open Access

https://doi.org/10.1007/s00221-015-4391-9

Copy DOI

Abstract

In this study, we tested whether the commercial transcranial direct current stimulation (tDCS) headset foc.us improves cognitive performance, as advertised in the media. A single-blind, sham-controlled, within-subject design was used to assess the effect of online and off-line foc.us tDCS—applied over the prefrontal cortex in healthy young volunteers (n = 24) on working memory (WM) updating and monitoring. WM updating and monitoring, as assessed by means of the N-back task, is a cognitive-control process that has been shown to benefit from interventions with CE-certified tDCS devices. For both online and off-line stimulation protocols, results showed that active stimulation with foc.us, compared to sham stimulation, significantly decreased accuracy performance in a well-established task tapping WM updating and monitoring. These results provide evidence for the important role of the scientific community in validating and testing far-reaching claims made by the brain training industry.

Highlights

A recent initiative supported by several eminent research institutes and scientists calls for a more critical and active transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that involves passing a constant direct electrical current through the cerebral cortex flowing from the positively charged anode to the negatively charged cathode (Paulus 2011; Nitsche and Paulus 2011)
Previous studies using tDCS CE-certified devices have shown that excitability-enhancing anodal tDCS applied over the left dorsolateral prefrontal cortex promotes working memory (WM) updating in healthy individuals and patients, both when combined with excitability-diminishing cathodal tDCS over the right prefrontal cortex, either the right supraorbital region (e.g., Fregni et al 2005; Boggio et al 2006; Ohn et al 2008; Jo et al 2009; Keeser et al 2011; Teo et al 2011) or the right dorsolateral prefrontal cortex
WM performance can be enhanced by video game playing (Colzato et al 2013a), an activity for which the use of the tDCS headset foc.us is recommended to boost performance via prefrontal cortex stimulation

Summary

Introduction

A recent initiative supported by several eminent research institutes and scientists calls for a more critical and active tDCS is a noninvasive brain stimulation technique that involves passing a constant direct electrical current through the cerebral cortex (via electrodes placed upon the scalp) flowing from the positively charged anode to the negatively charged cathode (Paulus 2011; Nitsche and Paulus 2011). Spontaneous cortical excitability is either enhanced or reduced depending on the current polarity: Anodal stimulation leads to a resting-membrane depolarization in the cortical region under the electrode, increasing the probability of neural firing, whereas cathodal stimulation leads to a resting-membrane hyperpolarization, reducing the probability of neural firing (Nitsche and Paulus 2000; Nitsche et al 2003). This technique has developed into a promising tool to boost human cognition (Fregni et al 2005; Fox 2011; Kuo and Nitsche 2012, 2015). WM performance can be enhanced by video game playing (Colzato et al 2013a), an activity for which the use of the tDCS headset foc.us is recommended to boost performance via (left anodal–right cathodal) prefrontal cortex stimulation

Objectives

Results

Conclusion