What is amyotrophic lateral sclerosis (ALS)?
ALS is a progressive disease that causes the patient to slowly lose control of muscles needed to move, speak and breathe. It usually begins with muscle twitching, weakness or stiffness in an arm or leg and slurred speech. This rare neurological disease (affects the nerves) mainly damages nerve cells that control voluntary muscle movements such as chewing, walking or talking. There is no cure or treatment; the cause is unknown; and ALS is always fatal, usually from inability to breathe (respiratory failure). The average period from first symptoms to death is three to five years. However, about 10% of ALS patients live 10 years or more; 5% live 20 years or longer.
ALS is one of the motor neuron diseases. Motor neurons are nerve cells that extend from the brain to the spinal cord and to muscles throughout the body. ALS causes deterioration or degeneration of motor neurons. As motor neurons degenerate, they no longer send messages to muscles. The muscles weaken and atrophy (waste away), and the brain loses the ability to initiate and control voluntary muscle movements.