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Wang SH, Arnulfo G, Nobili L, Myrov V, Ferrari P, Ciuciu P, Palva S, Palva JM. Neuronal synchrony and critical bistability: Mechanistic biomarkers for localizing the epileptogenic network. Epilepsia 2024; 65:2041-2053. [PMID: 38687176 DOI: 10.1111/epi.17996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 04/11/2024] [Accepted: 04/11/2024] [Indexed: 05/02/2024]
Abstract
OBJECTIVE Postsurgical seizure freedom in drug-resistant epilepsy (DRE) patients varies from 30% to 80%, implying that in many cases the current approaches fail to fully map the epileptogenic zone (EZ). We aimed to advance a novel approach to better characterize epileptogenicity and investigate whether the EZ encompasses a broader epileptogenic network (EpiNet) beyond the seizure zone (SZ) that exhibits seizure activity. METHODS We first used computational modeling to test putative complex systems-driven and systems neuroscience-driven mechanistic biomarkers for epileptogenicity. We then used these biomarkers to extract features from resting-state stereoelectroencephalograms recorded from DRE patients and trained supervised classifiers to localize the SZ against gold standard clinical localization. To further explore the prevalence of pathological features in an extended brain network outside of the clinically identified SZ, we also used unsupervised classification. RESULTS Supervised SZ classification trained on individual features achieved accuracies of .6-.7 area under the receiver operating characteristic curve (AUC). Combining all criticality and synchrony features further improved the AUC to .85. Unsupervised classification discovered an EpiNet-like cluster of brain regions, in which 51% of brain regions were outside of the SZ. Brain regions in the EpiNet-like cluster engaged in interareal hypersynchrony and locally exhibited high-amplitude bistability and excessive inhibition, which was strikingly similar to the high seizure risk regime revealed by our computational modeling. SIGNIFICANCE The finding that combining biomarkers improves SZ localization accuracy indicates that the novel mechanistic biomarkers for epileptogenicity employed here yield synergistic information. On the other hand, the discovery of SZ-like brain dynamics outside of the clinically defined SZ provides empirical evidence of an extended pathophysiological EpiNet.
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Affiliation(s)
- Sheng H Wang
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
- Le Commissariat à l'énergie atomique et aux énergies alternatives, NeuroSpin, Université Paris-Saclay, Gif-sur-Yvette, France
- Models and Inference for Neuroimaging Data, Inria, Palaiseau, France
| | - Gabriele Arnulfo
- Department of Informatics, Bioengineering, Robotics, and System Engineering, University of Genoa, Genoa, Italy
| | - Lino Nobili
- Child Neuropsychiatry Unit, Istituto di Ricovero e Cura a Carattere Scientifico Istituto Giannina Gaslini, Member of the European Reference Network EpiCARE, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Children's Sciences, University of Genoa, Genoa, Italy
| | - Vladislav Myrov
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | - Paul Ferrari
- Jack H. Miller Magnetoencephalography Center, Helen DeVos Childrens Hospital, Grand Rapids, Michigan, USA
- Department of Pediatrics and Human Development, Michigan State University, East Lansing, Michigan, USA
| | - Philippe Ciuciu
- Le Commissariat à l'énergie atomique et aux énergies alternatives, NeuroSpin, Université Paris-Saclay, Gif-sur-Yvette, France
- Models and Inference for Neuroimaging Data, Inria, Palaiseau, France
| | - Satu Palva
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- Centre for Cognitive Neuroimaging, School of Psychology and Neuroscience, University of Glasgow, Glasgow, UK
- Division of Psychology, Values, Ideologies and Social Contexts of Education, Faculty of Education and Psychology, University of Oulu, Oulu, Finland
| | - J Matias Palva
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
- Centre for Cognitive Neuroimaging, School of Psychology and Neuroscience, University of Glasgow, Glasgow, UK
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Lai E, Mai X, Ji M, Li S, Meng J. High-Frequency Discrete-Interval Binary Sequence in Asynchronous C-VEP-Based BCI for Visual Fatigue Reduction. IEEE J Biomed Health Inform 2024; 28:2769-2780. [PMID: 38442053 DOI: 10.1109/jbhi.2024.3373332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
In code-modulated visual evoked potential (c-VEP) based BCI systems, flickering visual stimuli may result in visual fatigue. Thus, we introduced a discrete-interval binary sequence (DIBS) as visual stimulus modulation, with its power spectrum optimized to emphasize high-frequency components (40 Hz-60 Hz). 8 and 17 subjects participated, respectively, in offline and online experiments on a 4-target asynchronous c-VEP-based BCI system designed to realize a high positive predictive value (PPV), a low false positive rate (FPR) during idle states, and a high true positive rate (TPR) in control states, while minimizing visual fatigue level. Two visual stimuli modulations were introduced and compared: a maximum length sequence (m-sequence) and the high-frequency discrete-interval binary sequence (DIBS). The decoding algorithm was compared among the canonical correlation analysis (CCA), the task-related component analysis (TRCA), and two approaches of sub-band component weight calculation (the traditional method and the proportional method) for FBCCA and FBTRCA. In the online experiments, the average PPV, FPR and TPR achieved, respectively [Formula: see text], [Formula: see text], [Formula: see text] with m-sequence, while [Formula: see text], [Formula: see text] and [Formula: see text] with DIBS. Estimated by objective eye-related metrics and a subjective questionnaire, the visual fatigue in DIBS cases is significantly smaller than that in m-sequence cases. In this study, the feasibility of a novel modulation approach for visual fatigue reduction was proved in an asynchronous c-VEP system, while maintaining comparable performance to existing methods, which provides further insights towards enhancing this field's long-term viability and user-friendliness.
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Blanpain LT, Cole ER, Chen E, Park JK, Walelign MY, Gross RE, Cabaniss BT, Willie JT, Singer AC. Multisensory flicker modulates widespread brain networks and reduces interictal epileptiform discharges. Nat Commun 2024; 15:3156. [PMID: 38605017 PMCID: PMC11009358 DOI: 10.1038/s41467-024-47263-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 03/26/2024] [Indexed: 04/13/2024] Open
Abstract
Modulating brain oscillations has strong therapeutic potential. Interventions that both non-invasively modulate deep brain structures and are practical for chronic daily home use are desirable for a variety of therapeutic applications. Repetitive audio-visual stimulation, or sensory flicker, is an accessible approach that modulates hippocampus in mice, but its effects in humans are poorly defined. We therefore quantified the neurophysiological effects of flicker with high spatiotemporal resolution in patients with focal epilepsy who underwent intracranial seizure monitoring. In this interventional trial (NCT04188834) with a cross-over design, subjects underwent different frequencies of flicker stimulation in the same recording session with the effect of sensory flicker exposure on local field potential (LFP) power and interictal epileptiform discharges (IEDs) as primary and secondary outcomes, respectively. Flicker focally modulated local field potentials in expected canonical sensory cortices but also in the medial temporal lobe and prefrontal cortex, likely via resonance of stimulated long-range circuits. Moreover, flicker decreased interictal epileptiform discharges, a pathological biomarker of epilepsy and degenerative diseases, most strongly in regions where potentials were flicker-modulated, especially the visual cortex and medial temporal lobe. This trial met the scientific goal and is now closed. Our findings reveal how multi-sensory stimulation may modulate cortical structures to mitigate pathological activity in humans.
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Affiliation(s)
- Lou T Blanpain
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
- Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, USA
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA, USA
| | - Eric R Cole
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA, USA
| | - Emily Chen
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - James K Park
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Michael Y Walelign
- Department of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
- Departments of Neurosurgery and Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick and New Jersey Medical School, Newark, NJ, USA
| | - Brian T Cabaniss
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Jon T Willie
- Departments of Neurological Surgery, Neurology, Psychiatry, and Biomedical Engineering, Washington University, St. Louis, MO, USA.
| | - Annabelle C Singer
- Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, USA.
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA, USA.
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Yılmaz Erol T, Cerrahoğlu Şirin T, Görkem Şirin N, Bebek N, Baykan B. Long-term prognosis of patients with photosensitive idiopathic generalized epilepsy. Seizure 2024; 117:235-243. [PMID: 38520962 DOI: 10.1016/j.seizure.2024.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/25/2024] Open
Abstract
OBJECTIVE The long-term prognosis of photosensitive idiopathic generalized epilepsy (p-IGE) is generally considered favorable; however, its specific characteristics remain unclear. Our objective was to investigate the extended prognosis of p-IGE. METHODS We analyzed the demographics, clinical, and electroencephalographic (EEG) data of consecutive patients who were diagnosed as having p-IGE, who were under follow-up for a minimum of 10 years and exhibited a photoparoxysmal response (PPR) in their EEGs. Prognostic data, epilepsy course types, and electroclinical variables were compared using appropriate statistical methods. RESULTS The mean follow-up duration for 108 consecutive patients with p-IGE (74.1 % female) was 16.8 ± 6.5 years. The main syndromes within this cohort included juvenile myoclonic epilepsy (37 %), juvenile absence epilepsy (15.7 %), and epilepsy with eyelid myoclonia (EEM) (14.8 %). In terms of epilepsy course types, 27.8 % were in the relapse-remission group, and 13.9 % had never experienced remission. A low early remission rate (5.6 %) was evident, with the remaining half of the cohort categorized as the late remission group. Several significant poor prognostic factors were identified including self-induction, clinical symptoms accompanying PPR, asynchrony and focal findings in EEG discharges, a wide frequency range of PPR, the coexistence of three seizure types, the presence of accompanying focal seizure features, and a history of convulsive status epilepticus. CONCLUSIONS Our long-term follow-up study, conducted within a substantial p-IGE group, unveiled newly proposed course types within this epilepsy category and highlighted significant poor prognostic factors related to photosensitivity. These findings furnish valuable insights for precise prognosis counselling and effective management strategies for patients with p-IGE.
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Affiliation(s)
- Tülay Yılmaz Erol
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
| | - Tuba Cerrahoğlu Şirin
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey; Department of Neurology, SBU Sisli Hamidiye Etfal Education and Training Hospital, Istanbul, Turkey.
| | - Nermin Görkem Şirin
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
| | - Nerses Bebek
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
| | - Betül Baykan
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey; Department of Neurology, EMAR Medical Center, Istanbul, Turkey.
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Cohen Z, Steinbrenner M, Piper RJ, Tangwiriyasakul C, Richardson MP, Sharp DJ, Violante IR, Carmichael DW. Transcranial electrical stimulation during functional magnetic resonance imaging in patients with genetic generalized epilepsy: a pilot and feasibility study. Front Neurosci 2024; 18:1354523. [PMID: 38572149 PMCID: PMC10989273 DOI: 10.3389/fnins.2024.1354523] [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: 12/12/2023] [Accepted: 02/13/2024] [Indexed: 04/05/2024] Open
Abstract
Objective A third of patients with epilepsy continue to have seizures despite receiving adequate antiseizure medication. Transcranial direct current stimulation (tDCS) might be a viable adjunct treatment option, having been shown to reduce epileptic seizures in patients with focal epilepsy. Evidence for the use of tDCS in genetic generalized epilepsy (GGE) is scarce. We aimed to establish the feasibility of applying tDCS during fMRI in patients with GGE to study the acute neuromodulatory effects of tDCS, particularly on sensorimotor network activity. Methods Seven healthy controls and three patients with GGE received tDCS with simultaneous fMRI acquisition while watching a movie. Three tDCS conditions were applied: anodal, cathodal and sham. Periods of 60 s without stimulation were applied between each stimulation condition. Changes in sensorimotor cortex connectivity were evaluated by calculating the mean degree centrality across eight nodes of the sensorimotor cortex defined by the Automated Anatomical Labeling atlas (primary motor cortex (precentral left and right), supplementary motor area (left and right), mid-cingulum (left and right), postcentral gyrus (left and right)), across each of the conditions, for each participant. Results Simultaneous tDCS-fMRI was well tolerated in both healthy controls and patients without adverse effects. Anodal and cathodal stimulation reduced mean degree centrality of the sensorimotor network (Friedman's ANOVA with Dunn's multiple comparisons test; adjusted p = 0.02 and p = 0.03 respectively). Mean degree connectivity of the sensorimotor network during the sham condition was not different to the rest condition (adjusted p = 0.94). Conclusion Applying tDCS during fMRI was shown to be feasible and safe in a small group of patients with GGE. Anodal and cathodal stimulation caused a significant reduction in network connectivity of the sensorimotor cortex across participants. This initial research supports the feasibility of using fMRI to guide and understand network modulation by tDCS that might facilitate its clinical application in GGE in the future.
