Introduction to multiple sclerosis

Introduction to MS

MS populationMultiple sclerosis (MS) affects about 2.5 million people around the world. And because everybody experiences MS differently, there are no hard and fast rules about what life with the condition will mean for you. However, we do know that multiple sclerosis is a neurological disease that damages cells in your central nervous system (CNS), which is made up of your brain and spinal cord.

The CNS is your body’s main control centre. It controls most of the things your body does from your breathing to thinking. The cells in your central nervous system making all of this possible are called neurons (sometimes called nerve cells).

Introduction to MS

Quick facts

Here’s a short summary of what happens to the brain in MS. If you want to know more explore the information below.

  • Multiple sclerosis causes damage in your central nervous system (CNS) and results in signals not moving as fast along your nerves
  • Your central nervous system controls most of the things your body does, so people living with MS can experience a wide range of symptoms
  • Symptoms range from problems with mobility to problems with vision, extreme tiredness and thinking, but these are just a few examples
The role of the immune system

Your immune system normally helps your body to fight bacteria, viruses and other foreign substances that enter your body. It’s not currently known why, but multiple sclerosis causes changes to the immune system. When you have MS, part of your immune system mistakenly turns against your own healthy cells in your CNS.

It’s this abnormal response that damages the fatty coating surrounding your nerve cells – called myelin.

Why does myelin damage cause symptoms?

Normally, this myelin coating helps signals to move quickly along your nerve cells. This clever messaging system is responsible for every move you make, every sensation you feel and every thought you’ve ever had.

However, when myelin is damaged by multiple sclerosis, the signals travelling along your nerve cells slow down – a bit like removing the coating around electrical wires. This damage affects those all-important messages (or nerve impulses) that tell other parts of the body what to do.

And once the myelin around the nerve is completely gone, the signal may become blocked altogether. This means messages between your brain and the rest of your body can become disrupted, and it’s this disruption that eventually leads to the various symptoms of multiple sclerosis. It’s also why MS symptoms can be so unpredictable, because there is no way of knowing which messages will be affected.

Take a look at the diagram below how your nerve signals can be disrupted in MS:

Introduction to MS gif


Areas of the CNS where myelin has been damaged or has disappeared are called lesions or plaques. Depending on the location of the lesion], you may or may not experience symptoms. For example, a lesion in your optic nerve may cause problems with your eyesight, while other lesions may go unnoticed for much longer. These are called silent lesions, and only a special medical imaging technique called magnetic resonance imaging (MRI) can detect them in your central nervous system.

Find out more about MRI scans here.

What are the different symptoms of multiple sclerosis?

Because the CNS controls most things the body does, people living with MS can experience a wide range of symptoms. Try to remember that all people living with MS are different and will experience different symptoms. It is very unlikely that one person will experience all symptoms below.

Some of these physical symptoms are things like:

Introduction to MS - Symptoms

  • Extreme tiredness (fatigue)
  • Numbness and tingling
  • Impaired vision 
  • Unstable walking and balance disorders
  • Muscle weakness and stiffness, tremors
  • Difficulty speaking and swallowing
  • Loss of control over the bladder and bowel
  • Impaired sexual function 

Problems with thinking and memory (sometimes grouped together as cognitive problems) are also common in people living with MS: Some examples also include problems with:

Introduction to cognitive problems

  • Attention
  • Concentration
  • Problem solving
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