SPINAL-CORD ATROPHY AND DISABILITY IN MS - A LONGITUDINAL-STUDY

Objective: To assess whether it is possible to measure changes in cord cross-sectional area during a 1-year period in patients with MS relia bly. Background: Involvement of the spinal cord in MS is extremely com mon and an important element in the development of disability. Althoug h little relation has been shown between the cord lesion load and disa bility, a strong correlation between spinal cord atrophy and the expan ded disability status scale (EDSS) has been demonstrated in cross-sect ional studies. Method: A highly reproducible semiautomated technique t hat measures the cross-sectional area of the cord at the C2 level was applied to 13 healthy control subjects and 28 patients serially. Resul ts: This study confirms that patients have significantly smaller cords than control subjects at baseline (control subjects: mean 80.95 mm(2) , patients: mean 71.25 mm(2), p = 0.01) and demonstrates that patients have a significant loss in cord cross-sectional area during 12 months , which was not seen in control subjects (p < 0.001). This reduction i n cord size was most marked in the primary progressive patients who ha d a mean cord cross-sectional area loss of 3.52 mm(2) (5.2%) and least in the secondary progressive (-0.26 mm(2), 0.7%) and benign patients (-0.41 mm(2), 0.8%). The baseline cord cross-sectional area correlated strongly with the EDSS (r = -0.52, p = 0.005) and with disease durati on (r = -0.75, p < 0.001); however, there was no significant differenc e in cord area (p = 0.69) or change in cord area (p = 0.51) between th ose patients with a definite increase in EDSS and those without. Concl usion: This study demonstrates, for the first time, that it is possibl e to measure changes in cord cross-sectional area over time. The seria l measurement of spinal cord atrophy may thus make an important contri bution to the evaluation of therapeutic efficacy, especially in primar y progressive disease.