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Affiliation(s)
- Zachary Cohen
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Mirja Steinbrenner
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Rory J. Piper
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- University College London Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Chayanin Tangwiriyasakul
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Mark P. Richardson
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience, King’s College London, London, United Kingdom
| | - David J. Sharp
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Department of Medicine, Imperial College London, London, United Kingdom
| | - Ines R. Violante
- School of Psychology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - David W. Carmichael
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
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Yılmaz Erol T, İlgezdi Kaya İ, Ur Özçelik E, Aksu S, Şirin NG, Bebek N, Kurt A, Karamürsel S, Baykan B. Acute effect of transcranial direct current stimulation on photoparoxysmal response. Epilepsy Res 2024; 201:107320. [PMID: 38412793 DOI: 10.1016/j.eplepsyres.2024.107320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/22/2024] [Accepted: 02/07/2024] [Indexed: 02/29/2024]
Abstract
INTRODUCTION Transcranial direct current stimulation (tDCS) is a non-invasive technique, used to modify the excitability of the central nervous system. The main mechanism of tDCS is to change the excitability by subthreshold modulation by affecting neuronal membrane potentials in the direction of depolarization or repolarization. tDCS was previously investigated as an alternative adjunctive therapy in patients with epilepsy. We aimed here to investigate the acute effect of tDCS on the photoparoxysmal response (PPR) in EEG. METHODS We enrolled 11 consecutive patients diagnosed with idiopathic generalized epilepsy who had PPR on at least 2 EEGs. Three different procedures, including sham, anodal, and cathodal tDCS were applied to the patients at intervals of one week by placing the active electrode over Oz, for 2 mA, 20 minutes. Spike-wave indices (SWI) were counted by two researchers independently and were compared during intermittent photic stimulation (IPS) on EEGs both before and after the application. RESULTS After cathodal tDCS, SWI increased compared to baseline EEG and sham EEG in 3 patients, and after anodal tDCS, SWI increased in 2 patients. Although the SWI values did not change significantly, 8 patients reported subjectively that the applications were beneficial for them and that they experienced less discomfort during photic stimulation after the sessions. There were no side effects except transient skin rash in one patient, only. CONCLUSIONS In our sham controlled tDCS study with both cathodal and anodal stimulation, our data showed that there was no significant change in SWI during IPS, despite subjective well-being. tDCS' modulatory effect does not seem to act in the acute phase on EEG parameters after photic stimulation.
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Affiliation(s)
- Tülay Yılmaz Erol
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
| | - İrem İlgezdi Kaya
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
| | - Emel Ur Özçelik
- Department of Neurology, University of Health Sciences, Kanuni Sultan Süleyman Education and Research Hospital, Istanbul, Turkey.
| | - Serkan Aksu
- Department of Physiology, Faculty of Medicine, Muğla Sıtkı Koçman University, Muğla, Turkey.
| | - Nermin Görkem Şirin
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
| | - Nerses Bebek
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
| | - Adnan Kurt
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey.
| | - Sacit Karamürsel
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey.
| | - Betül Baykan
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey; Department of Neurology, EMAR Medical Center, Istanbul, Turkey.
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Kelly A, Dunne J, Orr C, Lawn N. Adult-onset Kufs disease. Pract Neurol 2024; 24:41-44. [PMID: 37802651 DOI: 10.1136/pn-2022-003652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2023] [Indexed: 10/08/2023]
Abstract
A young man from Pakistan had his first-ever tonic-clonic seizure while playing cricket. Since age 12 years, he had reported involuntary jerks and tremulousness, sometimes with falls, particularly with bright lights. Family history included a brother who developed seizures with myoclonus in his mid-20s and parental consanguinity. Developmental history was normal. Examination identified cognitive impairment with action myoclonus. His clinical presentation raised suspicion of a progressive myoclonus epilepsy. MR scan of the brain showed white matter changes suggesting leucodystrophy with cortical atrophy. Electroencephalogram showed generalised epileptiform abnormalities with photoparoxysmal responses, including at low frequencies (1 Hz). Cortical hyperexcitability was confirmed with giant median somatosensory evoked potentials and long loop reflexes at rest. Multichannel electromyography showed action myoclonus with variable synchronous and asynchronous agonist and antagonist muscle activation with short-burst duration of 25-75 ms, and jerk-locked back-averaging showed premyoclonic potentials consistent with cortical myoclonus. Genetic sequencing identified a homozygous missense variant in the CLN6 gene (c.768C>G p.(Asp256Glu), confirming Kufs disease type A.
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Affiliation(s)
- Albert Kelly
- Neurology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - John Dunne
- Neurology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- Internal Medicine, The University of Western Australia Faculty of Health and Medical Sciences, Perth, Western Australia, Australia
| | - Carolyn Orr
- Neurology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Nicholas Lawn
- Neurology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- Neurology, Western Australian Adult Epilepsy Service, Perth, Western Australia, Australia
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Zawar I, Shreshtha B, Benech D, Burgess RC, Bulacio J, Knight EMP. Electrographic Features of Epilepsy With Eyelid Myoclonia With Photoparoxysmal Responses. J Clin Neurophysiol 2024; 41:83-92. [PMID: 35394968 DOI: 10.1097/wnp.0000000000000942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Epilepsy with eyelid myoclonia (EMA) is characterized by eyelid myoclonia, eyelid closure sensitivity, and photosensitivity. EEG may manifest with frontal-predominant (FPEDs) or occipital-predominant epileptiform discharges (OPEDs). Data on clinical and electrographic features of these two subtypes are lacking. The purpose of our research was to look at baseline electroclinical features of EMA subtypes and to study electrographic findings of patients with EMA during intermittent photic stimulation (IPS). METHODS We retrospectively identified all patients who had photoparoxysmal responses on EEGs performed at Cleveland clinic between January 01, 2012, and December 31, 2019. Patients who met diagnostic criteria for EMA were studied further. RESULTS Of the 249 patients with photoparoxysmal responses, 70 (28.1%) had EMA (62 [88.6%] female; the mean age of epilepsy onset: 7.0 ± 7.9 years). Patients with EMA had either FPEDs or OPEDs. Eleven patients with EMA (15.7%) had seizures (4 absence, 5 myoclonic and 2 bilateral tonic-clonic) during IPS. Patients with OPEDs were more likely to have drug-resistant epilepsy; occipital focal IEDs and other focal IEDs (other than frontal/occipital) on baseline EEG; and generalized IEDs with occipital predominance, generalized IEDs with no predominance, or focal IEDs during IPS. Predictors of seizure occurrence during photic stimulation included the presence of focal occipital IEDs on baseline EEG, generalized IEDs with frontal predominance during IPS, and photoparoxysmal response outlasting the stimulus. CONCLUSIONS Our study provides evidence that EMA has two distinct subtypes, which differ in clinical characteristics, baseline EEG, and EEG during photic stimulation. We highlight diagnostic and prognostic implications of these findings. Our study also details EEG characteristics of patients with EMA during IPS.
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Affiliation(s)
- Ifrah Zawar
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A.; and
- Department of Neurology, University of Virginia School of Medicine, Virginia, U.S.A
| | - Bijina Shreshtha
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A.; and
| | - Daniela Benech
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A.; and
| | - Richard C Burgess
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A.; and
| | - Juan Bulacio
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A.; and
| | - Elia M Pestana Knight
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A.; and
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Niu Y, Gong P, Jiao X, Xu Z, Zhou Z, Zhang Y, Qin J, Yang Z. Electroclinical Features and Long-Term Photosensitivity Outcome in Patients With Photoparoxysmal Response With Epilepsy. Pediatr Neurol 2023; 147:88-94. [PMID: 37598572 DOI: 10.1016/j.pediatrneurol.2023.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/14/2023] [Accepted: 07/18/2023] [Indexed: 08/22/2023]
Abstract
BACKGROUND To investigate electroclinical phenotypes and long-term photosensitivity outcome in a large pediatric cohort of patients with epilepsy with photosensitivity. METHODS Patients with epilepsy with photosensitivity with four or more years of follow-up were included. Sustained terminal remission (STR) of photosensitivity (≥3.5 years) and seizure control were investigated, as well as the prognostic factors of photosensitivity. Furthermore, a cluster analysis was used to study the different subgroups of photoparoxysmal responses (PPR). RESULTS We included 190 individuals with a median age at diagnosis of photosensitivity of 93.1 months (interquartile range [IQR] 62.8 to 120 months) and a median follow-up duration of 68.5 months (IQR 51.8 to 84 months). STR of photosensitivity was achieved in 97 (51.1%) patients, and the mean time from age at diagnosis of photosensitivity onset to STR was 16.5 months. Age at the last follow-up (9 to 18 years [P = 0.001]), a history of photoconvulsive response (PCR) (P = 0.009), and posterior epileptiform discharges (EDs) of PPRs (P = 0.05) were significantly associated with a lower chance of entering STR according to a Cox proportional hazards model. The subgroup of generalized epilepsy syndrome exhibited 46.2% of eye closure sensitivity and 47.7% of PCR. The rates of focal epilepsy syndrome (cluster 1), generalized epilepsy syndrome (cluster 2), and unclassified epilepsy (cluster 3) were similar and not statistically different in photosensitive outcome (P = 0.527). CONCLUSIONS Age nine to 18 years, a history of PCR, and posterior EDs of PPRs were the adverse factors affecting photosensitivity, suggesting the effect of age-related brain changes in STR. There was no difference in the prognosis of photosensitivity in different epileptic syndromes.
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Affiliation(s)
- Yue Niu
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
| | - Pan Gong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xianru Jiao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhao Xu
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
| | - Zongpu Zhou
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jiong Qin
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University People's Hospital, Beijing, China.
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Tsoneva T, Garcia-Molina G, Desain P. Electrophysiological model of human temporal contrast sensitivity based on SSVEP. Front Neurosci 2023; 17:1180829. [PMID: 37599998 PMCID: PMC10433170 DOI: 10.3389/fnins.2023.1180829] [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: 03/06/2023] [Accepted: 06/27/2023] [Indexed: 08/22/2023] Open
Abstract
The present study aims to connect the psychophysical research on the human visual perception of flicker with the neurophysiological research on steady-state visual evoked potentials (SSVEPs) in the context of their application needs and current technological developments. In four experiments, we investigated whether a temporal contrast sensitivity model could be established based on the electrophysiological responses to repetitive visual stimulation and, if so, how this model compares to the psychophysical models of flicker visibility. We used data from 62 observers viewing periodic flicker at a range of frequencies and modulation depths sampled around the perceptual visibility thresholds. The resulting temporal contrast sensitivity curve (TCSC) was similar in shape to its psychophysical counterpart, confirming that the human visual system is most sensitive to repetitive visual stimulation at frequencies between 10 and 20 Hz. The electrophysiological TCSC, however, was below the psychophysical TCSC measured in our experiments for lower frequencies (1-50 Hz), crossed it when the frequency was 50 Hz, and stayed above while decreasing at a slower rate for frequencies in the gamma range (40-60 Hz). This finding provides evidence that SSVEPs could be measured even without the conscious perception of flicker, particularly at frequencies above 50 Hz. The cortical and perceptual mechanisms that apply at higher temporal frequencies, however, do not seem to directly translate to lower frequencies. The presence of harmonics, which show better response for many frequencies, suggests non-linear processing in the visual system. These findings are important for the potential applications of SSVEPs in studying, assisting, or augmenting human cognitive and sensorimotor functions.
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Affiliation(s)
- Tsvetomira Tsoneva
- Department of Digital Engagement, Cognition and Behavior, Philips Research, Eindhoven, Netherlands
- Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Gary Garcia-Molina
- Sleep Number Labs, San Jose, CA, United States
- Center for Sleep and Consciousness, University of Wisconsin, Madison, WI, United States
| | - Peter Desain
- Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
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11
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Bichromatic visual stimulus with subharmonic response to achieve a high-accuracy SSVEP BCI system with low eye irritation. Biomed Signal Process Control 2023. [DOI: 10.1016/j.bspc.2023.104629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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12
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Takebayashi Y, Neshige S, Shishido T, Hayashi Y, Segawa A, Nakamori M, Nezu T, Aoki S, Yamazaki Y, Ueno H, Ohshita T, Iida K, Maruyama H. Paradoxical effects of levetiracetam in people with epilepsy with rhythmic epileptiform discharges. Epilepsy Behav 2023; 143:109225. [PMID: 37130461 DOI: 10.1016/j.yebeh.2023.109225] [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: 01/23/2023] [Revised: 04/10/2023] [Accepted: 04/12/2023] [Indexed: 05/04/2023]
Abstract
OBJECTIVE To elucidate the incidence and risk factors for paradoxical effects (i.e., increased seizure frequency, increased seizure severity, or onset of new seizure types) of levetiracetam (LEV) in people with epilepsy (PWE) and identify the usefulness of electroencephalography (EEG) in predicting these effects. METHODS We examined data for consecutive PWE treated with LEV. All PWE underwent EEG and magnetic resonance imaging (MRI) before LEV administration. We also evaluated the incidence of paradoxical LEV effects and conducted multivariate logistic regression analyses to identify the associated factors. RESULTS In total, 210 (66.2%) of 317 PWEs treated in our department had a history of LEV use. The incidence of paradoxical LEV effects was 5.2% (n = 11) and was significantly associated with a high LEV dose (p = 0.029), high seizure frequency (p = 0.005), temporal lobe epilepsy (p = 0.004), focal awareness seizure (p = 0.004), focal impaired awareness seizure (p = 0.007), spike (p = 0.015), rhythmic epileptiform discharges (REDs; p = 0.003), and MRI-identified focal cortical dysplasia (FCD; p < 0.0001). Multivariate analyses revealed that REDs (odds ratio [OR] = 5.35, p = 0.048, 95% confidence interval [CI]: 1.01-28.21) were independently associated with paradoxical LEV effects. CONCLUSIONS Paradoxical LEV effects occurred in PWE, particularly in those with drug-resistant focal epilepsy. Furthermore, the occurrence of REDs in EEG was an independent factor associated with the paradoxical effects of LEV in PWE.
