title: A 3meter Timed Tandem Walk is an early marker of motor and cerebellar impairment in fully ambulatory MS patients.
abstract: BACKGROUND
  Mobility assessment in Multiple Sclerosis (MS) is crucial for trials and individual patient counseling. Up to now, standard tests as the Timed 25-Foot Walk (T25FW) are restricted by floor effects in mildly disabled patients. The 3-meter Timed Tandem Walk (TTW) as a possibly more sensitive measure has not been investigated yet.
  
  
  OBJECTIVE
  To investigate sensitivity and specificity of the TTW and T25FW to detect mild clinical impairment in a large cohort of MS patients.
  
  
  METHODS
  We extracted T25FW, TTW and EDSS from our UMC patient database (2009-2012). After randomization into an explorative (n = 497) and validation (n = 228) cohort, we calculated change rates and performed ROC analyses of gait tests and EDSS including Functional System Scores.
  
  
  RESULTS
  Between disability stages of EDSS 0-2.5 and EDSS 3.0-4.0, the mean TTW difference was 4s (T25FW = 0.9s). The accuracy to separate between EDSS groups was moderate but identical for both tests (ROC-AUC T25FW = 0.79, TTW = 0.80, p = 0.4). TTW had a higher sensitivity and specificity to differentiate between asymptomatic and symptomatic patients concerning FS motor/cerebellar scores (ROC-AUC T25FW = 0.71, TTW = 0.75, p < 0.05). All hypotheses could be validated in the second cohort.
  
  
  CONCLUSIONS
  A 3-m Timed Tandem Walk is a standardized test that is easy to implement to detect impairment of the motor or cerebellar system in fully ambulatory MS patients. Based on the complex-task character, TTW is a potential new outcome measure for MS mobility in mildly disabled patients and can act as easily accessible and significant additional information in patient counseling.
authors.affiliation: Institute for Neuroimmunology and Clinical MS Research (inims) and Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address: j.stellmann@uke.de.
authors.forename: J P
authors.initials: JP
authors.lastname: Stellmann
authors.affiliation: Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Vettorazzi
authors.affiliation: Institute for Neuroimmunology and Clinical MS Research (inims) and Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Poettgen
authors.affiliation: Institute for Neuroimmunology and Clinical MS Research (inims) and Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Heesen
mesh_terms: D000328:Adult; D002526:Cerebellar Diseases / Q000175:diagnosis* / Q000209:etiology*; D015331:Cohort Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications*; D010045:Outpatients; D012372:ROC Curve; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D016138:Walking / Q000502:physiology*
keywords: Mild disability; Mobility; Multiple Sclerosis; Outcome; Timed 25 Foot Walk; Timed Tandem Walk