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

Retest-reliability and tolerability of 10, 30 and 50 Hz repetitive transcranial magnetic stimulation (rTMS) for language mapping: a preclinical study

Meeting Abstract

  • Julia Pieczewski - University of Cologne, Center of Neurosurgery, Cologne, Germany
  • Charlotte Nettekoven - University of Cologne, Center of Neurosurgery, Cologne, Germany; Research Center Juelich, INM-3, Jülich, Germany
  • Volker Neuschmelting - University of Cologne, Center of Neurosurgery, Cologne, Germany
  • Kristina Thiele - University of Cologne, Faculty of Human Sciences, Speech-Language-Pathology and Rehabilitation, Cologne, Germany
  • Roland Goldbrunner - University of Cologne, Center of Neurosurgery, Cologne, Germany
  • Carolin Weiss Lucas - University of Cologne, Center of Neurosurgery, Cologne, 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.15.05

doi: 10.3205/16dgnc323, urn:nbn:de:0183-16dgnc3232

Published: June 8, 2016

© 2016 Pieczewski et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at



Objective: Navigated repetitive transcranial stimulation (rTMS) represents a rather novel approach to depict highly language-relevant cortical sites non-invasively. Due to low specificity and considerable painfulness when stimulating with the commonly used 5-10 Hz rTMS, rTMS-language-mapping is still limited in its clinical use. In order to define a better tolerable protocol, we compared 5-10 Hz with higher-frequency rTMS regimes regarding discomfort/pain, test-retest reliability, rate and site of distinct evoked language errors.

Method: 13 right-handed, healthy subjects were investigated in 3 sessions (spaced by 2-5 d / 21-40 d). 10 Hz, 30 Hz and 50 Hz rTMS were applied over the left hemisphere, continuously covering facial (pre-)motor and language-related cortical areas. After defining the „motor inhibition threshold“ (MIT) which mirrors the efficacy of cortical inhibition, online-rTMS was applied during a picture-naming task in a randomized sequence. Evoked language errors (ELE) were rated by two independent raters using post-hoc video analysis according to a-priori defined error categories. At the end of each exam, the volunteers were asked to rate the mean and maximum level of discomfort on a 0-10 numeric rating scale (NRS).

Results: Better tolerability was observed for the 30 & 50 Hz rTMS protocols than for 10 Hz rTMS. Moreover, 30 and 50 Hz rTMS reliably evoked tongue movement disruption (Intraclass correlation coeff. = 0.65) at lower stimulation intensities compared to 10 Hz rTMS (p<0.01). Regarding ELE, the interrater reliability was good (Cohen’s kappa = 0.7). The rates of ELE did not differ between 10 and 30 Hz rTMS. However, lower ELE rates were observed for the 50 Hz rTMS as compared to 10 and 30 Hz for speech motor deficits, hesitations and phonemic paraphasias (p<0.05). Spatial reliability of ELE was generally low, showing considerable variability across subjects and error categories.

Conclusions: Higher-frequency rTMS (30/50 Hz) may enable cortical inhibition at a more favourable pain-effect ratio than 10 Hz rTMS. Despite good test-retest reliability of the event rates, the low spatial reliability of ELE requires critical discussion.