Governing citizen use of brain stimulation technologies: what role for scientists?

Colton Smith’s 2017 essay provides an informative history of transcranial direct current stimulation (tDCS) and its use in research and clinical settings. More importantly, he also discusses a growing trend in brain stimulation technology: the availability and use of tDCS and other brain stimulation devices by individuals outside the scientific community. In his essay, Smith does a nice job of reminding us that just because a technology has been around for a while (in the case of tDCS, over two centuries now), there can still be important gaps in our understanding of how it works and its possible consequences. He voices several concerns about the lack of acknowledgement or attention to the potential short- and long-term effects of using brain stimulation technologies outside of research and clinical settings.

Smith’s essay expresses a clear protective stance towards ‘citizen scientists’ who are experimenting with tDCS technology, particularly those who might not fully understand the (still under-determined) risks involved. He asserts a role for the scientific community in engaging with citizen scientists to ‘counter the false assertions being put out by companies selling tDCS devices.’ It is easy to understand where this sentiment comes from; however, we believe it is instructive on several counts to take a step back and look at how tDCS is currently being used and described within the scientific community. In our view, this leads to somewhat different conclusions about some of the sources of current problems and their possible solutions. In particular, it may prove difficult to draw as clear a line as Smith wishes to between tDCS practices within the scientific and citizen science or do-it-yourself communities.

Using tDCS

First, we look at some of the everyday practices surrounding the use of tDCS technology in research contexts. One of us (PM) uses tDCS and related stimulation technologies for laboratory research purposes. It is worth noting how little formal training accompanies the use of this technology by scientists; perhaps because it has been around for so long. In practice, learning to use tDCS is a largely informal process, in which scientists read relevant scientific literature and documentation, discuss techniques and protocols with colleagues, and perhaps shadow operation of the machinery by another researcher. There are no specific certifications, safety trainings, or licenses required to operate this technology.

Over time, the scientific community has developed guidelines concerning safe and ethical conduct of brain stimulation research, including some guidance concerning maximum suggested stimulation frequencies (e.g. Wasserman 1998). Such guidance is non-binding but has been widely cited in research papers over the past 20 years. Use of a simple safety questionnaire is also advised, to screen research subjects for the possibility of adverse effects of brain stimulation; for example, the freely available questionnaire published by Keel, Smith, and Wasserman (2011) consists of 14 straightforward questions with Yes or No answers. This screening survey is not intended for use as a stop/go tool, but as a means of evaluating possible risks for individual subjects. How risks are then evaluated based on this type of questionnaire is an open question; it may be that some additional guidance on interpreting potential risks would be useful, both for the research community and for citizen scientists.

One key difference between research scientists and citizen scientists is that citizen scientists will typically experiment on their own brains, while scientists experiment on the brains of volunteer participants. How this affects willingness to take risks is a question worth investigating empirically. In general, though, it may prove difficult to impose different standards on citizen scientists who choose to experiment with brain stimulation technology. Ensuring that guidance already developed within the scientific community is made readily available to citizen scientists in accessible formats seems a clearly actionable point. But we should be careful not to apply significantly stricter standards for public use of tDCS than currently exists within the research community. Most research is currently performed on healthy subjects (in part because doing such studies on individuals with neurological conditions adds too much complexity to an already-tricky research puzzle). If we are calling for citizen scientists to avoid using these devices owing to potential consequences on the brain, how do we justify their use on healthy subjects by scientists in the laboratory?

Describing the effects of tDCS

Smith voices strong concern with the marketing schemes used by companies to sell stimulation devices, such as tDCS, to intrigue the public to purchase or create such technology. He writes that devices are described as providing the ‘ability to enhance alertness, boost focus, and even increase the capacity to learn.’ While it is certainly possible to argue that these claims may be exaggerated or misleading, it must be noted that many of them originate from within the scientific community itself.

There is a visible mismatch within the scientific literature between the types of tasks performed using tDCS, and the larger outcomes and claims that are then made about the technology’s capabilities. In many cases, scientists use brain stimulation technology to study its effects on the performance of very simple motor or cognitive tasks. These tasks are typically tightly controlled, and do not directly mimic everyday motor or cognitive tasks (Classen et al. 1998; Rosenkranz, Kacar, and Rothwell 2007; Reis et al. 2009; Galea and Celnik 2009; Waters-Metenier et al. 2014). Yet even in the research papers themselves, the implications of the research often extend far beyond what the authors have actually demonstrated. It may be that companies are following examples set by the research community, rather than inventing new claims about the potential of brain stimulation technologies.

