title: Reduced parietal activation in cervical dystonia after parietal TMS interleaved with fMRI.
abstract: OBJECTIVE
  Clinically normal hand movement with altered cerebral activation patterns in cervical dystonia (CD) may imply cerebral adaptation. Since impaired sensorimotor integration appears to play a role in dystonia, left superior parietal cortex modulation with repetitive transcranial magnetic stimulation (TMS) was employed to further challenge adaptation mechanisms reflected by changes in cerebral activation.
  
  
  METHODS
  Seven CD patients and ten healthy controls were scanned on a 3T magnetic resonance imaging (MRI) scanner with 1 Hz inhibitory interleaved TMS. They executed and imagined right wrist flexion/extension movements. Each task was preceded by a 10-s period with or without TMS.
  
  
  RESULTS
  The activations of both tasks after TMS in controls showed a similar pattern as found in CD without TMS, i.e. activation increases in bilateral prefrontal and posterior parietal regions during both tasks and decreases in right anterior parietal cortex during imagery (P<0.001). the activations of both tasks after TMS in CD were weaker but with a similar trend in activation changes. Only in the right angular gyrus, TMS significantly failed to induce an activation increase in CD as was seen in the controls (P<0.001).
  
  
  CONCLUSIONS
  The similarity between TMS effects on the distribution of cerebral activations in controls and the pattern seen in CD may support the concept that CD make use of compensatory circuitry enabling clinically normal hand movement. The fact that a similar but weaker TMS effect occurred in CD could suggest that the capacity of compensation is reduced. Particularly for the right angular gyrus, this reduction was statistically significant.
authors.affiliation: Department of Neurology, University Medical Center Groningen, University of Groningen, The Netherlands. pm.devries@vumc.nl
authors.forename: Paulien M
authors.initials: PM
authors.lastname: de Vries
authors.forename: Bauke M
authors.initials: BM
authors.lastname: de Jong
authors.forename: Daryl E
authors.initials: DE
authors.lastname: Bohning
authors.forename: Vanessa K
authors.initials: VK
authors.lastname: Hinson
authors.forename: Mark S
authors.initials: MS
authors.lastname: George
authors.forename: Klaus L
authors.initials: KL
authors.lastname: Leenders
mesh_terms: D000328:Adult; D000368:Aged; D003627:Data Interpretation, Statistical; D005260:Female; D007839:Functional Laterality; D006225:Hand; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D010296:Parietal Lobe / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology; D014103:Torticollis / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*