The Impact of Specific Cognitive Impairments on the Capacity to Consent to Research

Human subjects play an important role in scientific research, especially for studying disease that cause cognitive impairments. Participants provide informed consent prior to participating in research. While cognitive impairments may impact the abilities need to provide informed consent, called consent capacity, there is little knowledge for how specific cognitive abilities impacts this process. This study examined the role of specific impairments that impact consent capacity. Normal healthy adults and patients with impairments in memory, language, or executive functions (e.g. decision-making and reasoning) read fictional research studies. Consent capacity was measured with either the MacArthur Competence Assessment Tool for Clinical Research or a new tool, the Iowa Consent Tool (ICT). Patients with impaired memory or executive functions did not differ in consent understanding but both had lower consent understanding than normal healthy adults. Being able to apply relevant information (appreciation) and reasoning varied different research scenarios, suggesting that there may be underlying characteristics of studies that could be challenging for participants. Further investigation of how the reading level of consent documents and the differing levels of risks and benefits may provide insight into these differences. This first use of the new ICT suggests that it useful for measuring consent appreciation. This research has important implications for consent with both cognitively impaired patients and healthy adults in other applications including medical treatment. Future research should examine targeted interventions to improve the consent process.