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Iktimal A, Spencer DD, Alkawadri R. Optimized Multilayer Perceptron for Sensorimotor Functional Mapping Based on a Few Minutes of Intracranial Electroencephalogram Data. Ann Neurol 2024. [PMID: 38506405 DOI: 10.1002/ana.26915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 03/05/2024] [Accepted: 03/05/2024] [Indexed: 03/21/2024]
Abstract
Using 6-minute free-running intracranial-electroencephalogram (icEEG) during sleep, an optimized multilayer perceptron (MLP) neural network accurately maps the sensorimotor cortex (SM) and identifies the anterior lip of the central sulcus (CS) in intractable epilepsy patients. We calculated 6 performance metrics to evaluate the MLP's efficacy: accuracy, area under the curve (AUC), recall, precision, F1-scores, and specificity. Each layer had 4 neurons with hyperbolic TanH activation function and 4 with Gaussian distribution function. Conventional 10-fold cross-validation was used. Feature extension (ε) and weighted imbalanced data (w) improved MLP performance. ANN NEUROL 2024.
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Affiliation(s)
- Alwan Iktimal
- Human Brain Mapping Program, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Dennis D Spencer
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT
| | - Rafeed Alkawadri
- Human Brain Mapping Program, University of Pittsburgh Medical Center, Pittsburgh, PA
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Mahgoub R, Bayram AK, Spencer DD, Alkawadri R. Functional parcellation of the cingulate gyrus by electrical cortical stimulation: a synthetic literature review and future directions. J Neurol Neurosurg Psychiatry 2024:jnnp-2023-332246. [PMID: 38242679 DOI: 10.1136/jnnp-2023-332246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 12/30/2023] [Indexed: 01/21/2024]
Abstract
BACKGROUND The cingulate gyrus (CG), a brain structure above the corpus callosum, is recognised as part of the limbic system and plays numerous vital roles. However, its full functional capacity is yet to be understood. In recent years, emerging evidence from imaging modalities, supported by electrical cortical stimulation (ECS) findings, has improved our understanding. To our knowledge, there is a limited number of systematic reviews of the cingulate function studied by ECS. We aim to parcellate the CG by reviewing ECS studies. DESIGN/METHODS We searched PubMed and Embase for studies investigating CG using ECS. A total of 30 studies met the inclusion criteria. We evaluated the ECS responses across the cingulate subregions and summarised the reported findings. RESULTS We included 30 studies (totalling 887 patients, with a mean age of 31.8±9.8 years). The total number of electrodes implanted within the cingulate was 3028 electrode contacts; positive responses were obtained in 941 (31.1%, median percentages, 32.3%, IQR 22.2%-64.3%). The responses elicited from the CG were as follows. Simple motor (8 studies, 26.7 %), complex motor (10 studies, 33.3%), gelastic with and without mirth (7 studies, 23.3%), somatosensory (9 studies, 30%), autonomic (11 studies, 36.7 %), psychic (8 studies, 26.7%) and vestibular (3 studies, 10%). Visual and speech responses were also reported. Despite some overlap, the results indicate that the anterior cingulate cortex is responsible for most emotional, laughter and autonomic responses, while the middle cingulate cortex controls most complex motor behaviours, and the posterior cingulate cortex (PCC) regulates visual, among various other responses. Consistent null responses have been observed across different regions, emphasising PCC. CONCLUSIONS Our results provide a segmental mapping of the functional properties of CG, helping to improve precision in the surgical planning of epilepsy.
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Affiliation(s)
- Rawan Mahgoub
- Department of Neurology, The University of Pittsburgh Medical Center (UPMC), Pittsburgh, Pennsylvania, USA
| | - Ayse Kacar Bayram
- Department of Pediatrics, Division of Pediatric Neurology, University of Health Sciences, Kayseri City Hospital, Kayseri, Turkey
| | - Dennis D Spencer
- Department of Neurosurgery, Yale School of Medicine, New Haven, Connecticut, USA
| | - Rafeed Alkawadri
- Department of Neurology, The University of Pittsburgh Medical Center (UPMC), Pittsburgh, Pennsylvania, USA
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Alkawadri R. Respiratory therapy mimicking electrographic seizures. Acta Neurol Belg 2023; 123:1973-1974. [PMID: 36115916 DOI: 10.1007/s13760-022-02088-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 09/01/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Rafeed Alkawadri
- Department of Neurology, and Human Brain Mapping Program, School of Medicine Pittsburgh, University of Pittsburgh Medical Center, 3471 Fifth avenue LKB eighth floor, Pittsburgh, PA, 15213, USA.
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Plute TJ, Spencer DD, Alkawadri R. Age-dependent vestibular cingulate-cerebral network underlying gravitational perception: a cross-sectional multimodal study. Brain Inform 2022; 9:30. [PMID: 36542188 PMCID: PMC9772366 DOI: 10.1186/s40708-022-00176-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 10/26/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND OBJECTIVES The cingulate gyrus (CG) is a frequently studied yet not wholly understood area of the human cerebrum. Previous studies have implicated CG in different adaptive cognitive-emotional functions and fascinating or debilitating symptoms. We describe an unusual loss of gravity perception/floating sensation in consecutive persons with drug-resistant epilepsy undergoing electrical cortical stimulation (ECS), network analysis, and network robustness mapping. METHODS Using Intracranial-EEG, Granger causality analysis, cortico-cortical evoked potentials, and fMRI, we explicate the functional networks arising from this phenomenon's anterior, middle, and posterior cingulate cortex. RESULTS Fifty-four icEEG cases from 2013 to 2019 were screened. In 40.7% of cases, CG was sampled and in 22.2% the sampling was bilateral. ECS mapping was carried out in 18.5% of the entire cohort and 45.4% of the cingulate sampled cases. Five of the ten CG cases experienced symptoms during stimulation. A total of 1942 electrodes were implanted with a median number of 182 electrode contacts per patient (range: 106-274). The electrode contacts sampled all major cortex regions. Sixty-three contacts were within CG. Of those, 26 were electrically stimulated; 53.8% of the stimulated contacts produced positive responses, whereas 46.2% produced no observable responses. Our study reports a unique perceptive phenomenon of a subjective sense of weightlessness/floating sensation triggered by anterior and posterior CG stimulation, in 30% of cases and 21.42% of electrode stimulation sites. Notable findings include functional connections between the insula, the posterior and anterior cingulate cortex, and networks between the middle cingulate and the frontal and temporal lobes and the cerebellum. We also postulate a vestibular-cerebral-cingulate network responsible for the perception of gravity while suggesting that cingulate functional connectivity follows a long-term developmental trajectory as indicated by a robust, positive correlation with age and the extent of Granger connectivity (r = 0.82, p = 0.0035). DISCUSSION We propose, in conjunction with ECS techniques, that a better understanding of the underlying gravity perception networks can lead to promising neuromodulatory clinical applications. CLASSIFICATION OF EVIDENCE This study provides Class II evidence for CG's involvement in the higher order processing of gravity perception and related actions.
