The Alzheimer's Diagnosis Gap: 75% Undiagnosed — Could EEG Close It?
Every September, Alzheimer's Disease International (ADI) and dementia organizations worldwide mark World Alzheimer's Month with a campaign built around a single idea. This year's theme puts it plainly: "The Earlier You Know, The More You Can Do — A Dementia Diagnosis Matters."
It's a simple statement, but it pushes back against something a lot of people still believe: that getting an Alzheimer's diagnosis isn't worth pursuing, because nothing can be done anyway.
Why Does an Alzheimer's Diagnosis Matter?
An Alzheimer's diagnosis isn't an endpoint — it's what ADI calls "the key to unlocking a whole raft of treatment, care and support options." A confirmed diagnosis opens the door to cognitive and lifestyle interventions, clinical trial eligibility, care planning, legal and financial planning, and support for caregivers. None of that can happen if the diagnosis never comes.
The Global Alzheimer's Diagnosis Gap, By the Numbers
According to ADI's World Alzheimer Report, an estimated 75% of people living with dementia worldwide have never received a formal diagnosis. In lower- and middle-income countries, that figure climbs to as high as 90%. Even in wealthier countries, actual diagnosis rates can be as low as one in four.
That gap isn't only about hospital access. The same report found that roughly one in three clinicians surveyed believed a dementia diagnosis wasn't worth pursuing, because they didn't think anything could be done about it. If that belief exists among healthcare professionals, it's easy to see why so many individuals and families quietly decide not to ask the question at all — and why closing the Alzheimer's diagnosis gap is as much about stigma as it is about access.
Why Is Alzheimer's Diagnosis So Hard to Get?
Part of the reason so many cases go undetected is practical. The tools that reliably confirm what's happening in the brain — PET scans, MRI, spinal fluid tests — are also the hardest to access: expensive, invasive, and unevenly available even in well-resourced health systems. A primary care visit, let alone a community clinic in a lower-resource region, rarely has any of these as a first-line option.
This is where a quieter shift in Alzheimer's research over the past few years matters. Alongside blood-based markers, researchers have been asking a more basic question: can something meaningful about Alzheimer's risk be learned from a signal that's already cheap, portable, and non-invasive — brain electrical activity itself?
How EEG Research Could Make Alzheimer's Diagnosis Earlier and More Accessible
Over the past year, our team has published two pieces of research that speak directly to this question.
Working with the Barcelona Brain Health Initiative, researchers used a portable, wireless EEG system to record brain activity in 648 healthy adults between the ages of 40 and 65 — people with no dementia diagnosis and, in most cases, no obvious symptoms. As we covered in "Alzheimer's EEG Biomarker Linked to Cortical Excitability and p-tau181," patterns in that everyday EEG signal were associated with p-tau181, a blood-based marker already linked to Alzheimer's pathology. In other words, signals potentially related to Alzheimer's risk may be visible in ordinary brainwave recordings of ordinary middle-aged adults, well before any clinical symptoms would prompt someone to seek an Alzheimer's diagnosis in the first place.
A companion piece of research helped explain why those EEG changes show up at all. As we explained in "Modeling Alzheimer's in the Brain: How Neural Mass Models Reproduce EEG Biomarkers," a computational model of brain tissue showed how two different aspects of Alzheimer's pathology — amyloid-beta and tau — leave distinct fingerprints on brainwave patterns as the disease progresses: an early phase where certain brain rhythms actually intensify, followed by a later phase where they fade. That pattern, once purely theoretical, now lines up with what's observed in real EEG recordings, giving researchers a clearer mechanistic reason to trust EEG as a window into what's happening at the cellular level.
What This Means If You're Concerned About Memory Changes
Far from being standard tests available in a routine clinical visit, these diagnostics are barely accessible and restricted to top medical centers in the most developed nations. But it points toward a future where an Alzheimer's diagnosis doesn't have to start with an expensive scan or an invasive procedure. Until that future arrives, the guidance from ADI and the Alzheimer's Association stands: if you or someone you love is showing signs of memory or cognitive change, don't let the assumption that "nothing can be done" stand in the way of asking a doctor. An Alzheimer's diagnosis — even an early one — is what makes the "more you can do" part possible.
For Researchers and Clinicians: Bring EEG-Based Insight to Your Alzheimer's Work
The recordings behind this research weren't made with rare, one-off lab equipment. They were collected with Enobio, our wireless, medical-grade EEG system — the same platform available today to teams researching cognitive decline and early biomarkers, and, in its clinically-certified form, Enobio Dx (CE-marked and FDA-cleared), to hospitals and memory clinics building EEG into their own patient-monitoring workflows.
If your team is working on early detection, biomarker validation, or longitudinal cognitive monitoring — in Alzheimer's or any other neurological condition — we'd like to show you what the platform can do. Get more information.
References
Alzheimer's Disease International. "World Alzheimer's Month 2026 Campaign Toolkit."
Alzheimer's Disease International. "Over 41 Million Cases of Dementia Go Undiagnosed Across the Globe — World Alzheimer Report Reveals" (World Alzheimer Report 2021).
Alzheimer's Association. "World Alzheimer's Day."
Neuroelectrics Blog. "Alzheimer's EEG Biomarker Linked to Cortical Excitability and p-tau181."
"Spontaneous and Perturbation-Based EEG Cortical Excitability Markers Are Associated with Plasma p-Tau181 Concentration in Healthy Middle-Aged Adults." ScienceDirect.
Neuroelectrics Blog. "Modeling Alzheimer's in the Brain: How Neural Mass Models Reproduce EEG Biomarkers."
"Fast Interneuron Dysfunction in Laminar Neural Mass Model Reproduces Alzheimer's Oscillatory Biomarkers." Human Brain Mapping. DOI: 10.1002/hbm.70428
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