Assessment of Decision-Making Capacity

Eric S. Swirsky

INTRODUCTION

The shared decision-making paradigm reflects the importance of patient autonomy in clinical encounters. Respect for patient autonomy requires that individuals have the right to accept or refuse recommended interventions, even those that are potentially lifesaving. The process of providing adequate disclosure of information to and receiving informed consent from patients is aimed at satisfying this clinical duty; however, a patient’s mental capacity and legal competence to comprehend and evaluate complex information and communicate choices are both prerequisites. Adult patients are generally presumed to have decision-making capacity; patients with brain injuries should be formally assessed—capacity should not be inferred from the diagnosis alone. In the absence of capacity, clinicians are guided to identify an advance directive or surrogate decision maker.

GENERAL PRINCIPLES

Definitions

• Advance directive is a written or oral statement of desired medical treatment or medical decision maker, made for a future event of incapacitation; these include living wills, durable powers of attorney for health care, and Do Not Resuscitate orders. In addition, some states offer the Provider Order for Life Sustaining Treatment (POLST) or Medical Order for Scope of Treatment (MOST) that record patient wishes differently than advance directives.

• Autonomy is derived from a number of theories and represents a bundle of rights, both positive and negative, including an individual’s right to make choices about her or his health care and take actions based upon personal values and beliefs. Respect for autonomy, at a minimum, requires that a patient’s decisions and actions not be subject to outside constraints and that adequate information be disclosed for people to make informed choices [1].

• Capacity is a medical term that refers to a patient’s functional ability to make decisions regarding her or his health care and provide informed consent for treatment. Determinations of patient capacity are made by qualified clinicians. Patients may be referred to as being “decisional,” “incapacitated,” or as having/lacking “decisional capacity” or “decision-making capacity.”

• Competency is a concept that refers to the legal decision-making status of a patient, which is formally determined by a court of law. In practice and literature the terms capacity and competency are often used interchangeably; however, the concepts have different processes and implications for patients and providers. For example, patients adjudged to be incompetent by the courts will have a decision maker appointed (a legal guardian) and they may lose certain rights such as the right to vote, the right to marry, and the right to enter into contractual agreements.

• Surrogate is a health care decision maker identified by the provider if it is determined that the patient lacks capacity and has no advance directive.

Epidemiology

• The prevalence of incapacity varies by patient population. For example, a meta-analysis of assessment instruments suggests that 54% of patients with Alzheimer’s disease, 44% of nursing home patients, 26% of medical inpatients, and 20% of patients with mild cognitive impairment lacked decision-making capacity [2].

• Evidence suggests that physicians routinely fail to recognize the incidence or level of incapacity, thus prevalence may be impossible to quantify. A review of studies reporting physician recognition of capacity found that physicians correctly identified incapacity in about 42% of patients whose lack of capacity was independently judged [2].

Fundamental Principles of Decision-Making Capacity

• Health care decision making requires a constellation of capacities. The four most commonly assessed are a patient’s abilities to understand relevant information, appreciate the consequences of the situation, reason through treatment decisions, and communicate choices [3]. Another commonly cited factor is the possession and expression of a set of values and goals [4].

• It is presumed that every adult patient has capacity unless proven otherwise; however, in at least one state this presumption is reversed in certain circumstances. In New York, when there is medical evidence of a mental illness or defect the patient is presumed to lack capacity, and the burden shifts to the patient to prove she or he has capacity [5].

• Patients with decision-making capacity have the ability to act autonomously and provide informed consent for or refuse medical interventions. The right to refuse unwanted medical treatment is constitutionally protected; however, some laws may require “clear and convincing evidence” when relying upon an incapacitated patient’s previously stated wishes [6].

• Decisional capacity is not static. For example, a patient’s capacity may wax and wane and can be influenced by mood, time of day, metabolic status, fatigue, pain, medications, infections, and psycho-social factors. If a patient’s capacity can be optimized to a point where she is decisional, then her capacity should be reassessed [2].

• Refusal of treatment alone should not be considered a sign of incapacity; however, patients who disagree with recommended interventions and are less compliant are more likely to have providers challenge their capacity. In assessing capacity, providers should focus on how patients arrive at a decision rather than the decision itself.

