Advance Research Directives and Supported Consent in Dementia Research.

Obtaining ethically valid consent for clinical research involving persons with dementia remains a persistent challenge, as cognitive decline disrupts traditional models of informed consent based on participant's capacity to understand the content and freely decide. As a result, individuals are frequently excluded from research or enrolled through proxy consent that may insufficiently reflect their values and autonomous commitments. Recent ethical and policy debates have increasingly promoted advance research directives and supported decision‑making as means of addressing these challenges and enhancing inclusion. This manuscript examines the ethical roles and limitations of advance research directives and supported consent in dementia research. Based on the concept of precedent autonomy, we maintain that advance research directives have distinctive normative importance in the research setting, where participation may involve risks or burdens without direct therapeutic benefit. At the same time, we critically consider supported decision‑making, identifying ethical risks including undue influence, oversimplification of material information, misinterpretation of assent, and the substitution of supporters' preferences for participants' choice. To address these tensions, we propose a hybrid consent model that integrates advance research directives with supported decision‑making, ongoing assessment of assent and dissent, and procedural safeguards. This model implies consent as a continuous ethical process rather than a single event, balancing respect for prior autonomous commitments with sensitivity to present expressions, and well-being. We suggest that such an approach offers a more ethically defensible and practical framework for dementia research, consistent with rights‑based principles and established research ethics standards.