Combination of Available Tests Helps Predict Alzheimer’s Disease Risk
October 20, 2011
Source:University of California, San Diego School of Medicine
A team of physicians and scientists from several institutions, including the University of California, San Diego School of Medicine (UC San Diego), say that a combination of broadly available medical tests can predict Alzheimer's disease (AD) risk among patients experiencing memory loss.
According to the research, set to be published in the October 25th issue of Neurology, comparing risk factors based on widely available technologies, including magnetic resonance imaging (MRI), cerebrospinal fluid and neuropsychological testing, can help determine which patients are experiencing normal age-related cognitive decline and those at greater risk of dementia that could progress to AD.
“The good news is that we can partially reassure those folks who are negative on these tests, at least regarding their next three years," James Brewer, an associate professor of radiology and neurosciences at UC San Diego, said. "These individuals, despite having a real memory problem, have no greater risk of near-term dementia than a similarly aged healthy person without a memory complaint.”
Challenges of Diagnosis
Mild cognitive impairment is an intermediate stage between the expected cognitive decline of normal aging and the more pronounced decline of dementia. The challenge for doctors has long been to differentiate that risk so they can determine the appropriate course of management.
"Being able to reassure at least some patients that they are not at significant near-term risk of AD is something we never could do in the past," Brewer, who also is part of the Alzheimer's Disease Neuroimaging Initiative research team at UC San Diego, said.
The researchers found that biomarkers from these tests significantly improved accuracy in predicting whether a patient's memory loss could progress to dementia.
Prediction Rate 'Almost Perfect'
When the results of all three tests were combined, the prediction rate was almost perfect, according to the researchers. None of the individuals who tested negative on all three measures went on to develop AD in the three-year follow-up. By comparison, almost 90 percent of individuals who tested positive on all three measures were diagnosed with dementia at the end of three years.
The presence of medial temporal atrophy, determined by automated analysis of MRI using an FDA-approved software package, was associated with the likeliest chance of near-term dementia, with a median dementia-free survival time of only 15 months, according to the report.
“Instead of saying, 'Let's wait a year and see if this gets worse,' our neurologists can say, 'Let's get a volumetric MRI and check back in a month to see if your complaint is due to neurodegeneration.' That ability makes a huge difference in how we proceed," Brewer said.
Adapted from the University of California, San Diego School of Medicine
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