. Comprehension of an Elevated Amyloid Positron Emission Tomography Biomarker Result by Cognitively Normal Older Adults. JAMA Neurol. 2018 Jan 1;75(1):44-50. PubMed.


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  1. Overall, I think this addresses an important issue given the rise of molecular imaging. Although the authors reported that the smallest number of responses indicated “imminent” risk or were “diagnostic of” Alzheimer’s, this constituted 12 percent of the sample, which is not insignificant, especially when one considers 1) that these individuals received insightful education (which is more than one would expect from a primary care provider should this ever become more widely used clinically), and 2) the burgeoning number of people entering clinical trials that require amyloid PET.

    I also felt the authors’ recommendation to explain “why a dimensional biomarker is converted to a categorical classification” was right on target. It is not intuitive that an amyloid PET scan would simply be “positive or negative.” Amyloid buildup is certainly not all or nothing, and the patient responses are telling us that people more likely understand quantities, or some quantitative modifier (e.g., mild, moderate, severe). I was not surprised at the uncertainties the authors uncovered in the participants and it is consistent with a related study we did using just a hypothetical scenario, very brief education, and a multiple-choice questionnaire. A question we asked that was not included in the current study was, what did the patients intend to do now that they had the results? Would they discuss them with their doctors? Would they buy long-term-care insurance? Did this make them anxious or depressed, etc.? 

    View all comments by Richard Caselli
  2. The only surprising thing to me was that, despite extensive education on the meaning of a positive and negative amyloid scan, only 62 percent of participants appeared to correctly grasp the significance of a positive scan as putting them at an increased risk for developing AD symptoms and signs. The education they received in the course of this study is undoubtedly more than one would get in general clinical practice, so this reinforces to me that release of amyloid PET results in cognitively normal persons is “not ready for prime time”—that is, for widespread clinical application.

    View all comments by John Ringman

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  1. Among the Healthy, a Positive Amyloid Scan Prompts Questions About Risk