Here in New Zealand a blood test is being developed that will allow people to find out whether they are likely to get Alzheimer's in the future. This is from The Press (in Christchurch) on April 7 2016.
They point out the pros and cons that will arise with this knowledge. An interesting dilemma.
Frankly I am not sure how I would react but I know I don't want to go through what George is going through and what my mother went through. However during this time there may also be breakthroughs in slowing down the disease.