The finding was published on Monday, in Archives of General Psychiatry, an American Medical Association journal.

　　The researchers gathered data of 116 people with mild cognitive impairment (MCI) who developed Alzheimer's disease within two years, 204 patients with the condition who didn't develop Alzheimer's and 197 people with no cognitive problems.

　　Mild cognitive impairment is usually marked by difficulties with short-term memory, such as losing your train of thought repeatedly or having trouble remembering what you did yesterday, according to the study.

　　After assessing them by biomarker tests and cognitive measures, the researcher found the cognitive markers can forecast the variance.

　　"Remarkably, they accounted for nearly 50% of the predictive variance," said Dr. Gomar of Centro de Investigation Biomedica en Red de Salud Mental, Barcelona, who led the research.

　　Mild cognitive impairment at the start of the study was a stronger predictor of Alzheimer's than most biomarkers, the researchers concluded.