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Sample records for scalp-sphenoidal ictal eeg

  1. Presurgical evaluation for partial epilepsy: Relative contributions of chronic depth-electrode recordings versus FDG-PET and scalp-sphenoidal ictal EEG

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    Engel, J. Jr.; Henry, T.R.; Risinger, M.W.; Mazziotta, J.C.; Sutherling, W.W.; Levesque, M.F.; Phelps, M.E.

    1990-11-01

    One hundred fifty-three patients with medically refractory partial epilepsy underwent chronic stereotactic depth-electrode EEG (SEEG) evaluations after being studied by positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) and scalp-sphenoidal EEG telemetry. We carried out retrospective standardized reviews of local cerebral metabolism and scalp-sphenoidal ictal onsets to determine when SEEG recordings revealed additional useful information. FDG-PET localization was misleading in only 3 patients with temporal lobe SEEG ictal onsets for whom extratemporal or contralateral hypometabolism could be attributed to obvious nonepileptic structural defects. Two patients with predominantly temporal hypometabolism may have had frontal epileptogenic regions, but ultimate localization remains uncertain. Scalp-sphenoidal ictal onsets were misleading in 5 patients. For 37 patients with congruent focal scalp-sphenoidal ictal onsets and temporal hypometabolic zones, SEEG recordings never demonstrated extratemporal or contralateral epileptogenic regions; however, 3 of these patients had nondiagnostic SEEG evaluations. The results of subsequent subdural grid recordings indicated that at least 1 of these patients may have been denied beneficial surgery as a result of an equivocal SEEG evaluation. Weighing risks and benefits, it is concluded that anterior temporal lobectomy is justified without chronic intracranial recording when specific criteria for focal scalp-sphenoidal ictal EEG onsets are met, localized hypometabolism predominantly involves the same temporal lobe, and no other conflicting information has been obtained from additional tests of focal functional deficit, structural imaging, or seizure semiology.

  2. Nonlinear CER Anticipation of Epileptic Seizures is More Effective in Intracranial EEG than in Scalp/Sphenoidal EEG

    Czech Academy of Sciences Publication Activity Database

    Komárek, V.; Hrnčíř, Z.; Paluš, Milan; Procházka, T.; Jiruška, P.; Marusic, P.

    2003-01-01

    Roč. 44, Suppl. 8 (2003), s. 178 ISSN 0013-9580. [International Epilepsy Congress /25./. 12.10.2003-16.10.2003, Lisbon] Institutional research plan: CEZ:AV0Z1030915; MSM 111300003; MSM 111300004 Keywords : brain dynamic * long term EEG analysis Subject RIV: ED - Physiology

  3. Source localization of rhythmic ictal EEG activity

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Lantz, Göran; Rosenzweig, Ivana

    2013-01-01

    Although precise identification of the seizure-onset zone is an essential element of presurgical evaluation, source localization of ictal electroencephalography (EEG) signals has received little attention. The aim of our study was to estimate the accuracy of source localization of rhythmic ictal ...

  4. Canonical decomposition of ictal scalp EEG and accurate source localisation: principles and simulation study.

    Science.gov (United States)

    De Vos, Maarten; De Lathauwer, Lieven; Vanrumste, Bart; Van Huffel, Sabine; Van Paesschen, W

    2007-01-01

    Long-term electroencephalographic (EEG) recordings are important in the presurgical evaluation of refractory partial epilepsy for the delineation of the ictal onset zones. In this paper, we introduce a new concept for an automatic, fast, and objective localisation of the ictal onset zone in ictal EEG recordings. Canonical decomposition of ictal EEG decomposes the EEG in atoms. One or more atoms are related to the seizure activity. A single dipole was then fitted to model the potential distribution of each epileptic atom. In this study, we performed a simulation study in order to estimate the dipole localisation error. Ictal dipole localisation was very accurate, even at low signal-to-noise ratios, was not affected by seizure activity frequency or frequency changes, and was minimally affected by the waveform and depth of the ictal onset zone location. Ictal dipole localisation error using 21 electrodes was around 10.0 mm and improved more than tenfold in the range of 0.5-1.0 mm using 148 channels. In conclusion, our simulation study of canonical decomposition of ictal scalp EEG allowed a robust and accurate localisation of the ictal onset zone.

  5. Scalp EEG Ictal gamma and beta activity during infantile spasms: Evidence of focality.

    Science.gov (United States)

    Nariai, Hiroki; Beal, Jules; Galanopoulou, Aristea S; Mowrey, Wenzhu B; Bickel, Stephan; Sogawa, Yoshimi; Jehle, Rana; Shinnar, Shlomo; Moshé, Solomon L

    2017-05-01

    We investigated temporal and spatial characteristics of ictal gamma and beta activity on scalp EEG during spasms in patients with West syndrome (WS) to evaluate potential focal cortical onset. A total of 1,033 spasms from 34 patients with WS of various etiologies were analyzed on video-electroencephalography (EEG) using time-frequency analysis. Ictal gamma (35-90 Hz) and beta (15-30 Hz) activities were correlated with visual symmetry of spasms, objective EMG (electromyography) analysis, and etiology of WS. Prior to the ictal motor manifestation, focal ictal gamma activity emerged from one hemisphere (71%, 24/34) or from midline (26%, 9/34), and was rarely simultaneously bilateral (3%, 1/34). Focal ictal beta activity emerged from either one hemisphere (68%, 23/34) or from midline (32%, 11/34). Onsets of focal ictal gamma and beta activity were most commonly observed around the parietal areas. Focal ictal gamma activity propagated faster than ictal beta activity to adjacent electrodes (median: 65 vs. 170 msec, p spasms showed asymmetry in peak amplitude and interhemispheric onset latency difference in both ictal gamma and beta activity. Spasms may be a seizure with focal electrographic onset regardless of visual symmetry. Asymmetric involvement of ictal gamma activity to the centroparietal areas may determine the motor manifestations in WS. Scalp EEG ictal gamma and beta activity may be useful to demonstrate localized seizure onset in infants with WS. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

  6. Comparative analysis of MR imaging, Ictal SPECT and EEG in temporal lobe epilepsy: a prospective IAEA multi-center study

    International Nuclear Information System (INIS)

    Zaknun, John J.; Bal, Chandrasekhar; Maes, Alex; Tepmongkol, Supatporn; Vazquez, Silvia; Dupont, Patrick; Dondi, Maurizio

    2008-01-01

    MR imaging, ictal single-photon emission CT (SPECT) and ictal EEG play important roles in the presurgical localization of epileptic foci. This multi-center study was established to investigate whether the complementary role of perfusion SPECT, MRI and EEG for presurgical localization of temporal lobe epilepsy could be confirmed in a prospective setting involving centers from India, Thailand, Italy and Argentina. We studied 74 patients who underwent interictal and ictal EEG, interictal and ictal SPECT and MRI before surgery of the temporal lobe. In all but three patients, histology was reported. The clinical outcome was assessed using Engel's classification. Sensitivity values of all imaging modalities were calculated, and the add-on value of SPECT was assessed. Outcome (Engel's classification) in 74 patients was class I, 89%; class II, 7%; class III, 3%; and IV, 1%. Regarding the localization of seizure origin, sensitivity was 84% for ictal SPECT, 70% for ictal EEG, 86% for MRI, 55% for interictal SPECT and 40% for interictal EEG. Add-on value of ictal SPECT was shown by its ability to correctly localize 17/22 (77%) of the seizure foci missed by ictal EEG and 8/10 (80%) of the seizure foci not detected by MRI. This prospective multi-center trial, involving centers from different parts of the world, confirms that ictal perfusion SPECT is an effective diagnostic modality for correctly identifying seizure origin in temporal lobe epilepsy, providing complementary information to ictal EEG and MRI. (orig.)

  7. Mapping human preictal and ictal haemodynamic networks using simultaneous intracranial EEG-fMRI

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    Umair J. Chaudhary

    2016-01-01

    In conclusion, icEEG-fMRI allowed us to reveal BOLD changes within and beyond the SOZ linked to very localised ictal fluctuations in beta and gamma activity measured in the amygdala and hippocampus. Furthermore, the BOLD changes within the SOZ structures were better captured by the quantitative models, highlighting the interest in considering seizure-related EEG fluctuations across the entire spectrum.

  8. Removing muscle and eye artifacts using blind source separation techniques in ictal EEG source imaging.

    Science.gov (United States)

    Hallez, H; De Vos, M; Vanrumste, B; Van Hese, P; Assecondi, S; Van Laere, K; Dupont, P; Van Paesschen, W; Van Huffel, S; Lemahieu, I

    2009-07-01

    The contamination of muscle and eye artifacts during an ictal period of the EEG significantly distorts source estimation algorithms. Recent blind source separation (BSS) techniques based on canonical correlation (BSS-CCA) and independent component analysis with spatial constraints (SCICA) have shown much promise in the removal of these artifacts. In this study we want to use BSS-CCA and SCICA as a preprocessing step before the source estimation during the ictal period. Both the contaminated and cleaned ictal EEG were subjected to the RAP-MUSIC algorithm. This is a multiple dipole source estimation technique based on the separation of the EEG in signal and noise subspace. The source estimates were compared with the subtracted ictal SPECT (iSPECT) coregistered to magnetic resonance imaging (SISCOM) by means of the euclidean distance between the iSPECT activations and the dipole location estimates. SISCOM results in an image denoting the ictal onset zone with a propagation. We applied the artifact removal and the source estimation on 8 patients. Qualitatively, we can see that 5 out of 8 patients show an improvement of the dipoles. The dipoles are nearer to or have tighter clusters near the iSPECT activation. From the median of the distance measure, we could appreciate that 5 out of 8 patients show improvement. The results show that BSS-CCA and SCICA can be applied to remove artifacts, but the results should be interpreted with care. The results of the source estimation can be misleading due to excessive noise or modeling errors. Therefore, the accuracy of the source estimation can be increased by preprocessing the ictal EEG segment by BSS-CCA and SCICA. This is a pilot study where EEG source localization in the presurgical evaluation can be made more reliable, if preprocessing techniques such as BSS-CCA and SCICA are used prior to EEG source analysis on ictal episodes.

  9. Effects of Marijuana on Ictal and Interictal EEG Activities in Idiopathic Generalized Epilepsy.

    Science.gov (United States)

    Sivakumar, Sanjeev; Zutshi, Deepti; Seraji-Bozorgzad, Navid; Shah, Aashit K

    2017-01-01

    Marijuana-based treatment for refractory epilepsy shows promise in surveys, case series, and clinical trials. However, literature on their EEG effects is sparse. Our objective is to analyze the effect of marijuana on EEG in a 24-year-old patient with idiopathic generalized epilepsy treated with cannabis. We blindly reviewed 3 long-term EEGs-a 24-hour study while only on antiepileptic drugs, a 72-hour EEG with Cannabis indica smoked on days 1 and 3 in addition to antiepileptic drugs, and a 48-hour EEG with combination C indica/sativa smoked on day 1 plus antiepileptic drugs. Generalized spike-wave discharges and diffuse paroxysmal fast activity were categorized as interictal and ictal, based on duration of less than 10 seconds or greater, respectively. Data from three studies concatenated into contiguous time series, with usage of marijuana modeled as time-dependent discrete variable while interictal and ictal events constituted dependent variables. Analysis of variance as initial test for significance followed by time series analysis using Generalized Autoregressive Conditional Heteroscedasticity model was performed. Statistical significance for lower interictal events (analysis of variance P = 0.001) was seen during C indica use, but not for C indica/sativa mixture (P = 0.629) or ictal events (P = 0.087). However, time series analysis revealed a significant inverse correlation between marijuana use, with interictal (P < 0.0004) and ictal (P = 0.002) event rates. Using a novel approach to EEG data, we demonstrate a decrease in interictal and ictal electrographic events during marijuana use. Larger samples of patients and EEG, with standardized cannabinoid formulation and dosing, are needed to validate our findings.

  10. Ictal time-irreversible intracranial EEG signals as markers of the epileptogenic zone.

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    Schindler, Kaspar; Rummel, Christian; Andrzejak, Ralph G; Goodfellow, Marc; Zubler, Frédéric; Abela, Eugenio; Wiest, Roland; Pollo, Claudio; Steimer, Andreas; Gast, Heidemarie

    2016-09-01

    To show that time-irreversible EEG signals recorded with intracranial electrodes during seizures can serve as markers of the epileptogenic zone. We use the recently developed method of mapping time series into directed horizontal graphs (dHVG). Each node of the dHVG represents a time point in the original intracranial EEG (iEEG) signal. Statistically significant differences between the distributions of the nodes' number of input and output connections are used to detect time-irreversible iEEG signals. In 31 of 32 seizure recordings we found time-irreversible iEEG signals. The maximally time-irreversible signals always occurred during seizures, with highest probability in the middle of the first seizure half. These signals spanned a large range of frequencies and amplitudes but were all characterized by saw-tooth like shaped components. Brain regions removed from patients who became post-surgically seizure-free generated significantly larger time-irreversibilities than regions removed from patients who still had seizures after surgery. Our results corroborate that ictal time-irreversible iEEG signals can indeed serve as markers of the epileptogenic zone and can be efficiently detected and quantified in a time-resolved manner by dHVG based methods. Ictal time-irreversible EEG signals can help to improve pre-surgical evaluation in patients suffering from pharmaco-resistant epilepsies. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  11. Denoising of Ictal EEG Data Using Semi-Blind Source Separation Methods Based on Time-Frequency Priors.

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    Hajipour Sardouie, Sepideh; Bagher Shamsollahi, Mohammad; Albera, Laurent; Merlet, Isabelle

    2015-05-01

    Removing muscle activity from ictal ElectroEncephaloGram (EEG) data is an essential preprocessing step in diagnosis and study of epileptic disorders. Indeed, at the very beginning of seizures, ictal EEG has a low amplitude and its morphology in the time domain is quite similar to muscular activity. Contrary to the time domain, ictal signals have specific characteristics in the time-frequency domain. In this paper, we use the time-frequency signature of ictal discharges as a priori information on the sources of interest. To extract the time-frequency signature of ictal sources, we use the Canonical Correlation Analysis (CCA) method. Then, we propose two time-frequency based semi-blind source separation approaches, namely the Time-Frequency-Generalized EigenValue Decomposition (TF-GEVD) and the Time-Frequency-Denoising Source Separation (TF-DSS), for the denoising of ictal signals based on these time-frequency signatures. The performance of the proposed methods is compared with that of CCA and Independent Component Analysis (ICA) approaches for the denoising of simulated ictal EEGs and of real ictal data. The results show the superiority of the proposed methods in comparison with CCA and ICA.

  12. Do ictal EEG characteristics predict treatment outcomes in schizophrenic patients undergoing electroconvulsive therapy?

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    Simsek, Gulnihal Gokce; Zincir, Selma; Gulec, Huseyin; Eksioglu, Sevgin; Semiz, Umit Basar; Kurtulmus, Yasemin Sipka

    2015-08-01

    The aim of this study is to investigate the relationship between features of electroencephalography (EEG), including seizure time, energy threshold level and post-ictal suppression time, and clinical variables, including treatment outcomes and side-effects, among schizophrenia inpatients undergoing electroconvulsive therapy (ECT). This is a naturalistic follow-up study on schizophrenia patients, diagnosed using DSM-IV-TR criteria, treated by a psychosis inpatient service. All participants completed the Brief Psychiatric Rating Scale (BPRS), the Global Assessment of Functioning (GAF) scale, the Frontal Assessment Battery (FAB) and a Data Collection Form. Assessments were made before treatment, during ECT and after treatment. Statistically significant improvements in both clinical and cognitive outcome were noted after ECT in all patients. Predictors of improvement were sought by evaluating electrophysiological variables measured at three time points (after the third, fifth and seventh ECT sessions). Logistic regression analysis showed that clinical outcome/improvement did not differ by seizure duration, threshold energy level or post-ictal suppression time. We found that ictal EEG parameters measured at several ECT sessions did not predict clinical recovery/outcomes. This may be because our centre defensively engages in "very specific patient selection" when ECT is contemplated. ECT does not cause short-term cognitive functional impairment and indeed improves cognition, because symptoms of the schizophrenic episode are alleviated.

  13. Correlation between temporal pole MRI abnormalities and surface ictal EEG patterns in patients with unilateral mesial temporal lobe epilepsy.

