Competence Determination in Alzheimer's Disease
Clinicians should assess capacity (not competence) in patients with suspected Alzheimer's disease by establishing a triadic clinician-patient-informant relationship from the outset, systematically evaluating the patient's understanding and appreciation of medical facts, and recognizing that capacity is task-specific and varies with the stringency of the decision being made. 1
Foundational Principles
Capacity versus competence: The physician's role is to assess capacity (a clinical determination), while competence is a legal determination made by courts. 2 Capacity refers to the patient's functional ability to understand, appreciate, and use information to make decisions about specific tasks or treatments. 1, 3
Task-specific nature: Capacity is not global—it is specific to the particular decision or action at hand. 3 A patient may retain capacity for low-risk decisions (e.g., choosing a meal) while lacking capacity for high-risk decisions (e.g., consenting to experimental treatment or major surgery). 3
Establish the Triadic Relationship Early
Begin by developing a partnership with both the patient and an informant (care partner) to establish shared goals and assess the patient's capacity to engage in goal-setting. 1 This triadic clinician-patient-informant relationship is critical because:
- Patients with cognitive-behavioral syndromes commonly have impaired awareness of their illness (anosognosia), which directly impacts their ability to provide accurate information and participate in decision-making. 1
- Informant reports provide added value beyond patient self-report and cognitive test performance in detecting clinically significant impairment. 1
- The informant should be interviewed separately when possible, as patients and care partners may have divergent opinions about symptoms and their consequences due to the patient's diminished insight. 1
Systematic Capacity Assessment Framework
Evaluate four core cognitive abilities that underlie decision-making capacity: 4, 5
1. Understanding
- Assess whether the patient can comprehend relevant information about the decision, including the nature of the condition, proposed interventions, alternatives, and consequences. 4
- Use simple auditory comprehension tasks and confrontation naming tests, as these predict capacity to evidence a treatment choice even in advanced dementia. 5
2. Appreciation
- Determine whether the patient can apply information to their own situation and recognize how it affects them personally. 1
- Word fluency measures and executive function tests predict the capacity to appreciate consequences of treatment choices. 5
3. Reasoning
- Evaluate the patient's ability to manipulate information rationally, compare options, and weigh risks and benefits. 4
- Conceptualization tasks and measures of frontal lobe function (executive dysfunction) are key predictors of reasoning capacity. 5
4. Expression of Choice
- Confirm the patient can communicate a stable choice, whether verbally, by pointing, gesture, or other means. 4
- Even patients with severe aphasia may retain capacity if they can express wishes through compensatory methods. 4
Cognitive Testing Strategy
Administer validated cognitive instruments, but never interpret scores in isolation: 1
- Brief cognitive screening (e.g., MoCA, MMSE) provides a gross estimate of impairment severity but has low predictive value for capacity determination. 3, 6
- Domain-specific testing is more informative: confrontation naming, conceptualization, word fluency, and visuomotor tracking are the strongest predictors of capacity across different legal standards. 5
- Language and executive function are the cortical functions most predictive of incapacity in Alzheimer's disease. 3
Integrate cognitive test results with comprehensive history from both patient and informant, functional assessment, and the patient's overall risk profile. 1
Legal Standards Framework
Match the level of required capacity to the stringency of the decision: 5
- Minimal standard (LS1): Capacity to evidence a treatment choice—requires only basic comprehension and ability to communicate. Loss of this capacity occurs in advanced dementia and is predicted by severe receptive aphasia and dysnomia. 5
- Moderate standard (LS3): Capacity to appreciate consequences of a choice—requires executive function and reasoning. Loss occurs in mild-to-moderate dementia and is predicted by executive dysfunction. 5
- Stringent standard (LS5): Capacity to understand the treatment situation and choices—requires intact conceptualization, semantic memory, and verbal recall. Loss occurs in mild dementia and is predicted by deficits in conceptualization and confrontation naming. 5
Structured Assessment Process
Follow this algorithmic approach: 1
Obtain comprehensive history from patient and informant separately, characterizing cognitive symptoms, behavioral changes, functional decline, and temporal course. 1
Assess awareness and insight by comparing patient and informant reports—significant discrepancies suggest anosognosia and reduced capacity. 1
Perform validated cognitive testing with emphasis on language (comprehension, naming), executive function (conceptualization, word fluency), and memory domains. 1, 5
Evaluate functional abilities using validated instruments (e.g., FAQ, DAD) to determine impact on activities of daily living. 7
Apply task-specific capacity assessment using the four-step framework (understanding, appreciation, reasoning, expression) matched to the stringency of the decision. 4, 5
Identify compensatory abilities that may bypass deficits—patients with language impairment may retain capacity if they can communicate through alternative means. 4
Document findings including specific cognitive deficits, preserved abilities, and the rationale for capacity determination. 1
Common Pitfalls to Avoid
Do not assume incapacity based solely on diagnosis or cognitive test scores. 1, 3 MMSE scores have low predictive value for capacity, and patients with mild dementia may retain capacity for many decisions. 3
Do not apply a global standard of capacity. 3 Assess capacity separately for each specific decision or task—a patient may lack capacity for complex financial decisions while retaining capacity to consent to routine medical care. 3
Do not rely on patient self-report alone. 1, 7 Patients with dementia lack insight into their deficits and cannot reliably report their own functional or cognitive changes. 7
Do not overlook preserved cognitive functions. 4 Conduct detailed assessment for compensatory abilities that can bypass deficits before concluding a patient is incapacitated. 4
Do not confuse capacity with agreement. A patient who disagrees with the clinician's recommendation is not necessarily incapacitated—capacity assessment focuses on the process of decision-making, not the outcome. 1
Longitudinal Monitoring
Reassess capacity periodically as dementia progresses, particularly when new high-stakes decisions arise or when functional decline is observed. 7 Loss of competency is inevitable in progressive dementia, but the timeline varies by individual and by the specific capacity being assessed. 8, 2
Engage care partners early in the communication and decision-making process, even when the patient retains capacity, to establish a foundation for future care planning as capacity declines. 1