Spinal Fluid May Help Diagnose Alzheimer's disease

Searching for a better screen for early Alzheimer's disease, researchers think they have found a marker of change in the brain that precedes the onset of the disease by five to 10 years.

The indicator of trouble to come, they say, is a shift in the levels of specific components of the cerebrospinal fluid (CSF) in the brain and spinal cord. Among patients already diagnosed with mild cognitive impairment, a drop in such levels appears to be a sign of Alzheimer's years before symptoms develop.

The discovery, published in the January issue of Archives of General Psychiatry, could potentially aid in the use of disease-modifying therapies, which are designed to work best if applied when a patient is still in the early stages of disease.

"These markers can identify individuals at high risk for future [Alzheimer's disease] at least five to 10 years before conversion to dementia," study author Dr. Peder Buchhave, of Lund University and Skane University in Sweden, noted in a journal news release. "Hopefully, new therapies that can retard or even halt progression of the disease will soon be available. Together with an early and accurate diagnosis, such therapies could be initiated before neuronal degeneration is too widespread and patients are already demented."

The study results stem from more than nine years of follow-up to prior research that had involved 137 patients diagnosed with mild cognitive impairment, a mental state that often precedes dementia.

Over the course of the study, nearly 54 percent of the patients went on to develop Alzheimer's, while another 16 percent were ultimately diagnosed with different forms of dementia.

Specifically, among those who developed Alzheimer's, the researchers found that key aspects of their cerebrospinal fluid dropped off in the years before. In addition, other fluid properties actually went up.

The study team said that they believe that about nine out of every 10 patients with mild cognitive impairment who experience such fluid shifts will eventually go on to develop Alzheimer's disease.

Commenting on the study, one expert in the United States said that the new research "provides confirmation of the general concept that CSF can predict the progression of mild memory loss to mild dementia."

Dr. Sam Gandy, associate director of the Mount Sinai Alzheimer's Disease Research Center at Mount Sinai School of Medicine in New York City, added that the results of the European study largely echo those of a trial reported by researchers at the U.S. National Institutes of Health in 2010.

He noted that methods of early detection might prove valuable for research into the treatment of Alzheimer's disease.

"Most new Alzheimer's drugs are aimed at reducing amyloid [protein plaque] accumulation, and the general consensus is that these drugs will only work at early or presymptomatic stages of disease," said Gandy, who is also Mount Sinai Chair in Alzheimer's Disease Research. "The new paper strengthens the likelihood that CSF biomarkers can be useful for identifying that population of subjects with early or presymptomatic disease in order to recruit them into trials."

For more on early signs of Alzheimer's, visit the Alzheimer's Association.