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Brinkmann BH. Technical Considerations in EEG Source Imaging. J Clin Neurophysiol 2024; 41:2-7. [PMID: 38181382 DOI: 10.1097/wnp.0000000000001029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2024] Open
Abstract
SUMMARY EEG source imaging is an established technique for identifying the origin of interictal and ictal epileptiform discharges in patients with epilepsy, and it is an important tool in neurophysiology research. Accurate and reliable EEG source imaging requires appropriate choices of how the head, skull, and scalp are modeled, and understanding of the different approaches to modeling is important to guide these choices. Similarly, numerous different approaches to modeling the electrical sources within the brain exist, and appropriate understanding of the strengths and limitations of each are essential to obtaining accurate, reliable, and interpretable solutions. This review aims to describe the essential theoretical basis for these head and source models while also discussing the practical implications of each in clinical or research applications.
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Affiliation(s)
- Benjamin H Brinkmann
- Departments of Neurology and Physiology and Biomedical Engineering, Mayo Clinic, Alfred 9-441C, SMH; 200 First Street SW, Rochester, Minnesota, U.S.A
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van de Velden D, Heide EC, Bouter C, Bucerius J, Riedel CH, Focke NK. Effects of inverse methods and spike phases on interictal high-density EEG source reconstruction. Clin Neurophysiol 2023; 156:4-13. [PMID: 37832322 DOI: 10.1016/j.clinph.2023.08.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 08/15/2023] [Accepted: 08/24/2023] [Indexed: 10/15/2023]
Abstract
OBJECTIVE To determine the effect of inverse methods and timepoints of interictal epileptic discharges (IEDs) used for high-density electric source imaging (hd-ESI) in pharmacoresistant focal epilepsies. METHODS We retrospectively evaluated the hd-ESI and [18F]fluorodeoxyglucose positron emission tomography (18FDG-PET) of 21 operated patients with pharmacoresistant focal epilepsy (Engel I). Volumetric hd-ESI was performed with three different inverse methods such as the inverse solution linearly constrained minimum variance (LCMV, a beamformer method), standardized low resolution electromagnetic tomography (sLORETA) and weighted minimum-norm estimation (wMNE) and at different IED phases. Hd-ESI accuracy was determined by volumetric overlap and distance between hd-ESI source maximum, as well as 18FDG-PET hypometabolic region relative to the resection zone (RZ). RESULTS In our cohort, the shortest distances and greatest volumetric overlaps to the RZ were found in the half-rise and peak-phase for all inverse methods. The distance to the RZ was not different between the centroid of the clinical hypothesis-based cluster and the source maximum in peak-phase. However, the distance of the hypothesis-based cluster was significantly shorter compared to the cluster selected by the smallest p-value. CONCLUSIONS Hd-ESI provides the greatest accuracy in determining the RZ at the IED half-rise and peak-phase for all applied inverse methods, whereby sLORETA and LCMV were equally accurate. SIGNIFICANCE Our results offer guidance in selecting inverse methods and IED phases for hd-ESI, compare the performance of hd-ESI and 18FDG-PET and encourage future studies in investigating the relationship between interictal ESI and 18FDG-PET hypometabolism.
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Affiliation(s)
- Daniel van de Velden
- University Medical Center Göttingen, Clinic for Neurology, 37075 Göttingen, Germany.
| | - Ev-Christin Heide
- University Medical Center Göttingen, Clinic for Neurology, 37075 Göttingen, Germany
| | - Caroline Bouter
- University Medical Center Göttingen, Department of Nuclear Medicine, 37075 Göttingen, Germany
| | - Jan Bucerius
- University Medical Center Göttingen, Department of Nuclear Medicine, 37075 Göttingen, Germany
| | - Christian H Riedel
- University Medical Center Göttingen, Institute for Diagnostic and Interventional Neuroradiology, 37075 Göttingen, Germany
| | - Niels K Focke
- University Medical Center Göttingen, Clinic for Neurology, 37075 Göttingen, Germany.
