title: Dissociated language functions: a matter of atypical language lateralization or cerebral plasticity?
abstract: OBJECTIVE
  The left hemisphere is generally considered to harbor language functions. Atypical cortical language lateralization is mainly demonstrated in left-handed and ambidextrous individuals, whereas dissociated language functions have been reported in association with brain injuries as a part of the reorganization process. We present a thoughtful discussion on the underlying mechanisms of dissociated language functions through an illustrative case of dissociated expressive language.
  
  
  METHODS
  A 31-year-old left-handed woman presented with a recurrent left frontal glioma. Preoperative language functional magnetic resonance imaging (fMRI) panel revealed right-sided dominance for two different language tasks (verbal fluency and visual naming), and the word chain task demonstrated maximal activation in the left hemisphere at the posterior margin of the tumor. The patient was operated on awake to assess language functions intraoperatively. Preoperative fMRI findings were confirmed revealing a task-specific dissociation of expressive language functions. Surgical resection was taken to the functional boundaries. Postoperatively, no language dysfunction occurred.
  
  
  CONCLUSIONS
  Dissociated language functions are prone to occur in long-standing lesions. Different patterns of dissociation may be encountered due to interindividual particularities and cerebral plasticity. The presented patient is unique by demonstrating new insight into expressive language dissociation, emphasizing the role of a preoperative language fMRI panel and the capability of intraoperative language mapping for identifying special language networks.
authors.affiliation: Department of Neurosurgery, Eberhard Karls University Hospital, Tübingen, Germany.
authors.forename: Marcus Andre
authors.initials: MA
authors.lastname: Acioly
authors.affiliation: Department of Neurosurgery, Eberhard Karls University Hospital, Tübingen, Germany.
authors.forename: Alireza
authors.initials: A
authors.lastname: Gharabaghi
authors.affiliation: Department of Neurosurgery, Eberhard Karls University Hospital, Tübingen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Zimmermann
authors.affiliation: Department of Neuroradiology, Eberhard Karls University Hospital, Tübingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Erb
authors.affiliation: Department of Neuroradiology, Eberhard Karls University Hospital, Tübingen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Heckl
authors.affiliation: Department of Neurosurgery, Eberhard Karls University Hospital, Tübingen, Germany.
authors.forename: Marcos
authors.initials: M
authors.lastname: Tatagiba
mesh_terms: D000328:Adult; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology* / Q000601:surgery; D007839:Functional Laterality / Q000502:physiology*; D005910:Glioma / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007802:Language; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D009473:Neuronal Plasticity / Q000502:physiology*