Amyotrophic Lateral Sclerosis (ALS)

Overview

Amyotrophic lateral sclerosis (ALS) is a brain and nerve disease that affects motor neurons, the nerve cells in the brain and spinal cord that control movements a person chooses to make, like walking or lifting, as well as breathing. This causes the muscles to weaken, start to twitch (fasciculations), and waste away (atrophy). Eventually, the brain and spinal cord lose their ability to send signals that start and control voluntary movements such as walking, talking, and chewing, as well as breathing.

Signs and Symptoms

Although ALS can happen at any age, symptoms most commonly develop between the ages of 55 and 75. ALS is progressive, meaning symptoms get worse over time.

Early Symptoms

Early symptoms of ALS include:

• Muscle twitches in the arm, leg, shoulder, or tongue
• Muscle cramps
• Tight and stiff muscles (spasticity)
• Muscle weakness affecting an arm, a leg, the hands, feet, or neck
• Slurred and nasal speech
• Difficulty chewing or swallowing

In most cases, the first symptoms of ALS will be new weakness in an arm or leg. However, in about 20-30% of cases, muscles that allow chewing, speaking or swallowing (called bulbar muscles) may be impacted first.

As the Disorder Progresses

As ALS progresses, muscle weakness and muscle wasting (atrophy) spread to other parts of the body. People with ALS may develop problems with:

• Chewing food and swallowing (dysphagia): This can make it hard to for people with ALS to get the nutrients their body needs
• Drooling (sialorrhea)
• Speaking or forming words (dysarthria)
• Breathing (dyspnea): As the breathing muscles weaken, a person with ALS may feel short of breath during physical activity or have trouble breathing at night or when lying down. Most people with ALS die because they lose the ability to breathe.
• Coughing: As breathing muscles weaken, people with ALS may not be able to cough hard enough to clear their throat
• Unintended crying, laughing, or other emotional displays (pseudobulbar affect, or PBA)
• Constipation: Often related to reduced mobility and dietary changes, not from direct motor neuron loss
• Difficulty maintaining a healthy weight and getting enough nutrients

Eventually, people with ALS become unable to stand or walk, get in or out of bed on their own, use their hands and arms, or breathe on their own.

Mental Health and Cognition

ALS affects the body in several serious ways beyond its effects on motor neurons and muscles.

Although less common, people with ALS may also experience problems with language or decision-making. Some develop a form of dementia known as frontotemporal dementia (FTD), a type of dementia that affects personality, behavior, and language. Mild thinking or memory problems affect up to half of all people with ALS.

Because people with ALS usually remain able to reason, remember, and understand, people with ALS are aware of their progressive loss of function. This can lead to feelings of anxiety and depression for both the person with ALS and their loved ones.

Causes and Risk Factors

ALS primarily affects motor neurons, the nerve cells in the brain and spinal cord that control voluntary muscle movement and breathing. As motor neurons degenerate and die, they stop sending messages to the muscles.

Key risk factors include:

• Biological sex: Men are slightly more likely to develop ALS than women, but at older ages, men and women are equally likely to be diagnosed with ALS.
• Race and ethnicity: ALS is more common in White people, especially those who are not Hispanic, but it can affect people of all races and ethnicities.
• Military service: Some studies suggest military veterans are about 1.5 to 2 times more likely to develop ALS, but the reason is not fully understood. Possible risk factors for veterans may include exposure to lead, pesticides, and other harmful chemicals in the environment, though no single cause has been confirmed.
• Head injury: Some studies have shown that head injury can be associated with higher risk for ALS, but more research is needed to understand this connection.

Genetic Factors

Doctors consider nearly all ALS cases sporadic, meaning the disorder seems to happen at random with no clearly associated risk factors and no family history. About 10% of all ALS cases are familial (also called inherited or genetic). Although family members of people with ALS are at an increased risk for the disorder, the overall risk is very low— most won’t develop ALS.

