53% of Alzheimer's cases in Europe go undetected, experts call for systemic change

For the first time, medicine can slow Alzheimer's disease. However, the new drugs only work in the early stages, and across Europe, most people are still diagnosed too late — or not at all.

Mercè Boada Rovira, one of Spain's most experienced dementia clinicians, told a policy meeting in Rome what it would take to change that.

A Call for Systemic Change

Boada has spent three decades diagnosing dementia at the ACE Alzheimer Centre in Barcelona. She was speaking at MindShift, a policy dialogue held in Rome on 9–10 June, which brought together clinicians, policymakers, and patient representatives from 12 European countries. The meeting was convened to align national strategies and shape a common European approach to Alzheimer's care.

Her message on early diagnosis was clear: the science to catch Alzheimer's early exists, but the systems to deliver it do not — and too many patients are never found.

"The 53% is undetected," she said.

That figure, she argued, is not only "a clinical opportunity" but "a government health system responsibility."

How the Diagnosis Is Made

Diagnosing Alzheimer's is slow, skilled work. A full neuropsychological assessment takes more than 45 minutes, Boada said, and adding tests of functional and executive ability pushes it past an hour.

For most of the past three decades, clinicians relied on a symptom-based "phenotype" diagnosis — and there was little to offer even a confirmed patient. The diagnosis shaped how someone was cared for, not whether the disease could be slowed.

The change came, she said, when clinicians added biomarkers to that phenotype:

"We include biomarkers and change the treatment."

She called this "the novelty during the last twenty years."

The right response also shifts with the stage, she noted: someone with mild cognitive impairment and someone with moderate Alzheimer's need different priorities, not the same package of care.

Catching It Before the Symptoms

That biological turn is what makes earlier detection possible — and blood-based tests have moved it from research into the clinic.

"A blood test for Alzheimer's disease is no longer an abstract concept," said Angela Bradshaw, research director at Alzheimer Europe. "It's a clinical reality."

The biology runs years ahead of the symptoms:

• Amyloid buildup shows up on PET scans 10 to 20 years before cognitive decline.
• According to research published in Nature Communications, newer blood markers such as p-tau217 can flag the earliest changes, even before a PET scan becomes positive.

For patients, the stakes of reaching that window are now concrete: the new anti-amyloid drugs are licensed only for early Alzheimer's. A diagnosis that comes too late decides not just how the disease is managed, but whether it can be treated at all.

The Tools Still Need Standardising

The promise comes with a caveat. Michael Schöll, a molecular-medicine professor at the University of Gothenburg, told the meeting that blood tests can today "clearly support a clinical diagnosis within the symptomatic stage," but in the earliest stages, their predictive value is limited to ruling the disease out.

"I would not go to someone who doesn't have symptoms and diagnose Alzheimer's disease based on a blood-based biomarker alone," he said.

Turning a test into a reliable tool everywhere is a further hurdle. Umberto Basile, a member of the Italian Society of Clinical Biochemistry and Clinical Molecular Biology – Laboratory Medicine (SIBioC), called blood-based medicine "the Cinderella of medicine" — even though laboratory assays underpin most diagnoses. Scaling the new markers, he said, would demand:

• Standardised sampling
• Harmonised assays
• Common cut-off values across laboratories and manufacturers

Building the Reserve

Detection is only half of Boada's argument. The other half is what can be done before the pathology takes hold. The brain, she said, keeps growing "with curiosity, learning and intellectual engagement even in old age," and cognitive reserve belongs in the toolkit alongside biomarkers and drugs.

She reached for Rita Levi-Montalcini, the Nobel laureate who worked into old age: the brain, in her phrase, "does not retire."

The Problem Is the System

The problem, in Boada's view, is not the science — but the system.

More than half of cases go undetected, she said, and closing that gap is a matter of public-health design, not clinical goodwill. The scale is not disputed: Alzheimer Europe estimates more than half of dementia cases in Europe are never formally diagnosed, with an average wait of three to three and a half years.

"Biological diagnosis requires system transformations," she said.

Those transformations cost money. Without a budget, she warned, it is "impossible to transform the public health system."

"I need money here."

She also pressed a point about who holds the system up. Care still falls disproportionately on women — daughters and daughters-in-law — and on migrant workers. "Without" them, she implied, the system would not function.