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Prentice A, Barreiros AR, van der Vinne N, Stuiver S, van Dijk H, van Waarde JA, Korgaonkar M, Sack AT, Arns M. Rostral Anterior Cingulate Cortex Oscillatory Power Indexes Treatment-Resistance to Multiple Therapies in Major Depressive Disorder. Neuropsychobiology 2023; 82:373-383. [PMID: 37848013 DOI: 10.1159/000533853] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 08/22/2023] [Indexed: 10/19/2023]
Abstract
INTRODUCTION High rostral anterior cingulate cortex (rACC) activity is proposed as a nonspecific prognostic marker for treatment response in major depressive disorder, independent of treatment modality. However, other studies report a negative association between baseline high rACC activation and treatment response. Interestingly, these contradictory findings were also found when focusing on oscillatory markers, specifically rACC-theta power. An explanation could be that rACC-theta activity dynamically changes according to number of previous treatment attempts and thus is mediated by level of treatment-resistance. METHODS Primarily, we analyzed differences in rACC- and frontal-theta activity in large national cross-sectional samples representing various levels of treatment-resistance and resistance to multimodal treatments in depressed patients (psychotherapy [n = 175], antidepressant medication [AD; n = 106], repetitive transcranial magnetic stimulation [rTMS; n = 196], and electroconvulsive therapy [ECT; n = 41]), and the respective difference between remitters and non-remitters. For exploratory purposes, we also investigated other frequency bands (delta, alpha, beta, gamma). RESULTS rACC-theta activity was higher (p < 0.001) in the more resistant rTMS and ECT patients relative to the less resistant psychotherapy and AD patients (psychotherapy-rTMS: d = 0.315; AD-rTMS: d = 0.320; psychotherapy-ECT: d = 1.031; AD-ECT: d = 1.034), with no difference between psychotherapy and AD patients. This association was even more pronounced after controlling for frontal-theta. Post hoc analyses also yielded effects for delta, beta, and gamma bands. CONCLUSION Our findings suggest that by factoring in degree of treatment-resistance during interpretation of the rACC-theta biomarker, its usefulness in treatment selection and prognosis could potentially be improved substantially in future real-world practice. Future research should however also investigate specificity of the theta band.
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Affiliation(s)
- Amourie Prentice
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands,
- Research Institute Brainclinics, Brainclinics Foundation, Nijmegen, The Netherlands,
- Synaeda Research, Synaeda Psycho Medisch Centrum, Drachten, The Netherlands,
| | - Ana Rita Barreiros
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
- Brain Dynamics Centre, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
| | - Nikita van der Vinne
- Research Institute Brainclinics, Brainclinics Foundation, Nijmegen, The Netherlands
- Synaeda Research, Synaeda Psycho Medisch Centrum, Drachten, The Netherlands
| | - Sven Stuiver
- Department of Psychiatry, Rijnstate Depression Centre, Arnhem, The Netherlands
- Technical Medical Centre, University of Twente, Enschede, The Netherlands
| | - Hanneke van Dijk
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Research Institute Brainclinics, Brainclinics Foundation, Nijmegen, The Netherlands
| | | | - Mayuresh Korgaonkar
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
- Brain Dynamics Centre, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Martijn Arns
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Research Institute Brainclinics, Brainclinics Foundation, Nijmegen, The Netherlands
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Heide E, van de Velden D, Garnica Agudelo D, Hewitt M, Riedel C, Focke NK. Feasibility of high-density electric source imaging in the presurgical workflow: Effect of number of spikes and automated spike detection. Epilepsia Open 2023; 8:785-796. [PMID: 36938790 PMCID: PMC10472417 DOI: 10.1002/epi4.12732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 03/16/2023] [Indexed: 03/21/2023] Open
Abstract