Mutations in more than a dozen genes have been found to cause familial ALS. For example:

• Mutations in the C9orf72 gene, a gene that affects how cells recycle waste materials, cause about 25%–40% of all familial cases and a small number of sporadic cases
• Mutations in the SOD1 gene, which protects the cell from reactive oxygen species toxicity, cause another 12%–20% of familial cases

Diagnosis

There’s no one single test that can definitively diagnose ALS. On average, doctors diagnose most people with ALS about 12 months after the first symptoms begin, though this can take longer.

Getting an accurate ALS diagnosis as soon as possible is important. Some ALS treatments, like riluzole, may work better when started early. A doctor familiar with ALS can diagnose the condition early.

Diagnosis methods include:

• A physical exam and taking the person’s full medical history
• A neurologic exam to test reflexes, muscle strength, coordination, and other responses
• Repeat these tests at over time to track how the disease is getting worse over time

Key Diagnostic Tests

Electromyography (EMG) tests how well nerves and muscles are functioning. An EMG can include:

• A nerve conduction study, which checks how well electrical signals travel through nerves and muscles
• A needle exam, which uses a small needle to detect electrical activity inside the muscle

Magnetic resonance imaging (MRI) uses a magnetic field and radio waves to produce detailed images of the brain and spinal cord. MRI helps rule out other disorders that may look like ALS.

Additional Tests

Other tests that may rule out the possibility of other disorders:

• Blood and urine tests
• A spinal tap (lumbar puncture) to test the fluid that surrounds the brain and spinal cord (CSF)
• Muscle biopsy, where a small sample of muscle tissue is removed and examined in a lab

Treatment and Management

The U.S. Food and Drug Administration (FDA) has approved several drugs for ALS that may extend life, slow the disease, or help manage symptoms. There is currently no known treatment that stops or reverses the progression of ALS.

Most people with ALS die because their breathing muscles stop working (respiratory failure), usually within three to five years of symptoms first appearing. About one in 10 people survive for 10 years or more.

Multidisciplinary Care Teams

Integrated, multidisciplinary teams of healthcare professionals working together can provide the best supportive healthcare. These teams can design a personal treatment plan and provide special equipment aimed at keeping people as mobile, comfortable, and independent as possible. They may include:

• Physicians and pharmacists, including neurologists and palliative care specialists
• Physical, occupational, speech, and respiratory therapists
• Nutritionists
• Social workers
• Clinical psychologists
• Home care and hospice nurses

FDA-Approved Medicines

Doctors may use the following medicines approved by the FDA to support a treatment plan for ALS:

• Riluzole (Rilutek) is an oral medicine believed to protect motor neurons by lowering levels of glutamate, a chemical which carries messages between nerve cells and motor neurons. Clinical trials showed that riluzole may extend survival by a few months. The thickened liquid form (Tiglutik) or the dissolving tablet (Exservan) may be better for people who have trouble swallowing.
• Edaravone (Radicava) is an antioxidant taken by mouth or given through an IV.Some studies suggest it may slow the loss of physical function in certain people with ALS, though the evidence is limited. Radicava ORS is a form of edaravone that can be taken by the mouth or through a feeding tube.
• Tofersen (Qalsody) is given through a spinal injection to people with ALS who have a confirmed mutation in the SOD1 gene. It may work by lowering the abnormal SOD1 protein that damages nerve cells, though researchers are still studying how well it works.

A doctor may also prescribe other medicines to help manage symptoms such as muscle cramps and stiffness, drooling, buildup of mucus, and uncontrolled crying, laughing, or other emotional displays (PBA). Medicines may also help with pain, depression, sleep problems, or constipation.

Living With ALS

A treatment plan for ALS usually includes rehabilitation designed to fit a person’s specific needs.

