One of the leading activists of Dignity in Dying, Alex Pandolfo, was diagnosed with a form of Alzheimer's 10 years ago. He considered committing suicide, because he had seen the devastation the disease caused for his parents. But he then found about LifeCircle (now Pegasos) in Switzerland and went to visit them and got the 'green light' as he calls it. And he says it saved his life- because he knows that he will have the choice, before the disease gets too bad. 10 years later, he is still doing well. Some forms of memory loss, but fully compos mentis.
His true dilemma is, 10 years later, to know when to make the decision, as he can't wait until he can no longer demonstrate that he has capacity to decide, clearly- despite having his case approved. His other dilemma is about his partner- he doesn't want her to accompany him, for fear she would be prosecuted and treated like a criminal. If so, I will be there with and for him, as promised.