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    Caboclo, Luís Otávio S F; Garzon, Eliana; Oliveira, Pedro A L; Carrete, Henrique; Centeno, Ricardo S; Bianchin, Marino M; Yacubian, Elza Márcia T; Sakamoto, Américo C

    2007-01-01

    The objective of this retrospective study is to analyze ictal patterns observed during continuous Video-EEG monitoring in patients with temporal lobe epilepsy (TLE) due to unilateral hippocampal sclerosis (HS), and to correlate these EEG patterns to temporal pole abnormalities observed on magnetic resonance imaging exams. We analyzed 147 seizures from 35 patients with TLE and unilateral HS. Ictal patterns were classified and correlated to signal abnormalities and volumetric measures of the temporal poles. Volume differences over 10% were considered abnormal. The most frequent type of ictal pattern was rhythmic theta activity (RTA), encountered in 65.5% of the seizures. Rhythmic beta activity (RBA) was observed in 11% of the seizures, localized attenuation in 8%, interruption of epileptiform discharges in 6%, repetitive discharges in 5.5%, and rhythmic delta activity (RDA) in 4%. Sixty-six percent of the patients presented signal abnormalities in the temporal pole that were always ipsilateral to the HS. Sixty percent presented significant asymmetry of the temporal poles consisting of reduced volume that was also always ipsilateral to HS. Although patients with RTA as the predominant ictal pattern tended to present asymmetry of temporal poles (p=0.305), the ictal EEG pattern did not correlate with temporal pole asymmetry or signal abnormalities. RTA is the most frequent initial ictal pattern in patients with TLE due to unilateral HS. Temporal pole signal changes and volumetric reduction were commonly found in this group of patients, both abnormalities appearing always ipsilateral to the HS. However, neither temporal pole volume reduction nor signal abnormalities correlated with the predominant ictal pattern, suggesting that the temporal poles are not crucially involved in the process of epileptogenesis.

  14. SCOPE-mTL: A non-invasive tool for identifying and lateralizing mesial temporal lobe seizures prior to scalp EEG ictal onset.

    Science.gov (United States)

    Lam, Alice D; Maus, Douglas; Zafar, Sahar F; Cole, Andrew J; Cash, Sydney S

    2017-09-01

    In mesial temporal lobe (mTL) epilepsy, seizure onset can precede the appearance of a scalp EEG ictal pattern by many seconds. The ability to identify this early, occult mTL seizure activity could improve lateralization and localization of mTL seizures on scalp EEG. Using scalp EEG spectral features and machine learning approaches on a dataset of combined scalp EEG and foramen ovale electrode recordings in patients with mTL epilepsy, we developed an algorithm, SCOPE-mTL, to detect and lateralize early, occult mTL seizure activity, prior to the appearance of a scalp EEG ictal pattern. Using SCOPE-mTL, 73% of seizures with occult mTL onset were identified as such, and no seizures that lacked an occult mTL onset were identified as having one. Predicted mTL seizure onset times were highly correlated with actual mTL seizure onset times (r=0.69). 50% of seizures with early mTL onset were lateralizable prior to scalp ictal onset, with 94% accuracy. SCOPE-mTL can identify and lateralize mTL seizures prior to scalp EEG ictal onset, with high sensitivity, specificity, and accuracy. Quantitative analysis of scalp EEG can provide important information about mTL seizures, even in the absence of a visible scalp EEG ictal correlate. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  15. Ictal Symmetric Tonic Extension Posturing and Postictal Generalized EEG Suppression Arising From Sleep in Children With Epilepsy.

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    Okanari, Kazuo; Otsubo, Hiroshi; Kouzmitcheva, Elizabeth; Rangrej, Jagadish; Baba, Shiro; Ochi, Ayako; Okanishi, Tohru; Homma, Yoichiro; Nita, Dragos A; Donner, Elizabeth J

    2017-11-01

    The identification of a biomarker for sudden unexpected death in epilepsy (SUDEP) has the potential to save lives. Generalized convulsive seizures and postictal generalized suppression on electroencephalography (EEG) most often precede sudden unexpected death in epilepsy (SUDEP) and are potential biomarkers. We identify the EEG and seizure characteristics associated with postictal generalized EEG suppression in children with epilepsy. Video EEGs were reviewed for seizure type, duration and semiology, and electrographic features. To identify predictors of postictal generalized EEG suppression, we identified 40 children with generalized convulsive seizures from a group of 399 patients who experienced an electroclinical seizure during video-EEG. Seventy-seven generalized convulsive seizures with and without postictal generalized EEG suppression were anayzed. Age of seizure onset was older in 19 children with postictal generalized EEG suppression (mean 6.8 years old, 95% CI [4.7-8.9]) than in 21 without postictal generalized EEG suppression (3.0 years old, [1.1-4.1], P = 0.041). Postictal generalized EEG suppression occurred significantly more often from sleep than awake (point of estimate 16.67; 95% CI [0.97-32.36], P < 0.038). Shorter duration of the clonic phase (-0.76; [-1.338, -0.133], P = 0.018) was significantly associated with postictal generalized EEG suppression. Ictal symmetric tonic extension posturing significantly increased the odds of postictal generalized EEG suppression (42.94; [18.77, 67.12], P = 0.001). All 15 generalized convulsive seizures with a terminal burst-suppression pattern were followed by postictal generalized EEG suppression in contrast to 19 of 62 generalized convulsive seizures without burst-suppression (15.32, P < 0.001). Ictal decerebrate-like symmetric tonic extension posturing with shorter clonic phase and a terminal burst-suppression pattern identify malignant generalized convulsive seizures, associated with postictal

  16. Fast (40-150Hz) oscillations are associated with positive slow waves in the ictal EEGs of epileptic spasms in West syndrome.

    Science.gov (United States)

    Kobayashi, Katsuhiro; Akiyama, Tomoyuki; Oka, Makio; Endoh, Fumika; Yoshinaga, Harumi

    2016-11-01

    To elucidate the generative mechanisms of epileptic spasms (ESs) in West syndrome, we investigated the temporal relationship between scalp fast (40-150Hz) oscillations (FOs) and slow waves in the ictal electroencephalograms (EEGs) of ESs. In 11 infants with WS, ictal FOs were detected in a bipolar montage based on spectral and waveform criteria. Their temporal distribution was analyzed in terms of the positive peaks (trough point, T T ) of identical EEG data in a referential montage. Among six EEG data sections defined according to T T , the number of FOs, peak power values, and peak frequencies were compared. We identified a total of 1014 FOs (946 gamma and 68 ripple oscillations), which clustered closely at T T . The number of gamma oscillations in the 1s epoch including T T was significantly higher than those in the prior and subsequent phases. Peak power values and frequencies tended to be higher in these positive phase sections. The temporal association of FO clustering and positive slow waves in the ictal EEGs of ES indicated that active neuronal firing related to FOs underlies the generation of ESs and their ictal slow waves. Copyright © 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  17. The Performance of Ictal Brain SPECT Localizing for Epileptogenic Zone in Neocortical Epilepsy

    International Nuclear Information System (INIS)

    Kim, Eun Sik; Lee, Dong Soo; Hyun, In Young; Chung, June Key; Lee, Myung Chul; Koh, Chang Soon; Lee, Sang Kun; Chang, Kee Hyun

    1995-01-01

    The epileptogenic zones should be localized precisely before surgical resection of these zones in intractable epilepsy. The localization is more difficult in patients with neocortical epilepsy than in patients with temporal lobe epilepsy. This study aimed at evaluation of the usefulness of ictal brain perfusion SPECT for the localization of epileptogenic zones in neocortical epilepsy. We compared the performance of ictal SPECT with MRI referring to ictal scalp electroencephalography (sEEG). Ictal 99m Tc-HMPAO SPECT were done in twenty-one patients. Ictal EEG were also obtained during video monitoring. MRI were reviewed. According to the ictal sEEG and semiology, 8 patients were frontal lobe epilepsy, 7 patients were lateral temporal lobe epilepsy, 2 patients were parietal lobe epilepsy, and 4 patients were occipital lobe epilepsy. Ictal SPECT showed hyperperfusion in 14 patients(67%) in the zones which were suspected to be epileptogenic according to ictal EEG and semiology. MRI found morphologic abnormalities in 9 patients(43%). Among the 12 patients, in whom no epileptogenic zones were revealed by MR1, ictal SPECT found zones of hyperperfusion concordant with ictal sEEG in 9 patients(75%). However, no zones of hyperperfusion were found in 4 among 9 patients who were found to have cerebromalacia, abnormal calcification and migration anomaly in MRI. We thought that ictal SPECT was useful for localization of epileptogenic zones in neocortical epilepsy and especially in patients with negative findings in MRI.

  18. The Performance of Ictal Brain SPECT Localizing for Epileptogenic Zone in Neocortical Epilepsy

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    Kim, Eun Sik; Lee, Dong Soo; Hyun, In Young; Chung, June Key; Lee, Myung Chul; Koh, Chang Soon; Lee, Sang Kun; Chang, Kee Hyun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1995-09-15

    The epileptogenic zones should be localized precisely before surgical resection of these zones in intractable epilepsy. The localization is more difficult in patients with neocortical epilepsy than in patients with temporal lobe epilepsy. This study aimed at evaluation of the usefulness of ictal brain perfusion SPECT for the localization of epileptogenic zones in neocortical epilepsy. We compared the performance of ictal SPECT with MRI referring to ictal scalp electroencephalography (sEEG). Ictal {sup 99m}Tc-HMPAO SPECT were done in twenty-one patients. Ictal EEG were also obtained during video monitoring. MRI were reviewed. According to the ictal sEEG and semiology, 8 patients were frontal lobe epilepsy, 7 patients were lateral temporal lobe epilepsy, 2 patients were parietal lobe epilepsy, and 4 patients were occipital lobe epilepsy. Ictal SPECT showed hyperperfusion in 14 patients(67%) in the zones which were suspected to be epileptogenic according to ictal EEG and semiology. MRI found morphologic abnormalities in 9 patients(43%). Among the 12 patients, in whom no epileptogenic zones were revealed by MR1, ictal SPECT found zones of hyperperfusion concordant with ictal sEEG in 9 patients(75%). However, no zones of hyperperfusion were found in 4 among 9 patients who were found to have cerebromalacia, abnormal calcification and migration anomaly in MRI. We thought that ictal SPECT was useful for localization of epileptogenic zones in neocortical epilepsy and especially in patients with negative findings in MRI.

  19. Maternal care affects EEG properties of spike-wave seizures (including pre- and post ictal periods) in adult WAG/Rij rats with genetic predisposition to absence epilepsy.

    Science.gov (United States)

    Sitnikova, Evgenia; Rutskova, Elizaveta M; Raevsky, Vladimir V

    2016-10-01

    WAG/Rij rats have a genetic predisposition to absence epilepsy and develop spontaneous spike-wave discharges in EEG during late ontogenesis (SWD, EEG manifestation of absence epilepsy). Changes in an environment during early postnatal ontogenesis can influence the genetically predetermined absence epilepsy. Here we examined the effect of maternal environment during weaning period on the EEG manifestation of absence epilepsy in adulthood. Experiments were performed in the offspring of WAG/Rij and Wistar rats. The newborn pups were fostered to dams of the same (in-fostering) or another strain (cross-fostering). Age-matched control WAG/Rij and Wistar rats were reared by their biological mothers. Absence seizures were uncommon in Wistar and were not aggravated in both in- and cross-fostered groups. In WAG/Rij rats, fewer SWD were found in the cross-fostered as compared to the in-fostered group. The cross-fostered WAG/Rij rats showed higher percentage of short-lasting SWD with duration <2s. The mean frequency of EEG at the beginning of SWD in the cross-fostered WAG/Rij rats was lower than in control (8.82 vs 9.25Hz), but it was higher in a period of 1.5s before and after SWD. It was concluded that a healthier maternal environment is able to alleviate genetically predetermined absence seizures in adulthood through changes in EEG rhythmic activity. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Ictus emeticus (ictal vomiting).

    Science.gov (United States)

    Shuper, Avinoam; Goldberg-Stern, Hadassa

    2004-10-01

    Vomiting is rarely the main ictal manifestation of epilepsy, and it is likely associated with more than one type of epilepsy. Its possible mechanism involves the spread of abnormal electrical activity through descending insular or limbic circuits. This report describes a child with difficult-to-control ictal vomiting arising from a left temporal epileptic focus. Ictus emeticus is a specific epileptic presentation which can have a chronic, intractable nature requiring repetitive therapeutic trials with antiepileptic medications. In the patient described here, the disease posed a diagnostic dilemma in its early stages. The ictal electroencephalogram is crucial for the diagnosis.

  1. Ictal source imaging and electroclinical correlation in self-limited epilepsy with centrotemporal spikes

    DEFF Research Database (Denmark)

    Alving, Jørgen; Fabricius, Martin; Rosenzweig, Ivana

    2017-01-01

    PURPOSE: To elucidate the localization of ictal EEG activity, and correlate it to semiological features in self-limited epilepsy with centrotemporal spikes (formerly called "benign epilepsy with centrotemporal spikes"). METHODS: We have performed ictal electric source imaging, and we analysed...

  2. Ictal Ceretec studies - the Austin experience

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    Nerouppos, L.; Scott, A.M.; Parsons, K.; Mihalinac, D.S.; Munoz, P.; McKay, W.J. [Austin Hospital , Heidelberg, VIC (Australia). Departments of Nuclear Medicine and Neurology

    1998-06-01

    Full text: Ictal Ceretec studies play a major role in the patient work-up for surgery of focal epilepsy in the Comprehensive Epilepsy Program at the Austin Hospital. The validity of ictal Ceretec and the superior sensitivity of this technique for the detection of epileptic foci over post-ictal and inter-ictal studies are well documented. Over the past eight years our experience and close collaboration with the Comprehensive Epilepsy Program has led to the implementation of a streamlined program enabling ictal Ceretec to be performed on numerous patients. The patients on this program since October 1991 will be reviewed and quality assurance (QA) results will be addressed. Ceretec is stored in a special lead-lined container in the video monitoring rooms, together with a shielded syringe of freshly eluted pre-calibrated technetium. Once a seizure is detected, the medical staff prepare the Ceretec and inject the required volume, obtained from the pre-calibration sheet, through a previously inserted in-dwelling line. The ward staff record the time of injection, the estimated duration of the seizure, the clinical impression of the seizure and the suspected focus. The injection tray is brought to the department within thirty minutes, where the patient injected dose is determined and quality control is performed. The scan is performed on a triple-headed Trionix gamma camera and reported once EEG and video recordings obtained during the ictus confirm the nature of the seizure. The advantages of this program are numerous. Many modifications have been made to the program over the past three years, due to close inspection of the QA forms. Ward and nuclear medicine staff deal with problems promptly, ensuring an effective and efficient program

  3. EEG

    African Journals Online (AJOL)

    2017-09-03

    Sep 3, 2017 ... In clinical psychiatry, EEG is also used in evaluating pres- ence of seizure especially the ones that produce complex behaviors (temporal lobe, frontal lobe and petit mal sei- zures). EEG can also be used during electroconvulsive therapy (ECT) to monitor whether or not the stimulus produces seizure activity.

  4. EEG

    Science.gov (United States)

    ... is also used to: Evaluate problems with sleep ( sleep disorders ) Monitor the brain during brain surgery An EEG may be done ... in some cases) Seizure disorder (such as epilepsy) Sleep disorder (such as narcolepsy ) Swelling of the brain (edema) Risks An EEG test is very safe. ...

  5. Ictal asystole and ictal syncope: insights into clinical management.

    Science.gov (United States)

    Bestawros, Michael; Darbar, Dawood; Arain, Amir; Abou-Khalil, Bassel; Plummer, Dale; Dupont, William D; Raj, Satish R

    2015-02-01

    Ictal asystole is a rare, serious, and often treatable cause of syncope. There are currently limited data to guide management. Characterization of ictal syncope predictors may aid in the selection of high-risk patients for treatments such as pacemakers. We searched our epilepsy monitoring unit database from October 2003 to July 2013 for all patients with ictal asystole events. Clinical, electroencephalogram, and ECG data for each of their seizures were examined for their relationships with ictal syncope events. In 10 patients with ictal asystole, we observed 76 clinical seizures with 26 ictal asystole episodes, 15 of which led to syncope. No seizure with asystole duration≤6 s led to syncope, whereas 94% (15/16) of seizures with asystole duration>6 s led to syncope (P=0.02). During ictal asystole events, 4 patients had left temporal seizure onset, 4 patients had right temporal seizure onset, and 2 patients had both. Syncope was more common with left temporal (40%) than with right temporal seizures (10%; P=0.002). Treatment options included antiepileptic drug changes, epilepsy surgery, and pacemaker implantation. Eight patients received pacemakers. During follow-up of 72±95 months, all patients remained syncope free. Ictal asystole>6 s is strongly associated with ictal syncope. Ictal syncope is more common in left than in right temporal seizures. A permanent pacemaker should be considered in patients with ictal syncope if they are not considered good candidates for epilepsy surgery. © 2014 American Heart Association, Inc.

