Early Stages of Alzheimer's Categorized

Alzheimers disease categorized by Mayo Clinic

(RxWiki News) Acknowledging that early stage Alzheimer's disease patients often do not yet have symptoms, Mayo Clinic researchers have proposed adding two pre-clinical stages to better classify patients.

Such a change could help ensure that those in the early phases of the disease receive treatment sooner since evidence suggests this is the best time to treat the disease.

"Make an appointment with a neurologist if you suspect Alzheimer's."

Dr. Ronald C. Petersen, co-author of the research, a neurologist and the Cora Kanow Professor of Alzheimer's Disease Research at Mayo Clinic, said that without the addition of the two categories, more than half of pre-clinical Alzheimer's patients would be forced into a category that does not accurately describe their state.

More clearly defining the pre-clinical stages of Alzheimer's disease and the categories of elderly patients who should not be classified as having pre-clinical Alzheimer's can aid doctors in improving diagnosis and management of the disease, he said.

Researchers assessed new guidelines for pre-clinical Alzheimer's disease that were recently published by a working group formed by the National Institute on Aging and the Alzheimer's Association. This marks the first time the group had worked to define criteria for the pre-clinical phases of Alzheimer's.

The pre-clinical phase includes periods when patients may have no outward signs of the disease, but Alzheimer's pathology and biomarkers may be abnormal.

Mayo Clinic researchers found the three existing stages identified simply as stages 1, 2 and 3, insufficient.  They recommend adding Stage 0 for patients with normal biomarkers and no evidence of cognitive impairment, of which about 43 percent of elderly individuals would fall.

They also proposed adding a category called SNAP, which stands for Suspected Non-Alzheimer's disease Pathophysiology. This group of patients have normal brain amyloid imaging, but abnormal neurodegeneration markers. About 23 percent of elderly patients would fall into this category.

"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," said Dr. Clifford R. Jack, lead author, a Mayo Clinic neurologist and the Alexander Family Professor of Alzheimer's Disease Research.

The guideline recommendation is published in this month's issue of the Annals of Neurology.

Review Date: 
October 17, 2011