ASSESSING CAPACITY

Background

• Ability to assess decision-making capacity is described as a “core competency” in brain injury rehabilitation [7]; however, it is not an area in which most clinicians are well trained or experienced [8].

• Patients with brain injuries (along with the elderly, patients with mental illness, mental retardation, and aphasia) should receive formal assessments of their capacity. They should not be deemed to be incompetent based solely on their medical diagnosis or condition.

• There is no universally accepted clinical method of assessing a patient’s decisional capacity [9]. Similarly, the U.S. court system has yet to articulate a universal standard for determining competence, as most states have their own statutory definitions.

• Assessment of decisional capacity is decision-specific. A patient may have capacity to make some decisions, such as who she wants as surrogate decision maker, but remain unable to make more complex decisions related to care. When assessing capacity, the clinician should explicitly state which decision is being tested (i.e., “this patient is being assessed for her ability to make decisions about having a shunt revision this week to relieve intracranial pressure”).

• It is generally accepted that capacity should be assessed on a sliding scale: the level of capacity required changes in proportion to the complexity and gravity of the decision and risk to the patient [10].

• Most traumatic brain injuries (TBIs) are mild in degree, and most of these patients regain their decisional capacity within a matter weeks. However, patients with more severe TBIs have to also demonstrate partial or full recovery of decisional capacity over time, thus underscoring the importance of assessing capacity in temporal proximity to the injury [11].

• Unstructured evaluations of capacity are considered unreliable [12]; therefore, a number of evaluation tools have been developed to help clinicians and researchers identify incapacitated patients.

Assessment Instruments and Protocols

The following is a sample of some of the existing assessment tools available. It is important to note that instruments should be selected based on context of use, that each instrument has limitations, and that the various tools do not always agree in assessment of decisional capacity [13].

• Aid to Capacity Evaluation (ACE). An assessment tool, available online, developed by the University of Toronto Joint Center for Bioethics [14].

• Capacity to Consent to Treatment Instrument (CCTI). An instrument that asks patients to respond to hypothetical oral and written vignettes in order to determine general capacity to consent to medical treatment [15].

• Hopkins Competency Assessment Test (HCAT). A brief method for evaluating patients’ capacity to provide informed consent based on a short essay and a questionnaire [16].

• MacArthur Competence Assessment Tool for Treatment (MacCAT-T). A guide developed by Applebaum and Grisso to assist clinicians in rating responses during a structured assessment interview (see the following) [17]. There is also a version for assessing capacity for clinical research (MacCAT-CR), which can be tailored to individual protocols [18].

• Mini-Mental Status Examination (MMSE). A method of grading cognitive impairment in clinical and research settings [19]. Although widely used it is of questionable utility as a stand-alone capacity assessment tool, and it is recommended that it be used in concert with other assessment methods [12,15].

The Structured Interview

The Decisional Capacity Structured Interview. Whether or not a specific tool is used to rate the patient’s responses, assessing capacity involves a structured conversation or interview between a clinician and the patient. The following elements should be considered:

• Alertness: Patients must have a level of alertness that allows for the assessment to take place. Comatose and vegetative patients are easily adjudicated and are universally viewed as incompetent; however, recent advances in neuroimaging may provide for a novel approach for determining the awareness of neurologically impaired and behaviorally nonresponsive patients [20].

• Orientation: Assess orientation to situation and appreciation of the need to participate in decision making. Assessment may include questions pertaining to orientation from the Mini-Mental Status Examination.

• Ability to communicate a choice: Patients must be able to express a preference via verbal or nonverbal means. They cannot have a level of ambivalence so extreme that choices cannot be determined. Stability of choice is relevant and can be tested by asking the same questions at different times/days.

• Understanding of relevant information: Includes the ability to comprehend, store, recall, and interpret information. Deficits in intelligence, memory, and attention span can interfere with this element. Clinicians can test understanding by asking the patient to paraphrase what they have been told about the treatment or life decision.

• Appreciation of the situation and its consequences: Can the patient grasp the probable outcomes of the treatment and the consequences of its refusal? Pathological denial, delusional perceptions, and affective/cognitive deficits may interfere with this ability.

• Rational manipulation of information: Can the patient engage in a risk/benefit analysis? This involves the ability to reach conclusions that are logically consistent with the starting premise. The chain of reasoning and not the conclusion should be the focus.

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