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Affiliation(s)
- Yoshiko Takebayashi
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Shuichiro Neshige
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan; Epilepsy Center, Hiroshima University Hospital, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan.
| | - Takeo Shishido
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Yuki Hayashi
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Akiko Segawa
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Masahiro Nakamori
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Tomohisa Nezu
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Shiro Aoki
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Yu Yamazaki
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Hiroki Ueno
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Tomohiko Ohshita
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Koji Iida
- Epilepsy Center, Hiroshima University Hospital, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan; Department of Neurosurgery, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
| | - Hirofumi Maruyama
- Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan; Epilepsy Center, Hiroshima University Hospital, 1-2-3 Kasumi, Minamiku, Hiroshima 734-8551, Japan
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Blanpain LT, Chen E, Park J, Walelign MY, Gross RE, Cabaniss BT, Willie JT, Singer AC. Multisensory Flicker Modulates Widespread Brain Networks and Reduces Interictal Epileptiform Discharges in Humans. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.03.14.23286691. [PMID: 36993248 PMCID: PMC10055448 DOI: 10.1101/2023.03.14.23286691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Modulating brain oscillations has strong therapeutic potential. However, commonly used non-invasive interventions such as transcranial magnetic or direct current stimulation have limited effects on deeper cortical structures like the medial temporal lobe. Repetitive audio-visual stimulation, or sensory flicker, modulates such structures in mice but little is known about its effects in humans. Using high spatiotemporal resolution, we mapped and quantified the neurophysiological effects of sensory flicker in human subjects undergoing presurgical intracranial seizure monitoring. We found that flicker modulates both local field potential and single neurons in higher cognitive regions, including the medial temporal lobe and prefrontal cortex, and that local field potential modulation is likely mediated via resonance of involved circuits. We then assessed how flicker affects pathological neural activity, specifically interictal epileptiform discharges, a biomarker of epilepsy also implicated in Alzheimer's and other diseases. In our patient population with focal seizure onsets, sensory flicker decreased the rate interictal epileptiform discharges. Our findings support the use of sensory flicker to modulate deeper cortical structures and mitigate pathological activity in humans.
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Affiliation(s)
- Lou T. Blanpain
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
- Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, USA
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA, USA
| | - Emily. Chen
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - James Park
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Michael Y. Walelign
- Department of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Robert E. Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Brian T. Cabaniss
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Jon T. Willie
- Department of Neurosurgery, Washington University, St. Louis, MO, USA
| | - Annabelle C. Singer
- Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, USA
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA, USA
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Latimer D, Le D, Falgoust E, Ingraffia P, Abd-Elsayed A, Cornett EM, Singh R, Choi J, Varrassi G, Kaye AM, Kaye AD, Ganti L. Brivaracetam to Treat Partial Onset Seizures in Adults. Health Psychol Res 2023; 10:56782. [PMID: 36726475 PMCID: PMC9886169 DOI: 10.52965/001c.56782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Purpose of Review Seizures are a hyperexcitable, and hypersynchronous imbalance between excitatory and inhibitory factors (E/I imbalance) in neurotransmission, and epilepsy is the recurrent manifestation of seizures within a reasonable time frame and without being attributable to a reversible cause. Brivaracetam is a derivative of the antiepileptic agent, levetiracetam, that is used as adjuvant therapy for focal onset seizures. It was approved by the FDA in 2016 and has shown promising results with minimal adverse effect reactions in clinical trials. Recent Findings Brivaracetam has been used in multiple clinical trials at various dosages in adults that have partial-onset seizures refractory to conventional treatment. A meta-analysis in 2016 showed that brivaracetam as adjunctive therapy was statically significant in its reduction of adults with drug-refractory seizure frequency.1 The most commonly reported adverse effects that patients who were taking brivaracetam experienced were somnolence, headache, and dizziness. Further studies are necessary to conclude long term efficacy and safety profile of brivaracetam. Conclusion The treatment of epilepsy with pharmacologic agents is a difficult task due to balancing the efficacy of the drug with the side effect profile that will allow for the best quality of life for the patient. There are approximately 30 antiepileptic agents for clinicians to choose from. Brivaracetam is a novel antiepileptic agent that was approved for use by the FDA in 2016 and is showing promising results as monotherapy and adjunctive therapy in individuals with drug-refractory focal seizures while minimizing adverse drug reactions.
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Affiliation(s)
- Dustin Latimer
- Department of Psychiatry and Behavioral MedicineLouisiana State University Health Science Center, Baton Rouge, LA
| | - David Le
- Louisiana State University New Orleans School of Medicine, New Orleans, LA
| | - Evan Falgoust
- Louisiana State University Shreveport School of Medicine, Shreveport, LA
| | - Patrick Ingraffia
- Louisiana State University Shreveport School of Medicine, Shreveport, LA
| | - Alaa Abd-Elsayed
- Department of AnesthesiologyUniversity of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Elyse M. Cornett
- Department of AnesthesiologyLouisiana State University Shreveport, Shreveport, LA
| | - Rupin Singh
- University of Central Florida College of Medicine, Orlando, FL and HCA Osceola Hospital, Kissimmee, FL
| | - JooHee Choi
- Georgetown University School of Medicine, Washington, DC
| | | | - Adam M. Kaye
- Pharmacy PracticeThomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA
| | - Alan D. Kaye
- Department of AnesthesiologyLouisiana State University Shreveport, Shreveport, LA
| | - Latha Ganti
- University of Central Florida College of Medicine, Orlando, FL and HCA Osceola Hospital, Kissimmee, FL
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Zhang B, Chen T, Hao X, Xin M, Liang J. Electroclinical characteristics of photosensitive epilepsy: A retrospective study of 31 Chinese children and literature review. Front Pediatr 2023; 11:994817. [PMID: 36969295 PMCID: PMC10034115 DOI: 10.3389/fped.2023.994817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/27/2023] [Indexed: 03/29/2023] Open
Abstract
Objective The objective of this study was to better understand the clinical features of photosensitive epilepsy (PSE) in Chinese children. Methods Thirty-one children with PSE were screened out of 398 children with epilepsy who were consecutively diagnosed by the video-electroencephalogram (VEEG) monitoring method and by using an intermittent photic stimulation (IPS) test. Their EEGs and clinical features were retrospectively analyzed, and their treatment outcomes were followed up. Results PSE accounted for 7.79% (31/398) of children with epilepsy during the observation period in our single epilepsy center. The male to female ratio of PSE was 1:3.43, and the average seizure onset age was 7.8 ± 3.28 years. The highest range of frequency sensitivity of the IPS test for the induction of EEG epileptic discharge or electroclinical seizures was within 10-20 Hz. Electroclinical seizures were induced in 41.94% (13/31) of PSE patients by using the IPS test, while EEG discharge without clinical seizures was induced in 58.06% (18/31) of PSE patients. Among all PSE patients, an IPS-positive reaction in the eye-closure state was induced in 83.87% of patients, and this rate was significantly higher than that in the eye-opened state (41.94%) or eye-closed state (35.48%). (Eye-closure IPS stimulation means: make the subjects close their eyes at the beginning of each stimulation, open their eyes at the end of the stimulation, and close their eyes again at the beginning of the next stimulation, and so on. While Eye-closed IPS stimulation means the stimulation is started after 5 s of eye closure, and the subjects are kept closed throughout the whole process.) The common and effective drugs used for single or combined therapy in PSE children were valproic acid and levetiracetam. Conclusion This study provides some useful information about electroclinical characteristics in a cohort of 31 PSE children. It may be beneficial for pediatric neurologists in terms of paying more attention to PSE and correctly dealing with it.
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Affiliation(s)
- Bo Zhang
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
| | - Tianyu Chen
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Department of Pediatrics, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, China
| | - Xiaosheng Hao
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
| | - Meiying Xin
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
| | - Jianmin Liang
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
- Correspondence: Jianmin Liang
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South L, Borkin MA. Photosensitive Accessibility for Interactive Data Visualizations. IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2023; 29:374-384. [PMID: 36166540 DOI: 10.1109/tvcg.2022.3209359] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Accessibility guidelines place restrictions on the use of animations and interactivity on webpages to lessen the likelihood of webpages inadvertently producing sequences with flashes, patterns, or color changes that may trigger seizures for individuals with photosensitive epilepsy. Online data visualizations often incorporate elements of animation and interactivity to create a narrative, engage users, or encourage exploration. These design guidelines have been empirically validated by perceptual studies in visualization literature, but the impact of animation and interaction in visualizations on users with photosensitivity, who may experience seizures in response to certain visual stimuli, has not been considered. We systematically gathered and tested 1,132 interactive and animated visualizations for seizure-inducing risk using established methods and found that currently available methods for determining photosensitive risk are not reliable when evaluating interactive visualizations, as risk scores varied significantly based on the individual interacting with the visualization. To address this issue, we introduce a theoretical model defining the degree of control visualization designers have over three determinants of photosensitive risk in potentially seizure-inducing sequences: the size, frequency, and color of flashing content. Using an analysis of 375 visualizations hosted on bl.ocks.org, we created a theoretical model of photosensitive risk in visualizations by arranging the photosensitive risk determinants according to the degree of control visualization authors have over whether content exceeds photosensitive accessibility thresholds. We then use this model to propose a new method of testing for photosensitive risk that focuses on elements of visualizations that are subject to greater authorial control - and are therefore more robust to variations in the individual user - producing more reliable risk assessments than existing methods when applied to interactive visualizations. A full copy of this paper and all study materials are available at https://osf.io/8kzmg/.
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17
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Sato A, Nakatani S. Independent bilateral-eye stimulation for gaze pattern recognition based on steady-state pupil light reflex. J Neural Eng 2022; 19. [PMID: 36583387 DOI: 10.1088/1741-2552/acab31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 12/13/2022] [Indexed: 12/15/2022]
Abstract
Objective:recently, pupil oscillations synchronized with steady visual stimuli were used as input for an interface. The proposed system, inspired by a brain-computer interface based on steady-state visual evoked potentials, does not require contact with the participant. However, the pupil oscillation mechanism limits the stimulus frequency to 2.5 Hz or less, making it hard to enhance the information transfer rate (ITR).Approach:here, we compared multiple conditions for stimulation to increase the ITR of the pupil vibration-based interface, which were called monocular-single, monocular-superposed, and binocular-independent conditions. The binocular-independent condition stimulates each eye at different frequencies respectively and mixes them by using the visual stereoscopic perception of users. The monocular-superposed condition stimulates both eyes by a mixed signal of two different frequencies. We selected the shape of the stimulation signal, evaluated the amount of spectral leakage in the monocular-superposed and binocular-independent conditions, and compared the power spectrum density at the stimulation frequency. Moreover, 5, 10, and 15 patterns of stimuli were classified in each condition.Main results:a square wave, which causes an efficient pupil response, was used as the stimulus. Spectral leakage at the beat frequency was higher in the monocular-superposed condition than in the binocular-independent one. The power spectral density of stimulus frequencies was greatest in the monocular-single condition. Finally, we could classify the 15-stimulus pattern, with ITRs of 14.4 (binocular-independent, using five frequencies), 14.5 (monocular-superimposed, using five frequencies), and 23.7 bits min-1(monocular-single, using 15 frequencies). There were no significant differences for the binocular-independent and monocular-superposed conditions.Significance:this paper shows a way to increase the number of stimuli that can be simultaneously displayed without decreasing ITR, even when only a small number of frequencies are available. This could lead to the provision of an interface based on pupil oscillation to a wider range of users.
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Affiliation(s)
- Ariki Sato
- Graduate School of Sustainability Science, Tottori University, Tottori, Japan
| | - Shintaro Nakatani
- Graduate School of Sustainability Science, Tottori University, Tottori, Japan.,Faculty of Engineering, Tottori University, Advanced Mechanical and Electronic System Research Center, Tottori University, Tottori, Japan
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Rawat V, Eastman CL, Amaradhi R, Banik A, Fender JS, Dingledine RJ, D’Ambrosio R, Ganesh T. Temporal Expression of Neuroinflammatory and Oxidative Stress Markers and Prostaglandin E2 Receptor EP2 Antagonist Effect in a Rat Model of Epileptogenesis. ACS Pharmacol Transl Sci 2022; 6:128-138. [PMID: 36654746 PMCID: PMC9841781 DOI: 10.1021/acsptsci.2c00189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Indexed: 12/13/2022]
Abstract
Traumatic brain injury (TBI) in patients results in a massive inflammatory reaction, disruption of blood-brain barrier, and oxidative stress in the brain, and these inciting features may culminate in the emergence of post-traumatic epilepsy (PTE). We hypothesize that targeting these pathways with pharmacological agents could be an effective therapeutic strategy to prevent epileptogenesis. To design therapeutic strategies targeting neuroinflammation and oxidative stress, we utilized a fluid percussion injury (FPI) rat model to study the temporal expression of neuroinflammatory and oxidative stress markers from 3 to 24 h following FPI. FPI results in increased mRNA expression of inflammatory mediators including cyclooxygenase-2 (COX-2) and prostanoid receptor EP2, marker of oxidative stress (NOX2), astrogliosis (GFAP), and microgliosis (CD11b) in ipsilateral cortex and hippocampus. The analysis of protein levels indicated a significant increase in the expression of COX-2 in ipsilateral hippocampus and cortex post-FPI. We tested FPI rats with an EP2 antagonist TG8-260 which produced a statistically significant reduction in the distribution of seizure duration post-FPI and trends toward a reduction in seizure incidence, seizure frequency, and duration, hinting a proof of concept that EP2 antagonism must be further optimized for therapeutic applications to prevent epileptogenesis.
