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Ocklenburg S, Mundorf A, Gerrits R, Karlsson EM, Papadatou-Pastou M, Vingerhoets G. Clinical implications of brain asymmetries. Nat Rev Neurol 2024; 20:383-394. [PMID: 38783057 DOI: 10.1038/s41582-024-00974-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2024] [Indexed: 05/25/2024]
Abstract
No two human brains are alike, and with the rise of precision medicine in neurology, we are seeing an increased emphasis on understanding the individual variability in brain structure and function that renders every brain unique. Functional and structural brain asymmetries are a fundamental principle of brain organization, and recent research suggests substantial individual variability in these asymmetries that needs to be considered in clinical practice. In this Review, we provide an overview of brain asymmetries, variations in such asymmetries and their relevance in the clinical context. We review recent findings on brain asymmetries in neuropsychiatric and neurodevelopmental disorders, as well as in specific learning disabilities, with an emphasis on large-scale database studies and meta-analyses. We also highlight the relevance of asymmetries for disease symptom onset in neurodegenerative diseases and their implications for lateralized treatments, including brain stimulation. We conclude that alterations in brain asymmetry are not sufficiently specific to act as diagnostic biomarkers but can serve as meaningful symptom or treatment response biomarkers in certain contexts. On the basis of these insights, we provide several recommendations for neurological clinical practice.
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Affiliation(s)
- Sebastian Ocklenburg
- Department of Psychology, MSH Medical School Hamburg, Hamburg, Germany.
- ICAN Institute for Cognitive and Affective Neuroscience, MSH Medical School Hamburg, Hamburg, Germany.
- Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Bochum, Germany.
| | - Annakarina Mundorf
- ISM Institute for Systems Medicine and Department of Human Medicine, MSH Medical School Hamburg, Hamburg, Germany
- Division of Cognitive Neuroscience, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Robin Gerrits
- Department of Experimental-Clinical and Health Psychology, Ghent University, Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging (GIfMI), Ghent University, Ghent, Belgium
| | - Emma M Karlsson
- Department of Experimental-Clinical and Health Psychology, Ghent University, Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging (GIfMI), Ghent University, Ghent, Belgium
| | - Marietta Papadatou-Pastou
- National and Kapodistrian University of Athens, Athens, Greece
- Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Guy Vingerhoets
- Department of Experimental-Clinical and Health Psychology, Ghent University, Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging (GIfMI), Ghent University, Ghent, Belgium
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Fava A, Lisi SV, Mauro L, Morace R, Ciavarro M, Gorgoglione N, Petrella G, Quarato PP, Di Gennaro G, di Russo P, Esposito V. The anterior sylvian point as a reliable landmark for the anterior temporal lobectomy in mesial temporal lobe epilepsy: technical note, case series, and cadaveric dissection. Front Med (Lausanne) 2024; 11:1352321. [PMID: 39015783 PMCID: PMC11250084 DOI: 10.3389/fmed.2024.1352321] [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: 12/07/2023] [Accepted: 05/29/2024] [Indexed: 07/18/2024] Open
Abstract
Introduction Mesial temporal lobe epilepsy (MTLE) is one of the most prevalent forms of focal epilepsy in surgical series, particularly among adults. Over the decades, different surgical strategies have been developed to address drug-resistant epilepsy while safeguarding neurological and cognitive functions. Among these strategies, anterior temporal lobectomy (ATL), involving the removal of the temporal pole and mesial temporal structures, has emerged as a widely employed technique. Numerous modifications have been proposed to mitigate the risks associated with aphasia, cognitive issues, and visual field defects. Methods Our approach is elucidated through intraoperative and cadaveric dissections, complemented by neuroradiological and cadaveric measurements of key anatomical landmarks. A retrospective analysis of patients with drug-resistant MTLE who were treated using our ATL technique at IRCCS Neuromed (Pozzilli) is presented. Results A total of 385 patients were treated with our ATL subpial technique anatomically focused on the anterior Sylvian point (ASyP). The mean FU was 9.9 ± 5.4 years (range 1-24). In total, 84%of patients were free of seizures during the last follow-up, with no permanent neurological deficits. Transient defects were as follows: aphasia in 3% of patients, visual field defects in 2% of patients, hemiparesis in 2% of patients, and cognitive/memory impairments in 0.8% of patients. In cadaveric dissections, the ASyP was found at a mean distance from the temporal pole of 3.4 ± 0.2 cm (range 3-3.8) at the right side and 3.5 ± 0.2 cm (3.2-3.9) at the left side. In neuroimaging, the ASyP resulted anterior to the temporal horn tip in all cases at a mean distance of 3.2 ± 0.3 mm (range 2.7-3.6) at the right side and 3.5 ± 0.4 mm (range 2.8-3.8) at the left side. Discussion To the best of our knowledge, this study first introduces the ASyP as a reliable and reproducible cortical landmark to perform the ATL to overcome the patients' variabilities, the risk of Meyer's loop injury, and the bias of intraoperative measurements. Our findings demonstrate that ASyP can be a safe cortical landmark that is useful in MTLE surgery because it is constantly present and is anterior to risky temporal regions such as temporal horn and language networks.
