Multiple Sclerosis Fast Facts

MS damages fragile nerve cells in the brain and spinal cord.

About 400,000 Americans have multiple sclerosis (MS).

Fewer than 200,000 cases are diagnosed each year in the U.S.

MS strikes women more than twice as often as men.

Most people with MS are diagnosed between the ages of 20 and 50.

MS occurs more often in people with epilepsy than in the general population.

The severity of MS varies from individual to individual. The disease can flare and then subside in unpredictable ways.

United Brain Association

Treatment advances and novel therapies are bringing hope to the more than 2.3 million people worldwide who suffer from MS.

What is Multiple Sclerosis?

Multiple sclerosis (MS) is a neurological disease that affects the transmission of nerve impulses in the brain and from the central nervous system to the rest of the body.

Nerves are like electrical wires wrapped with a protective layer of insulation called myelin. The fatty layer of myelin shields the signals moving from the brain down the spinal cord to the muscles to other parts of the body. MS strips the myelin from nerve cells, scarring multiple areas of the brain. The disease erodes the protective covering around the nerves and blocks the delivery of nerve impulses between the body and brain.

Types of MS

There are four distinct types of MS:

  • Relapsing-Remitting MS. In this form of the disease, symptoms come and go. Between attacks, people often feel better, and the condition stops its steady progression. The disease typically flares up again over time. These relapses are followed by quiet periods of remission that can last months or years. About 80% of people with MS have this type of MS.
  • Secondary Progressive MS.  In this form, symptoms of MS come and go but then worsen over time. Many people start with relapsing-remitting MS and progress to secondary progressive disease. About 60-70% of people with relapsing-remitting MS eventually develop secondary-progressive MS.
  • Primary Progressive. In this type, symptoms gradually become more severe as the disease progresses. The condition comes on slowly and onset and moves steadily with no remissions. Approximately 15-18% percent of people with MS are diagnosed with this form of the disease.
  • Progressive Relapsing. In this type, symptoms gradually worsen and are accompanied by attacks that come and go. Progressive relapsing MS is a rare form of multiple sclerosis that initially appears with constant symptoms. People with progressive relapsing MS also experience clinical attacks marked by more severe symptoms.

Symptoms of MS

Multiple sclerosis causes many different symptoms, which vary in severity from person to person. While some people remain symptom-free most of their lives, others suffer severe symptoms that never go away.

Symptoms of MS include:

  • Numbness and tingling
  • Depression
  • Fatigue
  • Impaired coordination
  • Muscle weakness or spasms
  • Pain (headache, back pain, spasms, neuralgia)
  • Itching sensations
  • Sensitivity to heat
  • Cognitive or memory issues (rarely, dementia)
  • Vision problems, eye pain, eye movement abnormalities, and blindness
  • Feeling dizzy or off-balance
  • Walking and gait disturbances
  • Trouble speaking
  • Bowel and bladder problems
  • Sexual dysfunction
  • Permanent nerve damage
  • Paralysis

What Causes Multiple Sclerosis?

The cause of MS remains unknown. Researchers suspect that genetic susceptibility, abnormalities in the immune system, and environmental factors combine to cause MS. Some think a childhood virus may trigger the disease later in life.

Many experts think an overactive immune system sparks MS. Autoimmune disorders strike when the body’s infection-fighting system goes awry and damages healthy tissues. Inflammation defends the body against acute injury or infection, but the system must turn on at just the right moment to repel an assault and then quickly switch off when the threat is over.

Within the nervous system, the immune response may kindle inflammation that destroys the myelin sheath. As the faulty immune system battles a non-existent threat, the body’s disease-fighting defenses unleash a cascade of destructive chemicals.

Additional factors associated with an increased risk of developing MS include:

  • Exposure to the Epstein-Barr virus
  • Low levels of vitamin D
  • Smoking

Is Multiple Sclerosis Hereditary?

While MS tends to run in families, a definite genetic cause has not yet been identified. The risk of developing the disorder is higher for siblings or children of someone with MS than for the general population.

The human leukocyte antigen (HLA) DRB1*1501 has been consistently associated with multiple sclerosis in nearly every population studied. Changes in the HLA-DRB1 gene are the most decisive genetic risk factors for MS,  although exactly how those changes increase the risk of developing MS is not yet fully understood.

How Is Multiple Sclerosis Detected?

Symptoms of MS often appear as early as 10 to 15 years before diagnosis. Some people spend a decade or more seeking an explanation for their frequent falls, fatigue, muscle weakness, tingling sensations, balance issues, and cognitive problems before MS is identified as the cause.

Many secondary problems often worsen as the disease progresses. These symptoms include:

  • Fatigue
  • Depression
  • Infections
  • Limited mobility
  • Anemia
  • Sleep disturbances
  • Foggy memory
  • Sensations of weakness and dizziness

According to guidelines from the American Academy of Neurology, most people should start taking medications as soon as symptoms appear. Early treatment can prevent the development of new lesions in the brain. The sooner treatment begins, the less disability will develop.