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Affiliation(s)
- Varun Rawat
- Department
of Pharmacology and Chemical Biology, Emory
University School of Medicine, Atlanta, Georgia 30322, United States
| | - Clifford L. Eastman
- Department
of Neurological Surgery, University of Washington, 325 Ninth Avenue, Seattle, Washington 98104, United States
| | - Radhika Amaradhi
- Department
of Pharmacology and Chemical Biology, Emory
University School of Medicine, Atlanta, Georgia 30322, United States
| | - Avijit Banik
- Department
of Pharmacology and Chemical Biology, Emory
University School of Medicine, Atlanta, Georgia 30322, United States
| | - Jason S. Fender
- Department
of Neurological Surgery, University of Washington, 325 Ninth Avenue, Seattle, Washington 98104, United States
| | - Raymond J. Dingledine
- Department
of Pharmacology and Chemical Biology, Emory
University School of Medicine, Atlanta, Georgia 30322, United States
| | - Raimondo D’Ambrosio
- Department
of Neurological Surgery, University of Washington, 325 Ninth Avenue, Seattle, Washington 98104, United States,Regional
Epilepsy Center, University of Washington, 325 Ninth Avenue, Seattle, Washington 98104, United States
| | - Thota Ganesh
- Department
of Pharmacology and Chemical Biology, Emory
University School of Medicine, Atlanta, Georgia 30322, United States,. Phone: 404-727-7393. Fax: 404-727-0365
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Brickwedde M, Bezsudnova Y, Kowalczyk A, Jensen O, Zhigalov A. Application of rapid invisible frequency tagging for brain computer interfaces. J Neurosci Methods 2022; 382:109726. [PMID: 36228894 PMCID: PMC7615063 DOI: 10.1016/j.jneumeth.2022.109726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 09/20/2022] [Accepted: 10/08/2022] [Indexed: 11/07/2022]
Abstract
BACKGROUND Brain-computer interfaces (BCI) based on steady-state visual evoked potentials (SSVEPs/SSVEFs) are among the most commonly used BCI systems. They require participants to covertly attend to visual objects flickering at specified frequencies. The attended location is decoded online by analysing the power of neuronal responses at the flicker frequency. NEW METHOD We implemented a novel rapid invisible frequency-tagging technique, utilizing a state-of-the-art projector with refresh rates of up to 1440 Hz. We flickered the luminance of visual objects at 56 and 60 Hz, which was invisible to participants but produced strong neuronal responses measurable with magnetoencephalography (MEG). The direction of covert attention, decoded from frequency-tagging responses, was used to control an online BCI PONG game. RESULTS Our results show that seven out of eight participants were able to play the pong game controlled by the frequency-tagging signal, with average accuracies exceeding 60 %. Importantly, participants were able to modulate the power of the frequency-tagging response within a 1-second interval, while only seven occipital sensors were required to reliably decode the neuronal response. COMPARISON WITH EXISTING METHODS In contrast to existing SSVEP-based BCI systems, rapid frequency-tagging does not produce a visible flicker. This extends the time-period participants can use it without fatigue, by avoiding distracting visual input. Furthermore, higher frequencies increase the temporal resolution of decoding, resulting in higher communication rates. CONCLUSION Using rapid invisible frequency-tagging opens new avenues for fundamental research and practical applications. In combination with novel optically pumped magnetometers (OPMs), it could facilitate the development of high-speed and mobile next-generation BCI systems.
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Affiliation(s)
- Marion Brickwedde
- Centre for Human Brain Health, University of Birmingham, United Kingdom; Charité, Department of Child and Adolescent Psychiatry, Charité-Universitätsmedizin, Berlin, Germany.
| | - Yulia Bezsudnova
- Centre for Human Brain Health, University of Birmingham, United Kingdom.
| | - Anna Kowalczyk
- Centre for Human Brain Health, University of Birmingham, United Kingdom.
| | - Ole Jensen
- Centre for Human Brain Health, University of Birmingham, United Kingdom.
| | - Alexander Zhigalov
- Centre for Human Brain Health, University of Birmingham, United Kingdom; Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, United Kingdom.
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Mussi MG, Adams KD. EEG hybrid brain-computer interfaces: A scoping review applying an existing hybrid-BCI taxonomy and considerations for pediatric applications. Front Hum Neurosci 2022; 16:1007136. [DOI: 10.3389/fnhum.2022.1007136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 10/27/2022] [Indexed: 11/18/2022] Open
Abstract
Most hybrid brain-computer interfaces (hBCI) aim at improving the performance of single-input BCI. Many combinations are possible to configure an hBCI, such as using multiple brain input signals, different stimuli or more than one input system. Multiple studies have been done since 2010 where such interfaces have been tested and analyzed. Results and conclusions are promising but little has been discussed as to what is the best approach for the pediatric population, should they use hBCI as an assistive technology. Children might face greater challenges when using BCI and might benefit from less complex interfaces. Hence, in this scoping review we included 42 papers that developed hBCI systems for the purpose of control of assistive devices or communication software, and we analyzed them through the lenses of potential use in clinical settings and for children. We extracted taxonomic categories proposed in previous studies to describe the types of interfaces that have been developed. We also proposed interface characteristics that could be observed in different hBCI, such as type of target, number of targets and number of steps before selection. Then, we discussed how each of the extracted characteristics could influence the overall complexity of the system and what might be the best options for applications for children. Effectiveness and efficiency were also collected and included in the analysis. We concluded that the least complex hBCI interfaces might involve having a brain inputs and an external input, with a sequential role of operation, and visual stimuli. Those interfaces might also use a minimal number of targets of the strobic type, with one or two steps before the final selection. We hope this review can be used as a guideline for future hBCI developments and as an incentive to the design of interfaces that can also serve children who have motor impairments.
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21
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Aboutabl ME, Elkhateeb WA, Masoud MA, Daba GM, Afifi AH, Hussein RA. HPLC and GC-MS based metabolic profiles and in vivo anticonvulsant, sedative, and antinociceptive potentials of truffles Tirmania nivea and Tirmania pinoyi hydromethanolic extracts in mice. Biomed Chromatogr 2022; 36:e5481. [PMID: 35971328 DOI: 10.1002/bmc.5481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 11/12/2022]
Abstract
GC-MS and HPLC analyses of the hydromethanolic extracts of the truffles Tirmania nivea (TN) and Tirmania pinoyi (TP) revealed the presence of 18 metabolites and 11 polyphenols, respectively. In vivo, TP extract protected against subcutaneous pentylenetetrazole (scPTZ) and maximal electric shock (MES)-induced convulsions faster than TN. TP (100 and 300 mg/kg) showed 100% protection and longer duration than TN in the scPTZ test. Similarly, at 300 mg/kg, TP demonstrated a quicker start (75%) and longer duration of action (100%) than TN in MES test. In scPTZ test, ED50 of TP demonstrated greater anticonvulsant efficacy than TN. In mice given TP and TN treatments, the brain GABA levels were noticeably increased. TP (100 and 300mg/kg) produced a notable sedative effect in open field test, whereas TN (100 or 300 mg/kg) and TP (300 mg/kg) reduced sleep latency by 79, 52, and 45%, respectively. In writhing test, TN (100 or 300mg/kg) significantly enhanced analgesic efficacy by 50 and 87%, respectively. Comparatively, in formalin test, TP and TN at a dosage of 300 mg/kg decreased the length of the licking by 34 and 59%, respectively. For the first time, this study explains the anticonvulsant, sedative, central, and peripheral analgesic activities of truffle extracts.
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Affiliation(s)
- Mona E Aboutabl
- Medicinal and Pharmaceutical Chemistry Department (Pharmacology Group), Pharmaceutical and Drug Industries Research Institute, National Research Centre (ID: 60014618), Giza, Egypt
| | - Waill A Elkhateeb
- Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre (ID: 60014618), Giza, Egypt
| | - Marwa A Masoud
- Pharmacology Department, National Organization for Drug Control and Research, Egyptian Drug Authority (EDA), Giza, Egypt
| | - Ghoson M Daba
- Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre (ID: 60014618), Giza, Egypt
| | - Ahmed H Afifi
- Pharmacognosy Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre (ID: 60014618), Giza, Egypt
| | - Rehab A Hussein
- Pharmacognosy Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre (ID: 60014618), Giza, Egypt
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22
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Mak J, Kocanaogullari D, Huang X, Kersey J, Shih M, Grattan ES, Skidmore ER, Wittenberg GF, Ostadabbas S, Akcakaya M. Detection of Stroke-Induced Visual Neglect and Target Response Prediction Using Augmented Reality and Electroencephalography. IEEE Trans Neural Syst Rehabil Eng 2022; 30:1840-1850. [PMID: 35786558 DOI: 10.1109/tnsre.2022.3188184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We aim to build a system incorporating electroencephalography (EEG) and augmented reality (AR) that is capable of identifying the presence of visual spatial neglect (SN) and mapping the estimated neglected visual field. An EEG-based brain-computer interface (BCI) was used to identify those spatiospectral features that best detect participants with SN among stroke survivors using their EEG responses to ipsilesional and contralesional visual stimuli. Frontal-central delta and alpha, frontal-parietal theta, Fp1 beta, and left frontal gamma were found to be important features for neglect detection. Additionally, temporal analysis of the responses shows that the proposed model is accurate in detecting potentially neglected targets. These targets were predicted using common spatial patterns as the feature extraction algorithm and regularized discriminant analysis combined with kernel density estimation for classification. With our preliminary results, our system shows promise for reliably detecting the presence of SN and predicting visual target responses in stroke patients with SN.
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23
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Strzelecka J, Mazurkiewicz DW, Skadorwa T, Gąsior JS, Jóźwiak S. Photo-Dependent Reflex Seizures—A Scoping Review with Proposal of Classification. J Clin Med 2022; 11:jcm11133766. [PMID: 35807051 PMCID: PMC9267825 DOI: 10.3390/jcm11133766] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/10/2022] [Accepted: 06/28/2022] [Indexed: 02/07/2023] Open
Abstract
Children and adolescents are the largest at-risk group for the appearance of reflex seizures or epilepsy syndromes with a photoparoxysmal response. The aim of this study was to present an overview of the literature regarding photo-dependent reflex seizures. Epilepsy with seizures provoked by intermittent light stimulation is a distinct group of epilepsies; therefore, we focused on reflex seizures provoked by different factors whose common feature is the patient’s response to intermittent photic stimulation. A qualitative search of PubMed/MEDLINE, Scopus, EBSCO, and Cochrane Library electronic databases for selected terms was carried out for scientific articles published up to May 2020 outlining the outcomes of control, observational, and case studies. This scoping review was developed and followed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. The review of the qualitative evidence for the synthesis of photosensitive epilepsy allowed us to distinguish the following categories: light-induced seizures and light-deprived seizures. Differentiating between intermittent photic stimulation-related epilepsy syndromes and seizures is essential in order to determine the length of appropriate treatment. Photo-dependent reflex seizures make up the majority of this type of disorder among reflex seizures. Since there are many seizures provoking factors in the world around us, it is important to distinguish amongst them in order to be able to protect the patient exposed to this factor. It is recommended that the photostimulation procedure be performed during a routine electroencephalogram study.
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Affiliation(s)
- Jolanta Strzelecka
- Department of Pediatric Neurology, Medical University of Warsaw, 02-091 Warsaw, Poland;
- Correspondence: ; Tel.: +48-605-598-644
| | | | - Tymon Skadorwa
- Department of Descriptive and Clinical Anatomy, Medical University of Warsaw, 02-091 Warsaw, Poland;
| | - Jakub S. Gąsior
- Department of Pediatric Cardiology and General Pediatrics, Medical University of Warsaw, 02-091 Warsaw, Poland;
| | - Sergiusz Jóźwiak
- Department of Pediatric Neurology, Medical University of Warsaw, 02-091 Warsaw, Poland;
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24
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Improving user experience of SSVEP BCI through low amplitude depth and high frequency stimuli design. Sci Rep 2022; 12:8865. [PMID: 35614168 PMCID: PMC9132909 DOI: 10.1038/s41598-022-12733-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/09/2022] [Indexed: 11/08/2022] Open
Abstract
Steady-States Visually Evoked Potentials (SSVEP) refer to the sustained rhythmic activity observed in surface electroencephalography (EEG) in response to the presentation of repetitive visual stimuli (RVS). Due to their robustness and rapid onset, SSVEP have been widely used in Brain Computer Interfaces (BCI). However, typical SSVEP stimuli are straining to the eyes and present risks of triggering epileptic seizures. Reducing visual stimuli contrast or extending their frequency range both appear as relevant solutions to address these issues. It however remains sparsely documented how BCI performance is impacted by these features and to which extent user experience can be improved. We conducted two studies to systematically characterize the effects of frequency and amplitude depth reduction on SSVEP response. The results revealed that although high frequency stimuli improve visual comfort, their classification performance were not competitive enough to design a reliable/responsive BCI. Importantly, we found that the amplitude depth reduction of low frequency RVS is an effective solution to improve user experience while maintaining high classification performance. These findings were further validated by an online T9 SSVEP-BCI in which stimuli with 40% amplitude depth reduction achieved comparable results (>90% accuracy) to full amplitude stimuli while significantly improving user experience.