Physical function and daily life

Physical therapy can help people with ALS keep function and movement, lower their risk of falls and joint pain, and maximize their independence. Light exercises such as walking, swimming, or using a stationary exercise bike, along with stretching exercises may help some people keep their muscle strength and function. A physical therapist can help decide what activity is safe for each person. Occupational therapists can suggest assistive devices for feeding, bathing, and grooming.

Speech and communication

Speech therapists can help people with ALS speak louder, more clearly, and find new ways to communicate as speech becomes harder. Computer-based speech synthesizers can use eye-tracking technology to let a person choose words or letters on a screen to communicate, even when they can no longer speak or use their hands. People with ALS sometimes use voice banking, a process that stores their own voice for future use in computer-based speech synthesizers.

A brain-computer interface (BCI) is a system that allows people to communicate or control equipment such as a wheelchair using only brain activity. Researchers are working to make BCIs smaller, more mobile, and easier to use for people with severe paralysis or visual impairments.

Nutrition, breathing, and feeding

Nutritionists and registered dietitians can help plan small, nutritious meals throughout the day. When swallowing becomes too difficult or unsafe, a feeding tube can help the person get enough nutrition and lower the risk of choking and pneumonia.

Noninvasive ventilation is a type of breathing support usually delivered through a mask over the nose, mouth, or both. At first, noninvasive ventilation may only be necessary at night, but people may eventually need it full time. As the disorder progresses, the person may need the support of respirators (mechanical ventilators) to breathe. Devices are also available to help people cough more forcefully and keep their airways clear.

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on amyotrophic lateral sclerosis.

Find Treatment

Under the Accelerating Access to Critical Therapies for ALS Act (ACT FOR ALS), NIH specifically funds research to help people with ALS access experimental treatments even if they do not qualify for clinical trials. Under ACT for ALS, NIH also funds the Access for ALL in ALS Consortium (ALL ALS), a community of two coordination centers and over 30 research sites across the U.S. and Puerto Rico. These sites track how ALS develops over time and collects biological samples to help identify markers of the disease.

Community Support

As ALS progresses, people need more and more help with daily activities. Being a caregiver for a person with ALS, while rewarding, can be challenging. It is important for caregivers to take care of themselves and to seek support when needed. Free and paid resources are available to provide home healthcare services and support.

The following organizations provide information and support for people living with ALS and their families:

• The ALS Association
• ALS Therapy Development Institute
• I AM ALS
• Les Turner ALS Foundation
• Project ALS
• Genetic and Rare Diseases (GARD) Information Center
• Eldercare Locator

How can I or my loved one help improve care for people with ALS?

National ALS Registry

The Centers for Disease Control and Prevention maintains the National ALS Registry. The Registry collects, manages, and analyzes data about people with ALS in the U.S. It establishes information about the number of ALS cases, collects demographic, occupational, and environmental exposure data, and notifies participants about research opportunities. People with ALS can add their information to the registry and sign up to receive more information.

Brain and Spinal Cord Donation

The NIH NeuroBioBank is a collaborative effort involving several brain banks across the U.S. that supply investigators with tissue from people with neurological and other disorders. Researchers need tissue from people with ALS to help advance critical research on the disorder. A single donated brain and/or spinal cord can potentially provide information for hundreds of studies. Potential donors can begin the enrollment process by visiting Learn How to Become a Brain Donor.

Note: This resource list is for informational purposes only. It is not comprehensive, and an organization’s inclusion does not constitute an endorsement by NIH.  

Research Information

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.  

NIH conducts and funds a large amount of research on the brain and nervous system, including disorders such as ALS.

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies. 

NINDS Phone Line

Call 1-800-352-9424 (toll free) Monday through Friday from 9AM to 5PM ET. People with hearing or speech impairments can dial 7-1-1 to access the free relay service.

Order publications from NINDS

The NINDS Publication Catalog offers printed materials on neurological disorders for patients, health professionals, and the general public. All materials are free of charge, and a downloadable PDF version is also available for most publications.

https://www.ninds.nih.gov/publications/amyotrophic-lateral-sclerosis