<meta charset="utf8"></head><body>소아 간질 국소화에서 MEG와 HD-EEG의 통합

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>AIRSTIM unit</td>
			<td>SD Instruments</td>
			<td>N/A</td>
			<td>The SDI AIRSTIM system is an alternative unconditioned stimulus to shock</td>
		</tr>
		<tr>
			<td>Baby Shampoo&#160;</td>
			<td>Johnson&#39;s</td>
			<td>N/A</td>
			<td>Baby Shampoo is as gentle to the eyes as pure water and is specially designed to gently cleanse baby&#8217;s delicate hair and scalp.&#160;</td>
		</tr>
		<tr>
			<td>Control III disinfectant cleaning solution</td>
			<td>Maril Products, Inc.</td>
			<td>http://www.controlthree.com/</td>
			<td>Disinfectant and germicide solution formulated for hospitals</td>
		</tr>
		<tr>
			<td>Elekta Neuromag</td>
			<td>TRIUX</td>
			<td>NM24132A</td>
			<td>Comprehensive bioelectromagnetic measurement system characterized by 306-channel neuromagnetometer for functional brain studies</td>
		</tr>
		<tr>
			<td>FASTRAK</td>
			<td>Polhemus technology</td>
			<td>NS-7806</td>
			<td>Using A/C electromagnetic technology, FASTRAK delivers accurate position and orientation data, with virtually no latency. With a single magnetic source, FASTRAK delivers data for up to four sensors. The source emits an electromagnetic field, sensors within the field of range are tracked in full 6DOF (6 Degrees-Of-Freedom). Setup is simple and intuitive, with no user calibration required.</td>
		</tr>
		<tr>
			<td>Genuine Grass Reusable Cup EEG Electrodes</td>
			<td>Natus Medical, Inc.</td>
			<td>N/A</td>
			<td>Each Genuine Grass EEG Electrode undergoes rigorous mechanical and electrical testing to assure long life for unsurpassed recording clarity and dependability.</td>
		</tr>
		<tr>
			<td>Geodesic Sensor Net</td>
			<td>Electrical Geodesics, Inc.</td>
			<td>S-MAN-200-GSNR-001</td>
			<td>32 to 256 electrodes to place on the human head to aquire dense-array electroencephalography data</td>
		</tr>
		<tr>
			<td>GeoScan Sensor Digitization System</td>
			<td>Electrical Geodesics, Inc.</td>
			<td>8100550-03</td>
			<td>Handheld Scanner and Software for 3D electrode position registration</td>
		</tr>
		<tr>
			<td>Natus Xltek NeuroWorks</td>
			<td>Natus Medical, Inc.</td>
			<td>https://natus.com/</td>
			<td>The Natus NeuroWorks platform simplifies the process of collecting, monitoring and managing data for routine EEG testing, ambulatory EEG, long-term monitoring, ICU monitoring, and research studies.</td>
		</tr>
		<tr>
			<td>Natus NeuroWorks EEG Software</td>
			<td>Natus Medical, Inc.</td>
			<td>https://natus.com/neuro/neuroworks-eeg-software/</td>
			<td>NeuroWorks EEG software simplifies the process of collecting, monitoring, trending and managing EEG testing data, allowing care providers to save time and focus on delivering the best care.</td>
		</tr>
		<tr>
			<td>ROSA ONE Brain</td>
			<td>Zimmer Biomet</td>
			<td>https://www.zimmerbiomet.com/en/products-and-solutions/zb-edge/robotics/rosa-brain.html</td>
			<td>ROSA ONE Brain is a robotic solution to assist surgeons in planning and performing complex neurosurgical procedures through a small drill hole in the skull.&#160;</td>
		</tr>
		<tr>
			<td>Ten20 Conductive Paste</td>
			<td>Weaver and company</td>
			<td>N/A</td>
			<td>Ten20 contains the right balance of adhesiveness and conductivity, enabling the electrodes to remain in place while allowing the transmittance of electrical signals.</td>
		</tr>
	</tbody>
</table>

electromagnetic source imaging in presurgical evaluation of children with drug-resistant epilepsy

