Declining medical decision-making capacity in mild AD: a two-year longitudinal study

This is a report of a two‐year longitudinal study comparing healthy older adult subjects (n = 15) and mild Alzheimer's disease (AD) patients (n = 20) using an objective performance measure of medical decision‐making capacity (MDC). Capacity to consent to medical treatment was measured using the Capacity to Consent to Treatment Instrument (CCTI). The CCTI is a psychometric measure that tests MDC using a series of four core capacity standards: S1 (evidencing/communicating choice), S3 (appreciating consequences), S4 (providing rational reasons), and S5 (understanding treatment situation), and one experimental standard [S2] (making the reasonable treatment choice). For each standard, mild AD patients were assigned one of three capacity outcomes (capable, marginally capable, or incapable) based on cut‐off scores derived from control group performance. At baseline, mild AD patients performed equivalently with controls on simple standards of evidencing a choice (S1) and making the reasonable choice ([S2]), but significantly below controls on complex standards of appreciation, reasoning, and understanding (S3, S4, and S5) (p