MS vs. ALS: What Are the Differences?

ALS and multiple sclerosis share some symptoms, but they are distinct diseases

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Multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) are lifelong neurological diseases associated with muscle weakness and physical disability. MS is related to an immune system attack on nerve coverings. ALS weakens muscles and its cause is unknown.

MS and ALS share some similar symptoms. Neither condition is curable, but MS is not life-threatening and may not impact life expectancy. ALS (also known as Lou Gehrig's disease), on the other hand, requires major life-sustaining interventions and is eventually fatal.

This article looks at symptoms, causes, diagnosis, and treatment options in MS vs. ALS.

Symptoms of MS vs. ALS

Neurological symptoms are the hallmark of both MS and ALS. Still, while there are a few overlaps in symptoms, there are major differences.

Common symptoms of ALS and MS.
Ellen Lindner / Verywell 

Muscle weakness or trouble speaking (dysarthria) or swallowing (dysphagia) are among the first symptoms of ALS. In contrast, the first symptoms of MS are often paresthesias (numbness or tingling in extremities) or vision changes.

Either of these conditions can begin with mild problems, such as twitching of the hand, or a major event, such as leg weakness and a sudden fall.

ALS is characterized by a steady decline and worsening symptoms. Some types of MS are characterized by a gradual decline, while others are characterized by periods of remission (improvement) and exacerbations (relapses).

Symptom ALS MS
Muscle weakness (arms and legs) Yes Yes
Paralysis Yes Rare
Trouble speaking Yes Yes (less severe)
Cognitive issues Yes (less common) Yes
Mood changes Yes (less common) Yes
Swallowing problems Yes Yes (less severe)
Breathing problems Yes Rare
Vision changes No Yes
Sensory issues Rare Yes
Bladder/bowel issues Yes Yes

Muscle Weakness in Arms and Legs

ALS always advances to cause muscle paralysis (complete weakness). The muscles eventually atrophy (shrink and deteriorate). Eventually, everyone who has ALS will need an assistive device, such as a walker, wheelchair, or scooter.

Many people with MS experience mild or moderate muscle weakness, but only rarely experience paralysis. MS can affect your walking, and you may need an assistive device to get around, but most people with MS have more independence than those with ALS.

Trouble Speaking

Dysarthria is common in ALS and MS. Dysarthria does not affect your understanding of words because it is not a language disorder. Your speech may be hard to understand, and you might also drool, especially when speaking.

Generally, dysarthria is more severe with ALS than with MS.

Cognitive Issues

MS can produce cognitive dysfunction, which often manifests as clouded thinking or slowed thinking. This can be intermittent or can progress throughout the disease course.

ALS can also have cognitive and behavioral dysfunction that is worse with advancing disease, but not as common when compared to MS patients.

Mood or Personality Changes

MS may produce mood and personality changes due to its direct effect on the brain.

ALS can also be associated with depression, anxiety, and personality changes, but these tend to be less common than in patients with MS.

Swallowing Problems

ALS commonly produces dysphagia. This will often progress to the point that a feeding tube or other means of nutrition is needed.

While MS-related swallowing problems can occur too, they are usually less severe and can typically be managed with swallowing therapy and dietary adjustments.

Breathing Problems

ALS usually causes impaired breathing due to degeneration of the nerves that power the respiratory muscles. Most people with ALS need a device to help with breathing, often starting with noninvasive ventilation (a mask that delivers oxygen). They later progress to mechanical ventilation, which uses a powered machine to support lung function.

Breathing problems rarely occur in MS and are usually mild. Likewise, it is rare for MS-related respiratory problems to require breathing assistance.

Vision Changes

In MS, vision can be affected by optic neuritis or nystagmus. In fact, decreased vision, double vision, and blurred vision are common in MS and often impact driving ability.

ALS does not affect vision, but it can cause altered eye movements late in the course of the disease.

Sensory Symptoms

Sensory changes are common in MS and can manifest with a range of unpleasant sensations, such as numbness and tingling or pain.

Some people with ALS report tingling sensations. However, this is not common and it usually goes away.

Tingling and sensory discomfort are symptoms of MS that are due to the disease itself. In ALS, these symptoms are caused by pressure and prolonged immobility.

Bladder and Bowel Symptoms

It is estimated that over 90% of people who have MS experience bladder dysfunction, including the inability to initiate urination and/or incontinence. People who have ALS can lose motor control and may experience bowel and bladder incontinence.

MS and ALS are both commonly associated with constipation.


Both of these conditions affect the brain and the spine. However, in MS lesions can be seen in the brain and spine by MRI, while in ALS the neuronal damage is not able to be seen on imaging.

MS, but not ALS, can also involve the optic nerves (the nerves that control vision).

