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Petro NM, Webert LK, Springer SD, Okelberry HJ, John JA, Horne LK, Glesinger R, Rempe MP, Wilson TW. Optimal gamma-band entrainment of visual cortex. Hum Brain Mapp 2024; 45:e26775. [PMID: 38970249 PMCID: PMC11226544 DOI: 10.1002/hbm.26775] [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: 01/23/2024] [Revised: 05/29/2024] [Accepted: 06/17/2024] [Indexed: 07/08/2024] Open
Abstract
Visual entrainment is a powerful and widely used research tool to study visual information processing in the brain. While many entrainment studies have focused on frequencies around 14-16 Hz, there is renewed interest in understanding visual entrainment at higher frequencies (e.g., gamma-band entrainment). Notably, recent groundbreaking studies have demonstrated that gamma-band visual entrainment at 40 Hz may have therapeutic effects in the context of Alzheimer's disease (AD) by stimulating specific neural ensembles, which utilize GABAergic signaling. Despite such promising findings, few studies have investigated the optimal parameters for gamma-band visual entrainment. Herein, we examined whether visual stimulation at 32, 40, or 48 Hz produces optimal visual entrainment responses using high-density magnetoencephalography (MEG). Our results indicated strong entrainment responses localizing to the primary visual cortex in each condition. Entrainment responses were stronger for 32 and 40 Hz relative to 48 Hz, indicating more robust synchronization of neural ensembles at these lower gamma-band frequencies. In addition, 32 and 40 Hz entrainment responses showed typical patterns of habituation across trials, but this effect was absent for 48 Hz. Finally, connectivity between visual cortex and parietal and prefrontal cortices tended to be strongest for 40 relative to 32 and 48 Hz entrainment. These results suggest that neural ensembles in the visual cortex may resonate at around 32 and 40 Hz and thus entrain more readily to photic stimulation at these frequencies. Emerging AD therapies, which have focused on 40 Hz entrainment to date, may be more effective at lower relative to higher gamma frequencies, although additional work in clinical populations is needed to confirm these findings. PRACTITIONER POINTS: Gamma-band visual entrainment has emerged as a therapeutic approach for eliminating amyloid in Alzheimer's disease, but its optimal parameters are unknown. We found stronger entrainment at 32 and 40 Hz compared to 48 Hz, suggesting neural ensembles prefer to resonate around these relatively lower gamma-band frequencies. These findings may inform the development and refinement of innovative AD therapies and the study of GABAergic visual cortical functions.
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Affiliation(s)
- Nathan M. Petro
- Institute for Human NeuroscienceBoys Town National Research HospitalBoys TownNebraskaUSA
| | - Lauren K. Webert
- Institute for Human NeuroscienceBoys Town National Research HospitalBoys TownNebraskaUSA
| | - Seth D. Springer
- Institute for Human NeuroscienceBoys Town National Research HospitalBoys TownNebraskaUSA
- College of MedicineUniversity of Nebraska Medical Center (UNMC)OmahaNebraskaUSA
| | - Hannah J. Okelberry
- Institute for Human NeuroscienceBoys Town National Research HospitalBoys TownNebraskaUSA
| | - Jason A. John
- Institute for Human NeuroscienceBoys Town National Research HospitalBoys TownNebraskaUSA
| | - Lucy K. Horne
- Institute for Human NeuroscienceBoys Town National Research HospitalBoys TownNebraskaUSA
| | - Ryan Glesinger
- Institute for Human NeuroscienceBoys Town National Research HospitalBoys TownNebraskaUSA
| | - Maggie P. Rempe
- Institute for Human NeuroscienceBoys Town National Research HospitalBoys TownNebraskaUSA
- College of MedicineUniversity of Nebraska Medical Center (UNMC)OmahaNebraskaUSA
| | - Tony W. Wilson
- Institute for Human NeuroscienceBoys Town National Research HospitalBoys TownNebraskaUSA
- College of MedicineUniversity of Nebraska Medical Center (UNMC)OmahaNebraskaUSA
- Department of Pharmacology and NeuroscienceCreighton UniversityOmahaNebraskaUSA
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van Asch CJJ, Spetgens WPJ, Bourez-Swart MD, Meppelink AM, Deckers CLP, van Blooijs D, Kasteleijn-Nolst Trenité DGA. Photosensitivity and self-induction in patients aged 50 and older. Epileptic Disord 2024. [PMID: 38497935 DOI: 10.1002/epd2.20209] [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: 11/23/2023] [Revised: 01/26/2024] [Accepted: 02/07/2024] [Indexed: 03/19/2024]