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25
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Wu L, Canna A, Narvaez O, Ma J, Sang S, Lehto LJ, Sierra A, Tanila H, Zhang Y, Gröhn O, Low WC, Filip P, Mangia S, Michaeli S. Orientation selective DBS of entorhinal cortex and medial septal nucleus modulates activity of rat brain areas involved in memory and cognition. Sci Rep 2022; 12:8565. [PMID: 35595790 PMCID: PMC9122972 DOI: 10.1038/s41598-022-12383-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 05/04/2022] [Indexed: 11/09/2022] Open
Abstract
The recently introduced orientation selective deep brain stimulation (OS-DBS) technique freely controls the direction of the electric field's spatial gradient by using multiple contacts with independent current sources within a multielectrode array. The goal of OS-DBS is to align the electrical field along the axonal track of interest passing through the stimulation site. Here we utilized OS-DBS with a planar 3-channel electrode for stimulating the rat entorhinal cortex (EC) and medial septal nucleus (MSN), two promising areas for DBS treatment of Alzheimer's disease. The brain responses to OS-DBS were monitored by whole brain functional magnetic resonance imaging (fMRI) at 9.4 T with Multi-Band Sweep Imaging with Fourier Transformation (MB-SWIFT). Varying the in-plane OS-DBS stimulation angle in the EC resulted in activity modulation of multiple downstream brain areas involved in memory and cognition. Contrary to that, no angle dependence of brain activations was observed when stimulating the MSN, consistent with predictions based on the electrode configuration and on the main axonal directions of the targets derived from diffusion MRI tractography and histology. We conclude that tuning the OS-DBS stimulation angle modulates the activation of brain areas relevant to Alzheimer's disease, thus holding great promise in the DBS treatment of the disease.
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Affiliation(s)
- Lin Wu
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Antonietta Canna
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA.,University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Omar Narvaez
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Jun Ma
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | - Sheng Sang
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Lauri J Lehto
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Alejandra Sierra
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Heikki Tanila
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Yuan Zhang
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - Olli Gröhn
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Walter C Low
- Department of Neurosurgery, University of Minnesota, Minneapolis, USA
| | - Pavel Filip
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA.,Department of Neurology, First Faculty of Medicine and General University Hospital, Charles University, Prague, Czech Republic
| | - Silvia Mangia
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Shalom Michaeli
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA. .,Radiology Department, Center for MR Research, University of Minnesota, 2021 6th St. SE, Minneapolis, MN, 55455, USA.
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26
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Siper PM, Rowe MA, Guillory SB, Rouhandeh AA, George-Jones JL, Tavassoli T, Lurie S, Zweifach J, Weissman J, Foss-Feig J, Halpern D, Trelles MP, Mulhern MS, Brittenham C, Gordon J, Zemon V, Buxbaum JD, Kolevzon A. Visual Evoked Potential Abnormalities in Phelan-McDermid Syndrome. J Am Acad Child Adolesc Psychiatry 2022; 61:565-574.e1. [PMID: 34303785 PMCID: PMC8782912 DOI: 10.1016/j.jaac.2021.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/28/2021] [Accepted: 07/15/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE The current study used visual evoked potentials (VEPs) to examine excitatory and inhibitory postsynaptic activity in children with Phelan-McDermid syndrome (PMS) and the association with genetic factors. PMS is caused by haploinsufficiency of SHANK3 on chromosome 22 and represents a common single-gene cause of autism spectrum disorder (ASD) and intellectual disability. METHOD Transient VEPs were obtained from 175 children, including 31 with PMS, 79 with idiopathic ASD, 45 typically developing controls, and 20 unaffected siblings of children with PMS. Stimuli included standard and short-duration contrast-reversing checkerboard conditions, and the reliability between these 2 conditions was assessed. Test-retest reliability and correlations with deletion size were explored in the group with PMS. RESULTS Children with PMS and, to a lesser extent, those with idiopathic ASD displayed significantly smaller amplitudes and decreased beta and gamma band activity relative to TD controls and PMS siblings. Across groups, high intraclass correlation coefficients were obtained between standard and short-duration conditions. In children with PMS, test-retest reliability was strong. Deletion size was significantly correlated with P60-N75 amplitude for both conditions. CONCLUSION Children with PMS displayed distinct transient VEP waveform abnormalities in both time and frequency domains that might reflect underlying glutamatergic deficits that were associated with deletion size. A similar response pattern was observed in a subset of children with idiopathic ASD. VEPs offer a noninvasive measure of excitatory and inhibitory neurotransmission that holds promise for stratification and surrogate endpoints in ongoing clinical trials in PMS and ASD.
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27
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Fisher RS, Acharya JN, Baumer FM, French JA, Parisi P, Solodar JH, Szaflarski JP, Thio LL, Tolchin B, Wilkins AJ, Kasteleijn-Nolst Trenité D. Visually sensitive seizures: An updated review by the Epilepsy Foundation. Epilepsia 2022; 63:739-768. [PMID: 35132632 DOI: 10.1111/epi.17175] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 12/19/2022]
Abstract
Light flashes, patterns, or color changes can provoke seizures in up to 1 in 4000 persons. Prevalence may be higher because of selection bias. The Epilepsy Foundation reviewed light-induced seizures in 2005. Since then, images on social media, virtual reality, three-dimensional (3D) movies, and the Internet have proliferated. Hundreds of studies have explored the mechanisms and presentations of photosensitive seizures, justifying an updated review. This literature summary derives from a nonsystematic literature review via PubMed using the terms "photosensitive" and "epilepsy." The photoparoxysmal response (PPR) is an electroencephalography (EEG) phenomenon, and photosensitive seizures (PS) are seizures provoked by visual stimulation. Photosensitivity is more common in the young and in specific forms of generalized epilepsy. PS can coexist with spontaneous seizures. PS are hereditable and linked to recently identified genes. Brain imaging usually is normal, but special studies imaging white matter tracts demonstrate abnormal connectivity. Occipital cortex and connected regions are hyperexcitable in subjects with light-provoked seizures. Mechanisms remain unclear. Video games, social media clips, occasional movies, and natural stimuli can provoke PS. Virtual reality and 3D images so far appear benign unless they contain specific provocative content, for example, flashes. Images with flashes brighter than 20 candelas/m2 at 3-60 (particularly 15-20) Hz occupying at least 10 to 25% of the visual field are a risk, as are red color flashes or oscillating stripes. Equipment to assay for these characteristics is probably underutilized. Prevention of seizures includes avoiding provocative stimuli, covering one eye, wearing dark glasses, sitting at least two meters from screens, reducing contrast, and taking certain antiseizure drugs. Measurement of PPR suppression in a photosensitivity model can screen putative antiseizure drugs. Some countries regulate media to reduce risk. Visually-induced seizures remain significant public health hazards so they warrant ongoing scientific and regulatory efforts and public education.
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Affiliation(s)
- Robert S Fisher
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Jayant N Acharya
- Department of Neurology, Penn State Health, Hershey, Pennsylvania, USA
| | - Fiona Mitchell Baumer
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Jacqueline A French
- NYU Comprehensive Epilepsy Center, Epilepsy Foundation, New York, New York, USA
| | - Pasquale Parisi
- Department of Neuroscience, Mental Health, and Sensory Organs, Sapienza University, Rome, Italy
| | - Jessica H Solodar
- American Medical Writers Association-New England Chapter, Boston, Massachusetts, USA
| | - Jerzy P Szaflarski
- Department of Neurology, Neurobiology and Neurosurgery, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, USA
| | - Liu Lin Thio
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Benjamin Tolchin
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA
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28
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Jiang L, Li X, Pei W, Gao X, Wang Y. A Hybrid Brain-Computer Interface Based on Visual Evoked Potential and Pupillary Response. Front Hum Neurosci 2022; 16:834959. [PMID: 35185500 PMCID: PMC8850273 DOI: 10.3389/fnhum.2022.834959] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/14/2022] [Indexed: 11/13/2022] Open
Abstract
Brain-computer interface (BCI) based on steady-state visual evoked potential (SSVEP) has been widely studied due to the high information transfer rate (ITR), little user training, and wide subject applicability. However, there are also disadvantages such as visual discomfort and “BCI illiteracy.” To address these problems, this study proposes to use low-frequency stimulations (12 classes, 0.8–2.12 Hz with an interval of 0.12 Hz), which can simultaneously elicit visual evoked potential (VEP) and pupillary response (PR) to construct a hybrid BCI (h-BCI) system. Classification accuracy was calculated using supervised and unsupervised methods, respectively, and the hybrid accuracy was obtained using a decision fusion method to combine the information of VEP and PR. Online experimental results from 10 subjects showed that the averaged accuracy was 94.90 ± 2.34% (data length 1.5 s) for the supervised method and 91.88 ± 3.68% (data length 4 s) for the unsupervised method, which correspond to the ITR of 64.35 ± 3.07 bits/min (bpm) and 33.19 ± 2.38 bpm, respectively. Notably, the hybrid method achieved higher accuracy and ITR than that of VEP and PR for most subjects, especially for the short data length. Together with the subjects’ feedback on user experience, these results indicate that the proposed h-BCI with the low-frequency stimulation paradigm is more comfortable and favorable than the traditional SSVEP-BCI paradigm using the alpha frequency range.
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Affiliation(s)
- Lu Jiang
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoyang Li
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Weihua Pei
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaorong Gao
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Yijun Wang
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
- Chinese Institute for Brain Research, Beijing, China
- *Correspondence: Yijun Wang,
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29
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Hine TJ, White YBZ. Pattern-Induced Visual Discomfort and Anxiety in Migraineurs: Their Relationship and the Effect of Colour. Vision (Basel) 2021; 6:vision6010001. [PMID: 35076617 PMCID: PMC8788433 DOI: 10.3390/vision6010001] [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: 07/04/2021] [Revised: 12/13/2021] [Accepted: 12/21/2021] [Indexed: 12/02/2022] Open
Abstract
In migraineurs, coloured lenses were found to reduce the visual stress caused by an aversive pattern known to trigger migraines by 70%, but do such patterns also produce a low-level anxiety/fear response? Is this response lessened by colour? We sought to investigate this in a study comprising a broad screening component followed by a dot-probe experiment to elicit attentional biases (AB) to aversive patterns. Undergraduate psychology students completed headache and visual discomfort (VD) questionnaires (N = 358), thereby forming a subject pool from which 13 migraineurs with high visual discomfort and 13 no-headache controls with low visual discomfort, matched on age and sex, completed a dot-probe experiment. Paired stimuli were presented for 500 ms: aversive achromatic 3 cpd square wave gratings vs control, scrambled patterns. These conditions were repeated using the colour that was most comfortable for each participant. VD was greater in the more severe headache groups. On all measures, the migraineurs were more anxious than the controls, and a positive relationship was found between VD and trait anxiety. The 3 cpd gratings elicited an aversive AB in the migraine group which was somewhat reduced by the use of colour, and this was not seen in the controls. The results suggest a new role for colour in reducing visual stress via anxiety/fear reduction.
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30
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Ascari L, Marchenkova A, Bellotti A, Lai S, Moro L, Koshmak K, Mantoan A, Barsotti M, Brondi R, Avveduto G, Sechi D, Compagno A, Avanzini P, Ambeck-Madsen J, Vecchiato G. Validation of a Novel Wearable Multistream Data Acquisition and Analysis System for Ergonomic Studies. SENSORS (BASEL, SWITZERLAND) 2021; 21:8167. [PMID: 34960261 PMCID: PMC8707223 DOI: 10.3390/s21248167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 12/02/2022]
Abstract
Nowadays, the growing interest in gathering physiological data and human behavior in everyday life scenarios is paralleled by an increase in wireless devices recording brain and body signals. However, the technical issues that characterize these solutions often limit the full brain-related assessments in real-life scenarios. Here we introduce the Biohub platform, a hardware/software (HW/SW) integrated wearable system for multistream synchronized acquisitions. This system consists of off-the-shelf hardware and state-of-art open-source software components, which are highly integrated into a high-tech low-cost solution, complete, yet easy to use outside conventional labs. It flexibly cooperates with several devices, regardless of the manufacturer, and overcomes the possibly limited resources of recording devices. The Biohub was validated through the characterization of the quality of (i) multistream synchronization, (ii) in-lab electroencephalographic (EEG) recordings compared with a medical-grade high-density device, and (iii) a Brain-Computer-Interface (BCI) in a real driving condition. Results show that this system can reliably acquire multiple data streams with high time accuracy and record standard quality EEG signals, becoming a valid device to be used for advanced ergonomics studies such as driving, telerehabilitation, and occupational safety.
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Affiliation(s)
- Luca Ascari
- Henesis s.r.l., 43123 Parma, Italy; (A.B.); (S.L.); (A.M.); (M.B.); (G.A.); (D.S.); (A.C.)