How Is Multiple Sclerosis Diagnosed?

No single laboratory test can diagnose or rule out MS. When someone experiences muscle spasms, numbness, lack of coordination, unsteady gait, and other subtle neurological problems, doctors run a battery of tests, including:

  • Blood tests to help rule out other diseases with symptoms similar to those of MS.
  • A lumbar puncture (spinal tap) takes a small sample of cerebrospinal fluid from the spinal canal for laboratory analysis.
  • Magnetic Resonance Imaging (MRI) examines damage to the brain and spinal cord. The non-invasive imaging test shows where nerve damage has occurred. An MRI scan can reveal lesions or scars in the central nervous system where the myelin has been destroyed.


How Is Multiple Sclerosis Treated?

There is no cure for MS. Several FDA-approved “disease-modifying” drugs relieve symptoms. Most MS treatments are delivered as injections or as monthly intravenous (IV) infusions, although new pills are coming onto the market. People frequently switch to a new drug when a particular disease-modifying drug stops working.

Although immune-system suppressing treatments are effective against MS, they disrupt the entire immune system, including its ability to defend against infection. In people with a weakened immune system, a common virus — JCV — can become reactivated in the body. People with antibodies to the virus are at risk for a potentially fatal brain inflammation called progressive multifocal leukoencephalopathy (PML).


Doctors recommend beginning treatment with an FDA-approved disease-modifying therapy as soon as possible following a diagnosis of relapsing or primary progressive MS. Some medications for MS relieve symptoms or treat specific problems, while other drugs affect the disease’s long-term course. Medicines that suppress the immune system relieve symptoms and slow disease progression.

Infusion treatments can help individuals with progressive MS who demonstrate clinical relapses and/or inflammatory activity.

Treatment medications include:

  • Injectable medications. Interferon-beta (Avonex, Betaseron, Extavia, Rebif) was the first FDA-approved medication for MS.
  • Oral medications. The medications available in pill form include teriflunomide (inhibits the function of specific immune cells), fingolimod (reduces the frequency of clinical relapses and delays physical disability), and dimethyl fumarate (thought to inhibit immune cells and molecules).
  • Infused medications. Therapies are delivered through plastic tubing to a small needle into a vein in your arm. Infusions include alemtuzumab, mitoxantrone, ocrelizumab, and natalizumab.


People with MS benefit from a wide range of rehabilitative therapies:

  • Physical Therapy (PT) helps with walking, strength, balance, posture, fatigue, and pain. PT often includes stretching and strengthening exercises for mobility. Therapists also help people with MS learn to use assistive devices, such as wheelchairs and scooters.
  • Occupational Therapy (OT) improves independence and safety at home and work. OT helps people with MS stay relatively active.
  • Speech Therapy. MS can cause problems with the control of the muscles needed for talking and swallowing. A speech and language therapist helps people communicate as clearly as possible. The therapist can provide exercises to improve swallowing.

Managing Relapses

Relapses — also called attacks or exacerbations — are caused by inflammation in the central nervous system. Relapses may involve loss of vision, severe weakness, or poor balance, which interfere with mobility, and overall ability to function.

Although relapse may gradually resolve without treatment, most neurologists recommend treatment with corticosteroids (methylprednisolone, prednisone, and ACTH are the most common). The treatment regimen is usually a three-to-five-day high-dose course, intravenous corticosteroids to reduce inflammation and end the relapse more quickly.

MS in Pregnancy

MS affects women of childbearing age more often than any other group. Doctors suggest treating MS with safer medications during pregnancy since several MS drugs have been shown to cause birth defects. It can take six to 12 weeks for immune-suppressing medications to be cleared from the body. Women with MS who plan to become pregnant should talk to their doctors in advance. A woman who suffers an attack while pregnant can safely take short-term steroids.

After childbirth, MS relapses tend to occur during the first three to six months. The risk of relapse in the postpartum period is estimated to be 20-40%. These relapses do not appear to contribute to increased long-term disability.

How Does Multiple Sclerosis Progress?

Scientists continue to study the complex brain changes that cause MS. On average, people with MS have only a slightly shorter lifespan than the general population. Many people may have long periods of symptom-free living, with occasional flares or exacerbations.

Lesions in the spinal cord and the brain develop as the disease progresses. Gradual worsening, sometimes with acute attacks of inflammation, may occur quickly or slowly. The typical pattern is recurrent episodes followed by partial recovery, although chronic progressive MS also occurs.

There is no way to predict how someone’s disease will progress. Despite difficult challenges, most people with MS live long and productive lives.

How Is Multiple Sclerosis Prevented?

Because the disease’s cause has not yet been determined, there is no known way to prevent MS. In the absence of a sure way to prevent the disease, it’s best to avoid the risk factors that have been positively linked to MS.

