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Lefaucheur JP, Nguyen JP, Delmas A, Croci S, Bredoux L, Hodaj H. Targeting Lower Limb, Upper Limb, and Face Representation in the Primary Motor Cortex for the Practice of Neuronavigated Transcranial Magnetic Stimulation. Neuromodulation 2024; 27:572-583. [PMID: 37212759 DOI: 10.1016/j.neurom.2023.04.470] [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: 01/04/2023] [Revised: 03/28/2023] [Accepted: 04/13/2023] [Indexed: 05/23/2023]
Abstract
OBJECTIVE The primary motor cortex (M1) is a usual target for therapeutic application of repetitive transcranial magnetic stimulation (rTMS), especially the region of hand motor representation. However, other M1 regions can be considered as potential rTMS targets, such as the region of lower limb or face representation. In this study, we assessed the localization of all these regions on magnetic resonance imaging (MRI) with the aim of defining three standardized M1 targets for the practice of neuronavigated rTMS. MATERIALS AND METHODS A pointing task of these targets was performed by three rTMS experts on 44 healthy brain MRI data to assess interrater reliability (including the calculation of intraclass correlation coefficients [ICCs] and coefficients of variation [CoVs] and the construction of Bland-Altman plots). In addition, two "standard" brain MRI data were randomly interspersed with the other MRI data to assess intrarater reliability. A barycenter was calculated for each target (with x-y-z coordinates provided in normalized brain coordinate systems), in addition to the geodesic distance between the scalp projection of the barycenters of these different targets. RESULTS Intrarater and interrater agreement was good, according to ICCs, CoVs, or Bland-Altman plots, although interrater variability was greater for anteroposterior (y) and craniocaudal (z) coordinates, especially for the face target. The scalp projection of the barycenters between the different cortical targets ranged from 32.4 to 35.5 mm for either the lower-limb-to-upper-limb target distance or the upper-limb-to-face target distance. CONCLUSIONS This work clearly delineates three different targets for the application of motor cortex rTMS that correspond to lower limb, upper limb, and face motor representations. These three targets are sufficiently spaced to consider that their stimulation can act on distinct neural networks.
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Affiliation(s)
- Jean-Pascal Lefaucheur
- Clinical Neurophysiology Department, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (AP-HP), Créteil, France; ENT team (UR/EA-4391), Faculty of Health, Paris Est Créteil University, Créteil, France.
| | | | | | | | | | - Hasan Hodaj
- Pain Center, Anesthesiology-Critical Care Department, Grenoble Alpes University Hospital, Grenoble, France; Inserm U1216, Grenoble Institute of Neurosciences, Grenoble Alpes University, Grenoble, France
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Lefaucheur JP. It is time to personalize rTMS targeting for the treatment of pain. Neurophysiol Clin 2024; 54:102950. [PMID: 38382139 DOI: 10.1016/j.neucli.2024.102950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 02/23/2024] Open
Affiliation(s)
- Jean-Pascal Lefaucheur
- Unité de Neurophysiologie Clinique, Hôpital Henri Mondor, AP-HP, Créteil, France; UR ENT (EA4391), Faculté de Santé, Université Paris Est Créteil, Créteil, France.
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Prei K, Kanig C, Osnabruegge M, Langguth B, Mack W, Abdelnaim M, Schecklmann M, Schoisswohl S. Limited evidence for reliability of low and high frequency rTMS over the motor cortex. Brain Res 2023; 1820:148534. [PMID: 37586677 DOI: 10.1016/j.brainres.2023.148534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/07/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
OBJECTIVE The aim of this study was to investigate the reliability of low-frequency and high-frequency repetitive transcranial magnetic stimulation (rTMS) on healthy individuals over the motor cortex. A secondary outcome was the assessment if low-frequency rTMS results in inhibition and high-frequency rTMS results in facilitation. METHODS In this experiment, 30 healthy participants received on four consecutive days one session each with application of 1 Hz or 20 Hz rTMS over the left motor cortex. 1 Hz and 20 Hz were applied in alternating order, whereby the starting frequency was randomized. Motor evoked potentials (MEPs) were measured before and after each session. Reliability measures were intraclass and Pearson's correlation coefficient (ICC and r). RESULTS ICCs and r values were low to moderate. Notably, within subgroups of less confounded measures, we found good r values for 20 Hz rTMS. The group-level analysis did not demonstrate a clear low-frequency inhibition and high-frequency facilitation pattern. At the single-subject level, only one participant exhibited significant changes consistent with the expected pattern, with concurrent decreases in MEPs following 1 Hz sessions and increases following 20 Hz sessions. CONCLUSION The investigated neuromodulatory protocols show low to moderate reliability. Results are questioning the low-frequency inhibition and high-frequency facilitation pattern. SIGNIFICANCE Methodological improvements for the usage of rTMS are necessary to increase validity and reliability of non-invasive brain stimulation.
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Affiliation(s)
- Kilian Prei
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany
| | - Carolina Kanig
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany; Department of Human Sciences, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany.
| | - Mirja Osnabruegge
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany; Department of Human Sciences, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany
| | - Berthold Langguth
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany
| | - Wolfgang Mack
- Department of Human Sciences, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany
| | - Mohamed Abdelnaim
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany
| | - Martin Schecklmann
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany
| | - Stefan Schoisswohl
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany; Department of Human Sciences, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany
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Nguyen DTA, Julkunen P, Säisänen L, Määttä S, Rissanen SM, Lintu N, Könönen M, Lakka T, Karjalainen PA. Developmental models of motor-evoked potential features by transcranial magnetic stimulation across age groups from childhood to adulthood. Sci Rep 2023; 13:10604. [PMID: 37391521 PMCID: PMC10313665 DOI: 10.1038/s41598-023-37775-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 06/27/2023] [Indexed: 07/02/2023] Open
Abstract
To derive the maturation of neurophysiological processes from childhood to adulthood reflected by the change of motor-evoked potential (MEP) features. 38 participants were recruited from four groups (age mean in years [SD in months], number (males)): children (7.3 [4.2], 7(4)), preadolescents (10.3 [6.9], 10(5)), adolescents (15.3 [9.8], 11(5)), and adults (26.9 [46.2], 10(5)). The navigated transcranial magnetic stimulation was performed on both hemispheres at seven stimulation intensity (SI) levels from sub- to supra-threshold and targeted to the representative cortical area of abductor pollicis brevis muscle. MEPs were measured from three hand- and two forearm-muscles. The input-output (I/O) curves of MEP features across age groups were constructed using linear mixed-effect models. Age and SI significantly affected MEP features, whereas the stimulated side had a minor impact. MEP size and duration increased from childhood to adulthood. MEP onset- and peak-latency dropped in adolescence, particularly in hand muscles. Children had the smallest MEPs with the highest polyphasia, whereas I/O curves were similar among preadolescents, adolescents, and adults. This study illustrates some of the changing patterns of MEP features across the ages, suggesting developing patterns of neurophysiological processes activated by TMS, and to motivate studies with larger sample size.
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Affiliation(s)
- Dao T A Nguyen
- Department of Technical Physics, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland.
| | - Petro Julkunen
- Department of Technical Physics, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland
- Department of Clinical Neurophysiology, Kuopio University Hospital, POB 100, 70029 KYS, Kuopio, Finland
| | - Laura Säisänen
- Department of Technical Physics, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland
- Department of Clinical Neurophysiology, Kuopio University Hospital, POB 100, 70029 KYS, Kuopio, Finland
| | - Sara Määttä
- Department of Clinical Neurophysiology, Kuopio University Hospital, POB 100, 70029 KYS, Kuopio, Finland
| | - Saara M Rissanen
- Department of Technical Physics, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland
| | - Niina Lintu
- Institute of Biomedicine, University of Eastern Finland, POB 162, 70211, Kuopio, Finland
| | - Mervi Könönen
- Department of Technical Physics, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland
| | - Timo Lakka
- Institute of Biomedicine, University of Eastern Finland, POB 162, 70211, Kuopio, Finland
- Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, POB 100, 70029 KYS, Kuopio, Finland
- Foundation for Research in Health Exercise and Nutrition, Kuopio Research Institute of Exercise Medicine, Haapaniementie 16, 70100, Kuopio, Finland
| | - Pasi A Karjalainen
- Department of Technical Physics, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland
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Barbi C, Vernillo G, Emadi Andani M, Giuriato G, Laginestra FG, Cavicchia A, Fiorini Aloisi G, Martignon C, Pedrinolla A, Schena F, Venturelli M. Comparison between conventional and neuronavigated strategies to assess corticospinal responsiveness in unfatigued and fatigued knee-extensor muscles. Neurosci Lett 2023:137351. [PMID: 37321388 DOI: 10.1016/j.neulet.2023.137351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 05/27/2023] [Accepted: 06/12/2023] [Indexed: 06/17/2023]
Abstract
In studying neuromuscular fatigability, researchers commonly use functional criteria to position and hold the transcranial magnetic stimulation (TMS) coil during testing sessions. This could influence the magnitude of corticospinal excitability and inhibition responses due to imprecise and unsteady positions of the coil. To reduce coil position and orientation variability, neuronavigated TMS (nTMS) could be used. We evaluated the accuracy of nTMS and a standardized function-guided procedure for maintaining TMS coil position both in unfatigued and fatigued knee extensors. Eighteen participants (10F/8M) volunteered in two identical and randomized sessions. Maximal and submaximal neuromuscular evaluations were performed with TMS three times before (PRE_1) and three times after (PRE_2) a 2 min resting session and one time immediately after (POST) a 2-min sustained maximal voluntary isometric contraction (MVIC). The located "hotspot" [the location that evoked the largest motor-evoked potential (MEP) responses in the rectus femoris] was maintained either with or without nTMS. MEP, silent period (SP) and the distance between the "hotspot" and the actual coil position were recorded. A time × contraction intensity × testing session × muscle interaction was not observed for MEP, SP, and distance. Bland-Altman plots presented adequate agreements for MEP and SP. Spatial accuracy of TMS coil position over the motor cortex did not influence corticospinal excitability and inhibition in unfatigued and fatigued knee extensors. The variability in MEP and SP responses may be due to spontaneous fluctuations in corticospinal excitability and inhibition, and it is not altered by the spatial stability of the stimulation point.
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Affiliation(s)
- C Barbi
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - G Vernillo
- Department of Biomedical Sciences for Health, University of Milan, Italy
| | - M Emadi Andani
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - G Giuriato
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - F G Laginestra
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - A Cavicchia
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - G Fiorini Aloisi
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - C Martignon
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - A Pedrinolla
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - F Schena
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy
| | - M Venturelli
- Department of Neuroscience, Biomedicine, and Movement, University of Verona, Italy.
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Selective Stimulus Intensity during Hotspot Search Ensures Faster and More Accurate Preoperative Motor Mapping with nTMS. Brain Sci 2023; 13:brainsci13020285. [PMID: 36831828 PMCID: PMC9954713 DOI: 10.3390/brainsci13020285] [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: 01/03/2023] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
INTRODUCTION Navigated transcranial magnetic stimulation (nTMS) has emerged as one of the most innovative techniques in neurosurgical practice. However, nTMS motor mapping involves rigorous steps, and the importance of an accurate execution method has not been emphasized enough. In particular, despite strict adherence to procedural protocols, we have observed high variability in map activation according to the choice of stimulation intensity (SI) right from the early stage of hotspot localization. We present a retrospective analysis of motor mappings performed between March 2020 and July 2022, where the SI was only chosen with rigorous care in the most recent ones, under the guide of an expert neurophysiologist. MATERIALS AND METHODS In order to test the ability to reduce inaccurate responses and time expenditure using selective SI, data were collected from 16 patients who underwent mapping with the random method (group A) and 15 patients who underwent mapping with the proposed method (group B). The parameters considered were resting motor threshold (%), number of stimuli, number of valid motor evoked potentials (MEPs), number of valid MEPs considered true positives (TPs), number of valid MEPs considered false positives (FPs), ratio of true-positive MEPs to total stimuli, ratio of true-positive MEPs to valid MEPs, minimum amplitude, maximum amplitude and mapping time for each patient. RESULTS The analysis showed statistically significant reductions in total stimulus demand, procedural time and number of false-positive MEPs. Significant increases were observed in the number of true-positive MEPs, the ratio of true-positive MEPs to total stimuli and the ratio of true-positive MEPs to valid MEPs. In the subgroups analyzed, there were similar trends, in particular, an increase in true positives and a decrease in false-positive responses. CONCLUSIONS The precise selection of SI during hotspot search in nTMS motor mapping could provide reliable cortical maps in short time and with low employment of resources. This method seems to ensure that a MEP really represents a functionally eloquent cortical point, making mapping more intuitive even in less experienced centers.
