27 Jan 2012

Researchers published new U.S. guidelines for the neuropathologic assessment of Alzheimer’s disease last November—the first revision in 14 years. Prompted by the growing recognition that neuropathological features of AD show up years in advance of clinical symptoms, the new criteria allow pathologists to assess AD pathologic change without a prior diagnosis of dementia. The guidelines— published online November 20, 2011, in Acta Neuropathologica—“amplify methods for evaluating Aβ plaques, better define intermediate levels of AD pathologic change, and emphasize a structured approach to commonly comorbid diseases,” wrote the authors. Thomas Montine of the University of Washington, Seattle, and Brad Hyman of Massachusetts General Hospital, Boston, co-chaired the 16-member committee convened by the National Institute on Aging (NIA) and the Alzheimer’s Association (AA) in 2010 to revise the 1997 NIA-Reagan criteria. Earlier this month, the authors published a second paper, with more detail on theory and discussion behind the new recommendations.

The committee presented drafts of the revamped guidelines last July at the Alzheimer’s Association International Conference (AAIC, formerly ICAD) in Paris, France (see ARF related news story), and in September at a meeting of the Alzheimer’s Disease Research Centers (ADRCs) in San Diego, California. The drafts were revised based on feedback received in response to the draft—mostly “esoteric stuff,” such as what constitutes low versus intermediate burden of lesions, Montine said. “The large picture has not changed.”

Some pathologists noted that they would have preferred that the guidelines define consensus methods for how to work up a case—for example, which brain regions to use or how to prepare samples for staining (see BrainNet Europe Consortium comment). However, Montine said, “We were charged to develop criteria that would be useful to the research community but also to practicing pathologists. Those are two different worlds. We didn’t feel we could prescribe one protocol that would be effective for both groups.” Instead, the two publications offer guidelines for a number of acceptable practices. By the end of the year, the committee hopes to come up with a standard protocol for the 29 AD research centers in the U.S. “That’s different from the original charge,” Montine said, noting they will not specify a protocol for clinicians.—Esther Landhuis