A new Mayo Clinic study suggests new methods to improve identification of individuals in the early stages of Alzheimer’s disease.

As technology and scientific methods have improved, detection of the disease before an individual shows outward signs of cognitive problems has become important.

The task of determining early-onset Alzheimer’s is challenging for physicians and researchers, in part, because they have not been using common and specific terms to describe the disease’s initial phases.

The new study recommends adding categories to more effectively identify and treat people and give researchers standard definitions to work with.

Mayo researchers assessed new guidelines for preclinical Alzheimer’s disease (AD) that were recently published by a working group formed by the National Institute on Aging and the Alzheimer’s Association (NIA-AA).

The group’s work marked the first attempt to define criteria for Alzheimer’s preclinical phase — the long time period in which Alzheimer’s pathology and biomarkers of that pathology become abnormal, while subjects remain clinically asymptomatic.

The guidelines represented a significant step forward because evidence increasingly suggests this early phase is the best time to treat the disease.

The Mayo researchers concluded, however, that the three stages defined by the workgroup are not sufficient to describe all cognitively normal elderly patients. They recommend adding two more groups.

“The important guidelines developed by the NIA-AA workgroup were a vital step in clarifying the progression of this devastating disease and aiding in earlier diagnosis,” says lead author Clifford R. Jack, Jr., M.D., a Mayo Clinic neurologist.

“Our study builds on that work by recommending two additional sub-groups that merit attention.”

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.

“Without the additional categories we recommend, more than half of all preclinical AD patients would be ‘forced’ into a category that was not descriptive of their current state,” says co-author Ronald C. Petersen, M.D., Ph.D.

“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.”

The study is published in this month’s issue of the Annals of Neurology.

Source: Mayo Clinic