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Affiliation(s)
- Tritan J Plute
- School of Medicine, Department of Neurology, University of Pittsburgh, 3471 Fifth Avenue, LKB 8Th Floor, Suite 815.05, Pittsburgh, PA, 15213, USA
| | - Dennis D Spencer
- Department of Neurosurgery, Yale School of Medicine, New Haven, 06520-8062, USA
| | - Rafeed Alkawadri
- School of Medicine, Department of Neurology, University of Pittsburgh, 3471 Fifth Avenue, LKB 8Th Floor, Suite 815.05, Pittsburgh, PA, 15213, USA.
- Department of Neurology, Yale School of Medicine, New Haven, 06520-8018, USA.
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Alkawadri R, Enatsu R, Hämäläinen M, Bagić A. Editorial: Magnetoencephalography: Methodological innovation paves the way for scientific discoveries and new clinical applications. Front Neurol 2022; 13:1056301. [PMID: 36504656 PMCID: PMC9731220 DOI: 10.3389/fneur.2022.1056301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 10/13/2022] [Indexed: 11/25/2022] Open
Affiliation(s)
- Rafeed Alkawadri
- University of Pittsburgh Comprehensive Epilepsy Center (UPCEC), Department of Neurology, University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, United States,*Correspondence: Rafeed Alkawadri ; https://www.humanbrainmapping.net/contactus
| | - Rei Enatsu
- Department of Neurosurgery, Sapporo Medical University, Sapporo, Japan
| | - Matti Hämäläinen
- Department of Radiology, Harvard Medical School, Boston, MA, United States,Department of Neuroscience and Biomedical Engineering, School of Science, Aalto University, Espoo, Finland
| | - Anto Bagić
- University of Pittsburgh Comprehensive Epilepsy Center (UPCEC), Department of Neurology, University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, United States
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Alkawadri R, Zaveri HP, Sheth KN, Spencer DD. Passive localization of the central sulcus during sleep based on intracranial EEG. Cereb Cortex 2022; 32:3726-3735. [PMID: 34921723 PMCID: PMC9764437 DOI: 10.1093/cercor/bhab443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 10/30/2021] [Accepted: 11/09/2021] [Indexed: 11/14/2022] Open
Abstract
We test the performance of a novel operator-independent EEG-based method for passive identification of the central sulcus (CS) and sensorimotor (SM) cortex. We studied seven patients with intractable epilepsy undergoing intracranial EEG (icEEG) monitoring, in whom CS localization was accomplished by standard methods. Our innovative approach takes advantage of intrinsic properties of the primary motor cortex (MC), which exhibits enhanced icEEG band-power and coherence across the CS. For each contact, we computed a composite power, coherence, and entropy values for activity in the high gamma band (80-115) Hz of 6-10 min of NREM sleep. Statistically transformed EEG data values that did not reach a threshold (th) were set to 0. We computed a metric M based on the transformed values and the mean Euclidian distance of each contact from contacts with Z-scores higher than 0. The last step was implemented to accentuate local network activity. The SM cortex exhibited higher EEG-band-power than non-SM cortex (P < 0.0002). There was no significant difference between the motor/premotor and sensory cortices (P < 0.47). CS was localized in all patients with 0.4 < th < 0.6. The primary hand and leg motor areas showed the highest metric values followed by the tongue motor area. Higher threshold values were specific (94%) for the anterior bank of the CS but not sensitive (42%). Intermediate threshold values achieved an acceptable trade-off (0.4: 89% specific and 70% sensitive).
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Affiliation(s)
- Rafeed Alkawadri
- Address correspondence to Rafeed Alkawadri, Human Brain Mapping Program, University of Pittsburgh Medical Center, Pittsburgh, PA 15123, USA.
| | - Hitten P Zaveri
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Kevin N Sheth
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Dennis D Spencer
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
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Pilato MS, Urban A, Alkawadri R, Barot NV, Castellano JF, Rajasekaran V, Bagić AI, Fong-Isariyawongse JS. EEG Findings in Coronavirus Disease. J Clin Neurophysiol 2022; 39:159-165. [PMID: 32639251 DOI: 10.1097/wnp.0000000000000752] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Neurologic manifestations of coronavirus disease (COVID-19) such as encephalopathy and seizures have been described. To our knowledge, detailed EEG findings in COVID-19 have not yet been reported. This report adds to the scarce body of evidence. METHODS We identified eight COVID-19 positive patients who underwent EEG monitoring in our hospital system. RESULTS EEGs were most commonly ordered for an altered level of consciousness, a nonspecific neurologic manifestation. We observed generalized background slowing in all patients and generalized epileptiform discharges with triphasic morphology in three patients. Focal electrographic seizures were observed in one patient with a history of focal epilepsy and in another patient with no such history. Five of eight patients had a previous diagnosis of epilepsy, suggesting that pre-existing epilepsy can be a potential risk factor for COVID-19-associated neurological manifestations. Five of eight patients who underwent EEG experienced a fatal outcome of infection. CONCLUSIONS Our findings underscore previous observations that neurologic manifestations are common in severe cases. COVID-19 patients with epilepsy may have an increased risk of neurological manifestations and abnormal EEG.
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Affiliation(s)
- Madison S Pilato
- University of Pittsburgh Comprehensive Epilepsy Center, Department of Neurology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, U.S.A
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Sheikh MM, Koubeissi MZ, Spencer DD, Alkawadri R. The Neural Networks Underlying the Illusion of Time Dilation. Ann Neurol 2021; 91:295-297. [PMID: 34841572 DOI: 10.1002/ana.26277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 11/24/2021] [Accepted: 11/26/2021] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Dennis D Spencer
- Department of Neurosurgery, School of Medicine, Yale University, New Haven, CT
| | - Rafeed Alkawadri
- Human Brain Mapping Program, University of Pittsburgh Medical Center, Pittsburgh, PA
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Kacar Bayram A, Yan Q, Isitan C, Rao S, Spencer DD, Alkawadri R. Effect of anesthesia on electrocorticography for localization of epileptic focus: Literature review and future directions. Epilepsy Behav 2021; 118:107902. [PMID: 33819715 DOI: 10.1016/j.yebeh.2021.107902] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 11/20/2022]
Abstract
Intraoperative electrocorticography (ECoG) is a useful technique to guide resections in epilepsy surgery and is mostly performed under general anesthesia. In this systematic literature review, we seek to investigate the effect of anesthetic agents on the quality and reliability of ECoG for localization of the epileptic focus. We conducted a systematic search using PubMed and EMBASE until January 2019, aiming to review the effects of anesthesia on ECoG yield. Fifty-eight studies were included from 1016 reviewed. There are favorable reports for dexmedetomidine and remifentanil during ECoG recording. There is inadequate, or sometimes conflicting, evidence to support using enflurane, isoflurane, sevoflurane, and propofol. There is evidence to avoid halothane, nitrous oxide, etomidate, ketamine, thiopental, methohexital, midazolam, fentanyl, and alfentanil due to undesired effects. Depth of anesthesia, intraoperative awareness, and surgical outcomes were not consistently evaluated. Available studies provide helpful information about the effect of anesthesia on ECoG to localize the epileptic focus. The proper use of anesthetic agents and careful dose titration, and effective communication between the neurophysiologist and anesthesiologist based on ECoG activity are essential in optimizing recordings. Anesthesia is a crucial variate to consider in the design of studies investigating ECoG and related biomarkers.
