ALS, or amyotrophic lateral sclerosis, is a disorder that causes motor neuron degeneration in the lateral part of the spinal cord on both sides. It is an uncommon, rare condition, with an average of 5,000 people receiving a diagnosis each year.

Only 1.5 to 3 people out of 100,000 develop the condition each year, making it a relatively rare disease. Those statistics apply to both North American and European populations.

People with ALS lose the ability to initiate and control voluntary muscle movement. This leads to difficulty going about daily activities and severe disability eventually.

This article explains how common ALS is, alongside detailing symptoms, causes, treatment, and living with the condition.

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ALS is rare. About 30,000 people in the United States are living with ALS, and doctors diagnose around 5,000 new cases each year.

The condition is more common in men than women, as around 60% of people affected are male.

According to the ALS Association, every 90 minutes, someone receives an ALS diagnosis, and someone dies from the condition.

Learn more about ALS here.

ALS affects the motor neurons in the body. Neurons facilitate communication between the nervous system and the voluntary muscles, such as the biceps in the arm or the hamstrings in the leg.

In people without ALS, the motor neurons in the brainstem or spinal cord, or upper motor neurons, send signals to the muscles via the motor neurons in the spinal nerves and the peripheral nerves, or lower motor neurons.

ALS is one of the only neurological conditions that causes both lower motor neuron and upper motor neuron symptoms.

Nerves that ALC affect include those that control:

  • moving the arms and legs
  • speaking and swallowing
  • supporting the neck and trunk
  • breathing

Some evidence suggests early involvement of the motor regions of the cerebral cortex. Researchers have not determined whether this is a cause or an effect of the ALS disease process.

Learn more about how ALS affects the brain here.

ALS progresses over time. The muscles get gradually weaker and waste away.

Overall symptoms of ALS include:

  • muscle weakness
  • increased muscle tone and stiffness or spasticity
  • increased reflexes or hyperreflexia
  • abnormal speech and swallowing
  • muscle weakness and wasting or atrophy
  • decreased muscle tone
  • decreased reflexes or hyporeflexia
  • twitching of muscle fibers or fasciculations
  • muscle cramps

The condition eventually leads to a person losing the ability to control the muscles in their chest and diaphragm, which signals respiratory system failure.

Besides the motor symptoms, a person may also experience cognitive or mental health symptoms with ALS.

Learn more about the symptoms of ALS here.

It’s important that a person talks with their doctor as soon as possible if they develop any of the above symptoms. A person may easily overlook the first symptoms of ALS because they can be so subtle.

ALS has an average diagnostic delay of 1 year from when a person first experiences symptoms.

The earliest symptoms of the disease to watch out for include:

  • muscle twitches in the arm, leg, shoulder, or tongue
  • muscle cramps
  • tight and stiff muscles
  • muscle weakness affecting an arm, a leg, the neck, or the diaphragm
  • slurred or nasal speech
  • trouble chewing or swallowing

ALS may be sporadic, meaning they occur at random with no family history or historical risks, or familial, which is genetic. Around 10% of ALS cases are familial, with sometimes more than one person in the family having the condition.

Doctors do not know the exact cause of sporadic ALS, but it may relate to damage and death of motor neurons due to:

  • dysfunction of protein balance
  • excessive neuron stimulation or excitotoxicity, which can damage the nervous system
  • oxidative stress
  • neuroinflammation
  • dysfunction of mitochondria, which is the powerhouse of the cell

Sporadic ALS, which is when a person has no family members affected by the condition, accounts for 90% of cases.

Risk factors for developing ALS include a person’s family history and age.

Scientists have identified more than 25 genes linked to the condition, with the most common being the gene C9ORF72.

Familial ALS usually follows a dominant genetic inheritance pattern, which means a person only needs a single copy of a genetic variant to develop the disease. However, some people with one of these genetic variants do not develop the disease at all.

In most cases, people find out they have ALS between the ages of 55 and 75, and they typically live 2–5 years after they develop symptoms. When younger people develop the disease, they tend to live slightly longer.

Scientists have also explored environmental, dietary, and trauma-related causes, but they have not found any conclusive evidence.

Additionally, doctors do not know why, but military veterans more commonly develop ALS than the general public.

The Food and Drug Administration (FDA) has approved disease-modifying therapies that can slow ALS progression to a limited extent. These therapies include riluzole (Rilutek), phenylbutyrate/taurursodiol (Relyvrio), and edaravone (Radicava).

However, it’s important to note that doctors primarily focus on managing symptoms and supporting people with ALS.

For instance, doctors may treat:

  • muscle spasticity and fasciculations, using muscle relaxants, such as baclofen, tizanidine, diazepam, or cannabinoids
  • muscle cramps, using quinine sulfate, levetiracetam, or mexiletine
  • hypersalivation or sialorrhea, and pooling of secretions, using atropine, scopolamine, amitriptyline, glycopyrrolate, botox injections, or oral suction devices
  • altered mood or behavioral symptoms, using antidepressants such as selective serotonin reuptake inhibitors
  • pain, using appropriate medications for the pain type and location

ALS can make daily living challenging. For instance, it can affect:

  • a person’s ability to walk
  • swallowing, increasing the risk of choking
  • communication
  • movement, increasing the risk of falling

Some people may develop pneumonia if food particles or saliva get into their lungs. If food gets stuck in the windpipe, oxygen deprivation (loss of oxygen) occurs, which can lead to brain damage or even death. This is a potential cause of death in ALS.

Over the course of about 3–5 years, a person with ALS tends to gradually lose the ability to stand or walk. Many people also need mechanical breathing support.

However, symptoms may gradually stabilize in a small proportion of people with ALS, who might maintain that condition status for a few months or in rare cases, years.


Physical therapy and nutrition and weight management support can be beneficial for people diagnosed with ALS.

Physical therapy consisting of daily range-of-motion exercises can help maintain the flexibility in affected joints and prevent muscle fixation.

It’s important that people who have difficulty swallowing eat carefully chosen soft foods, and some people may need nutrition support through a gastric feeding tube.

Also, speech therapy will typically benefit most people with ALS.

Some people with ALS may decide to not use mechanical ventilation. If mechanical ventilation is needed but not used, it can negatively impact a person’s outlook, including adversely affecting their quality of life and shortening their survival.

Most people with ALS will eventually need hospice care because the condition is fatal.

Only 1.5 to 3 people in every 100,000 develop ALS yearly, making it a rare condition. ALS causes neuron degeneration in the spinal cord.

A person with ALS eventually loses the ability to walk, swallow, talk, and breathe. There’s currently no cure for ALS, but there are disease-modifying therapies and other supportive therapies that may slow disease progression or prolong survival for some people.