In cognitively healthy adults, more frontal tau lined up with shorter deep-sleep waves and weaker overnight memory

What the research found

ScienceDaily published this account on 5 November 2026. The Nature Neuroscience paper, DOI 10.1038/s41593-026-02415-9, went online on 11 September 2026 and is in the November 2026 print issue. Omer Sharon, Matthew Walker, and colleagues at UC Berkeley compared deep-sleep brain waves in cognitively healthy young adults in their early 20s with older adults from the mid-60s to the mid-70s. In the younger group, slow waves traveled together across a distance about the width of a hand on the scalp. In the older group, the waves traveled less far and showed up more on their own. Positron emission tomography with William Jagust linked more tau in the frontal cortex with that breakdown. The people did not have Alzheimer's disease, and their memory change was inside the usual range for their age. Those whose waves traveled less far remembered fewer word pairs learned the night before. In a separate spinal-fluid group with Yo-El Ju, more isolated slow waves lined up with a higher tau-to-amyloid ratio. A subset followed for several years showed tau, wave breakup, and overnight forgetting rising together. The account does not give the sample size, and it does not show which change comes first. Not medical advice.

Evidence level: Human study. A study in people, but an association isn't proof of cause.

Read the original at ScienceDaily