How is capacity assessment performed in individuals with impaired cognitive function?

Capacity Assessment in Individuals with Impaired Cognitive Function

Capacity assessment should be performed using a structured approach that evaluates four key abilities: understanding, appreciation, reasoning, and communication of choice specific to the decision at hand, with the rigor of evaluation increasing proportionally to the risk of the decision. 1

Fundamental Principles of Capacity Assessment

• All adults should be presumed to have capacity until proven otherwise 1
• Capacity is decision-specific and time-specific, not global 1
• Assessment should be triggered by evidence of potential incapacity, not simply by diagnosis 1
• Capacity evaluations should be proportionate to the risks posed by the decision 2

Components of a Proper Capacity Assessment

A structured approach to capacity assessment should evaluate:

1. Understanding: Can the person comprehend information relevant to the decision?
2. Appreciation: Can they appreciate the situation and its consequences?
3. Reasoning: Can they manipulate information rationally?
4. Communication: Can they express a choice? 1, 3

Assessment Process for Individuals with Cognitive Impairment

When to Conduct Formal Assessment

Formal capacity assessment should be considered when:

• There is an acute change in mental status
• The person refuses clearly beneficial treatment
• The person readily agrees to risky procedures without consideration
• There are risk factors for impaired decision-making 3

Assessment Tools

• MacArthur Competence Assessment Tool (MacCAT) is a validated structured interview recommended for capacity assessment 1, 4
• When using the MacCAT with clinical interview, studies show excellent interrater reliability (kappa=0.82) 4
• For minimal risk decisions, less rigorous assessment may be appropriate 2

Special Considerations for Dementia and Cognitive Impairment

• Avoid assuming lack of capacity based solely on diagnosis of dementia 2
• Capacity may fluctuate in the short and long term, especially in dementia 2
• Assessment should be tailored to the specific decision context and associated risks 2
• For conditions with fluctuating capacity, assessment should occur during periods of optimal function 2

Decision-Making When Capacity is Impaired

When a person is determined to lack capacity:

• Identify a legally authorized representative (LAR) or surrogate decision-maker 1
• The LAR should respect known wishes expressed by the person 2
• When wishes cannot be ascertained, decisions should account for the person's beliefs, values, and welfare 2
• Consider whether capacity might be regained with treatment or support 1

Monitoring Cognitive Capacity

• Cognitive capacity should be monitored throughout the lifespan for individuals with conditions that may affect cognition 2
• Particular attention should be paid to those with documented cognitive disabilities, those who experience severe hypoglycemia, very young children, and older adults 2
• When cognitive capacity changes or appears suboptimal for decision-making, referral for formal assessment should be considered 2

Common Pitfalls to Avoid

• Assuming lack of capacity based solely on diagnosis or age 1
• Determining incapacity because a patient makes an eccentric or unwise decision 1
• Failing to recognize that capacity requirements vary by task 1
• Relying solely on clinical judgment without using standardized assessment tools 5
• Not documenting the specific decision for which capacity is being assessed 3

Capacity assessment is a complex clinical skill that requires balancing respect for autonomy with protection from harm. When performed correctly, it ensures that individuals with cognitive impairment receive appropriate support in decision-making while preserving their rights and dignity.