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Affiliation(s)
- Ayse Kacar Bayram
- Comprehensive Epilepsy Center, Dept. of Neurology, School of Medicine, Yale University, Yale New Haven Hospital, New Haven, CT, United States; Department of Pediatrics, Division of Pediatric Neurology, University of Health Sciences, Kayseri City Hospital, Kayseri, Turkey.
| | - Qi Yan
- Comprehensive Epilepsy Center, Dept. of Neurology, School of Medicine, Yale University, Yale New Haven Hospital, New Haven, CT, United States
| | - Cigdem Isitan
- Human Brain Mapping Program, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Shilpa Rao
- Department of Anesthesiology, School of Medicine, Yale University, New Haven, CT, United States
| | - Dennis D Spencer
- Comprehensive Epilepsy Center, Dept. of Neurology, School of Medicine, Yale University, Yale New Haven Hospital, New Haven, CT, United States
| | - Rafeed Alkawadri
- Comprehensive Epilepsy Center, Dept. of Neurology, School of Medicine, Yale University, Yale New Haven Hospital, New Haven, CT, United States; Human Brain Mapping Program, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
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Isitan C, Yan Q, Spencer DD, Alkawadri R. Brief history of electrical cortical stimulation: A journey in time from Volta to Penfield. Epilepsy Res 2020; 166:106363. [PMID: 32673971 DOI: 10.1016/j.eplepsyres.2020.106363] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/26/2020] [Accepted: 05/05/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To recount the evolution of Electrical Cortical Stimulation (ECS) in localizing brain functions with an emphasis on epilepsy, and a discussion of related instruments and personnel. DESIGN/METHODS Literature review through historical archives implementing chain-referral sampling. RESULTS There were important milestones leading to the incorporation of ECS into practice: 1. Aldini's (1802) first known stimulation of exposed brain to defend Galvani's views on excitability in the frog-leg experiment against Volta's, ironically by employing the Voltaic pile. 2. Animal experiments in the 19th-century to study the brain and to optimize the procedure: Rolando (1809) reported on motor induction, Fritsch and Hitzig (ca. 1870) introduced the concepts of bipolar and threshold stimulation, and Ferrier (1873) generated reproducible homunculi in animals. 3. Parallel to 2, advances were made based on clinical observations by Bravais, Todd, Jackson, and Broca among others. 4. First known stimulation in conscious humans by Bartholow (1874) led to catastrophic outcomes. Horsley (1886) performed first intraoperative stimulation on Jackson's epileptic patient. 5. Advances accelerated in the first-half of the 20th century with Cushing (1909) performing first awake-craniotomy eliciting sensory responses to Penfield's work culminating in standardization of clinical use and generation of detailed maps including the famous sensory-motor homunculi. Parallel advances in instrumentation were made from the Leyden jar (1745) to present customizable current-controlled stimulators. CONCLUSIONS ECS is commonly used in neurosurgery for localization of brain functions and is the benchmark for research studies. Significant leaps have been made since ECS first used in the 19th century. It evolved to remain the gold standard for localization of human brain functions in the 21st century.
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Affiliation(s)
- Cigdem Isitan
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States; Human Brain Mapping Program, Yale University, New Haven, CT, United States
| | - Qi Yan
- Comprehensive Epilepsy Center, Yale University, New Haven, CT, United States; Human Brain Mapping Program, Yale University, New Haven, CT, United States
| | - Dennis D Spencer
- Comprehensive Epilepsy Center, Yale University, New Haven, CT, United States; Department of Neurosurgery, Yale University, New Haven, CT, United States
| | - Rafeed Alkawadri
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States; Comprehensive Epilepsy Center, Yale University, New Haven, CT, United States; Human Brain Mapping Program, Yale University, New Haven, CT, United States.
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Herman WX, Smith RE, Kronemer SI, Watsky RE, Chen WC, Gober LM, Touloumes GJ, Khosla M, Raja A, Horien CL, Morse EC, Botta KL, Hirsch LJ, Alkawadri R, Gerrard JL, Spencer DD, Blumenfeld H. A Switch and Wave of Neuronal Activity in the Cerebral Cortex During the First Second of Conscious Perception. Cereb Cortex 2020; 29:461-474. [PMID: 29194517 DOI: 10.1093/cercor/bhx327] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Indexed: 12/17/2022] Open
Abstract
Conscious perception occurs within less than 1 s. To study events on this time scale we used direct electrical recordings from the human cerebral cortex during a conscious visual perception task. Faces were presented at individually titrated visual threshold for 9 subjects while measuring broadband 40-115 Hz gamma power in a total of 1621 intracranial electrodes widely distributed in both hemispheres. Surface maps and k-means clustering analysis showed initial activation of visual cortex for both perceived and non-perceived stimuli. However, only stimuli reported as perceived then elicited a forward-sweeping wave of activity throughout the cerebral cortex accompanied by large-scale network switching. Specifically, a monophasic wave of broadband gamma activation moves through bilateral association cortex at a rate of approximately 150 mm/s and eventually reenters visual cortex for perceived but not for non-perceived stimuli. Meanwhile, the default mode network and the initial visual cortex and higher association cortex networks are switched off for the duration of conscious stimulus processing. Based on these findings, we propose a new "switch-and-wave" model for the processing of consciously perceived stimuli. These findings are important for understanding normal conscious perception and may also shed light on its vulnerability to disruption by brain disorders.
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Affiliation(s)
- Wendy X Herman
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Rachel E Smith
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Sharif I Kronemer
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Rebecca E Watsky
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - William C Chen
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Leah M Gober
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - George J Touloumes
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Meenakshi Khosla
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Anusha Raja
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Corey L Horien
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Elliot C Morse
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Katherine L Botta
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Lawrence J Hirsch
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Rafeed Alkawadri
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Jason L Gerrard
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Dennis D Spencer
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Hal Blumenfeld
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
- Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
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12
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Alkawadri R, Burgess RC, Kakisaka Y, Mosher JC, Alexopoulos AV. Assessment of the Utility of Ictal Magnetoencephalography in the Localization of the Epileptic Seizure Onset Zone. JAMA Neurol 2019; 75:1264-1272. [PMID: 29889930 DOI: 10.1001/jamaneurol.2018.1430] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Importance Literature on ictal magnetoencephalography (MEG) in clinical practice and the relationship to other modalities is limited because of the brevity of routine studies. Objective To investigate the utility and reliability of ictal MEG in the localization of the epileptogenic zone. Design, Setting, and Participants A retrospective medical record review and prospective analysis of a novel ictal rhythm analysis method was conducted at a tertiary epilepsy center with a wide base of referrals for epilepsy surgery evaluation and included consecutive cases of patients who experienced epileptic seizures during routine MEG studies from March 2008 to February 2012. A total of 377 studies screened. Data were analyzed from November 2011 to October 2015. Main Outcomes and Measures Presurgical workup and interictal and ictal MEG data were reviewed. The localizing value of using extended-source localization of a narrow band identified visually at onset was analyzed. Results Of the 44 included patients, the mean (SD) age at the time of recording was 19.3 (14.9) years, and 25 (57%) were male. The mean duration of recording was 51.2 minutes. Seizures were provoked by known triggers in 3 patients and were spontaneous otherwise. Twenty-five patients (57%) had 1 seizure, 6 (14%) had 2, and 13 (30%) had 3 or more. Magnetoencephalography single equivalent current dipole analysis was possible in 29 patients (66%), of whom 8 (28%) had no clear interictal discharges. Sublobar concordance between ictal and interictal dipoles was seen in 18 of 21 patients (86%). Three patients (7%) showed clear ictal MEG patterns without electroencephalography changes. Ictal MEG dipoles correlated with the lobe of onset in 7 of 8 patients (88%) who underwent intracranial electroencephalography evaluations. Reasons for failure to identify ictal dipoles included diffuse or poor dipolar ictal patterns, no MEG changes, and movement artifact. Resection of areas containing a minimum-norm estimate of a narrow band at onset, not single equivalent current dipole, was associated with sustained seizure freedom. Conclusions and Significance Ictal MEG data can provide reliable localization, including in cases that are difficult to localize by other modalities. These findings support the use of extended-source localization for seizures recorded during MEG.
