Brain & Nervous System Health Center

What is amyotrophic lateral sclerosis?

Amyotrophic lateral sclerosis, or ALS, is a disease in which certain nerve cells in the brain and spinal cord slowly die. These nerve cells are called motor neurons, and they control the muscles that allow you to move the parts of your body. ALS is also called Lou Gehrig’s disease.

People with ALS gradually become more disabled. How quickly the disease gets worse is different for everyone. Some people live with ALS for several years. But over time, ALS makes it hard to walk, speak, eat, swallow, and breathe. These problems can lead to injury, illness, and eventually death. In most cases, death will occur within 3 to 5 years after symptoms begin, although some people do live for many years, even decades.

It can be very scary to learn that you have ALS. Talking with your doctor, getting counseling, or joining a support group may help you deal with your feelings. Your family members may also need support or counseling as your disease gets worse.

ALS is rare. Each year in the United States and most of the world, only 1 to 2 people out of 100,000 get ALS. Men get ALS slightly more often than women do. ALS can occur at any age, but it most often starts in middle-aged and older adults.¹

What causes ALS?

Doctors don't know what causes ALS. In about 1 case out of 10, it runs in families.¹ This means that 9 times out of 10, a person with ALS doesn't have a family member with the disease.

What are the symptoms?

The first sign of ALS is often weakness in one leg, one hand, the face, or the tongue. The weakness slowly spreads to both arms and both legs. This happens because as the motor neurons slowly die, they stop sending signals to the muscles. So the muscles don't have anything telling them to move. Over time, with no signals from the motor neurons telling the muscles to move, the muscles get weaker and smaller.

Over time, ALS also causes:

• Muscle twitching.
• Trouble using your hands and fingers to do tasks.
• Problems with speaking, swallowing, eating, walking, and breathing.

ALS doesn't cause numbness, tingling, or loss of feeling.

Respiratory problems are the most common serious complication of ALS. As the muscles in the throat and chest weaken, swallowing, coughing, and breathing problems tend to get worse. Pneumonia, pulmonary embolism, lung failure, and heart failure (probably caused by weak breathing) are the most common causes of death.

How is ALS diagnosed?

It can be hard for your doctor to tell if you have ALS. It may not be clear that you have the disease until symptoms get worse or until your doctor has done more testing. To find out if you have ALS, your doctor will do a physical exam and will ask you about your symptoms and past health. You will also have tests that show how your muscles and nerves are working.