title: Deterioration of hemiparesis after recurrent stroke in the unaffected hemisphere: Three further cases with possible interpretation.
abstract: BACKGROUND
  The concept of neural reorganization after brain damage is already well established, and many previous studies have successfully reported the translocation of the neural activation in the motor-related cortices during motor tasks using functional imaging modalities. Several primate and human studies have suggested the formation of newly reorganized tracts in the ipsilesional or contralesional hemisphere, but the mechanism for the formation of these tracts is still largely unknown.
  
  
  METHODS
  Three acute stroke patients who presented with abrupt deterioration of their right-sided hemiparesis due to the infarcts following a recurrent stroke in the originally unaffected hemisphere were studied using magnetic resonance imaging (MRI), MR angiography and single-photon emission CT. The relationship between the neurological symptom on admission and the precise location of the new infarct was carefully investigated from the perspective of reorganization.
  
  
  RESULTS
  Diffusion-weighted MRI showed a new subcortical infarct in the right hemisphere contralateral to the initial stroke in all patients. These new lesions involved the thalamus, globus pallidus or corona radiata, sparing the area of the internal capsule. T2-weighed MRI on admission showed an old infarct in the left middle cerebral artery territory, which had caused the original right-sided hemiparesis.
  
  
  CONCLUSIONS
  It is proposed that the 'extrapyramidal' motor pathway in the unaffected hemisphere is associated with poststroke neural reorganization.
authors.affiliation: Department of Neurology, Kansai Rosai Hospital, Hyogo, Japan. shiroyamm@ybb.ne.jp
authors.forename: Shiro
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Masashi
authors.initials: M
authors.lastname: Takasawa
authors.forename: Koji
authors.initials: K
authors.lastname: Kajiyama
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Baron
authors.forename: Takenori
authors.initials: T
authors.lastname: Yamaguchi
mesh_terms: D000208:Acute Disease; D000368:Aged; D001921:Brain / Q000098:blood supply / Q000473:pathology; D002544:Cerebral Infarction / Q000150:complications; D038524:Diffusion Magnetic Resonance Imaging; D004525:Efferent Pathways / Q000503:physiopathology*; D005116:Extrapyramidal Tracts / Q000503:physiopathology*; D005121:Extremities / Q000503:physiopathology; D007839:Functional Laterality; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D010291:Paresis / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D020127:Recovery of Function; D012008:Recurrence; D020521:Stroke / Q000150:complications* / Q000209:etiology / Q000473:pathology; D015899:Tomography, Emission-Computed, Single-Photon