title: The right inferior frontal gyrus and poststroke aphasia: a follow-up investigation.
abstract: OBJECTIVE
  Recently, a combined repetitive transcranial magnetic stimulation (rTMS) and activation positron emission tomography (PET) study showed essential language function of the right inferior frontal gyrus (IFG) in some right-handed acute poststroke aphasics. We reexamined these patients in the chronic phase to test whether the right IFG remained essential for language performance.
  
  
  METHODS
  We reexamined 9 male right-handed patients, age 41 to 75 years, with aphasia 8 weeks after left hemispheric stroke. rTMS was performed over the maximum activation within the left and right IFG as defined by (15)[O]water PET to interfere with language function. A positive rTMS effect was defined as increased reaction time latency or error rate in the semantic task relative to no stimulation.
  
  
  RESULTS
  PET activations of the IFG were observed on the left (2 patients) and bilaterally (7). During rTMS interference over the left IFG, all patients had positive TMS effects, indicating that the left IFG remained essential. Stimulation over the right IFG yielded positive rTMS effects in 2 patients with persisting right IFG activation. Two patients with positive rTMS effects over the right side in the initial study did not show these effects at follow-up. Language performance improved in all patients.
  
  
  CONCLUSIONS
  Successful regeneration from poststroke aphasia seems to depend more on the integration of available language-related brain regions than on recruiting new brain regions during the rehabilitation process. Restoration of the left hemisphere network seems to be more effective, although in some cases, right hemisphere areas are integrated successfully.
authors.affiliation: Department of Neurology, University of Cologne, Cologne, Germany. L.Winhuisen@pet.mpin-koeln.mpg.de
authors.forename: Lutz
authors.initials: L
authors.lastname: Winhuisen
authors.forename: Alexander
authors.initials: A
authors.lastname: Thiel
authors.forename: Birgit
authors.initials: B
authors.lastname: Schumacher
authors.forename: Josef
authors.initials: J
authors.lastname: Kessler
authors.forename: Jobst
authors.initials: J
authors.lastname: Rudolf
authors.forename: Walter F
authors.initials: WF
authors.lastname: Haupt
authors.forename: Wolf D
authors.initials: WD
authors.lastname: Heiss
mesh_terms: D000328:Adult; D000368:Aged; D001037:Aphasia / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000503:physiopathology; D005500:Follow-Up Studies; D005625:Frontal Lobe / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007802:Language; D007807:Language Tests; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011930:Reaction Time / Q000502:physiology; D020127:Recovery of Function; D020521:Stroke / Q000150:complications* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013995:Time; D050781:Transcranial Magnetic Stimulation; D014705:Verbal Behavior / Q000502:physiology