Amyotrophic Lateral Sclerosis (ALS)

What is ALS?

Amyotrophic lateral sclerosis is a fatal type of motor neuron disease. It is characterized by progressive degeneration of nerve cells in the spinal cord and brain. It's often called Lou Gehrig's disease, after a famous baseball player who died from the disease. ALS it is one of the most devastating of the disorders that affects the function of nerves and muscles.

ALS does not affect mental functioning or the senses (such as seeing or hearing), and it is not contagious. Currently, there is no cure for this disease.

ALS most commonly affects people of any racial or ethnic group between the ages of 40 and 70, although it can occur at a younger age.

There are 2 main types of ALS:

  • Sporadic. This is the most common form of ALS in the U.S., making up 90% to 95% of all cases. These cases occur randomly, without any known cause, and there is no family history of ALS .

  • Familial. This form of ALS affects a small amount of people and is thought to be inherited.

What causes ALS?

Experts do not know the cause of ALS. In a few cases, genetics is involved. ALS research is looking into possible environmental causes of ALS.

Driving Toward a Cure for ALS | Science: Out of the Box

Johns Hopkins neurologist Jeffrey Rothstein explains how sticky DNA causes ALS. He shows how one drug he identified works to de-stick the DNA so it no longer globs up proteins in the cell.

What are the symptoms of ALS?

With ALS, you may first have weakness in a limb that develops over a matter of days or, more commonly, a few weeks. Then, several weeks to months later, weakness develops in another limb. Sometimes the initial problem can be one of slurred speech or trouble swallowing.

As ALS progresses, though, more and more symptoms are noticed. These are the most common symptoms of ALS:

  • Twitching and cramping of muscles, especially those in the hands and feet

  • Loss of motor control in the hands and arms

  • Impairment in the use of the arms and legs

  • Tripping and falling

  • Dropping things

  • Persistent fatigue

  • Uncontrollable periods of laughing or crying

  • Slurred or thick speech and trouble in projecting the voice

As the disease progresses, symptoms may include:

  • Trouble breathing

  • Trouble swallowing

  • Paralysis

The symptoms of ALS may look like other conditions or medical problems. Always see your healthcare provider for a diagnosis.

How is ALS diagnosed?

There is no specific test to diagnose ALS. Your healthcare provider will consider your medical history and symptoms and will do certain tests to rule out other conditions including:

  • Lab tests. These include blood and urine studies and thyroid functioning tests.

  • Muscle or nerve biopsy. In this procedure, your doctor removes a sample of tissue or cells from the body and examines it under a microscope.

  • Spinal tap (also called a lumbar puncture). In this test, your doctor places a special needle into the lower back, into the area around the spinal cord. There he or she can measure the pressure in the spinal canal and brain. Your doctor will remove a small amount of cerebral spinal fluid (CSF) and test it for an infection or other problems. CSF is the fluid that bathes the brain and spinal cord.


  • X-ray. This test uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.

  • Magnetic resonance imaging (MRI). This procedure  uses large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.

  • Electrodiagnostic tests, such as electromyography (EMG) and nerve conduction study (NCS). These studies evaluate and diagnose disorders of the muscles and motor neurons. Your doctor inserts electrodes into the muscle, or places them on the skin overlying a muscle or muscle group to record electrical activity and muscle responses.

What are the complications of ALS?

There is no cure for ALS. Over a period of 3 to 5 years, the disease will progress, making voluntary movements of arms and legs impossible. In time, you will need help with personal care, eating, and mobility. Movement of the diaphragm for breathing is also impaired. You may need a ventilator for breathing. Most people with ALS die from respiratory failure.

How is ALS treated?

For most people with ALS, the main treatment may involve the management of symptoms, This may include physical, occupational, speech, respiratory, and nutritional therapies. Some medicines, and heat or whirlpool therapy may help relieve muscle cramping. Exercise, in moderation, may help maintain muscle strength and function.

There are currently four FDA-approved drugs designated as disease modifying agents.  

  • Riluzole is an oral medication known to have effects on the disease and has been prescribed to ALS patients for over 25 years.
  • Edaravone was approved as a treatment for ALS by intravenous infusion in 2017, and an oral form of this medication was approved in 2022.
  • Sodium Phenylbutyrate/Taurursodiol, an oral medication, was approved for use in ALS patients in September 2022.
  • Tofersen, a medication administered by an intrathecal route, was approved in May 2023 for the treatment of ALS associated with an inherited mutation in the SOD1 gene.

Managing the symptoms of ALS is a process that is challenging for you, your caregivers, and your medical team. However, it’s important to know that there are many community resources available for support and assistance.

Researchers are conducting studies to increase their understanding of genes that may cause the disease, mechanisms that can trigger motor neurons to degenerate in ALS, and approaches to stop the progress leading to cell death.

ALS Clinical Trials

Dr. Maragakis speaking with a research participant
Clinical trials are essential to understanding ALS and developing effective treatments. Our team of investigators, nurses, and clinical research staff have over 100 years of combined experience in ALS clinical research.

Living with ALS

ALS will eventually lead to disability and death. Although your ability to move and breathe independently will be affected, your intelligence and ability to think is not. You and your family will work closely with your healthcare provider to manage symptoms as they develop. Use of the medicine may prolong your life by a few months, particularly if you have trouble swallowing. Discuss ways to make living spaces more accessible, and use of mobility devices and wheelchairs. It’s very important to discuss end-of-life decisions with your loved ones.

When should I call my healthcare provider?

It is important that you keep your healthcare provider informed about new symptoms so she or he can recommend therapies and community resources appropriately. Most importantly, call your healthcare provider if you start to have trouble breathing.

Key points

  • ALS is a fatal motor neuron disease. It is characterized by progressive degeneration of nerve cells in the spinal cord and brain.

  • ALS affects voluntary control of arms and legs, and leads to trouble breathing.

  • ALS does not affect intelligence, thinking, seeing, or hearing.

  • There is no known cure for ALS.

  • Treatment of ALS focuses on managing or minimizing symptoms as much as possible.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • Bring someone with you to help you ask questions and remember what your provider tells you.

  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

  • Ask if your condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if you do not take the medicine or have the test or procedure.

  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your provider if you have questions.

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