Epilepsy is one of the most common and disabling neurological disorders characterized by recurrent and unprovoked seizures that can be either focal or generalized in nature. Despite the availability of several effective pharmacologic therapies (e.g., antiseizure medications [ASMs]), about 20-30% of these patients are unable to control their seizures and suffer from drug-resistant epilepsy (DRE)1. For these patients, epilepsy surgery is the most effective treatment to eliminate seizures; a successful surgery can be achieved through the complete resection (or ablation/disconnection) of the epileptogenic zone (EZ), defined as the minimal area indispensable for the generation of seizures2. Accurate delineation and resection (or ablation/disconnection) of the EZ while preserving the eloquent cortex are crucial factors in ensuring seizure freedom. To establish surgical candidacy, several noninvasive diagnostic tools are used by a multidisciplinary team to define different cortical areas (i.e., irritative zone, seizure onset zone [SOZ], functional deficit zone, and epileptogenic lesion), which serve as indirect approximators of the EZ3. Extra-operative monitoring with intracranial EEG (iEEG) is required when none of these methods unequivocally identify the EZ. The role of iEEG is to define precisely the EZ by localizing the SOZ (i.e., the brain area where clinical seizures generate) and map eloquent brain areas. Yet, it presents serious limitations due to its invasiveness4,5,6, it offers limited spatial coverage, and it needs a clear presurgical localization hypothesis7. As a result, the actual focus and extent of the SOZ may be missed, leading to unsuccessful surgery. Also, its interpretation requires the recording of multiple stereotyped clinical seizures during several days of hospitalization, which increases the chances of complications (e.g., infection and/or bleeding)5. Hence, there is an unmet need to develop reliable and noninvasive localization methods that can provide clinically useful information and overall improve the presurgical evaluation of children with DRE.
Over the last decades, electric and magnetic source imaging (ESI and MSI) have been increasingly utilized in the presurgical evaluation of patients with DRE for the delineation of epileptogenic as well as functional brain areas. Particularly, ESI and MSI allow the reconstruction of neural sources from noninvasive recordings, such as high-density EEG (HD-EEG) and magnetoencephalography (MEG), to help guide surgical planning or iEEG electrode placement. ESI and MSI can be applied for localizing either interictal epileptiform discharges (IEDs), such as spikes and sharp waves, or ictal (seizure) activity. It may further be used for the localization of different functional brain areas involved in sensory, motor, auditory, and cognitive functions. The reconstruction of electrophysiological events, such as IEDs and seizures, allows the identification of the irritative zone (i.e., the brain area where IEDs originate) and the SOZ, respectively, which are considered a valid surrogate for the EZ localization. The localization of the eloquent cortex (i.e., the brain areas indispensable for defined cortical functions)3 allows instead to map the location and extent of eloquent areas with respect to the planned resection and, therefore, reduce in advance potential functional deficits that may be expected from epilepsy surgery8,9,10,11. Several studies investigated the clinical utility of ESI and/or MSI in the presurgical evaluation of epilepsy, and they showed promising findings in the delineation of the EZ12,13,14,15,16,17,18,19. For example, Mouthaan et al.14 performed an extensive meta-analysis using noninvasive data of 11 prospective and retrospective epilepsy studies and reported that these source localization techniques can overall identify the EZ with high sensitivity (82%) and low specificity (53%). Other studies also showed that MSI and ESI can correctly localize the epileptic focus within the resected area in epileptic patients having a normal magnetic resonance imaging (MRI)19,20,21. These localization results are particularly important for those patients who are ineligible for epilepsy surgery due to inconclusive clinical or imaging findings. In summary, ESI and MSI can contribute significantly to the presurgical mapping of epileptogenic as well as functional brain areas in patients with DRE.
Despite these encouraging findings, such techniques are currently performed in only a few tertiary epilepsy centers on a regular basis and are often underutilized in pediatric populations. Moreover, HD-EEG and MEG are rarely recorded simultaneously, although they provide both confirmatory and complementary information. MEG is sensitive to detect superficial sources with tangential orientation but is blind to radially oriented sources located at the gyri or deeper areas of the brain22,23,24,25,26. Furthermore, MEG provides better spatial resolution (millimeters) compared to EEG16,22,25. Unlike EEG signals, MEG signals are reference-free and are essentially unaffected by different conductivities of brain tissues (i.e., meninges, cerebrospinal fluid, skull, and scalp)25,27 providing undistorted measurements of the magnetic fields produced by the brain. On the other hand, EEG can detect sources of all orientations, but it offers lower spatial resolution than MEG and is more susceptible to artifacts26,28. Due to these complementary sensitivities to source orientation and depth, approximately 30% of the epileptiform activity (e.g., IEDs) can only be recorded on MEG but not on EEG, and vice versa26,29,30,31,32. Contrary to EEG, which allows prolonged recordings, capturing clinical seizures with MEG is challenging due to the restricted recording time that is usually insufficient to record ictal events in most patients. Furthermore, artifacts caused by seizure-related head movements can often interfere with the quality of MEG recordings29,33,34,35. On the other hand, MEG recordings are faster and easier compared to EEG, especially in children since there is no need to attach sensors over the children&#39;s head35.
Advances in hardware have made it possible to record simultaneously MEG and HD-EEG data with a high number of sensors (over 550 sensors) covering the whole head. Moreover, modern developments in EEG technologies have minimized the preparation time for HD-EEG to less than a quarter of an hour36. This is particularly important for pediatric populations with challenging behaviors who are unable to stay still for prolonged periods. Furthermore, advancements in software technologies have allowed the combination of ESI and MSI into a single solution, namely electromagnetic source imaging (EMSI), performed on simultaneous HD-EEG and MEG recordings. Several theoretical and empirical studies reported higher source localization accuracy with EMSI than either modality alone13,30,31,37,38,39,40,41. Using different source localization approaches to reconstruct the activity in response to sensory stimuli, Sharon et al.37 found that EMSI had consistently better localization results than either ESI or MSI alone compared to functional MRI&#160;(fMRI), which serves as noninvasive benchmark of precise localization accuracy. The authors suggested that this improved localization is due to the increased number of sensors for solving the inverse solution and the different sensitivity patterns of the two imaging modalities37. Similarly, Yoshinaga et al.31 performed dipole analysis on simultaneous EEG and MEG data of patients with intractable localization-related epilepsy and showed that EMSI provided information that would be not obtainable by using only one modality alone and led to successful localization for epilepsy surgery in one of the patients analyzed. In a prospective blinded study, Duez et al.13 showed that EMSI achieved a significantly higher odds ratio (i.e., probability of becoming seizure-free) compared to ESI and MSI, a localization accuracy &#8805;52%, and a concordance &#8805;53% and &#8805;36% with the irritative and SOZ, respectively. A more recent study from our group42 has shown that EMSI provided superior localization estimates and better outcome prediction performance than either ESI or MSI alone, with localization errors from resection and SOZ of ~8 mm and ~15 mm, respectively. Despite these promising findings, there is a lack of studies that provide the methodological framework regarding EMSI in children with DRE.
This study illustrates the experimental setup for performing simultaneous MEG and HD-EEG recordings as well as the methodological framework for analyzing these data aiming to localize the irritative zone, SOZ, and eloquent brain areas in children with DRE. More specifically, the experimental setups are presented for (i) recording and localizing interictal and ictal epileptiform activity during sleep and (ii) recording visual-, motor-, auditory-, and somatosensory-evoked responses and mapping relevant eloquent brain areas (i.e., visual, motor, auditory, and somatosensory) during a visuomotor task, as well as auditory and somatosensory stimulations. Detailed steps of the data analysis pipeline are further presented for performing EMSI as well as individual ESI and MSI using equivalent current dipole (ECD) and dynamic statistical parametric mapping (dSPM).

