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Ailion A, Duong P, Maiman M, Tsuboyama M, Smith ML. Clinical recommendations for conducting pediatric functional language and memory mapping during the phase I epilepsy presurgical workup. Clin Neuropsychol 2024; 38:1060-1084. [PMID: 37985747 DOI: 10.1080/13854046.2023.2281708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 11/02/2023] [Indexed: 11/22/2023]
Abstract
Objective: Pediatric epilepsy surgery effectively controls seizures but may risk cognitive, language, or memory decline. Historically, the intra-carotid anesthetic procedure (IAP or Wada Test) was pivotal for language and memory function. However, advancements in noninvasive mapping, notably functional magnetic resonance imaging (fMRI), have transformed clinical practice, reducing IAP's role in presurgical evaluations. Method: We conducted a critical narrative review on mapping technologies, including factors to consider for discordance. Results: Neuropsychological findings suggest that if pre-surgery function remains intact and the surgery targets the eloquent cortex, there is a high chance for decline. Memory and language decline are particularly pronounced post-left anterior temporal lobe resection (ATL), making presurgical cognitive assessment crucial for predicting postoperative outcomes. However, the risk of functional decline is not always clear - particularly with higher rates of atypical organization in pediatric epilepsy patients and discordant findings from cognitive mapping. We found little research to date on the use of IAP and other newer technologies for lateralization/localization in pediatric epilepsy. Based on this review, we introduce an IAP decision tree to systematically navigate discordance in IAP decisions for epilepsy presurgical workup. Conclusions: Future research should be aimed at pediatric populations to improve the precision of functional mapping, determine which methods predict post-surgical deficits and then create evidence-based practice guidelines to standardize mapping procedures. Explicit directives are needed for resolving conflicts between developing mapping procedures and established clinical measures. The proposed decision tree is the first step to standardize when to consider IAP or invasive mapping, in coordination with the multidisciplinary epilepsy surgical team.
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Affiliation(s)
- Alyssa Ailion
- Department of Psychiatry, Boston Children's Hospital, Harvard Medical School
- Department of Neurology, Boston Children's Hospital, Harvard Medical School
| | - Priscilla Duong
- Department of Psychiatry, Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University School of Medicine
| | - Moshe Maiman
- Department of Psychiatry, Boston Children's Hospital, Harvard Medical School
| | - Melissa Tsuboyama
- Department of Neurology, Boston Children's Hospital, Harvard Medical School
| | - Mary Lou Smith
- Department of Psychology, The Hospital for Sick Children, University of Toronto Mississauga
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Dmytriw AA, Hadjinicolaou A, Ntolkeras G, Tamilia E, Pesce M, Berto LF, Grant PE, Pang E, Ahtam B. Magnetoencephalography for the pediatric population, indications, acquisition and interpretation for the clinician. Neuroradiol J 2024:19714009241260801. [PMID: 38864180 DOI: 10.1177/19714009241260801] [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: 06/13/2024] Open
Abstract
Magnetoencephalography (MEG) is an imaging technique that enables the assessment of cortical activity via direct measures of neurophysiology. It is a non-invasive and passive technique that is completely painless. MEG has gained increasing prominence in the field of pediatric neuroimaging. This dedicated review article for the pediatric population summarizes the fundamental technical and clinical aspects of MEG for the clinician. We discuss methods tailored for children to improve data quality, including child-friendly MEG facility environments and strategies to mitigate motion artifacts. We provide an in-depth overview on accurate localization of neural sources and different analysis methods, as well as data interpretation. The contemporary platforms and approaches of two quaternary pediatric referral centers are illustrated, shedding light on practical implementations in clinical settings. Finally, we describe the expanding clinical applications of MEG, including its pivotal role in presurgical evaluation of epilepsy patients, presurgical mapping of eloquent cortices (somatosensory and motor cortices, visual and auditory cortices, lateralization of language), its emerging relevance in autism spectrum disorder research and potential future clinical applications, and its utility in assessing mild traumatic brain injury. In conclusion, this review serves as a comprehensive resource of clinicians as well as researchers, offering insights into the evolving landscape of pediatric MEG. It discusses the importance of technical advancements, data acquisition strategies, and expanding clinical applications in harnessing the full potential of MEG to study neurological conditions in the pediatric population.
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Affiliation(s)
- Adam A Dmytriw
- Department of Radiology, Boston Children's Hospital, Boston, MA, USA
- Division of Neuroradiology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Aristides Hadjinicolaou
- Division of Neurology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, USA
| | - Georgios Ntolkeras
- Department of Pediatrics, Division of Newborn Medicine, Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Boston, MA, USA
| | - Eleonora Tamilia
- Department of Pediatrics, Division of Newborn Medicine, Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Boston, MA, USA
| | - Matthew Pesce
- Department of Pediatrics, Division of Newborn Medicine, Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Boston, MA, USA
| | - Laura F Berto
- Department of Pediatrics, Division of Newborn Medicine, Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Boston, MA, USA
| | - P Ellen Grant
- Department of Radiology, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Division of Newborn Medicine, Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Boston, MA, USA
| | - Elizabeth Pang
- Division of Neurology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Banu Ahtam
- Department of Pediatrics, Division of Newborn Medicine, Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Boston, MA, USA
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Kochi R, Osawa SI, Jin K, Ishida M, Kanno A, Iwasaki M, Suzuki K, Kawashima R, Tominaga T, Nakasato N. Language MEG predicts postoperative verbal memory change in left mesial temporal lobe epilepsy. Clin Neurophysiol 2023; 156:69-75. [PMID: 37890232 DOI: 10.1016/j.clinph.2023.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 08/28/2023] [Accepted: 09/05/2023] [Indexed: 10/29/2023]
Abstract
OBJECTIVE To clarify whether preoperative language magnetoencephalography (MEG) predicts postoperative verbal memory (VM) changes in left mesial temporal lobe epilepsy (LMTLE). METHODS We reviewed 18 right-handed patients with LMTLE who underwent anterior temporal lobectomy or selective amygdala hippocampectomy, 12 with (HS+) and 6 without hippocampal sclerosis (HS-). Patients underwent neuropsychological assessment before and after surgery. MEG was measured with an auditory verbal learning task in patients preoperatively and in 15 right-handed controls. Dynamic statistical parametric mapping (dSPM) was used for source imaging of task-related activity. Language laterality index (LI) was calculated by z-score of dSPM in language-related regions. LI in the region of HS+ and HS- was compared to controls. The correlation between LI and postoperative VM change was assessed in HS+ and HS-. RESULTS Preoperative LI in supramarginal gyrus showed greater right-shifted lateralization in both HS+ and HS- than in controls. Right-shifted LI in supramarginal gyrus was correlated with postoperative VM increase in HS+ (p = 0.019), but not in HS-. CONCLUSIONS Right-shifted language lateralization in dSPM of MEG signals may predict favorable VM outcome in HS+ of LMTLE. SIGNIFICANCE Findings warrant further investigation of the relation between regional language laterality index and postoperative verbal memory changes.