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Šoda J, Pavelin S, Vujović I, Rogić Vidaković M. Assessment of Motor Evoked Potentials in Multiple Sclerosis. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23010497. [PMID: 36617096 PMCID: PMC9824873 DOI: 10.3390/s23010497] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 06/01/2023]
Abstract
Transcranial magnetic stimulation (TMS) is a noninvasive technique mainly used for the assessment of corticospinal tract integrity and excitability of the primary motor cortices. Motor evoked potentials (MEPs) play a pivotal role in TMS studies. TMS clinical guidelines, concerning the use and interpretation of MEPs in diagnosing and monitoring corticospinal tract integrity in people with multiple sclerosis (pwMS), were established almost ten years ago and refer mainly to the use of TMS implementation; this comprises the magnetic stimulator connected to a standard EMG unit, with the positioning of the coil performed by using the external landmarks on the head. The aim of the present work was to conduct a narrative literature review on the MEP assessment and outcome measures in clinical and research settings, assessed by TMS Methodological characteristics of different TMS system implementations (TMS without navigation, line-navigated TMS and e-field-navigated TMS); these were discussed in the context of mapping the corticospinal tract integrity in MS. An MEP assessment of two case reports, by using an e-field-navigated TMS, was presented; the results of the correspondence between the e-field-navigated TMS with MRI, and the EDSS classifications were presented. Practical and technical guiding principles for the improvement of TMS studies in MEP assessment for MS are discussed, suggesting the use of e-field TMS assessment in the sense that it can improve the accuracy of corticospinal tract integrity testing by providing a more objective correspondence of the neurophysiological (e-field-navigated TMS) and clinical (Expanded Disability Status Scale-EDSS) classifications.
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Affiliation(s)
- Joško Šoda
- Signal Processing, Analysis, and Advanced Diagnostics Research and Education Laboratory (SPAADREL), Faculty of Maritime Studies, University of Split, 21000 Split, Croatia
| | - Sanda Pavelin
- Department of Neurology, University Hospital of Split, 21000 Split, Croatia
| | - Igor Vujović
- Signal Processing, Analysis, and Advanced Diagnostics Research and Education Laboratory (SPAADREL), Faculty of Maritime Studies, University of Split, 21000 Split, Croatia
| | - Maja Rogić Vidaković
- Laboratory for Human and Experimental Neurophysiology, Department of Neuroscience, School of Medicine, University of Split, 21000 Split, Croatia
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Nieminen AE, Nieminen JO, Stenroos M, Novikov P, Nazarova M, Vaalto S, Nikulin V, Ilmoniemi RJ. Accuracy and precision of navigated transcranial magnetic stimulation. J Neural Eng 2022; 19. [PMID: 36541458 DOI: 10.1088/1741-2552/aca71a] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022]
Abstract
Objective.Transcranial magnetic stimulation (TMS) induces an electric field (E-field) in the cortex. To facilitate stimulation targeting, image-guided neuronavigation systems have been introduced. Such systems track the placement of the coil with respect to the head and visualize the estimated cortical stimulation location on an anatomical brain image in real time. The accuracy and precision of the neuronavigation is affected by multiple factors. Our aim was to analyze how different factors in TMS neuronavigation affect the accuracy and precision of the coil-head coregistration and the estimated E-field.Approach.By performing simulations, we estimated navigation errors due to distortions in magnetic resonance images (MRIs), head-to-MRI registration (landmark- and surface-based registrations), localization and movement of the head tracker, and localization of the coil tracker. We analyzed the effect of these errors on coil and head coregistration and on the induced E-field as determined with simplistic and realistic head models.Main results.Average total coregistration accuracies were in the range of 2.2-3.6 mm and 1°; precision values were about half of the accuracy values. The coregistration errors were mainly due to head-to-MRI registration with average accuracies 1.5-1.9 mm/0.2-0.4° and precisions 0.5-0.8 mm/0.1-0.2° better with surface-based registration. The other major source of error was the movement of the head tracker with average accuracy of 1.5 mm and precision of 1.1 mm. When assessed within an E-field method, the average accuracies of the peak E-field location, orientation, and magnitude ranged between 1.5 and 5.0 mm, 0.9 and 4.8°, and 4.4 and 8.5% across the E-field models studied. The largest errors were obtained with the landmark-based registration. When computing another accuracy measure with the most realistic E-field model as a reference, the accuracies tended to improve from about 10 mm/15°/25% to about 2 mm/2°/5% when increasing realism of the E-field model.Significance.The results of this comprehensive analysis help TMS operators to recognize the main sources of error in TMS navigation and that the coregistration errors and their effect in the E-field estimation depend on the methods applied. To ensure reliable TMS navigation, we recommend surface-based head-to-MRI registration and realistic models for E-field computations.
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Affiliation(s)
- Aino E Nieminen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland.,AMI Centre, Aalto NeuroImaging, Aalto University School of Science, Espoo, Finland
| | - Jaakko O Nieminen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Matti Stenroos
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Pavel Novikov
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland.,Centre for Cognition and Decision Making, Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
| | - Maria Nazarova
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland.,Centre for Cognition and Decision Making, Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States of America
| | - Selja Vaalto
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland.,HUS Diagnostic Center, Clinical Neurophysiology, Clinical Neurosciences, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Vadim Nikulin
- Centre for Cognition and Decision Making, Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia.,Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Risto J Ilmoniemi
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
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Roumengous T, Reutter AB, Peterson CL. Effect of low-cost transcranial magnetic stimulation navigation on hotspot targeting and motor evoked potential variability in the biceps brachii. Restor Neurol Neurosci 2021; 39:319-328. [PMID: 34657854 DOI: 10.3233/rnn-211207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) can monitor or modulate brain excitability. However, reliability of TMS outcomes depends on consistent coil placement during stimulation. Neuronavigated TMS systems can address this issue, but their cost limits their use outside of specialist research environments. OBJECTIVE The objective was to evaluate the performance of a low-cost navigated TMS approach in improving coil placement consistency and its effect on motor evoked potentials (MEPs) when targeting the biceps brachii at rest and during voluntary contractions. METHODS We implemented a navigated TMS system using a low-cost 3D camera system and open-source software environment programmed using the Unity 3D engine. MEPs were collected from the biceps brachii at rest and during voluntary contractions across two sessions in ten non-disabled individuals. Motor hotspots were recorded and targeted via two conditions: navigated and conventional. RESULTS The low-cost navigated TMS system reduced coil orientation error (pitch: 1.18°±1.2°, yaw: 1.99°±1.9°, roll: 1.18°±2.2° with navigation, versus pitch: 3.7°±5.7°, yaw: 3.11°±3.1°, roll: 3.8°±9.1° with conventional). The improvement in coil orientation had no effect on MEP amplitudes and variability. CONCLUSIONS The low-cost system is a suitable alternative to expensive systems in tracking the motor hotspot between sessions and quantifying the error in coil placement when delivering TMS. Biceps MEP variability reflects physiological variability across a range of voluntary efforts, that can be captured equally well with navigated or conventional approaches of coil locating.
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Affiliation(s)
- Thibault Roumengous
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Alec B Reutter
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Carrie L Peterson
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
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Vasilyev AN, Nuzhdin YO, Kaplan AY. Does Real-Time Feedback Affect Sensorimotor EEG Patterns in Routine Motor Imagery Practice? Brain Sci 2021; 11:brainsci11091234. [PMID: 34573253 PMCID: PMC8469546 DOI: 10.3390/brainsci11091234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/16/2021] [Accepted: 09/16/2021] [Indexed: 11/23/2022] Open
Abstract
Background. Motor imagery engages much of the same neural circuits as an overt movement. Therefore, the mental rehearsal of movements is often used to supplement physical training and might aid motor neurorehabilitation after stroke. One attempt to capture the brain’s involvement in imagery involves the use, as a marker, of the depression or event-related desynchronization (ERD) of thalamocortical sensorimotor rhythms found in a human electroencephalogram (EEG). Using fast real-time processing, it is possible to make the subject aware of their own brain reactions or—even better—to turn them into actions through a technology called the brain–computer interface (BCI). However, it remains unclear whether BCI-enabled imagery facilitates a stronger or qualitatively different brain response compared to the open-loop training. Methods. Seven healthy volunteers who were experienced in both closed and open-loop motor imagery took part in six experimental sessions over a period of 4.5 months, in which they performed kinesthetic imagery of a previously known set of finger and arm movements with simultaneous 30-channel EEG acquisition. The first and the last session mostly consisted of feedback trials in which the subjects were presented with the classification results of the EEG patterns in real time; during the other sessions, no feedback was provided. Spatiotemporal and amplitude features of the ERD patterns concomitant with imagery were compared across experimental days and between feedback conditions using linear mixed-effects modeling. Results. The main spatial sources of ERD appeared to be highly stable across the six experimental days, remaining nearly identical in five of seven subjects (Pearson’s ρ > 0.94). Only in one subject did the spatial pattern of activation statistically significantly differ (p = 0.009) between the feedback and no-feedback conditions. Real-time visual feedback delivered through the BCI did not significantly increase the ERD strength. Conclusion. The results imply that the potential benefits of MI could be yielded by well-habituated subjects with a simplified open-loop setup, e.g., through at-home self-practice.
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Affiliation(s)
- Anatoly N. Vasilyev
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia; (Y.O.N.); (A.Y.K.)
- MEG Center, Moscow State University of Psychology and Education, 123290 Moscow, Russia
- Correspondence:
| | - Yury O. Nuzhdin
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia; (Y.O.N.); (A.Y.K.)
| | - Alexander Y. Kaplan
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia; (Y.O.N.); (A.Y.K.)
- Center for Neurotechnology and Machine Learning, Immanuel Kant Baltic Federal University, 236016 Kaliningrad, Russia
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11
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Sondergaard RE, Martino D, Kiss ZHT, Condliffe EG. TMS Motor Mapping Methodology and Reliability: A Structured Review. Front Neurosci 2021; 15:709368. [PMID: 34489629 PMCID: PMC8417420 DOI: 10.3389/fnins.2021.709368] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/13/2021] [Indexed: 11/29/2022] Open
Abstract
Motor cortical representation can be probed non-invasively using a transcranial magnetic stimulation (TMS) technique known as motor mapping. The mapping technique can influence features of the maps because of several controllable elements. Here we review the literature on six key motor mapping parameters, as well as their influence on outcome measures and discuss factors impacting their selection. 132 of 1,587 distinct records were examined in detail and synthesized to form the basis of our review. A summary of mapping parameters, their impact on outcome measures and feasibility considerations are reported to support the design and interpretation of TMS mapping studies.
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Affiliation(s)
- Rachel E. Sondergaard
- Department of Clinical Neuroscience, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Davide Martino
- Department of Clinical Neuroscience, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Zelma H. T. Kiss
- Department of Clinical Neuroscience, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Psychiatry, University of Calgary, Calgary, AB, Canada
| | - Elizabeth G. Condliffe
- Department of Clinical Neuroscience, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
- Department of Pediatrics, University of Calgary, Calgary, AB, Canada
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12
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Sollmann N, Krieg SM, Säisänen L, Julkunen P. Mapping of Motor Function with Neuronavigated Transcranial Magnetic Stimulation: A Review on Clinical Application in Brain Tumors and Methods for Ensuring Feasible Accuracy. Brain Sci 2021; 11:brainsci11070897. [PMID: 34356131 PMCID: PMC8305823 DOI: 10.3390/brainsci11070897] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/29/2021] [Accepted: 07/02/2021] [Indexed: 12/15/2022] Open
Abstract
Navigated transcranial magnetic stimulation (nTMS) has developed into a reliable non-invasive clinical and scientific tool over the past decade. Specifically, it has undergone several validating clinical trials that demonstrated high agreement with intraoperative direct electrical stimulation (DES), which paved the way for increasing application for the purpose of motor mapping in patients harboring motor-eloquent intracranial neoplasms. Based on this clinical use case of the technique, in this article we review the evidence for the feasibility of motor mapping and derived models (risk stratification and prediction, nTMS-based fiber tracking, improvement of clinical outcome, and assessment of functional plasticity), and provide collected sets of evidence for the applicability of quantitative mapping with nTMS. In addition, we provide evidence-based demonstrations on factors that ensure methodological feasibility and accuracy of the motor mapping procedure. We demonstrate that selection of the stimulation intensity (SI) for nTMS and spatial density of stimuli are crucial factors for applying motor mapping accurately, while also demonstrating the effect on the motor maps. We conclude that while the application of nTMS motor mapping has been impressively spread over the past decade, there are still variations in the applied protocols and parameters, which could be optimized for the purpose of reliable quantitative mapping.
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Affiliation(s)
- Nico Sollmann
- Department of Diagnostic and Interventional Radiology, University Hospital Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675 Munich, Germany
- TUM-Neuroimaging Center, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany;
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, San Francisco, CA 94143, USA
- Correspondence:
| | - Sandro M. Krieg
- TUM-Neuroimaging Center, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany;
- Department of Neurosurgery, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675 Munich, Germany
| | - Laura Säisänen
- Department of Clinical Neurophysiology, Kuopio University Hospital, 70029 Kuopio, Finland; (L.S.); (P.J.)
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
| | - Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, 70029 Kuopio, Finland; (L.S.); (P.J.)
