DESCRIPTION (provided by applicant): This pilot study aims to determine the parameters and neurocognitive correlates of decision making capacity to provide informed consent for research participation among individuals with mild cognitive impairment (MCI). Individuals with MCI lack traditionally defined functional decline; however, there have been no studies examining their decisional capacity, which reflects a higher-level instrumental activity of daily living. Individuals with MCI have circumscribed cognitive impairments, making them a useful model for studying the relationship between isolated cognitive deficits and decisional capacity. The proposed pilot study uses a cross-sectional design including participants with MCI, Alzheimer's disease, and healthy, elderly controls. All participants will complete a neuropsychological protocol in conjunction with a well-known instrument of decisional capacity related to providing informed consent for research participation in a hypothetical treatment study. Between-group comparisons will be conducted for decisional capacity performance and comparisons between decisional capacity and neuropsychological test performance will be made. Data from this study will provide information regarding the parameters of MCI patients' decisional capacity for research participation with implications for other types of important decisional capacity (e.g., regarding financial and medical treatment). Unique relationships between neuropsychological functioning and dimensions of decisional capacity will be applicable in the conduct of future research. First, information related to decisional capacity-cognitive relationships will assist in the identification of other neuropsychological populations "at risk" for compromised capacity. Second, information regarding the cognitive domains most important for capacity will assist future investigators in implementing targeted interventions for remediation of compromised decisional capacity.