Alzheimer's disease affects about five percent of the 65 to 74 year old population, and almost 50 percent of the 85 and older population, according to the Mayo Clinic. As Alzheimer's disease progresses, the patient loses her ability to take care of herself, as well as important cognitive functions, like memory and judgment. If the disease is identified sooner, treatment can begin that slows down the cognitive decline.
Kaj Blennow and Harald Hampel noted in their Lancet article “CSF markers for incipient Alzheimer's disease” that “the degenerative process in [Alzheimer's disease] probably starts 20 to 30 years before the clinical onset of the disease.” Most of the diagnostic tests for Alzheimer's disease listed by the Mayo Clinic, like neurological testing and brain scans, do not detect the disease until after symptoms start. However, detecting certain biomarkers in the cerebrospinal fluid (CSF) can help indicate Alzheimer's disease earlier.
One biomarker that has been studied in connection to Alzheimer's disease is p-tau 231, or the phosphorylation of tau protein at threonine 231. Katharina Buerger et al. in the Archives of Neurology article “Differential Diagnosis of Alzheimer Disease With Cerebrospinal Fluid Levels of Tau Protein Phosphorylated at Threonine 231” note that p-tau 231 is found in postmortem brain tissue of Alzheimer's disease. In addition, p-tau 231 can also be detected in the CSF, leading researchers to believe that Alzheimer's disease can be diagnosed earlier.
In the Archives of Neurology study, the authors found that the p-tau 231 levels did not correlate with the severity of the dementia symptoms. However, p-tau 231 testing was more accurate in diagnosing Alzheimer's disease than t-tau testing, which tests for the total tau proteins present in the CSF. The authors also published another study, “Differentiated of Geriatric Major Depression From Alzheimer's Disease With CSF Tau Protein Phosphorylated at Threonine 231,” a year later in the American Journal of Psychiatry. They found that p-tau 231 levels were higher in Alzheimer's disease patients than geriatric major depression patients and healthy controls. The researchers found that in 87 percent of cases, p-tau 231 testing correctly identified probable Alzheimer's disease patients from major depression patients. The researchers also found that in 78 percent of cases, p-tau 231 testing correctly identified possible mild Alzheimer's disease from major depression.
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Elizabeth Stannard Gromisch received her bachelor’s of science degree in neuroscience from Trinity College in Hartford, CT in May 2009. She is the Hartford Women's Health Examiner and she writes about abuse on Suite 101.