title: Sensory tricks and brain excitability in cervical dystonia: a transcranial magnetic stimulation study.
abstract: BACKGROUND
  Sensory tricks such as touching the face with fingertips often improve cervical dystonia [CD]. This study is to determine whether sensory tricks modulate motor cortex excitability, assessed by paired-pulse transcranial magnetic stimulation [p-pTMS].
  
  
  METHODS
  Eight patients with rotational CD underwent p-pTMS, at rest and when the sensory trick was applied. To test intracortical inhibition [ICI] and facilitation [ICF], the amplitude ratio between conditioned and unconditioned cortical motor evoked potentials was measured at several interstimulus intervals (ISI 1, 3, 15, and 20 ms) and compared with controls mimicking patients' sensory tricks.
  
  
  RESULTS
  At rest, a significant ICF enhancement was found at ISIs 15 through 20 in patients compared with controls, whereas no significant ICI changes were observed. Sensory tricks significantly reduced the abnormal ICF in patients and did not induce any change in controls.
  
  
  CONCLUSIONS
  In our CD patients, sensory tricks seem to improve dystonia through an inhibitory effect on motor cortex excitability.
authors.affiliation: Department of Neurology, Neurophysiology and Neurorehabilitation-INSPE, Institute of Experimental Neurology, Scientific Institute Ospedale San Raffaele, Via Olgettina 60, Milan, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Amadio
authors.forename: Elise
authors.initials: E
authors.lastname: Houdayer
authors.forename: Francesca
authors.initials: F
authors.lastname: Bianchi
authors.forename: Habtom
authors.initials: H
authors.lastname: Tesfaghebriel Tekle
authors.forename: Ivan Pietro
authors.initials: IP
authors.lastname: Urban
authors.forename: Calogera
authors.initials: C
authors.lastname: Butera
authors.forename: Roberta
authors.initials: R
authors.lastname: Guerriero
authors.forename: Marco
authors.initials: M
authors.lastname: Cursi
authors.forename: Letizia
authors.initials: L
authors.lastname: Leocani
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Comi
authors.forename: Ubaldo
authors.initials: U
authors.lastname: Del Carro
mesh_terms: D000328:Adult; D001905:Botulinum Toxins / Q000627:therapeutic use; D001921:Brain / Q000503:physiopathology*; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology; D009498:Neurotoxins / Q000627:therapeutic use; D014103:Torticollis / Q000188:drug therapy / Q000473:pathology*; D014110:Touch / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation
chemical_list: D009498:Neurotoxins; D001905:Botulinum Toxins
keywords: cervical dystonia; intracortical facilitation; intracortical inhibition; sensory trick; transcranial magnetic stimulation