title: Multiple sessions of low-frequency repetitive transcranial magnetic stimulation in focal hand dystonia: clinical and physiological effects.
abstract: OBJECTIVE
  The ability of low-frequency repetitive transcranial magnetic stimulation (rTMS) to enhance intracortical inhibition has motivated its use as a potential therapeutic intervention in focal hand dystonia (FHD). In this preliminary investigation, we assessed the physiologic and behavioral effects of multiple sessions of rTMS in FHD.
  
  
  METHODS
  12 patients with FHD underwent five daily-sessions of 1 Hz rTMS to contralateral dorsal premotor cortex (dPMC). Patients held a pencil and made movements that did not elicit dystonic symptoms during rTMS. We hypothesized that an active but non-dystonic motor state would increase beneficial effects of rTMS. Five additional patients received sham-rTMS protocol. The area under curve (AUC) of the motor evoked potentials and the cortical silent period (CSP) were measured to assess changes in corticospinal excitability and intracortical inhibition, respectively. Behavioral measures included pen force and velocity during handwriting and subjective report.
  
  
  RESULTS
  Multiple-session rTMS strengthened intracortical inhibition causing a prolongation of CSP after 3 days of intervention and pen force was reduced at day 1 and 5, leaving other measures unchanged. 68% of patients self-reported as 'responders' at day 5, and 58% at follow-up. Age predicted responders.
  
  
  CONCLUSIONS
  A strong therapeutic potential of this rTMS paradigm in FHD was not supported but findings warrant further investigation.
authors: Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, MN 55455, USA. tjk@umn.edu
authors: Teresa Jacobson
authors: TJ
authors: Kimberley
authors: Michael R
authors: MR
authors: Borich
authors: Sanjeev
authors: S
authors: Arora
authors: Hartwig R
authors: HR
authors: Siebner
mesh_terms: D000328:Adult; D000368:Aged; D020821:Dystonic Disorders / Q000503:physiopathology* / Q000628:therapy*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006225:Hand / Q000503:physiopathology*; D006236:Handwriting; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology; D050781:Transcranial Magnetic Stimulation / Q000379:methods*