Amyotrophic lateral sclerosis (ALS) and Parkinson’s disease both affect the brain and nervous system and worsen over time. However, they have key differences that are vital to recognizing the conditions and understanding treatment.

While ALS and Parkinson’s disease affect movement, causing tremors at an early stage before progressing to more severe symptoms, both conditions damage different areas of the nervous system and require different treatments.

People with Parkinson’s disease often live for much longer than those with ALS, but both can lead to severe disability. The difference is ALS always leads to disability, whereas Parkinson’s disease may not lead to severe disability.

This article explains the differences and similarities between Parkinson’s disease and ALS.

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ALS, or Lou Gehrig’s disease, is a condition that attacks and weakens a type of nerve cell called motor neurons. These control muscle movement and breathing. ALS breaks down and destroys motor neurons, which stop communicating with muscles. Over time, the muscles become weak, start twitching, and lose mass.

People develop the condition at an average of 55 years of age, according to the ALS Association. However, ALS can develop between 20 and 30 years of age for some people. It is rare, affecting around 31,000 people in the United States as of 2017.

ALS progresses to the stage where a person cannot walk, talk, or chew food. It is often fatal within 3–5 years due to its effects on breathing, but around 1 in 10 people with ALS live for 10 or more years.

Learn more about ALS.

Parkinson’s disease is a different brain disorder that causes shaking and other movements that are difficult to control. It targets and destroys the cells in the basal ganglia, which is a part of the brain responsible for movement.

Parkinson’s disease is the second-leading condition that destroys the nerve cells over time after Alzheimer’s disease, developing in 500,000 people in the United States.

The nerves in the basal ganglia usually produce a neurotransmitter called dopamine, but they may produce less in people with Parkinson’s disease. This has a role to play in the movement issues that Parkinson’s disease can cause.

Parkinson’s disease also destroys the nerve endings that produce norepinephrine, a neurotransmitter that sends signals through the system, driving unconscious processes such as how the heart beats and blood pressure control.

Parkinson’s disease causes severely disabling symptoms as it progresses. However, it is not a direct cause of death, and people with Parkinson’s disease may have a typical life expectancy due to modern treatments.

Learn more about Parkinson’s disease.

The symptoms of ALS and Parkinson’s worsen over time and affect the muscles. However, important differences can support getting an earlier diagnosis.

ALS symptoms

ALS causes different early symptoms depending on which type of ALS a person has. Limb onset ALS starts with symptoms that affect the limbs, while bulbar onset ALS affects chewing and swallowing muscles.

Early ALS symptoms include:

  • muscle stiffness, cramps, and twitching
  • muscle loss
  • weakness in the limbs or neck
  • slurred speech
  • speech with a nasal quality
  • difficulties chewing or swallowing food

These symptoms progress to the following:

  • excessive drooling
  • issues with speech
  • breathing difficulties
  • pseudobulbar symptoms, which involve uncontrolled and out-of-context crying or laughter
  • constipation
  • unwanted weight loss
  • nutritional problems
  • severe disability around walking, using the arms and hands, and breathing independently

Read about the stages of ALS.

Parkinson’s disease symptoms

Parkinson’s disease symptoms progress differently depending on the individual.

They generally progress slowly and gradually, and loved ones may first notice symptoms such as reduced facial expressions or changes in body movements. The symptoms typically begin on one side of the body and usually remain worse on that side when the effects of Parkinson’s disease start to affect both sides.

The four main symptoms of Parkinson’s disease include:

  • hand, arm, leg, jaw, or head shaking
  • stiffness in the muscles
  • slow movements
  • balance and coordination issues that cause regular falls

Other symptoms might include:

  • emotional changes, including depression
  • swallowing, chewing, and speech impairments
  • difficulties passing urine or stools
  • sleep issues, such as insomnia
  • changes in handwriting, typically involving a switch to cramped, small letters
  • a “Parkinsonian gait” that includes more leaning forward, small, quick steps, and less arm-swinging while walking
  • problems with memory and thinking, sometimes progressing to Parkinson’s dementia

Learn about the early signs of Parkinson’s disease.