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Affiliation(s)
- Ryuzaburo Kochi
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Shin-Ichiro Osawa
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kazutaka Jin
- Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
| | - Makoto Ishida
- Department of Advanced Spintronics Medical Engineering, Tohoku University Graduate School of Engineering, Sendai, Miyagi, Japan
| | - Akitake Kanno
- Department of Advanced Spintronics Medical Engineering, Tohoku University Graduate School of Engineering, Sendai, Miyagi, Japan
| | - Masaki Iwasaki
- Department of Neurosurgery, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Kyoko Suzuki
- Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Ryuta Kawashima
- Department of Functional Brain Imaging, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, Japan
| | - Teiji Tominaga
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Nobukazu Nakasato
- Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan; Department of Advanced Spintronics Medical Engineering, Tohoku University Graduate School of Engineering, Sendai, Miyagi, Japan
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4
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Papanicolaou AC. Non-Invasive Mapping of the Neuronal Networks of Language. Brain Sci 2023; 13:1457. [PMID: 37891824 PMCID: PMC10605023 DOI: 10.3390/brainsci13101457] [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: 08/07/2023] [Revised: 09/13/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
This review consists of three main sections. In the first, the Introduction, the main theories of the neuronal mediation of linguistic operations, derived mostly from studies of the effects of focal lesions on linguistic performance, are summarized. These models furnish the conceptual framework on which the design of subsequent functional neuroimaging investigations is based. In the second section, the methods of functional neuroimaging, especially those of functional Magnetic Resonance Imaging (fMRI) and of Magnetoencephalography (MEG), are detailed along with the specific activation tasks employed in presurgical functional mapping. The reliability of these non-invasive methods and their validity, judged against the results of the invasive methods, namely, the "Wada" procedure and Cortical Stimulation Mapping (CSM), is assessed and their use in presurgical mapping is justified. In the third and final section, the applications of fMRI and MEG in basic research are surveyed in the following six sub-sections, each dealing with the assessment of the neuronal networks for (1) the acoustic and phonological, (2) for semantic, (3) for syntactic, (4) for prosodic operations, (5) for sign language and (6) for the operations of reading and the mechanisms of dyslexia.
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Affiliation(s)
- Andrew C Papanicolaou
- Department of Pediatrics, Division of Pediatric Neurology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38013, USA
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5
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Babajani-Feremi A, Pourmotabbed H, Schraegle WA, Calley CS, Clarke DF, Papanicolaou AC. MEG language mapping using a novel automatic ECD algorithm in comparison with MNE, dSPM, and DICS beamformer. Front Neurosci 2023; 17:1151885. [PMID: 37332870 PMCID: PMC10272516 DOI: 10.3389/fnins.2023.1151885] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/24/2023] [Indexed: 06/20/2023] Open
Abstract
Introduction The single equivalent current dipole (sECD) is the standard clinical procedure for presurgical language mapping in epilepsy using magnetoencephalography (MEG). However, the sECD approach has not been widely used in clinical assessments, mainly because it requires subjective judgements in selecting several critical parameters. To address this limitation, we developed an automatic sECD algorithm (AsECDa) for language mapping. Methods The localization accuracy of the AsECDa was evaluated using synthetic MEG data. Subsequently, the reliability and efficiency of AsECDa were compared to three other common source localization methods using MEG data recorded during two sessions of a receptive language task in 21 epilepsy patients. These methods include minimum norm estimation (MNE), dynamic statistical parametric mapping (dSPM), and dynamic imaging of coherent sources (DICS) beamformer. Results For the synthetic single dipole MEG data with a typical signal-to-noise ratio, the average localization error of AsECDa was less than 2 mm for simulated superficial and deep dipoles. For the patient data, AsECDa showed better test-retest reliability (TRR) of the language laterality index (LI) than MNE, dSPM, and DICS beamformer. Specifically, the LI calculated with AsECDa revealed excellent TRR between the two MEG sessions across all patients (Cor = 0.80), while the LI for MNE, dSPM, DICS-event-related desynchronization (ERD) in the alpha band, and DICS-ERD in the low beta band ranged lower (Cor = 0.71, 0.64, 0.54, and 0.48, respectively). Furthermore, AsECDa identified 38% of patients with atypical language lateralization (i.e., right lateralization or bilateral), compared to 73%, 68%, 55%, and 50% identified by DICS-ERD in the low beta band, DICS-ERD in the alpha band, MNE, and dSPM, respectively. Compared to other methods, AsECDa's results were more consistent with previous studies that reported atypical language lateralization in 20-30% of epilepsy patients. Discussion Our study suggests that AsECDa is a promising approach for presurgical language mapping, and its fully automated nature makes it easy to implement and reliable for clinical evaluations.
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Affiliation(s)
- Abbas Babajani-Feremi
- Department of Neurology, University of Florida, Gainesville, FL, United States
- Magnetoencephalography (MEG) Lab, The Norman Fixel Institute of Neurological Diseases, University of Florida Health, Gainesville, FL, United States
- Department of Neurology, Dell Medical School, University of Texas at Austin, Austin, TX, United States
| | - Haatef Pourmotabbed
- Department of Neurology, Dell Medical School, University of Texas at Austin, Austin, TX, United States
| | - William A. Schraegle
- Department of Neurology, Dell Medical School, University of Texas at Austin, Austin, TX, United States
- Comprehensive Pediatric Epilepsy Center, Dell Children’s Medical Center, Austin, TX, United States
- Department of Pediatrics, Dell Medical School, University of Texas at Austin, Austin, TX, United States
| | - Clifford S. Calley
- Department of Neurology, Dell Medical School, University of Texas at Austin, Austin, TX, United States
- Comprehensive Pediatric Epilepsy Center, Dell Children’s Medical Center, Austin, TX, United States
- Department of Pediatrics, Dell Medical School, University of Texas at Austin, Austin, TX, United States
- Department of Neurosurgery, Dell Medical School, University of Texas at Austin, Austin, TX, United States
| | - Dave F. Clarke
- Department of Neurology, Dell Medical School, University of Texas at Austin, Austin, TX, United States
- Comprehensive Pediatric Epilepsy Center, Dell Children’s Medical Center, Austin, TX, United States
- Department of Pediatrics, Dell Medical School, University of Texas at Austin, Austin, TX, United States
- Department of Neurosurgery, Dell Medical School, University of Texas at Austin, Austin, TX, United States
| | - Andrew C. Papanicolaou
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, United States
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Herfurth K, Harpaz Y, Roesch J, Mueller N, Walther K, Kaltenhaeuser M, Pauli E, Goldstein A, Hamer H, Buchfelder M, Doerfler A, Prell J, Rampp S. Localization of beta power decrease as measure for lateralization in pre-surgical language mapping with magnetoencephalography, compared with functional magnetic resonance imaging and validated by Wada test. Front Hum Neurosci 2022; 16:996989. [PMID: 36393988 PMCID: PMC9644652 DOI: 10.3389/fnhum.2022.996989] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/04/2022] [Indexed: 11/04/2023] Open
Abstract
Objective: Atypical patterns of language lateralization due to early reorganizational processes constitute a challenge in the pre-surgical evaluation of patients with pharmaco-resistant epilepsy. There is no consensus on an optimal analysis method used for the identification of language dominance in MEG. This study examines the concordance between MEG source localization of beta power desynchronization and fMRI with regard to lateralization and localization of expressive and receptive language areas using a visual verb generation task. Methods: Twenty-five patients with pharmaco-resistant epilepsy, including six patients with atypical language lateralization, and ten right-handed controls obtained MEG and fMRI language assessment. Fourteen patients additionally underwent the Wada test. We analyzed MEG beta power desynchronization in sensor (controls) and source space (patients and controls). Beta power decrease between 13 and 35 Hz was localized applying Dynamic Imaging of Coherent Sources Beamformer technique. Statistical inferences were grounded on cluster-based permutation testing for single subjects. Results: Event-related desynchronization of beta power in MEG was seen within the language-dominant frontal and temporal lobe and within the premotor cortex. Our analysis pipeline consistently yielded left language dominance with high laterality indices in controls. Language lateralization in MEG and Wada test agreed in all 14 patients for inferior frontal, temporal and parietal language areas (Cohen's Kappa = 1, p < 0.001). fMRI agreed with Wada test in 12 out of 14 cases (85.7%) for Broca's area (Cohen's Kappa = 0.71, p = 0.024), while the agreement for temporal and temporo-parietal language areas were non-significant. Concordance between MEG and fMRI laterality indices was highest within the inferior frontal gyrus, with an agreement in 19/24 cases (79.2%), and non-significant for Wernicke's area. Spatial agreement between fMRI and MEG varied considerably between subjects and brain regions with the lowest Euclidean distances within the inferior frontal region of interest. Conclusion: Localizing the desynchronization of MEG beta power using a verb generation task is a promising tool for the identification of language dominance in the pre-surgical evaluation of epilepsy patients. The overall agreement between MEG and fMRI was lower than expected and might be attributed to differences within the baseline condition. A larger sample size and an adjustment of the experimental designs are needed to draw further conclusions.
