title: Changes in sensory functions after low-frequency repetitive transcranial magnetic stimulation over the motor cortex.
abstract: OBJECTIVE
  To investigate changes in various sensory functions after low-frequency repetitive transcranial magnetic stimulation (rTMS) in healthy subjects.
  
  
  METHODS
  A Neurometer® CPT/C was used to measure current perception threshold (CPT) values at frequencies of 2000, 250, and 5 Hz in the left index finger to assess the tactile sense, fast pain, and slow pain, respectively. Somatosensory evoked potentials (SEPs) elicited by left median nerve stimulation at the wrist were used to assess excitability in the primary sensory cortex (S1). These were investigated before and after rTMS (0.9 Hz, 0.9 ÁEresting motor threshold, 500 pulses) or sham rTMS over the right primary motor cortex (M1).
  
  
  RESULTS
  All CPT values increased significantly and the P25-N33 of SEP amplitude decreased significantly after real rTMS, but not after sham rTMS; however, no correlations between the changes were observed.
  
  
  CONCLUSIONS
  Low-frequency rTMS over the M1 provides global anesthetic effects and inhibits excitability in S1. The lack of correlation between these changes suggests that the anesthetic effects may not always relate to the excitability of S1; thus, the mechanisms responsible for the changes remain unclear. Nevertheless, these findings suggest that rTMS may be a useful strategy for treating intractable pain in rehabilitation medicine.
authors.affiliation: Department of Rehabilitation Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan. rehadell@m.med.u-tokai.ac.jp
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Kodama
authors.forename: Koji
authors.initials: K
authors.lastname: Aono
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Masakado
mesh_terms: D000328:Adult; D000758:Anesthesia; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology; D009044:Motor Cortex / Q000502:physiology*; D012677:Sensation / Q000502:physiology*; D012684:Sensory Thresholds; D050781:Transcranial Magnetic Stimulation; D014953:Wrist / Q000294:innervation