- Camlin Italy s.r.l., 43123 Parma, Italy; (L.M.); (K.K.); (R.B.)
| | - Anna Marchenkova
- Institute of Neuroscience, National Research Council of Italy, 43125 Parma, Italy; (A.M.); (P.A.)
| | - Andrea Bellotti
- Henesis s.r.l., 43123 Parma, Italy; (A.B.); (S.L.); (A.M.); (M.B.); (G.A.); (D.S.); (A.C.)
| | - Stefano Lai
- Henesis s.r.l., 43123 Parma, Italy; (A.B.); (S.L.); (A.M.); (M.B.); (G.A.); (D.S.); (A.C.)
| | - Lucia Moro
- Camlin Italy s.r.l., 43123 Parma, Italy; (L.M.); (K.K.); (R.B.)
| | | | - Alice Mantoan
- Henesis s.r.l., 43123 Parma, Italy; (A.B.); (S.L.); (A.M.); (M.B.); (G.A.); (D.S.); (A.C.)
| | - Michele Barsotti
- Henesis s.r.l., 43123 Parma, Italy; (A.B.); (S.L.); (A.M.); (M.B.); (G.A.); (D.S.); (A.C.)
| | | | - Giovanni Avveduto
- Henesis s.r.l., 43123 Parma, Italy; (A.B.); (S.L.); (A.M.); (M.B.); (G.A.); (D.S.); (A.C.)
| | - Davide Sechi
- Henesis s.r.l., 43123 Parma, Italy; (A.B.); (S.L.); (A.M.); (M.B.); (G.A.); (D.S.); (A.C.)
| | - Alberto Compagno
- Henesis s.r.l., 43123 Parma, Italy; (A.B.); (S.L.); (A.M.); (M.B.); (G.A.); (D.S.); (A.C.)
| | - Pietro Avanzini
- Institute of Neuroscience, National Research Council of Italy, 43125 Parma, Italy; (A.M.); (P.A.)
| | | | - Giovanni Vecchiato
- Institute of Neuroscience, National Research Council of Italy, 43125 Parma, Italy; (A.M.); (P.A.)
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31
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Brogin JAF, Faber J, Bueno DD. Burster Reconstruction Considering Unmeasurable Variables in the Epileptor Model. Neural Comput 2021; 33:3288-3333. [PMID: 34710900 DOI: 10.1162/neco_a_01443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 06/14/2021] [Indexed: 11/04/2022]
Abstract
Epilepsy is one of the most common brain disorders worldwide, affecting millions of people every year. Although significant effort has been put into better understanding it and mitigating its effects, the conventional treatments are not fully effective. Advances in computational neuroscience, using mathematical dynamic models that represent brain activities at different scales, have enabled addressing epilepsy from a more theoretical standpoint. In particular, the recently proposed Epileptor model stands out among these models, because it represents well the main features of seizures, and the results from its simulations have been consistent with experimental observations. In addition, there has been an increasing interest in designing control techniques for Epileptor that might lead to possible realistic feedback controllers in the future. However, such approaches rely on knowing all of the states of the model, which is not the case in practice. The work explored in this letter aims to develop a state observer to estimate Epileptor's unmeasurable variables, as well as reconstruct the respective so-called bursters. Furthermore, an alternative modeling is presented for enhancing the convergence speed of an observer. The results show that the proposed approach is efficient under two main conditions: when the brain is undergoing a seizure and when a transition from the healthy to the epileptiform activity occurs.
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Affiliation(s)
- João Angelo Ferres Brogin
- Department of Mechanical Engineering, School of Engineering of Ilha Solteira, São Paulo State University, Ilha Solteira, São Paulo, 15385-000, Brazil
| | - Jean Faber
- Department of Neurology and Neurosurgery, Federal University of São Paulo, São Paulo, 04039-032, Brazil
| | - Douglas Domingues Bueno
- Department of Mathematics, São Paulo State University, School of Engineering of Ilha Solteira, São Paulo, 15385-000, Brazil
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32
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de Pémille CV, Rekik S, Amiel H, Meppiel E, Richard A, Masmoudi S, Kubis N, Lozeron P. Contribution of intermittent photic stimulation to routine EEG. Neurophysiol Clin 2021; 51:549-553. [PMID: 34758911 DOI: 10.1016/j.neucli.2021.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 10/22/2021] [Accepted: 10/22/2021] [Indexed: 10/19/2022] Open
Abstract
OBJECTIVE Intermittent photic stimulation (IPS) is an activation procedure performed during electroencephalography (EEG) to detect photosensitive patients. This procedure is recommended in routine EEGs but the benefit of IPS in the general population is not clearly ascertained. METHODS We retrospectively analyzed 7683 EEGs of patients referred for a routine EEG to the Clinical Physiology Department of Lariboisière hospital, mainly from the emergency ward and the department of neurology, not specifically involved in epilepsy. All EEGs were performed with a standardized protocol. Photic driving response, photomyoclonic response and photoparoxysmal response (PPR) were specifically collected. A correlation analysis was performed between the response induced by IPS, demographical and clinical data, and current treatment or recreational drug use. RESULTS Median age was 56.4 years (41.7-71.2); 3,042 (39.6%) of patients were female; 1,208 patients (15.7%) had a past medical history of epilepsy. Photic driving response occurred in 67 EEGs (0.9%), and PPR in 6 EEGs (0.1%), all with a known history of epilepsy. Thus 0.5% (6/1,208) of epilepsy patients had a PPR. Photomyoclonic responses were not observed. Juvenile myoclonic epilepsy was the only factor associated with the presence of PPR (RR=75.26 [11.82-479.21]). PPR was not associated with clinical symptoms or seizures. There was no correlation with the type of treatment or recreational drug use. CONCLUSIONS Our results confirm that responses to IPS are rare in adult patients and especially PPR. Moreover, all patients with a PPR had a known previous history of epilepsy. These results question the benefit of IPS in adult patients with no history of epilepsy.
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Affiliation(s)
- Clément Vialatte de Pémille
- Service de Physiologie Clinique-Explorations Fonctionnelles, AP-HP, Hôpital Lariboisière, 2 rue Ambroise Paré, F-75010, Paris, France
| | - Saleheddine Rekik
- Service de Physiologie Clinique-Explorations Fonctionnelles, AP-HP, Hôpital Lariboisière, 2 rue Ambroise Paré, F-75010, Paris, France
| | - Hélène Amiel
- Service de Physiologie Clinique-Explorations Fonctionnelles, AP-HP, Hôpital Lariboisière, 2 rue Ambroise Paré, F-75010, Paris, France
| | - Elodie Meppiel
- Service de Physiologie Clinique-Explorations Fonctionnelles, AP-HP, Hôpital Lariboisière, 2 rue Ambroise Paré, F-75010, Paris, France
| | - Alexandra Richard
- Service de Physiologie Clinique-Explorations Fonctionnelles, AP-HP, Hôpital Lariboisière, 2 rue Ambroise Paré, F-75010, Paris, France
| | - Sana Masmoudi
- Service de Physiologie Clinique-Explorations Fonctionnelles, AP-HP, Hôpital Lariboisière, 2 rue Ambroise Paré, F-75010, Paris, France
| | - Nathalie Kubis
- Service de Physiologie Clinique-Explorations Fonctionnelles, AP-HP, Hôpital Lariboisière, 2 rue Ambroise Paré, F-75010, Paris, France; Université de Paris, Laboratory of Vascular and Translational Science, LVTS, U1148, F-75387, Paris, France
| | - Pierre Lozeron
- Service de Physiologie Clinique-Explorations Fonctionnelles, AP-HP, Hôpital Lariboisière, 2 rue Ambroise Paré, F-75010, Paris, France; Université de Paris, Laboratory of Vascular and Translational Science, LVTS, U1148, F-75387, Paris, France.
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Brinciotti M, Wilkins AJ, Penacchio O, Matricardi M. Pattern-sensitive patients with epilepsy use uncomfortable visual stimuli to self-induce seizures. Epilepsy Behav 2021; 122:108189. [PMID: 34252828 DOI: 10.1016/j.yebeh.2021.108189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/07/2021] [Accepted: 06/24/2021] [Indexed: 10/20/2022]
Abstract
Sensory stimuli can induce seizures in patients with epilepsy and predisposed subjects. Visual stimuli are the most common triggers, provoking seizures through an abnormal response to light or pattern. Sensitive patients may intentionally provoke their seizures through visual stimuli. Self-induction methods are widely described in photo-sensitive patients, while there are only a few reports of those who are pattern-sensitive. We analyzed 73 images of environmental visual triggers collected from 14 pattern-sensitive patients with self-induced seizures. The images were categorized according to their topics: 29 Objects (43%); 19 Patterns (28%); 15 External scenes (22%); 4 TV or computer screens (6%). Six photos were of poor quality and were excluded from analysis. Images were analyzed by an algorithm that calculated the degree to which the Fourier amplitude spectrum differed from that in images from nature. The algorithm has been shown to predict discomfort in healthy observers. The algorithm identified thirty-one images (46%) as "uncomfortable". There were significant differences between groups of images (ANOVA p = .0036; Chi2 p < .0279), with higher values of difference from nature in the images classified as "Objects" (mean 6,81E+11; SD 6,72E+11; n.17, 59%) and "Pattern" (mean 9,05E+11; SD 6,86E+11; n.14, 74%). During the semi-structured face-to-face interviews, all patients described the visual triggers as 'uncomfortable'; the appearance of enjoyable visual epileptic symptoms (especially multi-colored hallucinations) transformed uncomfortable images into pleasant stimuli. Patients considered self-induction as the simplest and most effective way to overcome stressful situations, suggesting that self-inducing pattern-sensitive patients often use uncomfortable visual stimuli to trigger their seizures. Among the reasons for the self-inducing behavior, the accidental discovery of pleasurable epileptic symptoms related to these "uncomfortable" visual stimuli should be considered.
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Affiliation(s)
- Mario Brinciotti
- Department of Human Neuroscience, Sapienza University of Rome, Italy.
| | | | - Olivier Penacchio
- School of Psychology and Neuroscience, University of St Andrews, United Kingdom.
| | - Maria Matricardi
- Department of Human Neuroscience, Sapienza University of Rome, Italy.
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Differences in visual information processing style between Idiopathic Generalized Epilepsy with and without photosensitivity. Epilepsy Behav 2021; 122:108183. [PMID: 34252831 DOI: 10.1016/j.yebeh.2021.108183] [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: 05/24/2021] [Revised: 06/15/2021] [Accepted: 06/15/2021] [Indexed: 11/22/2022]
Abstract
PURPOSE Recently, altered visual cortical processes i.e., lack of habituation to visual evoked potentials (VEP), has been highlighted in both photosensitive epilepsy and in a specific i.e., analytic mode of processing visual inputs. In this study we aimed at evaluating the relationship between photosensitivity (PS) and analytic style of processing visual information, in a sample of 30 patients with Idiopathic Generalized Epilepsy (IGE) and matched healthy controls. METHODS At our Epilepsy unit of the Sapienza University of Rome, we consecutively enrolled 15 patients with IGE with PSand matched them with 15 patients with IGE without PS and 15 Healthy Volunteers. All patients underwent EEG recording in basal conditions during hyperventilation (3 Min), and intermittent light stimulation. The most effective frequencies comprised from 12 to 16 Hz. The instruments used to gather psychological cognitive behavioral data, consisted of participation in two tests: the Sternberg-Wagner Self-Assessment Inventory and the Mariani Learning Style Questionnaire. RESULTS Compared to controls, both IGE groups show significantly higher scores for the analytic style (One-way ANOVA, F(2,44) = 110.3, p < 0.0001). Epilepsy groups thereby showed very distinctive cognitive styles as measured with the Sternberg test. In the visual style, scores of the photosensitive Individuals with IGE were significantly higher than the non-photosensitive individuals with IGE (p < 0.0001, Tukey's post hoc test). CONCLUSIONS An association between analytic style of processing visual information and PS in IGE has been shown. The common neurophysiological features between these two factors, suggest the possibility to evaluate this cognitive behavior as a potential target for nonpharmacological therapeutic strategies in photosensitive epilepsy.
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Abstract
Reflex seizures (RS) are epileptic events that are objectively and consistently elicited in response to a specific afferent stimulus or by an activity of the patient. The specific stimulus can be a variety of heterogenous intrinsic or extrinsic factors, ranging from the simple to the complex, such as flashing lights or reading a book. These seizures can take a variety of forms, comprising either general or focal onset, with or without secondary generalization. Reflex epilepsies (RE) are classified as a specific syndrome in which all epileptic seizures are precipitated by sensory stimuli. The few designated RE include idiopathic photosensitive occipital lobe epilepsy, other visual sensitive epilepsies, primary reading epilepsy, and startle epilepsy. RS that occurs within other focal or generalized epilepsy syndromes that are associated with distinct spontaneous seizures are classified by the overarching seizure type. Most patients experience spontaneous seizures along with their provoked events. RS originate from stimulation of functional anatomic networks normally functioning for physiological activities, that overlap or coincide with regions of cortical hyperexcitability. Generalized RS typically occur within the setting of IGEs and should be considered as focal seizures with quick secondary generalization via cortico-cortical or cortico-reticular pathways. In aggregate, activation of a critical neuronal mass, supported and sustained by cortico-subcortical and thalamocortical pathways eventually result in a seizure. Treatment includes antiseizure medication, commonly valproate or levetiracetam, along with lifestyle modifications, and when amenable, surgical intervention. High clinical suspicion and careful history taking must be employed in all epilepsy patients to identify reflex triggers.
