Measuring decisional capacity: Cautions on the construction of a "capacimeter."

Abstract

In their work on the MacArthur Treatment Competence Study, Paul Appelbaum, Thomas Grisso, and their colleagues warn that their "experimental measures" of decisional capacity "should not be interpreted as though they provide determinations of legal incompetence to consent to treatment." The authors of this article do not believe that Appelbaum et al.'s admonition is strong enough, and they identify and analyze the serious generic, inherent problems connected with any attempt to construct a universally acceptable version of a capacimeter. They suggest that the continuing search for the elusive "Holy Grail" test of capacity proceed with great caution (if at all), and they conclude by urging that investigators and scholars devote their energies toward the development and dissemination of appropriate clinical practice parameters.In the United States 1 at the end of the 20th century, medical decision making is predicated on the legal doctrine, 2 as well as the ethical principle, 3 of informed consent. The informed consent doctrine, in turn, is based on the assumption of a decision-making process that is voluntary, that is informed by an adequate disclosure of information to the patient or surrogate decision maker, and that involves an ultimate decision maker who has adequate cognitive and emotional capacity 4 to

Assessing Decisional Capacity for Clinical Research or Treatment: A Review of Instruments

“…There is some controversy over what the appropriate content should be for decisional capacity assessment instruments and over the determinative weight the various components of decisional capacity should carry (10,13,22,23). Moreover, different legal jurisdictions use different standards, which further complicates decisions on what standards to include in an instrument (8,11). We examined whether each instrument's constructs appeared to be consistent with widely accepted theory on competency and capacity (2,8,24 (31,32,36), cancer (33), HIV (37), and diabetes (36); control subjects (31,34) Content based on four-component model of capacity.…”

“…These capacities may be reduced by cognitive impairment, certain psychiatric symptoms, and situational factors such as the complexity of the information disclosed and the manner of disclosure (4)(5)(6). Thus, it is fundamental to the notion of capacity that different contexts may demand different kinds or levels of functional abilities (2,(7)(8)(9)(10)(11)(12). A lower level of decisional capacity is required for low-risk than a higher-risk treatment or research protocol, although it has not been clearly established what levels are appropriate for what decisions.…”

“…In treatment settings, formal capacity assessment has traditionally come into consideration when a patient refuses a recommended treatment (3,10,11,13), although it may increasingly arise in other circumstances as physicians perceive themselves to be vulnerable to lawsuits from dissatisfied patients. In the research context, the main focus has been on how to implement informed consent for studies that enroll subjects who are at risk of having impaired decisional capacity.…”

Assessment of Decision-Making Capacity in Older Adults: An Emerging Area of Practice and Research

“…They are meant to supplement but not supplant clinical judgment about capacity. Because of the interactive and contextual nature of capacity, a test score alone (Kapp & Mossman, 1996). A significant challenge in the development of such instruments is that there is no generally accepted criterion validity standard for capacity.…”

Australian lawyers' views on competency issues in older adults

“…However, the assessment of the capacities a person requires to be competent is usually determined by health professionals (Verma & Silberfeld, 1997). Issues involved in assessing the capacity of people with dementia have been identified and procedures for assessing capacity have been developed for decision-making by older people in the context of research (Berg, Karlinsky, & Lowy, 1991;Marson, Schmitt, Ingram, & Harrell, 1994), specific legal decisions (Grisso, 1987;Spar & Garb, 1992), and decisions relating to medical care (Kapp & Mossman, 1996;Park, Morrell, & Shifrin, 1999). Kapp (1990) provides a summary of various methods that have been used to evaluate decision-making capacity in older people.…”