Without both, progressive clinical decline associated with AD in cognitively healthy older individuals is "not significantly different from zero," reports scientists at the University of California.

"I think this is the biggest contribution of our work," said Rahul Desikan, MD, PhD. "A number of planned clinical trials - and the majority of Alzheimer's studies - focus predominantly on a-beta. Our results highlight the importance of also looking at p-tau, particularly in trials investigating therapies to remove a-beta. Older, non-demented individuals who have elevated a-beta levels, but normal p-tau levels, may not progress to Alzheimer's, while older individuals with elevated levels of both will likely develop the disease."

The findings also underscore the importance of p-tau as a target for new approaches to treating patients with conditions ranging from mild cognitive impairment (MCI) to full-blown AD.

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