<meta charset="utf8"></head><body>저자 스포트라이트: 새로운 바이오마커 및 향상된 지역화를 통한 소아 소아 간질 수술 발전

약물 내성 간질이 있는 소아의 수술 전 평가에서 전자기 소스 이미징

Our main goal of research is to develop novel biomarkers of epilepsy that augment the presurgical evaluation process and improve the surgical outcome of children suffering from drug-resistant epilepsy. We're trying to investigate whether non-invasive methods can precisely localize brain areas that correspond to the epileptogenic tissue. The most recent developments in our field are the ability to record MEG and high-density EEG data simultaneously with a high number of sensors, new EG technologies offering minimal preparation time, which is critical in children, and advanced algorithms that combine electric and magnetic source imaging into a unique solution.We present evidence that combined electric and magnetic source imaging on simultaneous MEG and high-density EEG recordings outperform either modality alone in terms of localized accuracy. This is most likely due to the complementary and confirmatory sensitivity profiles of MEG and easy signals, and the increased number of sensors. We demonstrate a state-of-the-art setup that allows the simultaneous recording of magnetic and electric brain activity with more than 500 sensors covering the entire head.With the setup, we demonstrate the non-invasive localization of interictal and ictal epileptiform activity and the mapping of the local areas so as not to resect during surgery. Our findings will help us understand the complementary and confirmatory information that magnetoencephalography and high-density electroencephalography recordings provide in different clinical scenarios where the localization of the epileptogenic focus is challenging due to the deep location of the source or its radial orientation with respect to the patient's cortical surface.