The table below compares the symptoms of the two conditions.

ALSParkinson’s disease
muscle stiffness, cramps, and twitchinguncontrollable hand, arm, leg, jaw, or head shaking
muscle lossmuscle stiffness
weakness in the limbs or neckslow movements
nasal or slurred speechbalance and coordination issues leading to regular falls
problems with chewing or swallowing foodswallowing, chewing, and speech impairments
excessive droolingemotional changes, including depression
breathing difficultiesdifficulties passing urine or stools
pseudobulbar symptomssleep issues
constipationchanges in handwriting, typically involving cramped, small letters
unwanted weight loss and nutritional problemsParkinsonian gait
severe disabilitycognition problems and Parkinson’s dementia

ALS and Parkinson’s disease both occur due to the breakdown of different areas of the nervous system. The direct causes of both conditions are not clear, but certain factors contribute to the risk of developing each.


The following are risk factors for developing ALS:

  • being between 55 and 75 years of age, although ALS can develop at any age
  • being male, although older adults of both sexes have equal risk
  • having exposure to pesticides, lead, and environmental toxins, sometimes through the military
  • having some genes with links to ALS

Parkinson’s disease

Risk factors for Parkinson’s disease include:

  • being over 60 years of age, although it can develop before 50 years
  • biological parents with Parkinson’s disease, for some people
  • some changes to specific genes
  • possible exposure to some toxins

Both ALS and Parkinson’s disease require increasing levels of care as a person ages and the conditions progress. No treatment can reverse or cure either condition.

However, different treatments for ALS and Parkinson’s disease can help reduce symptoms, restore some quality of life, and slow the decline in function.


Some medications can help people with ALS manage certain symptoms, including:

  • Riluzole (Rilutek): This may reduce motor neuron damage by lowering levels of a neurotransmitter called glutamate.
  • Edaravone (Radicava): This is an antioxidant that can slow functional decline in some people with ALS.
  • Sodium phenylbutyrate/taurursodiol (Relyvrio): This may prevent nerve cell death by blocking stress signals, which slows functional decline and extends survival for some people.
  • Tofersen (Qualsody): This medication was recently approved to treat ALS in people with specific gene mutations.

Healthcare professionals may prescribe other medications to manage specific symptoms. As the condition worsens, people with ALS may need support for feeding, speaking, mobility, and breathing. These may include wheelchairs, digital speech assistance, feeding tubes, and mechanical ventilators.

Learn more about medications for ALS.

Parkinson’s disease

Medications, surgery, and other therapies can support Parkinson’s disease symptoms:

  • Medications: Drugs can boost dopamine in the brain, boost neurotransmitter levels, and manage symptoms not linked to movement. Levodopa is the main medication for Parkinson’s — people typically take a medication called carbidopa alongside it to reduce side effects and improve the effects on the brain.
  • Surgery: Deep brain stimulation with electrodes may stimulate areas of the brain that support movement in people who do not tolerate medications well.
  • Other therapies: Options such as massage, occupational, speech, and physical therapy may help improve balance, coordination, and flexibility and reduce muscle tension.
  • Lifestyle: A balanced diet and regular exercise, including yoga and tai chi, can support overall health with Parkinson’s disease.

Learn more about treatment options for Parkinson’s disease.

ALS can have some similar symptoms to Parkinson’s disease, especially those that affect muscle movement, chewing, swallowing, and speech. However, ALS affects motor neurons, while Parkinson’s disease affects nerve cells that produce dopamine in the basal ganglia.

This means that ALS causes different muscle symptoms, such as wasting, and may affect different muscles, causing breathing issues. Parkinson’s disease may have more of an effect on gait, balance, and cognition. However, ALS can have a much more significant effect on a person’s life expectancy.

There is no cure for either condition, but medications can help relieve some symptoms and effects on the nerves. Individuals can discuss treatment options with their healthcare professionals.