Abstract
OBJECTIVE Photosensitivity is known to occur predominantly in children and adolescents and with a clear female predominance. Little is known on the prevalence of photosensitivity in older patients (50+) and its phenotypical appearance. METHODS A retrospective observational study was performed investigating the prevalence of a photoparoxysmal EEG response (PPR) on at least one EEG during the period 2015-2021. Data were gathered from patients aged 50 years and older by retrieving clinical and EEG characteristics from existing medical records. Data on photosensitivity-related symptoms in daily life were gathered with telephone interviewing. RESULTS In 248 patients a PPR had been elicited, of whom 16 patients (6.5%) were 50 years or older. In older patients, photosensitivity was a persistent feature of childhood-onset epilepsy (n = 8), of adult-onset epilepsy (n = 7), or an incidental finding (n = 1). In the 50+ group, 56% of photosensitive patients was female, whereas 72% in the total PPR-group. In six of 16 older patients, eye closure sensitivity was observed; two of these patients reported self-induction. Symptoms of photosensitivity in daily life were present in eight out of nine patients who consented in a telephone interview. For seven of these patients, wearing sunglasses was helpful. SIGNIFICANCE Female preponderance for photosensitivity was not found in epilepsy patients of 50 years and older. In 44% of the older photosensitive patients in this series, the PPR was a feature of adult-onset epilepsy. Symptoms of photosensitivity in daily life in older patients with epilepsy seem comparable to those in younger patients, and thus worthwhile to diagnose and treat them equally.
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Affiliation(s)
- C J J van Asch
- Stichting Epilepsie Instellingen Nederland (SEIN), Hoofddorp, The Netherlands
| | - W P J Spetgens
- Stichting Epilepsie Instellingen Nederland (SEIN), Hoofddorp, The Netherlands
- University Medical Center Utrecht, Utrecht, The Netherlands
| | - M D Bourez-Swart
- Stichting Epilepsie Instellingen Nederland (SEIN), Hoofddorp, The Netherlands
| | - A M Meppelink
- Stichting Epilepsie Instellingen Nederland (SEIN), Hoofddorp, The Netherlands
| | - C L P Deckers
- Stichting Epilepsie Instellingen Nederland (SEIN), Hoofddorp, The Netherlands
| | - D van Blooijs
- Stichting Epilepsie Instellingen Nederland (SEIN), Hoofddorp, The Netherlands
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3
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Peltola ME, Leitinger M, Halford JJ, Vinayan KP, Kobayashi K, Pressler RM, Mindruta I, Mayor LC, Lauronen L, Beniczky S. Routine and sleep EEG: Minimum recording standards of the International Federation of Clinical Neurophysiology and the International League Against Epilepsy. Epilepsia 2023; 64:602-618. [PMID: 36762397 PMCID: PMC10006292 DOI: 10.1111/epi.17448] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/18/2022] [Accepted: 10/25/2022] [Indexed: 02/11/2023]
Abstract
This article provides recommendations on the minimum standards for recording routine ("standard") and sleep electroencephalography (EEG). The joint working group of the International Federation of Clinical Neurophysiology (IFCN) and the International League Against Epilepsy (ILAE) developed the standards according to the methodology suggested for epilepsy-related clinical practice guidelines by the Epilepsy Guidelines Working Group. We reviewed the published evidence using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The quality of evidence for sleep induction methods was assessed by the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method. A tool for Quality Assessment of Diagnostic Studies (QUADAS-2) was used to assess the risk of bias in technical and methodological studies. Where high-quality published evidence was lacking, we used modified Delphi technique to reach expert consensus. The GRADE system was used to formulate the recommendations. The quality of evidence was low or moderate. We formulated 16 consensus-based recommendations for minimum standards for recording routine and sleep EEG. The recommendations comprise the following aspects: indications, technical standards, recording duration, sleep induction, and provocative methods.
