What is ALS?

Amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig's disease, is a progressive neurodegenerative disease that attacks motor neurons in the brain (upper motor neurons) and spinal cord (lower motor neurons).

These motor neurons control the movement of voluntary muscles. When the motor neurons can no longer send impulses to the muscles due to ALS, the muscles begin to waste away (atrophy), causing increased muscle weakness. Motor neuron, or nerve cell, death makes it impossible for the brain to control muscles or signal them to move.

There are several classifications of ALS. These include:

• Classical ALS, affecting both lower and upper motor neurons
• Primary Lateral Sclerosis (PLS), affecting only the upper motor neurons
• Progressive Bulbar Palsy (PBP or Bulbar Onset), a version of ALS that starts with difficulties swallowing, chewing and speaking and affects approximately 25% of ALS patients
• Progressive Muscular Atrophy (PMA), affecting only the lower motor neurons
• Familial ALS, a genetic version of ALS that affects five to ten percent of ALS patients in the U.S.
• Symptoms of ALS include twitching and cramping of muscles (called fasciculation), loss of motor control in hands and arms, impaired use of the arms and legs, weakness and fatigue, tripping and falling, dropping things, slurred or thick speech and difficulty breathing or swallowing.

In most cases, ALS patients do not experience impaired intellectual reasoning, vision or hearing. Eye and bladder muscles, along with sexual function and drive, are not normally affected.

ALS is diagnosed using a variety of tests and examinations, including laboratory tests, muscle and nerve biopsy, spinal tap, X-rays, MRI's and electrodiagnostic tests.

For more information about ALS and what ALSTDI is doing to fight this disease, please visit the ALS Therapy Development Institute website.