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Affiliation(s)
- Kirsten Herfurth
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
- Department of Neurosurgery, University Hospital Halle, Halle (Saale), Germany
| | - Yuval Harpaz
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
| | - Julie Roesch
- Department of Neuroradiology, University Hospital Erlangen, Erlangen, Germany
| | - Nadine Mueller
- Epilepsy Center, Department of Neurology, University Hospital Erlangen, Erlangen, Germany
| | - Katrin Walther
- Epilepsy Center, Department of Neurology, University Hospital Erlangen, Erlangen, Germany
| | | | - Elisabeth Pauli
- Epilepsy Center, Department of Neurology, University Hospital Erlangen, Erlangen, Germany
| | - Abraham Goldstein
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
| | - Hajo Hamer
- Epilepsy Center, Department of Neurology, University Hospital Erlangen, Erlangen, Germany
| | - Michael Buchfelder
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
| | - Arnd Doerfler
- Department of Neuroradiology, University Hospital Erlangen, Erlangen, Germany
| | - Julian Prell
- Department of Neurosurgery, University Hospital Halle, Halle (Saale), Germany
| | - Stefan Rampp
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
- Department of Neurosurgery, University Hospital Halle, Halle (Saale), Germany
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Trébuchon A, Liégeois-Chauvel C, Gonzalez-Martinez JA, Alario FX. Contributions of electrophysiology for identifying cortical language systems in patients with epilepsy. Epilepsy Behav 2020; 112:107407. [PMID: 33181892 DOI: 10.1016/j.yebeh.2020.107407] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/10/2020] [Accepted: 08/10/2020] [Indexed: 11/26/2022]
Abstract
A crucial element of the surgical treatment of medically refractory epilepsy is to delineate cortical areas that must be spared in order to avoid clinically relevant neurological and neuropsychological deficits postoperatively. For each patient, this typically necessitates determining the language lateralization between hemispheres and language localization within hemisphere. Understanding cortical language systems is complicated by two primary challenges: the extent of the neural tissue involved and the substantial variability across individuals, especially in pathological populations. We review the contributions made through the study of electrophysiological activity to address these challenges. These contributions are based on the techniques of magnetoencephalography (MEG), intracerebral recordings, electrical-cortical stimulation (ECS), and the electrovideo analyses of seizures and their semiology. We highlight why no single modality alone is adequate to identify cortical language systems and suggest avenues for improving current practice.
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Affiliation(s)
- Agnès Trébuchon
- Aix-Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Catherine Liégeois-Chauvel
- Aix-Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France; Department of Neurological Surgery, School of Medicine, University of Pittsburgh (PA), USA
| | | | - F-Xavier Alario
- Department of Neurological Surgery, School of Medicine, University of Pittsburgh (PA), USA; Aix-Marseille Univ, CNRS, LPC, Marseille, France.
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Bowyer SM, Zillgitt A, Greenwald M, Lajiness-O'Neill R. Language Mapping With Magnetoencephalography: An Update on the Current State of Clinical Research and Practice With Considerations for Clinical Practice Guidelines. J Clin Neurophysiol 2020; 37:554-563. [DOI: 10.1097/wnp.0000000000000489] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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9
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Youssofzadeh V, Stout J, Ustine C, Gross WL, Conant LL, Humphries CJ, Binder JR, Raghavan M. Mapping language from MEG beta power modulations during auditory and visual naming. Neuroimage 2020; 220:117090. [DOI: 10.1016/j.neuroimage.2020.117090] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/06/2020] [Accepted: 06/23/2020] [Indexed: 01/22/2023] Open
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10
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Hinkley LBN, De Witte E, Cahill-Thompson M, Mizuiri D, Garrett C, Honma S, Findlay A, Gorno-Tempini ML, Tarapore P, Kirsch HE, Mariën P, Houde JF, Berger M, Nagarajan SS. Optimizing Magnetoencephalographic Imaging Estimation of Language Lateralization for Simpler Language Tasks. Front Hum Neurosci 2020; 14:105. [PMID: 32499685 PMCID: PMC7242765 DOI: 10.3389/fnhum.2020.00105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 03/09/2020] [Indexed: 12/13/2022] Open
Abstract
Magnetoencephalographic imaging (MEGI) offers a non-invasive alternative for defining preoperative language lateralization in neurosurgery patients. MEGI indeed can be used for accurate estimation of language lateralization with a complex language task - auditory verb generation. However, since language function may vary considerably in patients with focal lesions, it is important to optimize MEGI for estimation of language function with other simpler language tasks. The goal of this study was to optimize MEGI laterality analyses for two such simpler language tasks that can have compliance from those with impaired language function: a non-word repetition (NWR) task and a picture naming (PN) task. Language lateralization results for these two tasks were compared to the verb-generation (VG) task. MEGI reconstruction parameters (regions and time windows) for NWR and PN were first defined in a presurgical training cohort by benchmarking these against laterality indices for VG. Optimized time windows and regions of interest (ROIs) for NWR and PN were determined by examining oscillations in the beta band (12-30 Hz) a marker of neural activity known to be concordant with the VG laterality index (LI). For NWR, additional ROIs include areas MTG/ITG and for both NWR and PN, the postcentral gyrus was included in analyses. Optimal time windows for NWR were defined as 650-850 ms (stimulus-locked) and -350 to -150 ms (response-locked) and for PN -450 to -250 ms (response-locked). To verify the optimal parameters defined in our training cohort for NWR and PN, we examined an independent validation cohort (n = 30 for NWR, n = 28 for PN) and found high concordance between VG laterality and PN laterality (82%) and between VG laterality and NWR laterality (87%). Finally, in a test cohort (n = 8) that underwent both the intracarotid amobarbital procedure (IAP) test and MEG for VG, NWR, and PN, we identified excellent concordance (100%) with IAP for VG + NWR + PN composite LI, high concordance for PN alone (87.5%), and moderate concordance for NWR alone (66.7%). These findings provide task options for non-invasive language mapping with MEGI that can be calibrated for language abilities of individual patients. Results also demonstrate that more accurate estimates can be obtained by combining laterality estimates obtained from multiple tasks. MEGI.