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Affiliation(s)
- Rafeed Alkawadri
- The Epilepsy Center at Cleveland Clinic Foundation, Cleveland, Ohio.,Yale Comprehensive Epilepsy Center, School of Medicine, Yale University, New Haven, Connecticut.,Yale Human Brain Mapping Program, School of Medicine, Yale University, New Haven, Connecticut
| | | | - Yosuke Kakisaka
- The Epilepsy Center at Cleveland Clinic Foundation, Cleveland, Ohio.,The Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - John C Mosher
- The Epilepsy Center at Cleveland Clinic Foundation, Cleveland, Ohio
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13
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Yan Q, Gaspard N, Zaveri HP, Blumenfeld H, Hirsch LJ, Spencer DD, Alkawadri R. The connectivity index: an effective metric for grading epileptogenicity. J Neurosurg 2019; 133:1-8. [PMID: 31561212 DOI: 10.3171/2019.4.jns195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/05/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The aim of this study was to investigate the performance of a metric of functional connectivity to classify and grade the excitability of brain regions based on evoked potentials in response to single-pulse electrical stimulation (SPES). METHODS Patients who underwent 1-Hz frequency stimulation at prospectively selected contacts between 2003 and 2014 at the Yale Comprehensive Epilepsy Center were included. The stimulated contacts were classified as the seizure onset zone (SOZ), highly irritative zone (possibly epileptogenic irritative zone [IZp]), and control contacts not involved in the epileptic activity. Response contacts were classified as SOZ, active interictal irritative zone (IZ), quiet, or other. The normalized number of responses was defined as the number of contacts with any evoked responses divided by the total number of recorded contacts, and the normalized distance is the ratio of the average distance between the site of stimulation and sites of evoked responses to the average distances between the site of stimulation and all other recording contacts. A new metric that the authors labeled the connectivity index (CI) is defined as the product of the 2 values. RESULTS A total of 57 stimulation sessions in 22 patients were analyzed. The CI of the SOZ was higher than for control contacts (median CI of 0.74 vs 0.16, p = 0.0002). The evoked responses after stimulation of SOZ were seen at further distances compared to control (median normalized distance 0.96 vs 0.62, p = 0.0005). It was 1.8 times more likely that a response would be recorded at the SOZ than in nonepileptic contacts after stimulation of a control site. Habitual seizures were triggered in 27% of patients and 35% of SOZ contacts (median stimulation intensity 4 mA) but in none of the control or IZp contacts. Non-SOZ contacts in multifocal or poor surgical outcome cases had a higher CI than non-SOZ contacts in patients with localizable onsets (median CI of 0.5 vs 0.12, p = 0.04). There was a correlation between the stimulation current intensity and the normalized number of evoked responses (r = + 0.49, p = 0.01) but not with distance (r = + 0.1, p = 0.64). CONCLUSIONS The authors found enhanced connectivity when stimulating the SOZ compared to stimulating control contacts; responses were more distant as well. Habitual auras and seizures provoked by SPES were highly predictive of brain sites involved in seizure generation.
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Affiliation(s)
- Qi Yan
- Departments of1Neurology and
- 3The Human Brain Mapping Program, Yale University, New Haven, Connecticut
| | - Nicolas Gaspard
- Departments of1Neurology and
- 3The Human Brain Mapping Program, Yale University, New Haven, Connecticut
- 4Hôpital Erasme-ULB, Cliniques Universitaires de Bruxelles, Bruxelles, Belgium; and
| | | | - Hal Blumenfeld
- Departments of1Neurology and
- 2Neurosurgery, School of Medicine, and
| | | | | | - Rafeed Alkawadri
- Departments of1Neurology and
- 3The Human Brain Mapping Program, Yale University, New Haven, Connecticut
- 5Department of Neurology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
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Alkawadri R. Brain-Computer Interface (BCI) Applications in Mapping of Epileptic Brain Networks Based on Intracranial-EEG: An Update. Front Neurosci 2019; 13:191. [PMID: 30971871 PMCID: PMC6446441 DOI: 10.3389/fnins.2019.00191] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 02/18/2019] [Indexed: 01/20/2023] Open
Abstract
The main applications of the Brain-Computer Interface (BCI) have been in the domain of rehabilitation, control of prosthetics, and in neuro-feedback. Only a few clinical applications presently exist for the management of drug-resistant epilepsy. Epilepsy surgery can be a life-changing procedure in the subset of millions of patients who are medically intractable. Recording of seizures and localization of the Seizure Onset Zone (SOZ) in the subgroup of "surgical" patients, who require intracranial-EEG (icEEG) evaluations, remain to date the best available surrogate marker of the epileptogenic tissue. icEEG presents certain risks and challenges making it a frontier that will benefit from optimization. Despite the presentation of several novel biomarkers for the localization of epileptic brain regions (HFOs-spikes vs. Spikes for instance), integration of most in practices is not at the prime time as it requires a degree of knowledge about signal and computation. The clinical care remains inspired by the original practices of recording the seizures and expert visual analysis of rhythms at onset. It is becoming increasingly evident, however, that there is more to infer from the large amount of EEG data sampled at rates in the order of less than 1 ms and collected over several days of invasive EEG recordings than commonly done in practice. This opens the door for interesting areas at the intersection of neuroscience, computation, engineering and clinical care. Brain-Computer interface (BCI) has the potential of enabling the processing of a large amount of data in a short period of time and providing insights that are not possible otherwise by human expert readers. Our practices suggest that implementation of BCI and Real-Time processing of EEG data is possible and suitable for most standard clinical applications, in fact, often the performance is comparable to a highly qualified human readers with the advantage of producing the results in real-time reliably and tirelessly. This is of utmost importance in specific environments such as in the operating room (OR) among other applications. In this review, we will present the readers with potential targets for BCI in caring for patients with surgical epilepsy.