MS is three times more common in women, while ALS tends to affect men and women equally.

In addition, the disease pathophysiology (biological changes) of the two conditions is completely different.

Why Do People Develop MS?

MS is a disease caused by demyelination of nerves in the brain, spine, and optic nerves. Myelin is a fatty coating that insulates nerves, allowing them to function efficiently. The nerves don't function as well as they should when they lack adequate myelin, and this results in the symptoms of MS.

Myelin is regularly replaced, and you can recover from an MS relapse without any residual effects. Sometimes, though, nerve damage or scarring can occur, and the neurological deficit can be long lasting or permanent.

It is believed that the demyelination of MS is caused by an autoimmune reaction, in which the body attacks its own myelin. There may be hereditary and environmental components to MS, but the cause remains a mystery.

Why Do People Develop ALS?

With ALS, the motor neurons and tracts located in the brain, brainstem, and spinal cord are gradually damaged, causing muscle weakness and atrophy (shrinkage).

ALS is not believed to have an autoimmune cause, but it isn't clear exactly why the disease occurs.

Diagnosis of MS vs. ALS

A physical examination can show some overlapping features in MS and ALS. For example:

  • Both MS and ALS can cause you to have exaggerated reflexes.
  • You may have decreased motor strength with either condition.
  • Both diseases can affect one or both sides of your body.
  • Your muscle tone can be increased or decreased with either condition.

With MS, you can have altered sensation anywhere on your body (although you might not), but your sensory examination should be normal with ALS.

ALS is often characterized by muscle fasciculations, which look like rapid fluttering of tiny muscles on your tongue, lips, or any other area of the body. With MS, you can have muscle spasms, which are noticeable, involuntary muscle jerks. Spasms may develop late in the course of ALS.

Because of this, testing is needed. You may have some of the same diagnostic tests if you have either of these two conditions, but the results will be completely different.

Testing and Imaging

Diagnostic testing and imaging can help distinguish these two conditions. MS is characterized by abnormalities that can be seen on a brain or spine magnetic resonance imaging (MRI); these are not useful for ALS.

ALS is characterized by alterations in the patterns seen on electromyography (EMG), while MS patients have a normal study.

A lumbar puncture (spinal tap) will show a characteristic pattern with MS that is not seen with ALS.


Both diseases are treated with disease-modifying therapy; other treatments and strategies are used to minimize health complications.

Disease-Modifying Therapy

Disease-modifying therapies (DMTs) are taken on a regular basis to prevent exacerbations and overall neurological decline in MS. Other treatments, including corticosteroids, are used specifically to treat an MS exacerbation.

A disease-modifying therapy for ALS, Radicava (edaravone), was approved by the Food and Drug Administration (FDA) in 2017. This medication is believed to prevent neurotoxic damage, preventing disease progression. The impact on people with ALS is not yet known.

Disease Management

With both of these conditions, support for medical complications and disabilities is a major part of medical care.

For example, you may benefit from physical therapy to optimize your swallowing and motor control. A supportive brace can help you walk or use your hands and arms. Prevention of bed sores, respiratory infections, and malnutrition is important, and strategies related to these issues may be worked into your care over time.

Adapting to bladder and bowel issues may be necessary, and medications used to prevent painful spasms may be helpful.


MS and ALS are both neurological diseases and share some similar symptoms. They also have some distinct differences. One very significant difference is the prognosis: MS is rarely fatal, while ALS is a terminal illness.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. ALS Association. Living with ALS: Resource guide.

  3. National Institute of Neurological Disorders and Stroke. Motor Neuron Diseases Fact Sheet. Last edited August 13, 2019.

  4. ALS Association. Symptoms and diagnosis.

  5. Multiple Sclerosis Association of America. MS symptom listing.

  6. Multiple Sclerosis Association of America. Types of multiple sclerosis.

  7. National Institute on Neurological Disorders and Stroke. Amyotrophic lateral sclerosis.

  8. Aharony SM, Lam O, Corcos J. Evaluation of lower urinary tract symptoms in multiple sclerosis patients: Review of the literature and current guidelines. Can Urol Assoc J. 2017 Jan-Feb;11(1-2):61-64. doi:10.5489/cuaj.4058

  9. National Multiple Sclerosis Society. Who gets MS?

  10. Cruz MP. Edaravone (Radicava): A Novel Neuroprotective Agent for the Treatment of Amyotrophic Lateral Sclerosis. P T. 2018;43(1):25-28.

Additional Reading

By Julie Stachowiak, PhD
Julie Stachowiak, PhD, is the author of the Multiple Sclerosis Manifesto, the winner of the 2009 ForeWord Book of the Year Award, Health Category.