I don't know how well I can help, but I noticed this post had no answers yet, so I will try. It must be difficult going through this when you have also seen your mom progress so fast. It is hopeful that you are still walking and are not losing muscle function as quickly as your mom did. As you know, everyone is different, but there are common threads as well. You have asked for others' experience of the progression, so I will relate my dad's chronology.
My dad lost strength in the muscles of his back and neck first (about 2 years ago), causing him to have difficulty lifting his head and sitting up, his legs and arms began to weaken, though he maintained some manipulation ability in his hands longer than the neurologist expected (possibly because he did exercises from the physical therapist daily). When he had difficulty swallowing and could not eat easily, he began to lose weight, which exacerbated muscle loss due to nerve degeneration. This is a major concern as far as life expectancy goes. For many people, a PEG tube surgically placed can provide nourishment directly and helps prevent weight loss and maintain good nutrition. He was able to speak until the end, though it was more difficult and he chose his words carefully and tired easily from conversation. He was saddened that he had less control over the pitch of his voice when he sang, as singing was a great joy to him....he sang anyway, and nobody cared that he wasn't in tune. It appeared my dad was doing pretty well with breathing capability, 70% just 2 months before he died, but this decreased rapidly. It seemed fairly sudden that he was unable to breathe sufficiently to sustain life. He was still able to walk(a short way with a walker), talk and do his buttons (slowly and with great struggle). He could still write, though it was fairly illegible. His stamina for any activity was increasingly shortened. Looking back, I think it was the breathing creeping up on him. It was hard to tell. Maybe he was tired throughout his entire body. Many people are able to use a bi-pap machine for breathing assistance, which keeps them going for months or years. I know of 2 (one being my dad) for whom the bi-pap did not work to keep the enough air going in and out. A tracheostomy with portable ventilator at this point is a choice that some PALS decide to do. This can extend life expectancy considerably, but requires full time care. Personally, I think the doctors wait too long to give people the bi-pap (because of insurance guidelines?) It is my thought that not getting enough oxygen in and carbon dioxide out, even when you aren't yet on death's door, can weaken a PALS and rob what little energy you might otherwise still have left. Demand it sooner if you can.
Well, I sure got going there...on vacation so I have a lot of loose time this week.