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Affiliation(s)
- Samrina Hanif
- 1Department of Neurology, Marshall University, Joan C. Edwards School of Medicine, Huntington, WV 25701, USA
| | - Shane T Musick
- 2Department of Neurosurgery, Marshall University, Joan C. Edwards School of Medicine, Huntington, WV 25701, USA
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Cenobamate, a Sodium Channel Inhibitor and Positive Allosteric Modulator of GABA A Ion Channels, for Partial Onset Seizures in Adults: A Comprehensive Review and Clinical Implications. Neurol Int 2021; 13:252-265. [PMID: 34207493 PMCID: PMC8293325 DOI: 10.3390/neurolint13020026] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/19/2021] [Accepted: 05/29/2021] [Indexed: 12/16/2022] Open
Abstract
Medical management of epilepsy seeks to eliminate or to reduce the frequency of seizures, help patients maintain a normal lifestyle, and maintain psychosocial and occupational activities, while avoiding the negative side effects of long-term treatment. Current FDA approved drugs have been shown to have similar efficacy; however, they all share a commonality of having side effects that have the potential to significantly reduce a patient’s quality of life. Cenobamate, a newly-FDA approved drug used to treat partial-onset seizures in adult patients, has demonstrated promise in that it works on two proposed mechanisms that are commonly associated with epilepsy. Cenobamate acts as a positive allosteric modulator of the GABAA ion channels and is effective in reducing repetitive neuronal firing by inhibition of voltage-gated sodium channels, although the complete mechanism of action is currently unknown. The efficacy of Cenobamate with its low toxicity and adverse drug reaction profile emphasizes the need to further evaluate antiepileptic therapies containing sulfamoylphenyl and/or carbamate moieties in their chemical structure. Recent studies have found more patients to be seizure free during the maintenance period when compared to placebo. The most common side effects reported in with Cenobamate are somnolence, dizziness, headache, nausea, and fatigue. There are currently ongoing phase III studies looking to further evaluate the long-term benefits of Cenobamate and investigate adverse events.
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He Q, Colon‐Motas KM, Pybus AF, Piendel L, Seppa JK, Walker ML, Manzanares CM, Qiu D, Miocinovic S, Wood LB, Levey AI, Lah JJ, Singer AC. A feasibility trial of gamma sensory flicker for patients with prodromal Alzheimer's disease. ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2021; 7:e12178. [PMID: 34027028 PMCID: PMC8118113 DOI: 10.1002/trc2.12178] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 03/31/2021] [Indexed: 01/23/2023]
Abstract
INTRODUCTION We and collaborators discovered that flickering lights and sound at gamma frequency (40 Hz) reduce Alzheimer's disease (AD) pathology and alter immune cells and signaling in mice. To determine the feasibility of this intervention in humans we tested the safety, tolerability, and daily adherence to extended audiovisual gamma flicker stimulation. METHODS Ten patients with mild cognitive impairment due to underlying AD received 1-hour daily gamma flicker using audiovisual stimulation for 4 or 8 weeks at home with a delayed start design. RESULTS Gamma flicker was safe, tolerable, and adherable. Participants' neural activity entrained to stimulation. Magnetic resonance imaging and cerebral spinal fluid proteomics show preliminary evidence that prolonged flicker affects neural networks and immune factors in the nervous system. DISCUSSION These findings show that prolonged gamma sensory flicker is safe, tolerable, and feasible with preliminary indications of immune and network effects, supporting further study of gamma stimulation in AD.
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Affiliation(s)
- Qiliang He
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA
| | - Kay M. Colon‐Motas
- Department of NeurologyEmory Brain Health CenterEmory UniversityAtlantaGeorgiaUSA
| | - Alyssa F. Pybus
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA
- Parker H. Petit Institute for Bioengineering and BioscienceGeorgia Institute of TechnologyAtlantaGeorgiaUSA
- George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlantaGeorgiaUSA
| | - Lydia Piendel
- Department of NeurologyEmory Brain Health CenterEmory UniversityAtlantaGeorgiaUSA
| | - Jonna K. Seppa
- Department of NeurologyEmory Brain Health CenterEmory UniversityAtlantaGeorgiaUSA
| | - Margaret L. Walker
- Department of NeurologyEmory Brain Health CenterEmory UniversityAtlantaGeorgiaUSA
- Goizueta Alzheimer Disease Research CenterEmory UniversityAtlantaGeorgiaUSA
| | - Cecelia M. Manzanares
- Department of NeurologyEmory Brain Health CenterEmory UniversityAtlantaGeorgiaUSA
- Goizueta Alzheimer Disease Research CenterEmory UniversityAtlantaGeorgiaUSA
| | - Deqiang Qiu
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA
- Goizueta Alzheimer Disease Research CenterEmory UniversityAtlantaGeorgiaUSA
- Department of Radiology and Imaging SciencesEmory University School of MedicineAtlantaGeorgiaUSA
| | - Svjetlana Miocinovic
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA
- Department of NeurologyEmory Brain Health CenterEmory UniversityAtlantaGeorgiaUSA
- Goizueta Alzheimer Disease Research CenterEmory UniversityAtlantaGeorgiaUSA
| | - Levi B. Wood
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA
- Parker H. Petit Institute for Bioengineering and BioscienceGeorgia Institute of TechnologyAtlantaGeorgiaUSA
- George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlantaGeorgiaUSA
| | - Allan I. Levey
- Department of NeurologyEmory Brain Health CenterEmory UniversityAtlantaGeorgiaUSA
- Goizueta Alzheimer Disease Research CenterEmory UniversityAtlantaGeorgiaUSA
| | - James J. Lah
- Department of NeurologyEmory Brain Health CenterEmory UniversityAtlantaGeorgiaUSA
- Goizueta Alzheimer Disease Research CenterEmory UniversityAtlantaGeorgiaUSA
| | - Annabelle C. Singer
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA
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Lindquist LC, McIntire GR, Haigh SM. The effects of visual discomfort and chromaticity separation on neural processing during a visual task. Vision Res 2021; 182:27-35. [PMID: 33588291 PMCID: PMC7987861 DOI: 10.1016/j.visres.2021.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/13/2020] [Accepted: 01/14/2021] [Indexed: 01/23/2023]
Abstract
Visual stimuli that are uncomfortable to look at evoke a large neural response suggesting altered processing. While there is some evidence linking uncomfortable achromatic stimuli to impaired visual processing, the effect of uncomfortable chromatic patterns on visual cognition has yet to be explored. Large differences in chromaticity separation (e.g. red and blue) elicit visual discomfort, larger metabolic responses, larger visual evoked potentials, and greater alpha suppression compared to small chromaticity separations (e.g. pink and purple). We investigated the impact of stimuli that varied in their chromaticity separation (calculated in perceptual color space) on a visual task and their effect on neural responses across the cortex. Thirty participants completed a continuous pairs task (letters changed at 3 Hz) while grating patterns that differed in their chromaticity separation alternated with a grey screen at 5 Hz. The different temporal frequencies allowed for steady-state visual evoked potentials (SSVEPs) to the two stimulus-types to be measured simultaneously using electroencephalography (EEG). A subset of participants rated the gratings on a 9-point scale of discomfort. We observed greater ratings of discomfort and increased power at 5 Hz with the larger chromaticity separations. The increase in 5 Hz power with greater chromaticity separation was evident across the cortex. However, there was no significant effect of chromaticity separation on power at 3 Hz, or on reaction times, and no consistent effect on behavioral accuracy. Despite eliciting heightened neural responses across the cortex, short term exposure to uncomfortable chromatic stimuli does not adversely impact visual task performance.
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Affiliation(s)
- Lisa C Lindquist
- Center for Integrative Neuroscience, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557, United States
| | - Gregory R McIntire
- Center for Integrative Neuroscience, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557, United States
| | - Sarah M Haigh
- Center for Integrative Neuroscience, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557, United States.
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Nilo A, Crespel A, Genton P, Macorig G, Gigli GL, Gelisse P. Epilepsy with eyelid myoclonias (Jeavons syndrome): An electro-clinical study of 40 patients from childhood to adulthood. Seizure 2021; 87:30-38. [PMID: 33677402 DOI: 10.1016/j.seizure.2021.02.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/11/2021] [Accepted: 02/22/2021] [Indexed: 10/22/2022] Open
Abstract
PURPOSE To describe the typical and atypical clinical and electroencephalographic (EEG) features of 40 patients with Jeavons syndrome (JS). METHOD Retrospective analysis from two French tertiary centers. RESULTS Forty patients were enrolled (31 females and 9 males; sex ratio F/M = 3.44; mean age at epilepsy onset: 6.2 ± 3.4 years [range: 1-15 years]). A positive family history of generalized genetic epilepsy was reported by 13 patients (32.5 %). Eyelid myoclonias with or without absence were the seizure onset in 29 patients (72.5 %), and generalized tonic-clonic seizures in 11 (27.5 %). Over the course of the disease, all had absences. Intellectual disability and psychiatric disorders were reported in 14 (35 %) and 18 patients (45 %), respectively. Focal EEG abnormalities were observed in 65 % of patients, with a posterior (57.7 %) or anterior (30 %) distribution. Generalized EEG discharges were identified in 37 patients (92.5 %). Epileptiform abnormalities were activated during NREM sleep and increased upon awakening. Response to intermittent light stimulation (ILS) was observed in 34 patients (85 %), with an unusual pattern of epileptiform abnormalities at the same frequency of the flashes in 20 patients. Patients with all seizure types were more likely to have this response (p = 0.017). CONCLUSION JS is a lifelong genetic epileptic syndrome with onset in childhood, female preponderance, and a positive family history of epilepsy in one-third of the cases. Focal EEG abnormalities are frequent. Response to ILS appears different from other photosensitive syndromes, with an unusual pattern of photo-induced abnormal synchronization. Intellectual disability and psychiatric disorders are not rare.
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Affiliation(s)
- Annacarmen Nilo
- Epilepsy Unit, Hôpital Gui de Chauliac, Montpellier, France; Clinical Neurology Unit, Department of Neurosciences, S. Maria della Misericordia University Hospital, Udine, Italy
| | - Arielle Crespel
- Epilepsy Unit, Hôpital Gui de Chauliac, Montpellier, France; Research Unit (URCMA: Unité de Recherche sur les Comportements et Mouvements Anormaux), INSERM, U661, Montpellier, F-34000, France
| | | | - Greta Macorig
- Epilepsy Unit, Hôpital Gui de Chauliac, Montpellier, France; Neurology Unit, San Giovanni di Dio Hospital, Gorizia, Italy
| | - Gian Luigi Gigli
- Clinical Neurology Unit, Department of Neurosciences, S. Maria della Misericordia University Hospital, Udine, Italy; DMIF, University of Udine, Udine, Italy
| | - Philippe Gelisse
- Epilepsy Unit, Hôpital Gui de Chauliac, Montpellier, France; Research Unit (URCMA: Unité de Recherche sur les Comportements et Mouvements Anormaux), INSERM, U661, Montpellier, F-34000, France.
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40
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SSVEP phase synchronies and propagation during repetitive visual stimulation at high frequencies. Sci Rep 2021; 11:4975. [PMID: 33654157 PMCID: PMC7925656 DOI: 10.1038/s41598-021-83795-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 02/05/2021] [Indexed: 01/31/2023] Open
Abstract
Steady-state visual evoked potentials (SSVEPs), the brain response to visual flicker stimulation, have proven beneficial in both research and clinical applications. Despite the practical advantages of stimulation at high frequencies in terms of visual comfort and safety, high frequency-SSVEPs have not received enough attention and little is known about the mechanisms behind their generation and propagation in time and space. In this study, we investigated the origin and propagation of SSVEPs in the gamma frequency band (40-60 Hz) by studying the dynamic properties of EEG in 32 subjects. Using low-resolution brain electromagnetic tomography (sLORETA) we identified the cortical sources involved in SSVEP generation in that frequency range to be in the primary visual cortex, Brodmann areas 17, 18 and 19 with minor contribution from sources in central and frontal sites. We investigated the SSVEP propagation as measured on the scalp in the framework of the existing theories regarding the neurophysiological mechanism through which the SSVEP spreads through the cortex. We found a progressive phase shift from posterior parieto-occipital sites over the cortex with a phase velocity of approx. 8-14 m/s and wavelength of about 21 and 24 cm. The SSVEP spatial properties appear sensitive to input frequency with higher stimulation frequencies showing a faster propagation speed.
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Abstract
The prospect and potentiality of interfacing minds with machines has long captured human imagination. Recent advances in biomedical engineering, computer science, and neuroscience are making brain–computer interfaces a reality, paving the way to restoring and potentially augmenting human physical and mental capabilities. Applications of brain–computer interfaces are being explored in applications as diverse as security, lie detection, alertness monitoring, gaming, education, art, and human cognition augmentation. The present tutorial aims to survey the principal features and challenges of brain–computer interfaces (such as reliable acquisition of brain signals, filtering and processing of the acquired brainwaves, ethical and legal issues related to brain–computer interface (BCI), data privacy, and performance assessment) with special emphasis to biomedical engineering and automation engineering applications. The content of this paper is aimed at students, researchers, and practitioners to glimpse the multifaceted world of brain–computer interfacing.
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Seizure triggered by flicker electroretinogram in a patient with no history of epilepsy. Doc Ophthalmol 2020; 142:389-393. [PMID: 33355884 PMCID: PMC8116242 DOI: 10.1007/s10633-020-09813-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 12/11/2020] [Indexed: 11/16/2022]
Abstract
Purpose It is well known that repetitive flash stimulation may trigger seizures in susceptible individuals. Nevertheless, reports of such incidents occurring during recording of a flash electroretinogram (ERG) are extremely rare. Here, we describe the case of a photic-induced seizure triggered during an ERG recording in the absence of a history of epilepsy or other paroxysmal events. Methods A 14-year-old male patient presented with reduced visual acuity and impaired mesopic vision. Ophthalmological exams confirmed the patient’s complaints but were inconclusive as to the underlying pathophysiology. An ERG recording was performed, during which the 30-Hz flicker stimulus triggered a seizure. Results The ERG was essentially normal, with the exception of a 7-Hz rhythm superimposed onto the flicker ERG response that was recorded when the seizure developed. Conclusions The present case highlights the possibility that the 30-Hz ERG flash stimulus triggers a seizure in patients with no previous paroxysmal events. Literature evidence suggests that the likelihood of such an incident could be reduced by stimulating monocularly.