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Affiliation(s)
- Maria E Peltola
- HUS Diagnostic Center, Clinical Neurophysiology, Clinical Neurosciences, Epilepsia Helsinki, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Markus Leitinger
- Department of Neurology, Christian Doppler University Hospital, Paracelsus Medical University, Salzburg, Austria
| | - Jonathan J Halford
- Department of Neurology, Medical University of South Carolina, Charleston, South Carolina, USA
| | | | - Katsuhiro Kobayashi
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Ronit M Pressler
- Clinical Neuroscience, UCL-Great Ormond Street Institute of Child Health and Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Ioana Mindruta
- Department of Neurology, University Emergency Hospital of Bucharest and University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
| | - Luis Carlos Mayor
- Department of Neurology, Hospital Universitario Fundacion Santa Fe de Bogota, Bogota, Colombia
| | - Leena Lauronen
- HUS Diagnostic Center, Clinical Neurophysiology, Clinical Neurosciences, Epilepsia Helsinki, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Sándor Beniczky
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, and Danish Epilepsy Centre, Dianalund, Denmark
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4
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Peltola ME, Leitinger M, Halford JJ, Vinayan KP, Kobayashi K, Pressler RM, Mindruta I, Mayor LC, Lauronen L, Beniczky S. Routine and sleep EEG: Minimum recording standards of the International Federation of Clinical Neurophysiology and the International League Against Epilepsy. Clin Neurophysiol 2023; 147:108-120. [PMID: 36775678 DOI: 10.1016/j.clinph.2023.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
This article provides recommendations on the minimum standards for recording routine ("standard") and sleep electroencephalography (EEG). The joint working group of the International Federation of Clinical Neurophysiology (IFCN) and the International League Against Epilepsy (ILAE) developed the standards according to the methodology suggested for epilepsy-related clinical practice guidelines by the Epilepsy Guidelines Working Group. We reviewed the published evidence using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The quality of evidence for sleep induction methods was assessed by the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method. A tool for Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used to assess the risk of bias in technical and methodological studies. Where high-quality published evidence was lacking, we used modified Delphi technique to reach expert consensus. The GRADE system was used to formulate the recommendations. The quality of evidence was low or moderate. We formulated 16 consensus-based recommendations for minimum standards for recording routine and sleep EEG. The recommendations comprise the following aspects: indications, technical standards, recording duration, sleep induction, and provocative methods.
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Affiliation(s)
- Maria E Peltola
- HUS Diagnostic Center, Clinical Neurophysiology, Clinical Neurosciences, Epilepsia Helsinki, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
| | - Markus Leitinger
- Department of Neurology, Christian Doppler University Hospital, Paracelsus Medical University, Salzburg, Austria
| | - Jonathan J Halford
- Department of Neurology, Medical University of South Carolina, Charleston, SC, USA
| | | | - Katsuhiro Kobayashi
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Ronit M Pressler
- Clinical Neuroscience, UCL-Great Ormond Street Institute of Child Health and Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Ioana Mindruta
- Department of Neurology, University Emergency Hospital of Bucharest and University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
| | - Luis Carlos Mayor
- Department of Neurology, Hospital Universitario Fundacion Santa Fe de Bogota, Bogota, Colombia
| | - Leena Lauronen
- HUS Diagnostic Center, Clinical Neurophysiology, Clinical Neurosciences, Epilepsia Helsinki, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Sándor Beniczky
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, and Danish Epilepsy Centre, Dianalund, Denmark
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5
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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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Bai J, Zhang WJ, Ruan ZF, Chen BB, Zhao G, Wang D, Dang JX, Liu YH. Photosensitive epilepsy and photosensitivity of patients with possible epilepsy in Chinese Han race: A prospective multicenter study. J Clin Neurosci 2019; 69:15-20. [PMID: 31526678 DOI: 10.1016/j.jocn.2019.08.086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 07/24/2019] [Accepted: 08/18/2019] [Indexed: 11/16/2022]
Abstract
Photosensitive is probably caused by multiple factors including gender, familiar, etc. We aim to study the clinical and EEG features of Chinese Han patients with photosensitivity. A total of 5482 consecutive patients with possible epilepsy from 3 center in China. Of the 73 patients with PPR to IPS, 48 were female. 69.9% patients were evoked by frequency ranged 8 Hz-25 Hz, with accompanying seizures in 13 patients. 6 of 9 patients with eyes closure sensitivity experienced epileptic seizures during IPS. We found some new features: 1) The patients with eyes closure sensitivity apt to experience electro-clinical seizures provoked by IPS; 2) Female epilepsy patients with PPR and ECS maybe difficult to be seizure free. Preventive measures for related seizures should be performed to the patients with generalized PPR, upper threshold evoking frequency, and eyes closure sensitivity when they received the IPS.
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Affiliation(s)
- Jie Bai
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, PR China
| | - Wen-Juan Zhang
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, PR China
| | - Zhi-Fang Ruan
- Department of Neurology, 180 Hospital of Chinese PLA, Quanzhou 362000, PR China
| | - Bei-Bei Chen
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, PR China
| | - Gang Zhao
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, PR China
| | - Dong Wang
- Department of Neurology, Pediatric Hospital, Xi'an Jiaotong University, Xi'an 710003, PR China
| | - Jing-Xia Dang
- Department of Neurology, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, PR China
| | - Yong-Hong Liu
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, PR China.
