Preservation of the capacity to appoint a proxy decision maker: implications for dementia research.

CONTEXT

Research involving persons with impaired decision-making capacity (such as persons with Alzheimer disease [AD]) remains ethically challenging, especially when the research involves significant risk. If individuals incapable of consenting to research studies were able to appoint a research proxy, it would allow for an appointed surrogate (rather than a de facto surrogate) to represent the subject.

OBJECTIVE

To assess the extent to which persons with AD retain their capacity to appoint a research proxy.

DESIGN

Interview study.

SETTING

Academic research.

PARTICIPANTS

One hundred eighty-eight persons with AD were interviewed for their capacity to appoint a proxy for research and to provide consent to 2 hypothetical research scenarios, a lower-risk randomized clinical trial testing a new drug (drug RCT) and a higher-risk randomized clinical trial testing neurosurgical cell implants using a sham control condition (neurosurgical RCT). Categorical capacity status for each subject was determined by independent videotaped reviews of capacity interviews by 5 experienced psychiatrists.

MAIN OUTCOME MEASURES

Categorical capacity determinations for the capacity to appoint a research proxy, capacity to consent to a drug RCT, and capacity to consent to a neurosurgical RCT.

RESULTS

Data showed that 37.7% (40 of 106) of those deemed incapable of consenting to the drug RCT and 54.8% (86 of 157) of those deemed incapable of consenting to the neurosurgical RCT were found capable of appointing a research proxy. Only 7 of 186 (3.8%) were deemed capable of consenting to the neurosurgical RCT by all 5 psychiatrists.

CONCLUSIONS

A substantial proportion of persons with AD who were thought incapable of consenting to lower-risk or higher-risk studies have preserved capacity for appointing a research proxy. Because few persons are found to be unequivocally capable of providing independent consent to higher-risk AD research, providing for an appointed surrogate even after the onset of AD, which might best be done in the early stages of the illness, may help address key ethical challenges to AD research.