title: Monitoring multiple sclerosis by multimodal evoked potentials: Numerically versus ordinally scaled scoring systems.
abstract: OBJECTIVE
  To compare the ability of different evoked potential scores (EPS) to monitor and predict the disease course in multiple sclerosis (MS).
  
  
  METHODS
  Seventy-two patients with MS or clinically isolated syndrome were investigated by visual, motor, and somatosensory EP and expanded disability status scale (EDSS) at baseline (T0) and months 6, 12, 24, 36 (T4). EP results were rated according to ordinal (o), semi-quantitative (sq), and quantitative (q) EPS. Spearman rank correlation and multivariable linear regression were used to investigate the associations between EPS and clinical disability.
  
  
  RESULTS
  All EPS correlated with EDSS cross-sectionally (0.72⩽rho⩽0.87, all p<0.001) and longitudinally (0.39⩽rho⩽0.47, all p⩽0.004). EPS(T0) and EDSS(T0) together explained 85-86% of EDSS(T4) variance. A posteriori power calculation showed that the sample sizes needed to detect significant changes over 6 months in q-EPS, sq-EPS and o-EPS with 90% certainty would be 50, 129 and 222, respectively. q-EPS change(T1-T0) correlated with EDSS change(T4-T0) (rho=0.56, p<0.001), while sq-EPS and o-EPS changes(T1-T0) did not.
  
  
  CONCLUSIONS
  All three EPS allow disease course monitoring in MS. However, the quantitative EPS detects clinically relevant short-term changes with a smaller sample size than semi-quantitative or ordinal EPS.
  
  
  CONCLUSIONS
  These results underscore the potential of EPS to characterize MS disease evolution.
authors.affiliation: Department of Neurology, University Hospital Basel, Switzerland.
authors.forename: Regina
authors.initials: R
authors.lastname: Schlaeger
authors.affiliation: Department of Neurology, University Hospital Basel, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Hardmeier
authors.affiliation: Department of Neurology, University Hospital Basel, Switzerland.
authors.forename: Marcus
authors.initials: M
authors.lastname: D'Souza
authors.affiliation: Swiss Tropical and Public Health Institute, Switzerland; University of Basel, Switzerland.
authors.forename: Leticia
authors.initials: L
authors.lastname: Grize
authors.affiliation: Swiss Tropical and Public Health Institute, Switzerland; University of Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Schindler
authors.affiliation: Department of Neurology, University Hospital Basel, Switzerland; University of Basel, Switzerland.
authors.forename: Ludwig
authors.initials: L
authors.lastname: Kappos
authors.affiliation: Department of Neurology, University Hospital Basel, Switzerland; University of Basel, Switzerland. Electronic address: peter.fuhr@usb.ch.
authors.forename: Peter
authors.initials: P
authors.lastname: Fuhr
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D018450:Disease Progression; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000503:physiopathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index
keywords: Evoked potentials; Monitoring; Multiple sclerosis; Prognosis