Researchers have finally zoomed in on three marker proteins which can clearly foretell the possibility of Alzheimer's disease in earlier years.

The three proteins can be detected through analysing the cerebrospinal fluid drawn from the patients. These proteins will not only predict Alzheimer's disease long before symptoms start but could also suggest how fast the disease is progressing.

For the study, the researchers measured the levels of total tau protein, phosphorylated tau and amyloid protein in the cerebrospinal (CSF) of 102 people with Alzheimer's, 200 people with mild cognitive impairment and 114 individuals without the disease.

They found the first signs of the disease in what they called an "Alzheimer's disease signature" present in 90 percent of the Alzheimer's patients, 72 percent of those with mild cognitive impairment (MCI) and 36 percent of those who had no cognitive impairments.

A signature consisting of low amyloid levels and high phosphorylated tau levels identified patients with MCI who progressed to Alzheimer's with 100 percent accuracy, the team said.

The fact that the signature was also found in individuals with no sign of cognitive impairment underlines the likelihood that Alzheimer's disease has started long before it became symptomatic, the authors said in the findings published in the latest issue of the Archives of Neurology.

An accompanying editorial endorsed the findings, by noting that CSF (cerebrospinal fluid) analyses of A1-42, T-tau, and P-tau becoming a definitive diagnosis of AD was important for counseling patients about such concerns as work, driving, and making other lifestyle changes.

"This just reinforces the recommendation by (Alzheimer's working groups) that biomarkers can actually be incorporated today into clinical practice in order to add a certain piece to the diagnosis if patients are already presenting with something that looks like Alzheimer's," says Maria C. Carrillo, senior director of medical and scientific relations at the Alzheimer's Association.