Olfactory dysfunction in AD: A fading sense of smell can be one of the earliest signs of Alzheimer's disease even before cognitive impairments manifest https://www.nature.com/articles/s41467-025-62500-8 Brain's immune response linked to olfactory problems associated with Alzheimer's https://medicalxpress.com/news/2025-08-brain-immune-response-linked-olfactory.html