title: Hemispheric language dominance measured by repetitive navigated transcranial magnetic stimulation and postoperative course of language function in brain tumor patients.
abstract: OBJECTIVE
  The resection of left-sided perisylvian brain lesions harbors the risk of postoperative aphasia. Because it is known that language function can shift between hemispheres in brain tumor patients, the preoperative knowledge of the patient's language dominance could be helpful. We therefore investigated the hemispheric language dominance by repetitive navigated transcranial magnetic stimulation (rTMS) and surgery-related deficits of language function.
  
  
  METHODS
  We pooled the bicentric language mapping data of 80 patients undergoing the resection of left-sided perisylvian brain lesions in our two university neurosurgical departments. We calculated error rates (ERs; ER = errors per stimulations) for both hemispheres and defined the hemispheric dominance ratio (HDR) as the quotient of the left- and right-sided ER (HDR >1= left dominant; HDR <1= right dominant). The course of the patient's language function was evaluated and correlated with the preoperative HDR.
  
  
  RESULTS
  Only three of 80 patients (4%) presented with permanent surgery-related aphasia and 24 patients (30%) with transient surgery-related aphasia. The mean HDR (± standard deviation) of patients with new aphasia after five days was significantly higher (1.68±1.07) than the HDR of patients with no new language deficit (1.37±1.08) (p=0.0482). With a predefined cut-off value of 0.5 for HDR, we achieved a sensitivity for predicting new aphasia of 100%.
  
  
  CONCLUSIONS
  A higher preoperative HDR significantly correlates with an increased risk for transient aphasia. Moreover, the intensive preoperative workup in this study led to a considerably low rate of permanent aphasia.
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany. Electronic address: Sebastian.Ille@tum.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ille
authors.affiliation: Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Electronic address: Nataliia.Kulchytska@charite.de.
authors.forename: Nataliia
authors.initials: N
authors.lastname: Kulchytska
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany. Electronic address: Nico.Sollmann@tum.de.
authors.forename: Nico
authors.initials: N
authors.lastname: Sollmann
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany. Electronic address: Regina.Wittig@online.de.
authors.forename: Regina
authors.initials: R
authors.lastname: Wittig
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany. Electronic address: Eva_Beurskens@hotmail.com.
authors.forename: Eva
authors.initials: E
authors.lastname: Beurskens
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany. Electronic address: Vicki.Butenschoen@tum.de.
authors.forename: Vicki M
authors.initials: VM
authors.lastname: Butenschoen
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany. Electronic address: Florian.Ringel@tum.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Ringel
authors.affiliation: Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Electronic address: Peter.Vajkoczy@charite.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Vajkoczy
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany. Electronic address: Bernhard.Meyer@tum.de.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meyer
authors.affiliation: Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Electronic address: Thomas.Picht@charite.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Picht
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany. Electronic address: Sandro.Krieg@tum.de.
authors.forename: Sandro M
authors.initials: SM
authors.lastname: Krieg
mesh_terms: D000328:Adult; D000368:Aged; D001037:Aphasia / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology* / Q000503:physiopathology* / Q000601:surgery; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D005500:Follow-Up Studies; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects; D012372:ROC Curve; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Hemispheric dominance ratio; Language outcome; Tumor resection; nTMS; rTMS language mapping