New diagnostic criteria for Alzheimer disease (AD)—jointly issued by the National Institute of Aging and the Alzheimer’s Association in 2011—update the guidelines that had been widely used for the last 30 years.
Here, in the first of his 2 podcasts (for Part 2, please click here), Christopher van Dyck, MD, discusses these key advances in the new guidelines:
• The new criteria formalize different stages of AD disease
• The new criteria incorporate biomarkers of the underlying disease process
For the past 30 years, AD has been diagnosed and treated as a single stage disease (ie, dementia). In the new criteria, dementia is considered end stage disease. The focus has shifted to earlier diagnosis of AD; in the near future, the focus is expected to be on treatment at an earlier stage.
Over last several years, a number of biomarkers in AD have been studied. These fall into 2 categories:
• Amyloid deposition (reduction in soluble amyloid; increase in amyloid deposition)
• Neuronal injury (increase in Tao protein; evidence of brain atrophy on MRI scan; evidence of metabolic reduction on PET scan)
Dr van Dyck also discusses:
• Abeta42, a cerebral spinal fluid “signature” that appears to predict progression to AD
• Amyloid PET imaging just approved in April 2012 to detect amyloid plaque in the brain
The new guidelines consist of 2 key advances:
(1) Formalized stages of AD now assist clinicians in making earlier diagnoses. These consist of the preclinical or presymptomatic stage; the mild cognitive impairment (MCI) stage; and the dementia stage
(2) Biomarkers for amyloid pathogenesis and neuronal injury can now be clinically identified to detect the underlying disease process
Dr van Dyck is Professor of Psychiatry at Yale School of Medicine and Director of the Alzheimer’s Disease Research Unit at Yale in New Haven, Connecticut.