Of all the ways the body can go wrong, A.L.S. is one of the most frightening. It begins subtly — a twitching muscle, a cough when you swallow or a clumsy hand. But then it progresses. Motor neurons degenerate and die. You lose the ability to talk, to eat and ultimately to breathe. There is no cure. Treatment will slow progression somewhat, but not enough.

A diagnosis of A.L.S., or amyotrophic lateral sclerosis, begins a race against the clock. What do you do to make yourself heard before you are rendered voiceless? How do you find a trial or a treatment to extend time long enough to be there for the next scientific advance?

I rarely have time to probe the answers to these questions when I take care of people with A.L.S. in the intensive care unit or long-term hospital ward. But the faces stay with me. I remember a woman who just wanted to go to the beach once more, to eat a lobster roll before she could no longer swallow. I remember a young man with an elaborate sound system in his hospital room whose wife had left him; there was no one to take care of him at home, and so he would live out his days in a nursing facility.

In contrast to the experience of those with cancer, for whom there is often the promise of a new drug around the bend, there are relatively few therapies for A.L.S. Perhaps that is why I became so interested recently in the vigorous debate over the possible approval by the Food and Drug Administration of a new treatment for A.L.S.: a stem cell therapy called NurOwn developed by BrainStorm Cell Therapeutics. Some patients who had early access to the drug described improvement like being able to pick up a remote control for the first time in months or being able to walk through the grass.