Can Researchers Continue Collecting Data From Someone Who Has Lost the Capacity to Consent?

What Happens When Someone Who Consented Can No Longer Make the Research Decision?

A participant had full decision-making capacity when they joined a longitudinal study. Months later, an illness, injury, cognitive decline, acute medical event, or another change leaves them unable to provide informed consent for continuing research participation.

The research team already has a valid consent form. Can they simply continue collecting data because the participant previously agreed?

Not necessarily. Earlier consent is highly relevant, but loss of consent capacity can change who may authorize continuing research and what protections are required. The answer depends on the nature of the research, what the participant previously authorized, the approved protocol, applicable law, and whether another valid consent pathway exists.

Prior Consent Does Not Automatically Settle Future Participation

Loss of Consent Capacity Changes the Authorization Question

Consent Capacity Is Specific to the Decision

Decision-making capacity should not be treated as a permanent label attached to a person. SACHRP describes consent capacity as existing along a continuum and emphasizes that it is task-specific. A person may be able to make some decisions while lacking sufficient capacity for a more complicated research decision. Capacity can also improve, deteriorate, or fluctuate over time.

This matters because researchers should not infer incapacity merely from a diagnosis, age, disability, communication difficulty, or an unusual decision. The relevant question is whether the participant can make the particular research decision required at that time.

A Consent Signed While the Participant Had Capacity Still Matters

Losing capacity does not erase the fact that the participant previously made an autonomous decision to join the study. That earlier choice may provide important evidence about the person's wishes and can be relevant to subsequent decision-making.

But it does not follow that the original consent authorizes every research activity indefinitely. Under HHS guidance, when an adult lacks capacity to consent, consent for research participation generally must come from a legally authorized representative unless an applicable IRB-approved waiver or other permitted exception applies. Who qualifies as a legally authorized representative depends on applicable law.

The Study Should Anticipate Loss of Capacity When It Is Foreseeable

Some studies involve populations in which declining or intermittent capacity is reasonably foreseeable. Longitudinal research involving progressive cognitive disorders is an obvious example, but capacity can also change because of acute illness, injury, treatment effects, or other circumstances.

OHRP recommends that investigators and IRBs conducting longitudinal research in which decisional impairment may develop consider, at the outset, whether prospective participants should designate someone who could serve as a legally authorized representative if permitted by applicable law.

SACHRP similarly recommends planning for reassessment, redisclosure of information, reconsent, and surrogate-based consent procedures when changes in capacity are anticipated. The protocol should not wait until a participant loses capacity to ask, for the first time, what should happen next.

Who Can Authorize Continued Research?

The answer is jurisdiction-specific. Under the U.S. Common Rule, a legally authorized representative is an individual, judicial body, or other body authorized under applicable law to consent on behalf of a prospective participant to participation in the research procedures involved.

This means that being a spouse, adult child, caregiver, emergency contact, or health-care proxy does not automatically make someone authorized to consent to research in every jurisdiction and circumstance. The relevant law and institutional determination must be checked.

Continued Data Collection Is Not One Uniform Activity

Researchers should identify what “continuing data collection” actually means. Reviewing existing records, conducting a questionnaire, obtaining a blood sample, administering an investigational intervention, and performing an invasive procedure are not ethically interchangeable.

The risks, burdens, scientific necessity, and applicable consent requirements can differ considerably. A protocol may permit some follow-up after loss of capacity while imposing different conditions on interventions or procedures. Researchers should therefore avoid asking only whether “the study” can continue and instead examine the specific research activities proposed.

The Participant Should Still Be Involved as Much as Possible

Loss of capacity does not make the participant ethically invisible. SACHRP recommends involving people with impaired consent capacity in research decisions to the extent possible and consistent with their abilities and wishes. A legally authorized representative's permission should not become an excuse to stop communicating with the participant.

A person who cannot provide legally effective informed consent may still understand a simplified explanation, express preferences, cooperate willingly, or object to a procedure. Those expressions can remain ethically important.

Dissent Deserves Particular Attention

SACHRP recommends that studies involving participants who lack consent capacity consider what constitutes assent and dissent, including nonverbal actions indicating unwillingness to participate in a procedure. This is especially important when participants have limited ability to communicate verbally.

A representative's authorization should therefore not be treated as permission to override resistance automatically. The protocol, applicable law, clinical context, and ethics approval determine how dissent is handled, but researchers should recognize it rather than treating physical or verbal resistance as a mere inconvenience.

This connects directly with the broader problem of a participant who no longer appears comfortable participating. Present expressions of unwillingness matter even when formal consent authority has shifted to another person.

What If Capacity Returns?

Temporary loss of capacity creates an important reversal point. OHRP states that when a participant who was represented by a legally authorized representative regains the capacity to consent, the participant's own consent must be obtained for further research because the representative's consent no longer substitutes for the participant's decision.

ICH Good Clinical Practice similarly provides that participants or their legally acceptable representatives should be informed as soon as possible in emergency circumstances and consent should be requested as appropriate.

Researchers should therefore not assume that surrogate authorization, once obtained, remains the controlling authorization indefinitely.

Loss of Capacity Is Different From Forgetting

A participant who has forgotten a procedure but understands it after explanation may still be fully capable of consenting. Capacity concerns become more substantial when the participant cannot adequately understand or use information relevant to the research decision despite appropriate support.

Researchers should therefore distinguish genuine loss of decision-making ability from ordinary forgetting of previously explained study information. Conflating the two risks unnecessarily removing autonomy from participants who remain capable of making their own decisions.

When Capacity Declines During a Longitudinal Study

The critical point is that the participant's earlier consent neither disappears nor automatically authorizes everything that follows. The change in capacity activates the safeguards and decision-making process established for that situation.

Common Mistakes After a Participant Loses Consent Capacity

Do Not Improvise After Capacity Is Lost

The best time to decide what happens after loss of capacity is before it occurs, particularly when the study population makes such a change foreseeable.

When a Participant May Have Lost Consent Capacity

Questions About Research After Loss of Consent Capacity

Loss of Capacity Requires a Valid Basis for Continued Research

How to Cite This Guide

This guide is intended to be read, shared, and used in research, teaching, and academic work. If you draw on its ideas, explanations, or other content, please acknowledge the source by citing the guide. Doing so gives appropriate credit and helps your readers locate the original resource.