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7
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Photosensitivity and epilepsy: Current concepts and perspectives-A narrative review. Seizure 2017; 50:209-218. [PMID: 28532712 DOI: 10.1016/j.seizure.2017.04.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 01/15/2023] Open
Abstract
The authors review the influence of photic stimuli on the generation of epileptic seizures, addressing the first descriptions of the phenomenon and its subsequent exploration. Initially defined in the 1950's, links between intermittent photic stimulation (IPS) and seizures were well understood by the 1970. Since then the increasing exposure to photic stimuli associated with modern life (for instance through TVs, patterns, computer games and electronic instruments with flickering displays) has led to an increased interest in this issue. Diverse stimulation procedures have been described and difference in the effects of stimulation frequencies and types, colour and lighting have been recognised. Approximately 5% of patients with epilepsy have photosensitive epilepsy (PSE). PSE is commoner in younger individuals, more frequent in women, often time-limited, generally easy to treat and closely related to generalised epilepsies, especially Juvenile Myoclonic Epilepsy (JME). Structural and functional studies of PSE indicate abnormalities beyond the frontal lobes and evidence for the role of the visual cortex in human PSE. A reduction in connectivity between prefrontal and frontopolar regions and increased connectivity between occipital cortex and the supplementary motor area may be the basis for triggering motor seizures in JME. Due to the changes observed in such areas, it is hypothesised that photoparoxysmal responses (PPR) could be a final expression of pathogenic phenomena in the striato-thalamocortical system, and possibly a core feature of JME as system epilepsy. The familial transmission of epileptiform responses to IPS is well-recognised, but no clear relation between PSE and specific genes has emerged. Although the influence of ethnic factors on PSE has been widely studied, clear conclusions are still lacking. Pharmacological therapeutic approaches are beyond the scope of this review although preventive measures allowing patients to avoid PS seizure initiation and/or generalisation are discussed. Given the gender/age group most commonly affected by PSE, the risks and benefits of drug treatment need to be carefully weighed up.
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Strigaro G, Prandi P, Varrasi C, Magistrelli L, Falletta L, Cantello R. Intermittent photic stimulation affects motor cortex excitability in photosensitive idiopathic generalized epilepsy. Epilepsy Res 2013; 104:78-83. [DOI: 10.1016/j.eplepsyres.2012.08.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Revised: 08/19/2012] [Accepted: 08/26/2012] [Indexed: 10/27/2022]
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9
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Strigaro G, Prandi P, Varrasi C, Monaco F, Cantello R. Defective visual inhibition in photosensitive idiopathic generalized epilepsy. Epilepsia 2012; 53:695-704. [DOI: 10.1111/j.1528-1167.2012.03411.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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10
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Spiegler A, Knösche TR, Schwab K, Haueisen J, Atay FM. Modeling brain resonance phenomena using a neural mass model. PLoS Comput Biol 2011; 7:e1002298. [PMID: 22215992 PMCID: PMC3245303 DOI: 10.1371/journal.pcbi.1002298] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 10/25/2011] [Indexed: 11/22/2022] Open
Abstract
Stimulation with rhythmic light flicker (photic driving) plays an important role in the diagnosis of schizophrenia, mood disorder, migraine, and epilepsy. In particular, the adjustment of spontaneous brain rhythms to the stimulus frequency (entrainment) is used to assess the functional flexibility of the brain. We aim to gain deeper understanding of the mechanisms underlying this technique and to predict the effects of stimulus frequency and intensity. For this purpose, a modified Jansen and Rit neural mass model (NMM) of a cortical circuit is used. This mean field model has been designed to strike a balance between mathematical simplicity and biological plausibility. We reproduced the entrainment phenomenon observed in EEG during a photic driving experiment. More generally, we demonstrate that such a single area model can already yield very complex dynamics, including chaos, for biologically plausible parameter ranges. We chart the entire parameter space by means of characteristic Lyapunov spectra and Kaplan-Yorke dimension as well as time series and power spectra. Rhythmic and chaotic brain states were found virtually next to each other, such that small parameter changes can give rise to switching from one to another. Strikingly, this characteristic pattern of unpredictability generated by the model was matched to the experimental data with reasonable accuracy. These findings confirm that the NMM is a useful model of brain dynamics during photic driving. In this context, it can be used to study the mechanisms of, for example, perception and epileptic seizure generation. In particular, it enabled us to make predictions regarding the stimulus amplitude in further experiments for improving the entrainment effect. Neuroscience aims to understand the enormously complex function of the normal and diseased brain. This, in turn, is the key to explaining human behavior and to developing novel diagnostic and therapeutic procedures. We develop and use models of mean activity in a single brain area, which provide a balance between tractability and plausibility. We use such a model to explain the resonance phenomenon in a photic driving experiment, which is routinely applied in the diagnosis of various diseases including epilepsy, migraine, schizophrenia and depression. Based on the model, we make predictions on the outcome of similar resonance experiments with periodic stimulation of the patients or participants. Our results are important for researchers and clinicians analyzing brain or behavioral data following periodic input.
