Multiple Sclerosis: Changes Beyond Demyelination.

Multiple Sclerosis: Changes Beyond Demyelination

Multiple Sclerosis: Changes Beyond Demyelination

Multiple sclerosis (MS) is an autoimmune disease characterized by destruction of the myelin sheath surrounding the axons of the central nervous system. The damaged oligodendrocytes which generate myelin cannot be restored. Scarring occurs, which results in an interruption of the salutatory conduction of an action potential down the axon. This slower conduction velocity results in weakness and lack of coordination in the individual suffering from MS (Bear, Connors, & Paradiso, 2001, p. 94). Previously, MS was thought to only involve white matter. New research however has shed light on the disease, and changes in the central nervous system beyond demyelination may be involved. This paper is a review and discussion of three recent studies in which various MRI techniques were employed to examine changes beyond demyelination in MS patients.

Evanelou, et al. investigated the relationship between axonal losses in normal-appearing areas of the corpus callosum to the lesion volume in corresponding areas of cerebral white matter.

The researchers performed post-mortem brain imaging on eight patients with relapsing-remitting or secondary progressive MS and eight age- and sex-matched control subjects with no neurological conditions. MRI measured three regions of the corpus callosum for axonal density, estimated number of axons crossing corpus callosum and cross-sectional area. These results were compared to the calculated volume of lesions in three corresponding areas of the cerebral hemispheres. Comparisons of results between MS and control were performed with the Wilcoxon signed ranked test and the one-tailed Pearson correlations. Relationships between the axonal and cerebral measures were applied by multiple regression analysis. A significant difference was found between groups only in the total number of axons crossing the corpus callosum in each of the three regions (p

Brain atrophy detected by MRI has recently been proven to be...