Your nose could detect Alzheimer’s years before memory loss

Researchers have uncovered why smell often fades early in Alzheimer’s: the brain’s immune cells dismantle key nerve connections between the olfactory bulb and brainstem. Membrane changes in neurons send an “eat-me” signal to microglia, which mistakenly destroy them. Evidence from mice, human tissue, and PET scans confirms this process. These insights could pave the way for earlier diagnosis and more effective treatment.