Amyotrophic lateral sclerosis (ALS) is a degenerative disease that affects the brain and spinal cord. It causes a worsening loss of voluntary muscle control affecting movements like talking, swallowing, and walking.

There is currently no cure for ALS. However, treatments are available that can reduce symptoms and may help people with ALS to live longer.

The famous baseball player Lou Gehrig developed symptoms of the condition in the 1930s, and that’s why it’s also known as Lou Gehrig’s disease.

ALS can be classified as either sporadic or familial. Most cases are sporadic. That means no specific cause is known.

Familial ALS happens when the condition is inherited from a parent. Only about 5% to 10% of ALS cases are familial.

Other causes of ALS aren’t well understood. Some factors that scientists think might contribute to ALS include:

  • free radical damage
  • imbalances in the chemical messenger glutamate
  • protein abnormalities, like misfolding
  • nerve inflammation

Military veterans are thought to be at higher risk for ALS, though the reasons for this are unclear. Some research suggests that smoking is a risk factor for ALS. Research on other possible environmental triggers is ongoing.

Demographic factors

  • Age: The likelihood of receiving an ALS diagnosis increases with age. The onset of symptoms in ALS usually occurs between the ages of 55 and 75, although symptoms can occur earlier.
  • Sex: According to statistics that group people into male and female categories, ALS is more common among males than females.
  • Race and ethnicity: Research suggests that white people are more likely to receive an ALS diagnosis than people of other racial or ethnic groups. According to the National Organization for Rare Diseases, more studies are needed to understand who’s affected by ALS globally.

Every year, about 5,000 people in the United States receive an ALS diagnosis. Around 30,000 people in the U.S. are currently living with the condition. ALS affects people in all racial, social, and economic groups.

A 2016 study suggests that ALS is becoming more common. This may be because the population is aging.

Both sporadic and familial ALS are associated with a progressive loss of motor neurons. As motor neurons become damaged, a person with ALS will start to have difficulty with voluntary movements in their limbs, mouth, or throat.

There are two main types of ALS. Each one is associated with a different set of symptoms at the time of diagnosis.

Limb onset

Around 70% of people with ALS have what’s known as “limb onset” ALS. This means that symptoms first appear in the arms or legs.

Symptoms in the arms (upper limb onset) include:

  • weakness in hands
  • stiff arms or hands
  • cramps in arms or hands
  • loss of dexterity, fumbling, or dropping objects

Symptoms in the legs (lower limb onset) include:

  • trouble with walking or running
  • tripping or stumbling
  • difficulty lifting the front half of the foot when walking, known as foot drop

Early symptoms are usually in either the arms or the legs, not both. Limb onset ALS usually progresses more slowly than other types.

Bulbar onset

“Bulbar onset” ALS is less common. In this type, ALS first affects a part of the brainstem known as the corticobulbar area. Symptoms include difficulty with speech and swallowing and muscle spasms in the face or throat.

There are also rare sub-types of ALS that are defined by other symptoms present at the time of diagnosis. These include respiratory onset ALS when difficulties with the breathing muscles are the earliest sign of illness.

Upper and lower motor neurons

You have two main types of motor neurons in your body: upper motor neurons and lower motor neurons. They work together to allow your brain to communicate with your muscles to make voluntary movements possible.

For example, when you decide to move your finger, your upper motor neurons first send signals from your brain to your spinal cord. Then, lower motor neurons carry signals from the spinal cord to the muscles that move your finger.

By definition, ALS affects both upper and lower motor neurons. But the condition may start by affecting one type more than the other, either the upper or the lower. Each type can result in different symptoms.

Symptoms of upper motor neuron disease include:

  • involuntary rhythmic muscle contractions, known as clonus
  • rigid muscles (spacticity)
  • overactive reflexes

Symptoms of lower motor neuron disease include:

Weakness happens with both types of motor neuron disease.


The earliest symptoms of ALS may include small muscle twitches in your:

  • mouth
  • throat
  • face
  • limbs

But it’s typical to notice muscle twitches from time to time. They’re usually not a cause for concern. In early ALS, muscle twitches are likely to become more frequent over time.

Other early signs of ALS may include difficulty performing some everyday tasks. This could mean difficulty climbing stairs or getting up from a chair. It’s also possible to have difficulty speaking or swallowing, or weakness in the arms, hands, or legs. You may also notice cramping.

Early symptoms tend to be asymmetrical, which means they only happen on one side.

As the condition progresses, the symptoms generally spread to both sides of the body. Muscle weakness, weight loss, and muscle atrophy are common. In the late stages of ALS, paralysis of the muscles occurs. Paralysis means the complete loss of voluntary movements.

ALS doesn’t affect your senses, like seeing or hearing. Bowel and bladder control can be affected in later stages of the disease.

ALS is a terminal illness, which means that it eventually results in loss of life. People typically live with ALS for 2 to 5 years. Some people will live longer. Approximately 20% of people live with ALS for over 5 years, and 10% for more than 10 years. The most common life-ending event in ALS is respiratory failure.

While ALS specifically affects the motor neurons of the brain and spinal cord, other body systems that rely on these neurons will be impacted as the disease progresses. As the ability to control voluntary muscles declines, functions like breathing, speaking, and moving are affected.

ALS progresses differently for everyone. A doctor or neurologist who specializes in the condition can help those with ALS understand what to expect.