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
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13
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Fleischmann R, Triller P, Brandt SA, Schmidt SH. Human Premotor Corticospinal Projections Are Engaged in Motor Preparation at Discrete Time Intervals: A TMS-Induced Virtual Lesion Study. FRONTIERS IN NEUROERGONOMICS 2021; 2:678906. [PMID: 38235216 PMCID: PMC10790911 DOI: 10.3389/fnrgo.2021.678906] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/26/2021] [Indexed: 01/19/2024]
Abstract
Objectives: The significance of pre-motor (PMC) corticospinal projections in a frontoparietal motor network remains elusive. Temporal activation patterns can provide valuable information about a region's engagement in a hierarchical network. Navigated transcranial magnetic stimulation (nTMS)-induced virtual lesions provide an excellent method to study cortical physiology by disrupting ongoing activity at high temporal resolution and anatomical precision. We use nTMS-induced virtual lesions applied during an established behavioral task demanding pre-motor activation to clarify the temporal activation pattern of pre-motor corticospinal projections. Materials and Methods: Ten healthy volunteers participated in the experiment (4 female, mean age 24 ± 2 years, 1 left-handed). NTMS was used to map Brodmann areae 4 and 6 for primary motor (M1) and PMC corticospinal projections. We then determined the stimulator output intensity required to elicit a 1 mV motor evoked potential (1 mV-MT) through M1 nTMS. TMS pulse were randomly delivered at distinct time intervals (40, 60, 80, 100, 120, and 140 ms) at 1 mV-MT intensity to M1, PMC and the DLPFC (dorsolateral pre-frontal cortex; control condition) before participants had to perform major changes of their trajectory of movement during a tracing task. Each participant performed six trials (20 runs per trial). Task performance and contribution of regions under investigation was quantified through calculating the tracing error induced by the stimulation. Results: A pre-motor stimulation hotspot could be identified in all participants (16.3 ± 1.7 mm medial, 18.6 ± 1.4 mm anterior to the M1 hotspot). NTMS over studied regions significantly affected task performance at discrete time intervals (F(10, 80) = 3.25, p = 0.001). NTMS applied over PMC 120 and 140 ms before changes in movement trajectory impaired task performance significantly more than when applied over M1 (p = 0.021 and p = 0.003) or DLPFC (p = 0.017 and p < 0.001). Stimulation intensity did not account for error size (β = -0.0074, p = 1). Conclusions: We provide novel evidence that the role of pre-motor corticospinal projections extends beyond that of simple corticospinal motor output. Their activation is crucial for task performance early in the stage of motor preparation suggesting a significant role in shaping voluntary movement. Temporal patterns of human pre-motor activation are similar to that observed in intracortical electrophysiological studies in primates.
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Affiliation(s)
- Robert Fleischmann
- Vision and Motor System Research Group, Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Department of Neurology, University Medicine Greifswald, Greifswald, Germany
| | - Paul Triller
- Vision and Motor System Research Group, Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Stephan A. Brandt
- Vision and Motor System Research Group, Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Sein H. Schmidt
- Vision and Motor System Research Group, Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
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14
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Kindred JH, Cash JJ, Ergle JB, Charalambous CC, Wonsetler EC, Bowden MG. Comparing cortico-motor hotspot identification methods in the lower extremities post-stroke: MEP amplitude vs. latency. Neurosci Lett 2021; 754:135884. [PMID: 33862144 DOI: 10.1016/j.neulet.2021.135884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/11/2021] [Accepted: 04/03/2021] [Indexed: 12/22/2022]
Abstract
Transcranial magnetic stimulation (TMS) is a technique used to probe and measure cortico-motor responses of the nervous system. However, lower extremity (LE) specific methodology has been slow to develop. In this retrospective analysis, we investigated what motor evoked potential metric, amplitude (MEPamp) or latency (MEPlat), best distinguished the motor-cortical target, i.e. hotspot, of the tibialis anterior and soleus post-stroke. Twenty-three participants with stroke were included in this investigation. Neuronavigation was used to map hotspots, derived via MEPamp and MEPlat, over a 3cm × 5cm grid. Distances between points with the greatest response within a session and between days were compared. Both criterion, amplitude and latency, provided poor identification of locations between trials within a session, and between multiple visits. Identified hotspots were similar only 15 % and 8% of the time between two assessments within the same session, for amplitude and latency respectively. However, MEPamp was more consistent in identifying hotspots, evidenced by locations being less spatially distant from each other (Amplitude: 1.4 cm (SD 0.10) Latency: 1.7 (SD 1.04), P = 0.008) within a session and between days (Amplitude: 1.3 cm (SD 0.95), Latency 1.9 cm (SD 1.14), P = 0.004). While more work is needed to develop LE specific methodology for TMS, especially as it applies to investigating gait impairments, MEPamp appears to be a more consistent criterion for hotspot identification when compared to MEPlat. It is recommended that future works continue to use MEPamp when identifying tibialis anterior and soleus hotspots using neuronavigation.
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Affiliation(s)
- J H Kindred
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States; Division of Physical Therapy, Department of Rehabilitation Sciences, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - J J Cash
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - J B Ergle
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - C C Charalambous
- Department of Basic and Clinical Sciences, Medical School, University of Nicosia, Nicosia, Cyprus; Center for Neuroscience and Integrative Brain Research (CENIBRE), Medical School, University of Nicosia, Nicosia, Cyprus
| | - E C Wonsetler
- Department of Public Health and Community Medicine, School of Medicine, Tufts University, Boston, MA, United States
| | - M G Bowden
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States; Division of Physical Therapy, Department of Rehabilitation Sciences, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States; Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States.
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15
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Hordacre B, Austin D, Brown KE, Graetz L, Parees I, De Trane S, Vallence AM, Koblar S, Kleinig T, McDonnell MN, Greenwood R, Ridding MC, Rothwell JC. Evidence for a Window of Enhanced Plasticity in the Human Motor Cortex Following Ischemic Stroke. Neurorehabil Neural Repair 2021; 35:307-320. [PMID: 33576318 PMCID: PMC7610679 DOI: 10.1177/1545968321992330] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND In preclinical models, behavioral training early after stroke produces larger gains compared with delayed training. The effects are thought to be mediated by increased and widespread reorganization of synaptic connections in the brain. It is viewed as a period of spontaneous biological recovery during which synaptic plasticity is increased. OBJECTIVE To look for evidence of a similar change in synaptic plasticity in the human brain in the weeks and months after ischemic stroke. METHODS We used continuous theta burst stimulation (cTBS) to activate synapses repeatedly in the motor cortex. This initiates early stages of synaptic plasticity that temporarily reduces cortical excitability and motor-evoked potential amplitude. Thus, the greater the effect of cTBS on the motor-evoked potential, the greater the inferred level of synaptic plasticity. Data were collected from separate cohorts (Australia and UK). In each cohort, serial measurements were made in the weeks to months following stroke. Data were obtained for the ipsilesional motor cortex in 31 stroke survivors (Australia, 66.6 ± 17.8 years) over 12 months and the contralesional motor cortex in 29 stroke survivors (UK, 68.2 ± 9.8 years) over 6 months. RESULTS Depression of cortical excitability by cTBS was most prominent shortly after stroke in the contralesional hemisphere and diminished over subsequent sessions (P = .030). cTBS response did not differ across the 12-month follow-up period in the ipsilesional hemisphere (P = .903). CONCLUSIONS Our results provide the first neurophysiological evidence consistent with a period of enhanced synaptic plasticity in the human brain after stroke. Behavioral training given during this period may be especially effective in supporting poststroke recovery.
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Affiliation(s)
- Brenton Hordacre
- University of South Australia, IIMPACT in Health, Adelaide,
Australia
| | - Duncan Austin
- UCL Institute of Neurology, Queen Square, London, UK
| | | | - Lynton Graetz
- Lifespan Human Neurophysiology group, Adelaide Medical
School, The University of Adelaide, Australia
| | - Isabel Parees
- Servicio de Neurologia, Hospital Universitario Ramón
y Cajal, Madrid, Spain
- Servicio de Neurología, Hospital Ruber
Internacional, Madrid, Spain
| | - Stefania De Trane
- The Blizard Institute, Barts and The London School of
Medicine & Dentistry, Queen Mary University of London, London, UK
- Clinical Board: Medicine (Neuroscience), The Royal London
Hospital, Barts Health NHS Trust, London, UK
- National Hospital for Neurology and Neurosurgery, Queen
Square, London, UK
| | - Ann-Maree Vallence
- Discipline of Psychology, College of Science, Health,
Engineering and Education, Murdoch University, Western Australia, Australia
| | - Simon Koblar
- Department of Medicine, The University of Adelaide,
Adelaide, Australia
- Department of Neurology, Royal Adelaide Hospital,
Adelaide, Australia
| | - Timothy Kleinig
- Department of Medicine, The University of Adelaide,
Adelaide, Australia
- Department of Neurology, Royal Adelaide Hospital,
Adelaide, Australia
| | | | - Richard Greenwood
- National Hospital for Neurology and Neurosurgery, Queen
Square, London, UK
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16
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Shulga A, Lioumis P, Kirveskari E, Savolainen S, Mäkelä JP. A novel paired associative stimulation protocol with a high-frequency peripheral component: A review on results in spinal cord injury rehabilitation. Eur J Neurosci 2021; 53:3242-3257. [PMID: 33738876 DOI: 10.1111/ejn.15191] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/26/2021] [Accepted: 03/12/2021] [Indexed: 12/11/2022]
Abstract
In recent decades, a multitude of therapeutic approaches has been developed for spinal cord injury (SCI), but few have progressed to regular clinical practice. Novel non-invasive, cost-effective, and feasible approaches to treat this challenging condition are needed. A novel variant of paired associative stimulation (PAS), high-PAS, consists of non-invasive high-intensity transcranial magnetic stimulation (TMS) and non-invasive high-frequency electrical peripheral nerve stimulation (PNS). We observed a therapeutic effect of high-PAS in 20 patients with incomplete SCI with wide range of injury severity, age, and time since injury. Tetraplegic and paraplegic, traumatic, and neurological SCI patients benefited from upper- or lower-limb high-PAS. We observed increases in manual motor scores (MMT) of upper and lower limbs, functional hand tests, walking tests, and measures of functional independence. We also optimized PAS settings in several studies in healthy subjects and began elucidating the mechanisms of therapeutic action. The scope of this review is to describe the clinical experience gained with this novel PAS approach. This review is focused on the summary of our results and observations and the methodological considerations for researchers and clinicians interested in adopting and further developing this new method.
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Affiliation(s)
- Anastasia Shulga
- BioMag Laboratory, HUS Diagnostic Center, Helsinki University Hospital, University of Helsinki and Aalto University School of Science, Helsinki, Finland.,Department of Physical and Rehabilitation Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Pantelis Lioumis
- BioMag Laboratory, HUS Diagnostic Center, Helsinki University Hospital, University of Helsinki and Aalto University School of Science, Helsinki, Finland.,Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Erika Kirveskari
- BioMag Laboratory, HUS Diagnostic Center, Helsinki University Hospital, University of Helsinki and Aalto University School of Science, Helsinki, Finland.,HUS Medical Imaging Center, Clinical Neurophysiology; Clinical Neurosciences, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Sarianna Savolainen
- BioMag Laboratory, HUS Diagnostic Center, Helsinki University Hospital, University of Helsinki and Aalto University School of Science, Helsinki, Finland.,Validia Rehabilitation Center, Helsinki, Finland
| | - Jyrki P Mäkelä
- BioMag Laboratory, HUS Diagnostic Center, Helsinki University Hospital, University of Helsinki and Aalto University School of Science, Helsinki, Finland
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17
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Goldsworthy MR, Hordacre B, Rothwell JC, Ridding MC. Effects of rTMS on the brain: is there value in variability? Cortex 2021; 139:43-59. [PMID: 33827037 DOI: 10.1016/j.cortex.2021.02.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 02/16/2021] [Accepted: 02/26/2021] [Indexed: 01/02/2023]
Abstract
The ability of repetitive transcranial magnetic stimulation (rTMS) to non-invasively induce neuroplasticity in the human cortex has opened exciting possibilities for its application in both basic and clinical research. Changes in the amplitude of motor evoked potentials (MEPs) elicited by single-pulse transcranial magnetic stimulation has so far provided a convenient model for exploring the neurophysiology of rTMS effects on the brain, influencing the ways in which these stimulation protocols have been applied therapeutically. However, a growing number of studies have reported large inter-individual variability in the mean MEP response to rTMS, raising legitimate questions about the usefulness of this model for guiding therapy. Although the increasing application of different neuroimaging approaches has made it possible to probe rTMS-induced neuroplasticity outside the motor cortex to measure changes in neural activity that impact other aspects of human behaviour, the high variability of rTMS effects on these measurements remains an important issue for the field to address. In this review, we seek to move away from the conventional facilitation/inhibition dichotomy that permeates much of the rTMS literature, presenting a non-standard approach for measuring rTMS-induced neuroplasticity. We consider the evidence that rTMS is able to modulate an individual's moment-to-moment variability of neural activity, and whether this could have implications for guiding the therapeutic application of rTMS.
