PhD defence A.M. (Anna) Streiber

Below is a brief summary of the dissertation

This thesis explores how hardening and narrowing of the brain’s arteries, known as intracranial arteriosclerosis, may contribute to Alzheimer’s disease and cognitive decline. Although both conditions are common and serious, the biological links between them are still not well understood.
First, I studied whether arteriosclerosis affects how well vessels in the brain work and whether it contributes to buildup of amyloid β, a key protein in Alzheimer’s disease. I found that arteriosclerosis increases pulsatility (a measure of how well blood flows though a vessel) in nearby large brain arteries, but it does not seem to impair the smaller vessels deeper in the brain. I also found no consistent connection between small vessel function and amyloid β, except that faster blood flow in certain deep brain regions may reflect the brain compensating for early amyloid changes.
Next, I examined whether arteriosclerosis is linked to Alzheimer’s-related biomarkers in the brain and blood. My findings show that arteriosclerosis and brain amyloid β likely contribute to Alzheimer’s disease independently. Arteriosclerosis may contribute to Alzheimer’s disease through other pathways involving nerve cell damage and vascular amyloid β.
I also investigated how arteriosclerosis affects cognitive abilities such as memory and attention over time. People with more severe arteriosclerosis performed worse at the start, and arteriosclerosis closer to the brain predicted faster cognitive decline, especially during the first five years of follow-up.
Finally, I developed practical recommendations to improve the reproducibility of statistical code in medical research, emphasizing clarity, transparency, and collaboration.