Amyotrophic Lateral Sclerosis (ALS)
What Is It?
Amyotrophic lateral sclerosis (ALS) causes a slow degeneration of nerve cells (called motor neurons) that control muscle movements. As a result, people with ALS gradually lose the ability to control their muscles. Fortunately, their capacity to think and remember things usually is not affected. ALS is also known as Lou Gehrig's disease, after the famous U.S. baseball player who developed the disease.
There are several diseases besides ALS that gradually destroy motor neurons (called motor neuron diseases), although ALS is the most common motor neuron disease. The different diseases have different prognoses.