This chapter explores ethical issues in obtaining ongoing consent for clinical research involving cognitively vulnerable patient populations. Stakeholders in these challenges include researchers, sponsors, study participants, caregivers and other legally authorized representatives, and research oversight boards. First, this chapter examines existing conceptual frameworks and proposed safeguards for the protection of cognitively vulnerable research participants, including double consent, proxy consent with participant assent, advance consent, and process consent. This chapter then proposes an inclusionary approach to obtaining ongoing consent to research participation when cognition could fluctuate over the course of research participation. Proposed safeguards and modifications to the consent process should address duration of research participation, the nature and timing of research-related risks, expected and unexpected fluctuations in decision-making capacity, and the process of exiting a clinical trial. The proposed framework is then applied to the specific context of implanted neural device trials, with special attention to considerations for device explant.