🧠 Can a simple blood test tell us when Alzheimer's symptoms will begin?

A new Nature Medicine study introduces a plasma p-tau217 "molecular clock" that estimates time to symptom onset with an error margin of ~3–4 years. By modeling the rise of phosphorylated tau in cognitively unimpaired individuals, investigators move from predicting if to predicting when.

⏳ Implication: smarter prevention trials, earlier intervention windows, and biologically timed enrollment.

⚠️ Not ready for routine screening—but a compelling proof of concept.

The era of temporal precision in neurodegeneration may have begun.