title: Optimization of mirror therapy to excite ipsilateral primary motor cortex.
abstract: BACKGROUND
  Mirror illusion therapy (mirror therapy) is based on the experimental substrate of a visual illusion of active hand movement to excite ipsilateral primary motor cortex (iM1).
  
  
  OBJECTIVE
  We tested whether iM1 excitability could be modulated by enabling or disabling vision of the active hand during mirror therapy.
  
  
  METHODS
  Motor cortical activations of healthy right-handed participants were identified by magnetoencephalography. Participants performed voluntary index finger extension of their dominant and non-dominant hands, separately, while viewing mirror reflection images of their active hand superimposed upon their hidden inactive hand. This was performed either with vision of the active hand (uncovered viewing condition) or without vision of the active hand (covered viewing condition).
  
  
  RESULTS
  In the covered viewing condition, the iM1could be excited in all participants (n = 10) and this excitation did not differ whether the active hand was the dominant or non-dominant hand. However, in the uncovered viewing condition, dominant and non-dominant hands were able to excite iM1 only in some participants (n = 4 and n = 7, respectively). Moreover, the participants' responses to the illusion validation questionnaire revealed that the covered viewing condition could cause clearer visual illusion for the active hand than the uncovered viewing condition.
  
  
  CONCLUSIONS
  Disabling vision of the active hand during mirror therapy was more effective to excite iM1 responses by creating more immersive visual illusion of the active hand.
authors: Graduate School of Health Sciences, Hiroshima University, Hiroshima, Japan.
authors: Hikmat
authors: H
authors: Hadoush
authors: Hirofumi
authors: H
authors: Mano
authors: Toru
authors: T
authors: Sunagawa
authors: Kazuyoshi
authors: K
authors: Nakanishi
authors: Mitsu
authors: M
authors: Ochi
mesh_terms: D000328:Adult; D001931:Brain Mapping; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005385:Fingers / Q000294:innervation; D007839:Functional Laterality; D006801:Humans; D019018:Imagery, Psychotherapy / Q000379:methods*; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D055815:Young Adult