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. Author manuscript; available in PMC: 2020 Jul 1.
Published in final edited form as: Alzheimers Dement. 2019 Jul;15(7):907–916. doi: 10.1016/j.jalz.2019.04.005

Figure 1: Alternative Hypotheses for How Cognitive Reserve Relates to Mortality.

Figure 1:

In the figures below, solid curves represent Pathology (yellow), True Cognitive Ability (blue) and Cognitive Assessment (black). Dementia or AD diagnosis occurs when True Cognitive Ability reaches a certain severity (red dotted line). Death occurs when True Cognitive Ability reaches a certain severity (green line). Dashed curves represent the impact of cognitive reserve on Cognitive Assessment and/or True Cognitive Ability. The left panel displays cognitive reserve as diagnostic bias – in this scenario the Cognitive Assessment curve is shifted forward, meaning cognitive reserve delays age of diagnosis, but no meaningful changes in True Cognitive Ability or age at death occurs. The right panel displays cognitive reserve as having a meaningful protective effect on True Cognitive Ability and age at death.