Functional Plasticity of the Motor Cortical Structures Demonstrated by Navigated TMS in Two Patients with Epilepsy

Jyrki P. Mäkelä*, Anne Mari Vitikainen, Pantelis Lioumis, Ritva Paetau, Eero Ahtola, Linda Kuusela, Leena Valanne, Göran Blomstedt, Eija Gaily

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

30 Citations (Scopus)

Abstract

Background: Recently, navigated transcranial magnetic stimulation (nTMS) has been suggested to be useful in preoperative functional localization of motor cortex in patients having tumors close to the somatomotor cortex. Resection of tumors in anatomically predicted eloquent areas without adverse effects have emphasized functional plasticity elicited by intracranial pathology.

Objective: To describe functional plasticity of motor cortex indicated by nTMS in two patients with epilepsy.

Methods: nTMS, functional MRI (fMRI), diffusion-tensor (DT)-tractography and magnetoencephalography (MEG) were utilized to preoperatively localize motor cortical areas in the workup for epilepsy surgery. The localizations were compared with each other, with the cortical anatomical landmarks, and in one patient with invasive electrical cortical stimulation (ECS).

Results: In two out of 19 studied patients, nTMS identified motor cortical sites that differed from those indicated by anatomical landmarks. In one patient, nTMS activated preferentially premotor cortex rather than pathways originating from the precentral gyrus. MEG and fMRI localizations conformed with nTMS whereas ECS localized finger motor function into the precentral gyrus. Resection of the area producing motor responses in biphasic nTMS did not produce a motor deficit. In the other patient, nTMS indicated abnormal ipsilateral hand motor cortex localization and confirmed the functionality of aberrant motor cortical representations of the left foot also indicated by fMRI and DT-tractography.

Conclusion: nTMS may reveal the functional plasticity and shifts of motor cortical function. Epileptic foci may modify cortical inhibition and the nTMS results. Therefore, in some patients with epilepsy, the nTMS results need to be interpreted with caution with regard to surgical planning. (c) 2013 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)286-291
Number of pages6
JournalBrain Stimulation
Volume6
Issue number3
DOIs
Publication statusPublished - 1 May 2013
MoE publication typeA1 Journal article-refereed

Keywords

  • Epilepsy surgery
  • FCD
  • Premotor cortex
  • MEG
  • fMRI
  • Tractography
  • TRANSCRANIAL MAGNETIC STIMULATION
  • ELECTRICAL-STIMULATION
  • DYSGENIC CORTEX
  • HAND
  • LOCALIZATION
  • SURGERY
  • DYSPLASIA
  • BRAIN
  • AREAS
  • REORGANIZATION

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