Earliest Stages of Alzheimer’s Identified


One American develops Alzheimer’s every 69 seconds. More than 5.4 million Americans have Alzheimer’s disease, and the incidence is only on the rise. Unfortunately, many people are diagnosed too late to receive effective treatment.

Addressing the earliest stages of Alzheimer’s disease, before a patient shows outward signs of cognitive problems, has sometimes been a challenge for physicians and researchers, in part because they have not been using common and specific terms to describe the disease’s initial phases.

A Mayo Clinic study assessed new guidelines for preclinical Alzheimer’s disease that were recently published by the National Institute on Aging and the Alzheimer’s Association (NIA-AA). It is the first attempt to define criteria for preclinical disease while subjects remain clinically asymptomatic.

In addition to stages 1, 2 and 3 identified by the NIA-AA workgroup, the authors suggest two additional categories:

·       Stage 0: Patients with normal biomarkers and no evidence of cognitive impairment. An estimated 43 percent of all cognitively normal elderly people would be classified as Stage 0.

·       SNAP patients: Those with “suspected non-AD pathophysiology.” Such patients have normal brain amyloid imaging studies, but abnormal neurodegeneration biomarkers. An estimated 23 percent of cognitively normal elderly patients would fall into the SNAP category.

Study co-author Ronald C. Petersen, MD, PhD, a neurologist and the Cora Kanow Professor of Alzheimer’s Disease Research at Mayo Clinic says that, “By more clearly defining the stages of preclinical Alzheimer’s disease and categories of elderly subjects who should not be classified as preclinical AD, we can improve its diagnosis and help in the management of this devastating disease.”


For more information on the Mayo Clinic, go to www.mayoclinic.com and www.mayoclinic.org/news.