December 11, 2012
Combining Diagnostic Tests Improves Alzheimer’s Prediction
Lee Rannals for redOrbit.com — Your Universe Online
More than 35 million people around the world are living with Alzheimer's disease, according to the World Health Organization. This disease is incurable and the prevalence is expected to double by 2030.
"Although there is no cure for Alzheimer's disease, there are four symptomatic treatments that might provide some benefits," coauthor P. Murali Doraiswamy, M.D. and professor of psychiatry at Duke University Medical Center, said in a statement. "So developing the right combination of diagnostic tests is critical to make sure we enable an accurate and early diagnosis in patients, so they can evaluate their care options."
The team combined diagnostic tests, including imaging and cerebrospinal fluid biomarkers, and found by doing so, it can improve prediction of conversion from mild cognitive impairment (MCI) to Alzheimer's disease.
The study looked at 97 patients with MCI from the Alzheimer's Disease Neuroimaging Initiative. They analyzed baseline MRI and FDG-PET results, as well as cerebrospinal fluid proteins and compared these to cognitive outcomes at two to three years.
Findings from the study showed combining MRI, FDG-PET and cerebrospinal fluid data with routine clinical tests significantly improved the accuracy of predicting conversion to Alzheimer's disease. The combined testing reduced false classification rate from 41.3 percent to 28.4 percent.
"In an ideal world, you'd obtain all information available–regardless of cost or number of tests–for the best prediction of cognitive decline," Jeffrey R. Petrella, M.D., associate professor of radiology at DUMC, said in a statement. "However, there's a trade-off between adding testing–some of which may add little new information–with the inconvenience, cost and risk to the patient."
FDG-PET contributed more information to routine tests than cerebrospinal fluid or MRI.
"Though all the tests added some unique information," Dr. Petrella said. "FDG-PET appeared to strike the best balance, adding the most prognostic information for patients with mild cognitive impairment."
The researchers say additional long-term studies are still needed in order to further validate the data.
"Because new treatments are likely to be most effective at the earliest stages of Alzheimer's disease, there is great urgency to develop sensitive markers that facilitate detection and monitoring of early brain changes in individuals at risk," Petrella added.