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Affiliation(s)
- Leighton B. N. Hinkley
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
| | - Elke De Witte
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Megan Cahill-Thompson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
| | - Danielle Mizuiri
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
| | - Coleman Garrett
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
| | - Susanne Honma
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
| | - Anne Findlay
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
| | - Maria Luisa Gorno-Tempini
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
- Memory and Aging Center, University of California, San Francisco, San Francisco, CA, United States
| | - Phiroz Tarapore
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Heidi E. Kirsch
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
| | - Peter Mariën
- Department of Neurology, Ziekenhuis Netwerk Antwerpen, Antwerp, Belguim
| | - John F. Houde
- Department of Otolaryngology; University of California, San Francisco, San Francisco, CA, United States
| | - Mitchel Berger
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Srikantan S. Nagarajan
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
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11
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Bowyer SM, Pang EW, Huang M, Papanicolaou AC, Lee RR. Presurgical Functional Mapping with Magnetoencephalography. Neuroimaging Clin N Am 2020; 30:159-174. [DOI: 10.1016/j.nic.2020.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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12
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Mapping critical hubs of receptive and expressive language using MEG: A comparison against fMRI. Neuroimage 2019; 201:116029. [PMID: 31325641 DOI: 10.1016/j.neuroimage.2019.116029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 07/08/2019] [Accepted: 07/16/2019] [Indexed: 01/22/2023] Open
Abstract
The complexity of the widespread language network makes it challenging for accurate localization and lateralization. Using large-scale connectivity and graph-theoretical analyses of task-based magnetoencephalography (MEG), we aimed to provide robust representations of receptive and expressive language processes, comparable with spatial profiles of corresponding functional magnetic resonance imaging (fMRI). We examined MEG and fMRI data from 12 healthy young adults (age 20-37 years) completing covert auditory word-recognition task (WRT) and covert auditory verb-generation task (VGT). For MEG language mapping, broadband (3-30 Hz) beamformer sources were estimated, voxel-level connectivity was quantified using phase locking value, and highly connected hubs were characterized using eigenvector centrality graph measure. fMRI data were analyzed using a classic general linear model approach. A laterality index (LI) was computed for 20 language-specific frontotemporal regions for both MEG and fMRI. MEG network analysis showed bilateral and symmetrically distributed hubs within the left and right superior temporal gyrus (STG) during WRT and predominant hubs in left inferior prefrontal gyrus (IFG) during VGT. MEG and fMRI localization maps showed high correlation values within frontotemporal regions during WRT and VGT (r = 0.63, 0.74, q < 0.05, respectively). Despite good concordance in localization, notable discordances were observed in lateralization between MEG and fMRI. During WRT, MEG favored a left-hemispheric dominance of left STG (LI = 0.25 ± 0.22) whereas fMRI supported a bilateral representation of STG (LI = 0.08 ± 0.2). Laterality of MEG and fMRI during VGT consistently showed a strong asymmetry in left IFG regions (MEG-LI = 0.45 ± 0.35 and fMRI-LI = 0.46 ± 0.13). Our results demonstrate the utility of a large-scale connectivity and graph theoretical analyses for robust identification of language-specific regions. MEG hubs are in great agreement with the literature in revealing with canonical and extra-canonical language sites, thus providing additional support for the underlying topological organization of receptive and expressive language cortices. Discordances in lateralization may emphasize the need for multimodal integration of MEG and fMRI to obtain an excellent predictive value in a heterogeneous healthy population and patients with neurosurgical conditions.
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Kreidenhuber R, De Tiège X, Rampp S. Presurgical Functional Cortical Mapping Using Electromagnetic Source Imaging. Front Neurol 2019; 10:628. [PMID: 31249552 PMCID: PMC6584755 DOI: 10.3389/fneur.2019.00628] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/28/2019] [Indexed: 02/03/2023] Open
Abstract
Preoperative localization of functionally eloquent cortex (functional cortical mapping) is common clinical practice in order to avoid or reduce postoperative morbidity. This review aims at providing a general overview of magnetoencephalography (MEG) and high-density electroencephalography (hdEEG) based methods and their clinical role as compared to common alternatives for functional cortical mapping of (1) verbal language function, (2) sensorimotor cortex, (3) memory, (4) visual, and (5) auditory cortex. We highlight strengths, weaknesses and limitations of these functional cortical mapping modalities based on findings in the recent literature. We also compare their performance relative to other non-invasive functional cortical mapping methods, such as functional Magnetic Resonance Imaging (fMRI), Transcranial Magnetic Stimulation (TMS), and to invasive methods like the intracarotid Amobarbital Test (WADA-Test) or intracranial investigations.
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Affiliation(s)
- Rudolf Kreidenhuber
- Department of Neurology, Christian-Doppler Medical Center, Paracelsus Medical University, Salzburg, Austria.,Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
| | - Xavier De Tiège
- Laboratoire de Cartographie Fonctionelle du Cerveau, ULB Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium.,Department of Functional Neuroimaging, Service of Nuclear Medicine, CUB Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Stefan Rampp
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany.,Department of Neurosurgery, University Hospital Halle, Halle, Germany
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Balter S, Lin G, Leyden KM, Paul BM, McDonald CR. Neuroimaging correlates of language network impairment and reorganization in temporal lobe epilepsy. BRAIN AND LANGUAGE 2019; 193:31-44. [PMID: 27393391 PMCID: PMC5215985 DOI: 10.1016/j.bandl.2016.06.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 02/27/2016] [Accepted: 06/15/2016] [Indexed: 06/02/2023]
Abstract
Advanced, noninvasive imaging has revolutionized our understanding of language networks in the brain and is reshaping our approach to the presurgical evaluation of patients with epilepsy. Functional magnetic resonance imaging (fMRI) has had the greatest impact, unveiling the complexity of language organization and reorganization in patients with epilepsy both pre- and postoperatively, while volumetric MRI and diffusion tensor imaging have led to a greater appreciation of structural and microstructural correlates of language dysfunction in different epilepsy syndromes. In this article, we review recent literature describing how unimodal and multimodal imaging has advanced our knowledge of language networks and their plasticity in epilepsy, with a focus on the most frequently studied epilepsy syndrome in adults, temporal lobe epilepsy (TLE). We also describe how new analytic techniques (i.e., graph theory) are leading to a refined characterization of abnormal brain connectivity, and how subject-specific imaging profiles combined with clinical data may enhance the prediction of both seizure and language outcomes following surgical interventions.
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Affiliation(s)
- S Balter
- Department of Neurology, University of California, San Francisco, CA, United States; UCSF Comprehensive Epilepsy Center, United States
| | - G Lin
- Palo Alto University, Palo Alto, CA, United States
| | - K M Leyden
- Multimodal Imaging Laboratory, University of California, San Diego, CA, United States
| | - B M Paul
- Department of Neurology, University of California, San Francisco, CA, United States; UCSF Comprehensive Epilepsy Center, United States
| | - C R McDonald
- Multimodal Imaging Laboratory, University of California, San Diego, CA, United States; Department of Psychiatry, University of California, San Diego, CA, United States.
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15
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MEG Assessment of Expressive Language in Children Evaluated for Epilepsy Surgery. Brain Topogr 2019; 32:492-503. [PMID: 30895423 PMCID: PMC6476853 DOI: 10.1007/s10548-019-00703-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/07/2019] [Indexed: 11/21/2022]
Abstract
Establishing language dominance is an important step in the presurgical evaluation of patients with refractory epilepsy. In the absence of a universally accepted gold-standard non-invasive method to determine language dominance in the preoperative assessment, a range of tools and methodologies have recently received attention. When applied to pediatric age, many of the proposed methods, such as functional magnetic resonance imaging (fMRI), may present some challenges due to the time-varying effects of epileptogenic lesions and of on-going seizures on maturational phenomena. Magnetoencephalography (MEG) has the advantage of being insensitive to the distortive effects of anatomical lesions on brain microvasculature and to differences in the metabolism or vascularization of the developing brain and also provides a less intimidating recording environment for younger children. In this study we investigated the reliability of lateralized synchronous cortical activation during a verb generation task in a group of 28 children (10 males and 18 females, mean age 12 years) with refractory epilepsy who were evaluated for epilepsy surgery. The verb generation task was associated with significant decreases in beta oscillatory power (13–30 Hz) in frontal and temporal lobes. The MEG data were compared with other available presurgical non-invasive data including cortical stimulation, neuropsychological and fMRI data on language lateralization where available. We found that the lateralization of MEG beta power reduction was concordant with language dominance determined by one or more different assessment methods (i.e. cortical stimulation mapping, neuropsychological, fMRI or post-operative data) in 89% of patients. Our data suggest that qualitative hemispheric differences in task-related changes of spectral power could offer a promising insight into the contribution of dominant and non-dominant hemispheres in language processing and may help to characterize the specialization and lateralization of language processes in children.
