gms | German Medical Science

67th Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Korean Neurosurgical Society (KNS)

German Society of Neurosurgery (DGNC)

12 - 15 June 2016, Frankfurt am Main

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Cortical language mapping by rTMS compared to fMRI in healthy volunteers

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  • Sebastian Ille - Neurochirurgische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Germany; TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany
  • Nico Sollmann - Neurochirurgische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Germany; TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany; Abteilung für Neuroradiologie, Institut für Radiologie, Klinikum rechts der Isar, Technische Universität München, Germany
  • Claus Zimmer - Abteilung für Neuroradiologie, Institut für Radiologie, Klinikum rechts der Isar, Technische Universität München, Germany
  • Bernhard Meyer - Neurochirurgische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Germany
  • Florian Ringel - Neurochirurgische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Germany
  • Sandro M. Krieg - Neurochirurgische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Germany; TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany

Deutsche Gesellschaft für Neurochirurgie. 67. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), 1. Joint Meeting mit der Koreanischen Gesellschaft für Neurochirurgie (KNS). Frankfurt am Main, 12.-15.06.2016. Düsseldorf: German Medical Science GMS Publishing House; 2016. DocMI.15.07

doi: 10.3205/16dgnc325, urn:nbn:de:0183-16dgnc3258

Published: June 8, 2016

© 2016 Ille et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

Text

Objective: While functional magnetic resonance imaging (fMRI) was considered to be the standard for non-invasive language mapping for a long time, repetitive navigated transcranial magnetic stimulation (rTMS) is an upcoming method. However, most current language models refer to fMRI language mapping data. We therefore compared both modalities for language mapping in healthy subjects.

Method: We performed rTMS and fMRI language mapping in 40 healthy subjects. After assigning language-positive regions to a cortical parcellation system (CPS), we calculated rTMS error rates (ER = errors per stimulations) and fMRI activation rates (AR = blood-oxygen-level-dependent-positive regions per patients) for each CPS region. We defined different error rate thresholds (ERT = ER at which a CPS region was defined as language-positive in terms of rTMS), and used Cohen’s kappa coefficient for the comparison of the two techniques.

Results: The overall kappa for all regions was 0.05 ± 0.06 (mean ± SD). We found the best agreement for both techniques when using the 2-out-of-3 rule (CPS region was defined as language-positive in terms of rTMS if at least 2 out of 3 stimulations led to a language error). However, kappa value for this agreement was only 0.24, describing a fair agreement.

Conclusions: Mapping data by fMRI and rTMS differed significantly and we need to be careful to call one of the two techniques as the true one. However, current language models referring to fMRI data should be reconsidered, and new models should combine data of both techniques.

Note: Sebastian Ille and Nico Sollmann contributed equally.