  6. Resection of ictal high-frequency oscillations leads to favorable surgical outcome in pediatric epilepsy

    Science.gov (United States)

    Fujiwara, Hisako; Greiner, Hansel M.; Lee, Ki Hyeong; Holland-Bouley, Katherine D.; Seo, Joo Hee; Arthur, Todd; Mangano, Francesco T.; Leach, James L.; Rose, Douglas F.

    2012-01-01

    Summary Purpose Intracranial electroencephalography (EEG) is performed as part of an epilepsy surgery evaluation when noninvasive tests are incongruent or the putative seizure-onset zone is near eloquent cortex. Determining the seizure-onset zone using intracranial EEG has been conventionally based on identification of specific ictal patterns with visual inspection. High-frequency oscillations (HFOs, >80 Hz) have been recognized recently as highly correlated with the epileptogenic zone. However, HFOs can be difficult to detect because of their low amplitude. Therefore, the prevalence of ictal HFOs and their role in localization of epileptogenic zone on intracranial EEG are unknown. Methods We identified 48 patients who underwent surgical treatment after the surgical evaluation with intracranial EEG, and 44 patients met criteria for this retrospective study. Results were not used in surgical decision making. Intracranial EEG recordings were collected with a sampling rate of 2,000 Hz. Recordings were first inspected visually to determine ictal onset and then analyzed further with time-frequency analysis. Forty-one (93%) of 44 patients had ictal HFOs determined with time-frequency analysis of intracranial EEG. Key Findings Twenty-two (54%) of the 41 patients with ictal HFOs had complete resection of HFO regions, regardless of frequency bands. Complete resection of HFOs (n = 22) resulted in a seizure-free outcome in 18 (82%) of 22 patients, significantly higher than the seizure-free outcome with incomplete HFO resection (4/19, 21%). Significance Our study shows that ictal HFOs are commonly found with intracranial EEG in our population largely of children with cortical dysplasia, and have localizing value. The use of ictal HFOs may add more promising information compared to interictal HFOs because of the evidence of ictal propagation and followed by clinical aspect of seizures. Complete resection of HFOs is a favorable prognostic indicator for surgical outcome. PMID

  7. Ictal SPECT using an attachable automated injector: clinical usefulness in the prediction of ictal onset zone.

    Science.gov (United States)

    Lee, Jung-Ju; Lee, Sang Kun; Choi, Jang Wuk; Kim, Dong-Wook; Park, Kyung Il; Kim, Bom Sahn; Kang, Hyejin; Lee, Dong Soo; Lee, Seo-Young; Kim, Sung Hun; Chung, Chun Kee; Nam, Hyeon Woo; Kim, Kwang Ki

    2009-12-01

    Ictal single-photon emission computed tomography (SPECT) is a valuable method for localizing the ictal onset zone in the presurgical evaluation of patients with intractable epilepsy. Conventional methods used to localize the ictal onset zone have problems with time lag from seizure onset to injection. To evaluate the clinical usefulness of a method that we developed, which involves an attachable automated injector (AAI), in reducing time lag and improving the ability to localize the zone of seizure onset. Patients admitted to the epilepsy monitoring unit (EMU) between January 1, 2003, and June 30, 2008, were included. The definition of ictal onset zone was made by comprehensive review of medical records, magnetic resonance imaging (MRI), data from video electroencephalography (EEG) monitoring, and invasive EEG monitoring if available. We comprehensively evaluated the time lag to injection and the image patterns of ictal SPECT using traditional visual analysis, statistical parametric mapping-assisted, and subtraction ictal SPECT coregistered to an MRI-assisted means of analysis. Image patterns were classified as localizing, lateralizing, and nonlateralizing. The whole number of patients was 99: 48 in the conventional group and 51 in the AAI group. The mean (SD) delay time to injection from seizure onset was 12.4+/-12.0 s in the group injected by our AAI method and 40.4+/-26.3 s in the group injected by the conventional method (P=0.000). The mean delay time to injection from seizure detection was 3.2+/-2.5 s in the group injected by the AAI method and 21.4+/-9.7 s in the group injected by the conventional method (P=0.000). The AAI method was superior to the conventional method in localizing the area of seizure onset (36 out of 51 with AAI method vs. 21 out of 48 with conventional method, P=0.009), especially in non-temporal lobe epilepsy (non-TLE) patients (17 out of 27 with AAI method vs. 3 out of 13 with conventional method, P=0.041), and in lateralizing the

  8. Topographic movie of intracranial ictal high-frequency oscillations with seizure semiology: epileptic network in Jacksonian seizures.

    Science.gov (United States)

    Akiyama, Tomoyuki; Chan, Derrick W; Go, Cristina Y; Ochi, Ayako; Elliott, Irene M; Donner, Elizabeth J; Weiss, Shelly K; Snead, O Carter; Rutka, James T; Drake, James M; Otsubo, Hiroshi

    2011-01-01

    We developed a technique to produce images of dynamic changes in ictal high-frequency oscillations (HFOs) >40 Hz recorded on subdural electroencephalography (EEG) that are time-locked to the ictal EEG and ictal semiology video. We applied this technique to Jacksonian seizures to demonstrate ictal HFO propagation along the homunculus in the primary sensory-motor cortex to visualize the underlying epileptic network. We analyzed intracranial ictal EEGs from two patients with intractable Jacksonian seizures who underwent epilepsy surgery. We calculated the degrees of increase in amplitude within 40-80, 80-200, and 200-300 Hz frequency bands compared to the interictal period and converted them into topographic movies projected onto the brain surface picture. We combined these data with the ictal EEGs and video of the patient demonstrating ictal semiology. The ictal HFOs began in the sensory cortex and appeared concomitantly with the sensory aura. They then propagated to the motor cortex at the same time that focal motor symptoms evolved. As the seizure progressed, the ictal HFOs spread or reverberated in the rolandic region. However, even when the seizure became secondarily generalized, the ictal HFOs were confined to the rolandic region. In both cases, there was increased amplitude of higher frequency bands during seizure initiation compared to seizure progression. This combined movie showed the ictal HFO propagation corresponding to the ictal semiology in Jacksonian seizures and revealed the epileptic network involved in seizure initiation and progression. This method may advance understanding of neural network activities relating to clinical seizure generation and propagation. Wiley Periodicals, Inc. © 2010 International League Against Epilepsy.

  9. Dynamic statistical parametric mapping for analyzing ictal magnetoencephalographic spikes in patients with intractable frontal lobe epilepsy.

    Science.gov (United States)

    Tanaka, Naoaki; Cole, Andrew J; von Pechmann, Deidre; Wakeman, Daniel G; Hämäläinen, Matti S; Liu, Hesheng; Madsen, Joseph R; Bourgeois, Blaise F; Stufflebeam, Steven M

    2009-08-01

    The purpose of this study is to assess the clinical value of spatiotemporal source analysis for analyzing ictal magnetoencephalography (MEG). Ictal MEG and simultaneous scalp EEG was recorded in five patients with medically intractable frontal lobe epilepsy. Dynamic statistical parametric maps (dSPMs) were calculated at the peak of early ictal spikes for the purpose of estimating the spatiotemporal cortical source distribution. DSPM solutions were mapped onto a cortical surface, which was derived from each patient's MRI. Equivalent current dipoles (ECDs) were calculated using a single-dipole model for comparison with dSPMs. In all patients, dSPMs tended to have a localized activation, consistent with the clinically determined ictal onset zone, whereas most ECDs were considered to be inappropriate sources according to their goodness-of-fit values. Analyzing ictal MEG spikes by using dSPMs may provide useful information in presurgical evaluation of epilepsy.

  10. Ictal and interictal SPECT imaging of 8 patients with symptomatic partial epilepsy

    International Nuclear Information System (INIS)

    Motooka, Hiromichi

    1993-01-01

    Although epileptic discharges such as spike, spike and wave complex, sharp wave, and sharp and wave complex can be recorded by interictal scalp electroencephalography (EEG) in many patients with epilepsy, recent studies have demonstrated that no epileptic discharges can be recorded by interictal and ictal scalp EEGs in some patients who clinically exhibit epileptic seizures. Accordingly scalp EEG is not always helpful for diagnosing epilepsy or identifying the epileptic foci in the brain in these patients. Recently, studies using single photon emission computed tomography (SPECT) have been performed for patients with epilepsy and evidence that epileptic foci can be identified by changes in the regional cerebral blood flow (rCBF) seen on SPECT scanning have been accumulated. In the present study, therefore, 8 patients with medically intractable partial seizures were simultaneously or independently investigated by the recordings of scalp EEG and SPECT scanning during the interictal and ictal period. N-isopropyl-p[ 123 I]-iodoamphetamine ( 123 I-IMP) was used for SPECT scanning for 7 patients and 99m Tc-d,l-hexamethyl-propyleneamineoxime ( 99m Tc-HMPAO) for 1 patient. An increase in rCBF (hyperperfusion) or decrease in rCBF (hypoperfusion) were found in 4 patients by interictal SPECT imaging and in all patients by ictal SPECT imaging although epileptic discharges were observed in 3 patients by interictal scalp EEG and 5 patients by ictal scalp EEG. The findings of the present study indicate that ictal SPECT scanning is more useful for diagnosing epilepsy and identifying the epileptic foci in the brain than ictal scalp EEG. (author)

  11. Ictal asystole in temporal lobe epilepsy before and after pacemaker implantation.

    Science.gov (United States)

    Strzelczyk, Adam; Bauer, Sebastian; Knake, Susanne; Oertel, Wolfgang H; Hamer, Hajo M; Rosenow, Felix

    2008-03-01

    Events of ictal bradycardia or asystole may be of relevance in epilepsy patients presenting with ictal falls, and are a potential contributor to SUDEP. The literature on ictal bradycardia or asystole is anecdotal and consists of case reports and small case series. There are no guidelines for the care of patients with ictal arrhythmias. Insertion of cardiac pacemakers may prevent life-threatening cardiac arrest, syncope and trauma. We report the case of a 41-year-old man who presented with refractory partial seizures resulting in syncope leading to severe head trauma, as the only ictal semiology. During presurgical video-EEG monitoring, two episodes of ictal bradycardia followed by asystole and syncope were recorded. A cardiac pacemaker was implanted. At the nine-month follow-up, the patient reported no overt seizures, syncopes or traumatic falls. Our case demonstrates that implantation of a cardiac pacemaker while continuing AEDs may render a patient free from ictal symptoms and prevent ictal syncope and subsequent trauma. [Published with video sequences].

  12. Ictal SPECT in neocortical epilepsies: clinical usefulness and factors affecting the pattern of hyperperfusion

    International Nuclear Information System (INIS)

    Lee, Sang Kun; Lee, Seo-Young; Yun, Chang-Ho; Lee, Ho-Young; Lee, Jae-Sung; Lee, Dong-Soo

    2006-01-01

    The aims of this analysis were to: (1) determine the value of ictal SPECT in the localization of neocortical epileptogenic foci, (2) evaluate the relationships between the results of ictal SPECT and other potential affecting factors, and (3) compare traditional visual analysis and the subtraction method. We retrospectively analyzed 81 consecutive patients with neocortical epilepsy who underwent epilepsy surgery and achieved a favourable surgical outcome, including 36 patients with normal MRI. Side-by-side visual analysis and subtraction images were classified as correctly localizing,correctly lateralizing, or non-localizing/non-lateralizing images according to the resected lobe. Side-by-side visual analysis and subtraction SPECT correctly localized the epileptogenic lobe in 58.9% and 63.0% of patients, respectively. The two methods were complementary and the diagnostic sensitivity of ictal SPECT using the two methods was 79.0%. Ictal SPECT using the visual method correctly localized the epileptogenic lobe more frequently in patients with a localizing pattern of ictal scalp EEG at the time of radioligand injection. When using subtraction images, an injection delay of less than 20 s after seizure onset was significantly correlated with correct localization. The subtraction method was superior to the visual method for localizing frontal lobe epilepsy (FLE) and parietal lobe epilepsy (PLE), and in patients with non-localizing/non-lateralizing EEG at onset. Ictal SPECT analyses using visual and subtraction methods are useful and complementary for the localization of the epileptogenic foci of neocortical epilepsy. Early radioligand injection and ictal EEG patterns are related to ictal SPECT localization. The subtraction method may be more useful in some epileptic syndromes. (orig.)

  13. Ictal spitting in left temporal lobe epilepsy: report of three cases.

    Science.gov (United States)

    Caboclo, Luís Otávio Sales Ferreira; Miyashira, Flavia Saori; Hamad, Ana Paula Andrade; Lin, Katia; Carrete, Henrique; Sakamoto, Américo Ceiki; Yacubian, Elza Márcia Targas

    2006-09-01

    Ictal spitting is rarely reported in patients with epilepsy. More often it is observed in patients with temporal lobe epilepsy (TLE) and is presumed to be a lateralizing sign to language nondominant hemisphere. We report three patients with left TLE who had ictal spitting registered during prolonged video-EEG monitoring. Medical charts of all patients with medically refractory partial epilepsy submitted to prolonged video-EEG monitoring in the Epilepsy Unit at UNIFESP during a 3-year period were reviewed, in search of reports of ictal spitting. The clinical, neurophysiological and neuroimaging data of the identified patients were reviewed. Among 136 patients evaluated with prolonged video-EEG monitoring, three (2.2%) presented spitting automatisms during complex partial seizures. All of them were right-handed, and had clear signs of left hippocampal sclerosis on MRI. In two patients, in all seizures in which ictal spitting was observed, EEG seizure onset was seen in the left temporal lobe. In the third patient, ictal onset with scalp electrodes was observed in the right temporal lobe, but semi-invasive monitoring with foramen ovale electrodes revealed ictal onset in the left temporal lobe, confirming false lateralization in surface records. The three patients became seizure-free following left anterior temporal lobectomy. Ictal spitting is a rare finding in patients with epilepsy, and may be considered a localizing sign of seizure onset in the temporal lobe. It may be observed in seizures originating from the left temporal lobe, and thus should not be considered a lateralizing sign of nondominant TLE.

  14. How Can We Identify Ictal and Interictal Abnormal Activity?

    Science.gov (United States)

    Fisher, Robert S.; Scharfman, Helen E.; deCurtis, Marco

    2015-01-01

    The International League Against Epilepsy (ILAE) defined a seizure as “a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.” This definition has been used since the era of Hughlings Jackson, and does not take into account subsequent advances made in epilepsy and neuroscience research. The clinical diagnosis of a seizure is empirical, based upon constellations of certain signs and symptoms, while simultaneously ruling out a list of potential imitators of seizures. Seizures should be delimited in time, but the borders of ictal (during a seizure), interictal (between seizures) and postictal (after a seizure) often are indistinct. EEG recording is potentially very helpful for confirmation, classification and localization. About a half-dozen common EEG patterns are encountered during seizures. Clinicians rely on researchers to answer such questions as why seizures start, spread and stop, whether seizures involve increased synchrony, the extent to which extra-cortical structures are involved, and how to identify the seizure network and at what points interventions are likely to be helpful. Basic scientists have different challenges in use of the word ‘seizure,’ such as distinguishing seizures from normal behavior, which would seem easy but can be very difficult because some rodents have EEG activity during normal behavior that resembles spike-wave discharge or bursts of rhythmic spiking. It is also important to define when a seizure begins and stops so that seizures can be quantified accurately for pre-clinical studies. When asking what causes seizures, the transition to a seizure and differentiating the pre-ictal, ictal and post-ictal state is also important because what occurs before a seizure could be causal and may warrant further investigation for that reason. These and other issues are discussed by three epilepsy researchers with clinical and basic science expertise. PMID:25012363

  15. Evaluation of epileptogenic focus in temporal lobe: correlation between ictal brain SPECT, magnetic resonance imaging and magnetic resonance spectroscopy; Avaliacao de foco epileptogenico do lobo temporal: correlacao entre SPECT ictal, ressonancia magnetica e ressonancia magnetica com espectroscopia de protons

    Energy Technology Data Exchange (ETDEWEB)

    Diegues, Maria Elena Martins [Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil). Servico de Medicina Nuclear]. E-mail: emartyns@terra.com.br; Pellini, Marcos Pinto; Alves-Leon, Soniza Vieira [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Medicina; Domingues, Romeu Cortes [Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro, RJ (Brazil)

    2004-02-01

    The purpose of this study was to determine the degree of concordance between radiological and radioisotopic methods and, if positive, to evaluate the usefulness of ictal SPECT in the localization of the epileptogenic focus. Ictal brain SPECT, magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) were performed on six patients with refractory temporal lobe epilepsy. Ictal SPECT was performed after withdrawal of the anti-epileptogenic drugs during video-EEG monitoring, using {sup 99m}Tc-ECD, administered to patients at the time of the ictus. MRI was performed in T1, T2 and FLAIR sequences and MRS was obtained using the PRESS technique, with a single voxel positioned in both hippocampi. The statistical analysis included the determination of the values of Kappa (k), standard error (se) and significance level (p) for the lateralization of the ictal focus. The analysis of all findings was based on EEG localization of the ictal discharge, seizure duration (109-280 s; 152 s average) and time of radiotracer injection (30-262 s; 96 s average). We obtained correlated data in four patients (67 per cent) and values of k = 0.67, se = 0.38, and p 0.041. We concluded that there is a concordance between ictal SPECT, MRI and MRS data and the usefulness of the radioisotopic procedure is related to a non diagnostic EEG and when there is a discordant or misleading diagnosis after a comparative analysis of EEG and MRS. (author)

  16. Ictal asystole mimicking seizure deterioration in temporal lobe epilepsy.

    Science.gov (United States)

    Guldiken, Baburhan; Hartl, Elisabeth; Rémi, Jan; Noachtar, Soheyl

    2015-09-01

    We report on a patient with temporal lobe epilepsy, secondary to a left lateral temporal cavernoma, in whom the change in seizure semiology suggested recurrence of secondary generalized seizures. Anticonvulsive medication previously controlled secondary generalized seizures over a period of years but focal seizures continued at a lower rate. Continuous video-EEG monitoring revealed ictal asystole associated with myoclonic syncope and falls during focal seizures arising from the left temporal lobe. After implantation of a cardiac pacemaker, no more falls occurred during the focal seizures. In conclusion, recurrence of seizure-associated falls is typically attributed to recurrence of secondary generalized seizures, however, ictal asystole should be considered in selected epilepsy patients as a differential diagnosis of falls. [Published with video sequence].