For children with drug-resistant epilepsy (DRE), seizure freedom relies on the delineation and resection (or ablation/disconnection) of the epileptogenic ...

electromagnetic-source-imaging-presurgical-evaluation-children-with

Research

JoVE Journal

Neuroscience

Electromagnetic Source Imaging in Presurgical Evaluation of Children with Drug-Resistant Epilepsy

1.5K 조회수.  Cook Children’s Health Care System. 우리의 주요 연구 목표는 약물 내성 간질을 앓고 있는 어린이의 수술 결과를 개선하고 수술 전 평가 프로세스를 강화하는 새로운 간질 바이오마커를 개발하는 것입니다. 우리는 비침습적 방법이 간질 생성 조직에 해당하는 뇌 영역을 정확하게 위치시킬 수 있는지 조사하려고 합니다. 이 분야의 가장 최근의 발전은 많은 수의 센서와 함께 MEG 및 고밀?...

비디오: 저자 스포트라이트: 새로운 바이오마커 및 향상된 지역화를 통한 소아 소아 간질 수술 발전

For children with drug-resistant epilepsy (DRE), seizure freedom relies on the delineation and resection (or ablation/disconnection) of the epileptogenic zone (EZ) while preserving the eloquent brain areas. The development of a reliable and noninvasive localization method that provides clinically useful information for the localization of the EZ is, therefore, crucial to achieving successful surgical outcomes. Electric and magnetic source imaging (ESI and MSI) have been increasingly utilized in the presurgical evaluation of these patients showing promising findings in the delineation of epileptogenic as well as eloquent brain areas. Moreover, the combination of ESI and MSI into a single solution, namely electromagnetic source imaging (EMSI), performed on simultaneous high-density electroencephalography (HD-EEG) and magnetoencephalography (MEG) recordings has shown higher source localization accuracy than either modality alone. Despite these encouraging findings, such techniques are performed in only a few tertiary epilepsy centers, are rarely recorded simultaneously, and are underutilized in pediatric cohorts. This study illustrates the experimental setup for recording simultaneous MEG and HD-EEG data as well as the methodological framework for analyzing these data aiming to localize the irritative zone, the seizure onset zone, and eloquent brain areas in children with DRE. More specifically, the experimental setups are presented for (i) recording and localizing interictal and ictal epileptiform activity during sleep and (ii) recording visual-, motor-, auditory-, and somatosensory-evoked responses and mapping relevant eloquent brain areas (i.e., visual, motor, auditory, and somatosensory) during visuomotor task, as well as auditory and somatosensory stimulations. Detailed steps of the data analysis pipeline are further presented for performing EMSI as well as individual ESI and MSI using equivalent current dipole (ECD) and dynamic statistical parametric mapping (dSPM).

Magnetoencephalography (MEG) and high-density electroencephalography (HD-EEG) are rarely recorded simultaneously, although they yield confirmatory and complementary information. Here, we illustrate the experimental setup for recording simultaneous MEG and HD-EEG and the methodology for analyzing these data aiming to localize epileptogenic and eloquent brain areas in children with drug-resistant epilepsy.

연구

신경과학

Simultaneous Magnetoencephalography (MEG) and Electroencephalography (EEG) Recording in Children with Drug-Resistant Epilepsy