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Affiliation(s)
- Rafeed Alkawadri
- Human Brain Mapping Laboratory, Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
- Yale Human Brain Mapping Program, Yale University, New Haven, CT, United States
- The Department of Neurology, School of Medicine, Yale University, New Haven, CT, United States
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15
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Benjamin CFA, Dhingra I, Li AX, Blumenfeld H, Alkawadri R, Bickel S, Helmstaedter C, Meletti S, Bronen RA, Warfield SK, Peters JM, Reutens D, Połczyńska MM, Hirsch LJ, Spencer DD. Presurgical language fMRI: Technical practices in epilepsy surgical planning. Hum Brain Mapp 2018; 39:4032-4042. [PMID: 29962111 PMCID: PMC6175127 DOI: 10.1002/hbm.24229] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/10/2018] [Accepted: 05/14/2018] [Indexed: 11/24/2022] Open
Abstract
Little is known about how language functional MRI (fMRI) is executed in clinical practice in spite of its widespread use. Here we comprehensively documented its execution in surgical planning in epilepsy. A questionnaire focusing on cognitive design, image acquisition, analysis and interpretation, and practical considerations was developed. Individuals responsible for collecting, analyzing, and interpreting clinical language fMRI data at 63 epilepsy surgical programs responded. The central finding was of marked heterogeneity in all aspects of fMRI. Most programs use multiple tasks, with a fifth routinely using 2, 3, 4, or 5 tasks with a modal run duration of 5 min. Variants of over 15 protocols are in routine use with forms of noun–verb generation, verbal fluency, and semantic decision‐making used most often. Nearly all aspects of data acquisition and analysis vary markedly. Neither of the two best‐validated protocols was used by more than 10% of respondents. Preprocessing steps are broadly consistent across sites, language‐related blood flow is most often identified using general linear modeling (76% of respondents), and statistical thresholding typically varies by patient (79%). The software SPM is most often used. fMRI programs inconsistently include input from experts with all required skills (imaging, cognitive assessment, MR physics, statistical analysis, and brain–behavior relationships). These data highlight marked gaps between the evidence supporting fMRI and its clinical application. Teams performing language fMRI may benefit from evaluating practice with reference to the best‐validated protocols to date and ensuring individuals trained in all aspects of fMRI are involved to optimize patient care.
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Affiliation(s)
| | - Isha Dhingra
- Yale Comprehensive Epilepsy Center, New Haven, Connecticut, USA
| | - Alexa X Li
- Quinnipiac University School of Medicine, North Haven, Connecticut, USA
| | - Hal Blumenfeld
- Yale Comprehensive Epilepsy Center, New Haven, Connecticut, USA
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16
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Quraishi I, Benjamin C, Spencer DD, Blumenfeld H, Alkawadri R. T02. Impairment of consciousness induced by electrical cortical stimulation: Under-reported phenomenon or a disease-specific condition? Clin Neurophysiol 2018. [DOI: 10.1016/j.clinph.2018.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Bayram A, Rao S, Spencer DD, Alkawadri R. T143. Effect of anesthesia on electrocorticography for localization of epileptic focus: Literature review and future directions. Clin Neurophysiol 2018. [DOI: 10.1016/j.clinph.2018.04.144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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19
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Alkawadri R, Zaveri HP, Gaspard N, Yan Q, Hirsch LJ, Spencer DD. T103. The connectivity index: A novel metric to grade epileptogenicity. Clin Neurophysiol 2018. [DOI: 10.1016/j.clinph.2018.04.104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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20
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Benjamin CFA, Li AX, Blumenfeld H, Constable RT, Alkawadri R, Bickel S, Helmstaedter C, Meletti S, Bronen R, Warfield SK, Peters JM, Reutens D, Połczyńska M, Spencer DD, Hirsch LJ. Presurgical language fMRI: Clinical practices and patient outcomes in epilepsy surgical planning. Hum Brain Mapp 2018. [PMID: 29528160 PMCID: PMC6033659 DOI: 10.1002/hbm.24039] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The goal of this study was to document current clinical practice and report patient outcomes in presurgical language functional MRI (fMRI) for epilepsy surgery. Epilepsy surgical programs worldwide were surveyed as to the utility, implementation, and efficacy of language fMRI in the clinic; 82 programs responded. Respondents were predominantly US (61%) academic programs (85%), and evaluated adults (44%), adults and children (40%), or children only (16%). Nearly all (96%) reported using language fMRI. Surprisingly, fMRI is used to guide surgical margins (44% of programs) as well as lateralize language (100%). Sites using fMRI for localization most often use a distance margin around activation of 10mm. While considered useful, 56% of programs reported at least one instance of disagreement with other measures. Direct brain stimulation typically confirmed fMRI findings (74%) when guiding margins, but instances of unpredicted decline were reported by 17% of programs and 54% reported unexpected preservation of function. Programs reporting unexpected decline did not clearly differ from those which did not. Clinicians using fMRI to guide surgical margins do not typically map known language‐critical areas beyond Broca's and Wernicke's. This initial data shows many clinical teams are confident using fMRI not only for language lateralization but also to guide surgical margins. Reported cases of unexpected language preservation when fMRI activation is resected, and cases of language decline when it is not, emphasize a critical need for further validation. Comprehensive studies comparing commonly‐used fMRI paradigms to predict stimulation mapping and post‐surgical language decline remain of high importance.
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Affiliation(s)
| | - Alexa X Li
- Quinnipiac University School of Medicine, 370 Bassett Rd, North Haven, CT, USA
| | - Hal Blumenfeld
- Yale University School of Medicine, 333 Cedar Ave, New Haven, CT, USA
| | - R Todd Constable
- Yale University School of Medicine, 333 Cedar Ave, New Haven, CT, USA
| | - Rafeed Alkawadri
- Yale University School of Medicine, 333 Cedar Ave, New Haven, CT, USA
| | | | | | - Stefano Meletti
- University of Modena and Reggio Emilia, Via Università, 4, Modena, MO, Italy
| | - Richard Bronen
- Yale University School of Medicine, 333 Cedar Ave, New Haven, CT, USA
| | | | | | - David Reutens
- The University of Queensland, St. Lucia QLD, Australia
| | | | - Dennis D Spencer
- Yale University School of Medicine, 333 Cedar Ave, New Haven, CT, USA
| | - Lawrence J Hirsch
- Yale University School of Medicine, 333 Cedar Ave, New Haven, CT, USA
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21
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Quraishi IH, Benjamin CF, Spencer DD, Blumenfeld H, Alkawadri R. Impairment of consciousness induced by bilateral electrical stimulation of the frontal convexity. Epilepsy Behav Case Rep 2017; 8:117-122. [PMID: 29204347 PMCID: PMC5707211 DOI: 10.1016/j.ebcr.2017.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 09/21/2017] [Accepted: 09/22/2017] [Indexed: 12/01/2022]
Abstract
We report a case of impairment of consciousness (IOC) induced by electrical cortical stimulation (ECS) of homologous regions within the lateral frontal convexities in a patient with medically intractable epilepsy. The patient had mixed features of idiopathic generalized and focal epilepsy. On intracranial EEG recording, interictal and ictal discharges showed a high degree of synchrony across widespread bilateral fronto-parietal areas. We identified regions in the lateral frontal lobes that reliably and produced loss of consciousness by ECS. This was accompanied by evoked EEG activity of admixed frequencies over the fronto-parietal, mesial frontal and temporal regions during stimulation and was not associated with after-discharges. Symptoms were immediately reversible upon cessation of stimulation. This finding suggests that focal cortical stimulation can disrupt widespread networks that underlie consciousness. Individuals with high degrees of speculated thalamo-frontal cortical connectivity might be more susceptible to this effect, and the findings highlight the importance of standardizing the testing of level of consciousness during mapping sessions. Although consciousness is commonly impaired in epileptic seizures, limited literature is available on loss of consciousness induced by electrical cortical stimulation (ECS) in humans undergoing intracranial EEG evaluations for localization of epileptic focus. One theory advocates the presence of consciousness ‘switch’ in subcortical structures. While this model is novel and simplistic, it has its inherent limitations. In this case study, we propose an alternative approach on the entity and discuss the complex circuits underlying it and correlate that with the electrophysiological findings and the pathophysiology of the phenotype of the disease and discuss potential causes for rarity of reports on the subject.