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Affiliation(s)
- Mitchell R Goldsworthy
- Lifespan Human Neurophysiology Group, Adelaide Medical School, University of Adelaide, Adelaide, Australia; Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia; Discipline of Psychiatry, Adelaide Medical School, University of Adelaide, Adelaide, Australia.
| | - Brenton Hordacre
- Innovation, IMPlementation and Clinical Translation (IIMPACT) in Health, University of South Australia, Adelaide, Australia
| | - John C Rothwell
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Michael C Ridding
- Innovation, IMPlementation and Clinical Translation (IIMPACT) in Health, University of South Australia, Adelaide, Australia
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18
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Senova S, Lefaucheur JP, Brugières P, Ayache SS, Tazi S, Bapst B, Abhay K, Langeron O, Edakawa K, Palfi S, Bardel B. Case Report: Multimodal Functional and Structural Evaluation Combining Pre-operative nTMS Mapping and Neuroimaging With Intraoperative CT-Scan and Brain Shift Correction for Brain Tumor Surgical Resection. Front Hum Neurosci 2021; 15:646268. [PMID: 33716700 PMCID: PMC7947337 DOI: 10.3389/fnhum.2021.646268] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 02/08/2021] [Indexed: 01/11/2023] Open
Abstract
Background: Maximum safe resection of infiltrative brain tumors in eloquent area is the primary objective in surgical neuro-oncology. This goal can be achieved with direct electrical stimulation (DES) to perform a functional mapping of the brain in patients awake intraoperatively. When awake surgery is not possible, we propose a pipeline procedure that combines advanced techniques aiming at performing a dissection that respects the anatomo-functional connectivity of the peritumoral region. This procedure can benefit from intraoperative monitoring with computerized tomography scan (iCT-scan) and brain shift correction. Associated with this intraoperative monitoring, the additional value of preoperative investigation combining brain mapping by navigated transcranial magnetic stimulation (nTMS) with various neuroimaging modalities (tractography and resting state functional MRI) has not yet been reported. Case Report: A 42-year-old left-handed man had increased intracranial pressure (IICP), left hand muscle deficit, and dysarthria, related to an infiltrative tumor of the right frontal lobe with large mass effect and circumscribed contrast enhancement in motor and premotor cortical areas. Spectroscopy profile and intratumoral calcifications on CT-scan suggested an WHO grade III glioma, later confirmed by histology. The aforementioned surgical procedure was considered, since standard awake surgery was not appropriate for this patient. In preoperative time, nTMS mapping of motor function (deltoid, first interosseous, and tibialis anterior muscles) was performed, combined with magnetic resonance imaging (MRI)-based tractography reconstruction of 6 neural tracts (arcuate, corticospinal, inferior fronto-occipital, uncinate and superior and inferior longitudinal fasciculi) and resting-state functional MRI connectivity (rs-fMRI) of sensorimotor and language networks. In intraoperative time, DES mapping was performed with motor evoked response recording and tumor resection was optimized using non-rigid image transformation of the preoperative data (nTMS, tractography, and rs-fMRI) to iCT data. Image guidance was updated with correction for brain shift and tissue deformation using biomechanical modeling taking into account brain elastic properties. This correction was done at crucial surgical steps, i.e., when tumor bulged through the craniotomy after dura mater opening and when approaching the presumed eloquent brain regions. This procedure allowed a total resection of the tumor region with contrast enhancement as well as a complete regression of IICP and dysarthria. Hand paresis remained stable with no additional deficit. Postoperative nTMS mapping confirmed the good functional outcome. Conclusion: This case report and technical note highlights the value of preoperative functional evaluation by nTMS updated intraoperatively with correction of brain deformation by iCT. This multimodal approach may become the optimized technique of reference for patients with brain tumors in eloquent areas that are unsuitable for awake brain surgery.
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Affiliation(s)
- Suhan Senova
- Department of Neurosurgery, DMU CARe, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France.,Translational Psychiatry (Equipe 15), IMRB - INSERM U955, Univ Paris-Est Creteil, Creteil, France
| | - Jean-Pascal Lefaucheur
- Department of Clinical Neurophysiology, DMU FIxIT, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France.,Excitabilite Nerveuse et Therapeutique, EA 4391, Univ Paris-Est Creteil, Creteil, France
| | - Pierre Brugières
- Department of Neuroradiology, DMU FIxIT, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France
| | - Samar S Ayache
- Department of Clinical Neurophysiology, DMU FIxIT, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France.,Excitabilite Nerveuse et Therapeutique, EA 4391, Univ Paris-Est Creteil, Creteil, France
| | - Sanaa Tazi
- Department of Neurosurgery, DMU CARe, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France.,Translational Psychiatry (Equipe 15), IMRB - INSERM U955, Univ Paris-Est Creteil, Creteil, France
| | - Blanche Bapst
- Department of Neuroradiology, DMU FIxIT, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France
| | - Kou Abhay
- Department of Anesthesiology and Critical Care, DMU CARe, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France
| | - Olivier Langeron
- Department of Anesthesiology and Critical Care, DMU CARe, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France.,Experimental Neuropathology Unit, Institut Pasteur, Paris, France
| | - Kohtaroh Edakawa
- Department of Neurosurgery, DMU CARe, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France.,Translational Psychiatry (Equipe 15), IMRB - INSERM U955, Univ Paris-Est Creteil, Creteil, France.,Department of Neurosurgery, Graduate School of Medicine Osaka University, Suita, Japan
| | - Stéphane Palfi
- Department of Neurosurgery, DMU CARe, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France.,Translational Psychiatry (Equipe 15), IMRB - INSERM U955, Univ Paris-Est Creteil, Creteil, France
| | - Benjamin Bardel
- Department of Clinical Neurophysiology, DMU FIxIT, Henri Mondor University Hospital, Assistance Publique - Hôpitaux de Paris (APHP), Creteil, France.,Excitabilite Nerveuse et Therapeutique, EA 4391, Univ Paris-Est Creteil, Creteil, France
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19
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Alder G, Signal N, Vandal AC, Olsen S, Jochumsen M, Niazi IK, Taylor D. Investigating the Intervention Parameters of Endogenous Paired Associative Stimulation (ePAS). Brain Sci 2021; 11:brainsci11020224. [PMID: 33673171 PMCID: PMC7918620 DOI: 10.3390/brainsci11020224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 01/20/2021] [Accepted: 02/04/2021] [Indexed: 11/16/2022] Open
Abstract
Advances in our understanding of neural plasticity have prompted the emergence of neuromodulatory interventions, which modulate corticomotor excitability (CME) and hold potential for accelerating stroke recovery. Endogenous paired associative stimulation (ePAS) involves the repeated pairing of a single pulse of peripheral electrical stimulation (PES) with endogenous movement-related cortical potentials (MRCPs), which are derived from electroencephalography. However, little is known about the optimal parameters for its delivery. A factorial design with repeated measures delivered four different versions of ePAS, in which PES intensities and movement type were manipulated. Linear mixed models were employed to assess interaction effects between PES intensity (suprathreshold (Hi) and motor threshold (Lo)) and movement type (Voluntary and Imagined) on CME. ePAS interventions significantly increased CME compared to control interventions, except in the case of Lo-Voluntary ePAS. There was an overall main effect for the Hi-Voluntary ePAS intervention immediately post-intervention (p = 0.002), with a sub-additive interaction effect at 30 min’ post-intervention (p = 0.042). Hi-Imagined and Lo-Imagined ePAS significantly increased CME for 30 min post-intervention (p = 0.038 and p = 0.043 respectively). The effects of the two PES intensities were not significantly different. CME was significantly greater after performing imagined movements, compared to voluntary movements, with motor threshold PES (Lo) 15 min post-intervention (p = 0.012). This study supports previous research investigating Lo-Imagined ePAS and extends those findings by illustrating that ePAS interventions that deliver suprathreshold intensities during voluntary or imagined movements (Hi-Voluntary and Hi-Imagined) also increase CME. Importantly, our findings indicate that stimulation intensity and movement type interact in ePAS interventions. Factorial designs are an efficient way to explore the effects of manipulating the parameters of neuromodulatory interventions. Further research is required to ensure that these parameters are appropriately refined to maximise intervention efficacy for people with stroke and to support translation into clinical practice.
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Affiliation(s)
- Gemma Alder
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland 0627, New Zealand; (N.S.); (S.O.); (I.K.N.); (D.T.)
- Correspondence:
| | - Nada Signal
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland 0627, New Zealand; (N.S.); (S.O.); (I.K.N.); (D.T.)
| | - Alain C. Vandal
- Department of Statistics, University of Auckland, Auckland 1142, New Zealand;
- Ko Awatea, Counties Manukau Health, Auckland 2025, New Zealand
| | - Sharon Olsen
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland 0627, New Zealand; (N.S.); (S.O.); (I.K.N.); (D.T.)
| | - Mads Jochumsen
- Department of Health Science and Technology, Aalborg University, 9000 Aalborg, Denmark;
| | - Imran Khan Niazi
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland 0627, New Zealand; (N.S.); (S.O.); (I.K.N.); (D.T.)
- Department of Health Science and Technology, Aalborg University, 9000 Aalborg, Denmark;
- Centre for Chiropractic Research, New Zealand College of Chiropractic, Auckland 1060, New Zealand
| | - Denise Taylor
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland 0627, New Zealand; (N.S.); (S.O.); (I.K.N.); (D.T.)
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20
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Kim H, Kim J, Lee HJ, Lee J, Na Y, Chang WH, Kim YH. Optimal stimulation site for rTMS to improve motor function: Anatomical hand knob vs. hand motor hotspot. Neurosci Lett 2020; 740:135424. [PMID: 33075419 DOI: 10.1016/j.neulet.2020.135424] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 01/28/2023]
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is used to modulate neuronal excitability of the human brain. Distant effects on contralateral corticomotor excitability can be exerted by interhemispheric modulation by low-frequency rTMS on ipsilateral hemisphere. To modulate corticospinal excitability, accurate determination of the stimulation site is important to maximize the effects of rTMS. In the present study, we investigated the difference in the distant effect of 1 Hz rTMS with respect to inducing functional improvement in the non-dominant hand by inhibiting the dominant hemisphere depending on cortical target areas. Ten healthy right-handed volunteers without any neurological disorders were enrolled. The anatomical hand knob (HK) identified from individual magnetic resonance imaging and the transcranial magnetic stimulation (TMS) induced hand motor hotspot (hMHS) by recording motor evoked potentials (MEPs) in the contralateral first dorsal interosseous muscle were determined. All participants underwent three conditions of 1 Hz rTMS on left hemisphere intervention; rTMS application over the HK, rTMS application over the hMHS, and sham-rTMS. Before and after each intervention, all participants undergone motor function assessments with their left hand. The cortical mapping showed that the hMHS was located anteriorly and laterally compared to the HK. Motor function tests showed the most significant improvements after the hMHS stimulation. When we compared the distant effects of target site on corticospinal excitability and motor behavior, delivering 1 Hz rTMS to the hMHS was more effective than delivering it to the HK for improving corticomotor excitability, motor skill, and dexterity. These results suggest that TMS-induced hMHS is an optimal target area to induce distant effect of low-frequency rTMS in motor function.
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Affiliation(s)
- Heegoo Kim
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea
| | - Jinuk Kim
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea
| | - Hwang-Jae Lee
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea
| | - Jungsoo Lee
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Yoonju Na
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Won Hyuk Chang
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Yun-Hee Kim
- Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea; Department of Medical Device Management & Research, Department of Digital Health, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea.
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21
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Makarov SN, Wartman WA, Daneshzand M, Fujimoto K, Raij T, Nummenmaa A. A software toolkit for TMS electric-field modeling with boundary element fast multipole method: an efficient MATLAB implementation. J Neural Eng 2020; 17:046023. [PMID: 32235065 DOI: 10.1088/1741-2552/ab85b3] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Objective To present and disseminate our transcranial magnetic stimulation (TMS) modeling software toolkit, including several new algorithmic developments, and to apply this software to realistic TMS modeling scenarios given a high-resolution model of the human head including cortical geometry and an accurate coil model. Approach The recently developed charge-based boundary element fast multipole method (BEM-FMM) is employed as an alternative to the 1st order finite element method (FEM) most commonly used today. The BEM-FMM approach provides high accuracy and unconstrained numerical field resolution close to and across cortical interfaces. Here, the previously proposed BEM-FMM algorithm has been improved in several novel ways. Main results The improvements resulted in a threefold increase in computational speed while maintaining the same solution accuracy. The computational code based on the MATLAB® platform is made available to all interested researchers, along with a coil model repository and examples to create custom coils, head model repository, and supporting documentation. The presented software toolkit may be useful for post-hoc analyses of navigated TMS data using high-resolution subject-specific head models as well as accurate and fast modeling for the purposes of TMS coil/hardware development. Significance TMS is currently the only non-invasive neurostimulation modality that enables painless and safe supra-threshold stimulation by employing electromagnetic induction to efficiently penetrate the skull. Accurate, fast, and high resolution modeling of the electric fields may significantly improve individualized targeting and dosing of TMS and therefore enhance the efficiency of existing clinical protocols as well as help establish new application domains.
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Affiliation(s)
- Sergey N Makarov
- Electrical & Computer Engineering Department, Worcester Polytechnic Institute, Worcester, MA 01609 United States of America. Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115 United States of America. Author to whom any correspondence should be addressed
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22
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Fleischmann R, Köhn A, Tränkner S, Brandt SA, Schmidt S. Individualized Template MRI Is a Valid and Reliable Alternative to Individual MRI for Spatial Tracking in Navigated TMS Studies in Healthy Subjects. Front Hum Neurosci 2020; 14:174. [PMID: 32477086 PMCID: PMC7241258 DOI: 10.3389/fnhum.2020.00174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/20/2020] [Indexed: 11/28/2022] Open
Abstract
Objectives: Navigated transcranial magnetic stimulation (nTMS) provides significant benefits over classic TMS. Yet, the acquisition of individual structural magnetic resonance images (MRIindividual) is a time-consuming, expensive, and not feasible prerequisite in all subjects for spatial tracking and anatomical guidance in nTMS studies. We hypothesize that spatial transformation can be used to adjust MRI templates to individual head shapes (MRIwarped) and that TMS parameters do not differ between nTMS using MRIindividual or MRIwarped. Materials and Methods: Twenty identical TMS sessions, each including four different navigation conditions, were conducted in 10 healthy subjects (one female, 27.4 ± 3.8 years), i.e., twice per subject by two researchers to additionally assess interrater reliabilities. MRIindividual were acquired for all subjects. MRIwarped were obtained through the spatial transformation of a template MRI following a 5-, 9-and 36-point head surface registration (MRIwarped_5, MRIwarped_9, MRIwarped_36). Stimulation hotspot locations, resting motor threshold (RMT), 500 μV motor threshold (500 μV-MT), and mean absolute motor evoked potential difference (MAD) of primary motor cortex (M1) examinations were compared between nTMS using either MRIwarped variants or MRIindividual and non-navigated TMS. Results: M1 hotspots were spatially consistent between MRIindividual and MRIwarped_36 (insignificant deviation by 4.79 ± 2.62 mm). MEP thresholds and variance were also equivalent between MRIindividual and MRIwarped_36 with mean differences of RMT by −0.05 ± 2.28% maximum stimulator output (%MSO; t(19) = −0.09, p = 0.923), 500 μV-MT by −0.15 ± 1.63%MSO (t(19) = −0.41, p = 0.686) and MAD by 70.5 ± 214.38 μV (t(19) = 1.47, p = 0.158). Intraclass correlations (ICC) of motor thresholds were between 0.88 and 0.97. Conclusions: NTMS examinations of M1 yield equivalent topographical and functional results using MRIindividual and MRIwarped if a sufficient number of registration points are used.
