title: Upper extremity rehabilitation of stroke: facilitation of corticospinal excitability using virtual mirror paradigm.
abstract: BACKGROUND
  Several experimental studies in stroke patients suggest that mirror therapy and various virtual reality programs facilitate motor rehabilitation. However, the underlying mechanisms for these therapeutic effects have not been previously described.
  
  
  OBJECTIVE
  We attempted to delineate the changes in corticospinal excitability when individuals were asked to exercise their upper extremity using a real mirror and virtual mirror. Moreover, we attempted to delineate the role of visual modulation within the virtual environment that affected corticospinal excitability in healthy subjects and stroke patients.
  
  
  METHODS
  A total of 18 healthy subjects and 18 hemiplegic patients were enrolled into the study. Motor evoked potential (MEP)s from transcranial magnetic stimulation were recorded in the flexor carpi radialis of the non-dominant or affected upper extremity using three different conditions: (A) relaxation; (B) real mirror; and (C) virtual mirror. Moreover, we compared the MEPs from the virtual mirror paradigm using continuous visual feedback or intermittent visual feedback.
  
  
  RESULTS
  The rates of amplitude increment and latency decrement of MEPs in both groups were higher during the virtual mirror task than during the real mirror. In healthy subjects and stroke patients, the virtual mirror task with intermittent visual feedback significantly facilitated corticospinal excitability of MEPs compared with continuous visual feedback.
  
  
  CONCLUSIONS
  Corticospinal excitability was facilitated to a greater extent in the virtual mirror paradigm than in the real mirror and in intermittent visual feedback than in the continuous visual feedback, in both groups. This provides neurophysiological evidence supporting the application of the virtual mirror paradigm using various visual modulation technologies to upper extremity rehabilitation in stroke patients.
authors.affiliation: Department of Rehabilitation Medicine, Eulji Hospital, Eulji University School of Medicine Seoul, Seoul, Korea.
authors.forename: Youn Joo
authors.initials: YJ
authors.lastname: Kang
authors.forename: Hae Kyung
authors.initials: HK
authors.lastname: Park
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Taeo
authors.initials: T
authors.lastname: Lim
authors.forename: Jeonghun
authors.initials: J
authors.lastname: Ku
authors.forename: Sangwoo
authors.initials: S
authors.lastname: Cho
authors.forename: Sun I
authors.initials: SI
authors.lastname: Kim
authors.forename: Eun Sook
authors.initials: ES
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D030141:Feedback, Psychological / Q000502:physiology; D005260:Female; D006429:Hemiplegia / Q000209:etiology / Q000503:physiopathology / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009126:Muscle Relaxation / Q000502:physiology; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011712:Pyramidal Tracts / Q000503:physiopathology*; D020521:Stroke / Q000150:complications / Q000503:physiopathology; D000071939:Stroke Rehabilitation; D050781:Transcranial Magnetic Stimulation; D034941:Upper Extremity / Q000503:physiopathology*; D014584:User-Computer Interface