Project 455052

Alzheimer's disease affects the brain years, if not decades, before symptoms emerge. As such, we want to find factors that reduce later symptom severity. Here, we will investigate reduced sociality as one of those factors. Past work showed that greater social isolation predicted cognitive declines such as poorer memory - a symptom of Alzheimer's disease. However, social isolation can be defined objectively (e.g., how many social interactions someone has) and subjectively (e.g., how lonely someone feels). This work will investigate which is more influential on Alzheimer's disease progression. With this knowledge, we can develop more precise interventions before symptoms occur to buffer against later negative impacts of Alzheimer's disease. To do so, we will conduct analyses on existing data from individuals at high-risk for developing Alzheimer's disease. These participants did not have symptoms at baseline but later developed them over annual evaluations. Each year, participants completed measures of social isolation, cognition, neuroimaging, and Alzheimer's pathology. We will test whether older adults who experience greater social isolation at baseline have worse cognition when they are diagnosed with Alzheimer's disease. We predict that subjective versus objective social isolation will predict greater cognitive decline. Follow-up analyses will examine how changes in subjective social isolation affect brain function and Alzheimer's pathology. Taken together, this work will make significant scientific and translational contributions by identifying modifiable risk factors for the more rapid development of Alzheimer's disease symptoms.