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Affiliation(s)
- Robert Fleischmann
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Neurology, University Medicine Greifswald, Greifswald, Germany
| | - Arvid Köhn
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Steffi Tränkner
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Stephan A Brandt
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sein Schmidt
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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23
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Mioni G, Grondin S, Bardi L, Stablum F. Understanding time perception through non-invasive brain stimulation techniques: A review of studies. Behav Brain Res 2020; 377:112232. [DOI: 10.1016/j.bbr.2019.112232] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/06/2019] [Accepted: 09/11/2019] [Indexed: 01/08/2023]
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24
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Hui J, Lioumis P, Blumberger DM, Daskalakis ZJ. Non-invasive Central Neuromodulation with Transcranial Magnetic Stimulation. Stereotact Funct Neurosurg 2020. [DOI: 10.1007/978-3-030-34906-6_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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25
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Reijonen J, Säisänen L, Könönen M, Mohammadi A, Julkunen P. The effect of coil placement and orientation on the assessment of focal excitability in motor mapping with navigated transcranial magnetic stimulation. J Neurosci Methods 2019; 331:108521. [PMID: 31733284 DOI: 10.1016/j.jneumeth.2019.108521] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/26/2019] [Accepted: 11/12/2019] [Indexed: 11/17/2022]
Abstract
BACKGROUND Navigated transcranial magnetic stimulation (nTMS) is used for mapping muscle representations in the primary motor cortex. We used sulcus-aligned mapping and electric field (E-field) modeling to investigate the excitability of the motor hand area for further understanding the methodological limitations of nTMS. NEW METHOD We studied 10 healthy volunteers to locate the cortical target eliciting the largest responses (the hotspot) in the first dorsal interosseous (FDI) muscle. Six additional targets were placed along the central sulcus at 5-mm distances. Resting motor thresholds (rMTs) and optimal coil orientations were determined at all targets, and a conventional motor mapping was conducted. The cortical E-fields, induced by stimulating the targets with rMT intensities and optimal coil orientations, were modeled in a realistic head geometry to estimate the activated cortical sites. RESULTS The rMTs increased with increasing distance from the hotspot (p < 0.001). The greatest motor-evoked potential (MEP) amplitudes occurred with the coil perpendicular to the sulcus and with the coil pointing towards the hotspot or the center of gravity of the motor map. The E-field strengths at the hotspot (99±26 V/m) remained above previously estimated thresholds for activation. COMPARISON WITH EXISTING METHODS Depending on the target location, optimal coil orientations may deviate significantly from the conventional perpendicular-to-sulcus angle, which is often assumed optimal. These orientations seem to maintain the E-field stable in the hand knob, regardless of the sulcal shape near the stimulated target. CONCLUSIONS The coil orientation is crucial for the accuracy of motor mapping, and the apparent motor map may extend due to remote hotspot activation.
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Affiliation(s)
- Jusa Reijonen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
| | - Laura Säisänen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
| | - Mervi Könönen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Kuopio, Finland; Department of Clinical Radiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Kuopio, Finland.
| | - Ali Mohammadi
- Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
| | - Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
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26
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Nguyen DTA, Rissanen SM, Julkunen P, Kallioniemi E, Karjalainen PA. Principal Component Regression on Motor Evoked Potential in Single-Pulse Transcranial Magnetic Stimulation. IEEE Trans Neural Syst Rehabil Eng 2019; 27:1521-1528. [DOI: 10.1109/tnsre.2019.2923724] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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27
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de Goede AA, van Putten MJAM. Infraslow activity as a potential modulator of corticomotor excitability. J Neurophysiol 2019; 122:325-335. [PMID: 31116669 DOI: 10.1152/jn.00663.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fluctuations in cortical excitability are a candidate mechanism involved in the trial-to-trial variation of motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS). We explore whether infraslow EEG activity (<0.1 Hz) modulates corticomotor excitability by evaluating the presence of temporal and phase clustering of TMS-induced MEPs. In addition, we evaluate the dependence of MEP amplitude on the phase of the infraslow activity. Twenty-three subjects were stimulated at an intensity above the resting motor threshold (rMT) and ten at the rMT. We evaluated whether temporal and phase clustering of MEP size and MEP generation were present, using 1,000 surrogates with a similar amplitude or occurrence distribution. To evaluate the MEP amplitude dependence, we used the least-square method to approximate the linear circular data by fitting a sine function. We observed significant temporal clustering at a group level, in all individual subjects stimulated at rMT and in the majority of those stimulated above rMT, suggesting underlying determinism of corticomotor excitability instead of randomly generated fluctuations. The majority of subjects showed significant phase clustering for MEP size and for MEP occurrence, and significant phase clustering was found at the group level. Furthermore, in approximately one-quarter to one-half of the subjects we found a significant correlation and dependence of MEP amplitude on the phase of infraslow activity, respectively. Although other mechanisms very likely contribute as well, our findings seem to suggest that infraslow activity is involved in the variability of cortical excitability and TMS-induced responses. NEW & NOTEWORTHY Cortical excitability measures are highly variable during transcranial magnetic stimulation. Although ongoing brain oscillations are assumed to modulate excitability, no consistent associations are found for the traditional frequency bands. We focus on the role of infraslow EEG activity, defined as rhythms with frequencies < 0.1 Hz. We provide experimental evidence suggesting that infraslow activity most likely modulates corticomotor excitability and that response variation could be reduced when stimulation is targeted at a specific infraslow phase.
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Affiliation(s)
- Annika A de Goede
- Department of Clinical Neurophysiology, Technical Medical Centre, University of Twente , Enschede , The Netherlands
| | - Michel J A M van Putten
- Department of Clinical Neurophysiology, Technical Medical Centre, University of Twente , Enschede , The Netherlands.,Department of Neurology and Clinical Neurophysiology, Medisch Spectrum Twente, Enschede , The Netherlands
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28
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Fang X, Liu M, Lu C, Zhao Y, Liu X. Current status and potential application of navigated transcranial magnetic stimulation in neurosurgery: a literature review. Chin Neurosurg J 2019; 5:12. [PMID: 32922912 PMCID: PMC7398385 DOI: 10.1186/s41016-019-0159-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 04/25/2019] [Indexed: 12/13/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) is a noninvasive neurophysiologic technique that can stimulate the human brain. Positioning of the coil was often performed based merely on external landmarks on the head, meaning that the anatomical target in the cortex remains inaccurate. Navigated transcranial magnetic stimulation (nTMS) combines a frameless stereotactic navigational system and TMS coil and can provide a highly accurate delivery of TMS pulses with the guidance of imaging. Therefore, many novel utilities for TMS could be explored due to the ability of precise localization. Many studies have been published, which indicate nTMS enables presurgical functional mapping. This review aimed to provide a comprehensive literature review on nTMS, especially the principles and clinical applications of nTMS. All articles in PubMed with keywords of "motor mapping," "presurgical mapping," "navigated transcranial magnetic stimulation," and "language mapping" published from 2000 to 2018 were included in the study. Frequently cited publications before 2000 were also included. The most valuable published original and review articles related to our objective were selected. Motor mapping of nTMS is validated to be a trustful tool to recognize functional areas belonging to both normal and lesioned primary motor cortex. It can offer reliable mapping of speech and motor regions at cortex prior to operation and has comparable accuracy as direct electrical cortical stimulation. nTMS is a powerful tool for mapping of motor and linguistic function prior to operation, has high application value in neurosurgery and the treatment of neurological and psychiatric diseases, and has gained increasing acceptance in neurosurgical centers across the world.
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Affiliation(s)
- Xiaojing Fang
- Department of Neurology, Peking University International Hospital, 1 Life Science St, Changping District, Beijing, 102206 China
| | - Meige Liu
- Department of Neurology, Peking University People's Hospital, Beijing, 100044 China
| | - Changyu Lu
- Department of Neurosurgery, Peking University International Hospital, Beijing, 102206 China
| | - Yuanli Zhao
- Neurosurgery Center, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China.,Department of Neurosurgery, Peking University International Hospital, Beijing, 102206 China
| | - Xianzeng Liu
- Department of Neurology, Peking University International Hospital, 1 Life Science St, Changping District, Beijing, 102206 China
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29
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Pitkänen M, Yazawa S, Airaksinen K, Lioumis P, Nurminen J, Pekkonen E, Mäkelä JP. Localization of Sensorimotor Cortex Using Navigated Transcranial Magnetic Stimulation and Magnetoencephalography. Brain Topogr 2019; 32:873-881. [PMID: 31093863 PMCID: PMC6707977 DOI: 10.1007/s10548-019-00716-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 05/06/2019] [Indexed: 12/17/2022]
Abstract
The mapping of the sensorimotor cortex gives information about the cortical motor and sensory functions. Typical mapping methods are navigated transcranial magnetic stimulation (TMS) and magnetoencephalography (MEG). The differences between these mapping methods are, however, not fully known. TMS center of gravities (CoGs), MEG somatosensory evoked fields (SEFs), corticomuscular coherence (CMC), and corticokinematic coherence (CKC) were mapped in ten healthy adults. TMS mapping was performed for first dorsal interosseous (FDI) and extensor carpi radialis (ECR) muscles. SEFs were induced by tactile stimulation of the index finger. CMC and CKC were determined as the coherence between MEG signals and the electromyography or accelerometer signals, respectively, during voluntary muscle activity. CMC was mapped during the activation of FDI and ECR muscles separately, whereas CKC was measured during the waving of the index finger at a rate of 3–4 Hz. The maximum CMC was found at beta frequency range, whereas maximum CKC was found at the movement frequency. The mean Euclidean distances between different localizations were within 20 mm. The smallest distance was found between TMS FDI and TMS ECR CoGs and longest between CMC FDI and CMC ECR sites. TMS-inferred localizations (CoGs) were less variable across participants than MEG-inferred localizations (CMC, CKC). On average, SEF locations were 8 mm lateral to the TMS CoGs (p < 0.01). No differences between hemispheres were found. Based on the results, TMS appears to be more viable than MEG in locating motor cortical areas.
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Affiliation(s)
- Minna Pitkänen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland. .,Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland. .,A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P. O. Box 1627, 70211, Kuopio, Finland.
| | - Shogo Yazawa
- Department of Systems Neuroscience, Sapporo Medical University, Sapporo, Japan
| | - Katja Airaksinen
- BioMag Laboratory, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.,Department of Neurology, Helsinki University Hospital, Helsinki, Finland.,Department of Clinical Neurosciences (Neurology), University of Helsinki, Helsinki, Finland
| | - Pantelis Lioumis
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland.,BioMag Laboratory, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Jussi Nurminen
- BioMag Laboratory, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Eero Pekkonen
- Department of Neurology, Helsinki University Hospital, Helsinki, Finland.,Department of Clinical Neurosciences (Neurology), University of Helsinki, Helsinki, Finland
| | - Jyrki P Mäkelä
- BioMag Laboratory, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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30
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Lam S, Lucente G, Schneider H, Picht T. TMS motor mapping in brain tumor patients: more robust maps with an increased resting motor threshold. Acta Neurochir (Wien) 2019; 161:995-1002. [PMID: 30927156 DOI: 10.1007/s00701-019-03883-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/20/2019] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Navigated transcranial magnetic stimulation (nTMS) has found widespread usage across many clinical centers as part of their surgical planning routines. NTMS offers a non-invasive approach to delineation of the motor cortex, in which the region is outlined through electromagnetic stimulation and electromyographic recordings of target muscles. Several neurophysiological parameters such as the motor evoked potential (MEP) and its derivatives, the resting motor threshold (RMT) and motor latency, are collected. The present study investigates the clinical feasibility and reproducibility of increasing the MEP threshold in brain tumor patients, with the goal to improve the robustness of the procedure. MATERIALS AND METHODS Twenty-three subjects with peri-motor cortex tumors underwent motor mapping with nTMS. RMT was calculated with both conventional 50-μV and experimental 500-μV MEP amplitude thresholds. Motor mapping was performed with 105% of both RMTs stimulator intensity using the FDI as the target muscle. RESULTS Motor mapping was possible in 20 patients with both the conventional and experimental thresholds. No significant differences in area size were found between motor area maps generated with a conventional 50-μV threshold in comparison to those generated with the higher 500-μV threshold (50 μV 272.56 mm2 [170.47-434.31] vs. 500 μV 240.54 mm2 [169.77-362.84], P = 0.34). Latency time was significantly reduced in 500-μV recordings relative to 50-μV recordings (50 μV 23.38 ms [22.55-24.51] vs. 500 μV 22.57 ms [21.41-23.70], P < 0.001). Both electric field intensity (50 μV 63.81 V/m [54.26-76.11] vs. 500 μV 77.83 V/m [65.21-93.94], P < 0.001) and RMT (50 μV 33 MSO% [28-36] vs. 500 μV 39.5 MSO% [32-44], P < 0.001) were significantly greater with the higher 500-μV threshold. CONCLUSIONS Our study demonstrates the feasibility of increasing the MEP detection threshold to 500 μV in brain tumor patients for RMT determination and motor area mapping with nTMS.
