Alzheimer’s EEG Biomarker Linked to Cortical Excitability and p-tau181

Can EEG Reveal Clues to Alzheimer’s Risk?

Could brainwaves help researchers better understand the earliest changes linked to Alzheimer’s disease? A recent study suggests they might. Researchers from the Barcelona Brain Health Initiative explored whether cortical excitability—how responsive the brain is—might serve as an Alzheimer’s EEG biomarker, especially when combined with blood-based markers like p-tau181. Using our Enobio EEG system, the team studied healthy adults aged 40–65 and uncovered intriguing age-dependent patterns in brain function.

While it’s too early to call EEG used alone as a predictive test for Alzheimer’s, this research offers intriguing early evidence that brain activity patterns could be associated with subtle changes well before memory problems appear.

Measuring cortical excitability with EEG and TMS

The team used two approaches to assess cortical excitability: spontaneous activity measured by EEG, and brain responses triggered by TMS-EEG. Our Enobio system was used to record resting-state EEG in 648 healthy adults, aged 40 to 65, allowing researchers to study subtle brain dynamics in a real-world, non-invasive setting.

These recordings helped quantify the brain’s excitation/inhibition balance, thought to play a role in early neurodegenerative processes, though this is still a topic of active investigation.

Spontaneous EEG shows age-related patterns

Interestingly, the study found that spontaneous EEG signals, particularly a measure related to aperiodic activity, were associated with p-tau181 levels in participants aged 54 and above. This suggests that changes in brain function may begin to appear subtly in late middle age, even in healthy individuals.

Although this points to a potential Alzheimer’s EEG biomarker, the authors stress that this is a correlation, not a confirmation of causality.

TMS-EEG Identifies Localized Alzheimer’s EEG Biomarker

A subset of 47 participants also underwent TMS-EEG, where brief magnetic pulses stimulated the brain while EEG tracked the response. These evoked responses offered a more targeted look at cortical excitability.

Among older participants, this perturbation-based excitability was also linked to p-tau181, suggesting this may be a sensitive method for detecting brain function changes.

What's the value of portable EEG in large-scale research?

One standout aspect of this study is the scale and accessibility of data collection. Our Enobio EEG system enabled researchers to collect high-quality brain activity data from hundreds of participants outside traditional lab settings.

This kind of setup makes population-level neuroscience more feasible and opens the door to studying subtle brain changes in real-world environments—a crucial step for moving from research to public health applications.

What does this mean for the future of Alzheimer’s detection?

This study shows how non-invasive methods could play a part in future multi-modal risk assessment strategies. The hope is that, by combining blood biomarkers like p-tau181 with brain activity data, clinicians might one day be able to identify early physiological shifts in people long before symptoms arise.

Whether interventions targeting cortical excitability, such as neuromodulation or lifestyle changes, can modify these trajectories remains an open and exciting area of study.

Conclusion: Charting a New Path for Alzheimer’s EEG Biomarkers

This study adds to growing evidence that EEG could help track early brain changes linked to Alzheimer’s. While the Alzheimer’s EEG biomarker identified here is not yet ready for clinical use, it lays important groundwork for combining EEG with blood biomarkers like p-tau181 to identify at-risk individuals before cognitive symptoms develop.

Still, the findings are early, and more work is needed to clarify how EEG and blood markers like p-tau181 interact over time. At Neuroelectrics, we’re excited to support research that pushes the boundaries of brain science, and we’ll keep working to provide tools that make this kind of innovative study possible.

Discover the features of our Enobio EEG system and how it's used in research.

References:

• Perellón-Alfonso, Ruben et al. Spontaneous and perturbation-based EEG cortical excitability markers are associated with plasma p-tau181 concentration in healthy middle-aged adults. Heliyon, Volume 10, Issue 24, e41118. Published online December 9, 2024. doi:10.1016/j.heliyon.2024.e41118

• Barcelona Brain Health Initiative