Jennifer Rose V. Molano, MD reviewing Donohue MC et al. JAMA 2017 Jun 13. Visser PJ and Tijms B. JAMA 2017 Jun 13.

Elevated brain amyloid in initially cognitively normal individuals is associated with worse cognitive performance and greater brain atrophy over time.

Researchers evaluated the longitudinal effects of elevated brain amyloid levels compared with the effects of normal amyloid levels in 445 initially cognitively normal individuals (mean age, 74; mean education level, 16 years; 52% women). Mean follow-up was 4 years; maximum follow-up was 10 years. The study was partially manufacturer-supported. Elevated brain amyloid was seen in 202 individuals based on positron emission tomography amyloid imaging or cerebrospinal fluid (CSF) amyloid levels.

Those with elevated amyloid versus normal amyloid at baseline had similar cognitive performance on global screening mental status examination scores and a composite score of episodic memory, orientation, and executive function. The elevated-amyloid group had a higher rate of cognitive decline 4 years later compared with the normal-amyloid group. A diagnosis of mild cognitive impairment also was more common in the elevated-amyloid group 4 years after baseline. The mean CSF tau level was higher in the elevated-amyloid group than in the normal-amyloid group at baseline, but the rate of change in CSF tau level was similar in the two groups. Brain atrophy based on ventricular and hippocampal volume was similar between the two groups at baseline. The rate of brain atrophy was more pronounced in the elevated-amyloid group than in the normal-amyloid group.

Citation(s):

Donohue MC et al. Association between elevated brain amyloid and subsequent cognitive decline among cognitively normal persons. JAMA 2017 Jun 13; 317:2305.

Visser PJ and Tijms B.Brain amyloid pathology and cognitive function: Alzheimer disease without dementia? JAMA 2017 Jun 13; 317:2285.

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