Multiple sclerosis, or MS, is "a chronic, immune-mediated disease that affects the central nervous system," with incidence most common in young adults-approximately 90% of those diagnosed are aged 16 to 60-although MS can appear at any age (Smith & Shapiro 7). Women are more often affected than men ("Definition"). The central nervous system problems that MS causes can result in issues with muscle control, balance, strength, and vision, as well as seemingly non-physiological functions such as feeling and thinking (Erstad). This paper will discuss MS and describe its relative distribution in Canada.
MS destroys myelin, the protective covering of the nerve cells necessary for the brain and spinal cord to communicate with the nerves in the rest of the body (Poore & Rhodes). As MS progresses, it gradually destroys myelin throughout the brain and spinal cord, leaving demyelinated patches called "lesions" that cause muscle weakness and the other symptoms of MS (Poore & Rhodes). The disease can eventually case deterioration of the nerves themselves, a process that is irreversible ("Definition"). The symptoms of MS vary widely depending upon which nerves are affected and how much damage has been done, but people with the most severe cases of MS may lose their ability to walk or speak ("Definition").
The diagnosis of MS is difficult to make due to the fact that in the early stages, the symptoms come and go and sometimes disappear for months before returning ("Definition"). However, the disease generally follows one of four courses:
. Relapsing-remitting, where symptoms come and go off and on for many years
. Secondary progressive, which starts with a relapsing-remitting course and then steadily grows worse
. Primary progressive, where the disease is progressive from the very beginning
. Progressive relapsing, where the symptoms fade and come back but nerv...