Multiple sclerosis (MS) is a disease that affects a person’s central nervous system. It can limit mobility, which can involve difficulty walking.

According to the National MS Society, around 1 million people in the United States have the disease. Difficulty walking is one of the most common mobility-related symptoms.

This article describes how MS can affect the ability to walk, which tests physical therapists use to gauge mobility, and the range of treatments.

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MS affects a person’s central nervous system, which includes the brain, spinal cord, and optic nerves. This system controls how a person moves and reacts to stimulation, and damage to it can cause problems with mobility.

In a person with MS, a problem with the immune system causes it to attack healthy tissue, in this case, myelin.

Myelin is a fatty substance that surrounds and insulates nerve fibers. It also helps the nerves transmit signals quickly.

If myelin becomes damaged or destroyed, the nerve it was insulating may no longer receive signals correctly. This means that signals passing through the nerve may be interrupted or not pass on at all.

Experts believe that MS-related mobility issues stem from damage to myelin in the cerebellum. The cerebellum is part of the brain that helps with coordination and movement.

These mobility problems may involve:

  • muscle tightness, stiffness, or spasms
  • problems with balance
  • severe numbness in the feet
  • loss of position sense, which involves knowing where the feet are when walking
  • fatigue
  • muscle weakness
  • trouble with vision
  • cognitive issues
  • unstable walking

Gait changes due to MS

A person’s gait is their pattern of walking. Research from 2018 reports that 50⁠–80% of people with MS have balance and gait issues.

Other 2018 research describes the variety of gait changes, such as:

  • a slow walking speed
  • a reduced range of motion in the leg joints
  • a smaller step length
  • reduced stability
  • difficulty lifting the front part of the foot, which is called “foot drop”

Gait issues can increase the risk of falling. The National MS Society reports that 50–70% of people with MS had falls in the 2–6 months before completing the survey.

A physical therapist may ask a person with MS to do a walking test. This involves walking a set distance while the therapist checks their gait.

The findings can help the physical therapist treat gait issues more effectively.

Timed 25-foot walk

This involves walking 25 feet (ft). A person should walk as quickly as is comfortable, and they may use assistive devices, such as a cane.

The person’s physical therapist will time them as they walk to a marker of the distance, and possibly when they walk back again. The goal is to check the speed of the person’s gait, which is a useful measure of walking ability.

Ambulation index

This is similar to, and has been mostly replaced by, the timed 25-ft walk test.

The ambulation index also involves walking 25 ft as quickly as is safe while being timed. The difference is that the goal is to assess mobility, rather than gait speed.

A person receives a score from 0 to 10. A score of 0 indicates that they are fully active, while 10 indicates that they are unable to get out of bed.

Dynamic gait index

This involves checking how a person walks, as well as their balance and risk of falling.

To take this test, a person walks and does other things, such as:

  • changing speed
  • turning their head left and right or up and down
  • avoiding obstacles
  • turning on the spot
  • climbing stairs

The 12-item MS walking scale

Also known as the MSWS-12, this is a questionnaire with 12 statements about how MS is affecting the ability to walk.

The healthcare professional performing the test will ask the person to rate each statement on a scale from 1 to 5.

An answer of “1” means that the person has not experienced what the statement is describing. An answer of “5” means that they have experienced it to a severe extent.

Timed up-and-go test

Physical therapists use this to time how long it takes a person to get up from a chair, walk 10 ft, then return to the chair.

The Centers for Disease Control and Prevention (CDC) explain that if a person takes more than 12 seconds to do this, they have a risk of falling.

As the National MS Society observes, physical therapy can help improve many gait problems.

A person’s physical therapist may recommend vestibular exercises, which induce imbalance, to help a person adapt. These exercises can include:

  • head or eye movements
  • altering visual input
  • walking on different kinds of surfaces

They may also encourage a person to do stretching exercises to improve:

  • flexibility
  • strength
  • cardiovascular fitness
  • balance
  • coordination
  • relaxation

Some prescription medications can also help improve a person’s gait by easing muscle stiffness and increasing walking speed.

Many assistive devices, such as canes, crutches, or braces, can be beneficial for people with MS.

Anyone with trouble walking should speak with healthcare professionals about ways to reduce the risk of falling. This might involve:

  • not wearing high heels
  • avoiding slippery surfaces
  • removing obstacles and trip hazards from the home
  • keeping walking areas well lit, especially at night

MS is can prevent the nerves from passing on electrical signals as they should. This can cause problems with mobility, including trouble walking.

Physical therapists use various tests to check how MS is affecting a person’s gait and improve the approach to treatment.

Stretching and performing exercises, using assistive devices, and possibly taking medications can help ease problems with mobility. Anyone with MS who has difficulty walking should contact a member of their healthcare team.