Today, Prof. Howard Feldman presented revised diagnostic criteria for Alzheimer’s disease on behalf of the International Working Group (IWG) at the Clinical Trials on Alzheimer’s Disease (CTAD) conference in Madrid.
The IWG, led by Professor Bruno Dubois and Dr. Nicolas Villain (Hôpitaluniversiteit Pitié-Salpêtrière-Sorbonne Université, Paris, France), Professor Howard Feldman (University of California, San Diego, USA) and Professor Giovanni Frisoni (Hôpitauxuniversiteits de Genève, Geneva, Switzerland) and consisting of 46 international experts from 17 countries, including a representative of Alzheimer Europe, reviewed the available evidence on the role and influence of biomarkers on the diagnosis and definition of Alzheimer’s disease.
The IWG has proposed a number of important recommendations that were published in today’s newspaper in parallel with this presentation Journal of the American Medical Association – Neurology (JAMA Neurology):
- Alzheimer’s disease should be defined as a clinical-biological entity where the diagnosis is made considering both a clinical condition and the support of positive amyloid and tau biomarkers.
- This definition supports a diagnosis of Alzheimer’s disease at an early prodromal stage once mild but distinct clinical features are present.
- For people who are cognitively normal and have only positive amyloid-related biomarkers, the IWG proposes the term “Asymptomatic at risk of Alzheimer’s disease” as these individuals have an increased risk of developing symptomatic Alzheimer’s disease throughout their lives .
- The IWG also proposes the category of ‘presymptomatic Alzheimer’s disease’ for people with autosomal dominant genetic mutations, with Down syndrome and with other specific biomarker profiles that place them at extremely high risk of expressing the clinical disorder (e.g. combining of amyloid positivity with tau accumulations in the neocortical areas).
Presenting these recommendations, Professor Feldman emphasized: “The IWG recommendations published today advocate the diagnosis of Alzheimer’s disease as one that is clinically established with the support of biomarkers that reflect the pathology of the disease. We believe that these biomarkers in themselves reflect the different levels of risk of developing disease in people without clinical symptoms.”
In its recommendations, the IWG also takes a position on the Alzheimer’s Association Workgroup’s recently published “Revised Criteria for Diagnosis and Staging of Alzheimer’s Disease.” The IWG emphasizes that a purely biological definition of Alzheimer’s disease, which extends the diagnosis of Alzheimer’s disease to cognitively normal people with one core biomarker, could lead to false positives and people potentially living with the label of Alzheimer’s disease without ever developing symptoms (patients -pending) with major social consequences. Dr. Nicolas Villain commented: “As our understanding of Alzheimer’s disease evolves, advances in biomarkers allow earlier diagnosis, even before symptoms appear. However, it is crucial to emphasize that our main focus should be on the potential future risks of cognitive decline associated with it. with these biomarkers, rather than just with the biological changes themselves.”
These recommendations are the result of a joint effort by 46 international experts who emphasize that the diagnosis of Alzheimer’s disease should rely primarily on clinical evaluation, supported by biomarkers. Importantly, we distinguish between two groups: those who show typical Alzheimer’s symptoms and have positive biomarkers are diagnosed with the disease, while those who have positive biomarkers but do not have typical Alzheimer’s symptoms are considered at risk. This distinction is crucial as it paves the way for more targeted research, risk assessment and the development of personalized treatments for people at risk.”
Professor Bruno Dubois
The IWG also emphasized the importance of continued research in asymptomatic people at risk for AD to better understand and measure individual risk. Professor Frisoni commented: “Further developing brain health services for dementia prevention could lead to better risk assessment, risk communication and risk reduction strategies that target modifiable risk factors.”
Jean Georges, Executive Director of Alzheimer Europe and one of the co-authors welcomed the recommendations: “The IWG recommendations are in line with Alzheimer Europe’s current position against routine testing of biomarkers for diagnostic purposes in individuals without any cognitive symptoms. positive for amyloid because having preclinical Alzheimer’s disease can have significant negative psychological consequences. Instead, we recommend disclosing an individual’s risk, and ensuring that appropriate support, advice and tailored risk reduction plans are provided to help them process and manage this information.