OBJECTIVE Presurgical high-density electric source imaging (hdESI) of interictal epileptic discharges (IEDs) is only used by few epilepsy centers. One obstacle is the time-consuming workflow both for recording as well as for visual review. Therefore, we analyzed the effect of (a) an automated IED detection and (b) the number of IEDs on the accuracy of hdESI and time-effectiveness. METHODS In 22 patients with pharmacoresistant focal epilepsy receiving epilepsy surgery (Engel 1) we retrospectively detected IEDs both visually and semi-automatically using the EEG analysis software Persyst in 256-channel EEGs. The amount of IEDs, the Euclidean distance between hdESI maximum and resection zone, and the operator time were compared. Additionally, we evaluated the intra-individual effect of IED quantity on the distance between hdESI maximum of all IEDs and hdESI maximum when only a reduced amount of IEDs were included. RESULTS There was no significant difference in the number of IEDs between visually versus semi-automatically marked IEDs (74 ± 56 IEDs/patient vs 116 ± 115 IEDs/patient). The detection method of the IEDs had no significant effect on the mean distances between resection zone and hdESI maximum (visual: 26.07 ± 31.12 mm vs semi-automated: 33.6 ± 34.75 mm). However, the mean time needed to review the full datasets semi-automatically was shorter by 275 ± 46 min (305 ± 72 min vs 30 ± 26 min, P < 0.001). The distance between hdESI of the full versus reduced amount of IEDs of the same patient was smaller than 1 cm when at least a mean of 33 IEDs were analyzed. There was a significantly shorter intraindividual distance between resection zone and hdESI maximum when 30 IEDs were analyzed as compared to the analysis of only 10 IEDs (P < 0.001). SIGNIFICANCE Semi-automatized processing and limiting the amount of IEDs analyzed (~30-40 IEDs per cluster) appear to be time-saving clinical tools to increase the practicability of hdESI in the presurgical work-up.
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Affiliation(s)
- Ev‐Christin Heide
- Department of NeurologyUniversity Medical Center, Georg‐August UniversityGöttingenGermany
| | - Daniel van de Velden
- Department of NeurologyUniversity Medical Center, Georg‐August UniversityGöttingenGermany
| | - David Garnica Agudelo
- Department of NeurologyUniversity Medical Center, Georg‐August UniversityGöttingenGermany
| | - Manuel Hewitt
- Department of NeurologyUniversity Medical Center, Georg‐August UniversityGöttingenGermany
| | - Christian Riedel
- Institute for Diagnostic and Interventional NeuroradiologyUniversity Medical Center, Georg‐August UniversityGöttingenGermany
| | - Niels K. Focke
- Department of NeurologyUniversity Medical Center, Georg‐August UniversityGöttingenGermany
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Miron G, Baag T, Götz K, Holtkamp M, Vorderwülbecke BJ. Integration of interictal EEG source localization in presurgical epilepsy evaluation - A single-center prospective study. Epilepsia Open 2023; 8:877-887. [PMID: 37170682 PMCID: PMC10472400 DOI: 10.1002/epi4.12754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/27/2023] [Indexed: 05/13/2023] Open
Abstract
OBJECTIVE To investigate cost in working hours for initial integration of interictal EEG source localization (ESL) into clinical practice of a tertiary epilepsy center, and to examine concordance of results obtained with three different ESL pipelines. METHODS This prospective study covered the first year of using ESL in the Epilepsy-Center Berlin-Brandenburg. Patients aged ≥14 years with drug-resistant focal epilepsy referred for noninvasive presurgical evaluation were included. Interictal ESL was based on low-density EEG and individual head models. Source maxima were obtained from two freely available software packages and one commercial provider. One physician and computer scientist documented their working hours for setting up and processing ESL. Additionally, a survey was conducted among epilepsy centers in Germany to assess the current role of ESL in presurgical evaluation. RESULTS Of 40 patients included, 22 (55%) had enough interictal spikes for ESL. The physician's working times decreased from median 4.7 hours [interquartile range 3.9-6.4] in the first third of cases to 2.0 hours [1.9-2.4] in the remaining two thirds; P < 0.01. In addition, computer scientist and physician spent a total of 35.5 and 33.0 working hours on setting up the digital infrastructure, and on training and testing. Sublobar agreement between all three pipelines was 20%, mean measurement of agreement (kappa) 0.13. Finally, the survey revealed that 53% of epilepsy centers in Germany currently use ESL for presurgical evaluation. SIGNIFICANCE This study provides information regarding expected effort and costs for integration of ESL into an epilepsy surgery program. Low result agreement across different ESL pipelines calls for further standardization.
