title: Short interval intracortical facilitation correlates with the degree of disability in multiple sclerosis.
abstract: BACKGROUND
  The Expanded Disability Status Scale (EDSS) is the most widely used measure of disability in MS, however because of its limitations surrogate markers of clinical disability progression are of high interest. Transcranial magnetic stimulation (TMS) measures of demyelination and cortical excitability correlate with disability levels in MS.
  
  
  OBJECTIVE
  Aim of this study was testing whether paired pulse (pp) TMS represents a reliable surrogate marker to measure clinical disability in MS.
  
  
  METHODS
  ppTMS measures of intracortical synaptic transmission such as short interval intracortical inhibition (SICI), long interval intracortical inhibition (LICI), short interval intracortical facilitation (SICF) and intracortical facilitation (ICF) were collected from 74 patients affected by MS. Correlation of EDSS scores with ppTMS measures was analyzed.
  
  
  RESULTS
  EDSS scores correlated with patient's age, disease duration, Motor Evoked Potentials latency and thresholds and SICF measures but not with age of onset, SICI, ICF and LICI.
  
  
  CONCLUSIONS
  These findings support a possible use of SICF and MEP latency as surrogate markers of disability in MS. Further research is warranted to determine the role of SICF in the follow up of disease progression and to validate its use as an endpoint in multiple sclerosis clinical trials.
authors.affiliation: Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, 00133 Rome, Italy. francesco808@virgilio.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Mori
authors.forename: Hajime
authors.initials: H
authors.lastname: Kusayanagi
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Monteleone
authors.forename: Alessandro
authors.initials: A
authors.lastname: Moscatelli
authors.forename: Carolina G
authors.initials: CG
authors.lastname: Nicoletti
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bernardi
authors.forename: Diego
authors.initials: D
authors.lastname: Centonze
mesh_terms: D004185:Disability Evaluation; D019054:Evoked Potentials, Motor / Q000502:physiology*; D006801:Humans; D009103:Multiple Sclerosis / Q000150:complications* / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation