Measuring certain proteins in spinal fluid can accurately diagnose Alzheimer's and predict which patients with memory problems will develop the fatal brain-wasting disease, Belgian researchers said Monday. And they may also help identify early signs of the disease in healthy people, the team reported in the Archives of Neurology. “The unexpected presence of the Alzheimer's disease signature in more than one-third of cognitively normal subjects suggests that Alzheimer's disease pathology is active and detectable earlier than has heretofore been envisioned,” Geert De Meyer of Ghent University in Belgium and colleagues wrote. They said measuring traces of beta amyloid and tau - two proteins associated with the telltale plaques and tangles that form in the brains of patients with Alzheimer's - accurately detected Alzheimer's in 90 percent of patients with the disease. They were also able to detect 100 percent of people with memory impairments who would progress to Alzheimer's disease within five years. And they detected Alzheimer's proteins in 36 percent of people with normal brain function. The study is the latest to show that measuring disease-related proteins in spinal fluid is useful in diagnosing Alzheimer's disease. Currently, only an autopsy can confirm that a person has Alzheimer's, a fatal and incurable deterioration of the brain that affects more than 26 million people globally. Doctors diagnose Alzheimer's by excluding other causes of memory loss, such as stroke, tumors and heavy drinking. They can also administer simple paper-and-pencil tests. But biomarkers - proteins and imaging techniques - are helping to identify the disease much earlier. The new result is one of a number of remarkable recent findings about Alzheimer's. After decades when nothing much seemed to be happening, when this progressive brain disease seemed untreatable and when its diagnosis could be confirmed only at autopsy, the field has suddenly woken up. Alzheimer's, medical experts now agree, starts a decade or more before people have symptoms. And by the time there are symptoms, it may be too late to save the brain. So the hope is to find good ways to identify people who are getting the disease, and use those people as subjects in studies to see how long it takes for symptoms to occur and in studies of drugs that may slow or stop the disease. Researchers are finding simple and accurate ways to detect Alzheimer's long before there are definite symptoms. In addition to spinal fluid tests they also have new PET scans of the brain that show the telltale amyloid plaques that are a unique feature of the disease. And they are testing hundreds of new drugs that, they hope, might change the course of the relentless brain cell death that robs people of their memories and abilities to think and reason. A lot of work lies ahead, researchers say — making sure the tests are reliable if they are used in doctors' offices, making sure the research findings hold up in real-life situations, getting doctors and patients comfortable with the notion of spinal taps, the method used to get spinal fluid. But they see a bright future. One drawback, though, is that spinal fluid is obtained with a spinal tap, and that procedure, with its reputation for pain and headaches, makes most doctors and many patients nervous. The procedure involves putting a needle in the spinal space and withdrawing a small amount of fluid. Doctors say, however, that spinal taps are safe and not particularly painful for most people, but there needs to be an education campaign to make people feel more comfortable about having them.