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Affiliation(s)
- Arianna Fava
- IRCCS Neuromed, Pozzilli, Italy
- Laboratory of Neuroanatomy “G. Cantore”, IRCCS Neuromed, Pozzilli, Italy
- Department of Human Neurosciences, University of Rome “La Sapienza”, Rome, Italy
| | | | - Luigi Mauro
- Laboratory of Neuroanatomy “G. Cantore”, IRCCS Neuromed, Pozzilli, Italy
| | | | | | - Nicola Gorgoglione
- IRCCS Neuromed, Pozzilli, Italy
- Laboratory of Neuroanatomy “G. Cantore”, IRCCS Neuromed, Pozzilli, Italy
| | | | | | | | - Paolo di Russo
- IRCCS Neuromed, Pozzilli, Italy
- Laboratory of Neuroanatomy “G. Cantore”, IRCCS Neuromed, Pozzilli, Italy
| | - Vincenzo Esposito
- IRCCS Neuromed, Pozzilli, Italy
- Laboratory of Neuroanatomy “G. Cantore”, IRCCS Neuromed, Pozzilli, Italy
- Department of Human Neurosciences, University of Rome “La Sapienza”, Rome, Italy
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Sabadell V, Trébuchon A, Alario FX. An exploration of anomia rehabilitation in drug-resistant temporal lobe epilepsy. Epilepsy Behav Rep 2024; 27:100681. [PMID: 38881885 PMCID: PMC11178986 DOI: 10.1016/j.ebr.2024.100681] [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: 02/28/2024] [Revised: 05/15/2024] [Accepted: 05/27/2024] [Indexed: 06/18/2024] Open
Abstract
Around 40% of patients who undergo a left temporal lobe epilepsy (LTLE) surgery suffer from anomia (word-finding difficulties), a condition that negatively impacts quality of life. Despite these observations, language rehabilitation is still understudied in LTLE. We assessed the effect of a four-week rehabilitation on four drug-resistant LTLE patients after their surgery. The anomia rehabilitation was based on cognitive descriptions of word finding deficits in LTLE. Its primary ingredients were psycholinguistic tasks and a psychoeducation approach to help patients cope with daily communication issues. We repeatedly assessed naming skills for trained and untrained words, before and during the therapy using an A-B design with follow-up and replication. Subjective anomia complaint and standardized language assessments were also collected. We demonstrated the effectiveness of the rehabilitation program for trained words despite the persistence of seizures. Furthermore, encouraging results were observed for untrained items. Variable changes in anomia complaint were observed. One patient who conducted the protocol as self-rehabilitation responded similarly to the others, despite the different manner of intervention. These results open promising avenues for helping epileptic patients suffering from anomia. For example, this post-operative program could easily be adapted to be conducted preoperatively.