ALS complications

ALS can affect many aspects of daily functioning. These include:

Respiratory system and breathing

ALS causes the muscles controlling breathing to weaken over time. Breathing is likely to become more laborious. As the respiratory system weakens, the risk of pneumonia increases. Eventually, as the condition progresses, a ventilator may be required to assist breathing.


Muscles in the mouth, jaw, and throat tend to lose strength and mobility. Because of this, it can become hard for a person with ALS to make themselves understood when speaking. In severe cases, some people lose the ability to produce speech.


ALS usually affects chewing and swallowing, making eating more difficult. Choking is a possible complication.

Weight loss and malnutrition

Because eating can become challenging and ALS may cause people to burn calories more quickly, it’s common to experience rapid weight loss and undernutrition.


Standing and walking will generally become more difficult over time. Some people will have trouble moving their arms.

The changes will happen differently for each person. But in general, more muscles will be affected, and the loss of function will become more severe as ALS progresses. Pressure sores are a possible complication as moving becomes harder.


ALS causes cognitive changes in up to 50% of cases. These changes can affect language and executive function. Dementia is possible but less common. In ALS, physical changes to the brain can also cause uncontrollable laughing and crying, known as emotional lability.

Some variants of ALS are more commonly associated with cognitive changes, like ALS-frontotemporal spectrum disorder.


It’s typical to feel a range of emotions when coping with a serious illness. Managing symptoms and life changes caused by ALS can be emotionally difficult. For some people with ALS, these changes can result in anxiety and depression.

If you’re living with ALS and notice changes in your daily functioning, talk with your doctor and healthcare team. Medication and support can help maintain quality of life, even as symptoms progress.

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Cognitive changes are common among people with ALS, affecting between 30% and 50% of those with the disease. The changes are usually classified as mild to moderate. Difficulty with reasoning, planning, and slowed thinking are among the most common cognitive symptoms of ALS.

Behavioral changes like emotional lability (uncontrollable laughing and crying) are also possible, even if cognition is otherwise unaffected.

It’s less common, but ALS-related dementia can also occur if there’s cell degeneration in the frontotemporal regions of the brain.

ALS is usually diagnosed by a neurologist. There’s no specific test for ALS. The process of establishing a diagnosis can take anywhere from weeks to months.

An ALS diagnosis may be considered if someone has nerve and muscle health concerns that get worse over time. A doctor will watch for increasing symptoms like:

  • muscle weakness
  • muscle atrophy
  • twitching
  • cramps
  • rigid tissue, known as contracture

These symptoms can also be caused by a number of other conditions. Therefore, a diagnosis requires your doctor to rule out other health concerns. This is done with a series of diagnostic tests, including:

  • an EMG test to evaluate the electrical activity of your muscles
  • nerve conduction studies to test your nerve function
  • an MRI scan that shows which parts of your nervous system are affected
  • blood tests to evaluate your general health and nutrition

Genetic tests may also be useful for people with a family history of ALS.

Many different areas of functioning can be affected as control over voluntary movements declines. Treatments and supports are available to address most symptoms.

A team of doctors and specialists often work together to treat people with ALS. Specialists involved in the ALS team might include:

  • a neurologist who is skilled in the management of ALS
  • a doctor who specializes in physical medicine and rehabilitation (physiatrist)
  • a dietitian
  • a gastroenterologist
  • an occupational therapist
  • a respiratory therapist
  • a speech therapist
  • a social worker
  • a psychologist
  • a pastoral care professional
  • a doctor who specializes in palliative care

Family members should talk with people with ALS about their care. As the condition progresses, some people may need support when making medical decisions.

Connecting with a local ALS society can help people with ALS and their families access resources and support.

Assistive devices

Assistive devices like braces, mattresses, and wheelchairs can reduce pain by supporting the body in a more comfortable position.

Some people may need nutritional support, like a feeding tube (enteral feeding).

As speech becomes more difficult, communication tools provide another way to express thoughts and needs. Options include communication boards and electronic assistive communication devices.

If you’re considering assistive devices, it’s best to consult with your healthcare team to find the right options for you.


Two medications — riluzole (Rilutek, Tiglutik, Exservan) and edaravone (Radicava) — are approved for the treatment of ALS.

Riluzole appears to reduce a particular kind of nerve damage called glutamate-induced excitotoxicity. It can slow the progression of respiratory symptoms and prolong life by several months.

Edaravone (Radicava) appears to help with ALS symptoms by reducing oxidative stress. It can slow the progression of ALS, especially for those in the early stages of the condition.

Other medications may be used to treat the symptoms of ALS. Some of these medications include:

As of 2020, more than 40 potential new medications for ALS are being studied. Clinical trials for stem cell therapy are also underway. But stem cell therapy hasn’t yet been proven to be an effective treatment for ALS.

Nonmedical treatments

Your doctor may recommend therapies like heat treatments, exercise, and physical therapy to reduce ALS symptoms. These should only be undertaken as directed by your healthcare team.

Massage, meditation, and other complementary and alternative therapies may also help with relaxation and comfort. Before starting any nonmedical treatment, it’s important to discuss it with your doctor.

There’s currently no cure for ALS. But medication and supportive care can improve quality of life. Make it a priority to discuss new or changing symptoms with your healthcare team. Proper treatment and support can help those with ALS live happily and comfortably for as long as possible.