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Affiliation(s)
- Imran H Quraishi
- Department of Neurology, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA.,The Human Brain Mapping Program, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA
| | - Christopher F Benjamin
- Department of Neurology, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA.,Department of Neurosurgery, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA.,The Human Brain Mapping Program, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA
| | - Dennis D Spencer
- Department of Neurosurgery, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA
| | - Hal Blumenfeld
- Department of Neurology, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA.,Department of Neurosurgery, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA
| | - Rafeed Alkawadri
- Department of Neurology, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA.,The Human Brain Mapping Program, Yale Comprehensive Epilepsy Center, Yale School of Medicine, USA
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22
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Benjamin CF, Walshaw PD, Hale K, Gaillard WD, Baxter LC, Berl MM, Polczynska M, Noble S, Alkawadri R, Hirsch LJ, Constable RT, Bookheimer SY. Presurgical language fMRI: Mapping of six critical regions. Hum Brain Mapp 2017; 38:4239-4255. [PMID: 28544168 PMCID: PMC5518223 DOI: 10.1002/hbm.23661] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 02/01/2023] Open
Abstract
Language mapping is a key goal in neurosurgical planning. fMRI mapping typically proceeds with a focus on Broca's and Wernicke's areas, although multiple other language‐critical areas are now well‐known. We evaluated whether clinicians could use a novel approach, including clinician‐driven individualized thresholding, to reliably identify six language regions, including Broca's Area, Wernicke's Area (inferior, superior), Exner's Area, Supplementary Speech Area, Angular Gyrus, and Basal Temporal Language Area. We studied 22 epilepsy and tumor patients who received Wada and fMRI (age 36.4[12.5]; Wada language left/right/mixed in 18/3/1). fMRI tasks (two × three tasks) were analyzed by two clinical neuropsychologists who flexibly thresholded and combined these to identify the six regions. The resulting maps were compared to fixed threshold maps. Clinicians generated maps that overlapped significantly, and were highly consistent, when at least one task came from the same set. Cases diverged when clinicians prioritized different language regions or addressed noise differently. Language laterality closely mirrored Wada data (85% accuracy). Activation consistent with all six language regions was consistently identified. In blind review, three external, independent clinicians rated the individualized fMRI language maps as superior to fixed threshold maps; identified the majority of regions significantly more frequently; and judged language laterality to mirror Wada lateralization more often. These data provide initial validation of a novel, clinician‐based approach to localizing language cortex. They also demonstrate clinical fMRI is superior when analyzed by an experienced clinician and that when fMRI data is of low quality judgments of laterality are unreliable and should be withheld. Hum Brain Mapp 38:4239–4255, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Christopher F Benjamin
- Department of Neurology, Comprehensive Epilepsy Center, Yale School of Medicine, New Haven, Connecticut.,Department of Neurosurgery, Yale School of Medicine, New Haven, Connecticut
| | - Patricia D Walshaw
- UCLA Department of Psychiatry and Biobehavioral Sciences, Los Angeles, California
| | - Kayleigh Hale
- U.S. Department of Veterans Affairs, War Related Illness and Injury Study Center, Washington, DC
| | - William D Gaillard
- Center for Neuroscience Research, Children's National Health System, Washington, DC
| | - Leslie C Baxter
- Department of Neuroimaging Research, Barrow Neurological Institute, Phoenix, Arizona
| | - Madison M Berl
- Center for Neuroscience Research, Children's National Health System, Washington, DC
| | - Monika Polczynska
- UCLA Department of Psychiatry and Biobehavioral Sciences, Los Angeles, California.,Faculty of English, Adam Mickiewicz University, Poznań, Poland
| | - Stephanie Noble
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut
| | - Rafeed Alkawadri
- Department of Neurology, Comprehensive Epilepsy Center, Yale School of Medicine, New Haven, Connecticut
| | - Lawrence J Hirsch
- Department of Neurology, Comprehensive Epilepsy Center, Yale School of Medicine, New Haven, Connecticut
| | - R Todd Constable
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut
| | - Susan Y Bookheimer
- UCLA Department of Psychiatry and Biobehavioral Sciences, Los Angeles, California
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23
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Goncharova II, Alkawadri R, Gaspard N, Duckrow RB, Spencer DD, Hirsch LJ, Spencer SS, Zaveri HP. The relationship between seizures, interictal spikes and antiepileptic drugs. Clin Neurophysiol 2016; 127:3180-3186. [PMID: 27292227 DOI: 10.1016/j.clinph.2016.05.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 05/01/2016] [Accepted: 05/16/2016] [Indexed: 01/09/2023]
Abstract
OBJECTIVE A considerable decrease in spike rate accompanies antiepileptic drug (AED) taper during intracranial EEG (icEEG) monitoring. Since spike rate during icEEG monitoring can be influenced by surgery to place intracranial electrodes, we studied spike rate during long-term scalp EEG monitoring to further test this observation. METHODS We analyzed spike rate, seizure occurrence and AED taper in 130 consecutive patients over an average of 8.9days (range 5-17days). RESULTS We observed a significant relationship between time to the first seizure, spike rate, AED taper and seizure occurrence (F (3,126)=19.77, p<0.0001). A high spike rate was related to a longer time to the first seizure. Further, in a subset of 79 patients who experienced seizures on or after day 4 of monitoring, spike rate decreased initially from an on- to off-AEDs epoch (from 505.0 to 382.3 spikes per hour, p<0.00001), and increased thereafter with the occurrence of seizures. CONCLUSIONS There is an interplay between seizures, spikes and AEDs such that spike rate decreases with AED taper and increases after seizure occurrence. SIGNIFICANCE The direct relationship between spike rate and AEDs and between spike rate and time to the first seizure suggests that spikes are a marker of inhibition rather than excitation.
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Affiliation(s)
- Irina I Goncharova
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Rafeed Alkawadri
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Nicolas Gaspard
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Robert B Duckrow
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Dennis D Spencer
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Lawrence J Hirsch
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Susan S Spencer
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Hitten P Zaveri
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA.