  17. High density scalp EEG in frontal lobe epilepsy.

    Science.gov (United States)

    Feyissa, Anteneh M; Britton, Jeffrey W; Van Gompel, Jamie; Lagerlund, Terrance L; So, Elson; Wong-Kisiel, Lilly C; Cascino, Gregory C; Brinkman, Benjamin H; Nelson, Cindy L; Watson, Robert; Worrell, Gregory A

    2017-01-01

    Localization of seizures in frontal lobe epilepsy using the 10-20 system scalp EEG is often challenging because neocortical seizure can spread rapidly, significant muscle artifact, and the suboptimal spatial resolution for seizure generators involving mesial frontal lobe cortex. Our aim in this study was to determine the value of visual interpretation of 76 channel high density EEG (hdEEG) monitoring (10-10 system) in patients with suspected frontal lobe epilepsy, and to evaluate concordance with MRI, subtraction ictal SPECT co-registered to MRI (SISCOM), conventional EEG, and intracranial EEG (iEEG). We performed a retrospective cohort study of 14 consecutive patients who underwent hdEEG monitoring for suspected frontal lobe seizures. The gold standard for localization was considered to be iEEG. Concordance of hdEEG findings with MRI, subtraction ictal SPECT co-registered to MRI (SISCOM), conventional 10-20 EEG, and iEEG as well as correlation of hdEEG localization with surgical outcome were examined. hdEEG localization was concordant with iEEG in 12/14 and was superior to conventional EEG 3/14 (pfrontal epilepsy requiring localization of epileptogenic brain. hdEEG may assist in developing a hypothesis for iEEG monitoring and could potentially augment EEG source localization. Published by Elsevier B.V.

  18. The correlation between ictal semiology and magnetoencephalographic localization in frontal lobe epilepsy.

    Science.gov (United States)

    Wu, Xintong; Rampp, Stefan; Weigel, Daniel; Kasper, Burkhard; Zhou, Dong; Stefan, Hermann

    2011-11-01

    The aim of this study was to investigate the correlation of ictal semiology with localization and/or lateralization by magnetoencephalography (MEG). Seven patients from the Neurology Department of the University Hospital Erlangen who underwent resective surgery for frontal lobe epilepsy (FLE) with an Engel 1a outcome were investigated retrospectively. MEG localizations were classified according to five compartments (separate or combined) of the frontal lobe: frontal basal (FB), frontal lateral (FL), frontal polar (FP), frontal mesial (FM), and frontal precentral (FPr). On the basis of previous studies that investigated the value of ictal semiology in localization and lateralization, we compared the experiential localization and/or lateralization of the epileptogenic region deduced from ictal semiology, that is, both seizure history and ictal video/EEG monitoring, with MEG localization. It is easier to determine lateralization than localization from ictal semiology because of the variety of signs and fast propagation in FLE. All of the patients had specific MEG localizations according to favorable postoperative outcome. Three patients had MEG foci associated with ictal semiology; in another four, the MEG localization was adjacent to the estimated area suggested by ictal semiology. Head version signs could be observed in all compartments of the frontal lobe: clonic in FB and FP areas; postural in FPr, FL, and FM areas; hypermotor in FB, FP, FPr, and FM areas; sensation aura in FB, FL, and FM areas; and automatisms in FP, FPr, and FL areas. All patients had concordant lateralizing and limited valuable locating information from ictal semiology, but no complete correlation with MEG foci. Ictal semiology may indicate the involvement of a symptomatogenic brain region during a seizure, but extent of seizure onset in central motor or sensorimotor area is not reliable enough to indicate the seizure onset zone and favorable postoperative outcome in FLE. MEG provided specific

  19. Contribution of subtraction ictal SPECT coregistered to MRI to epilepsy surgery. A multicenter study

    International Nuclear Information System (INIS)

    Matsuda, Hiroshi; Matsuda, Kazumi; Nakamura, Fumihiro

    2009-01-01

    A multicenter prospective study was performed to assess the additional value of a subtraction ictal single photon emission computed tomography (SPECT) coregistered to MRI (SISCOM) technique to traditional side-by-side comparison of ictal- and interictal SPECT images in epilepsy surgery. One hundred and twenty-three patients with temporal and extratemporal lobe epilepsy who had undergone epilepsy surgery after evaluation of scalp ictal and interictal electroencephalogram (EEG), MRI, and ictal and interictal SPECT scans were followed up in terms of postsurgical outcome for a period of at least 1 year. Three reviewers localized the epileptogenic focus using ictal and interictal SPECT images first by side-by-side comparison and subsequently by SISCOM. Concordance of the localization of the epileptogenic focus by SPECT diagnosis with the surgical site and inter-observer agreement between reviewers was compared between side-by-side comparison and SISCOM. Logistic regression analysis was performed in predicting the surgical outcome with the dependent variable being the achievement of a good postsurgical outcome and the independent variables using the SISCOM, side-by-side comparison of ictal and interictal SPECT images, MRI, and scalp ictal EEG. The SISCOM presented better concordance in extratemporal lobe epilepsy and less concordance in temporal lobe epilepsy than side-by-side comparison. Inter-observer concordance was higher in SISCOM than in side-by-side comparison. Much higher concordance of the epileptogenic focus by SPECT diagnosis with the surgical site was obtained in patients with good surgical outcome than in those with poor surgical outcome. These differences in concordance between good and poor surgical outcomes were greater in SISCOM than in side-by-side comparison. Logistic regression analysis showed the highest odds ratio of 12.391 (95% confidence interval; 3.319, 46.254) by SISCOM evaluation for concordance of the epileptogenic focus with the surgical site

  20. Ictal cerebral perfusion patterns in partial epilepsy: SPECT subtraction

    International Nuclear Information System (INIS)

    Lee, Hyang Woon; Hong, Seung Bong; Tae, Woo Suk; Kim, Sang Eun; Seo, Dae Won; Jeong, Seung Cheol; Yi, Ji Young; Hong, Seung Chyul

    2000-01-01

    To investigate the various ictal perfusion patterns and find the relationships between clinical factors and different perfusion patterns. Interictal and ictal SPECT and SPECT subtraction were performed in 61 patients with partial epilepsy. Both positive images showing ictal hyperperfusion and negative images revealing ictal hypoperfusion were obtained by SPECT subtraction. The ictal perfusion patterns of subtracted SPECT were classified into focal hyperperfusion, hyperperfusion-plus, combined hyperperfusion-hypoperfusion, and focal hypoperfusion only. The concordance rates with epileptic focus were 91.8% in combined analysis of ictal hyperperfusion and hypoperfusion images of subtracted SPECT, 85.2% in hyperperfusion images only of subtracted SPECT, and 68.9% in conventional ictal SPECT analysis. Ictal hypoperfusion occurred less frequently in temporal lobe epilepsy (TLE) than extratemporal lobe epilepsy. Mesial temporal hyperperfusion alone was seen only in mesial TLE while lateral temporal hyperperfusion alone was observed only in neocortical TLE. Hippocampal sclerosis had much lower incidence of ictal hypoperfusion than any other pathology. Some patients showed ictal hypoperfusion at epileptic focus with ictal hyperperfusion in the neighboring brain regions where ictal discharges propagated. Hypoperfusion as well as hyperperfusion in ictal SPECT should be considered for localizing epileptic focus. Although the mechanism of ictal hypoperfusion could be an intra-ictal early exhaustion of seizure focus or a steal phenomenon by the propagation of ictal discharges to adjacent brain areas, further study is needed to elucidate it.=20

  1. Significant Post-ictal Hypotension: Expanding the Spectrum of Seizure Induced Autonomic Dysregulation

    Science.gov (United States)

    Bozorgi, Alireza; Chung, Stephanie; Kaffashi, Farhad; Loparo, Kenneth A; Sahoo, Satya; Zhang, GQ; Kaiboriboon, Kitti; Lhatoo, Samden D

    2013-01-01

    Summary Peri-ictal autonomic dysregulation is best studied using a “polygraphic” approach (EEG, 3-channel EKG, pulse Oximetry, respiration and continuous non-invasive blood pressure [BP]) and may help elucidate agonal pathophysiological mechanisms leading to Sudden Unexpected Death in Epilepsy (SUDEP). A number of autonomic phenomena have been described in generalized tonic-clonic seizures (GTCS), the commonest seizure type associated with SUDEP, including decreased heart rate variability, cardiac arrhythmias and changes in skin conductance. Post-ictal generalized EEG suppression (PGES) has been identified as a potential risk marker of SUDEP and PGES has been found to correlate with post GTCS autonomic dysregulation in some patients. Here, we describe a patient with a GTCS in whom polygraphic measurements, including continuous non-invasive blood pressure recordings, were obtained. Significant post-ictal hypotension lasting >60 seconds was found which closely correlated with PGES duration. Similar EEG changes are well described in hypotensive patients with vasovagal syncope and a similar vasodepressor phenomenon and consequent cerebral hypo-perfusion may account for the PGES observed in some patients after a GTCS. This further raises the possibility that profound, prolonged and irrecoverable hypotension may comprise one potential SUDEP mechanism. PMID:23758665

  2. Predictive values of F-18-FDG PET and ictal SPECT to find epileptogenic zones in cryptogenic neocortical epilepsies

    International Nuclear Information System (INIS)

    Lee, D. S.; Lee, S. K.; Jeong, Z. K.; Kim, H. Z.; Lee, M. C.; Ko, C. S.

    1997-01-01

    Though cumulated reported sensitivity were 33% (F-18-FDG PET) and 81%(ictal SPECT) in neocortical epilepsy, positive predictive values rather than sensitivity should be referred if we wish to know the reliability of positive findings to predict epileptogenic zones. In cryptogenic neocortical epilepsy which did not have structural lesions on MR, we tried to find performance of F-18-FDG PET and ictal SPECT to find epileptogenic zones. In 77 patients who had no lesion on MR and who were suspected to have neocortical epilepsy on video monitored EEG, ictal SPECT were done in 44 patients and F-18-FDG PET were done in 70 patients. Invasive study and operation was done in 24 patients. The most hyper perfused area or prominently hypometabolic area was suspected to be epileptogenic on ictal SPECT or F-18-FDG PET, respectively. We could find zones of ictal hyperperfusion in 34/44(78%) patients. Positive predictive values of ictal hyperperfusion were 58%, 60%, and 12.5% in frontal lobes (n=12), lateral temporal lobes (20), and parietal lobes (8). We could find hypometabolic areas in 50/70(76%) patients. Positive predictive values of hypometabolism were 78%, 71%, 33%, and 25% in frontal lobes (9), lateral temporal lobes (28), parietal lobes (3) and occipital lobes (4). Among 24 patients who were operated, 17 patients were followed up more than 7 months (15 ± 5). Thirteen patients improved (10 : Engel class I or II, 2: 90% reduction, 1: 75% reduction but multifocal). Five among 11 PET studies were correct, 3 among 10 SPECT studies, and 6 among 11 PET/SPECT studies (55%) were correct for localization. In conclusion, three fourths of patients gave positive results to localized epileptogenic zones in cryptogenic neocortical epilepsy, and predictive values of ictal hyperperfusion or interictal hypometabolism were highest in frontal or lateral temporal lobes if these lobes were found to be culprit though rapid ictal propagation of cortical hyperperfusion confounded the exact

  3. Ictal central apnea and bradycardia in temporal lobe epilepsy complicated by obstructive sleep apnea syndrome

    Directory of Open Access Journals (Sweden)

    Yoko Nishimura

    2015-01-01

    Full Text Available We describe the case of a 12-year-old boy who developed temporal lobe epilepsy (TLE with daily complex partial seizures (CPS and monthly generalized seizures. Moreover, he frequently snored while asleep since early childhood. Polysomnography (PSG revealed severe obstructive sleep apnea with apnea–hypopnea index (AHI of 37.8/h. Video-PSG with simultaneous electroencephalography (EEG recording captured two ictal apneic episodes during sleep, without any motor manifestations. The onset of rhythmic theta activity in the midtemporal area on EEG was preceded by the onset of apnea by several seconds and disappeared soon after cessation of central apnea. One episode was accompanied by ictal bradycardia of <48 beats/min which persisted for 50 s beyond the end of epileptic activity. After treatment with carbamazepine and tonsillectomy/adenoidectomy, the seizures were well controlled and AHI decreased to 2.5/h. Paroxysmal discharges also disappeared during this time. Uncontrolled TLE complicated by sleep apnea should be evaluated for the presence of ictal central apnea/bradycardia.

  4. Video-electrographic and clinical features in patients with ictal asystole.

    Science.gov (United States)

    Schuele, S U; Bermeo, A C; Alexopoulos, A V; Locatelli, E R; Burgess, R C; Dinner, D S; Foldvary-Schaefer, N

    2007-07-31

    Ictal asystole (IA) is a rare event mostly seen in patients with temporal lobe epilepsy (TLE) and a potential contributor to sudden unexplained death in epilepsy (SUDEP). Clinical and video-electroencephalographic findings associated with IA have not been described, and may be helpful in screening for high risk patients. A database search was performed of 6,825 patients undergoing long-term video-EEG monitoring for episodes of IA. IA was recorded in 0.27% of all patients with epilepsy, eight with temporal (TLE), two with extratemporal (XTLE), and none with generalized epilepsy. In 8 out of 16 recorded events, all occurring in patients with TLE, seizures were associated with a sudden atonia on average 42 seconds into the typical semiology of a complex partial seizure. The loss of tone followed after a period of asystole usually lasting longer than 8 seconds and was associated with typical EEG changes seen otherwise with cerebral hypoperfusion. Clinical predisposing factors for IA including cardiovascular risk factors or baseline ECG abnormalities were not identified. Ictal asystole is a rare feature of patients with focal epilepsy. Delayed loss of tone is distinctly uncommon in patients with temporal lobe seizures, but may inevitably occur in patients with ictal asystole after a critical duration of cardiac arrest and cerebral hypoperfusion. Further cardiac monitoring in patients with temporal lobe epilepsy and a history of unexpected collapse and falls late in the course of a typical seizure may be warranted and can potentially help to prevent sudden unexplained death in epilepsy.

  5. Ictal PET in presurgical workup of refractory extratemporal epilepsy

    Directory of Open Access Journals (Sweden)

    Javeria Nooraine

    2013-01-01

    Full Text Available Ictal Pet in presurgical workup of refractory epilepsy is seldom performed and limited due to technical difficulties. In carefully selected patient subset with frequent extratemporal seizures, ictal PET depicts ′seizure onset zone′ with high spatial resolution even within a widespread pathology. We here depict a four year old with posterior quadrant dysplasia evaluated with ictal PET.

  6. Standardized computer-based organized reporting of EEG

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Aurlien, Harald; Brøgger, Jan C.

    2017-01-01

    . In the end, the diagnostic significance is scored, using a standardized list of terms. SCORE has specific modules for scoring seizures (including seizure semiology and ictal EEG patterns), neonatal recordings (including features specific for this age group), and for Critical Care EEG Terminology. SCORE...... in the second, revised version of SCORE (Standardized Computer-based Organized Reporting of EEG), which is presented in this paper. The revised terminology was implemented in a software package (SCORE EEG), which was tested in clinical practice on 12,160 EEG recordings. Standardized terms implemented in SCORE...... is a useful clinical tool, with potential impact on clinical care, quality assurance, data-sharing, research and education....

