The motor control area of the Cortex is the first to be Myelinated. The initial linkages are between the Visual and Motor Lobes. Myelination of the Nervous System is not complete until the early teen years. We still do not know what factors promote optimum growth or, conversely, retard it. If only the protective covering is diseased, the function of the fibres is impaired, but some impulses can still be transmitted, although not with full strength.
Function is restored when the sheath's condition improves.
Once the Nerve Fibres themselves are replaced by scar tissue, called plaques, nerve impulses can no longer be carried. After this scar is formed, the damage can not be reversed. Consequently, with intense, sudden impairment or with prolonged impairment, function may be permanently lost in those parts of the body, regulated by the damaged Nerve Fibres. The reason why the disease is termed multiple is that almost any portion of the CNS may be involved. With or without this weakness or paralysis, there may be lack of coordination, staggering and tremor, or poor coordination plus tremor of the extremities, and sometimes of the body and head.