Informed Consent under Impaired Capacity
Many implanted-BCI participants have conditions — advanced ALS, brainstem stroke with locked-in syndrome, high tetraplegia — that impair the very channels (speech, movement) through which consent is normally given and capacity assessed. This creates a tension: the people who could benefit most may be least able to communicate a fully informed, voluntary, and revocable choice, and their capacity may fluctuate over time.
Responsible practice uses accessible communication (including, paradoxically, the BCI itself), assessment of decision-making capacity for the specific decision, surrogate or supported decision-making where needed, and dynamic or staged consent rather than a single signature. It must guard against the therapeutic misconception (participants overestimating personal benefit from research), clarify that an investigational device is not a guaranteed therapy, and plan in advance for the withdrawal of consent and for the end of the study.
A participant with locked-in syndrome may be able to give and, crucially, withdraw consent only through the very communication BCI under study — a dependency that must be planned for so that a 'no' is always expressible.
The device may be the only channel through which consent can be affirmed or revoked.
Consent to implant is not consent to indefinite research burden; ongoing re-consent, an exit plan, and honesty about uncertain benefit are ethical minimums.