β-Amyloid Deposition Seen in Some Healthy Older Adults
Greater amyloid burden associated with APOE status; linked to poorer cognitive performance
THURSDAY, Feb. 2 (HealthDay News) -- Elevated β-amyloid (Aβ) deposition is seen in some healthy older adults and is associated with worse cognitive performance, according to a study published online Feb. 1 in Neurology.
To investigate the relationship between elevated amyloid and cognitive performance, Karen M. Rodrigue, Ph.D., from the University of Texas at Dallas, and colleagues studied 137 well-screened and cognitively normal adults (aged 30 to 89) to map the cortical distribution of Aβ. The participants underwent Aβ positron emission tomography imaging with radiotracer 18F-florbetapir, and the Aβ load was estimated based on eight cortical regions. Participants underwent APOE genotyping and were tested for processing speed, working memory, fluid reasoning, episodic memory, and verbal ability.
The researchers found that Aβ deposition was distributed differentially across the cortex, and deposition rates varied with age across cortical brain regions. Markedly elevated Aβ deposition was seen in a subset of cognitively normal adults aged 60 years or older, and 38 percent of this subset were APOE ε4 carriers, compared with 15 percent of older participants without Aβ elevation. Aβ burden was linked to poorer cognitive performance as measured by processing speed, working memory, and reasoning.
"Even in a highly selected lifespan sample of adults, Aβ deposition is apparent in some adults and is influenced by APOE status," the authors write.
Several authors disclosed financial ties to pharmaceutical companies, including Avid Radiopharmaceuticals, which donated the ligand used in the study.