Multiple sclerosis (MS) is a disorder in which the body's immune system destroys the protective sheath that covers nerve fibers. This interferes with the communication between your brain and other parts of the body. Nerve impulses are not transmitted as quickly or efficiently, resulting in symptoms such as:

  • Numbness
  • Tingling
  • Vision loss
  • Weakness
  • Unsteadiness
  • Double vision
  • Fatigue
  • Partial or complete paralysis

Symptoms often will improve and relapse with time. In progressive forms of multiple sclerosis, they will gradually worsen.

Depending on the amount of nerve damage and which nerves are affected, symptoms will vary widely from patient to patient. Early diagnosis of MS can be difficult because symptoms often come and go, sometimes staying away for months.

The four types of MS as described by the National Multiple Sclerosis Society are as follows:

  • Relapsing-remitting multiple sclerosis — is characterized by partial or total recovery after attacks. It is the most common form of MS. Eighty-five percent of people with MS experience a relapsing-remitting form of the disease.
     
  • Secondary-progressive multiple sclerosis — is a relapsing-remitting course which becomes steadily progressive. Attacks and partial recoveries may continue to occur. Of the 85 percent who start with relapsing-remitting disease, more than 60 percent will develop secondary-progressive within 10 years.
     
  • Primary-progressive multiple sclerosis — is progressive from the onset; symptoms generally do not subside (remit). Fifteen percent of people with MS are diagnosed with this form of MS. The diagnosis usually needs to be made after a person has been living for a period of time with progressive disability but not acute attacks.
     
  • Progressive-relapsing multiple sclerosis — is a rare form of MS in which people experience steadily worsening disease from the beginning, but with clear attacks of worsening neurologic function along the way. They may or may not experience some recovery following these relapses, but the disease continues to progress without remissions.