# Alzheimer's Disease Diagnosis Shifts Global Health Landscape

> New blood tests and drugs target Alzheimer's disease before symptoms appear.
- Title: Alzheimer's Disease Diagnosis Shifts Global Health Landscape
- Summary: New blood tests and drugs target Alzheimer's disease before symptoms appear. Alzheimer's disease is now defined by biomarkers like amyloid plaques, affecting…
- Keywords: alzheimer's, amyloid, biomarkers, lecanemab, donanemab, blood tests, preclinical, fda, medicare, apoe4, tau, neurodegeneration
- Source: The New Yorker — https://newyorker.com/magazine/2026/11/09/did-the-world-just-gain-hundreds-of-millions-of-alzheimers-patients
- Author: Manvir Singh
- Published: 2026-11-02T11:00:00+00:00
- Read time: 2 min
- Topics: alzheimer's, amyloid, biomarkers, lecanemab, donanemab, blood tests, preclinical, fda, medicare, apoe4, tau, neurodegeneration
## Alzheimer's Conference Optimism
Ten thousand people attended London's Alzheimer's Association conference this July, with virtual participants joining.

> We estimate a man by how much he remembers
## Decades of Research Disappointment
The U.S. spent twenty billion dollars on Alzheimer's research from 1974 to 2.020 without approving a single treatment.
## Current Alzheimer's Impact
Alzheimer's affects one in nine Americans over sixty-five and costs the economy three-quarters of a trillion dollars annually.
## Alzheimer's Disease Definition Shift
Alzheimer's disease is now defined by biomarkers like amyloid plaques, not just cognitive decline.
## Amyloid as Key Biomarker
Blood tests developed over five years now measure amyloid levels as accurately as PET scans.
## FDA Approves New Drugs
The FDA approved three antibody treatments since 2021 to slow Alzheimer's progression.
## Kewman's Genetic Risk
Kewman, a seventy-six-year-old retired psychologist, carries two copies of the APOE 4 gene, increasing Alzheimer's risk.
## Preclinical Diagnosis
Cognitively normal people with amyloid plaques are now classified as having preclinical Alzheimer's disease.
## Amyloid-Targeting Drugs
Lecanemab and donanemab are FDA-approved drugs that target amyloid plaques to slow cognitive decline.
## Kewman's Treatment Trial
Kewman participated in a trial testing lecanemab, receiving monthly infusions for four years with no cognitive decline.
## Treatment Effectiveness Debate
Cochrane review found amyloid-targeting drugs show little to no difference in cognitive decline, despite reducing amyloid plaques.
## Alzheimer's Association Stance
The Alzheimer's Association argues biomarkers should define Alzheimer's disease to enable early treatment.
## Clinical Trial Challenges
Early trials of amyloid-targeting drugs showed mixed results, with some patients experiencing brain swelling or microbleeds.
## Amyloid's Role in Disease
Amyloid plaques and tau tangles are now considered key biomarkers for Alzheimer's disease, even before symptoms appear.
## Kewman's Experience
Kewman, with high genetic risk, remains cognitively normal despite having amyloid plaques.
## Future Treatment Outlook
Early treatment of amyloid buildup may prevent Alzheimer's dementia, but current drugs show modest benefits.
## Key takeaway

Alzheimer's disease is now defined by biomarkers like amyloid plaques, affecting hundreds of millions globally with potential early treatments.