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Affiliation(s)
| | - Agnès Trébuchon
- Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
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Volfart A, Rossion B, Brissart H, Busigny T, Colnat-Coulbois S, Maillard L, Jonas J. Stability of face recognition abilities after left or right anterior temporal lobectomy. J Neuropsychol 2024; 18 Suppl 1:115-133. [PMID: 37391874 DOI: 10.1111/jnp.12337] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/08/2023] [Accepted: 06/20/2023] [Indexed: 07/02/2023]
Abstract
Patients with anterior temporal lobe (ATL) resection due to mesial temporal lobe epilepsy (MTLE) have difficulties at identifying familiar faces and explicitly remembering newly learned faces but their ability to individuate unfamiliar faces remains largely unknown. Moreover, the extent to which their difficulties with familiar face identity recognition and learning is truly due to the ATL resection remains unknown. Here, we report a study of 24 MTLE patients and matched healthy controls tested with an extensive set of seven face and visual object recognition tasks (including three tasks evaluating unfamiliar face individuation) before and about 6 months after unilateral (nine left, 15 right) ATL resection. We found that ATL resection has little or no effect on the patients' preserved pre-surgical ability to perform unfamiliar face individuation, both at the group and individual levels. More surprisingly, ATL resection also has little effect on the patients' performance at recognizing and naming famous faces as well as at learning new faces. A substantial proportion of right MTLE patients (33%) even improved their response times on several tasks, which may indicate a functional release of visuo-spatial processing after resection in the right ATL. Altogether this study shows that face recognition abilities are mainly unaffected by ATL resection in MTLE, either because the critical regions for face recognition are spared or because performance at some tasks is already lower than normal preoperatively. Overall, these findings urge caution when interpreting the causal effect of brain lesions on face recognition ability in patients with ATL resection due to MTLE. They also illustrate the complexity of predicting cognitive outcomes after epilepsy surgery because of the influence of many different intertwined factors.
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Affiliation(s)
- Angélique Volfart
- CNRS, CRAN UMR 7039, Université de Lorraine, Nancy, France
- Institute of Research in Psychological Science, Université Catholique de Louvain, Louvain-La-Neuve, Belgium
- School of Psychology and Counselling, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Bruno Rossion
- CNRS, CRAN UMR 7039, Université de Lorraine, Nancy, France
- Institute of Research in Psychological Science, Université Catholique de Louvain, Louvain-La-Neuve, Belgium
- CHRU-Nancy, Service de Neurologie, Université de Lorraine, Nancy, France
| | - Hélène Brissart
- CNRS, CRAN UMR 7039, Université de Lorraine, Nancy, France
- CHRU-Nancy, Service de Neurologie, Université de Lorraine, Nancy, France
| | - Thomas Busigny
- CNRS, CRAN UMR 7039, Université de Lorraine, Nancy, France
| | - Sophie Colnat-Coulbois
- CNRS, CRAN UMR 7039, Université de Lorraine, Nancy, France
- CHRU-Nancy, Service de Neurochirurgie, Université de Lorraine, Nancy, France
| | - Louis Maillard
- CNRS, CRAN UMR 7039, Université de Lorraine, Nancy, France
- CHRU-Nancy, Service de Neurologie, Université de Lorraine, Nancy, France
| | - Jacques Jonas
- CNRS, CRAN UMR 7039, Université de Lorraine, Nancy, France
- CHRU-Nancy, Service de Neurologie, Université de Lorraine, Nancy, France
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De Benedictis A, de Palma L, Rossi-Espagnet MC, Marras CE. Connectome-based approaches in pediatric epilepsy surgery: "State-of-the art" and future perspectives. Epilepsy Behav 2023; 149:109523. [PMID: 37944286 DOI: 10.1016/j.yebeh.2023.109523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 10/29/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
Modern epilepsy science has overcome the traditional interpretation of a strict region-specific origin of epilepsy, highlighting the involvement of wider patterns of altered neuronal circuits. In selected cases, surgery may constitute a valuable option to achieve both seizure freedom and neurocognitive improvement. Although epilepsy is now considered as a brain network disease, the most relevant literature concerning the "connectome-based" epilepsy surgery mainly refers to adults, with a limited number of studies dedicated to the pediatric population. In this review, the Authors summarized the main current available knowledge on the relevance of WM surgical anatomy in epilepsy surgery, the post-surgical modifications of brain structural connectivity and the related clinical impact of such modifications within the pediatric context. In the last part, possible implications and future perspectives of this approach have been discussed, especially concerning the optimization of surgical strategies and the predictive value of the epilepsy network analysis for planning tailored approaches, with the final aim of improving case selection, presurgical planning, intraoperative management, and postoperative results.