  7. Sign of the Cross (Signum Crucis): observation of an uncommon ictal manifestation of mesial temporal lobe epilepsy.

    Science.gov (United States)

    Lin, Katia; Marx, Catherine; Caboclo, Luis O S F; Centeno, Ricardo S; Sakamoto, Américo C; Yacubian, Elza M T

    2009-02-01

    The objective of the study was to describe the clinical characteristics and determine the lateralizing value of ictal Sign of the Cross (SC) as a complex hand automatism (CHA) in patients evaluated by video/EEG monitoring in a comprehensive epilepsy unit. We reviewed video/EEG data of 530 patients with epilepsy recorded in a tertiary epilepsy center from 2002 to 2008. Four patients were found to have manifested a CHA similar to the SC at least once during their complex partial seizures. All patients had unilateral right mesial temporal lobe epilepsy (TLE) refractory to medical treatment. The limbic system is often suggested as the critical site of religious experience. Moreover, it may be localized predominantly to the temporal regions of the right hemisphere. However, this rare and peculiar ictal manifestation may be related not only to the neural substrate and personality characteristics of TLE, but also to the general religious convictions of Brazilians.

  8. The early electroclinical manifestations of infantile spasms: A video EEG study.

    Science.gov (United States)

    Iype, Mary; Kunju, Puthuvathra Abdul Mohammed; Saradakutty, Geetha; Mohan, Devi; Khan, Shahanaz Ahamed Mohammed

    2016-01-01

    Infantile spasms are described as flexor extensor and mixed; but more features of their semiology and ictal electroencephalography (EEG) changes are sparse in the literature. The purpose of the study was to describe the clinical and ictal video-EEG characteristics of consecutive cases with infantile spasms and to try to find an association with the etiology. The clinical phenomenology and EEG characteristics on video-EEG were analyzed in 16 babies with infantile spasms. A total of 869 spasms were reviewed. Nine (56.3%) showed focal seizures at least once during the recording and 1 (6.3%) had multifocal myoclonus in addition to the spasms. The duration of the cluster and interval between spasms was totally variable in all patients. Lateralizing phenomena were present in at least some of the spasms in all patients. Unilateral manual automatism in the form of holding the pinna was noted in three patients following the spasm. The ictal EEG activity in the majority (75%) was the slow wave. Four (25%) showed fast generalized spindle-like ictal discharges. Spikes, spike and wave activity, or electrodecremental pattern alone during the ictus was seen in none. On bivariate analysis, no factor noted on the video EEG had association with the etiology. Infantile spasms could be associated with focal and other seizures, has unique, non-uniform and variable semiology from patient to patient. The ictal EEG manifestation in the majority (75%) of our patients was the slow wave transient with 25% showing generalized fast spindle-like activity.

  9. Ictal brain SPET during seizures pharmacologically provoked with pentylenetetrazol: a new diagnostic procedure in drug-resistant epileptic patients

    International Nuclear Information System (INIS)

    Calcagni, Maria Lucia; Giordano, Alessandro; Bruno, Isabella; Di Giuda, Daniela; De Rossi, Giuseppe; Troncone, Luigi; Parbonetti, Giovanni; Colicchio, Gabriella

    2002-01-01

    Functional brain imaging plays an important role in seizure focus localisation. However, truly ictal single-photon emission tomography (SPET) studies are not routinely performed owing to technical problems associated with the use of tracers and methodological and logistical difficulties. In this study we tried to resolve both of these issues by means of a new procedure: technetium-99m ethyl cysteinate dimer (ECD) brain SPET performed during seizures pharmacologically provoked with pentylenetetrazol, a well-known central and respiratory stimulant. We studied 33 drug-resistant epileptic patients. All patients underwent anamnestic evaluation, neuropsychological and psychodynamic assessment, magnetic resonance imaging, interictal and ictal video-EEG monitoring, and interictal and ictal SPET with 99m Tc-ECD. In order to obtain truly ictal SPET, 65 mg of pentylenetetrazol was injected every 2 minutes and, immediately the seizure began, 740 MBq of 99m Tc-ECD was injected. The scintigraphic findings were considered abnormal if a single area of hyperperfusion was present and corresponded to the site of a single area of hypoperfusion at interictal SPET: the ''hypo-hyperperfusion'' SPET pattern. In 27 of the 33 patients (82%), interictal-ictal SPET showed the hypo-hyperperfusion SPET pattern. Video-EEG showed a single epileptogenic zone in 21/33 patients (64%), and MRI showed anatomical lesions in 19/33 patients (57%). Twenty-two of the 27 patients with hypo-hyperperfusion SPET pattern underwent ablative or palliative surgery and were seizure-free at 3 years of follow-up. No adverse effects were noted during pharmacologically provoked seizure. It is concluded that ictal brain SPET performed during pharmacologically provoked seizure provides truly ictal images because 99m Tc-ECD is injected immediately upon seizure onset. Using this feasible procedure it is possible to localise the focus, to avoid the limitations due to the unpredictability of seizures, to avoid pitfalls due

  10. Ictal brain SPET during seizures pharmacologically provoked with pentylenetetrazol: a new diagnostic procedure in drug-resistant epileptic patients

    Energy Technology Data Exchange (ETDEWEB)

    Calcagni, Maria Lucia; Giordano, Alessandro; Bruno, Isabella; Di Giuda, Daniela; De Rossi, Giuseppe; Troncone, Luigi [Department of Nuclear Medicine, Universita Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Roma (Italy); Parbonetti, Giovanni; Colicchio, Gabriella [Department of Neurosurgery, Universita Cattolica del Sacro Cuore, Roma (Italy)

    2002-10-01

    Functional brain imaging plays an important role in seizure focus localisation. However, truly ictal single-photon emission tomography (SPET) studies are not routinely performed owing to technical problems associated with the use of tracers and methodological and logistical difficulties. In this study we tried to resolve both of these issues by means of a new procedure: technetium-99m ethyl cysteinate dimer (ECD) brain SPET performed during seizures pharmacologically provoked with pentylenetetrazol, a well-known central and respiratory stimulant. We studied 33 drug-resistant epileptic patients. All patients underwent anamnestic evaluation, neuropsychological and psychodynamic assessment, magnetic resonance imaging, interictal and ictal video-EEG monitoring, and interictal and ictal SPET with {sup 99m}Tc-ECD. In order to obtain truly ictal SPET, 65 mg of pentylenetetrazol was injected every 2 minutes and, immediately the seizure began, 740 MBq of {sup 99m}Tc-ECD was injected. The scintigraphic findings were considered abnormal if a single area of hyperperfusion was present and corresponded to the site of a single area of hypoperfusion at interictal SPET: the ''hypo-hyperperfusion'' SPET pattern. In 27 of the 33 patients (82%), interictal-ictal SPET showed the hypo-hyperperfusion SPET pattern. Video-EEG showed a single epileptogenic zone in 21/33 patients (64%), and MRI showed anatomical lesions in 19/33 patients (57%). Twenty-two of the 27 patients with hypo-hyperperfusion SPET pattern underwent ablative or palliative surgery and were seizure-free at 3 years of follow-up. No adverse effects were noted during pharmacologically provoked seizure. It is concluded that ictal brain SPET performed during pharmacologically provoked seizure provides truly ictal images because {sup 99m}Tc-ECD is injected immediately upon seizure onset. Using this feasible procedure it is possible to localise the focus, to avoid the limitations due to the unpredictability

  11. Avaliação de foco epileptogênico do lobo temporal: correlação entre SPECT ictal, ressonância magnética e ressonância magnética com espectroscopia de prótons Evaluation of epileptogenic focus in temporal lobe: correlation between ictal brain SPECT, magnetic resonance imaging and magnetic resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Maria Elena Martins Diegues

    2004-02-01

    Full Text Available O objetivo deste trabalho foi determinar a existência de concordância entre os métodos radioisotópico e radiológico e, em caso positivo, avaliar a utilidade do SPECT ictal na determinação do foco epileptogênico. Foram realizados SPECT ictal, ressonância magnética (RM e ressonância magnética com espectroscopia de prótons (RME em seis pacientes com epilepsia de lobo temporal refratária. O SPECT ictal foi realizado após a retirada das drogas antiepilépticas durante monitoramento por vídeo-EEG, utilizando-se o 99mTc-ECD, administrado aos pacientes no início da crise. As imagens de RM foram obtidas em T1, T2 e FLAIR, com cortes de 3 e 5 mm de espessura, e a RME foi realizada com técnica PRESS, com voxel único posicionado no hipocampo, bilateralmente. A análise estatística incluiu os valores de Kappa (k, erro-padrão (ep e o nível de significância (p para a lateralização do foco. Os achados foram analisados com base na localização por EEG da descarga ictal, no tempo de duração da crise (109-280 s; média: 152 s e no tempo de administração do traçador (30-262 s; média: 96 s. Obtivemos dados correlatos em quatro pacientes (67%, com valores de k = 0,67, ep = 0,38 e p = 0,041. Concluímos que existe concordância entre SPECT ictal, RM e RME, e a utilidade do procedimento radioisotópico está relacionada aos casos em que o EEG não é diagnóstico e quando há discordância ou indefinição diagnóstica na análise comparativa entre EEG, RM e RME.The purpose of this study was to determine the degree of concordance between radiological and radioisotopic methods and, if positive, to evaluate the usefulness of ictal SPECT in the localization of the epileptogenic focus. Ictal brain SPECT, magnetic resonance imaging (MRI and magnetic resonance spectroscopy (MRS were performed on six patients with refractory temporal lobe epilepsy. Ictal SPECT was performed after withdrawal of the anti-epileptogenic drugs during video-EEG

  12. Unusual ictal foreign language automatisms in temporal lobe epilepsy.

    Science.gov (United States)

    Soe, Naing Ko; Lee, Sang Kun

    2014-12-01

    The distinct brain regions could be specifically involved in different languages and the differences in brain activation depending on the language proficiency and on the age of language acquisition. Speech disturbances are observed in the majority of temporal lobe complex motor seizures. Ictal verbalization had significant lateralization value: 90% of patients with this manifestation had seizure focus in the non-dominant temporal lobe. Although, ictal speech automatisms are usually uttered in the patient's native language, ictal speech foreign language automatisms are unusual presentations of non-dominent temporal lobe epilepsy. The release of isolated foreign language area could be possible depending on the pattern of ictal spreading of non-dominant hemisphere. Most of the case reports in ictal speech foreign language automatisms were men. In this case report, we observed ictal foreign language automatisms in middle age Korean woman.

  13. A self-adapting system for the automated detection of inter-ictal epileptiform discharges.

    Directory of Open Access Journals (Sweden)

    Shaun S Lodder

    Full Text Available PURPOSE: Scalp EEG remains the standard clinical procedure for the diagnosis of epilepsy. Manual detection of inter-ictal epileptiform discharges (IEDs is slow and cumbersome, and few automated methods are used to assist in practice. This is mostly due to low sensitivities, high false positive rates, or a lack of trust in the automated method. In this study we aim to find a solution that will make computer assisted detection more efficient than conventional methods, while preserving the detection certainty of a manual search. METHODS: Our solution consists of two phases. First, a detection phase finds all events similar to epileptiform activity by using a large database of template waveforms. Individual template detections are combined to form "IED nominations", each with a corresponding certainty value based on the reliability of their contributing templates. The second phase uses the ten nominations with highest certainty and presents them to the reviewer one by one for confirmation. Confirmations are used to update certainty values of the remaining nominations, and another iteration is performed where ten nominations with the highest certainty are presented. This continues until the reviewer is satisfied with what has been seen. Reviewer feedback is also used to update template accuracies globally and improve future detections. KEY FINDINGS: Using the described method and fifteen evaluation EEGs (241 IEDs, one third of all inter-ictal events were shown after one iteration, half after two iterations, and 74%, 90%, and 95% after 5, 10 and 15 iterations respectively. Reviewing fifteen iterations for the 20-30 min recordings 1 took approximately 5 min. SIGNIFICANCE: The proposed method shows a practical approach for combining automated detection with visual searching for inter-ictal epileptiform activity. Further evaluation is needed to verify its clinical feasibility and measure the added value it presents.

  14. Ictal technetium-99 m ethyl cysteinate dimer single-photon emission tomographic findings in epileptic patients with polymicrogyria syndromes: A subtraction of ictal-interictal SPECT coregistered to MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Wichert-Ana, Lauro [University of Sao Paulo, Center for Epilepsy Surgery, Department of Neurology, Psychiatry and Clinical Psychology, Ribeirao Preto (Brazil); Hospital das Clinicas, USP, Centro de Cirurgia de Epilepsia, CIREP, Ribeirao Preto, SP (Brazil); Mazzoncini de Azevedo-Marques, Paulo; Santos, Antonio C.; Araujo, David [University of Sao Paulo, Center for Imaging Science and Medical Physics, Department of Internal Medicine, Ribeirao Preto (Brazil); Ferrari Oliveira, Lucas [Federal University of Pelotas, Informatics Department, Pelotas, RS (Brazil); Fernandes, Regina M.F.; Velasco, Tonicarlo R.; Sakamoto, Americo C. [University of Sao Paulo, Center for Epilepsy Surgery, Department of Neurology, Psychiatry and Clinical Psychology, Ribeirao Preto (Brazil); Kato, Mery [University of Sao Paulo, Division of Nuclear Medicine, Department of Internal Medicine from the Ribeirao Preto Medical School, Ribeirao Preto (Brazil); Muxfeldt Bianchin, Marino [Rio Grande do Sul Federal University, Neurology Division, HCPA, Porto Alegre, RS (Brazil)

    2008-06-15

    To describe the ictal technetium-99 m-ECD SPECT findings in polymicrogyria syndromes (PMG) during epileptic seizures. We investigated 17 patients with PMG syndromes during presurgical workup, which included long-term video-electroencephalographic (EEG) monitoring, neurological and psychiatry assessments, invasive EEG, and the subtraction of ictal-interictal SPECT coregistered to magnetic resonance imaging (MRI) (SISCOM). The analysis of the PMG cortex, using SISCOM, revealed intense hyperperfusion in the polymicrogyric lesion during epileptic seizures in all patients. Interestingly, other localizing investigations showed heterogeneous findings. Twelve patients underwent epilepsy surgery, three achieved seizure-freedom, five have worthwhile improvement, and four patients remained unchanged. Our study strongly suggests the involvement of PMG in seizure generation or early propagation. Both conventional ictal single-photon emission computed tomography (SPECT) and SISCOM appeared as the single contributive exam to suggest the localization of the epileptogenic zone. Despite the limited number of resective epilepsy surgery in our study (n = 9), we found a strong prognostic role of SISCOM in predicting surgical outcome. This result may be of great value on surgical decision-making of whether or not the whole or part of the PMG lesion should be surgically resected. (orig.)

  15. Interictal to Ictal Phase Transition in a Small-World Network

    Science.gov (United States)

    Nemzer, Louis; Cravens, Gary; Worth, Robert

    Real-time detection and prediction of seizures in patients with epilepsy is essential for rapid intervention. Here, we perform a full Hodgkin-Huxley calculation using n 50 in silico neurons configured in a small-world network topology to generate simulated EEG signals. The connectivity matrix, constructed using a Watts-Strogatz algorithm, admits randomized or deterministic entries. We find that situations corresponding to interictal (non-seizure) and ictal (seizure) states are separated by a phase transition that can be influenced by congenital channelopathies, anticonvulsant drugs, and connectome plasticity. The interictal phase exhibits scale-free phenomena, as characterized by a power law form of the spectral power density, while the ictal state suffers from pathological synchronization. We compare the results with intracranial EEG data and show how these findings may be used to detect or even predict seizure onset. Along with the balance of excitatory and inhibitory factors, the network topology plays a large role in determining the overall characteristics of brain activity. We have developed a new platform for testing the conditions that contribute to the phase transition between non-seizure and seizure states.

  16. A comparative study of EEG abnormalities among subjects with inter ...

    African Journals Online (AJOL)

    Background: Electrophysiological investigation is an integral part in the management of neuropsychiatric disorders; but this is rare in developing countries including Nigeria. Objectives: The study aims to determine EEG abnormalities among subjects with inter-ictal psychosis in comparison to those with schizophrenia.

