Biomarkers May Help Measure Rate of Decline in Dementia

TUESDAY, May 12, 2009 (HealthDay News) -- Checking levels of certain biomarkers in cerebrospinal fluid may help predict the rate of cognitive decline in people with very mild dementia, and this information could be used to improve the effectiveness of clinical trials, say U.S. researchers.

Their study, published in the May issue of the journal Archives of Neurology, included 49 people who'd been diagnosed with very mild Alzheimer's disease. Samples of cerebrospinal fluid taken from the patients were tested for several biomarkers associated with Alzheimer's, including alpha-beta peptide 1-42 (Aβ42), tau, and phosphorylated tau 181 (ptau 181).

The patients had at least one follow-up assessment an average of 3.5 years later and the researchers found that the "rate of dementia progression was significantly more rapid in individuals with lower baseline cerebrospinal fluid Aβ42 levels, higher tau or ptau 181 levels or high tau:Aβ42 ratios."

Finding effective treatments for Alzheimer's will likely depend on early identification of patients, noted study author Dr. Barbara J. Snider and colleagues at Washington University School of Medicine in St. Louis.

"Because there is a growing emphasis on enrolling individuals with less cognitive impairment into clinical trials of [possible] anti-Alzheimer's disease agents, methods are needed that will identify individuals with very mild dementia of the Alzheimer's type who are more likely to exhibit measurable cognitive decline during the study," the researchers wrote.

"Although the number of participants in this study was relatively small, the results suggest that cerebrospinal fluid biomarkers might be useful as entry criteria for clinical trials of disease-modifying therapies for mild cognitive impairment and very mild dementia of the Alzheimer type," they noted.

The study findings may "have important implications for reducing the number of participants needed to show an effect in clinical trials for very mild dementia of the Alzheimer type and mild cognitive impairment and, ultimately, to assist in making treatment decisions as more invasive and potentially harmful disease-modifying treatments for Alzheimer's disease become available," the authors concluded.

More information

The U.S. National Institute of Neurological Disorders and Stroke has more about dementia.