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Affiliation(s)
| | - Luca de Palma
- Epilepsy and Movement Disorders Neurology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
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Baxendale S. What are we really predicting with fMRI in epilepsy surgery? Epilepsy Behav 2023; 145:109298. [PMID: 37356225 DOI: 10.1016/j.yebeh.2023.109298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/27/2023]
Abstract
While memory and language functional magnetic resonance imaging (fMRI) paradigms are becoming evermore refined, the measures of outcome they predict following epilepsy surgery tend to remain single scores on pencil and paper tests that were developed decades ago and have been repeatedly shown to bear little relation to patients' subjective reports of memory problems in the real world. The growing imbalance between the increasing sophistication of the predictive paradigms on the one hand and the vintage measures of the outcome on the other in the fMRI epilepsy surgery literature threatens the clinical relevance of studies employing these technologies. This paper examines some of the core principles of assessing neuropsychological outcomes following epilepsy surgery and explores how these may be adapted and applied in fMRI study designs to maximize the clinical relevance of these studies.
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Affiliation(s)
- Sallie Baxendale
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, UCL, UK; University College Hospital, London, UK.
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Peng Y, Wang K, Liu C, Tan L, Zhang M, He J, Dai Y, Wang G, Liu X, Xiao B, Xie F, Long L. Cerebellar functional disruption and compensation in mesial temporal lobe epilepsy. Front Neurol 2023; 14:1062149. [PMID: 36816567 PMCID: PMC9932542 DOI: 10.3389/fneur.2023.1062149] [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: 10/05/2022] [Accepted: 01/06/2023] [Indexed: 02/05/2023] Open
Abstract
Background Cerebellar functional alterations are common in patients with mesial temporal lobe epilepsy (MTLE), which contribute to cognitive decline. This study aimed to deepen our knowledge of cerebellar functional alterations in patients with MTLE. Methods In this study, participants were recruited from an ongoing prospective cohort of 13 patients with left TLE (LTLE), 17 patients with right TLE (RTLE), and 30 healthy controls (HCs). Functional magnetic resonance imaging data were collected during a Chinese verbal fluency task. Group independent component (IC) analysis (group ICA) was applied to segment the cerebellum into six functionally separated networks. Functional connectivity was compared among cerebellar networks, cerebellar activation maps, and the centrality parameters of cerebellar regions. For cerebellar functional profiles with significant differences, we calculated their correlation with clinical features and neuropsychological scores. Result Compared to HCs and patients with LTLE, patients with RTLE had higher cerebellar functional connectivity between the default mode network (DMN) and the oculomotor network and lower cerebellar functional connectivity from the frontoparietal network (FPN) to the dorsal attention network (DAN) (p < 0.05, false discovery rate- (FDR-) corrected). Cerebellar degree centrality (DC) of the right lobule III was significantly higher in patients with LTLE compared to HC and patients with RTLE (p < 0.05, FDR-corrected). Higher cerebellar functional connectivity between the DMN and the oculomotor network, as well as lower cerebellar degree centrality of the right lobule III, was correlated with worse information test performance. Conclusion Cerebellar functional profiles were altered in MTLE and correlated with long-term memory in patients.
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Affiliation(s)
- Yiqian Peng
- Department of Radiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Kangrun Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China,Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Chaorong Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Langzi Tan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Min Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Jialinzi He
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Yuwei Dai
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Ge Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Xianghe Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Fangfang Xie
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, China,Fangfang Xie ✉
| | - Lili Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China,Clinical Research Center for Epileptic Disease of Hunan Province, Xiangya Hospital, Central South University, Changsha, China,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China,*Correspondence: Lili Long ✉
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Sugano H, Iimura Y, Suzuki H, Tamrakar S, Mitsuhashi T, Higo T, Ueda T, Nishioka K, Karagiozov K, Nakajima M. Can intraoperative electrocorticography be used to minimize the extent of resection in patients with temporal lobe epilepsy associated with hippocampal sclerosis? J Neurosurg 2022; 137:419-426. [PMID: 34861650 DOI: 10.3171/2021.9.jns211925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/21/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Tailored surgery to extensively resect epileptogenic lesions using intraoperative electrocorticography (ioECoG) may improve seizure outcomes. However, resection of large areas is associated with decreased memory function postoperatively. The authors assessed whether ioECoG could provide useful information on how to minimize the focus resection and obtain better seizure outcomes without memory deterioration. They examined the postoperative seizure-free period and memory alteration in a retrospective cohort of patients with mesial temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS) in whom the extent of removal was determined using ioECoG findings. METHODS The authors enrolled 82 patients with TLE associated with HS who were treated surgically. Transsylvian