  • Take supplements to maintain adequate vitamin D levels in the body. Researchers are studying whether vitamin D can prevent MS. A large Finnish study showed that children of women who were vitamin D deficient early in their pregnancy had a 90% increased risk of developing MS as an adult.
  • Quit smoking. Studies have shown that smoking can substantially increase the risk of developing MS.
  • Lose weight. Obesity increases the chances of developing MS.
  • Exercise slows the progression of MS. Promising early results suggest resistance training may also slow MS progression.
  • Omega-3 oils appear to reduce disease activity and progression. No one knows if they can stave off the disease.

Multiple Sclerosis Caregiver Tips

The most important thing you can do for a loved one with MS is to be supportive. Try these helpful strategies:

  • Get an accurate diagnosis. The early signs of MS can be subtle, making the disease very difficult to detect. Be watchful for MS’s warning signs and bring them to your doctor’s attention whenever you have a concern.
  • Put a treatment plan in place. Be ready to switch medications. MS progresses differently in different individuals, and a treatment that works for one patient might not work for another. Don’t expect your loved one’s treatment plan to go as planned without modifications.
  • Be patient when communicating with someone with MS. Halting or slurred speech can make it challenging to understand what’s being said. Manage your frustration and focus on making your loved one feel comfortable and safe.

Many people with MS also suffer from other brain-related issues, a condition called co-morbidity. Here are a few of the disorders commonly associated with MS:

Multiple Sclerosis Brain Science

MS causes gradual destruction of myelin throughout the brain and spinal cord. As the myelin sheath degenerates, MS affects the nerve cells (neurons) in the brain and spinal cord that control the body and mind.

MRI studies reveal significant lesions in the brain and spinal cord in people with MS. Over time, new lesions develop. An early MRI of the brain may appear normal, but abnormalities occur over time. Lesions are evidence of nerve cell damage in the brain or spinal cord.

Depending on where they occur, the effects of lesions vary:

  • Lesions on the spinal cord cause sensory or motor challenges.
  • Lesions in the front of the brain cause weakness or numbness.
  • Lesions on the back part of the brain cause issues with balance and coordination.

Brain scientists have several promising vaccines in the pipeline. One study showed that people with early signs of MS who were administered a vaccine to prevent tuberculosis (BCG) were less likely to develop full-blown MS than those given a sugar pill. Exactly how BCG vaccination helps prevent MS relapses is unknown. Although research is still early, some scientists believe that regular doses of a vaccine may someday become a routine preventive treatment.

Multiple Sclerosis Research

Title: Low Load Resistance Training Using Blood Flow Restriction for People With Multiple Sclerosis (BFR-MS)

Stage: Recruiting

Contact: Mark M Manago, PT, DPT, PhD 

University of Colorado

Aurora, CO

The Primary Aim of this research study is to determine the feasibility of 8 weeks of physical therapy strengthening exercises using blood flow restriction (BFR) in people with multiple sclerosis (MS) who have moderate-to-severe walking problems. BFR training involves placing a cuff on the leg being exercised to restrict blood flow. The cuff is attached to a specialized device that automatically detects the appropriate amount of pressure to place on the limb. Testing will occur before and after the 8-week treatment period.

Title: Feasibility of a High-intensity Interval Training Program in Persons With Multiple Sclerosis Who Have Walking Disability

Stage: Recruiting

Contact: Elizabeth A Hubbard, PhD 

Berry College

Mount Berry, GA

There is considerable evidence to support the efficacy of moderate-intensity continuous (MIC) exercise benefitting clinically-relevant outcomes in persons with multiple sclerosis (MS). However, persons with MS who have walking impairments (pwMS-wd) are severely deconditioned and may achieve superior benefits by engaging in high-intensity interval training (HIIT), especially while utilizing adaptive equipment, such as with recumbent arm/leg stepping (RSTEP). Of the published studies on HIIT in MS, HIIT yielded significant improvements in cardiorespiratory fitness in all but one study. In those studies that directly compared HIIT to MIC exercise, the data indicated a potential superiority of HIIT compared to MIC in improving physiological conditioning in a time-efficient manner. However, this evidence is specific to those with MS with mild to moderate disability engaging in cycle/arm ergometry, and an investigation of HIIT in pwMS-wd is needed as the feasibility and potential benefits of engaging in HIIT in pwMS-wd is relatively unknown.

The primary aim of the proposed study is to assess the feasibility of a 12-week RSTEP HIIT program in pwMS-wd. The secondary objective is to examine changes in aerobic fitness, physical activity, ambulation, upper arm function, cognition, fatigue, and depressive symptoms as clinically-relevant efficacy outcomes following the 12-week RSTEP HIIT intervention. It is hypothesized that the intervention will be feasible and lead to positive changes in aerobic fitness, physical activity, ambulation, upper arm function, cognition, fatigue, and depressive symptoms. This work is informed by recently published data, which indicate that a single bout of RSTEP HIIT taxes the cardiorespiratory system significantly more than MIC exercise, yet without untoward effects on walking, gait, cognition, mood, or enjoyment. These data suggest that RSTEP HIIT may be an acceptable, safe, and tolerable stimulus for chronic exercise training.  

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