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Affiliation(s)
- Andreas Spiegler
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
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Kasteleijn-Nolst Trenité D, Rubboli G, Hirsch E, Martins da Silva A, Seri S, Wilkins A, Parra J, Covanis A, Elia M, Capovilla G, Stephani U, Harding G. Methodology of photic stimulation revisited: Updated European algorithm for visual stimulation in the EEG laboratory. Epilepsia 2011; 53:16-24. [DOI: 10.1111/j.1528-1167.2011.03319.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Brosch JR, Golomb MR. Seizures triggered by July 4th fireworks in an 8-year-old girl with perinatal stroke. J Child Neurol 2011; 26:638-41. [PMID: 21464238 DOI: 10.1177/0883073810387927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Warnings regarding fireworks displays as a possible seizure-producing stimulus have been around for several years, but there is a lack of well-documented cases. This case describes photic- and/or pattern-induced seizures that appeared to be triggered by July 4 fireworks. This 8-year-old girl with hemiplegic cerebral palsy and known seizure disorder because of perinatal right middle cerebral artery stroke had a cluster of seizures within minutes of the onset of a professional fireworks display. The seizures stopped when the child's eyes were covered and she was taken away from the scene. The importance of photic- and pattern-induced seizures in children is discussed.
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Affiliation(s)
- Jared R Brosch
- Indiana University School of Medicine, Department of Neurology, Division of Pediatric Neurology, Indianapolis, Indiana 46202, USA
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Parra J, Lopes da Silva FH, Stroink H, Kalitzin S. Is colour modulation an independent factor in human visual photosensitivity? Brain 2007; 130:1679-89. [PMID: 17525144 DOI: 10.1093/brain/awm103] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Considering that the role of colour in photosensitive epilepsy (PSE) remains unclear, we designed a study to determine the potential of different colours, colour combinations and white light to trigger photoparoxysmal responses (PPRs) under stringent controlled conditions. After assessing their photosensitivity to stroboscopic white light and black and white patterns, we studied 43 consecutive PSE patients (mean age 19 years, 34 women), using a specially designed colour stimulator. Stimuli included: pulse trains between 10 and 30 Hz of white light and of all primary colours, and also isoluminant alternating time-sequences of colours. Illuminance was kept constant at 100 lux. A progressive stepwise increase of the modulation-depth (MD) of the stimuli was used to determine PPRs threshold. Whereas all the 43 patients were found to be sensitive during the stroboscopic and pattern protocol, only 25 showed PPRs (Waltz's score >2) at least in one session when studied with the colour stimulator. Coloured stimuli elicited PPRs in all these patients, whereas white light did so only in 17 patients. Of the primary colours, red elicited more PPRs (54 in 22 patients) and at a lower MD (max Z-score 0.93 at 10 Hz). Of the alternating sequences, the red-blue was the most provocative stimulus, especially below 30 Hz (100% of patients, max Z-score: 1.65 at 15 Hz). Blue-green was the least provocative stimulus, since it elicited only seven PPRs in seven (28%) patients (max Z-score 0.44 at 10 Hz). Sensitivity to alternating colours was not correlated to sensitivity to individual colours. We conclude that colour sensitivity follows two different mechanisms: one, dependent on colour modulation, plays a role at lower frequencies (<30 Hz). Another, dependent on single-colour light intensity modulation correlates to white light sensitivity and is activated at higher frequencies. Our results suggest that the prescription of spectacles with coloured lenses, tailored to the patient, can be an effective preventative measure against visually induced seizures.
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Affiliation(s)
- Jaime Parra
- Dutch Epilepsy Clinics Foundation, SEIN, Meer en Bosch, Heemstede, The Netherlands.
