title: Predictive value of motor evoked potentials in clinically isolated syndrome.
abstract: OBJECTIVE
  To assess the predictive role of several measures obtained by transcranial magnetic stimulation (TMS) in patients with clinically isolated syndrome (CIS) for the risk of conversion to multiple sclerosis (MS) during the first 2 years.
  
  
  METHODS
  We investigated 34 patients with CIS. After 2 years of follow-up and classification into two groups according to MS diagnosis, initial TMS measures were compared to determine their predictive values for conversion to MS.
  
  
  RESULTS
  Sixteen patients developed MS. We observed a significant difference between the two groups for contralateral silent period and no significant difference for the central motor conduction time, amplitude ratio, motor threshold, ipsilateral silent period, and the transcallosal conduction time.
  
  
  CONCLUSIONS
  Contralateral silent period (SP) seems to be a valuable parameter to early distinguish patients who will develop MS or not. This result about SP during CIS has never been described until now. An increased contralateral silent period would predict a conversion to MS with a positive predictive value of 75%, but this result needs to be confirmed in larger groups.
authors.affiliation: Service de Neurologie et de Neurophysiologie Clinique, Hôpital Bretonneau, CHRU Tours, France. maudpallix@aol.com
authors.forename: M
authors.initials: M
authors.lastname: Pallix-Guyot
authors.forename: A-M
authors.initials: AM
authors.lastname: Guennoc
authors.forename: H
authors.initials: H
authors.lastname: Blasco
authors.forename: B
authors.initials: B
authors.lastname: de Toffol
authors.forename: P
authors.initials: P
authors.lastname: Corcia
authors.forename: J
authors.initials: J
authors.lastname: Praline
mesh_terms: D000293:Adolescent; D000328:Adult; D003711:Demyelinating Diseases / Q000503:physiopathology*; D018450:Disease Progression; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult