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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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Clinical factors affecting the resting motor threshold in preoperative nTMS motor mapping

Meeting Abstract

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  • Nico Sollmann - Neurochirurgische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Germany
  • Noriko Tanigawa - Faculty of Linguistics, Philology, & Phonetics, University of Oxford, U.K.
  • Lucia Bulubas - 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
  • Bernhard Meyer - 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

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. DocDI.13.01

doi: 10.3205/16dgnc173, urn:nbn:de:0183-16dgnc1732

Published: June 8, 2016

© 2016 Sollmann 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: The correct determination of the individual resting motor threshold (RMT) as a correlate of cortical excitability plays a crucial role in the spatial resolution of neurosurgical motor mapping by navigated transcranial magnetic stimulation (nTMS). However, several factors can have a significant impact on the RMT, but there is no systematic analysis of influencing factors among brain tumor patients available so far.

Method: To better understand potential influencing factors of the RMT, the present investigation analyzed thirteen clinical parameters that might underlie the variability of RMT in a cohort of 100 brain tumor patients with motor eloquent lesions that underwent preoperative nTMS mapping with a standardized stimulation protocol in our department. To determine the extent of the non-overlapping contribution of each factor, multiple regression analysis was performed by taking the forward step-wise model comparison approach.

Results: Patient's gender and antiepileptic medication (AED) were common factors in accounting for the RMT variability regardless of the mapped muscles (male < female; Keppra < no AED < non-Keppra AEDs). For specific muscles, motor deficit was the third common factor (no motor deficit < motor deficit). Other factors specific to certain muscles were tumor side (right hemisphere tumor < left hemisphere tumor), edema (edema < no edema), and recurrent tumor (no recurrence < recurrence).

Conclusions: Among thirteen potential influencing factors, six have proven to be closely related to RMT variability. This finding can be crucial in RMT selection during remapping, for instance, but also provides insights into the nature of the RMT in general.