  17. Ictal and peri-ictal oscillations in the human basal ganglia in temporal lobe epilepsy

    Czech Academy of Sciences Publication Activity Database

    Rektor, I.; Kuba, R.; Brázdil, M.; Halámek, Josef; Jurák, Pavel

    2011-01-01

    Roč. 20, č. 3 (2011), s. 512-517 ISSN 1525-5050 Institutional research plan: CEZ:AV0Z20650511 Keywords : basal ganglia * oscillations * epilepsy * ictal Subject RIV: FH - Neurology Impact factor: 2.335, year: 2011

  18. Distribution entropy analysis of epileptic EEG signals.

    Science.gov (United States)

    Li, Peng; Yan, Chang; Karmakar, Chandan; Liu, Changchun

    2015-01-01

    It is an open-ended challenge to accurately detect the epileptic seizures through electroencephalogram (EEG) signals. Recently published studies have made elaborate attempts to distinguish between the normal and epileptic EEG signals by advanced nonlinear entropy methods, such as the approximate entropy, sample entropy, fuzzy entropy, and permutation entropy, etc. Most recently, a novel distribution entropy (DistEn) has been reported to have superior performance compared with the conventional entropy methods for especially short length data. We thus aimed, in the present study, to show the potential of DistEn in the analysis of epileptic EEG signals. The publicly-accessible Bonn database which consisted of normal, interictal, and ictal EEG signals was used in this study. Three different measurement protocols were set for better understanding the performance of DistEn, which are: i) calculate the DistEn of a specific EEG signal using the full recording; ii) calculate the DistEn by averaging the results for all its possible non-overlapped 5 second segments; and iii) calculate it by averaging the DistEn values for all the possible non-overlapped segments of 1 second length, respectively. Results for all three protocols indicated a statistically significantly increased DistEn for the ictal class compared with both the normal and interictal classes. Besides, the results obtained under the third protocol, which only used very short segments (1 s) of EEG recordings showed a significantly (p entropy algorithm. The capability of discriminating between the normal and interictal EEG signals is of great clinical relevance since it may provide helpful tools for the detection of a seizure onset. Therefore, our study suggests that the DistEn analysis of EEG signals is very promising for clinical and even portable EEG monitoring.

  19. Neural network underlying ictal pouting ("chapeau de gendarme") in frontal lobe epilepsy.

    Science.gov (United States)

    Souirti, Zouhayr; Landré, Elisabeth; Mellerio, Charles; Devaux, Bertrand; Chassoux, Francine

    2014-08-01

    In order to determine the anatomical neural network underlying ictal pouting (IP), with the mouth turned down like a "chapeau de gendarme", in frontal lobe epilepsy (FLE), we reviewed the video-EEG recordings of 36 patients with FLE who became seizure-free after surgery. We selected the cases presenting IP, defined as a symmetrical and sustained (>5s) lowering of labial commissures with contraction of chin, mimicking an expression of fear, disgust, or menace. Ictal pouting was identified in 11 patients (8 males; 16-48 years old). We analyzed the clinical semiology, imaging, and electrophysiological data associated with IP, including FDG-PET in 10 and SEEG in 9 cases. In 37 analyzed seizures (2-7/patient), IP was an early symptom, occurring during the first 10s in 9 cases. The main associated features consisted of fear, anguish, vegetative disturbances, behavioral disorders (sudden agitation, insults, and fighting), tonic posturing, and complex motor activities. The epileptogenic zone assessed by SEEG involved the mesial frontal areas, especially the anterior cingulate cortex (ACC) in 8 patients, whereas lateral frontal onset with an early spread to the ACC was seen in the other patient. Ictal pouting associated with emotional changes and hypermotor behavior had high localizing value for rostroventral "affective" ACC, whereas less intense facial expressions were related to the dorsal "cognitive" ACC. Fluorodeoxyglucose positron emission tomography demonstrated the involvement of both the ACC and lateral cortex including the anterior insula in all cases. We propose that IP is sustained by reciprocal mesial and lateral frontal interactions involved in emotional and cognitive processes, in which the ACC plays a pivotal role. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Ictal and postictal semiology in patients with bilateral temporal lobe epilepsy.

    Science.gov (United States)

    Řehulka, Pavel; Doležalová, Irena; Janoušová, Eva; Tomášek, Martin; Marusič, Petr; Brázdil, Milan; Kuba, Robert

    2014-12-01

    Bilateral temporal lobe epilepsy is characterized by evidence of seizure onset independently in both temporal lobes. The main aim of the present study was to determine whether patients with evidence of independent bilateral temporal lobe epilepsy (biTLE) can be identified noninvasively on the basis of seizure semiology analysis. Thirteen patients with biTLE, as defined by invasive EEG, were matched with 13 patients with unilateral temporal lobe epilepsy (uniTLE). In all 26 patients, the frequency of predefined clusters of ictal and periictal signs were evaluated: ictal motor signs (IMSs), periictal motor signs (PIMSs), periictal vegetative signs (PIVSs), the frequency of early oroalimentary automatisms (EOAs), and the duration of postictal unresponsiveness (PU). Some other noninvasive and clinical data were also evaluated. A lower frequency of IMSs was noted in the group with biTLE (patients = 46.2%, seizures = 20.7%) than in the group with uniTLE (patients = 92.3%, seizures = 61.0%) (p = 0.030; p < 0.001, respectively). The individual IMS average per seizure was significantly lower in the group with biTLE (0.14; range = 0-1.0) than in the group with uniTLE (0.80; range = 0-2.6) (p = 0.003). Postictal unresponsiveness was longer than 5 min in more patients (75.0%) and seizures (42.9%) in the group with biTLE than in the group with uniTLE (patients = 30.8%, seizures = 18.6%) (p = 0.047; p = 0.002). The frequency of EOAs, PIMSs, PIVSs, and other clinical data did not differ significantly. There is a lower frequency of ictal motor signs and longer duration of postictal unresponsiveness in patients with biTLE. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Headache as an Aura of Epilepsy: Video-EEG Monitoring Study.

    Science.gov (United States)

    Kim, Dong Wook; Sunwoo, Jun-Sang; Lee, Sang Kun

    2016-04-01

    Headache can be associated with epilepsy as a pre-ictal, ictal, or post-ictal phenomenon; however, studies of patients with headache as an epileptic aura are scarce. We performed the present study to investigate the incidence and characteristics of headache as an epileptic aura, via confirmation of electroencephalography (EEG) changes by video-EEG monitoring. Data of aura and clinical seizure episodes of 831 consecutive patients who undertook video-EEG monitoring were analyzed retrospectively. For patients who had headache as an aura, information on the detailed features of headache was acquired, including location, nature, duration, and the presence of accompanying symptoms. Video-recorded clinical seizures, EEG findings, and neuroimaging data were used to determine the ictal onset areas in the patients. Six out of 831 (0.7%) patients experienced headache as aura (age range, 25-52 years), all of whom had partial seizures. The incidence of pre-ictal headache was 6.3% (25/831), and post-ictal headache was 30.9% (257/831). In patients with headache as aura, five patients described headache as the most frequent aura, and headache was the second most frequent aura in one patient. The characteristics of headache were hemicrania epileptica in two patients, tension-type headache in another two patients, and migraine-like headache in the remaining two patients. No patient met the diagnostic criteria of ictal epileptic headache or migraine aura-triggered seizure. Our study showed that headache as an aura is uncommon in adult patients with epilepsy, and that headache can present as diverse features, including hemicrania epileptica, tension-type headache, and migraine-like headache. Further studies are necessary to characterize the features of headache as an epileptic aura in adult patients with epilepsy. © 2016 American Headache Society.

  2. Characterisation of ictal and interictal states of epilepsy: A system dynamic approach of principal dynamic modes analysis.

    Directory of Open Access Journals (Sweden)

    Zabit Hameed

    Full Text Available Epilepsy is a brain disorder characterised by the recurrent and unpredictable interruptions of normal brain function, called epileptic seizures. The present study attempts to derive new diagnostic indices which may delineate between ictal and interictal states of epilepsy. To achieve this, the nonlinear modeling approach of global principal dynamic modes (PDMs is adopted to examine the functional connectivity of the temporal and frontal lobes with the occipital brain segment using an ensemble of paediatric EEGs having the presence of epileptic seizure. The distinct spectral characteristics of global PDMs are found to be in line with the neural rhythms of brain dynamics. Moreover, we find that the linear trends of associated nonlinear functions (ANFs associated with the 2nd and 4th global PDMs (representing delta, theta and alpha bands of Fp1-F3 may differentiate between ictal and interictal states of epilepsy. These findings suggest that global PDMs and their associated ANFs may offer potential utility as diagnostic neural measures for ictal and interictal states of epilepsy.

  3. Muscle and eye movement artifact removal prior to EEG source localization.

    Science.gov (United States)

    Hallez, Hans; Vergult, Anneleen; Phlypo, Ronald; Van Hese, Peter; De Clercq, Wim; D'Asseler, Yves; Van de Walle, Rik; Vanrumste, Bart; Van Paesschen, Wim; Van Huffel, Sabine; Lemahieu, Ignace

    2006-01-01

    Muscle and eye movement artifacts are very prominent in the ictal EEG of patients suffering from epilepsy, thus making the dipole localization of ictal activity very unreliable. Recently, two techniques (BSS-CCA and pSVD) were developed to remove those artifacts. The purpose of this study is to assess whether the removal of muscle and eye movement artifacts improves the EEG dipole source localization. We used a total of 8 EEG fragments, each from another patient, first unfiltered, then filtered by the BSS-CCA and pSVD. In both the filtered and unfiltered EEG fragments we estimated multiple dipoles using RAP-MUSIC. The resulting dipoles were subjected to a K-means clustering algorithm, to extract the most prominent cluster. We found that the removal of muscle and eye artifact results to tighter and more clear dipole clusters. Furthermore, we found that localization of the filtered EEG corresponded with the localization derived from the ictal SPECT in 7 of the 8 patients. Therefore, we can conclude that the BSS-CCA and pSVD improve localization of ictal activity, thus making the localization more reliable for the presurgical evaluation of the patient.

  4. The early electroclinical manifestations of infantile spasms: A video EEG study

    Science.gov (United States)

    Iype, Mary; Kunju, Puthuvathra Abdul Mohammed; Saradakutty, Geetha; Mohan, Devi; Khan, Shahanaz Ahamed Mohammed

    2016-01-01

    Purpose: Infantile spasms are described as flexor extensor and mixed; but more features of their semiology and ictal electroencephalography (EEG) changes are sparse in the literature. The purpose of the study was to describe the clinical and ictal video-EEG characteristics of consecutive cases with infantile spasms and to try to find an association with the etiology. Materials and Methods: The clinical phenomenology and EEG characteristics on video-EEG were analyzed in 16 babies with infantile spasms. Results: A total of 869 spasms were reviewed. Nine (56.3%) showed focal seizures at least once during the recording and 1 (6.3%) had multifocal myoclonus in addition to the spasms. The duration of the cluster and interval between spasms was totally variable in all patients. Lateralizing phenomena were present in at least some of the spasms in all patients. Unilateral manual automatism in the form of holding the pinna was noted in three patients following the spasm. The ictal EEG activity in the majority (75%) was the slow wave. Four (25%) showed fast generalized spindle-like ictal discharges. Spikes, spike and wave activity, or electrodecremental pattern alone during the ictus was seen in none. On bivariate analysis, no factor noted on the video EEG had association with the etiology. Conclusion: Infantile spasms could be associated with focal and other seizures, has unique, non-uniform and variable semiology from patient to patient. The ictal EEG manifestation in the majority (75%) of our patients was the slow wave transient with 25% showing generalized fast spindle-like activity. PMID:27011629

  5. The early electroclinical manifestations of infantile spasms: A video EEG study

    Directory of Open Access Journals (Sweden)

    Mary Iype

    2016-01-01

    Full Text Available Purpose: Infantile spasms are described as flexor extensor and mixed; but more features of their semiology and ictal electroencephalography (EEG changes are sparse in the literature. The purpose of the study was to describe the clinical and ictal video-EEG characteristics of consecutive cases with infantile spasms and to try to find an association with the etiology. Materials and Methods: The clinical phenomenology and EEG characteristics on video-EEG were analyzed in 16 babies with infantile spasms. Results: A total of 869 spasms were reviewed. Nine (56.3% showed focal seizures at least once during the recording and 1 (6.3% had multifocal myoclonus in addition to the spasms. The duration of the cluster and interval between spasms was totally variable in all patients. Lateralizing phenomena were present in at least some of the spasms in all patients. Unilateral manual automatism in the form of holding the pinna was noted in three patients following the spasm. The ictal EEG activity in the majority (75% was the slow wave. Four (25% showed fast generalized spindle-like ictal discharges. Spikes, spike and wave activity, or electrodecremental pattern alone during the ictus was seen in none. On bivariate analysis, no factor noted on the video EEG had association with the etiology. Conclusion: Infantile spasms could be associated with focal and other seizures, has unique, non-uniform and variable semiology from patient to patient. The ictal EEG manifestation in the majority (75% of our patients was the slow wave transient with 25% showing generalized fast spindle-like activity.

  6. Evaluation of selected recurrence measures in discriminating pre-ictal and inter-ictal periods from epileptic EEG data

    International Nuclear Information System (INIS)

    Ngamga, Eulalie Joelle; Bialonski, Stephan; Marwan, Norbert; Kurths, Jürgen; Geier, Christian; Lehnertz, Klaus

    2016-01-01

    We investigate the suitability of selected measures of complexity based on recurrence quantification analysis and recurrence networks for an identification of pre-seizure states in multi-day, multi-channel, invasive electroencephalographic recordings from five epilepsy patients. We employ several statistical techniques to avoid spurious findings due to various influencing factors and due to multiple comparisons and observe precursory structures in three patients. Our findings indicate a high congruence among measures in identifying seizure precursors and emphasize the current notion of seizure generation in large-scale epileptic networks. A final judgment of the suitability for field studies, however, requires evaluation on a larger database. - Highlights: • Recurrence-based analysis of brain dynamics in human epilepsy. • Comparison of recurrence quantification and recurrence network measures. • Statistically significant precursory structures in three out of five patients. • High congruence among measures in characterizing brain dynamics.

  7. Evaluation of selected recurrence measures in discriminating pre-ictal and inter-ictal periods from epileptic EEG data

    Energy Technology Data Exchange (ETDEWEB)

    Ngamga, Eulalie Joelle [Potsdam Institute for Climate Impact Research, Telegraphenberg A 31, 14473 Potsdam (Germany); Bialonski, Stephan [Max-Planck-Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden (Germany); Marwan, Norbert, E-mail: marwan@pik-potsdam.de [Potsdam Institute for Climate Impact Research, Telegraphenberg A 31, 14473 Potsdam (Germany); Kurths, Jürgen [Potsdam Institute for Climate Impact Research, Telegraphenberg A 31, 14473 Potsdam (Germany); Department of Physics, Humboldt University Berlin, 12489 Berlin (Germany); Institute for Complex Systems and Mathematical Biology, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Geier, Christian [Department of Epileptology, University of Bonn, Sigmund-Freud-Straße 25, 53105 Bonn (Germany); Helmholtz Institute for Radiation and Nuclear Physics, University of Bonn, Nussallee 14–16, 53115 Bonn (Germany); Lehnertz, Klaus [Department of Epileptology, University of Bonn, Sigmund-Freud-Straße 25, 53105 Bonn (Germany); Helmholtz Institute for Radiation and Nuclear Physics, University of Bonn, Nussallee 14–16, 53115 Bonn (Germany); Interdisciplinary Center for Complex Systems, University of Bonn, Brühler Straße 7, 53175 Bonn (Germany)

    2016-04-01

    We investigate the suitability of selected measures of complexity based on recurrence quantification analysis and recurrence networks for an identification of pre-seizure states in multi-day, multi-channel, invasive electroencephalographic recordings from five epilepsy patients. We employ several statistical techniques to avoid spurious findings due to various influencing factors and due to multiple comparisons and observe precursory structures in three patients. Our findings indicate a high congruence among measures in identifying seizure precursors and emphasize the current notion of seizure generation in large-scale epileptic networks. A final judgment of the suitability for field studies, however, requires evaluation on a larger database. - Highlights: • Recurrence-based analysis of brain dynamics in human epilepsy. • Comparison of recurrence quantification and recurrence network measures. • Statistically significant precursory structures in three out of five patients. • High congruence among measures in characterizing brain dynamics.

  8. The usefulness of subtraction ictal SPECT and ictal near-infrared spectroscopic topography in patients with West syndrome.

