Cortical microstructural changes predict tau accumulation and episodic memory decline in older adults harboring amyloid.

People with Alzheimer's disease have problems with their memory and ability to acquire and process knowledge. Understanding the earliest brain changes leading to these problems helps identify those likely to develop Alzheimer's disease early in the disease process. This study used a marker that measures the mobility of water in the brain to investigate how these changes can predict development of a protein named tau and changes in people's memory. The participants showed no signs of memory impairment at the beginning of the study, but some developed memory decline during follow-up. Greater mobility of water in certain brain areas predicted future increase in tau and decline in memory, indicating this measure could be used to identify people at risk of developing Alzheimer's disease.