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Lv Y, Li L, Song Y, Han Y, Zhou C, Zhou D, Zhang F, Xue Q, Liu J, Zhao L, Zhang C, Han X. The Local Brain Abnormalities in Patients With Transient Ischemic Attack: A Resting-State fMRI Study. Front Neurosci 2019; 13:24. [PMID: 30804735 PMCID: PMC6371034 DOI: 10.3389/fnins.2019.00024] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/11/2019] [Indexed: 11/28/2022] Open
Abstract
Background: Transient ischemic attack (TIA) is an important risk factor for stroke. Despite the transient episodes of clinical symptoms, brain alterations are still observed in patients with TIA. However, the functional mechanism of transient ischemia is still unclear. Here, we employed resting-state functional magnetic resonance imaging (rs-fMRI) to explore the functional abnormalities in patients with TIA. Methods: 48 TIA patients and 41 age- and sex-matched healthy controls (HCs) were enrolled in the study. For each participant, we collected rs-fMRI data and clinical/physiological/biochemical data. Amplitude of low frequency fluctuation (ALFF), regional homogeneity (ReHo), and degree centrality (DC) were then calculated. Two sample t-tests were performed to compare the ALFF, ReHo, and DC maps between the two groups. Furthermore, a correlation analysis was performed to explore the relationship between local brain abnormalities and clinical/physiological/biochemical characteristics tests in TIA patients. Results: Compared with the HCs, the TIA patients exhibited decreased ALFF in the left middle temporal gyrus, decreased DC in the triangular part of right inferior frontal gyrus, and no significant statistical difference in ReHo. No correlation was found between local abnormalities and clinical/physiological/biochemical scores in the patients with TIA. Conclusion: Collectively, we found decreased ALFF and DC in patients with TIA which provide evidence for local brain dysfunctions and may help to understand the pathological mechanism for the disease.
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Affiliation(s)
- Yating Lv
- Institutes of Psychological Sciences, Hangzhou Normal University, Hangzhou, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou, China.,Department of Neurology, Anshan Changda Hospital, Anshan, China
| | - Lingyu Li
- Institutes of Psychological Sciences, Hangzhou Normal University, Hangzhou, China.,Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou, China.,Department of Neurology, Anshan Changda Hospital, Anshan, China
| | - Yulin Song
- Department of Neurology, Anshan Changda Hospital, Anshan, China
| | - Yu Han
- Department of Neurology, The First Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Chengshu Zhou
- Department of Neurology, Anshan Changda Hospital, Anshan, China
| | - Dan Zhou
- Department of Neurology, Anshan Changda Hospital, Anshan, China
| | - Fuding Zhang
- Department of Neurology, Anshan Changda Hospital, Anshan, China
| | - Qiming Xue
- Department of Image, Anshan Changda Hospital, Anshan, China
| | - Jinling Liu
- Department of Ultrasonics, Anshan Changda Hospital, Anshan, China
| | - Lijuan Zhao
- Department of Neurology, Anshan Changda Hospital, Anshan, China
| | - Cairong Zhang
- Department of Neurology, Anshan Changda Hospital, Anshan, China
| | - Xiujie Han
- Department of Neurology, Anshan Changda Hospital, Anshan, China
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Traut T, Sardesh N, Bulubas L, Findlay A, Honma SM, Mizuiri D, Berger MS, Hinkley LB, Nagarajan SS, Tarapore PE. MEG imaging of recurrent gliomas reveals functional plasticity of hemispheric language specialization. Hum Brain Mapp 2018; 40:1082-1092. [PMID: 30549134 DOI: 10.1002/hbm.24430] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 11/09/2022] Open
Abstract
In patients with gliomas, changes in hemispheric specialization for language determined by magnetoencephalography (MEG) were analyzed to elucidate the impact of treatment and tumor recurrence on language networks. Demonstration of reorganization of language networks in these patients has significant implications on the prevention of postoperative functional loss and recovery. Whole-brain activity during an auditory verb generation task was estimated from MEG recordings in a group of 73 patients with recurrent gliomas. Hemisphere of language dominance was estimated using the language laterality index (LI), a measure derived from the task. The initial scan was performed prior to resection; patients subsequently underwent surgery and adjuvant treatment. A second scan was performed upon recurrence prior to repeat resection. The relationship between the shift in LI between scans and demographics, anatomic location, pathology, and adjuvant treatment was analyzed. Laterality shifts were observed between scans; the median percent change was 29.1% across all patients. Laterality shift magnitude and relative direction were associated with the initial position of language dominance; patients with increased lateralization experienced greater shifts than those presenting more bilateral representation. A change in LI from left or right to bilateral (or vice versa) occurred in 23.3% of patients; complete switch occurred in 5.5% of patients. Patients with tumors within the language-dominant hemisphere experienced significantly greater shifts than those with contralateral tumors. The majority of patients with glioma experience shifts in language network organization over time which correlate with the relative position of language lateralization and tumor location.
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Affiliation(s)
- Tavish Traut
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), San Francisco, California
| | - Nina Sardesh
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), San Francisco, California
| | - Lucia Bulubas
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), San Francisco, California.,Department of Neurosurgery, Klinikum Rechts der Isar, TU München, Munich, Germany.,TUM-Neuroimaging Center, Klinikum Rechts der Isar, TU München, Munich, Germany
| | - Anne Findlay
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), San Francisco, California
| | - Susanne M Honma
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), San Francisco, California
| | - Danielle Mizuiri
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), San Francisco, California
| | - Mitchel S Berger
- Department of Neurological Surgery, University of California, San Francisco (UCSF), San Francisco, California
| | - Leighton B Hinkley
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), San Francisco, California
| | - Srikantan S Nagarajan
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), San Francisco, California
| | - Phiroz E Tarapore
- Biomagnetic Imaging Lab, Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), San Francisco, California.,Department of Neurological Surgery, University of California, San Francisco (UCSF), San Francisco, California
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Magnetoencephalographic Mapping of Epileptic Spike Population Using Distributed Source Analysis: Comparison With Intracranial Electroencephalographic Spikes. J Clin Neurophysiol 2018; 35:339-345. [PMID: 29746391 DOI: 10.1097/wnp.0000000000000476] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
INTRODUCTION This study evaluates magnetoencephalographic (MEG) spike population as compared with intracranial electroencephalographic (IEEG) spikes using a quantitative method based on distributed source analysis. METHODS We retrospectively studied eight patients with medically intractable epilepsy who had an MEG and subsequent IEEG monitoring. Fifty MEG spikes were analyzed in each patient using minimum norm estimate. For individual spikes, each vertex in the source space was considered activated when its source amplitude at the peak latency was higher than a threshold, which was set at 50% of the maximum amplitude over all vertices. We mapped the total count of activation at each vertex. We also analyzed 50 IEEG spikes in the same manner over the intracranial electrodes and created the activation count map. The location of the electrodes was obtained in the MEG source space by coregistering postimplantation computed tomography to MRI. We estimated the MEG- and IEEG-active regions associated with the spike populations using the vertices/electrodes with a count over 25. RESULTS The activation count maps of MEG spikes demonstrated the localization associated with the spike population by variable count values at each vertex. The MEG-active region overlapped with 65 to 85% of the IEEG-active region in our patient group. CONCLUSIONS Mapping the MEG spike population is valid for demonstrating the trend of spikes clustering in patients with epilepsy. In addition, comparison of MEG and IEEG spikes quantitatively may be informative for understanding their relationship.
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Hari R, Baillet S, Barnes G, Burgess R, Forss N, Gross J, Hämäläinen M, Jensen O, Kakigi R, Mauguière F, Nakasato N, Puce A, Romani GL, Schnitzler A, Taulu S. IFCN-endorsed practical guidelines for clinical magnetoencephalography (MEG). Clin Neurophysiol 2018; 129:1720-1747. [PMID: 29724661 PMCID: PMC6045462 DOI: 10.1016/j.clinph.2018.03.042] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 03/18/2018] [Accepted: 03/24/2018] [Indexed: 12/22/2022]
Abstract
Magnetoencephalography (MEG) records weak magnetic fields outside the human head and thereby provides millisecond-accurate information about neuronal currents supporting human brain function. MEG and electroencephalography (EEG) are closely related complementary methods and should be interpreted together whenever possible. This manuscript covers the basic physical and physiological principles of MEG and discusses the main aspects of state-of-the-art MEG data analysis. We provide guidelines for best practices of patient preparation, stimulus presentation, MEG data collection and analysis, as well as for MEG interpretation in routine clinical examinations. In 2017, about 200 whole-scalp MEG devices were in operation worldwide, many of them located in clinical environments. Yet, the established clinical indications for MEG examinations remain few, mainly restricted to the diagnostics of epilepsy and to preoperative functional evaluation of neurosurgical patients. We are confident that the extensive ongoing basic MEG research indicates potential for the evaluation of neurological and psychiatric syndromes, developmental disorders, and the integrity of cortical brain networks after stroke. Basic and clinical research is, thus, paving way for new clinical applications to be identified by an increasing number of practitioners of MEG.
