Amyotrophic lateral sclerosis, or ALS, is a progressive nervous system (neurological) disease that destroys nerve cells and causes disability.
Doctors usually don't know why ALS occurs and some cases are inherited.
ALS often begins with muscle twitching and weakness in a limb, or slurred speech. Eventually, ALS affects control of the muscles needed to move, speak, eat and breathe. There is no cure for ALS, and eventually the disease is fatal.
Key word: define amyotrophic sclerosis