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24
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Benjamin C, Walshaw P, Polczynska M, Hale K, Alkawadri R, Bookheimer S. NEUROPSYCHOLOGICAL DOMAINS: LANGUAGE AND APHASIAC-39A Clinical Model of Language for Presurgical Language Localization using fMRI. Arch Clin Neuropsychol 2015. [DOI: 10.1093/arclin/acv047.241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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25
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Benjamin C, Walshaw P, Polczynska M, Hale K, Alkawadri R, Bookheimer S. Epilepsy-4A Clinical Model of Language for Presurgical Language Localization using fMRI. Arch Clin Neuropsychol 2015. [DOI: 10.1093/arclin/acv046.08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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26
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Alkawadri R, Gaspard N, Goncharova II, Spencer DD, Gerrard JL, Zaveri H, Duckrow RB, Blumenfeld H, Hirsch LJ. The spatial and signal characteristics of physiologic high frequency oscillations. Epilepsia 2014; 55:1986-95. [PMID: 25470216 DOI: 10.1111/epi.12851] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To study the incidence, spatial distribution, and signal characteristics of high frequency oscillations (HFOs) outside the epileptic network. METHODS We included patients who underwent invasive evaluations at Yale Comprehensive Epilepsy Center from 2012 to 2013, had all major lobes sampled, and had localizable seizure onsets. Segments of non-rapid eye movement (NREM) sleep prior to the first seizure were analyzed. We implemented a semiautomated process to analyze oscillations with peak frequencies >80 Hz (ripples 80-250 Hz; fast ripples 250-500 Hz). A contact location was considered epileptic if it exhibited epileptiform discharges during the intracranial evaluation or was involved ictally within 5 s of seizure onset; otherwise it was considered nonepileptic. RESULTS We analyzed recordings from 1,209 electrode contacts in seven patients. The nonepileptic contacts constituted 79.1% of the total number of contacts. Ripples constituted 99% of total detections. Eighty-two percent of all HFOs were seen in 45.2% of the nonepileptic contacts (82.1%, 47%, 34.6%, and 34% of the occipital, parietal, frontal, and temporal nonepileptic contacts, respectively). The following sublobes exhibited physiologic HFOs in all patients: Perirolandic, basal temporal, and occipital subregions. The ripples from nonepileptic sites had longer duration, higher amplitude, and lower peak frequency than ripples from epileptic sites. A high HFO rate (>1/min) was seen in 110 nonepileptic contacts, of which 68.2% were occipital. Fast ripples were less common, seen in nonepileptic parietooccipital regions only in two patients and in the epileptic mesial temporal structures. CONCLUSIONS There is consistent occurrence of physiologic HFOs over vast areas of the neocortex outside the epileptic network. HFOs from nonepileptic regions were seen in the occipital lobes and in the perirolandic region in all patients. Although duration of ripples and peak frequency of HFOs are the most effective measures in distinguishing pathologic from physiologic events, there was significant overlap between the two groups.
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Affiliation(s)
- Rafeed Alkawadri
- Department of Neurology, Yale Comprehensive Epilepsy Center, New Haven, Connecticut, U.S.A
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27
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Kakisaka Y, Jehi L, Alkawadri R, Wang ZI, Enatsu R, Mosher JC, Dubarry AS, Alexopoulos AV, Burgess RC. Cephalic aura after frontal lobe resection. J Clin Neurosci 2014; 21:1450-2. [PMID: 24613491 DOI: 10.1016/j.jocn.2013.11.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 11/10/2013] [Indexed: 10/25/2022]
Abstract
A cephalic aura is a common sensory aura typically seen in frontal lobe epilepsy. The generation mechanism of cephalic aura is not fully understood. It is hypothesized that to generate a cephalic aura extensive cortical areas need to be excited. We report a patient who started to have cephalic aura after right frontal lobe resection. Magnetoencephalography (MEG) showed interictal spike and ictal change during cephalic aura, both of which were distributed in the right frontal region, and the latter involved much more widespread areas than the former on MEG sensors. The peculiar seizure onset pattern may indicate that surgical modification of the epileptic network was related to the appearance of cephalic aura. We hypothesize that generation of cephalic aura may be associated with more extensive cortical involvement of epileptic activity than that of interictal activity, in at least a subset of cases.
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Affiliation(s)
- Yosuke Kakisaka
- Epilepsy Center, Department of Neurology, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA; Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan.
| | - Lara Jehi
- Epilepsy Center, Department of Neurology, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Rafeed Alkawadri
- The Department of Neurology, School of Medicine, Yale University, New Haven, CT, USA
| | - Zhong I Wang
- Epilepsy Center, Department of Neurology, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Rei Enatsu
- Epilepsy Center, Department of Neurology, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - John C Mosher
- Epilepsy Center, Department of Neurology, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Anne-Sophie Dubarry
- Epilepsy Center, Department of Neurology, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Andreas V Alexopoulos
- Epilepsy Center, Department of Neurology, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Richard C Burgess
- Epilepsy Center, Department of Neurology, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Abstract
IMPORTANCE The literature on cingulate gyrus epilepsy in the magnetic resonance imaging era is limited to case reports and small case series. To our knowledge, this is the largest study of surgically confirmed epilepsy arising from the anterior or posterior cingulate region. OBJECTIVE To characterize the clinical and electrophysiological findings of epilepsies arising from the anterior and posterior cingulate gyrus. DESIGN, SETTING, AND PARTICIPANTS We studied consecutive cingulate gyrus epilepsy cases identified retrospectively from the Cleveland Clinic and University of Texas Southwestern Medical Center epilepsy databases from 1992 to 2009. Participants included 14 consecutive cases of cingulate gyrus epilepsies confirmed by restricted magnetic resonance image lesions and seizure freedom or marked improvement following lesionectomy. MAIN OUTCOMES AND MEASURES The main outcome measure was improvement in seizure frequency following surgery. The clinical, video electroencephalography, neuroimaging, pathology, and surgical outcome data were reviewed. RESULTS All 14 patients had cingulate epilepsy confirmed by restricted magnetic resonance image lesions and seizure freedom or marked improvement following lesionectomy. They were divided into 3 groups based on anatomical location of the lesion and corresponding seizure semiology. In the posterior cingulate group, all 4 patients had electroclinical findings suggestive of temporal origin of the epilepsy. The anterior cingulate cases were divided into a typical (Bancaud) group (6 cases with hypermotor seizures and infrequent generalization with the presence of fear, laughter, or severe interictal personality changes) and an atypical group (4 cases presenting with simple motor seizures and a tendency for more frequent generalization and less-favorable long-term surgical outcome). All atypical cases were associated with an underlying infiltrative astrocytoma. CONCLUSIONS AND RELEVANCE Posterior cingulate gyrus epilepsy may present with electroclinical findings that are suggestive of temporal lobe epilepsy and can be considered as another example of pseudotemporal epilepsies. The electroclinical presentation and surgical outcome of lesional anterior cingulate epilepsy is possibly influenced by the underlying pathology. This study highlights the difficulty in localizing seizures arising from the cingulate gyrus in the absence of a magnetic resonance image lesion.