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Affiliation(s)
- Steven Lam
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Giuseppe Lucente
- Neuroscience Department, Hospital Universitari Germans Trias I Pujol, Carretera del Canyet s/n, 08916, Badalona, Spain.
- Medicine Department, Universitat Autònoma de Barcelona (UAB), Barcelona, Spain.
| | - Heike Schneider
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas Picht
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Berlin, Germany
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31
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False positives associated with responder/non-responder analyses based on motor evoked potentials. Brain Stimul 2019; 12:314-318. [DOI: 10.1016/j.brs.2018.11.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/24/2018] [Accepted: 11/29/2018] [Indexed: 11/23/2022] Open
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32
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Jooss A, Haberbosch L, Köhn A, Rönnefarth M, Bathe-Peters R, Kozarzewski L, Fleischmann R, Scholz M, Schmidt S, Brandt SA. Motor Task-Dependent Dissociated Effects of Transcranial Random Noise Stimulation in a Finger-Tapping Task Versus a Go/No-Go Task on Corticospinal Excitability and Task Performance. Front Neurosci 2019; 13:161. [PMID: 30872997 PMCID: PMC6400855 DOI: 10.3389/fnins.2019.00161] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/12/2019] [Indexed: 01/18/2023] Open
Abstract
Background and Objective: Transcranial random noise stimulation (tRNS) is an emerging non-invasive brain stimulation technique to modulate brain function, with previous studies highlighting its considerable benefits in therapeutic stimulation of the motor system. However, high variability of results and bidirectional task-dependent effects limit more widespread clinical application. Task dependency largely results from a lack of understanding of the interaction between externally applied tRNS and the endogenous state of neural activity during stimulation. Hence, the aim of this study was to investigate the task dependency of tRNS-induced neuromodulation in the motor system using a finger-tapping task (FT) versus a go/no-go task (GNG). We hypothesized that the tasks would modulate tRNS’ effects on corticospinal excitability (CSE) and task performance in opposite directions. Methods: Thirty healthy subjects received 10 min of tRNS of the dominant primary motor cortex in a double-blind, sham-controlled study design. tRNS was applied during two well-established tasks tied to diverging brain states. Accordingly, participants were randomly assigned to two equally-sized groups: the first group performed a simple motor training task (FT task), known primarily to increase CSE, while the second group performed an inhibitory control task (go/no-go task) associated with inhibition of CSE. To establish task-dependent effects of tRNS, CSE was evaluated prior to- and after stimulation with navigated transcranial magnetic stimulation. Results: In an ‘activating’ motor task, tRNS during FT significantly facilitated CSE. FT task performance improvements, shown by training-related reductions in intertap intervals and increased number of finger taps, were similar for both tRNS and sham stimulation. In an ‘inhibitory’ motor task, tRNS during GNG left CSE unchanged while inhibitory control was enhanced as shown by slowed reaction times and enhanced task accuracy during and after stimulation. Conclusion: We provide evidence that tRNS-induced neuromodulatory effects are task-dependent and that resulting enhancements are specific to the underlying task-dependent brain state. While mechanisms underlying this effect require further investigation, these findings highlight the potential of tRNS in enhancing task-dependent brain states to modulate human behavior.
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Affiliation(s)
- Andreas Jooss
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Linus Haberbosch
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Arvid Köhn
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Maria Rönnefarth
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Rouven Bathe-Peters
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Leonard Kozarzewski
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Robert Fleischmann
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Michael Scholz
- Neural Information Processing Group, Technische Universität Berlin, Berlin, Germany
| | - Sein Schmidt
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Stephan A Brandt
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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Meincke J, Hewitt M, Reischl M, Rupp R, Schmidt-Samoa C, Liebetanz D. Cortical representation of auricular muscles in humans: A robot-controlled TMS mapping and fMRI study. PLoS One 2018; 13:e0201277. [PMID: 30052653 PMCID: PMC6065161 DOI: 10.1371/journal.pone.0201277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 07/12/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Most humans have the ability to activate the auricular muscles. Although (intentional) control suggests an involvement of higher cortical centers underlying posterior auricular muscle (PAM) activation, the cortical representation of the auricular muscles is still unknown. METHODS With the purpose of identifying a possible cortical representation area we performed automated robotic and image-guided transcranial magnetic stimulation (TMS) mapping (n = 8) and functional magnetic resonance imaging (fMRI) (n = 13). For topographical comparison, a similar experimental protocol was applied for the first dorsal interosseus muscle (FDI) of the hand. RESULTS The calculated centers of gravity (COGs) of both muscles were located on the precentral gyrus with the PAM COGs located more laterally compared to the FDI. The distance between the mean PAM and mean FDI COG was 26.3 mm. The TMS mapping results were confirmed by fMRI, which showed a dominance of cortical activation within the precentral gyrus during the corresponding motor tasks. The correspondence of TMS and fMRI results was high. CONCLUSION The involvement of the primary motor cortex in PAM activation might point to an evolved function of the auricular muscles in humans and/or the ability of intentional (and selective) muscle activation.
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Affiliation(s)
- Jonna Meincke
- Clinic of Clinical Neurophysiology, Georg August University of Göttingen,
University Medical Center, Göttingen, Germany
| | - Manuel Hewitt
- Clinic of Clinical Neurophysiology, Georg August University of Göttingen,
University Medical Center, Göttingen, Germany
| | - Markus Reischl
- Institute for Applied Computer Science, Karlsruhe Institute of
Technology, Eggenstein-Leopoldshafen, Germany
| | - Rüdiger Rupp
- Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg,
Germany
| | - Carsten Schmidt-Samoa
- Department of Cognitive Neurology, Georg August University of Göttingen,
University Medical Center, Göttingen, Germany
| | - David Liebetanz
- Clinic of Clinical Neurophysiology, Georg August University of Göttingen,
University Medical Center, Göttingen, Germany
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Rodseth J, Washabaugh EP, Krishnan C. A novel low-cost approach for navigated transcranial magnetic stimulation. Restor Neurol Neurosci 2018; 35:601-609. [PMID: 29036851 DOI: 10.3233/rnn-170751] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) is commonly used for assessing or modulating brain excitability. However, the credibility of TMS outcomes depends on accurate and reliable coil placement during stimulation. Navigated TMS systems can address this issue, but these systems are expensive for routine use in clinical and research environments. OBJECTIVE The purpose of this study was to provide a high-quality open source framework for navigated TMS and test its reliability and accuracy using standard TMS procedures. METHODS A navigated TMS system was created using a low-cost 3D camera system (OptiTrack Trio), which communicates with our free and open source software environment programmed using the Unity 3D gaming engine. The environment is user friendly and has functions to allow for a variety of stimulation procedures (e.g., head and coil co-registration, multiple hotspot/grid tracking, intuitive matching, and data logging). The system was then validated using a static mockup of a TMS session. The clinical utility was also evaluated by assessing the repeatability and operator accuracy when collecting motor evoked potential (MEP) data from human subjects. RESULTS The system was highly reliable and improved coil placement accuracy (position error = 1.2 mm and orientation error = 0.3°) as well as the quality and consistency (ICC >0.95) of MEPs recorded during TMS. CONCLUSION These results indicate that the proposed system is a viable tool for reliable coil placement during TMS procedures, and can improve accuracy in locating the coil over a desired hotspot both within and between sessions.
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Affiliation(s)
- Jakob Rodseth
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Edward P Washabaugh
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA.,Deparment of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Chandramouli Krishnan
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA.,School of Kinesiology, University of Michigan, Ann Arbor, MI, USA.,Deparment of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
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de Goede AA, Ter Braack EM, van Putten MJAM. Accurate Coil Positioning is Important for Single and Paired Pulse TMS on the Subject Level. Brain Topogr 2018; 31:917-930. [PMID: 29943242 PMCID: PMC6182440 DOI: 10.1007/s10548-018-0655-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 06/07/2018] [Indexed: 12/04/2022]
Abstract
Function-guided navigation is commonly used when assessing cortical excitability using transcranial magnetic stimulation (TMS). However, the required accuracy, stability and the effect of a change in coil positioning are not entirely known. This study investigates the accuracy of function-guided navigation for determining the hotspot. Furthermore, it evaluates the effect of a change in coil location on the single and paired pulse excitability measures: motor evoked potential (MEP) amplitude, TMS evoked potential (TEP) and long intracortical inhibition (LICI), and of a change in coil orientation on LICI. Eight healthy subjects participated in the single pulse study, and ten in the paired pulse study. A robot-guided navigation system was used to ensure accurate and stable coil positioning at the motor hotspot as determined using function-guided navigation. In addition, we targeted four locations at 2 mm and four at 5 mm distance around the initially defined hotspot, and we increased and decreased the coil orientation by 10°. In none of the subjects, the largest MEP amplitudes were evoked at the originally determined hotspot, resulting in a poor accuracy of function-guided navigation. At the group level, a change in coil location had no significant effect on the MEP amplitude, TEP, or LICI, and a change in coil orientation did not significantly affected LICI. However, at the subject level significant effects on MEP amplitude, TEP, and LICI were found for changes in coil location or orientation, although absolute differences were relatively small and did not show a consistent pattern. This study indicates that a high accuracy in coil positioning is especially required to measure cortical excitability reliably in individual subjects using single or paired pulse TMS.
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Affiliation(s)
- Annika A de Goede
- Department of Clinical Neurophysiology, Technical Medical Centre, University of Twente, Carré 3.714, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
| | - Esther M Ter Braack
- Department of Clinical Neurophysiology, Technical Medical Centre, University of Twente, Carré 3.714, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Michel J A M van Putten
- Department of Clinical Neurophysiology, Technical Medical Centre, University of Twente, Carré 3.714, P.O. Box 217, 7500 AE, Enschede, The Netherlands
- Department of Neurology and Clinical Neurophysiology, Medisch Spectrum Twente, Enschede, The Netherlands
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Development of corticospinal motor excitability and cortical silent period from mid-childhood to adulthood – a navigated TMS study. Neurophysiol Clin 2018; 48:65-75. [DOI: 10.1016/j.neucli.2017.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 10/26/2017] [Accepted: 11/29/2017] [Indexed: 01/06/2023] Open
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Lucente G, Lam S, Schneider H, Picht T. Preservation of motor maps with increased motor evoked potential amplitude threshold in RMT determination. Acta Neurochir (Wien) 2018; 160:325-330. [PMID: 29214399 DOI: 10.1007/s00701-017-3417-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/27/2017] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Non-invasive pre-surgical mapping of eloquent brain areas with navigated transcranial magnetic stimulation (nTMS) is a useful technique linked to the improvement of surgical planning and patient outcomes. The stimulator output intensity and subsequent resting motor threshold determination (rMT) are based on the motor-evoked potential (MEP) elicited in the target muscle with an amplitude above a predetermined threshold of 50 μV. However, a subset of patients is unable to achieve complete relaxation in the target muscles, resulting in false positives that jeopardize mapping validity with conventional MEP determination protocols. Our aim is to explore the feasibility and reproducibility of a novel mapping approach that investigates how an increase of the MEP amplitude threshold to 300 and 500 μV affects subsequent motor maps. MATERIALS AND METHODS Seven healthy subjects underwent motor mapping with nTMS. RMT was calculated with the conventional methodology in conjunction with experimental 300- and 500-μV MEP amplitude thresholds. Motor mapping was performed with 105% of rMT stimulator intensity using the FDI as the target muscle. RESULTS Motor mapping was possible in all patients with both the conventional and experimental setups. Motor area maps with a conventional 50-μV threshold showed poor correlation with 300-μV (α = 0.446, p < 0.001) maps, but showed excellent consistency with 500-μV motor area maps (α = 0.974, p < 0.001). MEP latencies were significantly less variable (23 ms for 50 μV vs. 23.7 ms for 300 μV vs. 23.7 ms for 500 μV, p < 0.001). A slight but significant increase of the electric field (EF) value was found (EF: 60.8 V/m vs. 64.8 V/m vs. 66 V/m p < 0.001). CONCLUSION Our study demonstrates the feasibility of increasing the MEP detection threshold to 500 μV in rMT determination and motor area mapping with nTMS without losing precision.
