At Risk for Alzheimer's? New ID Method May Tell
Researchers at University of California, Davis, report on a possible new way to identify a healthy person’s risk of Alzheimer’s disease. The new ID method involves abnormal brain images along with certain biomarkers in the cerebrospinal fluid.
Early detection of Alzheimer’s disease has remained elusive, although not for a lack of research into various approaches. In 2009, for example, scientists at the US Department of Energy’s Brookhaven National Laboratory developed an x-ray technique they hope will help track the amyloid beta plaques that form in the brains of Alzheimer’s patients. In June 2010, scientists at Cedars-Sinai Medical Center reported they were experimenting with an eye exam technique that, for now, detects plaque in the retinas of mice, the same plaque that forms in the brain of Alzheimer’s patients.
The new approach was discovered when Laurel Beckett, a professor of public health sciences at UC Davis and the study’s lead author, along with her team, evaluated data from the Alzheimer’s Disease Neuroimaging Initiative. This provided them access to brain scans, clinical data, and other laboratory results from spinal fluid and blood tests from more than 800 older adults.
The 800 adults represented a wide spectrum of cognitive abilities, ranging from those who had no problems to some with mild cognitive impairment, to others who had mild or moderate Alzheimer’s disease. Becket’s team evaluated data from 220 normal older adults who had had magnetic resonance imaging (MRI) and clinical examinations. About 50 percent of them also had spinal fluid samples.
Among the 96 participants, analysis identified three subgroups of individuals based on their imaging and laboratory results. Over the next three years, few of these healthy individuals demonstrated any cognitive changes. In one subgroup, however, which made up about 10 percent of the sample, the individuals declined at nearly five times the rate as healthy older adults. This group of individuals also had the most extreme MRI and spinal fluid measurement results, which lead the authors to suggest that these findings indicate the earliest stages of subclinical cognitive decline.
Beckett noted that currently, “by the time people get diagnosed with Alzheimer’s using cognitive tests, there’s already a lot of brain damage.” She and her team hope that “in the future methods that combine brain imaging and biomarker assessments can push the diagnosis back.” The new ID method for Alzheimer’s “could improve clinical trials for prevention and reduce the numbers of study participants necessary to speed drug discovery” as well.
UC Davis news release, July 9, 2010