amygdalohippocampectomy was indicated as the first step. When visual inspection identified interictal epileptic discharges from the lateral temporal lobe on ioECoG, anterior temporal lobectomy (ATL) was eventually performed. The patients were divided into the selective amygdalohippocampectomy (SA, n = 40) and ATL (n = 42) groups. Postoperative seizure outcomes were assessed at 1, 2, 3, 5, and 7 years postoperatively using the International League Against Epilepsy classification. The Kaplan-Meier survival analysis was applied to evaluate the period of seizure recurrence between the SA and ATL groups. Factors attributed to seizure recurrence were analyzed using the Cox proportional hazards model, and they were as follows: epileptic focal laterality; age at seizure onset (< 10 or ≥ 10 years old); seizure frequency (more than weekly or less than weekly seizures); history of focal to bilateral tonic-clonic seizure; infectious etiology; and surgical procedure. The Wechsler Memory Scale-Revised was used to evaluate memory function pre- and postoperatively. RESULTS Seizure outcomes were significantly worse in the SA group than in the ATL group at 2 years postoperatively (p = 0.045). The International League Against Epilepsy class 1 outcomes at 7 years postoperatively in the SA and ATL groups were 63% and 81%, respectively. Kaplan-Meier analysis showed that seizure recurred significantly earlier in the SA group than in the ATL group (p = 0.031). The 2-way ANOVA analysis was used to compare the SA and ATL groups in each memory category, and revealed that there was no significant difference regardless of the side of surgery. CONCLUSIONS Visual assessment of ioECoG cannot be used as an indicator to minimize epileptic focus resection in patients with TLE associated with HS. ATL is more effective in obtaining seizure-free outcomes; however, both ATL and SA can preserve memory function.
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Johnson GW, Doss DJ, Englot DJ. Network dysfunction in pre and postsurgical epilepsy: connectomics as a tool and not a destination. Curr Opin Neurol 2022; 35:196-201. [PMID: 34799514 PMCID: PMC8891078 DOI: 10.1097/wco.0000000000001008] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Patients with focal drug-resistant epilepsy (DRE) sometimes continue to have seizures after surgery. Recently, there is increasing interest in using advanced network analyses (connectomics) to better understand this problem. Connectomics has changed the way researchers and clinicians view DRE, but it must be applied carefully in a hypothesis-driven manner to avoid spurious results. This review will focus on studies published in the last 18 months that have thoughtfully used connectomics to advance our fundamental understanding of network dysfunction in DRE - hopefully for the eventual direct benefit to patient care. RECENT FINDINGS Impactful recent findings have centered on using patient-specific differences in network dysfunction to predict surgical outcome. These works span functional and structural connectivity and include the modalities of functional and diffusion magnetic resonance imaging (MRI) and electrophysiology. Using functional MRI, many groups have described an increased functional segregation outside of the surgical resection zone in patients who fail surgery. Using electrophysiology, groups have reported network characteristics of resected tissue that suggest whether a patient will respond favorably to surgery. SUMMARY If we can develop accurate models to outline functional and structural network characteristics that predict failure of standard surgical approaches, then we can not only improve current clinical decision-making; we can also begin developing alternative treatments including network approaches to improve surgical success rates.
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Affiliation(s)
- Graham W. Johnson
- Department of Biomedical Engineering at Vanderbilt University
- Vanderbilt University Institute of Imaging Science at Vanderbilt University Medical Center
| | - Derek J. Doss
- Department of Biomedical Engineering at Vanderbilt University
- Vanderbilt University Institute of Imaging Science at Vanderbilt University Medical Center
| | - Dario J. Englot
- Department of Biomedical Engineering at Vanderbilt University
- Vanderbilt University Institute of Imaging Science at Vanderbilt University Medical Center
- Department of Neurological Surgery
- Department of Neurology
- Department of Radiology and Radiological Sciences at Vanderbilt University Medical Center
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Abstract
PURPOSE OF REVIEW We review significant advances in epilepsy imaging in recent years. RECENT FINDINGS Structural MRI at 7T with optimization of acquisition and postacquisition image processing increases the diagnostic yield but artefactual findings remain a challenge. MRI analysis from multiple sites indicates different atrophy patterns and white matter diffusion abnormalities in temporal lobe and generalized epilepsies, with greater abnormalities close to the presumed seizure source. Structural and functional connectivity relate to seizure spread and generalization; longitudinal studies are needed to clarify the causal relationship of these associations. Diffusion MRI may help predict surgical outcome and network abnormalities extending beyond the epileptogenic zone. Three-dimensional multimodal imaging can increase the precision of epilepsy surgery, improve seizure outcome and reduce complications. Language and memory fMRI are useful predictors of postoperative deficits, and lead to risk minimization. FDG PET is useful for clinical studies and specific ligands probe the pathophysiology of neurochemical fluxes and receptor abnormalities. SUMMARY Improved structural MRI increases detection of abnormalities that may underlie epilepsy. Diffusion, structural and functional MRI indicate the widespread associations of epilepsy syndromes. These can assist stratification of surgical outcome and minimize risk. PET has continued utility clinically and for research into the pathophysiology of epilepsies.