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Affiliation(s)
- Riitta Hari
- Department of Art, Aalto University, Helsinki, Finland.
| | - Sylvain Baillet
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Gareth Barnes
- Wellcome Centre for Human Neuroimaging, University College of London, London, UK
| | - Richard Burgess
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Nina Forss
- Clinical Neuroscience, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Joachim Gross
- Centre for Cognitive Neuroimaging, University of Glasgow, Glasgow, UK; Institute for Biomagnetism and Biosignalanalysis, University of Muenster, Germany
| | - Matti Hämäläinen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; NatMEG, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ole Jensen
- Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Ryusuke Kakigi
- Department of Integrative Physiology, National Institute of Physiological Sciences, Okazaki, Japan
| | - François Mauguière
- Department of Functional Neurology and Epileptology, Neurological Hospital & University of Lyon, Lyon, France
| | | | - Aina Puce
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Gian-Luca Romani
- Department of Neuroscience, Imaging and Clinical Sciences, Università degli Studi G. D'Annunzio, Chieti, Italy
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, and Department of Neurology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Samu Taulu
- Institute for Learning & Brain Sciences, University of Washington, Seattle, WA, USA; Department of Physics, University of Washington, Seattle, WA, USA
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Wilenius J, Lehtinen H, Paetau R, Salmelin R, Kirveskari E. A simple magnetoencephalographic auditory paradigm may aid in confirming left-hemispheric language dominance in epilepsy patients. PLoS One 2018; 13:e0200073. [PMID: 29966017 PMCID: PMC6028140 DOI: 10.1371/journal.pone.0200073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 06/19/2018] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE The intracarotid amobarbital procedure (IAP) is the current "gold standard" in the preoperative assessment of language lateralization in epilepsy surgery candidates. It is, however, invasive and has several limitations. Here we tested a simple noninvasive language lateralization test performed with magnetoencephalography (MEG). METHODS We recorded auditory MEG responses to pairs of vowels and pure tones in 16 epilepsy surgery candidates who had undergone IAP. For each individual, we selected the pair of planar gradiometer sensors with the strongest N100m response to vowels in each hemisphere and-from the vector sum of signals of this gradiometer pair-calculated the vowel/tone amplitude ratio in the left (L) and right (R) hemisphere and, subsequently, the laterality index: LI = (L-R)/(L+R). In addition to the analysis using a single sensor pair, an alternative analysis was performed using averaged responses over 18 temporal sensor pairs in both hemispheres. RESULTS The laterality index did not correlate significantly with the lateralization data obtained from the IAP. However, an MEG pattern of stronger responses to vowels than tones in the left hemisphere and stronger responses to tones than vowels in the right hemisphere was associated with left-hemispheric language dominance in the IAP in all the six patients who showed this pattern. This results in a specificity of 100% and a sensitivity of 67% of this MEG pattern in predicting left-hemispheric language dominance (p = 0.01, Fisher's exact test). In the analysis using averaged responses over temporal channels, one additional patient who was left-dominant in IAP showed this particular MEG pattern, increasing the sensitivity to 78% (p = 0.003). SIGNIFICANCE This simple MEG paradigm shows promise in feasibly and noninvasively confirming left-hemispheric language dominance in epilepsy surgery candidates. It may aid in reducing the need for the IAP, if the results are confirmed in larger patient samples.
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Affiliation(s)
- Juha Wilenius
- Clinical Neurosciences, Department of Clinical Neurophysiology, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Henri Lehtinen
- Epilepsy Unit, Department of Pediatric Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ritva Paetau
- Clinical Neurosciences, Department of Clinical Neurophysiology, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Epilepsy Unit, Department of Pediatric Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Riitta Salmelin
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | - Erika Kirveskari
- Clinical Neurosciences, Department of Clinical Neurophysiology, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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On the relative merits of invasive and non-invasive pre-surgical brain mapping: New tools in ablative epilepsy surgery. Epilepsy Res 2018; 142:153-155. [DOI: 10.1016/j.eplepsyres.2017.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/01/2017] [Accepted: 07/01/2017] [Indexed: 11/23/2022]
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Kemp S, Prendergast G, Karapanagiotidis T, Baker G, Kelly TP, Patankar T, Keller SS. Concordance between the Wada test and neuroimaging lateralization: Influence of imaging modality (fMRI and MEG) and patient experience. Epilepsy Behav 2018; 78:155-160. [PMID: 29245083 DOI: 10.1016/j.yebeh.2017.09.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/26/2017] [Accepted: 09/28/2017] [Indexed: 11/24/2022]
Abstract
The Wada test remains the traditional test for lateralizing language and memory function prior to epilepsy surgery. Functional imaging, particularly functional MRI (fMRI), has made progress in the language domain, but less so in the memory domain. Magnetoencephalography (MEG) has received less research attention, but shows promise, particularly for language lateralization. We recruited a consecutive sample of 19 patients with epilepsy who had completed presurgical work-up, including the Wada test, and compared fMRI (memory) and MEG (language and memory) with Wada test results. The main research question was the concordance between Wada and these two imaging techniques as preepilepsy surgery investigations. We were also interested in the acceptability of the three techniques to patients. Concordance rates (N=16) were nonsignificant (Cohen's Kappa) between fMRI and Wada test (memory) and between MEG and Wada test (memory and language). The Wada test was a well-established protocol used at several epilepsy surgery centers in the UK. Patients generally found the Wada test an odd, but not aversive procedure. Sixteen (84%) patients who were scanned reported some level of obtundation in MEG. We present these discordant findings in support of the position that functional imaging and the Wada test are distinctive procedures, with little in the way of overlapping mechanisms, and that patient's experience should be taken into account when procedures are selected and offered to them.
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Affiliation(s)
- Steven Kemp
- Department of Clinical and Health Psychology, St James's University Hospital, Leeds, UK.
