One dose of a new treatment, delivered by nasal spray, clears away build-ups of the toxic tau protein associated with Alzheimer’s disease from inside brain cells, improving memory, according to new research. It paves the way for new treatments for the debilitating disease.A few years ago, abnormal clumps of tau proteins in the brain were found to be associated with Alzheimer’s disease. Since then, researchers have been working on a way of eradicating these toxic tangles, which have become a hall...