gms | German Medical Science

68th Annual Meeting of the German Society of Neurosurgery (DGNC)
7th Joint Meeting with the British Neurosurgical Society (SBNS)

German Society of Neurosurgery (DGNC)

14 - 17 May 2017, Magdeburg

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Plasticity of motor representations in patients with brain lesions: a navigated TMS study

Meeting Abstract

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  • Lucia Bulubas - Klinikum rechts der Isar TU München , Klinik für Neurochirurgie, München, Deutschland
  • Nico Sollmann - Klinikum rechts der Isar TU München , Klinik für Neurochirurgie, München, Deutschland
  • Noriko Tanigawa - Faculty of Linguistics, Philology & Phonetics, University of Oxford, Oxford, United Kingdom
  • Bernhard Meyer - Klinikum rechts der Isar, Technische Universität München, Neurochirurgische Klinik und Poliklinik, München, Deutschland
  • Sandro Krieg - Klinikum rechts der Isar TU München , Klinik für Neurochirurgie, München, Deutschland

Deutsche Gesellschaft für Neurochirurgie. Society of British Neurological Surgeons. 68. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), 7. Joint Meeting mit der Society of British Neurological Surgeons (SBNS). Magdeburg, 14.-17.05.2017. Düsseldorf: German Medical Science GMS Publishing House; 2017. DocMi.09.01

doi: 10.3205/17dgnc420, urn:nbn:de:0183-17dgnc4205

Published: June 9, 2017

© 2017 Bulubas 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 present study investigates the spatial distributions of motor representations in terms of tumor-induced brain plasticity by analyzing navigated transcranial magnetic stimulation (nTMS) motor maps derived from 100 patients with motor eloquently located brain tumors in or adjacent to the precentral gyrus (PrG).

Methods: 8,774 motor evoked potentials (MEPs) were elicited in 6 muscles of the upper and lower extremity by stimulating four gyri (superior frontal gyrus=SFG, middle frontal gyrus=MFG, PrG, and postcentral gyrus=PoG) in patients with five possible tumor locations (frontal tumor: n=24, Rolandic tumor: n=35, postcentral tumor: n=17, temporal tumor: n=5, and parietal tumor: n=19). Regarding the MEP frequency of each muscle-gyrus subdivision per patient, the expected frequency was 3.53 (8,774 divided by 100 patients, further divided by 6 muscles and 4 gyri). Accordingly, the patient ratio for each subdivision was calculated by defining the per-patient minimum data points as 3.

Results: 60.71% of the MEPs were elicited in the PrG. The overall and tumor-location specific patient ratios were rather high (APB-in-PrG: 93.00%) and balanced, indicating robust motor representations in the PrG. Regarding the motor representations in SFG and MFG, the overall patient ratios were much lower (APB-in-SFG: 16.00%, APB-in-MFG: 36.00%). The tumor-location specific patient ratios were higher for frontal tumors in both gyri (ADM-in-SFG 29.17%, ADM-in-MFG 50.00%) than for other tumor locations. This suggests that the finger representation reorganization in these frontal gyri, which corresponds to location of dorsal premotor areas, might be due to within-premotor reorganization rather than relocation of motor function from PrG into premotor areas one might expect from the Rolandic tumors.

Conclusion: Reorganization of the finger motor representations might be limited along the middle-to-dorsal dimension of the dorsal premotor areas (posterior MFG and SFG) and might not cross rostrally from the primary motor cortex (PrG) to the dorsal premotor cortex.