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Verrotti A, Tocco AM, Salladini C, Latini G, Chiarelli F. Human photosensitivity: from pathophysiology to treatment. Eur J Neurol 2005; 12:828-41. [PMID: 16241971 DOI: 10.1111/j.1468-1331.2005.01085.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photosensitivity is a condition detected on the electroencephalography (EEG) as a paroxysmal reaction to Intermittent Photic Stimulation (IPS). This EEG response, elicited by IPS or by other visual stimuli of daily life, is called Photo Paroxysmal Response (PPR). PPRs are well documented in epileptic and non-epileptic subjects. Photosensitivity rarely in normal individuals evolves into epilepsy. Photosensitive epilepsy is a rare refex epilepsy characterized by seizures in photosensitive individuals. The development of modern technology has increased the exposition to potential seizure precipitants in people of all ages, but especially in children and adolescents. Actually, videogames, computers and televisions are the most common triggers in daily life of susceptible persons. The mechanisms of generation of PPR are poorly understood, but genetic factors play an important rule. The control of visually induced seizures has, generally a good prognosis. In patients known to be visually sensitive, avoidance of obvious source and stimulus modifications are very important and useful to seizure prevention, but in the large majority of patients with epilepsy and photosensitivity antiepileptic drugs are needed.
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Affiliation(s)
- A Verrotti
- Department of Medicine, Section of Pediatrics, University of Chieti, Chieti, Italy.
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Fisher RS, Harding G, Erba G, Barkley GL, Wilkins A. Photic- and pattern-induced seizures: a review for the Epilepsy Foundation of America Working Group. Epilepsia 2005; 46:1426-41. [PMID: 16146439 DOI: 10.1111/j.1528-1167.2005.31405.x] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE This report summarizes background material presented to a consensus conference on visually provoked seizures, convened by the Epilepsy Foundation of America. METHODS A comprehensive review of literature was performed. RESULTS Photosensitivity, an abnormal EEG response to light or pattern stimulation, occurs in approximately 0.3-3% of the population. The estimated prevalence of seizures from light stimuli is approximately 1 per 10,000, or 1 per 4,000 individuals age 5-24 years. People with epilepsy have a 2-14% chance of having seizures precipitated by light or pattern. In the Pokemon cartoon incident in Japan, 685 children visited a hospital in reaction to red-blue flashes on broadcast television (TV). Only 24% who had a seizure during the cartoon had previously experienced a seizure. Photic or pattern stimulation can provoke seizures in predisposed individuals, but such stimulation is not known to increase the chance of subsequent epilepsy. Intensities of 0.2-1.5 million candlepower are in the range to trigger seizures. Frequencies of 15-25 Hz are most provocative, but the range is 1-65 Hz. Light-dark borders can induce pattern-sensitive seizures, and red color also is a factor. Seizures can be provoked by certain TV shows, movie screen images, video games, natural stimuli (e.g, sun on water), public displays, and many other sources. CONCLUSIONS Recommendations on reducing risk of seizures have been developed by agencies in the United Kingdom, Japan, and the International Telecommunications Union, affiliated with the United Nations. The Epilepsy Foundation of America has developed a consensus of medical experts and scientists on this subject, reported in an accompanying work.
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Affiliation(s)
- Robert S Fisher
- Department of Neurology and Neurological Sciences, Stanford Medical Center, Stanford, California 94305-5235, USA.
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Rubboli G, Parra J, Seri S, Takahashi T, Thomas P. EEG Diagnostic Procedures and Special Investigations in the Assessment of Photosensitivity. Epilepsia 2004; 45 Suppl 1:35-9. [PMID: 14706044 DOI: 10.1111/j.0013-9580.2004.451002.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photosensitivity can be assessed in laboratory conditions with different methods. The most common procedure is intermittent photic stimulation (IPS), whose effectiveness in detecting photosensitivity depends largely on methodologic aspects. Although IPS is a widespread and routinely used procedure in EEG laboratories, only recently has a standardization of the IPS method been proposed. Furthermore, other modalities of visual stimulation, including pattern stimulation and low-luminance visual stimulation (LLVS), have proven their usefulness in detecting photosensitivity. We provide an overview of the methodologic aspects and clinical implications of these procedures, resulting from recent consensus meetings, and the diagnostic usefulness of the LLVS technique in photosensitive individuals whose seizures are triggered particularly by television images. Finally, we briefly illustrate the potential of advanced neurophysiological (magnetoencephalography and high-density EEG) and functional imaging techniques in the investigation of the pathophysiologic mechanisms underlying photosensitivity.
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Affiliation(s)
- Guido Rubboli
- Department of Neurological Sciences, University of Bologna, Bellaria Hospital, Bologna, Italy.
