Stages of ALS
Once ALS starts, it almost always progresses, eventually taking away the ability to walk, dress, write, speak, swallow, and breathe, and shortening the life span. The onset of ALS often involves muscle weakness or stiffness as early symptoms. Progression of weakness, wasting, and paralysis of the muscles of the limbs and trunk, as well as those that control vital functions such as speech, swallowing, and breathing, generally follows.
How fast and in what order this occurs is very different from person to person. While the average survival time is three years, about 20 percent of people with ALS live five years, 10 percent will survive 10 years and 5 percent will live 20 years or longer.
Progression is not always a straight line in an individual, either. It is not uncommon to have periods lasting weeks to months where there is very little or no loss of function. There are even very rare examples in which there is significant improvement and recovery of lost function. These ALS "arrests" and "reversals" are, unfortunately, usually transient. Less than 1 percent of people with ALS will have significant improvement in function lasting 12 months or longer.