Medizinische Universität Graz - Research portal
Selected Publication:
Freigang, S.
A case report on the effect of priming a continuous theta burst stimulation (cTBS) used for functional language mapping with navigated transcranial magnetic stimulation (nTMS) in glioma patients
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2018. pp. 114
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- Authors Med Uni Graz:
- Freigang Sascha
- Advisor:
- Mokry Michael
- von Campe Gord
- Altmetrics:
- Abstract:
- Objective: Neurosurgical decision making relies on various diagnostic methods prior to surgery. Direct cortical stimulation (DCS) is considered the gold standard in brain mapping to gain information on functional cortical areas that might be affected by surgery. This thesis focuses on navigated transcranial magnetic stimulation (nTMS) as a method for preoperative language mapping in braintumour patients who will undergo awake surgery. Brain stimulation techniques critically depend on the prior state of neuronal excitability. The main goal of the study is to evaluate an inhibitory TMS paradigm called continuous theta burst stimulation (cTBS) for language mapping in combination with priming. Method: nTMS language mapping will be performed on 12 right-handed patients scheduled for awake surgery to remove a left-hemispheric lesion (tumour). TMS targets are determined by fMRI hotspots and anatomical references. During TMS and awake surgery the patients perform an object naming task. cTBS will be applied in two sessions, with and without priming, separated by at least 1 week. Both mappings provided by TMS and DCS will be compared subsequently. Result: The case report stands exemplary for the protocol used. TMS could induce speech arrest in the inferior frontal gyrus and precentral gyrus, with induced minor errors also in other sites. In the TMS session without priming, 37,5% of the stimulated targets had positive findings. With priming, the total error rate (positive response) decreased to 12,5%. The concordance of TMS and the DCS mapping was high. Conclusion: Definite results of the underlying study still need to be confirmed using a larger subject cohort. Observations of the case report are: cTBS is capable of eliciting language errors; DCS and TMS concordance looks promising; priming decreases the effectiveness of eliciting language errors; TMS appears be a useful tool in the preoperative assessment in brain-tumour patients. Further studies are needed with regards to intensity, coil position and other TMS paradigms to create an optimal standardized protocol.