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Nagarajan L, Kulkarni A, Palumbo-Clark L, Gregory PB, Walsh PJ, Gubbay SS, Silberstein JM, Silberstein EP, Carty EL, Dimitroff WR. Photoparoxysmal responses in children: their characteristics and clinical correlates. Pediatr Neurol 2003; 29:222-6. [PMID: 14629905 DOI: 10.1016/s0887-8994(03)00207-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study evaluates the characteristics of photoparoxysmal responses elicited with intermittent photic stimulation during a routine electroencephalogram in childhood and correlated this with the clinical profile of the child. Photoparoxysmal responses occurred in 8% (21/263) of children where activation was undertaken. Photoparoxysmal responses were often brief and had a variable onset latency. This study suggests increasing the duration of the stimulus train to 10 seconds or more will increase the diagnostic yield. Photoparoxysmal responses very rarely outlasted the stimulus, and self-limited photoparoxysmal responses probably have greater significance than previously attributed to them. They are highly correlated with epilepsy.
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Affiliation(s)
- Lakshmi Nagarajan
- Department of Neurology, Princess Margaret Hospital for Children, Perth, Australia
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Robinson PA, Rennie CJ, Rowe DL. Dynamics of large-scale brain activity in normal arousal states and epileptic seizures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 65:041924. [PMID: 12005890 DOI: 10.1103/physreve.65.041924] [Citation(s) in RCA: 276] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2001] [Indexed: 05/23/2023]
Abstract
Links between electroencephalograms (EEGs) and underlying aspects of neurophysiology and anatomy are poorly understood. Here a nonlinear continuum model of large-scale brain electrical activity is used to analyze arousal states and their stability and nonlinear dynamics for physiologically realistic parameters. A simple ordered arousal sequence in a reduced parameter space is inferred and found to be consistent with experimentally determined parameters of waking states. Instabilities arise at spectral peaks of the major clinically observed EEG rhythms-mainly slow wave, delta, theta, alpha, and sleep spindle-with each instability zone lying near its most common experimental precursor arousal states in the reduced space. Theta, alpha, and spindle instabilities evolve toward low-dimensional nonlinear limit cycles that correspond closely to EEGs of petit mal seizures for theta instability, and grand mal seizures for the other types. Nonlinear stimulus-induced entrainment and seizures are also seen, EEG spectra and potentials evoked by stimuli are reproduced, and numerous other points of experimental agreement are found. Inverse modeling enables physiological parameters underlying observed EEGs to be determined by a new, noninvasive route. This model thus provides a single, powerful framework for quantitative understanding of a wide variety of brain phenomena.
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Affiliation(s)
- P A Robinson
- Theoretical Physics Group and Center for Wave Physics, School of Physics, University of Sydney, New South Wales 2006, Australia
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Takahashi T, Nakasato N, Yokoyama H, Tsukahara Y. Low-luminance visual stimuli compared with stroboscopic IPS in eliciting PPR in photosensitive patients. Epilepsia 1999; 40 Suppl 4:44-9. [PMID: 10487173 DOI: 10.1111/j.1528-1157.1999.tb00906.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Photosensitivity is thought to play the most important role in the genesis of electronic screen games induced seizures (ESGIS). To elicit photoparoxysmal response (PPR) effectively, we performed EEG activation by low-luminance visual stimuli: 20 cd/m2 deep-red flicker and flickering 2 c/deg geometric pattern stimuli produced by strobofilters. We investigated efficacy of eliciting PPR by use of Grass PS33-plus stroboscopic 18-Hz intermittent photic stimulation (IPS) and low-luminance 18-Hz visual stimuli. METHODS We studied 31 photosensitive patients. We gave stroboscopic IPS (eyes closed and eyes open); after deep-red flicker stimulation (eyes open), we gave flickering geometric-pattern stimuli by using dot, vertical grating, and horizontal grating patterns. RESULTS Stroboscopic IPS elicited PPR in 14 patients, whereas absence of PPR provocation was found in 17 patients. Low-luminance visual stimuli elicited PPR in 30 patients, whereas absence of PPR provocation was found in only one patient. These PPR provocation differences in both stimuli were statistically significant (p < 0.001). CONCLUSIONS The data suggest that low-luminance visual stimuli as described are useful for EEG diagnosis of ESGIS when seizures are thought to be due to photosensitivity.
