Functional language shift to the right hemisphere in patients with language-eloquent brain tumors.

Krieg, Sandro M; Sollmann, Nico; Hauck, Theresa; Ille, Sebastian; Foerschler, Annette; Meyer, Bernhard; Ringel, Florian

doi:10.1371/journal.pone.0075403

Title:: Functional language shift to the right hemisphere in patients with language-eloquent brain tumors.
Document type:: Journal Article; Research Support, Non-U.S. Gov't
Author(s):: Krieg, Sandro M; Sollmann, Nico; Hauck, Theresa; Ille, Sebastian; Foerschler, Annette; Meyer, Bernhard; Ringel, Florian
Abstract:: Language function is mainly located within the left hemisphere of the brain, especially in right-handed subjects. However, functional MRI (fMRI) has demonstrated changes of language organization in patients with left-sided perisylvian lesions to the right hemisphere. Because intracerebral lesions can impair fMRI, this study was designed to investigate human language plasticity with a virtual lesion model using repetitive navigated transcranial magnetic stimulation (rTMS).Fifteen patients with lesions of left-sided language-eloquent brain areas and 50 healthy and purely right-handed participants underwent bilateral rTMS language mapping via an object-naming task. All patients were proven to have left-sided language function during awake surgery. The rTMS-induced language errors were categorized into 6 different error types. The error ratio (induced errors/number of stimulations) was determined for each brain region on both hemispheres. A hemispheric dominance ratio was then defined for each region as the quotient of the error ratio (left/right) of the corresponding area of both hemispheres (ratio >1 = left dominant; ratio <1 = right dominant).Patients with language-eloquent lesions showed a statistically significantly lower ratio than healthy participants concerning "all errors" and "all errors without hesitations", which indicates a higher participation of the right hemisphere in language function. Yet, there was no cortical region with pronounced difference in language dominance compared to the whole hemisphere.This is the first study that shows by means of an anatomically accurate virtual lesion model that a shift of language function to the non-dominant hemisphere can occur.
Journal title abbreviation:: PLoS ONE
Year:: 2013
Journal volume:: 8
Journal issue:: 9
Pages contribution:: e75403
Language:: eng
Fulltext / DOI:: doi:10.1371/journal.pone.0075403
Pubmed ID:: http://view.ncbi.nlm.nih.gov/pubmed/24069410
Print-ISSN:: 1932-6203
TUM Institution:: Fachgebiet Neuroradiologie (Prof. Zimmer); Neurochirurgische Klinik und Poliklinik
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