ASSESSING TREATMENT DECISION-MAKING CAPACITY IN ELDERLY NURSING-HOME RESIDENTS

Clinicians usually employ indirect measures of cognitive and physical function in order to assess medical decision‐making capacity. We tested a reference group of well elderly (Mini‐Mental State Exam [MMSE] score = 29.1 ± 0.8, mean ± SD), for their understanding of three increasingly complex, hypothetical treatment situations or “vignettes”—use of a hypnotic, need for thoracocentesis, and desire for CPR. From this, we have developed a more direct, Guttman‐like assessment of decision‐making capacity. Of 51 Veterans Affairs nursing home residents (MMSE score = 22.4 ± 6.9), only 33.3% demonstrated intact decision‐making capacity by this method, whereas 77% were felt by their primary physicians to be capable of giving consent for oral surgery; 37.3% had very impaired decision‐making capacity; and 29.4% were intermediate in this ability. Judged against our more direct assessment of decision‐making capacity, primary physicians' judgment of capacity for consent was 31% to 39% sensitive in identifying impaired decision‐making and the MMSE was 53% to 63% sensitive. These measures were 100% and 82% to 83% specific in identifying intact decision‐making capacity, respectively. We conclude that (1) more directly assessed decision‐making capacity varies noticeably among elderly nursing home residents and correlates in only limited fashion with frequently used cognitive screening methods; and (2) cognitive screening tests underestimate the prevalence of impaired decision‐making capacity in this population. For informed consent and advance directives, our study suggests that decision‐making capacity should be directly, rather than indirectly, assessed. © 1990 The American Geriatrics Society