A lot of people have enough of a sense of responsibility to donate blood, or donate their organs.

I've long had the suspicion that much of what is called Alzheimers or dementia is some form of prion disease. This study doesn't show that, exactly, but it shows that abnormal proteins may be directly correlated.

So - and I'm not saying this is the case - but suppose that the abnormal proteins identified in this study could be transmitted by blood transfusions or organ transplants. Wouldn't that itself be enough for your diagnosis to help you personally not transmit those proteins to someone else?

If your attitude is that no one else in the world matters once you get a bad diagnosis, then nothing really mattered to you before. Other people are working day and night trying to cure you, so there's no cause for that level of nihilism. You may as well try to help from the vantage point you have.