Researchers in Belgium have found another potential biomarker for detecting Alzheimer's. Using a spinal tap test, a team at Ghent University took samples of cerebrospinal fluid from 400 elderly individuals in varying states of dementia, and of the 102 participants considered to have Alzheimer's, 90 had an identical biomarker.
The test, whose results are published in August's Archives of Neurology, measured concentrations of three different biomarkers, amyloid-beta, tau and phospho-tau. Nearly one third of those without any cognitive issues had the same biosignature, raising questions about the test's efficacy. It's unclear if that third, or the three-quarters of mildly memory impaired participants, affected will develop Alzheimer's. "These may be people who are able to tolerate a high burden of these toxic (proteins) without developing symptoms," neurologist John Growdon of Massachusetts General Hospital tells WebMD.
Currently, Alzheimer's is only truly diagnosed through an autopsy. And in autopsies conducted of study participants, 64 of 68 Alzheimer's confiming autopsies carried one of the three biomarkers. But Growdon tells WebMD he doubts the spinal tap procedure will be available to many in the near future. "It would take a sea change where group practices and hospitals develop lumbar puncture centers like the centers that now provide colonoscopies or brain scans," he says.
Still, Growdon and his colleague Zara Herskovits of the Brigham & Women's Hospital in Boston touted the results as "ample evidence" of the test's value in an editorial. They believe these biomarkers show up 10 or more years before the visible onset of dementia symptoms.