TMS-EEG evoked potentials (TEPs) in Iceland

29th of Sept 2017 Reykjavik Iceland

TMS-EEG evoked potentials (TEP) were performed during a joint meeting of Clinical Neurophysiology Unit team (Neurophysiology Plus Iceland) and Icelandic Center of Clinical Neurophysiology from Reykjavik University.
The meeting was organized by Assist Prof Dr Paolo Gargiulo (Director of Institute of Biomedical and Neural Engineering, Reykjavik University & Landspitali) and had as participants Dr Magnús Kjartan Gíslason & MSc Thorsteinn Geirsson (NeckCare), Aron Dalin Jónasson MSc, Hildigunnur Katrinardóttir MSc & Ovidiu C. Banea MD (Neurophysiology Lab Landspitali and Reykjavik University) and Egill Axfjörður Friðgeirsson, PhD Student University of Amsterdam.

First TMS-EMG was performed to achieve the correct out of maximum TMS intensity necessary to evoke MEP into hand thenar muscles

Using 100% RMT TMS-EEG evoked potentials were recorded. This trial was performed on experimental basis within the expert team in a healthy subject who previously accepted the test. Another 15-20 voluntary healthy subjects will be tested on both TMS-EMG and TMS-EEG protocols in accordance with World Medical Association (WMA) Declaration of Helsinki, a statement of ethical principles for medical research involving human subjects.

The future joint applied science clinical study will be developed after two international specific trainings and meetings in Denmark (Nov 2017) and France (January 2018). The aim is to assess biological neural networks (BNN) in patients with brain tumors and symptomatic epilepsy as a preoperative safety assessment of the functional brain tissue and effective connectivity in order to improve actual procedures (motor  & speech mapping and fMRI) and avoid new neurological deficit. Main collaborators of this challenging Icelandic medical research and clinical study are Neurosurgery Department of National University Hospital of Iceland (Drs Ingvar Hakon Ólafsson & Elfar Ulfarsson) and Neurosurgery Department of del Mar Hospital Barcelona, Spain (Dr Gerard Conesa). Scientific support and research specific feedback is given by Dr Eric Wassermann (NINDS/NIH; Bethesda, United States) and Prof Dr Elías Ólafsson (Head of Neurology Department, National University Hospital of Iceland).

Preoperative Neuronavigation with TMS using operating room system in Iceland

Reykjavik, 13th of July 2017

by Neurophysiology Plus

To avoid a new neurological deficit after a brain growing tumor surgery located in or near eloquent brain areas (speech, motor, visual cortex) the surgeon uses now intraoperative neuromonitoring complementary procedures performed together with clinical neurophysiology team in the operating room.

In 1998, Sawaya et al published the tumor functional grade classification after a scheme developed at the Anderson Cancer Center in Houston Texas based on the tumor location relative to the brain function as following: Grade I non-eloquent brain: Frontal or temporal polar regions, Right parieto-occipital regions, Cerebellar hemispheres lesions; Grade II near eloquent brain: Near motor or sensory cortex, Near calcarine fissure, Near speech center, Corpus callosum, Near dentate nucleus, Near brainstem, including supplementary motor area if was investigated with preoperative magnetic resonance; Grade III eloquent brain: Motor/Sensory cortex, Visual center, Speech center, Internal capsule, Basal ganglia, Hypothalamus/thalamus, Brainstem, Dentate nucleus.

The preoperative studies used to identify the structure and the "function" of the eloquent brain are MRI, fMRI, CT, DatScan, SPECT, PET, TMS. From all these TMS-EMG and TMS-EEG modalities are used for motor mapping and speech mapping or EEG temporal related evoked potentials. The results, the identified motor hot-spots or speech area are then saved and used in operating room by neurosurgeon.

Source: Medtronic

Neuro-Navigated TMS preoperative mapping using same operating room system

13th of July 2017

If eloquent brain areas and motor cortex hot-spots with Talairach coordinates are already set on the patient MRI (structural model of the brain) before surgery the neurophysiology and neurosurgery team will use them when proposing the surgery and during the resection of tumors or abnormal (non-functional) tissues.

In Iceland, preoperative motor mapping started in January 2017 (here) and recently a team formed by Ingvar Hakón Ólafsson, Aron Björnsson, Ágúst H. Guðmundsson (Intermedica/Medtronic), David B., Aron Dalin Jónasson and Ovidiu C. Banea could prove the combination of operating room neuronavigation system (Medtronic) with TMS motor mapping and Intraoperative device (Nim Eclipse Medtronic).

The pilot study was successful and was performed in surgery room. In close future the preoperative neuro-navigated mapping will be used for the proposed patients before surgery time.