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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Mapping visuospatial attention – the greyscales task combined with repetitive navigated transcranial magnetic stimulation

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  • Katrin Giglhuber - Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Germany; TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany
  • Stefanie Maurer - Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Germany; TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany
  • Sebastian Ille - Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Germany; TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Germany
  • Claus Zimmer - Section of Neuroradiology, Department of Radiology, Klinikum rechts der Isar, TU München, Germany
  • Bernhard Meyer - Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Germany
  • Sandro M. Krieg - Department of Neurosurgery, 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. DocP 104

doi: 10.3205/16dgnc479, urn:nbn:de:0183-16dgnc4790

Published: June 8, 2016

© 2016 Giglhuber 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: Repetitive navigated transcranial magnetic stimulation (rTMS) is increasingly used for cortical language mapping. This investigation aims to assess rTMS for the mapping of visuospatial attention by use of the greyscales task.

Method: Ten healthy subjects underwent rTMS mapping (5 Hz/10 pulses) of 52 cortical spots on each hemisphere; each spot was stimulated 10 times. Visuospatial attention was tested by the greyscales task: pairs of horizontal rectangles shaded continuously from black at one end to white at the other, mirror-reversed. Task pictures were displayed tachistoscopically for 50 ms time-locked to rTMS pulses. On each greyscales pair, the subject was asked to report which of the two rectangles appeared darker overall (by saying ‘top’ or ‘bottom’). Responses were categorized into leftward and rightward depending on whether the subject had chosen the rectangle with the darker end on the left or the right.

Results: Scores were calculated as difference between rightward and leftward responses divided by their total number and ranged from -1.00 (leftward bias) to 1.00 (rightward bias). During baseline performance 9 out of 10 subjects showed classical pseudoneglect to the left (mean score -0.59 ± 0.51). During rTMS mapping we observed deviations from the baseline score in all subjects. Overall rTMS of the right hemisphere elicited stronger effects than rTMS of the left hemisphere (0.42 ± 0.08 vs. 0.29 ± 0.08; p<0.0001). According to amount, rightward deviations were higher than deviations to the left (0.55 ± 0.25 vs. 0.23 ± 0.07; p<0.0001). Yet, leftward deviations occurred significantly more often (p<0.0001).

Conclusions: The greyscales task combined with rTMS provides a useful tool to non-invasively detect cortical areas eloquent for visuospatial attention. Future clinical implications have to be further evaluated.