| | | | | | - Gus Baker
- University of Liverpool, UK/The Walton Centre NHS Foundation Trust, Liverpool, UK
| | | | | | - Simon S Keller
- University of Liverpool, UK/The Walton Centre NHS Foundation Trust, Liverpool, UK; Department of Neuroradiology, The Walton Centre NHS Foundation Trust, Liverpool, UK
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Raghavan M, Li Z, Carlson C, Anderson CT, Stout J, Sabsevitz DS, Swanson SJ, Binder JR. MEG language lateralization in partial epilepsy using dSPM of auditory event-related fields. Epilepsy Behav 2017; 73:247-255. [PMID: 28662463 DOI: 10.1016/j.yebeh.2017.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/19/2017] [Accepted: 06/05/2017] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Methods employed to determine hemispheric language dominance using magnetoencephalography (MEG) have differed significantly across studies in the choice of language-task, the nature of the physiological response studied, recording hardware, and source modeling methods. Our goal was to determine whether an analysis based on distributed source modeling can replicate the results of prior studies that have used dipole-modeling of event-related fields (ERFs) generated by an auditory word-recognition task to determine language dominance in patients with epilepsy. METHODS We analyzed data from 45 adult patients with drug-resistant partial epilepsy who performed an auditory word-recognition task during MEG recording and also completed a language fMRI study as part of their evaluation for epilepsy surgery. Source imaging of auditory ERFs was performed using dynamic statistical parametric mapping (dSPM). Language laterality indices (LIs) were calculated for four regions of interest (ROIs) by counting above-threshold activations within a 300-600ms time window after stimulus onset. Language laterality (LL) classifications based on these LIs were compared to the results from fMRI. RESULTS The most lateralized MEG responses to language stimuli were observed in a parietal region that included the angular and supramarginal gyri (AngSmg). In this region, using a half-maximal threshold, source activations were left dominant in 32 (71%) patients, right dominant in 8 (18%), and symmetric in 5 patients (11%). The best agreement between MEG and fMRI on the ternary classification of regional language dominance into left, right, or symmetric groups was also found at the AngSmg ROI (69%). This was followed by the whole-hemisphere and temporal ROIs (both 62%). The frontal ROI showed the least agreement with fMRI (51%). Gross discordances between MEG and FMRI findings were disproportionately of the type where MEG favored atypical right-hemispheric language in a patient with right-hemispheric seizure origin (p<0.05 at three of the four ROIs). SIGNIFICANCE In a parietal region that includes the angular and supramarginal gyri, language laterality estimates based on dSPM of ERFs during auditory word-recognition shows a degree of MEG-fMRI concordance that is comparable to previously published estimates for MEG-Wada concordance using dipole counting methods and the same task. Our data also suggest that MEG language laterality estimates based on this task may be influenced by the laterality of epileptic networks in some patients. This has not been reported previously and deserves further study.
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Affiliation(s)
- Manoj Raghavan
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Zhimin Li
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Chad Carlson
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Jeffrey Stout
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - David S Sabsevitz
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Sara J Swanson
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jeffrey R Binder
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
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Presurgical Mapping of the Language Network Using Resting-state Functional Connectivity. Top Magn Reson Imaging 2016; 25:19-24. [PMID: 26848557 DOI: 10.1097/rmr.0000000000000073] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Resting-state functional magnetic resonance imaging (resting-state fMRI) is a tool for investigating the functional networks that arise during the resting state of the brain. Recent advances of the resting-state fMRI analysis suggest its feasibility for evaluating language function. The most common clinical application is for presurgical mapping of cortex for a brain tumor or for resective epilespy surgery. In this article, we review the techniques and presurgical applications of resting-state fMRI analysis for language evaluation, and discuss the use in the clinical setting, focusing on planning for neurosurgery.
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Fully automated quality assurance and localization of volumetric MEG for single-subject mapping. J Neurosci Methods 2016; 266:21-31. [PMID: 26993819 DOI: 10.1016/j.jneumeth.2016.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 11/20/2022]
Abstract
BACKGROUND Robust and reproducible source mapping with magnetoencephalography is particularly challenging at the individual level. We evaluated a receiver-operating characteristic reliability (ROC-r) method for automated production of volumetric MEG maps in single-subjects. ROC-r provides quality assurance comparable to that offered by goodness-of-fit (GoF) and confidence volume (CV) for equivalent current dipole (ECD) modeling. NEW METHOD ROC-r utilizes within-session reproducibility for quality assurance, latency identification, and thresholding of volumetric source maps. We tested ROC-r on simulated and real MEG with a strongly focal source, using somatosensory evoked fields (SEFs) elicited by bilateral median nerve stimulation (MNS). For quality assurance, the ROC-r reliable fraction (FR) was compared to the ECD GoF and CV. Peak beamformer locations and latencies identified by ROC-r were compared to the ECD for co-localization accuracy. RESULTS The predominant component of the SEF response occurred around 35ms, contralateral to the MNS. COMPARISON WITH EXISTING METHODS FR and 1/CV were more strongly correlated (mean Pearson's correlation: 0.76; 95% CI 0.60-0.87) than FR and GoF (0.65; 95% CI 0.32-0.85). There was no difference in the latency of the peak GoF (35.0+/-0.6ms), CV (34.8+/-0.7ms) and FR (35.5+/-0.8ms). The ECD fits and ROC-r peaks co-localized to within a mean (median) distance of 8.3+/-5.9mm (6.2mm). CONCLUSION ROC-r volumetric mapping co-localized closely with the standard ECD approach. This analysis can be added to any whole-brain MEG source imaging protocol, and is especially useful for single-subject mapping. Additionally, the development of FR as an analogue to GoF or CV for volumetric mapping is a critical improvement for clinical applications.
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Pirmoradi M, Jemel B, Gallagher A, Tremblay J, D’Hondt F, Nguyen DK, Béland R, Lassonde M. Verbal memory and verbal fluency tasks used for language localization and lateralization during magnetoencephalography. Epilepsy Res 2016; 119:1-9. [DOI: 10.1016/j.eplepsyres.2015.11.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/02/2015] [Accepted: 11/13/2015] [Indexed: 11/27/2022]
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Larvie M, Fischl B. Volumetric and fiber-tracing MRI methods for gray and white matter. HANDBOOK OF CLINICAL NEUROLOGY 2016; 135:39-60. [PMID: 27432659 DOI: 10.1016/b978-0-444-53485-9.00003-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Magnetic resonance imaging (MRI) is capable of generating high-resolution brain images with fine anatomic detail and unique tissue contrasts that reveal structures that are not visible to the eye. Sharply defined gray- and white-matter interfaces allow for quantitative anatomic analysis that can be accurately performed with largely automated segmentation methods. In an analogous fashion, diffusion MRI in the brain provides structural information based on contrasts derived from the diffusivity of water in brain tissue, which can highlight the orientation of neuronal axons. Also using largely automated methods, diffusion MRI can be used to generate models of white-matter tracts throughout the brain, a method known as tractography, as well as characterize the microstructural integrity of neuronal axons. Tractographic analysis has helped to define connectivity in the brain that powerfully informs understanding of brain function, and, together with other diffusion metrics, is useful in evaluation of the normal and diseased brain. The quantitative methods of brain segmentation, tractography, and diffusion MRI extend MRI into a realm beyond visual inspection and provide otherwise unachievable sensitivity and specificity in the analysis of brain structure and function.
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Affiliation(s)
- Mykol Larvie
- Divisions of Neuroradiology and Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA, USA.
| | - Bruce Fischl
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
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Rezaie R, Narayana S, Schiller K, Birg L, Wheless JW, Boop FA, Papanicolaou AC. Assessment of hemispheric dominance for receptive language in pediatric patients under sedation using magnetoencephalography. Front Hum Neurosci 2014; 8:657. [PMID: 25191260 PMCID: PMC4140211 DOI: 10.3389/fnhum.2014.00657] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 08/06/2014] [Indexed: 12/11/2022] Open
Abstract
Non-invasive assessment of hemispheric dominance for receptive language using magnetoencephalography (MEG) is now a well-established procedure used across several epilepsy centers in the context of pre-surgical evaluation of children and adults while awake, alert and attentive. However, the utility of MEG for the same purpose, in cases of sedated patients, is contested. Establishment of the efficiency of MEG is especially important in the case of children who, for a number of reasons, must be assessed under sedation. Here we explored the efficacy of MEG language mapping under sedation through retrospective review of 95 consecutive pediatric patients, who underwent our receptive language test as part of routine clinical evaluation. Localization of receptive language cortex and subsequent determination of laterality was successfully completed in 78% (n = 36) and 55% (n = 27) of non-sedated and sedated patients, respectively. Moreover, the proportion of patients deemed left hemisphere dominant for receptive language did not differ between non-sedated and sedated patients, exceeding 90% in both groups. Considering the challenges associated with assessing brain function in pediatric patients, the success of passive MEG in the context of the cases reviewed in this study support the utility of this method in pre-surgical receptive language mapping.