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Affiliation(s)
- Giuseppe Lucente
- Neuroscience Department, Hospital Universitari Germans Trias I Pujol, Barcelona, Spain.
| | - Steven Lam
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Heike Schneider
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas Picht
- Department of Neurosurgery, Charité Universitätsmedizin Berlin, Berlin, Germany
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Ambrosini E, Ferrante S, van de Ruit M, Biguzzi S, Colombo V, Monticone M, Ferriero G, Pedrocchi A, Ferrigno G, Grey MJ. StimTrack: An open-source software for manual transcranial magnetic stimulation coil positioning. J Neurosci Methods 2018; 293:97-104. [PMID: 28935421 DOI: 10.1016/j.jneumeth.2017.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 08/29/2017] [Accepted: 09/17/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND During Transcranial Magnetic Stimulation (TMS) experiments researchers often use a neuronavigation system to precisely and accurately maintain coil position and orientation. NEW METHOD This study aimed to develop and validate an open-source software for TMS coil navigation. StimTrack uses an optical tracker and an intuitive user interface to facilitate the maintenance of position and orientation of any type of coil within and between sessions. Additionally, online access to navigation data is provided, hereby adding e.g. the ability to start or stop the magnetic stimulator depending on the distance to target or the variation of the orientation angles. RESULTS StimTrack allows repeatable repositioning of the coil within 0.7mm for translation and <1° for rotation. Stimulus-response (SR) curves obtained from 19 healthy volunteers were used to demonstrate that StimTrack can be effectively used in a typical experiment. An excellent intra and inter-session reliability (ICC >0.9) was obtained on all parameters computed on SR curves acquired using StimTrack. COMPARISON WITH EXISTING METHOD StimTrack showed a target accuracy similar to that of a commercial neuronavigation system (BrainSight, Rogue Research Inc.). Indeed, small differences both in position (∼0.2mm) and orientation (<1°) were found between the systems. These differences are negligible given the human error involved in landmarks registration. CONCLUSIONS StimTrack, available as supplementary material, is found to be a good alternative for commercial neuronavigation systems facilitating assessment changes in corticospinal excitability using TMS. StimTrack allows researchers to tailor its functionality to their specific needs, providing added value that benefits experimental procedures and improves data quality.
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Affiliation(s)
- Emilia Ambrosini
- Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy; Department of Physical and Rehabilitative Medicine, Scientific Institute of Lissone IRCCS, Istituti Clinici Scientifici Maugeri, Lissone MB, Italy.
| | - Simona Ferrante
- Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy
| | - Mark van de Ruit
- Department of Biomechanical Engineering Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Stefano Biguzzi
- Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy
| | - Vera Colombo
- Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy
| | - Marco Monticone
- Department of Public Health, Clinical and Molecular Medicine, University of Cagliari, Cagliari, Italy
| | - Giorgio Ferriero
- Department of Physical and Rehabilitative Medicine, Scientific Institute of Lissone IRCCS, Istituti Clinici Scientifici Maugeri, Lissone MB, Italy
| | - Alessandra Pedrocchi
- Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy
| | - Giancarlo Ferrigno
- Neuroengineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy
| | - Michael J Grey
- Acquired Brain Injury Rehabilitation Alliance, School of Health Sciences, University of East Anglia, Norwich, United Kingdom
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Kesar TM, Eicholtz S, Lin BJ, Wolf SL, Borich MR. Effects of posture and coactivation on corticomotor excitability of ankle muscles. Restor Neurol Neurosci 2018; 36:131-146. [PMID: 29439363 PMCID: PMC5901671 DOI: 10.3233/rnn-170773] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The use of transcranial magnetic stimulation (TMS) to evaluate corticomotor excitability of lower limb (LL) muscles can provide insights about neuroplasticity mechanisms underlying LL rehabilitation. However, to date, a majority of TMS studies have focused on upper limb muscles. Posture-related activation is an important under-investigated factor influencing corticomotor excitability of LL muscles. OBJECTIVE The purpose of this study was to evaluate effects of posture and background activation on corticomotor excitability of ankle muscles. METHODS Fourteen young neurologically-unimpaired participants (26.1±4.1 years) completed the study. TMS-evoked motor evoked potentials (MEPs) were recorded from the tibialis anterior (TA) and soleus during 4 conditions - standing, standing coactivation, sitting, and sitting coactivation. TA and soleus MEP amplitudes were compared during: (1) standing versus sitting;(2) standing coactivation (standing while activating both TA and soleus) versus sitting coactivation; and (3) standing coactivation versus standing. For each comparison, background EMG for TA and soleus were matched. Trial-to-trial coefficient of variation of MEP amplitude and coil-positioning errors were additional dependent variables. RESULTS No differences were observed in TA or soleus MEP amplitudes during standing versus sitting. Compared to sitting coactivation, larger MEPs were observed during standing coactivation for soleus but not TA. Compared to standing, the standing coactivation task demonstrated larger MEPs and reduced trial-to-trial MEP variability. CONCLUSION Our findings suggest that incorporation of measurements in standing in future TMS studies may provide novel insights into neural circuits controlling LL muscles. Standing and standing coactivation tasks may be beneficial for obtaining functionally-relevant neuroplasticity assessments of LL musculature.
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Affiliation(s)
- Trisha M. Kesar
- Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA, USA
| | - Steven Eicholtz
- Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA, USA
| | - Bethany J. Lin
- Center for Visual and Neuro-cognitive Rehabilitation, Atlanta Veterans Affairs, Atlanta, GA, USA
| | - Steven L. Wolf
- Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA, USA
- Center for Visual and Neuro-cognitive Rehabilitation, Atlanta Veterans Affairs, Atlanta, GA, USA
| | - Michael R. Borich
- Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA, USA
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Peri E, Ambrosini E, Colombo VM, van de Ruit M, Grey MJ, Monticone M, Ferriero G, Pedrocchi A, Ferrigno G, Ferrante S. Intra and inter-session reliability of rapid Transcranial Magnetic Stimulation stimulus-response curves of tibialis anterior muscle in healthy older adults. PLoS One 2017; 12:e0184828. [PMID: 28910370 PMCID: PMC5599029 DOI: 10.1371/journal.pone.0184828] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/31/2017] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE The clinical use of Transcranial Magnetic Stimulation (TMS) as a technique to assess corticospinal excitability is limited by the time for data acquisition and the measurement variability. This study aimed at evaluating the reliability of Stimulus-Response (SR) curves acquired with a recently proposed rapid protocol on tibialis anterior muscle of healthy older adults. METHODS Twenty-four neurologically-intact adults (age:55-75 years) were recruited for this test-retest study. During each session, six SR curves, 3 at rest and 3 during isometric muscle contractions at 5% of maximum voluntary contraction (MVC), were acquired. Motor Evoked Potentials (MEPs) were normalized to the maximum peripherally evoked response; the coil position and orientation were monitored with an optical tracking system. Intra- and inter-session reliability of motor threshold (MT), area under the curve (AURC), MEPmax, stimulation intensity at which the MEP is mid-way between MEPmax and MEPmin (I50), slope in I50, MEP latency, and silent period (SP) were assessed in terms of Standard Error of Measurement (SEM), relative SEM, Minimum Detectable Change (MDC), and Intraclass Correlation Coefficient (ICC). RESULTS The relative SEM was ≤10% for MT, I50, latency and SP both at rest and 5%MVC, while it ranged between 11% and 37% for AURC, MEPmax, and slope. MDC values were overall quite large; e.g., MT required a change of 12%MSO at rest and 10%MSO at 5%MVC to be considered a real change. Inter-sessions ICC were >0.6 for all measures but slope at rest and MEPmax and latency at 5%MVC. CONCLUSIONS Measures derived from SR curves acquired in <4 minutes are affected by similar measurement errors to those found with long-lasting protocols, suggesting that the rapid method is at least as reliable as the traditional methods. As specifically designed to include older adults, this study provides normative data for future studies involving older neurological patients (e.g. stroke survivors).
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Affiliation(s)
- Elisabetta Peri
- NearLab, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
- * E-mail:
| | - Emilia Ambrosini
- NearLab, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
- Department of Physical and Rehabilitative Medicine, Scientific Institute of Lissone IRCCS, Istituti Clinici Scientifici Maugeri, Lissone, MB, Italy
| | - Vera Maria Colombo
- NearLab, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Mark van de Ruit
- Department of Biomechanical Engineering Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Michael J. Grey
- Acquired Brain Injury Rehabilitation Alliance, School of Health Sciences, University of East Anglia, Norwich, United Kingdom
| | - Marco Monticone
- Department of Physical and Rehabilitative Medicine, Scientific Institute of Lissone IRCCS, Istituti Clinici Scientifici Maugeri, Lissone, MB, Italy
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy
| | - Giorgio Ferriero
- Department of Physical and Rehabilitative Medicine, Scientific Institute of Lissone IRCCS, Istituti Clinici Scientifici Maugeri, Lissone, MB, Italy
| | - Alessandra Pedrocchi
- NearLab, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Giancarlo Ferrigno
- NearLab, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Simona Ferrante
- NearLab, Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
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Thut G, Bergmann TO, Fröhlich F, Soekadar SR, Brittain JS, Valero-Cabré A, Sack AT, Miniussi C, Antal A, Siebner HR, Ziemann U, Herrmann CS. Guiding transcranial brain stimulation by EEG/MEG to interact with ongoing brain activity and associated functions: A position paper. Clin Neurophysiol 2017; 128:843-857. [PMID: 28233641 DOI: 10.1016/j.clinph.2017.01.003] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 12/10/2016] [Accepted: 01/08/2017] [Indexed: 01/31/2023]
Abstract
Non-invasive transcranial brain stimulation (NTBS) techniques have a wide range of applications but also suffer from a number of limitations mainly related to poor specificity of intervention and variable effect size. These limitations motivated recent efforts to focus on the temporal dimension of NTBS with respect to the ongoing brain activity. Temporal patterns of ongoing neuronal activity, in particular brain oscillations and their fluctuations, can be traced with electro- or magnetoencephalography (EEG/MEG), to guide the timing as well as the stimulation settings of NTBS. These novel, online and offline EEG/MEG-guided NTBS-approaches are tailored to specifically interact with the underlying brain activity. Online EEG/MEG has been used to guide the timing of NTBS (i.e., when to stimulate): by taking into account instantaneous phase or power of oscillatory brain activity, NTBS can be aligned to fluctuations in excitability states. Moreover, offline EEG/MEG recordings prior to interventions can inform researchers and clinicians how to stimulate: by frequency-tuning NTBS to the oscillation of interest, intrinsic brain oscillations can be up- or down-regulated. In this paper, we provide an overview of existing approaches and ideas of EEG/MEG-guided interventions, and their promises and caveats. We point out potential future lines of research to address challenges.
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Affiliation(s)
- Gregor Thut
- Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK.
| | - Til Ole Bergmann
- Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, Institute for Medical Psychology and Behavioral Neurobiology, University Hospital Tübingen, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Flavio Fröhlich
- Department of Psychiatry & Department of Biomedical Engineering & Department of Cell Biology and Physiology & Neuroscience Center & Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Surjo R Soekadar
- Applied Neurotechnology Lab, Department of Psychiatry and Psychotherapy & MEG Center, University Hospital of Tübingen, Tübingen, Germany
| | - John-Stuart Brittain
- Nuffield Department of Clinical Neurosciences, Charles Wolfson Neuroscience Clinical Research Facility, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Antoni Valero-Cabré
- Cerebral Dynamics, Plasticity and Rehabilitation Group, Frontlab, Institut du Cerveau et la Moelle (ICM), CNRS UMR 7225-INSERM U-117, Université Pierre et Marie Curie, Paris, France
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Carlo Miniussi
- Center for Mind/Brain Sciences CIMeC University of Trento, Rovereto, Italy & Cognitive Neuroscience Section, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center, Göttingen, Germany
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark
| | - Ulf Ziemann
- Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, University Tübingen, Tübingen, Germany
| | - Christoph S Herrmann
- Experimental Psychology Lab, Department of Psychology, Center for Excellence "Hearing4all", European Medical School, Carl von Ossietzky University & Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
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Washabaugh EP, Krishnan C. A low-cost system for coil tracking during transcranial magnetic stimulation. Restor Neurol Neurosci 2016; 34:337-46. [PMID: 26923620 DOI: 10.3233/rnn-150609] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE Accurate coil placement over a target area is critical during transcranial magnetic stimulation (TMS), as small deviations can alter testing outcomes. Accordingly, frameless stereotaxic systems (FSS) are recommended for reliable coil placement during TMS applications. However, FSS is not practical due to the cost associated with procuring such systems. Therefore, the purpose of this study was to develop a low-cost TMS coil tracking approach using simple webcams and an image processing algorithm in LabVIEW Vision Assistant. METHODS A system was created using two webcams, retroreflective markers, and computer stereovision, for tracking the TMS coil over a target area. Accuracy of the system was validated in both the global and local reference frames, while repeatability was measured within- and between-days for placement of the TMS coil over the target area relative to the head. The feasibility of our system was also verified by collecting motor evoked potentials (MEPs) of first dorsal interosseous muscle from human subjects. RESULTS The results of this study indicated that the system was highly accurate and repeatable, and could track the coil position with <5 mm error and orientation <1.1° error from the target. We also observed larger and more consistent MEPs when stimulating the brain using feedback from the coil tracking system than when the examiner attempted to stimulate without any feedback. CONCLUSION The findings suggest that webcam-based coil tracking is a feasible low-cost solution to track coil positions during TMS procedures.
