Assessing Brain Hyperexcitability with Transcranial Magnetic Stimulation and Electroencephalography

Abstract

Source: Shafi, M. M., et al. A Multimodal Imaging- and Stimulation-based Method of Evaluating Connectivity-related Brain Excitability in Patients with Epilepsy. J. Vis. Exp. (2016)

The video demonstrates the procedure for using transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to assess neuronal excitability in patients with epilepsy. It details the steps for aligning the patient’s head with a pre-recorded brain scan, positioning the TMS coil over a functionally connected cortical target, and applying stimulation to activate neural circuits. The process includes tracking motor responses, recording EEG signals, and comparing brain activity with that of healthy controls to identify hyperexcitability and localize the seizure-onset zone.

Protocol

All procedures involving human participants have been performed in compliance with the institutional, national, and international guidelines for human welfare and have been reviewed by the local institutional review board.

1. Subject Selection

1. Patient selection for research protocol.
   1. Identify patients with active epilepsy (seizures within the past year) or a history of remote epilepsy (prior seizures, but with no seizures in the past five years either on or off medication) and periventricular nodular heterotopia on structural brain imaging.
   2. Exclude patients without any history of seizures. Also, exclude pati....

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
3T MRI scanner
MRI functional connectivity software
MRI image viewing software			MRICron
Transcranial Magnetic Stimulator	Nexstim	eXimia Stimulator	Can use stimulators from other suppliers e.g. Magventure, Magstim
MRI neuronavigation system	Nexstim	NBS v3.2.1	Alternative MRI neuronavigation system e.g. Brainsight, Localite
TMS-compatible EEG system	Nexstim	Eximia EEG	Alternatives: Brain Products, Synamps, ANT
Matlab	Mathworks	R2012b	Alternatives: Octave
EEGLab
Minimum Norm Estimate (MNE) software
FreeSurfer