Axonal damage in multiple sclerosis patients with high versus low expanded disability status scale score

Background: The pathophysiological basis for differences in disability in patients with multiple sclerosis is unclear. Methods: We used magnetic resonance imaging to examine whether differences in disability in cohorts of multiple sclerosis patients with similar T2-weighted lesion volume and disease duration were associated with a more destructive disease process in the more disabled patients. Results: The benign and severely disabled groups had similar brain atrophy metrics and similar decreases of the neuronal marker, N-acetylaspartate, in the normal appearing white matter of the cerebrum on magnetic resonance spectroscopy examination in vivo. The severely disabled cohort had more spinal cord atrophy. Conclusion: The dissociation of spinal cord atrophy and cerebral atrophy between these two groups suggests that the difference between the more benign and more disabled groups cannot be explained by a more aggressive pathological process that is affecting the entire neuroaxis in a homogeneous fashion.