Building Novel Data-Driven Standards for Commercial tDCS: Meta-Analysis, Policy, and Ethics

Abstract

Neurotechnology is expanding rapidly, and it seems to be a matter of time before many products are widely available. One of the first technologies on the consumer market is transcranial direct current stimulation (tDCS). Electrical stimulation has a long history. tDCS has recently garnered research, clinical, and consumer interest. It employs 1-2mA current, thought to induce electric fields that alter cortical excitability. While tDCS has had dubious results on a myriad of clinical and cognitively enhancing indications, it is advertised for improving mood, motor skills, working memory, and more. A tDCS community has been inspired by that research, emboldened by the simple and inexpensive design of tDCS. These individuals build do-it-yourself (DIY) products and buy direct-to-consumer (DTC) devices, which the Food and Drug Administration (FDA) recently classified as lifestyle products rather than medical devices. Sociological research shows that these individuals want authorities to guide them through the research. The FDA and many researchers have noted the need for thoughtful policy proposals. This thesis proposes using meta-analysis to evaluate tDCS devices and inform consumers. It explores three clinical analogues of oft-advertised indications: craving, chronic stroke motor improvement, and depression. All three displayed small-to-moderate effects compared to sham (Hedges’ g craving = 0.340; g depression = 0.531; g stroke = 0.486). A case study on Focus, one of the largest tDCS companies, revealed that in working memory tasks, Focus’ device compares unfavorably to the tDCS standard and other interventions. Based on this proof of concept, this thesis explores the subsequent policy and ethical considerations—making recommendations for how to use a data-driven approach to constructively engage with the tDCS industry and community. This model could be constructively used to inform consumers about technologies that are either scientifically or ethically dubious.