Vulnerable Subjects - Cognitively Impaired
All adults (including those with cognitive impairments) are presumed competent to consent unless legally judged to be incompetent.
Cognitively impaired persons are considered a vulnerable research population because their mental disability may compromise their capacity to make a reasoned decision about participation in a study.
People with Alzheimer's disease, dementia, mental illness and developmental disabilities may be considered cognitively impaired and may not be able to provide informed consent for participation in research.
In certain circumstances, when it is determined that a potential research participant is cognitively impaired, federal regulations and state statute permit researchers to obtain consent from a legally-authorized representative via surrogate consent.
For research protocols involving subjects who have fluctuating or limited decision-making capacity or prospective incapacity, Principal Investigators should establish and maintain ongoing communication with involved caregivers, consistent with the subjects' autonomy and with medical confidentiality.
The National Bioethics Advisory Commission issued a report on Research Involving Persons with Mental Disorders That May Affect Decision-making Capacity (December 1998). The recommendations set forth in that report should be carefully reviewed by Principal Investigators considering research involving such a population. Some of the requirements or considerations discussed in the report include:
Determining Decision-Making Capacity
A primary consideration when recruiting subjects with severe cognitive or psychiatric disorders is to establish procedures for determining which individuals are able to provide legally valid consent, and which are not.
The protocol reviewed by the IRB must detail a specific plan for the assessment of the decision-making capacity of the subject. The assessment will be conducted by the investigator for any subject who may qualify for Surrogate Consent. While there are no standardized measures for determining capacity to consent, subjects may be assessed on their ability to understand and to express a reasoned choice concerning the:
- Nature of the research and the information relevant to his/her participation;
- Consequences of participation for the subject's own situation, especially concerning the subject's health condition; and
- Consequences of the alternatives to participation.
The capacity to understand all of these concepts may not be necessary in order to consent to participate in a particular research protocol -- greater capacity is required for higher-risk protocols. This assessment should be used for determining the capacity of the surrogate as well, if necessary.
In protocols in which surrogate consent has been approved by the IRB, assessment of the decision-making capacity of the surrogate should be implemented only when the investigator has reason to believe that the subject's decision-making capacity may be impaired.
Consent for Cognitively Impaired
To have the option to obtain consent from a subject's legally-authorized representative, the investigator must request the use of surrogate consent.
When consent will be obtained from a legally-authorized representative (surrogate), the IRB usually will require that the assent of the subject be obtained.
Assent is defined as affirmative agreement to participate in research. Failure to object does not qualify as assent.
For more information on the use of a legally-authorized representative, see Surrogate Consenrt.