Tau malfunction causes Alzheimer's.
A new analysis ... has singled out malfunctioning tau proteins as the main driver for the cognitive decline and memory loss associated with Alzheimer's disease,...
They created a timeline for the disease’s progression using these brains, and came up with a way to quantify the progression of defective amyloid and tau build-up along the way.
Next, they analysed brain scans taken of amyloid protein clusters in patients prior to death and compared these to the measures they took from the post-mortem brain examinations. Together, these analyses revealed that the severity of tau - not amyloid - malfunction predicted age-related onset of cognitive decline, mental deterioration, and Alzheimer’s duration.
... the researchers say they found a strong link between the build-up of amyloid and a decline in cognition, but as soon as they took the severity of the tau malfunction into account, this link disappeared. And some of the brains were found to have amyloid build-up without showing signs of cognitive decline. [emphasis mine]