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Affiliation(s)
- Gadi Miron
- Epilepsy‐Center Berlin‐BrandenburgInstitute for Diagnostics of EpilepsyBerlinGermany
- Department of Neurology, Epilepsy‐Center Berlin‐BrandenburgCharité – Universitätsmedizin BerlinBerlinGermany
| | - Thomas Baag
- Epilepsy‐Center Berlin‐BrandenburgInstitute for Diagnostics of EpilepsyBerlinGermany
| | - Kara Götz
- Epilepsy‐Center Berlin‐BrandenburgInstitute for Diagnostics of EpilepsyBerlinGermany
- Department of Neurology, Epilepsy‐Center Berlin‐BrandenburgCharité – Universitätsmedizin BerlinBerlinGermany
| | - Martin Holtkamp
- Epilepsy‐Center Berlin‐BrandenburgInstitute for Diagnostics of EpilepsyBerlinGermany
- Department of Neurology, Epilepsy‐Center Berlin‐BrandenburgCharité – Universitätsmedizin BerlinBerlinGermany
| | - Bernd J. Vorderwülbecke
- Epilepsy‐Center Berlin‐BrandenburgInstitute for Diagnostics of EpilepsyBerlinGermany
- Department of Neurology, Epilepsy‐Center Berlin‐BrandenburgCharité – Universitätsmedizin BerlinBerlinGermany
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Marchesotti S, Bernasconi F, Rognini G, De Lucia M, Bleuler H, Blanke O. Neural signatures of visuo-motor integration during human-robot interactions. Front Neurorobot 2023; 16:1034615. [PMID: 36776553 PMCID: PMC9908758 DOI: 10.3389/fnbot.2022.1034615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/23/2022] [Indexed: 01/28/2023] Open
Abstract
Visuo-motor integration shapes our daily experience and underpins the sense of feeling in control over our actions. The last decade has seen a surge in robotically and virtually mediated interactions, whereby bodily actions ultimately result in an artificial movement. But despite the growing number of applications, the neurophysiological correlates of visuo-motor processing during human-machine interactions under dynamic conditions remain scarce. Here we address this issue by employing a bimanual robotic interface able to track voluntary hands movement, rendered in real-time into the motion of two virtual hands. We experimentally manipulated the visual feedback in the virtual reality with spatial and temporal conflicts and investigated their impact on (1) visuo-motor integration and (2) the subjective experience of being the author of one's action (i.e., sense of agency). Using somatosensory evoked responses measured with electroencephalography, we investigated neural differences occurring when the integration between motor commands and visual feedback is disrupted. Our results show that the right posterior parietal cortex encodes for differences between congruent and spatially-incongruent interactions. The experimental manipulations also induced a decrease in the sense of agency over the robotically-mediated actions. These findings offer solid neurophysiological grounds that can be used in the future to monitor integration mechanisms during movements and ultimately enhance subjective experience during human-machine interactions.
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Affiliation(s)
- Silvia Marchesotti
- Laboratory of Cognitive Neuroscience, Center for Neuroprosthetics and Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland,Laboratory of Robotic Systems, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland,*Correspondence: Silvia Marchesotti
| | - Fosco Bernasconi
- Laboratory of Cognitive Neuroscience, Center for Neuroprosthetics and Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Giulio Rognini
- Laboratory of Cognitive Neuroscience, Center for Neuroprosthetics and Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland,Laboratory of Robotic Systems, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Marzia De Lucia
- Laboratoire de Recherche en Neuroimagerie, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Hannes Bleuler
- Laboratory of Robotic Systems, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Olaf Blanke
- Laboratory of Cognitive Neuroscience, Center for Neuroprosthetics and Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland,Department of Clinical Neurosciences, Faculty of Medicine, University Hospital, Geneva, Switzerland,Olaf Blanke
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