To provide some specific examples, a seminal learning study reported by Muellbacher and colleagues showed that stimulation could improve the acceleration of a ballistic squeezing motion with the thumb and index finger (Muellbacher et al. 2002). Similarly, in the Cohen Kadosh et al. paper referenced by Smith, subjects showed an ability to improve at a task in which they were asked to identify the larger of two symbols displayed on a computer screen (Cohen Kadosh et al. 2010). While showing improvements in seemingly arbitrary abilities due to brain stimulation, the introductory and discussion sections of such papers typically extrapolate to propose significant potential for use in improving math skills and cognitive abilities more broadly. These are the claims that often circulate more widely. For example, press releases and news stories accompanying publication of the Cohen Kadosh et al. paper pick up on such excitement, using titles like ‘Electrical brain stimulation improves math skills, researchers show’ (Cell Press 2010) and ‘Zap, you’re smart! Mild brain shock stimulates math skills’ (Choi 2010), and mobilizing interviews and quotations from the study researchers about the real-world potential of this technology. While the researchers typically exercise caution about promising immediate benefits to users (‘more research’ is almost invariably needed), the framing of both scientific and news publications often encourage us to think these technologies are closer-to-market than they may actually be.

To be clear, we are not arguing that results from studies like those mentioned above do not demonstrate changes in learning or cognitive ability, but we do suggest these results are sometimes written in ways that jump quickly to real-world potential before having conducted the additional work required to show this. Understandably, the bigger-picture potential impacts can be easier to digest, and more readily attract public attention and research funding. However, it then becomes harder to protest against the use of very similar language when it finds its way to the advertising pages of a market-ready stimulation device. tDCS is not the only field currently suffering from the effects of enthusiastic promotion of research findings; the stem cell research community, for example, is increasingly concerned about the consequences of ‘overselling’ their science (Caulfield et al. 2016). They have recently published guidelines for their researchers about publishing and communicating their research.

What can be done?

Notwithstanding the caveats above, we think Smith’s call for concern over the marketing of brain stimulation technologies is warranted, in part owing to several of the existing safety and efficacy unknowns he outlines. Our calls to action may differ in kind, but not broadly in motivation.

First, we suggest that the moral and ethical responsibilities of scientists extend not just to honest and realistic communication with the public about possible risks and benefits of technologies like tDCS, but also to a duty within the scientific community to resist the pressures to overstate conclusions and ‘spin’ their work. Research papers should strive to focus on discussing scientific results in ways that limit the possibility of extrapolation for other purposes (e.g. by companies marketing brain stimulation devices).

Furthermore, all technologies are developed within broader systems of innovation that involve scientists, funders and investors, technology developers, publics, and regulators. tDCS and other brain stimulation technologies are no exception. Responsible innovation does not fall solely on the shoulders of scientists, nor of any single group in this landscape. To this end, regulators including the Food and Drug Administration (FDA) have a role to play in ensuring the safety of brain stimulation products on the market. The types of claims Smith identifies as being made by companies marketing brain stimulation devices could certainly bring those devices under the broad regulatory purview of the FDA (Zettler 2015; Wexler 2015). While changing the ‘non-invasive’ designation of tDCS seems unrealistic (based on the current definitions used for ‘invasive’ and ‘non-invasive’ devices), the choice of classification scheme applied by the FDA (e.g. to regulate tDCS technologies as Class I, II, or III devices) may have great influence over what kind of safety and efficacy data they require from companies for device approval. With this in mind, there may also be a role for scientists, publics, and technology developers to engage in conversations with the FDA about what constitute suitable safety and efficacy studies for tDCS, and to determine appropriate designations for tDCS devices – recognizing that these may have consequences for both laboratory research and the commercial marketplace.

It can certainly be harder to regulate technologies once they have entered the market, particularly if they are in widespread use. Here the Federal Trade Commission (FTC) also has a role in policing accurate and scientifically supported marketing claims made by companies selling brain stimulation devices. This said, it is not clear that FDA and FTC regulatory mechanisms would capture all tDCS devices currently used in home settings, given that some citizen scientists are not purchasing tDCS equipment but rather are making and using their own brain stimulation devices (Wexler 2015).

Whether individuals should have the right to make and use tDCS technologies in their own homes raises broader questions about access to neuroenhancement (or neuron-altering) technologies. Should a technology long deemed ‘safe’ in the laboratory not be allowed to move into other settings? Smith outlines a set of new risks and questions that emerge when putting brain stimulation technologies in the hands of citizen consumers – for example, around long-term effects of device use, and the potential for addiction. These are certainly questions worthy of empirical research. Fostering open conversations about parallels and differences between brain stimulation technologies and other commonplace neuromodulators like coffee, alcohol, and tobacco may help to deepen our understanding of where and how a technology like brain stimulation fits in with society’s norms and values – and what kinds of motivations and risks are identified as most salient by citizen scientists. Ultimately, we believe that effective practices for the use and governance of brain stimulation devices will require open and constructive dialogue among all core stakeholders; while scientists bring important voices and knowledge to this debate, these decisions are not for the scientific community alone to make.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Patrick McGurrin has a bachelor’s degree in psychology from the University of Pittsburgh and is currently pursuing his Ph.D. in neuroscience, as well as a Certificate in responsible innovation, at Arizona State University. His research uses non-invasive technologies to study motor, sensory, and cognitive aspects of dexterous manipulation in humans.

Emma Frow is an assistant professor at Arizona State University, with a joint appointment in the School for the Future of Innovation in Society and the School of Biological & Health Systems Engineering. Her research focuses on standard-setting and governance of emerging biotechnologies.

ORCID

Patrick McGurrin http://orcid.org/0000-0002-6962-9582