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Affiliation(s)
- Edward P Washabaugh
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Chandramouli Krishnan
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA.,School of Kinesiology, University of Michigan, Ann Arbor, MI, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
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Sollmann N, Goblirsch-Kolb MF, Ille S, Butenschoen VM, Boeckh-Behrens T, Meyer B, Ringel F, Krieg SM. Comparison between electric-field-navigated and line-navigated TMS for cortical motor mapping in patients with brain tumors. Acta Neurochir (Wien) 2016; 158:2277-2289. [PMID: 27722947 DOI: 10.1007/s00701-016-2970-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 09/12/2016] [Indexed: 01/24/2023]
Abstract
BACKGROUND For the navigation of transcranial magnetic stimulation (TMS), various techniques are available. Yet, there are two basic principles underlying them all: electric-field-navigated transcranial magnetic stimulation (En-TMS) and line-navigated transcranial magnetic stimulation (Ln-TMS). The current study was designed to compare both methods. METHODS To explore whether there is a difference in clinical applicability, workflow, and mapping results of both techniques, we systematically compared motor mapping via En-TMS and Ln-TMS in 12 patients suffering from brain tumors. RESULTS The number of motor-positive stimulation spots and the ratio of positive spots per overall stimulation numbers were significantly higher for En-TMS (motor-positive spots: En-TMS vs. Ln-TMS: 128.3 ± 35.0 vs. 41.3 ± 26.8, p < 0.0001; ratio of motor-positive spots per number of stimulations: En-TMS vs. Ln-TMS: 38.0 ± 9.2 % vs. 20.0 ± 14.4 %, p = 0.0031). Distances between the En-TMS and Ln-TMS motor hotspots were 8.3 ± 4.4 mm on the ipsilesional and 8.6 ± 4.5 mm on the contralesional hemisphere (p = 0.9124). CONCLUSIONS The present study compares En-TMS and Ln-TMS motor mapping in the neurosurgical context for the first time. Although both TMS systems tested in the present study are explicitly designed for application during motor mapping in patients with brain lesions, there are differences in applicability, workflow, and results between En-TMS and Ln-TMS, which should be distinctly considered during clinical use of the technique. However, to draw final conclusions about accuracy, confirmation of motor-positive Ln-TMS spots by intraoperative stimulation is crucial within the scope of upcoming investigations.
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Clinical Factors Underlying the Inter-individual Variability of the Resting Motor Threshold in Navigated Transcranial Magnetic Stimulation Motor Mapping. Brain Topogr 2016; 30:98-121. [PMID: 27815647 DOI: 10.1007/s10548-016-0536-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 10/26/2016] [Indexed: 10/20/2022]
Abstract
Correctly determining individual's resting motor threshold (rMT) is crucial for accurate and reliable mapping by navigated transcranial magnetic stimulation (nTMS), which is especially true for preoperative motor mapping in brain tumor patients. However, systematic data analysis on clinical factors underlying inter-individual rMT variability in neurosurgical motor mapping is sparse. The present study examined 14 preselected clinical factors that may underlie inter-individual rMT variability by performing multiple regression analysis (backward, followed by forward model comparisons) on the nTMS motor mapping data of 100 brain tumor patients. Data were collected from preoperative motor mapping of abductor pollicis brevis (APB), abductor digiti minimi (ADM), and flexor carpi radialis (FCR) muscle representations among these patients. While edema and age at exam in the ADM model only jointly reduced the unexplained variance significantly, the other factors kept in the ADM model (gender, antiepileptic drug intake, and motor deficit) and each of the factors kept in the APB and FCR models independently significantly reduced the unexplained variance. Hence, several clinical parameters contribute to inter-individual rMT variability and should be taken into account during initial and follow-up motor mappings. Thus, the present study adds basic evidence on inter-individual rMT variability, whereby some of the parameters are specific to brain tumor patients.
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Neuromuscular Plasticity: Disentangling Stable and Variable Motor Maps in the Human Sensorimotor Cortex. Neural Plast 2016; 2016:7365609. [PMID: 27610248 PMCID: PMC5004060 DOI: 10.1155/2016/7365609] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/28/2016] [Accepted: 07/19/2016] [Indexed: 02/02/2023] Open
Abstract
Motor maps acquired with transcranial magnetic stimulation (TMS) are evolving as a biomarker for monitoring disease progression or the effects of therapeutic interventions. High test-retest reliability of this technique for long observation periods is therefore required to differentiate daily or weekly fluctuations from stable plastic reorganization of corticospinal connectivity. In this study, a novel projection, interpolation, and coregistration technique, which considers the individual gyral anatomy, was applied in healthy subjects for biweekly acquired TMS motor maps over a period of twelve weeks. The intraclass correlation coefficient revealed long-term reliability of motor maps with relevant interhemispheric differences. The sensorimotor cortex and nonprimary motor areas of the dominant hemisphere showed more extended and more stable corticospinal connectivity. Long-term correlations of the MEP amplitudes at each stimulation site revealed mosaic-like clusters of consistent corticospinal excitability. The resting motor threshold, centre of gravity, and mean MEPs across all TMS sites, as highly reliable cortical map parameters, could be disentangled from more variable parameters such as MEP area and volume. Cortical TMS motor maps provide high test-retest reliability for long-term monitoring when analyzed with refined techniques. They may guide restorative interventions which target dormant corticospinal connectivity for neurorehabilitation.
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Julkunen P, Määttä S, Säisänen L, Kallioniemi E, Könönen M, Jäkälä P, Vanninen R, Vaalto S. Functional and structural cortical characteristics after restricted focal motor cortical infarction evaluated at chronic stage - Indications from a preliminary study. Clin Neurophysiol 2016; 127:2775-2784. [PMID: 27417053 DOI: 10.1016/j.clinph.2016.05.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 05/04/2016] [Accepted: 05/10/2016] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To assess the inter-hemispheric differences in neuronal function and structure of the motor cortex in a small group of chronic stroke patients having suffered a restricted ischemic lesion affecting hand motor representation. GABAergic intracortical inhibition, known to be affected by stroke lesion, was also investigated. METHODS Eight patients exhibiting little or no motor impairment were studied using transcranial magnetic stimulation (TMS) and diffusion weighted imaging (DWI) >15months from diagnosis. Resting motor threshold (MT) for 50μV and 2mV motor evoked potentials, and short-interval intracortical inhibition (SICI) were measured from hand muscles. Apparent diffusion coefficients (ADCs) were analyzed from the DWI for the primary motor cortex (M1), the supplementary motor area (SMA) and thalamus for reflecting changes in neuronal organization. RESULTS The MTs did not differ between the affected (AH) and unaffected hemisphere (UH) in 50μV responses, while the MTs for 2mV responses were higher (p=0.018) in AH. SICI was weakened in AH (p=0.008). ADCs were higher in the affected M1 compared to the unaffected M1 (p=0.018) while there were no inter-hemispheric differences in SMA or thalamus. CONCLUSIONS Inter-hemispheric asymmetry and neuronal organization demonstrated abnormalities in the M1. However, no confident inference can be made whether the observed alterations in neurophysiological and imaging measures have causal role for motor rehabilitation in these patients. SIGNIFICANCE Neurophysiological changes persist and are detectable using TMS years after stroke even though clinical symptoms have normalized.
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Affiliation(s)
- Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - Sara Määttä
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Clinical Neurophysiology, Institute of Clinical Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Laura Säisänen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Clinical Neurophysiology, Institute of Clinical Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Elisa Kallioniemi
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Mervi Könönen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland
| | - Pekka Jäkälä
- Department of Neurology, Kuopio University Hospital, Kuopio, Finland; Department of Neurology, Institute of Clinical Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Ritva Vanninen
- Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland; Department of Clinical Radiology, Institute of Clinical Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Selja Vaalto
- Department of Clinical Neurophysiology, Helsinki University Hospital, Helsinki, Finland; Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
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Goldsworthy M, Hordacre B, Ridding M. Minimum number of trials required for within- and between-session reliability of TMS measures of corticospinal excitability. Neuroscience 2016; 320:205-9. [DOI: 10.1016/j.neuroscience.2016.02.012] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/02/2016] [Accepted: 02/02/2016] [Indexed: 11/30/2022]
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Ahdab R, Ayache SS, Brugières P, Farhat WH, Lefaucheur JP. The Hand Motor Hotspot is not Always Located in the Hand Knob: A Neuronavigated Transcranial Magnetic Stimulation Study. Brain Topogr 2016; 29:590-7. [PMID: 26980192 DOI: 10.1007/s10548-016-0486-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
Abstract
The hand motor hot spot (hMHS) is one of the most salient parameters in transcranial magnetic stimulation (TMS) practice, notably used for targeting. It is commonly accepted that the hMHS corresponds to the hand representation within the primary motor cortex (M1). Anatomical and imaging studies locate this representation in a region of the central sulcus called the "hand knob". The aim of this study was to determine if the hMHS location corresponds to its expected location at the hand knob. Twelve healthy volunteers and eleven patients with chronic neuropathic pain of various origins, but not related to a brain lesion, were enrolled. Morphological magnetic resonance imaging of the brain was normal in all participants. Both hemispheres were studied in all participants except four (two patients and two healthy subjects). Cortical mapping of the hand motor area was conducted using a TMS-dedicated navigation system and recording motor evoked potentials (MEPs) in the contralateral first dorsal interosseous (FDI) muscle. We then determined the anatomical position of the hMHS, defined as the stimulation site providing the largest FDI-MEPs. In 45 % of hemispheres of normal subjects and 25 % of hemispheres of pain patients, the hMHS was located over the central sulcus, most frequently at the level of the hand knob. However, in the other cases, the hMHS was located outside M1, most frequently anteriorly over the precentral or middle frontal gyrus. This study shows that the hMHS does not always correspond to the hand knob and M1 location in healthy subjects or patients. Therefore, image-guided navigation is needed to improve the anatomical accuracy of TMS targeting, even for M1.
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Affiliation(s)
- Rechdi Ahdab
- EA 4391, Excitabilité Nerveuse et Thérapeutique, Université Paris-Est-Créteil, Créteil, France.,Service de Physiologie - Explorations Fonctionnelles, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris, 51 avenue de Lattre de Tassigny, 94010, Créteil, France.,Neurology Division, University Medical Center Rizk Hospital, Beirut, Lebanon
| | - Samar S Ayache
- EA 4391, Excitabilité Nerveuse et Thérapeutique, Université Paris-Est-Créteil, Créteil, France. .,Service de Physiologie - Explorations Fonctionnelles, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris, 51 avenue de Lattre de Tassigny, 94010, Créteil, France. .,Neurology Division, University Medical Center Rizk Hospital, Beirut, Lebanon.
| | - Pierre Brugières
- Service de Neuroradiologie, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris, Créteil, France
| | - Wassim H Farhat
- EA 4391, Excitabilité Nerveuse et Thérapeutique, Université Paris-Est-Créteil, Créteil, France.,Service de Physiologie - Explorations Fonctionnelles, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris, 51 avenue de Lattre de Tassigny, 94010, Créteil, France
| | - Jean-Pascal Lefaucheur
- EA 4391, Excitabilité Nerveuse et Thérapeutique, Université Paris-Est-Créteil, Créteil, France.,Service de Physiologie - Explorations Fonctionnelles, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris, 51 avenue de Lattre de Tassigny, 94010, Créteil, France
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Meincke J, Hewitt M, Batsikadze G, Liebetanz D. Automated TMS hotspot-hunting using a closed loop threshold-based algorithm. Neuroimage 2016; 124:509-517. [DOI: 10.1016/j.neuroimage.2015.09.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/28/2015] [Accepted: 09/07/2015] [Indexed: 01/30/2023] Open
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Kallioniemi E, Könönen M, Säisänen L, Gröhn H, Julkunen P. Functional neuronal anisotropy assessed with neuronavigated transcranial magnetic stimulation. J Neurosci Methods 2015; 256:82-90. [PMID: 26335800 DOI: 10.1016/j.jneumeth.2015.08.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 08/02/2015] [Accepted: 08/25/2015] [Indexed: 01/28/2023]
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) can evaluate cortical excitability and integrity of motor pathways via TMS-induced responses. The responses are affected by the orientation of the stimulated neurons with respect to the direction of the TMS-induced electric field. Therefore, besides being a functional imaging tool, TMS may potentially assess the local structural properties. Yet, TMS has not been used for this purpose. NEW METHOD A novel principle to evaluate the relation between function and structure of the motor cortex is presented. This functional anisotropy is evaluated by an anisotropy index (AI), based on motor evoked potential amplitudes induced with different TMS coil orientations, i.e. different electric field directions at a cortical target. To compare the AI with anatomical anisotropy in an explorative manner, diffusion tensor imaging-derived fractional anisotropy (FA) was estimated at different depths near the stimulation site. RESULTS AI correlated inversely with cortical excitability through the TMS-induced electric field at motor threshold level. Further, there was a trend of negative correlation between AI and FA. COMPARISON WITH EXISTING METHODS None of the existing methods alone can detect the relationship between direct motor cortex activation and local neuronal structure. CONCLUSIONS The AI appears to provide information on the functional neuronal anisotropy of the motor cortex by coupling neurophysiology and neuroanatomy within the stimulated cortical region. The AI could prove useful in the evaluation of neurological disorders and traumas involving concurrent structural and functional changes in the motor cortex. Further studies on patients are needed to confirm the usability of AI.
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Affiliation(s)
- Elisa Kallioniemi
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland; Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
| | - Mervi Könönen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland; Department of Clinical Radiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Laura Säisänen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland; Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland
| | - Heidi Gröhn
- Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland; Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland
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