This will resolve based on mainstream media reports. Any kind of dementia counts. Outside speculation does not count, unless the evidence is so strong that mainstream media consensus emerges.
I do not bet on my markets.
That is a fair concern. I think the bar has to be higher than a letter from 70 physicians stating Trump should be evaluated for such conditions
https://www.cnn.com/2018/01/13/health/trump-mental-health-exam/index.html
or a letter of concern by 350 health professionals
since those have already happened. I also do not want impossible criteria. Ways that this could resolve to YES would include florid symptoms that leave little doubt, a leak of medical information deemed credible by mainstream press, or a quantitative analysis of his speech patterns such as this one on Ronald Reagan.
Parsing Ronald Reagan’s Words for Early Signs of Alzheimer’s https://www.nytimes.com/2015/03/31/health/parsing-ronald-reagans-words-for-early-signs-of-alzheimers.html?smid=nytcore-android-share
I am open to any suggestions for clear resolution criteria.