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Takahashi Y, Fujiwara T, Yagi K, Seino M. Wavelength dependence of photoparoxysmal responses in photosensitive patients with epilepsy. Epilepsia 1999; 40 Suppl 4:23-7. [PMID: 10487169 DOI: 10.1111/j.1528-1157.1999.tb00902.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE We tried to specify the relation between the photoparoxysmal response (PPR) and the wavelength spectra of flashing light in various photosensitive epileptic syndromes in the physiologic state. METHODS Intermittent photic stimulation (IPS) by a Grass PS22 photic stimulator was performed with wavelength-specific optical filters in photosensitive patients with epilepsy (idiopathic generalized epilepsy, IGE; hereditary dentatorubral-pallidoluysian atrophy, DRPLA) and photosensitive subjects without epilepsy. RESULTS Five of 19 normal trichromat patients with IGE and an IGE patient with deuteranomaly showed wavelength-dependent PPRs. The wavelength-dependent PPRs were elicited only by IPS containing wavelength spectra approximately 700 nm in the normal trichromat patients. Two of four patients with DRPLA showed wavelength-dependent PPRs, and two other DRPLA patients showed quantity-of-light-dependent PPRs. Quantity-of-light-dependent PPRs are elicited by IPS containing more than a certain quantity of light, independent of the wavelength composition of the flashing light. Two of five subjects without epilepsy showed wavelength-dependent PPRs. CONCLUSIONS There are wavelength-dependent and quantity-of-light-dependent pathophysiologic mechanisms for eliciting PPRs by low-luminance IPS. Consideration of the quantity and wavelength composition of light from electronic screens will lead to the prevention of photosensitive seizures induced by electronic screen games.
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Affiliation(s)
- Y Takahashi
- National Epilepsy Center, Shizuoka Higashi Hospital, Japan.
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Kasteleijn-Nolst Trenité DG, Binnie CD, Harding GF, Wilkins A. Photic stimulation: standardization of screening methods. Epilepsia 1999; 40 Suppl 4:75-9. [PMID: 10487178 DOI: 10.1111/j.1528-1157.1999.tb00911.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE Differences in methodology of intermittent photic stimulation within and between countries in Europe make collaborative research and interpretation of results difficult. METHOD Experts in the field of photic stimulation from European countries have given an overview of methods used in routine photic stimulation. A consensus meeting was organized in May 1996 in the Netherlands. RESULTS Methodology, including specification of a photo stimulator, procedure of photic stimulation, and interpretation of EEG results, has been defined according to available scientific and clinical knowledge. CONCLUSIONS Consensus was reached in setting up a safe, quick, simple and reliable method to determine whether or not patients are photosensitive. A specification of an international standard for intermittent photic stimulation in the routine EEG examination is given with the purpose of improving patient care and facilitating collaborative research.
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Trenité DG, Binnie CD, Harding GF, Wilkins A, Covanis T, Eeg-Olofsson O, Goosens L, Henriksen O, Krämer G, Leyten F, Da Silva FH, Da Silva AM, Naquet R, Pedersen B, Ricci S, Rubboli G, Spekreijse H, Waltz S. Medical technology assessment photic stimulation--standardization of screening methods. Neurophysiol Clin 1999; 29:318-24. [PMID: 10546250 DOI: 10.1016/s0987-7053(99)90045-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
RATIONALE In many EEG laboratories in Europe, intermittent photic stimulation (IPS) is not performed routinely, and consequently, great variation exists in the type of photo stimulator used, the methodology employed, and the interpretation of the EEG curves, thus leading to different outcomes. METHODOLOGY It was decided to hold a consensus meeting with experts in the field of photic stimulation from various European countries. This meeting was held at the Stichting Epilepsie Instellingen Nederland, Heemstede, the Netherlands. The consensus reached was presented and discussed at the 9th European Congress of Clinical Neurophysiology in Ljubjana in June 1998. RESULTS Patients should be positioned at a distance of 30 cm from the photic stimulator (nasion to lamp) with dim surrounding lights, just enough to see the patient. Flashes should be delivered in separate trains of 10 s for each frequency, with intervals of 7 s minimum. First stimulation occurs with eyes open followed after 5 s by eye closure, while starting at 1 Hz progressing to 20 Hz, unless generalised epileptiform discharges are evoked at a lower frequency. Then, frequencies should start at 60 Hz decreasing to 25 Hz. The following frequencies should be used: 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 60, 50, 40, 30 and 25 Hz. The total duration is a maximum of 6 min (patients without a reaction to IPS). In interpreting the evoked responses, a clear distinction should be made between epileptiform responses confined to the occipital area (OSW), starting occipitally and spreading to frontal regions (OGSW), or generalised from the start (GSW). Other responses include generalised spikes (OR). CONCLUSION This standard is safe, relatively quick, simple and reliable. Comparison of data within patients and between patients of various laboratories will also be possible. This will improve the quality of the care of the individual patient and make collaborative research possible.
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Affiliation(s)
- D G Trenité
- Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands
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