Mild Cognitive Impairment (MCI) has been proposed as a middle ground between normal aging and dementia, and this concept holds promise for the early identification and treatment of individuals likely to develop Alzheimer's disease (AD). 1 limitation of the predictive value of this concept is that only a fraction of individuals with MCI go on to develop AD each year (approximately 12%). If the individuals who convert from MCI to AD were more easily identified, then clinical trials could be more efficiently conducted. Since no specific biomedical/psychometric marker is available that identifies these potential converters, the present study seeks to utilize a novel paradigm to identify these individuals who are at greater risk to convert to AD. 1 goal of this project is to determine the relative magnitude of practice effects (i.e., increased cognitive test performance due to repeated exposure to test materials) among elderly individuals with no cognitive impairments (NCI) or MCI. Recently, practice effects have been shown to be useful in detecting MCI, and a logical extension of these findings is to evaluate their ability to predict decline in MCI. Therefore, a second goal is to determine the relative value of practice effects in predicting future cognitive functioning. Specifically, we propose a longitudinal observational study in elderly subjects with NCI or MCI. All participants will receive a baseline assessment of cognitive functioning, which will be immediately repeated to assess practice effects. It is expected that participants with NCI will demonstrate larger practice effects than participants with MCI. It is also expected that within the MCI group, some individuals will display relatively larger practice effects and some will display smaller practice effects. Follow-up cognitive evaluations will be conducted on all participants at 6- and 12-months. It is hypothesized that the amount of practice demonstrated during the baseline phase will be inversely related to the amount of cognitive decline on follow-up, which could lead to earlier identification of cognitive decline.
