SNM: β-Amyloid Plaque Build-Up May Predict Alzheimer's

Build-up of plaques seen in healthy adults and in individuals with mild cognitive impairment

TUESDAY, June 7 (HealthDay News) -- The presence of β-amyloid (Aβ) plaques is associated with reduced processing speed, and may indicate progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD), according to three studies presented at the annual meeting of the Society of Nuclear Medicine, held from June 4 to 8 in San Antonio.

Michael D. Devous, Ph.D., from the University of Texas Southwestern Medical Center in Dallas, and colleagues examined the time course, regional distribution, and cognitive consequences of Aβ deposition in 137 healthy adults aged 30 to 89 years. Participants underwent positron emission tomography (PET) with F-18 florbetapir. Aβ deposition varied with age, from small increases in the prefrontal and parietal cortices to large increases in the anterior and posterior cingulate and percuneus. Larger increases and greater variability were seen in adults aged 60 and older. These age-associated increases were correlated with reduced processing speeds.

In another study, Christopher C. Rowe, M.D., from Austin Hospital in Melbourne, Australia, and colleagues used a spectrum of biochemical and neuroimaging biomarkers to assess the development of AD in an elderly population. Of the individuals with MCI who tested positive for 11C Pittsburg compound B (PiB), 54 percent progressed to AD compared to 13 percent of PiB-negative individuals with MCI. In a third study, Kevin Ong, M.D., also from Austin Hospital, and colleagues found that Aβ-positive MCI individuals were seven times more likely to convert to AD in a year compared to Aβ-negative individuals with MCI.

"Amyloid imaging with PET scans can help to ascertain the likelihood that individuals will deteriorate cognitively within a few years, thereby enabling more efficient channeling of health care resources," Ong said in a statement.

Several of the study authors disclosed financial ties to the pharmaceutical and health care industries.

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