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What Is Assent, When Provided by an Adult Participant Lacking Capacity? And What Are WCG’s Expectations and the Investigator’s Responsibilities?


What is assent, when provided by an adult participant lacking capacity? What are WCG’s expectations and the investigator’s responsibilities, when the IRB Board provides assent instructions for adult participants who lack capacity to consent for themselves?


The term “assent” is often misinterpreted by stakeholders who are involved in the conduct of clinical research studies because it is commonly only associated with seeking affirmative permission from capable children as stated in U.S. federal regulations related to Protection of Human Subjects (21 CFR 50.3(n) and 45 CFR 46.402(b)).

However, an adult participant who lacks full capacity may still be able to be cognitively engaged in the consent discussion. They can also provide their assent to participate in the research study. Therefore, assent can be broadly interpreted as an affirmative agreement by either children or adults lacking capacity who have that capability.


The Board will provide assent instructions for the adult participants who lack capacity to consent for themselves and may require the investigator to obtain and document their assent, like with children. WCG’s IRB expects the investigator to involve both the participant and the appointed Legally Authorized Representative in the consent discussion. During the consent process, the investigator should holistically evaluate the participant’s engagement by assessing their cognitive presence, non-verbal facial and body gestures, any evidence of understanding, and subtle emotional reactions. Furthermore, to respect the participant’s autonomy, the investigator should also encourage the participant to communicate via common gestures, such as head-nodding, lifting arm to seek clarification or stop the discussion, and thumbs-up or down movements to engage with the investigator. However, the investigator is not limited to these techniques but may incorporate any reasonable methods including the help of others who have expertise in communicating with the participant.

After the consent discussion, the person obtaining assent will document the discussion as directed by the assent instructions. A participant’s rights and welfare are best protected when the investigator engages with the participant to the extent they are able, which is an on-going process throughout the study.