Capacity to consent to research in older adults with normal cognitive functioning, mild and major neurocognitive disorder: an Italian study

Background: A specific evaluation of the capacity to consent to research in older adults with cognitive decline is often not included routinely in research practice. However, there is a need to evaluate this competence adopting brief standardized instruments to guarantee their ethical rights. The present study evaluated in older adults with normal cognitive functioning, and major and mild neurocognitive disorders whether the Mini-Mental State Examination (MMSE) and a brief battery of neuropsychological tests are sensitive and specific to discriminate subjects able to provide consent to research. Methods: 54 participants with Major Neurocognitive Disorder (MajorNCD), 22 with Mild Neurocognitive Disorder (MildNCD), and 37 Normal Cognitive Functioning individuals (NCF). The capacity to provide consent was assessed using the MacArthur Competence Assessment Tool for Clinical Research. Cognitive functioning was assessed using the MMSE, Verbal Fluency Tests, Trail Making Test (TMT-A), Immediate and Delayed Recall Test. Results: In the MildNCD and NCF groups, the aggregate score of neuropsychological tests showed high sensitivity and specificity in classifying subjects able to provide consent to research. In the MajorNCD group, MMSE, Recall test, and TMT-A performed better than the aggregate score in classifying subjects as able of consenting to the hypothetical research. Conclusion: The choice of the best tool to assess the ability to provide consent to research may depend on the degree of cognitive impairment. MMSE is a good tool for subjects with MajorNCD. A more comprehensive battery of neuropsychological tests would represent a better tool in NCF and MildNCD individuals.