The Study
Concurrent changes in plasma p-tau217, tau PET, and cognition in preclinical Alzheimer’s disease
This study looked at how brain changes and memory scores changed over time in older people who didn’t yet have Alzheimer’s symptoms. It found that when certain brain proteins went up, memory tended to get worse — but it didn’t prove that one caused the other. It’s like noticing that people who eat more ice cream also get more sunburns — they’re linked, but ice cream doesn’t cause sunburn.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
Scientists studied older people with no memory problems but early Alzheimer’s brain changes to see if blood and brain scans could predict when they might start forgetting things.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 552 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — this means a simple blood test could help identify people at high risk of memory loss years before they show symptoms, and brain scans can show if decline is happening right now.
- 2Blood test for p-tau217 rises 1.19x over 3 years before slowing down.
- 3Brain scans show tau buildup in the entorhinal cortex best predicts future memory loss (correlation −0.55).
- 4Tau in frontoparietal areas tracks with current memory changes (up to −0.68).
- 5Blood test didn’t match current memory changes in the brain-scan group, but did in the bigger group.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
JAMA neurology
Year
2025
Authors
P. Insel, N. Mattsson‐Carlgren, O. Langford, Vincent M. Caruso, A. Leuzy, Christina B. Young, A. Boxer, P. Aisen, Reisa A. Sperling, Elizabeth C. Mormino, M. Donohue
Related Content
Claims (6)
Phosphorylated tau protein can be detected in the brain using neuroimaging techniques 12 years before a person shows any signs of Alzheimer's disease.
In older adults with early-stage Alzheimer’s disease, levels of phosphorylated tau 217 in the blood rise steadily over time, slow down after 36 months, and this pattern corresponds to an early phase of tau protein changes that stabilize before extensive brain damage occurs.
In older adults showing early signs of Alzheimer’s disease before symptoms appear, higher levels of tau protein in the entorhinal cortex measured by PET scan are consistently linked to greater future decline in memory and thinking skills, more so than tau in other brain areas or tau levels in the blood.
In older adults with early signs of Alzheimer’s disease and high amyloid levels, higher amounts of phosphorylated tau 217 in the blood are linked to a 47% faster rate of cognitive decline over several years, as measured by the Preclinical Alzheimer Cognitive Composite.
In older adults showing early signs of Alzheimer’s disease before symptoms appear, increased tau protein buildup in specific brain regions is directly associated with measurable declines in cognitive performance at the same time.
In older adults with early signs of Alzheimer’s disease, changes in plasma phosphorylated tau 217 levels are not linked to immediate changes in cognitive performance when measured alongside brain tau scans, but are weakly linked to cognitive changes when measured without brain scans, suggesting that blood biomarker changes occur before cognitive effects become detectable.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.