Blood Biomarker May Signal Memory Vulnerability Years Before Cognitive Changes

By: Staff Writer | September 10, 2026 | 9 min. read |

In a study of 1,170 older adults, Miller School researchers found that higher p-tau181 blood levels were associated with poorer memory performance six years later, even when no memory association was detected at baseline.

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Key Takeaways

Miller School researchers analyzed blood samples and cognitive data from 1,170 older adults, with cognitive assessments conducted six years apart.
Higher levels of p-tau181 were not associated with memory performance at the initial assessment but were linked to poorer memory performance six years later.
Different blood biomarkers were associated with different aspects of cognition, underscoring the value of examining specific cognitive abilities rather than relying only on an overall score.
The findings cannot predict whether a specific individual will develop Alzheimer’s disease, mild cognitive impairment or dementia. Additional research is needed before the results can inform individual risk assessment.

A blood test marker linked to Alzheimer’s disease may reveal subtle signs of future memory vulnerability long before memory problems can be detected through standard cognitive testing, according to new research from the University of Miami Miller School of Medicine.

The findings suggest that blood-based biomarkers could help researchers better understand who may be at greater risk for future cognitive decline, even among older adults who appear cognitively normal today.

In a study published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, James Galvin, M.D., M.P.H., professor of neurology at the Miller School, chief of the Division of Cognitive Neurology, founding director of the Comprehensive Center for Brain Health and director of the Lewy Body Dementia Research Center of Excellence, and Deirdre O’Shea, Ph.D., assistant professor of cognitive neurology at the Miller School, analyzed blood samples and cognitive data from 1,170 older adults participating in the Health and Retirement Study Harmonized Cognitive Assessment Protocol, a population-based study of older U.S. adults.

Dr. James Galvin, standing and smiling, wearing a white medical coat — Dr. James Galvin is founding director of the Comprehensive Center for Brain Health. (Photo by Isabella Frias)

Dr. O’Shea and Dr. Galvin examined whether levels of several Alzheimer’s-related blood biomarkers were associated with cognitive performance at the time of testing and six years later.

p-tau181 and Memory

Rather than categorizing participants as biomarker-positive or biomarker-negative, the researchers analyzed biomarker levels across their full measured range. They focused on four emerging blood markers associated with Alzheimer’s disease and neurodegeneration:

Phosphorylated tau 181 (p-tau181)
Glial fibrillary acidic protein (GFAP)
Neurofilament light chain (NfL)
Amyloid beta 42/40

They then compared those measures with performance in specific cognitive domains, including memory, executive function, language, visuospatial ability and overall cognition.

The study population had an average age of 73. Participants completed extensive cognitive evaluations in 2016 and again in 2022. At the start of the study, 931 participants were cognitively normal, 206 had mild cognitive impairment and 33 had dementia.

Frequently Asked Questions

What is p-tau181?

P-tau181 is a blood biomarker associated with Alzheimer’s-related changes in the brain and is being studied as an indicator of neurodegeneration.

What did the researchers discover?

Higher p-tau181 levels were associated with poorer memory performance six years later, even when memory appeared normal at the time blood samples were collected.

Can this blood test predict who will develop Alzheimer’s disease?

No. The study identified population-level associations but was not designed to predict whether a specific person will develop Alzheimer’s disease, mild cognitive impairment or dementia.

Why Examine Biomarkers and Cognitive Abilities on a Continuum?

One of the most notable findings involved p-tau181, a biomarker increasingly viewed as a promising indicator of Alzheimer’s-related brain changes. Researchers found that p-tau181 was not associated with memory performance when blood samples and cognitive testing were conducted at the same time. Yet higher p-tau181 levels were linked to poorer memory performance six years later, even after accounting for individuals’ memory abilities at baseline and the other biomarkers.

“p-tau181 was not associated with memory at the initial assessment, but it was associated with memory performance six years later,” said Dr. O’Shea. “That suggests these blood markers may provide information about future cognitive vulnerability that is not apparent from cognition measured at the same point in time.”

University of Miami Miller School of Medicine's Deidre O'Shea, in white collared shirt — Dr. Deidre O’Shea says “blood markers may provide information about future cognitive vulnerability.”

The findings also show why the relationship between blood biomarkers and cognition may depend on when and how cognition is measured. While researchers often evaluate biomarker performance using overall cognitive scores, this study examined memory, executive function, language and visuospatial ability separately, revealing patterns that might otherwise remain hidden.

“Blood biomarkers are often discussed as positive or negative tests, but biology exists on a continuum,” Dr. O’Shea said. “By examining biomarker levels across their full range and looking separately at memory, executive functioning and other cognitive abilities, we could see patterns that would be lost by reducing either the biomarker or cognition to a single category.”

The analysis revealed that different biomarkers were associated with different aspects of cognition. At baseline, NfL and GFAP showed the broadest associations, correlating with memory, executive function and global cognition. Six years later, however, p-tau181 remained independently associated with lower memory and global cognition, while GFAP was linked to poorer memory, executive function and overall cognition. NfL and amyloid beta 42/40 were no longer independently associated with cognitive outcomes after those adjustments.

Researchers also found evidence that p-tau181 may be more closely tied to memory than to executive function, a distinction that aligns with the early cognitive profile often seen in Alzheimer’s disease. Notably, the primary findings remained largely unchanged when analyses were restricted to participants who were cognitively normal at the start of the study.

Can a Blood Test Predict Alzheimer’s Disease?

The work adds to growing interest in blood-based biomarkers as scalable tools for studying Alzheimer’s disease in large populations. Blood tests are less invasive and more accessible than brain imaging or spinal fluid collection. Researchers hope they may eventually play an important role in identifying people who could benefit from closer monitoring or future interventions.

Dr. O’Shea cautions that the study was not designed to predict whether a specific individual will develop Alzheimer’s disease, mild cognitive impairment or dementia. The biomarker associations explained only modest amounts of additional variation beyond established risk factors and baseline cognitive performance. Additional studies with repeated blood testing and longer-term follow-up will be needed before these findings can be translated into individual risk assessment.

Still, the results suggest that subtle biological changes detectable in a blood sample may precede measurable memory changes by years. For researchers seeking earlier ways to understand Alzheimer’s disease progression, that window could provide valuable insight into the earliest stages of cognitive vulnerability.