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Affiliation(s)
- Roozbeh Rezaie
- Department of Pediatrics, Division of Clinical Neurosciences, University of Tennessee Health Science Center Memphis, TN, USA ; Neuroscience Institute, Le Bonheur Children's Hospital Memphis, TN, USA
| | - Shalini Narayana
- Department of Pediatrics, Division of Clinical Neurosciences, University of Tennessee Health Science Center Memphis, TN, USA ; Neuroscience Institute, Le Bonheur Children's Hospital Memphis, TN, USA
| | | | - Liliya Birg
- Neuroscience Institute, Le Bonheur Children's Hospital Memphis, TN, USA
| | - James W Wheless
- Neuroscience Institute, Le Bonheur Children's Hospital Memphis, TN, USA ; Division of Pediatric Neurology, Department of Pediatrics, University of Tennessee Health Science Center Memphis, TN, USA
| | - Frederick A Boop
- Neuroscience Institute, Le Bonheur Children's Hospital Memphis, TN, USA ; Department of Neurosurgery, University of Tennessee Health Science Center Memphis, TN, USA
| | - Andrew C Papanicolaou
- Department of Pediatrics, Division of Clinical Neurosciences, University of Tennessee Health Science Center Memphis, TN, USA ; Neuroscience Institute, Le Bonheur Children's Hospital Memphis, TN, USA
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Sowman PF, Crain S, Harrison E, Johnson BW. Lateralization of brain activation in fluent and non-fluent preschool children: a magnetoencephalographic study of picture-naming. Front Hum Neurosci 2014; 8:354. [PMID: 24904388 PMCID: PMC4035571 DOI: 10.3389/fnhum.2014.00354] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 05/09/2014] [Indexed: 11/30/2022] Open
Abstract
The neural causes of stuttering remain unknown. One explanation comes from neuroimaging studies that have reported abnormal lateralization of activation in the brains of people who stutter. However, these findings are generally based on data from adults with a long history of stuttering, raising the possibility that the observed lateralization anomalies are compensatory rather than causal. The current study investigated lateralization of brain activity in language-related regions of interest in young children soon after the onset of stuttering. We tested 24 preschool-aged children, half of whom had a positive diagnosis of stuttering. All children participated in a picture-naming experiment whilst their brain activity was recorded by magnetoencephalography. Source analysis performed during an epoch prior to speech onset was used to assess lateralized activation in three regions of interest. Activation was significantly lateralized to the left hemisphere in both groups and not different between groups. This study shows for the first time that significant speech preparatory brain activation can be identified in young children during picture-naming and supports the contention that, in stutterers, aberrant lateralization of brain function may be the result of neuroplastic adaptation that occurs as the condition becomes chronic.
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Affiliation(s)
- Paul F. Sowman
- Department of Cognitive Science, ARC Centre of Excellence for Cognition and its Disorders, Macquarie University, Sydney, NSW, Australia
- Perception and Action Research Centre (PARC), Faculty of Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Stephen Crain
- Department of Linguistics, ARC Centre of Excellence for Cognition and its Disorders, Macquarie University, Sydney, NSW, Australia
| | - Elisabeth Harrison
- Department of Linguistics, ARC Centre of Excellence for Cognition and its Disorders, Macquarie University, Sydney, NSW, Australia
| | - Blake W. Johnson
- Department of Cognitive Science, ARC Centre of Excellence for Cognition and its Disorders, Macquarie University, Sydney, NSW, Australia
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Papanicolaou AC, Rezaie R, Narayana S, Choudhri AF, Wheless JW, Castillo EM, Baumgartner JE, Boop FA. Is it time to replace the Wada test and put awake craniotomy to sleep? Epilepsia 2014; 55:629-632. [DOI: 10.1111/epi.12569] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Andrew C. Papanicolaou
- Department of Pediatrics; Division of Clinical Neurosciences; University of Tennessee Health Science Center; Memphis Tennessee U.S.A
- Neuroscience Institute; Le Bonheur Children's Hospital; Memphis Tennessee U.S.A
| | - Roozbeh Rezaie
- Department of Pediatrics; Division of Clinical Neurosciences; University of Tennessee Health Science Center; Memphis Tennessee U.S.A
- Neuroscience Institute; Le Bonheur Children's Hospital; Memphis Tennessee U.S.A
| | - Shalini Narayana
- Department of Pediatrics; Division of Clinical Neurosciences; University of Tennessee Health Science Center; Memphis Tennessee U.S.A
- Neuroscience Institute; Le Bonheur Children's Hospital; Memphis Tennessee U.S.A
| | - Asim F. Choudhri
- Neuroscience Institute; Le Bonheur Children's Hospital; Memphis Tennessee U.S.A
- Department of Radiology; University of Tennessee Health Science Center; Memphis Tennessee U.S.A
- Department of Neurosurgery; University of Tennessee Health Science Center; Memphis Tennessee U.S.A
| | - James W. Wheless
- Neuroscience Institute; Le Bonheur Children's Hospital; Memphis Tennessee U.S.A
- Department of Pediatrics; Division of Pediatric Neurology; University of Tennessee Health Science Center; Memphis Tennessee U.S.A
| | - Eduardo M. Castillo
- Magnetoencephalography Laboratory; Florida Hospital for Children; Orlando Florida U.S.A
| | - James E. Baumgartner
- Comprehensive Epilepsy Center at Florida Hospital for Children; Orlando Florida U.S.A
| | - Frederick A. Boop
- Department of Neurosurgery; University of Tennessee Health Science Center; Memphis Tennessee U.S.A
- Department of Pediatrics; Division of Pediatric Neurology; University of Tennessee Health Science Center; Memphis Tennessee U.S.A
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Tanaka N, Peters JM, Prohl AK, Takaya S, Madsen JR, Bourgeois BF, Dworetzky BA, Hämäläinen MS, Stufflebeam SM. Clinical value of magnetoencephalographic spike propagation represented by spatiotemporal source analysis: correlation with surgical outcome. Epilepsy Res 2013; 108:280-8. [PMID: 24315019 DOI: 10.1016/j.eplepsyres.2013.11.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 10/05/2013] [Accepted: 11/03/2013] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To investigate the correlation between spike propagation represented by spatiotemporal source analysis of magnetoencephalographic (MEG) spikes and surgical outcome in patients with temporal lobe epilepsy. METHODS Thirty-seven patients were divided into mesial (n=27) and non-mesial (n=10) groups based on the presurgical evaluation. In each patient, ten ipsilateral spikes were averaged, and spatiotemporal source maps of the averaged spike were obtained by using minimum norm estimate. Regions of interest (ROIs) were created including temporoparietal, inferior frontal, mesial temporal, anterior and posterior part of the lateral temporal cortex. We extracted activation values from the source maps and the threshold was set at half of the maximum activation at the peak latency. The leading and propagated areas of the spike were defined as those ROIs with activation reaching the threshold at the earliest and at the peak latencies, respectively. Surgical outcome was assessed based on Engel's classification. Binary variables were created from leading areas (restricted to the anterior and mesial temporal ROIs or not) and from propagation areas (involving the temporoparietal ROI or not), and for surgical outcome (Class I or not). Fisher's exact test was used for significance testing. RESULTS In total and mesial group, restricted anterior/mesial temporal leading areas were correlated with Class I (p<0.05). Temporoparietal propagation was correlated with Class II-IV (p<0.05). For the non-mesial group, no significant relation was found. CONCLUSIONS Spike propagation patterns represented by spatiotemporal source analysis of MEG spikes may provide useful information for prognostic implication in presurgical evaluation of epilepsy.
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Affiliation(s)
- Naoaki Tanaka
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129, USA.
| | - Jurriaan M Peters
- Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Anna K Prohl
- Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Shigetoshi Takaya
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129, USA
| | - Joseph R Madsen
- Department of Neurosurgery, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Blaise F Bourgeois
- Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Barbara A Dworetzky
- Department of Neurology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
| | - Matti S Hämäläinen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129, USA
| | - Steven M Stufflebeam
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129, USA
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