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Shirzhiyan Z, Keihani A, Farahi M, Shamsi E, GolMohammadi M, Mahnam A, Haidari MR, Jafari AH. Toward New Modalities in VEP-Based BCI Applications Using Dynamical Stimuli: Introducing Quasi-Periodic and Chaotic VEP-Based BCI. Front Neurosci 2020; 14:534619. [PMID: 33328841 PMCID: PMC7718037 DOI: 10.3389/fnins.2020.534619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 09/15/2020] [Indexed: 11/13/2022] Open
Abstract
Visual evoked potentials (VEPs) to periodic stimuli are commonly used in brain computer interfaces for their favorable properties such as high target identification accuracy, less training time, and low surrounding target interference. Conventional periodic stimuli can lead to subjective visual fatigue due to continuous and high contrast stimulation. In this study, we compared quasi-periodic and chaotic complex stimuli to common periodic stimuli for use with VEP-based brain computer interfaces (BCIs). Canonical correlation analysis (CCA) and coherence methods were used to evaluate the performance of the three stimulus groups. Subjective fatigue caused by the presented stimuli was evaluated by the Visual Analogue Scale (VAS). Using CCA with the M2 template approach, target identification accuracy was highest for the chaotic stimuli (M = 86.8, SE = 1.8) compared to the quasi-periodic (M = 78.1, SE = 2.6, p = 0.008) and periodic (M = 64.3, SE = 1.9, p = 0.0001) stimulus groups. The evaluation of fatigue rates revealed that the chaotic stimuli caused less fatigue compared to the quasi-periodic (p = 0.001) and periodic (p = 0.0001) stimulus groups. In addition, the quasi-periodic stimuli led to lower fatigue rates compared to the periodic stimuli (p = 0.011). We conclude that the target identification results were better for the chaotic group compared to the other two stimulus groups with CCA. In addition, the chaotic stimuli led to a less subjective visual fatigue compared to the periodic and quasi-periodic stimuli and can be suitable for designing new comfortable VEP-based BCIs.
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Affiliation(s)
- Zahra Shirzhiyan
- Computational Neuroscience, Institute of Medical Technology, Brandenburg University of Technology Cottbus-Senftenberg, Cottbus, Germany.,Department of Medical Physics & Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmadreza Keihani
- Department of Medical Physics & Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran University of Medical Sciences, Tehran, Iran
| | - Morteza Farahi
- Department of Medical Physics & Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran University of Medical Sciences, Tehran, Iran
| | - Elham Shamsi
- Department of Medical Physics & Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mina GolMohammadi
- Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran University of Medical Sciences, Tehran, Iran
| | - Amin Mahnam
- Department of Biomedical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran
| | - Mohsen Reza Haidari
- Section of Neuroscience, Department of Neurology, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Amir Homayoun Jafari
- Department of Medical Physics & Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran University of Medical Sciences, Tehran, Iran
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Behboodi M, Mahnam A, Marateb H, Rabbani H. Optimization of Visual Stimulus Sequence in a Brain-Computer Interface Based on Code Modulated Visual Evoked Potentials. IEEE Trans Neural Syst Rehabil Eng 2020; 28:2762-2772. [PMID: 33320813 DOI: 10.1109/tnsre.2020.3044947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Brain-computer interfaces based on code-modulated visual evoked potentials provide high information transfer rates, which make them promising alternative communication tools. Circular shifts of a binary sequence are used as the flickering pattern of several visual stimuli, where the minimum correlation between them is critical for recognizing the target by analyzing the EEG signal. Implemented sequences have been borrowed from communication theory without considering visual system physiology and related ergonomics. Here, an approach is proposed to design optimum stimulus sequences considering physiological factors, and their superior performance was demonstrated for a 6-target c-VEP BCI system. This was achieved by defining a time-factor index on the frequency response of the sequence, while the autocorrelation index ensured a low correlation between circular shifts. A modified version of the non-dominated sorting genetic algorithm II (NSGAII) multi-objective optimization technique was implemented to find, for the first time, 63-bit sequences with simultaneously optimized autocorrelation and time-factor indexes. The selected optimum sequences for general (TFO) and 6-target (6TO) BCI systems, were then compared with m-sequence by conducting experiments on 16 participants. Friedman tests showed a significant difference in perceived eye irritation between TFO and m-sequence (p = 0.024). Generalized estimating equations (GEE) statistical test showed significantly higher accuracy for 6TO compared to m-sequence (p = 0.006). Evaluation of EEG responses showed enhanced SNR for the new sequences compared to m-sequence, confirming the proposed approach for optimizing the stimulus sequence. Incorporating physiological factors to select sequence(s) used for c-VEP BCI systems improves their performance and applicability.
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Recommendations for Integrating a P300-Based Brain–Computer Interface in Virtual Reality Environments for Gaming: An Update. COMPUTERS 2020. [DOI: 10.3390/computers9040092] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The integration of a P300-based brain–computer interface (BCI) into virtual reality (VR) environments is promising for the video games industry. However, it faces several limitations, mainly due to hardware constraints and limitations engendered by the stimulation needed by the BCI. The main restriction is still the low transfer rate that can be achieved by current BCI technology, preventing movement while using VR. The goal of this paper is to review current limitations and to provide application creators with design recommendations to overcome them, thus significantly reducing the development time and making the domain of BCI more accessible to developers. We review the design of video games from the perspective of BCI and VR with the objective of enhancing the user experience. An essential recommendation is to use the BCI only for non-complex and non-critical tasks in the game. Also, the BCI should be used to control actions that are naturally integrated into the virtual world. Finally, adventure and simulation games, especially if cooperative (multi-user), appear to be the best candidates for designing an effective VR game enriched by BCI technology.
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Kocanaogullari D, Mak J, Kersey J, Khalaf A, Ostadabbas S, Wittenberg G, Skidmore E, Akcakaya M. EEG-based Neglect Detection for Stroke Patients. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:264-267. [PMID: 33017979 DOI: 10.1109/embc44109.2020.9176378] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Spatial neglect (SN) is a neurological syndrome in stroke patients, commonly due to unilateral brain injury. It results in inattention to stimuli in the contralesional visual field. The current gold standard for SN assessment is the behavioral inattention test (BIT). BIT includes a series of penand-paper tests. These tests can be unreliable due to high variablility in subtest performances; they are limited in their ability to measure the extent of neglect, and they do not assess the patients in a realistic and dynamic environment. In this paper, we present an electroencephalography (EEG)-based brain-computer interface (BCI) that utilizes the Starry Night Test to overcome the limitations of the traditional SN assessment tests. Our overall goal with the implementation of this EEG-based Starry Night neglect detection system is to provide a more detailed assessment of SN. Specifically, to detect the presence of SN and its severity. To achieve this goal, as an initial step, we utilize a convolutional neural network (CNN) based model to analyze EEG data and accordingly propose a neglect detection method to distinguish between stroke patients without neglect and stroke patients with neglect.Clinical relevance-The proposed EEG-based BCI can be used to detect neglect in stroke patients with high accuracy, specificity and sensitivity. Further research will additionally allow for an estimation of a patient's field of view (FOV) for more detailed assessment of neglect.
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Nilo A, Crespel A, Genton P, Macorig G, Gigli GL, Gelisse P. Spikes/spike-waves time-locked to the flash frequency during intermittent light stimulation in Jeavons syndrome. Clin Neurophysiol 2020; 131:2479-2481. [DOI: 10.1016/j.clinph.2020.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 10/23/2022]
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Rathore C, Prakash S, Makwana P. Prevalence of photoparoxysmal response in patients with epilepsy: Effect of the underlying syndrome and treatment status. Seizure 2020; 82:39-43. [PMID: 32979604 DOI: 10.1016/j.seizure.2020.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 10/23/2022] Open
Abstract
OBJECTIVE To prospectively study the prevalence of photoparoxysmal response (PPR) and its determinants in epilepsy patients. METHODS Consecutive patients, older than 2 years, undergoing EEG from January 2016 to December 2019 were prospectively studied for the presence of PPR. Patients with emergent EEG and those with only sleep record were excluded. Intermittent photic stimulation was performed as per standard techniques with frequencies from 1-30 Hz. RESULTS Of the 1893 subjects included, 1492 (78%) patients had epilepsy while 401 (22%) had other diagnoses. In epilepsy group, 1028 (68.7%) had focal epilepsy, 343 (21.6%) had generalized epilepsy, while (9.7%) patients had unclassified epilepsy. Overall, 36 (2.2%) patients with epilepsy had PPR. The mean age of these patients was 19.5 ± 9.4 years and 75% were females. PPR was noted in 5 (0.5%) patients with focal epilepsy and 31 (9%) patients with generalized epilepsies [p < 0.0001; Odds ratio: 20.3 (95% CI, 7.8 - 52.7)]. PPR was noted in 1.5% of treated and 18% of untreated patients with genetic generalized epilepsy (n = 145) and 22% of untreated patients with juvenile myoclonic epilepsy (n = 86). Patients with untreated epilepsy had 17 times higher odds of having PPR [p < 0.0001; Odds ratio: 17.6 (95% CI, 4.1 - 75.6)]. CONCLUSION Underlying epilepsy syndrome and treatment status are the two most important determinants of PPR. Variability in these two factors is largely responsible for the variable reported prevalence of PPR.
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Affiliation(s)
- Chaturbhuj Rathore
- Department of Neurology, Smt. B. K. Shah Medical Institute and Research Center, Sumandeep Vidyapeeth, Vadodara, Gujarat, India.
| | - Sanjay Prakash
- Department of Neurology, Smt. B. K. Shah Medical Institute and Research Center, Sumandeep Vidyapeeth, Vadodara, Gujarat, India
| | - Prayag Makwana
- Department of Neurology, Smt. B. K. Shah Medical Institute and Research Center, Sumandeep Vidyapeeth, Vadodara, Gujarat, India
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Brogin JAF, Faber J, Bueno DD. An Efficient Approach to Define the Input Stimuli to Suppress Epileptic Seizures Described by the Epileptor Model. Int J Neural Syst 2020; 30:2050062. [PMID: 32938259 DOI: 10.1142/s0129065720500628] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Epilepsy affects about 70 million people in the world. Every year, approximately 2.4 million people are diagnosed with epilepsy, two-thirds of them will not know the etiology of their disease, and 1% of these individuals will decease as a consequence of it. Due to the inherent complexity of predicting and explaining it, the mathematical model Epileptor was recently developed to reproduce seizure-like events, also providing insights to improve the understanding of the neural dynamics in the interictal and ictal periods, although the physics behind each parameter and variable of the model is not fully established in the literature. This paper introduces an approach to design a feedback-based controller for suppressing epileptic seizures described by Epileptor. Our work establishes how the nonlinear dynamics of this disorder can be written in terms of a combination of linear sub-models employing an exact solution. Additionally, we show how a feedback control gain can be computed to suppress seizures, as well as how specific shapes applied as input stimuli for this purpose can be obtained. The practical application of the approach is discussed and the results show that the proposed technique is promising for developing controllers in this field.
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Affiliation(s)
- João Angelo Ferres Brogin
- Department of Mechanical Engineering, São Paulo State University (UNESP), School of Engineering of Ilha Solteira, 56 Brasil Avenue, Ilha Solteira, São Paulo 15385-000, Brazil
| | - Jean Faber
- Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), 667 Pedro de Toledo Street, São Paulo 04039-032, Brazil
| | - Douglas Domingues Bueno
- Department of Mathematics, São Paulo State University (UNESP), School of Engineering of Ilha Solteira, 56 Brasil Avenue, Ilha Solteira, São Paulo 15385-000, Brazil
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Hua HU, Pieramici DJ, Bagheri N. Understanding seizure risk with wide field fundus photography: Implications for screening guidelines in the era of COVID-19 and telemedicine. Am J Ophthalmol Case Rep 2020; 19:100844. [PMID: 32803018 PMCID: PMC7405818 DOI: 10.1016/j.ajoc.2020.100844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/26/2020] [Accepted: 07/28/2020] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To report two cases of photosensitive seizures due to fundus photography flash. OBSERVATIONS Two patients with seizure history present to a retina clinic for routine follow up. While obtaining imaging, these patients experienced a seizure triggered by fundus camera flash. CONCLUSIONS Fundus photography is essential and ubiquitous amongst optometry and ophthalmology practices, especially in the rising era of telemedicine in the setting of the recent COVID-19 pandemic. To our knowledge, there are no other reports in the literature of seizures triggered by fundus photography flash. However, we believe this to be an under-reported phenomenon and suggest that all eye care providers screen patients for a history of seizures or epilepsy prior to fundus photography.
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Affiliation(s)
- Hong-Uyen Hua
- Roski Eye Institute, Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA
| | - Dante J. Pieramici
- California Retina Consultants and Research Foundation, Santa Barbara, CA, USA
| | - Nika Bagheri
- California Retina Consultants and Research Foundation, Santa Barbara, CA, USA
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