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Gaspard N, Alkawadri R, Farooque P, Goncharova II, Zaveri HP. Automatic detection of prominent interictal spikes in intracranial EEG: validation of an algorithm and relationsip to the seizure onset zone. Clin Neurophysiol 2013; 125:1095-103. [PMID: 24269092 DOI: 10.1016/j.clinph.2013.10.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 10/21/2013] [Accepted: 10/27/2013] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To develop an algorithm for the automatic quantitative description and detection of spikes in the intracranial EEG and quantify the relationship between prominent spikes and the seizure onset zone. METHODS An algorithm was developed for the quantification of time-frequency properties of spikes (upslope, instantaneous energy, downslope) and their statistical representation in a univariate generalized extreme value distribution. Its performance was evaluated in comparison to expert detection of spikes in intracranial EEG recordings from 10 patients. It was subsequently used in 18 patients to detect prominent spikes and quantify their spatial relationship to the seizure onset area. RESULTS The algorithm displayed an average sensitivity of 63.4% with a false detection rate of 3.2 per minute for the detection of individual spikes and an average sensitivity of 88.6% with a false detection rate of 1.4% for the detection of intracranial EEG contacts containing the most prominent spikes. Prominent spikes occurred closer to the seizure onset area than less prominent spikes but they overlapped with it only in a minority of cases (3/18). CONCLUSIONS Automatic detection and quantification of the morphology of spikes increases their utility to localize the seizure onset area. Prominent spikes tend to originate mostly from contacts located in the close vicinity of the seizure onset area rather than from within it. SIGNIFICANCE Quantitative analysis of time-frequency characteristics and spatial distribution of intracranial spikes provides complementary information that may be useful for the localization of the seizure-onset zone.
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Affiliation(s)
- Nicolas Gaspard
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA.
| | - Rafeed Alkawadri
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA
| | - Pue Farooque
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA
| | - Irina I Goncharova
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA
| | - Hitten P Zaveri
- Comprehensive Epilepsy Center and Computational Neurophysiology Laboratory, Dept. of Neurology, School of Medicine, Yale University, Yale-New Haven Hospital, New Haven, CT, USA
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Alkawadri R, Krishnan B, Kakisaka Y, Nair D, Mosher JC, Burgess RC, Alexopoulos AV. Localization of the ictal onset zone with MEG using minimum norm estimate of a narrow band at seizure onset versus standard single current dipole modeling. Clin Neurophysiol 2013; 124:1915-8. [PMID: 23642832 DOI: 10.1016/j.clinph.2013.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 03/12/2013] [Accepted: 03/13/2013] [Indexed: 10/26/2022]
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Alkawadri R, Burgess R, Isitan C, Wang IZ, Kakisaka Y, Alexopoulos AV. Yield of repeat routine MEG recordings in clinical practice. Epilepsy Behav 2013; 27:416-9. [PMID: 23541858 DOI: 10.1016/j.yebeh.2013.02.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 02/18/2013] [Accepted: 02/26/2013] [Indexed: 11/28/2022]
Abstract
From 377 consecutive MEG studies for patients with intractable epilepsy performed at the Cleveland Clinic between 2008 and 2011, 19 patients were referred for a repeat MEG. Source localization was done using a single equivalent current dipole (ECD) model on identified interictal spike activity. Clinical, neuroimaging, and concurrent EEG and MEG findings were reviewed. The most common reasons for repeating MEG were as follows: negative initial study in 6 patients, paucity of recorded interictal discharges in 4, failed surgeries in 3, uncertain findings in the first study in 2, and research-related reasons in 4. Repeat MEG provided new localizing findings in 11/19 patients (58%), of whom 6 had negative or rare interictal findings in the first study. Lobar concordance of dipoles was present in 6 (85%) of the 7 patients with positive findings in both MEG studies. This study demonstrates that a repeat MEG may provide new localization data when a previous recording shows limited or no interictal abnormalities.
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Affiliation(s)
- Rafeed Alkawadri
- Cleveland Clinic Epilepsy Center, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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Awad A, Stüve O, Mayo M, Alkawadri R, Estephan B. Anti-glutamic Acid decarboxylase antibody-associated ataxia as an extrahepatic autoimmune manifestation of hepatitis C infection: a case report. Case Rep Neurol Med 2011; 2011:975152. [PMID: 22937348 PMCID: PMC3420584 DOI: 10.1155/2011/975152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 06/15/2011] [Indexed: 11/18/2022] Open
Abstract
Extrahepatic immunological manifestations of hepatitis C virus (HCV) are well described. In addition, antiglutamic acid decarboxylase (GAD) antibody-associated cerebellar ataxia is well-established entity. However, there have been no reports in the literature of anti-GAD antibody-associated ataxia as an extrahepatic manifestation of HCV infection. We report the case of a young woman with chronic hepatitis C virus and multiple extrahepatic autoimmune diseases including Sjögren syndrome and pernicious anemia who presented with subacute midline cerebellar syndrome and was found to have positive antiglutamic acid decarboxylase (GAD) antibody in the serum and cerebrospinal fluid. An extensive diagnostic workup to rule out neoplastic growths was negative, suggesting the diagnosis of nonparaneoplastic antiglutamic acid decarboxylase antibody-associated cerebellar ataxia as an additional extrahepatic manifestation of hepatitis C virus infection. The patient failed to respond to high-dose steroids and intravenous immunoglobulin. Treatment with the monoclonal antibody rituximab stabilized the disease. We postulate that anti-GAD associated ataxia could be an extrahepatic manifestation of HCV infection.
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Affiliation(s)
- Amer Awad
- Baton Rouge Neurology Associates, Baton Rouge General Medical Center, Baton Rouge, LA, USA
| | - Olaf Stüve
- Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Neurology Section, VA North Texas Health Care Systems, Dallas, TX, USA
| | - Marlyn Mayo
- Department of Internal Medicine-Digestive and Liver Diseases, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Rafeed Alkawadri
- Neurological Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Bachir Estephan
- Department of Neurology, University of Kansas Medical Center, Kansas, KS, USA
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Abstract
BACKGROUND Cingulate gyrus epilepsy is controversial because it may overlap with other frontal lobe epilepsy syndromes. Reported cases are rare in the pre-magnetic resonance imaging literature but are more common thereafter. Information about peri-ictal and ictal behaviors is scarce. OBJECTIVES To characterize epilepsy originating from the cingulate gyrus and to report surgical outcomes. DESIGN Case studies. SETTING Academic research. PATIENTS We report 3 surgically treated cases of cingulate gyrus epilepsy, with seizure-free or almost seizure-free outcomes. The cases were identified from a database of 4201 consecutive epilepsy monitoring unit admissions since October 1998 through September 2008. All 3 cases involved cingulate lesions. MAIN OUTCOME MEASURES Neuroimaging, video electroencephalographic, pathologic, and surgical outcome data were reviewed. RESULTS All 3 patients had lesional left anterocingulate seizures confirmed by magnetic resonance imaging and experienced cessation of seizures after lesionectomy. Two patients had auras (fear and laughter) previously associated with cingulate gyrus epilepsy. All patients had clinical features consistent with frontal lobe epilepsy, including hyperkinetic behavior and ictal vocalization. Two patients had behavioral changes with aggression, personality disorder, and poor judgment; some behavioral episodes lasted for days and were socially devastating. One patient, a commercial pilot, showed behavior as a passenger that resulted in a diversionary landing. The other patient demonstrated behavior that led to his arrest, and he was almost arrested again in the hospital for threatening security officers. Aberrant behaviors in all 3 patients completely resolved after lesionectomy. CONCLUSIONS Lesional cingulate gyrus epilepsy is uncommon. Our 3 confirmed cases included 2 patients with unique and severe behavioral changes that resolved with lesionectomy.
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Affiliation(s)
- Rafeed Alkawadri
- Epilepsy Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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