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Affiliation(s)
- John S Duncan
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London
- MRI Unit, Chalfont Centre for Epilepsy, Chalfont St Peter, UK
| | - Karin Trimmel
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London
- MRI Unit, Chalfont Centre for Epilepsy, Chalfont St Peter, UK
- Department of Neurology, Medical University of Vienna, Vienna, Austria
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Banjac S, Roger E, Cousin E, Mosca C, Minotti L, Krainik A, Kahane P, Baciu M. Mapping of Language-and-Memory Networks in Patients With Temporal Lobe Epilepsy by Using the GE2REC Protocol. Front Hum Neurosci 2022; 15:752138. [PMID: 35069148 PMCID: PMC8772037 DOI: 10.3389/fnhum.2021.752138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 12/13/2021] [Indexed: 11/17/2022] Open
Abstract
Preoperative mapping of language and declarative memory functions in temporal lobe epilepsy (TLE) patients is essential since they frequently encounter deterioration of these functions and show variable degrees of cerebral reorganization. Due to growing evidence on language and declarative memory interdependence at a neural and neuropsychological level, we propose the GE2REC protocol for interactive language-and-memory network (LMN) mapping. GE2REC consists of three inter-related tasks, sentence generation with implicit encoding (GE) and two recollection (2REC) memory tasks: recognition and recall. This protocol has previously been validated in healthy participants, and in this study, we showed that it also maps the LMN in the left TLE (N = 18). Compared to healthy controls (N = 19), left TLE (LTLE) showed widespread inter- and intra-hemispheric reorganization of the LMN through reduced activity of regions engaged in the integration and the coordination of this meta-network. We also illustrated how this protocol could be implemented in clinical practice individually by presenting two case studies of LTLE patients who underwent efficient surgery and became seizure-free but showed different cognitive outcomes. This protocol can be advantageous for clinical practice because it (a) is short and easy to perform; (b) allows brain mapping of essential cognitive functions, even at an individual level; (c) engages language-and-memory interaction allowing to evaluate the integrative processes within the LMN; (d) provides a more comprehensive assessment by including both verbal and visual modalities, as well as various language and memory processes. Based on the available postsurgical data, we presented preliminary results obtained with this protocol in LTLE patients that could potentially inform the clinical practice. This implies the necessity to further validate the potential of GE2REC for neurosurgical planning, along with two directions, guiding resection and describing LMN neuroplasticity at an individual level.
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Affiliation(s)
- Sonja Banjac
- Université Grenoble Alpes, CNRS LPNC UMR 5105, Grenoble, France
| | - Elise Roger
- Université Grenoble Alpes, CNRS LPNC UMR 5105, Grenoble, France
| | - Emilie Cousin
- Université Grenoble Alpes, CNRS LPNC UMR 5105, Grenoble, France
- Université Grenoble Alpes, UMS IRMaGe CHU Grenoble, Grenoble, France
| | - Chrystèle Mosca
- Université Grenoble Alpes, Grenoble Institute of Neuroscience ‘Synchronisation et modulation des réseaux neuronaux dans l’épilepsie’ & Neurology Department, Grenoble, France
| | - Lorella Minotti
- Université Grenoble Alpes, Grenoble Institute of Neuroscience ‘Synchronisation et modulation des réseaux neuronaux dans l’épilepsie’ & Neurology Department, Grenoble, France
| | - Alexandre Krainik
- Université Grenoble Alpes, UMS IRMaGe CHU Grenoble, Grenoble, France
| | - Philippe Kahane
- Université Grenoble Alpes, Grenoble Institute of Neuroscience ‘Synchronisation et modulation des réseaux neuronaux dans l’épilepsie’ & Neurology Department, Grenoble, France
| | - Monica Baciu
- Université Grenoble Alpes, CNRS LPNC UMR 5105, Grenoble, France
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