Grant: Travel Awards - Institute Community Support

Individuals with mild cognitive impairment (MCI) or late-life depression (LLD) are known to be at risk for Alzheimer's disease (AD). However, it is unclear as to which clinical characteristics predict the occurrence of AD for each condition. Although MCI and LLD have been rigorously described individually, few studies have investigated the characteristics shared by both conditions. Nonetheless, there are many overlaps in the brain regions affected in MCI and LLD. These brain lesions have otherwise been associated with cognitive decline and progression towards AD. Furthermore, both conditions frequently coexist, as it is when patients with MCI also present depressive symptoms (MCI/D+), which is true for a great proportion of patients. This project aims to identify and compare the common and specific characteristics (e.g., brain lesions) amongst different groups of at risk participants. We recruited a cohort of participants presenting either MCI, MCI/D+, or LLD. All participants had a brain scan at baseline in order to locate and quantify the lesions. Subsequent analyses compared the lesions between the three groups. The results revealed that overall, MCI/D+ participants had more severe lesions in many brain regions but that these lesions were significantly more important than those in MCI participants in one region: the hippocampus. The results also revealed there was no difference between the LLD participants and the two other groups in those same regions. These findings contribute to better understanding the clinical differences between diverse at risk groups of patients. Further research should investigate the impact of such differences on future risk of progression towards AD.