A chronic, progressive disease marked by gradual degeneration of the nerve cells in the central nervous system that control voluntary muscle movement. The disorder causes muscle weakness and atrophy; symptoms commonly appear in middle to late adulthood, with death in two to five years. The cause is unknown, and there is no known cure. Also called Lou Gehrig’s Disease, or Motor Neuron Disease. Literally, amyotrophic lateral sclerosis means without muscle nourishment, side (of spinal cord) hardening.
