Multiple sclerosis (MS)

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Multiple sclerosis (MS)
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Definition

Multiple sclerosis (MS) is a chronic autoimmune disorder affecting movement, sensation, and bodily functions. It is caused by destruction of the myelin insulation covering nerve fibers (neurons) in the central nervous system (brain and spinal cord).

A newer neuroimaging technique, magnetic resonance spectroscopy (MRS), has been useful in following NAA (N-acetyl-aspartate) levels in patients with multiple sclerosis. NAA is an amino acid found in neurons and axons of the mature brain. In patients with relapsing-remitting MS, NAA levels are reduced, suggesting axonal loss; however, in patients with secondary progressive MS with more disability, the NAA levels are reduced more significantly. In fact, patients with MS had lower levels of NAA even in areas of the brain previously thought to be unaffected, when compared with levels in normal persons.