In MS, myelin becomes inflamed, swollen and detached from the fibers. Eventually, the detached myelin is destroyed. Sclerosed (hardened) patches of scar tissue form over the fibers. ("Multiple sclerosis" gets its name from these multiple areas of sclerotic tissue.
When nerve impulses reach a damaged area, some impulses are blocked or delayed from traveling to or from your brain. Symptoms vary depending on the location of the lesions in the central nervous system.
Early signs of MS may be subtle. Blurred or double vision is often the first symptom. Other early symptoms include localized tingling or numbness, hand or leg weakness, fatigue, dizziness and loss of coordination and balance.
As the disease gradually worsens, muscle spasms, slurred speech, vision loss, problems with bladder, bowel or sexual function and paralysis may develop. Occasionally, mental changes such as forgetfulness or confusion occur.