The emergence of new technologies might challenge our assumptions about biomedical research: medical progress may not only cure but enhance human capacities. In particular, the emergence of brain-machine interfaces will admittedly allow disabled people to move or communicate again, but also has various military applications, such as remote control of drones and avatars. Although there is no express legal framework pertaining to the experimental phase of human enhancement techniques, they are actually constrained by international law. According to international humanitarian law, civilians and prisoners of war may be subjected to experiments only when required by their state of health or for medical treatment. According to international human rights law, experimentations are permissible when they meet two conditions: (i) free consent, and (ii) proportionality (that is, the adequacy of risk and benefit). In light of these conditions, this article assesses the situations in which experimentation involving brain-computer interfaces would be lawful. It also gives specific attention to those experimentations carried out on members of the armed forces. In fact, owing to the military hierarchy and the unique nature of its mission (to protect national security at the risk of their own lives), it is necessary to determine how the military may comply with this legal framework.

Closed-loop medical devices such as brain-computer interfaces are an emerging and rapidly advancing neurotechnology. The target patients for brain-computer interfaces (BCIs) are often severely paralyzed, and thus particularly vulnerable in terms of personal autonomy, decisionmaking capacity, and agency. Here we analyze the effects of closed-loop medical devices on the autonomy and accountability of both persons (as patients or research participants) and neurotechnological closed-loop medical systems. We show that although BCIs can strengthen patient autonomy by preserving or restoring communicative abilities and/or motor control, closed-loop devices may also create challenges for moral and legal accountability. We advocate the development of a comprehensive ethical and legal framework to address the challenges of emerging closed-loop neurotechnologies like BCIs and stress the centrality of informed consent and refusal as a means to foster accountability. We propose the creation of an international neuroethics task force with members from medical neuroscience, neuroengineering, computer science, medical law, and medical ethics, as well as representatives of patient advocacy groups and the public.