    Science.gov (United States)

    Haginoya, Kazuhiro; Uematsu, Mitsugu; Munakata, Mitsutoshi; Kakisaka, Yosuke; Kikuchi, Atsuo; Nakayama, Tojo; Hino-Fukuyo, Naomi; Tsuburaya, Rie; Kitamura, Taro; Sato-Shirai, Ikuko; Abe, Yu; Matsumoto, Yoko; Wakusawa, Keisuke; Kobayashi, Tomoko; Ishitobi, Mamiko; Togashi, Noriko; Iwasaki, Masaki; Nakasato, Nobukazu; Iinuma, Kazuie

    2013-11-01

    The recent findings on subtraction ictal SPECT and ictal near-infrared spectroscopic topography in patients with West syndrome were summarized and its availability for presurgical evaluation was discussed. The subtraction ictal SPECT study in patients with West syndrome demonstrated the cortical epileptic region and subcortical involvement, which may consist of epilepsy networks related to the spasms. Moreover, subtraction ictal SPECT may have predictive power for short-term seizure outcome. Patients with a symmetric hyperperfusion pattern are predicted to have a better seizure outcome, whereas patients with asymmetric hyperperfusion pattern may develop poor seizure control. Importantly, asymmetric MRI findings had no predictive power for seizure outcome. Multichannel near-infrared spectroscopic topography applied to the patients with West syndrome detected an increase in regional cerebral blood volume in multiple areas which were activated either simultaneously or sequentially during spasms. Topographic changes in cerebral blood volume were closely correlated with spasm phenotype, suggesting that the cortex is involved in the generation of spasms. In conclusion, subtraction ictal SPECT may be considered as a useful tool for presurgical evaluation of patients with West syndrome and investigation of the pathophysiology of spasms. The ictal near-infrared spectroscopic topography should be more investigated to see if this is useful tool for presurgical evaluation. Copyright © 2013 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  9. Altered Rolandic gamma-band activation associated with motor impairment and ictal network desynchronization in childhood epilepsy.

    Directory of Open Access Journals (Sweden)

    Sam M Doesburg

    Full Text Available Epilepsy is associated with an abnormal expression of neural oscillations and their synchronization across brain regions. Oscillatory brain activation and synchronization also play an important role in cognition, perception and motor control. Childhood epilepsy is associated with a variety of cognitive and motor deficits, but the relationship between altered functional brain responses in various frequency ranges and functional impairment in these children remains poorly understood. We investigated functional magnetoencephalographic (MEG responses from motor cortex in multiple functionally relevant frequency bands following median nerve stimulation in twelve children with epilepsy, including four children with motor impairments. We demonstrated that children with motor impairments exhibit an excessive gamma-band response from Rolandic cortex, and that the magnitude of this Rolandic gamma response is negatively associated with motor function. Abnormal responses from motor cortex were also associated with ictal desynchronization of oscillations within Rolandic cortex measured using intracranial EEG (iEEG. These results provide the evidence that ictal disruption of motor networks is associated with an altered functional response from motor cortex, which is in turn associated with motor impairment.

  10. Induction of psychogenic nonepileptic events: success rate influenced by prior induction exposure, ictal semiology, and psychological profiles.

    Science.gov (United States)

    Chen, David K; Izadyar, Shahram; Collins, Robert L; Benge, Jared F; Lemaire, Ashley W; Hrachovy, Richard A

    2011-06-01

    To evaluate whether certain preinduction clinical characteristics may influence the success rate of induction. We prospectively enrolled and attempted inductions on 51 patients who were suspected to have psychogenic nonepileptic events based on clinical grounds. In addition to careful examination of the reported ictal semiology, we administered a battery of four psychological instruments to our enrolled patients. We found that among 42 cases of successful induction, 92.9% (n=39) of these cases were successfully induced on the first attempt (i.e., without prior induction exposure). We observed that induction showed significantly higher rate of success in cases that demonstrate: (1) hypermotor ictal semiology (p=0.029); (2) more prevalent self-reporting of uncommon cognitive and affective symptoms (p=0.035); or (3) higher tendency to rely on coping strategies of "instrumental support" (p=0.013) and "active coping" (p=0.027), when compared to noninducible cases. Singular administration of placebo induction on preselected patients with these clinical characteristics may reduce costs by shortening video electroencephalography-(EEG) monitoring sessions and improve the diagnostic yield of video-EEG even for patients with very infrequent events. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

  11. 'What is it?' A functional MRI and SPECT study of ictal speech in a second language

    International Nuclear Information System (INIS)

    Navarro, V.; Chauvire, V.; Baulac, M.; Cohen, L.; Delmaire, Ch.; Lehericy, St.; Habert, M.O.; Footnick, R.; Pallier, Ch.; Baulac, M.; Cohen, L.

    2009-01-01

    Neuronal networks involved in second language (L2) processing vary between normal subjects. Patients with epilepsy may have ictal speech automatisms in their second language. To delineate the brain systems involved in L2 ictal speech, we combined functional MRI during bilingual tasks and ictal - inter-ictal single-photon emission computed tomography in a patient who presented L2 ictal speech productions. These analyses showed that the networks activated by the seizure and those activated by L2 processing intersected in the right hippocampus. These results may provide some insights both into the pathophysiology of ictal speech and into the brain organization for L2. (authors)

  12. Age-specific Peri-ictal Electro-clinical Features of Generalized Tonic Clonic Seizures and Potential Risk of Sudden Unexpected Death in Epilepsy (SUDEP)

    Science.gov (United States)

    Freitas, Joel; Kaur, Gurmeen; Baca-Vaca Fernandez, Guadalupe; Tatsuoka, Curtis; Kaffashi, Farhad; Loparo, Kenneth A; Rao, Shyam; Loplumlert, Jakrin; Kaiboriboon, Kitti; Amina, Shahram; Tuxhorn, Ingrid; Lhatoo, Samden D

    2013-01-01

    Generalized tonic-clonic seizures (GTCS) are the commonest seizure type associated with Sudden Unexplained Death in Epilepsy (SUDEP). This study examines semiological and electroencephalographic differences (EEG) in the GTCS of adults as compared to children. The rationale lies in epidemiological observations that have noted a ten-fold higher incidence of SUDEP in adults. We analyzed video-EEG data of 105 GTCS in 61 consecutive patients (12 children, 23 seizures and 49 adults, 82 seizures) recruited from the Epilepsy Monitoring Unit. Semiological, EEG and 3-channel EKG features were studied. Peri-ictal seizure phase durations were analyzed including tonic, clonic, total seizure, post-ictal EEG suppression (PGES) and recovery phases. Heart rate variability (HRV) measures including RMSSD (root mean square successive difference of R-R intervals), SDNN (standard deviation of NN intervals) and SDSD (standard deviation of differences) were analyzed (including low frequency/high frequency power ratios) during pre-ictal baseline, ictal and post-ictal phases. Generalized estimating equations (GEE) were used to find associations between electro-clinical features. Separate subgroup analyses were carried out on adult and pediatric age groups as well as medication groups (no anti-epileptic medication cessation versus unchanged or reduced medication) during admission. Major differences were seen in adult and pediatric seizures with total seizure duration, tonic phase, PGES and recovery phases being significantly shorter in children (p<0.01). GEE analysis using tonic phase duration as the dependent variable, found age to correlate significantly (p<0.001) and this remained significant during subgroup analysis (adults and children) such that each 0.12 second increase in tonic phase duration correlated with a 1 second increase in PGES duration. PGES durations were on average 28 seconds shorter in children. With cessation of medication, total seizure duration was significantly

  13. [Brain lateralization and seizure semiology: ictal clinical lateralizing signs].

    Science.gov (United States)

    Horváth, Réka; Kalmár, Zsuzsanna; Fehér, Nóra; Fogarasi, András; Gyimesi, Csilla; Janszky, József

    2008-07-30

    Clinical lateralizing signs are the phenomena which can unequivocally refer to the hemispheric onset of epileptic seizures. They can improve the localization of epileptogenic zone during presurgical evaluation, moreover, their presence can predict a success of surgical treatment. Primary sensory phenomena such as visual aura in one half of the field of vision or unilateral ictal somatosensory sensation always appear on the contralateral to the focus. Periictal unilateral headache, although it is an infrequent symptom, is usually an ipsilateral sign. Primary motor phenomena like epileptic clonic, tonic movements, the version of head ubiquitously appear contralateral to the epileptogenic zone. Very useful lateralization sign is the ictal hand-dystonia which lateralizes to the contralateral hemisphere in nearly 100%. The last clonus of the secondarily generalized tonic-clonic seizure lateralizes to the ipsilateral hemisphere in 85%. The fast component of ictal nystagmus appears in nearly 100% on the contralateral side of the epileptic focus. Vegetative symptoms during seizures arising from temporal lobe such as spitting, nausea, vomiting, urinary urge are typical for seizures originating from non-dominant (right) hemisphere. Ictal pallor and cold shivers are dominant hemispheric lateralization signs. Postictal unilateral nose wiping refers to the ipsilateral hemispheric focus compared to the wiping hand. Ictal or postictal aphasia refers to seizure arising from dominant hemisphere. Intelligable speech during complex partial seizures appears in non-dominant seizures. Automatism with preserved consciousness refers to the seizures of non-dominant temporal lobe.

  14. Ictal technetium-99m ethyl cysteinate dimer single-photon emission tomographic findings and propagation of epileptic seizure activity in patients with extratemporal epilepsies

    International Nuclear Information System (INIS)

    Noachtar, S.; Arnold, S.; Werhahn, K.J.; Yousry, T.A.; Tatsch, K.

    1998-01-01

    We investigated the influence of the propagation of extratemporal epileptic seizure activity on the regional increase in cerebral blood flow, which is usually associated with epileptic seizure activity. Forty-two consecutive patients with extratemporal epilepsies were prospectively evaluated. All patients underwent ictal SPET studies with simultaneous electroencephalography (EEG) and video recordings of habitual seizures and imaging studies including cranial magnetic resonance imaging and positron emission tomography with 2-[ 18 F]-fluoro-2 deoxy-d-glucose. Propagation of epilptic seizure activity (PESA) was defined as the absence of hyperperfusion on ictal ECD SPET in the lobe of seizure onset, but its presence in another ipsilateral or contralateral lobe. Observers analysing the SPET images were not informed of the other results. PESA was observed in 8 of the 42 patients (19%) and was ipsilateral to the seizure onset in five (63%) of these eight patients. The time between clinical seizure onset and injection of the ECD tracer ranged from 14 to 61 s (mean 34 s). Seven patients (88%) with PESA had parieto-occipital epilepsy and one patient had a frontal epilepsy. PESA was statistically more frequent in patients with parieto-occipital lobe epilepsies (58%) than in the remaining extratemporal epilepsy syndromes (3%) (P<0.0002). These findings indicate that ictal SPET studies require simultaneous EEG-video recordings in patients with extratemporal epilepsies. PESA should be considered when interpreting ictal SPET studies in these patients. Patients with PESA are more likely to have parieto-occipital lobe epilepsy than seizure onset in other extratemporal regions. (orig./MG) (orig.)

  15. Ictal panic and interictal panic attacks: diagnostic and therapeutic principles.

    Science.gov (United States)

    Kanner, Andres M

    2011-02-01

    Ictal and postictal panic and interictal and primary panic attacks share common symptoms but differ with respect to duration and association with other symptoms. A careful history is often sufficient to distinguish these events. When necessary, electroencephalography and neuroimaging studies, estimation of prolactin levels can be a helpful tool in establishing an accurate diagnosis. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. EEG, MRI, and SPECT in epilepsy. Relative contributions to preoperative evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Seki, Gaku [Luoyang Medical Coll. Associated Hospital (China); Hoshida, Tohru; Goda, Kazuo; Hashimoto, Hiroshi; Nakase, Hiroyuki; Hirabayashi, Hidehiro; Kawaguchi, Shoichiro; Morimoto, Tetsuya; Sakaki, Toshisuke

    1998-07-01

    We comparatively assessed detection of epileptogenic areas on preoperative evaluation in 33 patients with intractable partial epilepsy using scalp interictal and ictal electroencephalography (EEG), magnetic resonance imaging (MRI), and interictal single photon emission computed tomography (SPECT). There are 22 temporal and 11 extratemporal lobe epilepsies. All or almost of their seizures have stopped after resective surgery for more than 12 months follow-up period, averaged 43 months. MRI studies demonstrated 21 organic lesions, 11 mesial temporal sclerosis and one patient showed normal brain tissue. Scalp EEG could correctly identify the focus in 14 of 33 cases (42%), interictal SPECT in 18 of 26 (69%), MRI in 29 of 33 (88%), interictal scalp EEG-video monitoring in 17 of 24 (71%), and ictal scalp EEG-video monitoring in 15 of 22 (68%). Although neuroimaging studies, especially MRI, are useful to detect not only localization of epileptic lesions but also epileptogenic focus, for example, mesial temporal sclerosis, the exact localization of epileptogenic areas could be done by comprehensive evaluation including ictal scalp EEG-video monitoring. (author)

  17. Epilepsy surgery in pediatric epileptic encephalopathy: when interictal EEG counts the most.

    Science.gov (United States)

    Shahwan, Amre; O'Halloran, Philip J; Madigan, Cathy; King, Mary D; O'Brien, Donncha

    2016-07-01

    Traditionally, seizure onset localization in ictal electro-encephalography (EEG) is the main factor guiding resective epilepsy surgery. The situation is often different in infantile epileptic encephalopathy. We demonstrate the importance of the underrated interictal (rather than ictal) surface EEG in informing decision-making in epilepsy surgery for children with epileptic encephalopathy caused by subtle focal cortical dysplasia (FCD). We present a small case series of three children who had an epileptic encephalopathy with either epileptic spasms or tonic seizures. All three were thought initially to have normal neuroimaging. Ictal EEG localizing features were seen in none and lateralizing features were seen only clinically in one of the three. However, the interictal EEG showed persistent and consistent focal irregular slowing in all, particularly after medically resolving the diffuse encephalopathy. Subtle FCDs were uncovered in all. Surgery was performed in all with excellent outcome. In infantile epileptic encephalopathy caused by subtle FCD, the often underrated interictal surface EEG (particularly persistent foal irregular slowing) informs the most; not only to the target area for surgical resection but also to its extent. This may negate the need for unnecessary and sometimes non-informative invasive monitoring in these cases. A matter of "zooming out" to define the extent of a resectable abnormality rather than "zooming in" to define a seemingly localized epileptic focus that may change with time.

  18. The additional lateralizing and localizing value of the postictal EEG in frontal lobe epilepsy.

    Science.gov (United States)

    Whitehead, Kimberley; Gollwitzer, Stephanie; Millward, Helen; Wehner, Tim; Scott, Catherine; Diehl, Beate

    2016-03-01

    The aim of this study was to describe the additional lateralizing and localizing value of the postictal EEG in frontal lobe epilepsy (FLE). The ictal EEG in FLE is frequently challenging to localize. We identified patients investigated for epilepsy surgery with unilateral FLE based on consistent semiology, a clear lesion and/or with frontal onset on intracranial EEG. A one hour section of postictal EEG was analyzed by two raters for new or activated EEG features and it was assessed whether these features offered additional information when compared to the ictal EEG. Postictal features assessed included asymmetrical return of the posterior dominant rhythm and potentiated lateralized or regional frontal slowing, spikes or sharp waves. Thirty-eight patients were included who had a combined total of ninety-six seizures. 47/96 (49%) postictal periods contained correctly lateralizing or localizing information. The sensitivity for asymmetrical return of the posterior dominant rhythm was 24%. The sensitivity for regional frontal slow and frontal spikes was 23% and 20% respectively. Further analysis showed that in 14/38 (39%) patients, at least one seizure with an unhelpful ictal EEG was followed by postictal EEG features that added new localizing or lateralizing information. A subgroup of 11 patients who were ⩾1 year seizure-free (ILAE class 1) and thus classified as having a 'gold-standard' FLE diagnosis were analyzed separately and it was found that 14/30 of their seizures (47%) had extra postictal information. The new postictal information was always concordant with the ultimate diagnosis, except for asymmetric postictal return of background activity ipsilateral to the epileptogenic zone in three patients. This study shows that a close examination of the postictal EEG can offer additional information which can contribute to the identification of a potentially resectable epileptogenic zone. Copyright © 2015 International Federation of Clinical Neurophysiology

  19. Similar semiology of epileptic and psychogenic nonepileptic seizures recorded during stereo-EEG.

    Science.gov (United States)

    Ostrowsky-Coste, Karine; Montavont, Alexandra; Keo-Kosal, Pascale; Guenot, Marc; Chatillon, Claude-Edouard; Ryvlin, Philippe

    2013-12-01

    We report two adolescents with refractory seizure disorders in whom both epileptic and psychogenic nonepileptic seizures (PNES) were recorded with intracerebral EEG. The ictal phenomenology of epileptic seizures (ES) and PNES, consisting of hypermotor attacks in the first patient and left-sided painful episodes in the second patient, proved remarkably similar in both cases, highlighting the difficulties which can arise with the distinction of epileptic seizures and PNES based on ictal phenomenology alone. Copyright © 2013 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  20. Infraslow EEG changes in infantile spasms.

