title: Multiple Sclerosis Severity Scale and whole-brain N-acetylaspartate concentration for patients' assessment.
abstract: BACKGROUND
  The ability to predict the course of multiple sclerosis (MS) is highly desirable but lacking.
  
  
  OBJECTIVE
  To test whether the MS Severity Scale (MSSS) and global neuronal viability, assessed through the quantification of the whole-brain N-acetylaspartate concentration (WBNAA), concur or complement the assessment of individual patients' disease course.
  
  
  METHODS
  The MSSS and average WBNAA loss rate (ΔWBNAA, extrapolated based on one current measurement and the assumption that at disease onset neural sparing was similar to healthy controls, obtained with proton magnetic resonance (MR) spectroscopy and magnetic resonance imaging (MRI)) from 61 patients with MS (18 male and 43 female) with long disease duration (15 years or more) were retrospectively examined. Some 27 patients exhibited a 'benign' disease course, characterized by an Expanded Disability Status Scale score (EDSS) of 3.0 or less, and 34 were 'non-benign': EDSS score higher than 3.0.
  
  
  RESULTS
  The two cohorts were indistinguishable in age and disease duration. Benign patients' EDSS and MSSS (2.1 ± 0.7, 1.15 ± 0.60) were significantly lower than non-benign (4.6 ± 1.0, 3.6 ± 1.2; both p < 10(-4)). Their respective average ΔWBNAA, 0.10 ± 0.16 and 0.11 ± 0.12 mM/year, however, were not significantly different (p > 0.7). While MSSS is both sensitive to (92.6%) and specific for (97.0%) benign MS, ΔWBNAA is only sensitive (92.6%) but not specific (2.9%).
  
  
  CONCLUSIONS
  Since the WBNAA loss rate is similar in both phenotypes, the only difference between them is their clinical classification, characterized by MSSS and EDSS. This may indicate that 'benign' MS probably reflects fortuitous sparing of clinically eloquent brain regions and better utilization of brain plasticity.
authors.affiliation: Department of Radiology, New York University School of Medicine, New York, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Rigotti
authors.forename: A
authors.initials: A
authors.lastname: Gass
authors.forename: L
authors.initials: L
authors.lastname: Achtnichts
authors.forename: M
authors.initials: M
authors.lastname: Inglese
authors.forename: J S
authors.initials: JS
authors.lastname: Babb
authors.forename: Y
authors.initials: Y
authors.lastname: Naegelin
authors.forename: J
authors.initials: J
authors.lastname: Hirsch
authors.forename: M
authors.initials: M
authors.lastname: Amann
authors.forename: L
authors.initials: L
authors.lastname: Kappos
authors.forename: O
authors.initials: O
authors.lastname: Gonen
mesh_terms: D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D015415:Biomarkers / Q000032:analysis*; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000378:metabolism* / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D001224:Aspartic Acid; C000179:N-acetylaspartate