To begin, have the subject in a hospital gown sitting comfortably on a wooden chair. Measure the subject's head circumference to select the appropriate EEG net size. Soak the correct size EEG net for five minutes in a solution of warm tap water, electrolytes, and baby shampoo.Using micropore paper tape, place five magnet coils, serving as head position indicators, or HPI, at known locations directly on the scalp. To record the subject's heartbeat, place two ECG electrodes on the right and left side of the chest below the collarbones respectively. For vertical eye movements, or blinks recording.Place two EOG electrodes on the upper and lower side of the right eye respectively. Tape two pairs of non-disposable cup electrodes on the first dorsal interosseous and abductor pollicis brevis of each hand to measure muscle activity during the visuomotor task. Place the reference receiver through the plastic goggles on the subject's head.Through the primary stylus receiver, locate the fiducial anatomical landmarks, the five HPI coils position, and uniformly sample additional scalp points. Before applying the EEG net, put both hands inside the net and spread it. Place the stretched net on the subject's head and adjust its position.Using an EEG impedance meter, ensure that all scalp electrode impedances are in the 0 to 50 kiliohm range. To determine the three dimensional positions of the EEG electrodes, ask the subject to sit comfortably and look straight ahead. On the optical scanner software, select the sensor template that matches the EEG sensor layout used during the recordings and initiate the scanning process.Slowly move the scanner around the subject's head following arced swaths from the top to the bottom to record the physical locations of all sensors. Next, probe the fiducial points and four alignment sensors using the wireless optical probe to align the three dimensional sensors cloud to the selected sensor template. For the resting or sleeping data, set the gantry of the MEG system to the supine position.Transfer the subject inside the magnetically shielded room, or MSR, and assist to sit on the edge of the bed and lie down on it. Gently move the subject's head until it touches the inside of the helmet. Plug the HPI coils, ECG, and EOG electrodes on the corresponding panels of the MEG system.Connect the EEG net to the amplifier unit until it is inside the MSR. Check the measurements of the head's coordinates from the acquisition workstation outside the MSR. For the visuomotor task, set the gantry of the MEG system to the upright position and arrange the MEG chair so that the subject's head is under the gantry.Assist the subject to sit on the non-magnetic and compatible chair. Plug the HPI coils, ECG, EOG, first dorsal, interosseous, and abductor pollicis brevis electrodes on the right panel of the MEG machine. Connect the EEG net to the amplifier unit inside the MSR.Raise the chair using the elevation pedal until the subject's head lightly touches the inside of the helmet. Place the projection screen in front of the subject, and instruct the subject to tap their index finger on the table only when the visual stimulus appears on the screen. Use the same setup for auditory stimulation, and help the subject wear headphones.While listening to the sound trigger, instruct the subject to fixate on the stimuli projected on the screen. For the somatosensory stimulation, attach thin elastic membranes directly to the distal volar parts of three digits of both hands for tactile stimulation. Ask the subject about their video preference to watch on the projector screen.Before starting the recording, close the door of the MSR. Through the voice intercom system, confirm the comfort of the subject inside the MSR, and instruct the subject to maintain a still position for approximately 30 seconds before starting the task. For each recording session, press the recording button on the EEG data acquisition software to begin the EEG recording.Then, press the recording button on the MEG data acquisition software to begin the MEG recording. Finally, press the start button on the stimulation computer software to display the visual stimuli. Record approximately one hour of simultaneous MEG and EEG signals for resting or sleeping data.Similarly, record MEG and EEG signals during the visuomotor task for approximately one hour. For auditory stimulations, record about 20 minutes, and for somatosensory stimulation, record about 14 minutes of simultaneous MEG and EEG data. After recording, ask the subject to sit on a chair outside the MSR.Pull out the EEG net from the subject's head with both hands until it is completely peeled away. On Brainstorm, import the simultaneous MEG and HD EEG signal. Using the standard display setting of 10 seconds per page, mark the negative peak of each IED that occurs on both MEG and EEG recordings, as well as on each modality alone.Localize the underlying generators of the selected interictal spikes using the unconstrained ECD method on the MEG, EEG, and combined MEG and EEG sensors arrays separately. Mark the negative peak of each burst of epileptiform discharges occurring during the ictal event on MEG and EEG, as well as on each modality alone. Similarly, localize the underlying generators of the selected ictal discharges using the unconstrained ECD method on the MEG, EEG, and combined MEG and EEG sensors array separately.For motor cortex mapping, mark the tapping event of the left hand by selecting the first peak of muscle activation different from the baseline on the FDI pair electrode. Next, apply the average reference montage, and estimate the average across stimuli to obtain the event evoked fields and potentials. For each event evoked field and potential, compute the cortical sources on the averaged events using DSPM for the MEG, EEG, and combined MEG and EEG sensors array separately.For a 10-year-old female, EMSI indicated focal clusters of dipoles at the bilateral frontotemporal regions in line with ESI performed on benchmark IEEG. For a 13-year-old male, EMSI revealed localization of the ictal onset within the temporal lobe concordant with ESI on benchmark IEEG. In a 15-year-old female, EMSI performed on the averaged visual, motor, auditory, and somatosensory evoked responses showed maximal cortical activation at the eloquent regions involved.