As articulated by the Nuremberg Code and the Belmont Report, and codified in federal regulations, research involving human subjects may be done only with the subjects' voluntary informed consent. However, any element of the informed consent process (relevant and sufficient information, decision-making capacity and subject voluntariness) may be compromised when conducting research involving elderly research subjects.
Meaningful and ethically valid informed consent requires that research subjects be given relevant and sufficient information including the purpose of the study, potential risks and alternatives to participation, and the subject's right to withdraw from the study at any time. Furthermore, investigators should inform potential research subjects that the primary objective of research is to acquire new knowledge and that personal clinical benefit may or may not occur (American College of Physicians, 2005).
Subjects must also understand the disclosed information. Investigators should ensure that subjects understand the information conveyed during the informed consent process since harm may occur as a result of the subject making a misinformed choice (i.e., a choice they would not have made if they had understood the information) (Ratzan, R., 1980). However, many research subjects, especially those who are ill or poorly educated, do not understand the purposes and risks of the studies in which they are participating even after consent has been obtained (Sachs, G. and Cassel, C., 1990). Informed consent forms can be long, complex and difficult to understand (LoVerde et al., 1989). Furthermore, research subjects participating in studies in a clinical setting may forget that they are, in fact, research subjects (Riecken, H. and Ravich, R., 1982).
Notably, systematic reviews of studies of the informed consent process have found that reduced understanding of conveyed information was associated with older age (Sugarman et al., 1998; Flory, J. and Emanuel, E., 2004). In addition, compared to younger persons, elders may have more difficulty in recalling information conveyed (Sachs, G. and Cassel, C., 1990). Impaired understanding and recalling of information by elders may be due to sensory deficits (e.g., vision and hearing), comorbid illnesses, diminished cognition, and other factors (Sugarman et al., 1998).
However, a number of strategies can improve the understanding of information. Simplified consent forms, multimedia approaches (e.g., video), quizzes, multiple disclosure sessions and especially generous one-on-one time with a study team member or educator are effective means of improving understanding (Sugarman et al., 1998; Flory, J. and Emanuel, E., 2004). Another promising tool for maximizing informed consent among potential research subjects who are frail and elderly is ''experienced consent.'' In a study of frail elders, a week-long trial of noninvasive testing to gain experience with a research study's methods resulted in significant increases in comprehension of the study methods and the number of subjects capable of weighing the risks associated with the study (Olde Rikkert, M., et al., 1997).
2. Voluntariness The first item of the Nuremberg Code is that ''the voluntary consent of the human subject is absolutely essential'' (Nuremberg Code, 1947) (Table 7.1). Subsequent codes, reports and regulations have reiterated this principle. Subjects, to the degree that they are capable, must be allowed to decide what shall and what shall not happen to them. Notably, despite the crucial role of voluntariness in the informed consent process, little empirical data regarding voluntariness has been published (Sugarman et al., 1998).
Autonomy may be limited for residents of long-term care institutions (e.g., nursing homes), most of whom are elders. When to eat and go to bed, choosing a roommate and other activities are largely controlled by the institution. Hence, it is not surprising that concerns exist about the possibility of obtaining voluntary consent for research from residents of long-term care institutions. Residents depend on the institution for food, shelter, medications and care. In the context of consent for research, this dependency may foster coercion; i.e., residents may not feel free to refuse to participate in research out of fears that their care will suffer if they refuse, especially if their clinicians are also the investigators (Bell, J., et al., 1987; Sachs, G. and Cassel, C., 1990; Sachs, G. and Cohen, H., 2003). Whereas independent research subjects can freely choose to continue or withdraw from a research study, institutionalized persons may perceive less freedom to choose because of needs for attention and care, and fear of rejection (Dubler, N., 1987).
3. Decision-making Capacity Decision-making capacity refers to a potential research subject's ability to understand, make and express a reasoned and meaningful choice about whether to participate in a research study. Of the elements of the informed consent process, decision-making capacity is often the most problematic for elders, since elders represent an age group most susceptible to illnesses that affect mental functioning (Marson, D., et al., 1994). Nevertheless, society and law assume that all adults are competent. In fact, the term competent is a legal term, and only a court can declare a person incompetent. Clinicians and investigators, however, may care for and work with elders who cannot effectively comprehend or manipulate information in a way that allows for weighing of the risks and benefits of, and alternatives to, a proposed intervention or research protocol. These patients lack decision-making capacity. Unlike competency, clinicians and investigators determine if a person has decision-making capacity.
Having a mental illness or an illness that affects cognition does not necessarily mean an individual lacks decision-making capacity (AGS Ethics Committee, 1998; Alzheimer's Association, 2004). Indeed, many elders with diminished cognition are not only legally competent, but also have decision-making capacity and can consent to participate in research. Capacity to consent need not be based on an overall state of competence. A patient can have diminished cognition (e.g., due to dementia) and still understand the purpose of the study (e.g., that it is research and may not provide a therapeutic benefit), the risks of participating in the study, and that he or she may refuse to participate. Instead, consent for participating in research studies of varying complexity requires varying levels of capacity. For example, a person may be able to effectively consent to participate in a minimal risk study (i.e., a study in which the risk and magnitude of harm to the subject are no greater than what the subject would encounter in daily life or during the performance of routine physical or psychological examinations or tests), but not a trial of a new drug or procedure (Dubler, N., 1987; Sachs, G. and Cohen, H., 2003).
Assessing the decision-making capacity of potential research subjects is an important step in the informed consent process. Capacity to consent for participating in research should include the following abilities: (a) ability to evidence a choice (i.e., ability to reach a decision and effectively communicate the decision); (b) ability to understand the nature of the research study and other information relevant to participants disclosed by the investigator; (c) ability to understand and appreciate the risks and consequences of participating or not participating in the study, and the procedures to follow if adverse events occur and if withdrawal from participation is desired; and (d) ability to manipulate information rationally (Alzheimer's Association, 2004; American Psychiatric Association, 1998).
Unfortunately, clinicians and investigators are uncommonly trained to assess the decision-making capacity of potential subjects and thereby have difficulty assessing capacity. In fact, those who are experienced in assessing decision-making capacity may disagree with each other. Furthermore, no universally accepted standardized tool for assessing decision-making capacity for research consent exists. Because of these facts, investigators assessing capacity have relied on subjective impressions and brief mental status tests (Marson, D., et al., 1994). One promising approach, however, is for investigators to incorporate details of a given study into open-ended questions that assess the aforementioned decision-making capacity abilities of a potential subject for the study (Karlawish, J., 2003).
Research protocols should describe how assessment of subject decision-making capacity will be done. The extent of the assessment should correlate with the risks of the research. For minimal risk studies, an informal assessment by a research team member should suffice. For higher risk studies, using an independent qualified professional skilled in assessing decision-making capacity should be considered (Alzheimer's Association, 2004).
Notably, some subjects may lose decision-making capacity during a study. If at the time of enrollment subjects have capacity to consent, but are at risk of losing capacity during the study, then investigators should describe in their protocols how periodic capacity reassessments will be done. Furthermore, investigators should offer subjects the opportunity the name a proxy decision-maker and ask the subject to provide guidance to the proxy on what to do should loss of capacity occur. In addition, some subjects with impaired capacity and enrolled in research studies via proxy consent may later regain capacity. In these situations, the investigator must obtain informed consent from the subject for continued participation (Alzheimer's Association, 2004).
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