Cognitively Impaired

Cognitively or Decisionally Impaired Individuals


  • Unlike research involving children, prisoners, pregnant women, and fetuses, no additional Department of Health and Human Services (DHHS) regulations specifically govern research involving persons who are cognitively impaired.
  • While limited decision-making capacity should not prevent participation in research, it is important to keep in mind that additional scrutiny is warranted for research involving this population.

Assessing Capacity to Consent

  • There are no generally accepted criteria for determining competence to consent to research for persons whose mental status is uncertain or fluctuating so the role of the IRB in assessing the criteria proposed by the investigator is of major importance.
  • Refer to the document on the next page entitled “Evaluation to Sign Consent” for one option that may be used by investigator’s to assess an individual’s capacity to provide consent.
  • Both IRBs and clinical investigators must keep in mind that decision making capacity may fluctuate,
  • requiring ongoing assessment during the course of the research. The consent process should be ongoing.
  • The IRB, at its discretion, may require an outside witness to observe the consent process. 


  • The determination of a subject’s ability to understand the implications of the decision to participate in research is best made by the investigator.
  • There is no universally accepted test or standard for making a determination of comprehension.
  • This process should operate in research studies in much the same manner as the informed consent process in clinical treatment that does not involve research.

Voluntary Agreement

  • Research should not be conducted against the wishes of the subject, and making certain that the written documents are indeed a reflection of reality is the function of the individual researcher and the IRB.

Second Signature on the Informed Consent Document

  • The permission of another party is only required when the subject is determined to lack the legal ability to provide an informed consent.
  • For information about who may provide consent for on behalf of an incompetent adult, refer to the Section in this Manual entitled “Legally Authorized Representative.”

HawkIRB Application Questions

  • Section VI. Question 5 Does this project involve cognitively impaired subjects?
  • Section VI. Question 5-1. Describe how capacity to consent will be assessed.
  • Section VI. Question 5-2. Describe whether or not a subject’s capacity to consent might fluctuate over the course of the study, and if it does, how will you assess the subject’s willingness to continue throughout the study?