Multiple Sclerosis vs. ALS: Similarities and Differences

MS vs. ALS


  1. Amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) are neurodegenerative diseases that impact the central nervous system.
  2. People with MS and ALS may face memory problems and cognitive impairment.
  3. People with MS often experience greater mental impairment than people with ALS. People with ALS typically develop greater physical difficulties.

Amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) are neurodegenerative diseases that impact the central nervous system. Both diseases attack the body’s nerves and muscles. In many ways, these two diseases are very similar. However, key differences determine a lot about treatment and outlook.

What Is ALS?

ALS, also known as Lou Gehrig’s disease, is a progressive and fatal disease. ALS greatly impacts the brain and central nervous system. In a healthy body, motor neurons in the brain send signals throughout the body, telling muscles and body systems how to work. ALS slowly destroys those neurons, preventing them from working correctly. 

Eventually, ALS destroys the neurons completely. When this happens, the brain can no longer give commands to the body, and individuals with late-stage ALS become paralyzed. 

What Is MS?

MS is a central nervous system disorder that impacts the brain and spinal cord. It destroys the protective coating on nerves. This slows the relay of instructions from the brain to the body, making motor functions difficult.

MS is rarely completely debilitating or fatal. Some people with MS will experience mild symptoms for many years of their lives but never become incapacitated because of it. Others, however, may experience a rapid progression of symptoms and quickly be unable to care for themselves.


Both diseases attack and destroy the body, affecting muscle and nerve function. For that reason, they share many of the same symptoms, especially in early stages. Initial symptoms include:

  • muscle weakness and stiffness
  • loss of coordination and muscle control
  • difficulty moving limbs 

However, the symptoms then become quite different. People with MS often experience greater mental impairment than people with ALS. People with ALS typically develop greater physical difficulties. 

Mental Capabilities

People with MS and ALS may face memory problems and cognitive impairment.


People with MS can experience severe mental changes, including mood swings, depression, and an inability to focus or multitask. Flare-ups or remissions may increase mood swings and the ability to focus.


For people with ALS, symptoms remain largely physical. In fact, mental function remains intact even when ALS has claimed most of a person’s physical capabilities.

Autoimmune Disease


MS is an autoimmune disease. Autoimmune diseases occur when the immune system mistakenly attacks normal, healthy parts of the body as if they were foreign and dangerous. In the case of MS, the body mistakes myelin — a protective sheath that coats the outside of the nerves — for an invader and tries to destroy it.


ALS is not an autoimmune disease and its cause is largely unknown. However, according to the Mayo Clinic, some possible causes may be:

  • gene mutation
  • chemical imbalance
  • disorganized immune response

A small number of cases are inherited.


An MRI scan can detect demyelination. Doctors can use MRI results to distinguish between the two conditions.


MS targets and attacks myelin in a process called demyelination. This prevents the nerves from performing as well as they once did.


On the other hand, ALS attacks the nerves first. In ALS, the demyelination process begins later, after the nerves have begun to die.



The outlook isn’t clear with MS. Symptoms of MS may come and go, depending on the type of MS you have. You may experience an attack and then symptoms disappear for days, weeks, even years. The progression of MS differs from person to person. Most people fall in one of these four levels of MS:

Relapsing-remitting MS (RRMS)

RRMS is the most common form. Relapses are followed by full or almost full recovery. There is little or no progression of disease after attacks.
Secondary-progressive MS (SPMS)

This is the second stage of RRMS. Disease begins to progress after attacks or relapses.

Primary-progressive MS (PPMS)

Neurologic function begins to worsen from the very beginning of the disease. Progression varies and levels off from time to time. They have only minor remissions.

Progressive-relapsing MS (PRMS)

Progression of the disease is steady from the beginning. It includes attacks or relapses, but no remission from these. This level is not as common as the other three.

MS is rarely debilitating or fatal.


According to the National Institute of Neurological Disorders and Stroke, eventually all individuals with ALS will become unable to walk, stand, or move about without help. They also may develop great difficulty swallowing and chewing. Ultimately, ALS is fatal. 

ALS commonly starts in the hands, feet, or arms and legs. It then spreads to other parts of the body. It does not affect your thought processes or senses. However, later stages can include dementia. It also does not cause incontinence.



The treatments that are currently approved by the FDA for MS are only effective for those that have a relapsing form. There is a lot of research and effort being put into finding treatments for the progressive forms of the disease. Researchers are also working hard to find a cure.

Lifestyle treatments for MS focus primarily on stress reduction. Chronic stress is believed to worsen the neurologic symptoms and increase the number of brain lesions. Lifestyle treatment includes mindfulness. Mindfulness reduces stress and allows for better coping methods in stressful situations.

Since MS attacks or relapses can come without warning, it is important to be willing to adapt your activities to how you feel on a given day. However, staying as active as possible and continuing to socialize can help.


As with MS, there is not a cure for ALS. Treatments are to slow symptoms and prevent some complications. According to the Mayo Clinic, riluzole (Rilutek) is the only FDA-approved drug to treat ALS. For some, it seems to slow the disease’s progression. However, there are other drugs that can help manage other symptoms like constipation, fatigue, and pain.

Physical, occupational, and speech therapy can help manage and compensate for some effects of ALS. When breathing becomes difficult, you can get devices to assist. Psychological support is also important to help you emotionally.


Though both diseases appear to have much in common during the earliest stages, the progression, treatments, and prognoses for ALS and MS are very different. However, in both cases treatment paves the path toward a healthier, more fulfilling life as long as possible.

People with either condition should talk to their doctor about developing a plan for their condition. Your doctor can also prescribe medication that can help manage symptoms.

You asked, we answered

  • I have initial symptoms of both MS and ALS. What tests or procedures are done to determine diagnosis?
  • MRI is often used to distinguish between MS and ALS. In MS, demyelination of the nerves begins and results in nerve changes. In other words, the loss of myelin coating of the nerve occurs first in MS, then a loss of nerve function. In ALS, nerves are damaged by an unknown cause and then the damaged nerves lose their coating or myelin. So by looking for demyelination using MRI, a doctor can often tell the difference between the two diseases, as signs of demyelination often occur well after symptoms have progressed in ALS. Finally, there is no single definitive test to distinguish between the two, but signs, symptoms, and imaging are often used to come to a conclusion.

    - George Krucik, MD, MBA

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