    Science.gov (United States)

    Myers, Kenneth A; Bello-Espinosa, Luis E; Wei, Xing-Chang; Scantlebury, Morris H

    2014-12-01

    Infantile spasms (IS) are a devastating epileptic encephalopathy syndrome of infancy. Analysis of infraslow EEG activity (ISA) has shown potential in the presurgical evaluation of patients with epilepsy and in differentiating between focal and generalized epilepsy syndromes. Infraslow EEG activity analysis may provide insights into the pathophysiology of some difficult-to-treat epilepsy syndromes, such as IS. To our knowledge, there are no published reports describing ISA in patients with IS. The purpose of this study was to describe ictal patterns of ISA in patients with IS and to correlate with clinical data. EEG recordings of all cases of IS in the past 10 years at the Alberta Children's Hospital were reviewed. Inclusion criteria were a technically adequate video EEG recording that captured at least one spasm. For each patient, the first 10 confirmed spasms were examined. Spasms were evaluated for changes in ISA, which were either generalized, lateralized, or absent ISA (g-ISA, l-ISA, or n-ISA, respectively). Results were correlated with treatments, clinical course, and information pertinent to likely etiology of the IS. A total of 77% of spasms were associated with ISA; 57% with g-ISA, 20% l-ISA, and 21% n-ISA. All patients with exclusively g-ISA showed at least a partial response to initial therapy, while this was the case in 66.7% of those with at least some l-ISA and 50% of those with exclusively n-ISA. Other seizure types occurred in 60% of patients with exclusively g-ISA versus 83% with some l-ISA and all patients with exclusively n-ISA. Ictal ISA was observed in the majority of IS. Trends were observed suggesting that the presence of exclusive g-ISA changes may be a positive prognostic factor in IS.

  1. Vomiting as an ictal manifestation of epileptic seizures and syndromes.

    Science.gov (United States)

    Panayiotopoulos, C P

    1988-01-01

    Twenty-four out of 900 adult and children patients with epilepsy, were found to have vomiting during an ictus. All the 24 patients were children before puberty with a similar clinical pattern consisting of partial seizures which were mainly nocturnal. Ictal vomiting was always concurrent with other epileptic manifestations, more often deviation of the eyes and impairment of consciousness. The initial part of the ictus was short or prolonged for hours with frequent "marching" to hemi-convulsions and generalised seizures. Seventeen of the 24 children suffered from benign childhood epilepsies (BCE) with complete remission in long follow-up. A significantly higher association was found between ictal vomiting and the syndrome of BCE with occipital spikes (p less than 0.001) but not with centro-temporal spikes (p less than 0.2). The recognition of this association may have important theoretical implications. On clinical grounds, it may prevent unnecessary investigations and undue concern. PMID:3148690

  2. Automatic ictal HFO detection for determination of initial seizure spread.

    Science.gov (United States)

    Graef, Andreas; Flamm, Christoph; Pirker, Susanne; Baumgartner, Christoph; Deistler, Manfred; Matz, Gerald

    2013-01-01

    High-frequency oscillations (HFOs) are a reliable indicator for the epileptic seizure onset zone (SOZ) in ECoG recordings. We propose a novel method for the automatic detection of ictal HFOs in the ripple band (80-250 Hz) based on CFAR matched sub-space filtering. This allows to track the early propagation of ictal HFOs, revealing initial and follow-up epileptic activity on the electrodes. We apply this methodology to two seizures from one patient suffering from focal epilepsy. The electrodes identified are in very good accordance with the visual HFO analysis by clinicians. Furthermore the electrodes with initial HFO activity are correlated well with the SOZ (conventional v-activity).

  3. 'What is it?' A functional MRI and SPECT study of ictal speech in a second language

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, V.; Chauvire, V.; Baulac, M.; Cohen, L. [Department of Neurology, AP-HP, Hopital de la Pitie-Salpetriere, IFR 70, Paris (France); Delmaire, Ch.; Lehericy, St. [Department of Neuroradiology, AP-HP, Hopital de la Pitie-Salpetriere, IFR 70, Paris (France); Habert, M.O. [Department of Nuclear Medicine, AP-HP, Hopital de la Pitie-Salpetriere, IFR 70, Paris (France); Footnick, R.; Pallier, Ch. [INSERM, U562, CEA/DSV, IFR 49, Orsay (France); Baulac, M.; Cohen, L. [Universite Paris VI, Faculte Pitie-Salpetriere, Paris (France)

    2009-07-01

    Neuronal networks involved in second language (L2) processing vary between normal subjects. Patients with epilepsy may have ictal speech automatisms in their second language. To delineate the brain systems involved in L2 ictal speech, we combined functional MRI during bilingual tasks and ictal - inter-ictal single-photon emission computed tomography in a patient who presented L2 ictal speech productions. These analyses showed that the networks activated by the seizure and those activated by L2 processing intersected in the right hippocampus. These results may provide some insights both into the pathophysiology of ictal speech and into the brain organization for L2. (authors)

  4. The cortical focus in childhood absence epilepsy; evidence from nonlinear analysis of scalp EEG recordings.

    Science.gov (United States)

    Sarrigiannis, Ptolemaios G; Zhao, Yifan; He, Fei; Billings, Stephen A; Baster, Kathleen; Rittey, Chris; Yianni, John; Zis, Panagiotis; Wei, Hualiang; Hadjivassiliou, Marios; Grünewald, Richard

    2018-03-01

    To determine the origin and dynamic characteristics of the generalised hyper-synchronous spike and wave (SW) discharges in childhood absence epilepsy (CAE). We applied nonlinear methods, the error reduction ratio (ERR) causality test and cross-frequency analysis, with a nonlinear autoregressive exogenous (NARX) model, to electroencephalograms (EEGs) from CAE, selected with stringent electro-clinical criteria (17 cases, 42 absences). We analysed the pre-ictal and ictal strength of association between homologous and heterologous EEG derivations and estimated the direction of synchronisation and corresponding time lags. A frontal/fronto-central onset of the absences is detected in 13 of the 17 cases with the highest ictal strength of association between homologous frontal followed by centro-temporal and fronto-central areas. Delays consistently in excess of 4 ms occur at the very onset between these regions, swiftly followed by the emergence of "isochronous" (0-2 ms) synchronisation but dynamic time lag changes occur during SW discharges. In absences an initial cortico-cortical spread leads to dynamic lag changes to include periods of isochronous interhemispheric synchronisation, which we hypothesize is mediated by the thalamus. Absences from CAE show ictal epileptic network dynamics remarkably similar to those observed in WAG/Rij rats which guided the formulation of the cortical focus theory. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  5. Epileptic seizure detection from EEG signals with phase-amplitude cross-frequency coupling and support vector machine

    Science.gov (United States)

    Liu, Yang; Wang, Jiang; Cai, Lihui; Chen, Yingyuan; Qin, Yingmei

    2018-03-01

    As a pattern of cross-frequency coupling (CFC), phase-amplitude coupling (PAC) depicts the interaction between the phase and amplitude of distinct frequency bands from the same signal, and has been proved to be closely related to the brain’s cognitive and memory activities. This work utilized PAC and support vector machine (SVM) classifier to identify the epileptic seizures from electroencephalogram (EEG) data. The entropy-based modulation index (MI) matrixes are used to express the strength of PAC, from which we extracted features as the input for classifier. Based on the Bonn database, which contains five datasets of EEG segments obtained from healthy volunteers and epileptic subjects, a 100% classification accuracy is achieved for identifying seizure ictal from healthy data, and an accuracy of 97.67% is reached in the classification of ictal EEG signals from inter-ictal EEGs. Based on the CHB-MIT database which is a group of continuously recorded epileptic EEGs by scalp electrodes, a 97.50% classification accuracy is obtained and a raising sign of MI value is found at 6s before seizure onset. The classification performance in this work is effective, and PAC can be considered as a useful tool for detecting and predicting the epileptic seizures and providing reference for clinical diagnosis.

  6. Dynamic Principal Component Analysis with Nonoverlapping Moving Window and Its Applications to Epileptic EEG Classification

    Directory of Open Access Journals (Sweden)

    Shengkun Xie

    2014-01-01

    Full Text Available Classification of electroencephalography (EEG is the most useful diagnostic and monitoring procedure for epilepsy study. A reliable algorithm that can be easily implemented is the key to this procedure. In this paper a novel signal feature extraction method based on dynamic principal component analysis and nonoverlapping moving window is proposed. Along with this new technique, two detection methods based on extracted sparse features are applied to deal with signal classification. The obtained results demonstrated that our proposed methodologies are able to differentiate EEGs from controls and interictal for epilepsy diagnosis and to separate EEGs from interictal and ictal for seizure detection. Our approach yields high classification accuracy for both single-channel short-term EEGs and multichannel long-term EEGs. The classification performance of the method is also compared with other state-of-the-art techniques on the same datasets and the effect of signal variability on the presented methods is also studied.

  7. The study of ictal brain SPECT during seizures induced by clonidine and sleep-deprivation in patients with epilepsy

    International Nuclear Information System (INIS)

    Wang Xiaohui; Chen Xuehong; Wang Zhengjiang; Liu Jiangyan; Feng Jianzhong; Ye Jiang; Zhao Li

    2010-01-01

    Objective: To evaluate the feasibility and clinical value of combined clonidine and sleep-deprivation induced seizures for ictal brain SPECT imaging in patients with epilepsy. Methods: Fifty-two epilepsy patients were given oral clonidine plus sleep-deprivation to induce seizures with video-electroencephalogram (VEEG) monitoring. Forty-seven patients were selected as control group, whose seizures were induced by sleep-deprivation only. 99 Tc m -ethylcysteinate dimer (ECD) was injected within 30 s since a clinical sign and/or a typical EEG discharge of epilepsy was recognized. Brain SPECT was performed 30 min after 99 Tc m -ECD injection. χ 2 -test was performed by using software SPSS 10.0. Results: One to two hr after oral intake of clonidine plus sleep-deprivation, 75% (39/52) patients were induced seizures, including 92.3% (36/39) with subclinical seizures and 7.7% (3/39) with clinical seizures. Ictal brain SPECT localized the lesions with high uptake of 99 Tc m -ECD in 37 (94.9%) patients. In control group, 38.3% (18/47) were induced epileptic seizures, including 77.8% (14/18) with subclinical seizures and 22.2% (4/18) with clinical seizures. The induction rate of epileptic seizures in clonidine plus sleep-deprivation group was significantly higher than that of control group (χ 2 = 13.614, P 2 = 1.253, P>0.05). Conclusions: The combination of oral intake of clonidine and sleep-deprivation could increase the induction rate of epileptic seizures and it is effective for epilepsy SPECT imaging. (authors)

  8. Rhythmic EEG patterns in extremely preterm infants: Classification and association with brain injury and outcome.

    Science.gov (United States)

    Weeke, Lauren C; van Ooijen, Inge M; Groenendaal, Floris; van Huffelen, Alexander C; van Haastert, Ingrid C; van Stam, Carolien; Benders, Manon J; Toet, Mona C; Hellström-Westas, Lena; de Vries, Linda S

    2017-12-01

    Classify rhythmic EEG patterns in extremely preterm infants and relate these to brain injury and outcome. Retrospective analysis of 77 infants born position. No relation was found between the median total duration of each pattern and injury on cUS and MRI or cognition at 2 and 5 years. Clear ictal discharges are rare in extremely preterm infants. PEDs are common but their significance is unclear. Rhythmic waveforms related to head position are likely artefacts. Rhythmic EEG patterns may have a different significance in extremely preterm infants. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  9. Multichannel EEG Visualization

    NARCIS (Netherlands)

    Caat, Michael ten

    2008-01-01

    Electroencephalography (EEG) measures electrical brain activity by electrodes attached to the scalp. Multichannel EEG refers to a measurement with a large number of electrodes. EEG has clinical as well as scientific applications, including neurology, psychology, pharmacy, linguistics, and biology.

  10. Epilepsy-induced behavioral changes during the ictal phase.

    Science.gov (United States)

    Mula, Marco

    2014-01-01

    In epilepsy, experiential phenomena and behavioral manifestations may pose a number of problems in terms of differential diagnosis. From a clinical point of view, ictal psychiatric symptoms represent partial seizures, mainly partial ones. In the majority of cases, they are very brief (lasting from a few seconds to a few minutes), stereotyped, out of context, and frequently associated with subtle or overt automatisms and postictal confusion of variable duration. In some cases, such symptoms are followed by alteration of consciousness as the ictus evolves to a complex partial seizure or a generalized tonic-clonic seizure. This paper reviews clinically relevant behavioral patterns during seizures discussing clinical phenomenology and relevance in terms of lateralizing value. © 2013.

  11. {sup 1}H MR spectroscopic imaging in patients with MRI-negative extratemporal epilepsy: correlation with ictal onset zone and histopathology

    Energy Technology Data Exchange (ETDEWEB)

    Krsek, Pavel; Komarek, Vladimir [Charles University, Department of Pediatric Neurology, Second Medical School, Motol Hospital, Prague (Czech Republic); Hajek, Milan [Institute for Clinical and Experimental Medicine, MR Unit, Department of Diagnostic and Interventional Radiology, Prague (Czech Republic); Institute for Clinical and Experimental Medicine, MR Spectroscopy, Prague 4 (Czech Republic); Dezortova, Monika; Jiru, Filip; Skoch, Antonin [Institute for Clinical and Experimental Medicine, MR Unit, Department of Diagnostic and Interventional Radiology, Prague (Czech Republic); Marusic, Petr [Charles University, Department of Neurology, Second Medical School, Motol Hospital, Prague (Czech Republic); Zamecnik, Josef [Charles University, Department of Pathology and Molecular Medicine, Second Medical School, Motol Hospital, Prague (Czech Republic); Kyncl, Martin [Charles University, Department of Radiology, Second Medical School, Motol Hospital, Prague (Czech Republic); Tichy, Michal [Charles University, Department of Pediatric Neurosurgery, Second Medical School, Motol Hospital, Prague (Czech Republic)

    2007-08-15

    Proton magnetic resonance spectroscopy ({sup 1}H MRS) is beneficial in the lateralization of the epileptogenic zone in temporal lobe epilepsy; however, its role in extratemporal and, especially, MRI-negative epilepsy has not been established. This study seeks to verify how {sup 1}H MRS could help in localizing the epileptogenic zone in patients with MRI-negative extratemporal epilepsy. Seven patients (8-23 years) with MRI-negative refractory focal epilepsy were studied using {sup 1}H MRS on a 1.5T MR system. Chemical shift imaging sequence in the transversal plane was directed towards the suspected epileptogenic zone localized by seizure semiology, scalp video/EEG, ictal SPECT and {sup 18}FDG-PET. Spectra were evaluated using the program CULICH, and the coefficient of asymmetry was used for quantitative lateralization. MRS detected lateralization in all patients and was able to localize pathology in five. The most frequent findings were decreased ratios of N-acetylaspartate to choline compounds characterized by increasing choline concentration. The localization of the {sup 1}H MRS abnormality correlated well with ictal SPECT and subdural mapping. In all cases, histopathological analysis revealed MRI-undetected focal cortical dysplasias. {sup 1}H MRS could be more sensitive for the detection of discrete malformations of cortical development than conventional MRI. It is valuable in the presurgical evaluation of patients without MRI-apparent lesions. (orig.)

  12. Seizure classification in EEG signals utilizing Hilbert-Huang transform.

    Science.gov (United States)

    Oweis, Rami J; Abdulhay, Enas W

    2011-05-24

    Classification method capable of recognizing abnormal activities of the brain functionality are either brain imaging or brain signal analysis. The abnormal activity of interest in this study is characterized by a disturbance caused by changes in neuronal electrochemical activity that results in abnormal synchronous discharges. The method aims at helping physicians discriminate between healthy and seizure electroencephalographic (EEG) signals. Discrimination in this work is achieved by analyzing EEG signals obtained from freely accessible databases. MATLAB has been used to implement and test the proposed classification algorithm. The analysis in question presents a classification of normal and ictal activities using a feature relied on Hilbert-Huang Transform. Through this method, information related to the intrinsic functions contained in the EEG signal has been extracted to track the local amplitude and the frequency of the signal. Based on this local information, weighted frequencies are calculated and a comparison between ictal and seizure-free determinant intrinsic functions is then performed. Methods of comparison used are the t-test and the Euclidean clustering. The t-test results in a P-value method is also contrasted against the Multivariate Empirical Mode Decomposition that reaches 80% accuracy. Comparison results strengthen the contribution of this paper not only from the accuracy point of view but also with respect to its fast response and ease to use. An original tool for EEG signal processing giving physicians the possibility to diagnose brain functionality abnormalities is presented in this paper. The proposed system bears the potential of providing several credible benefits such as fast diagnosis, high accuracy, good sensitivity and specificity, time saving and user friendly. Furthermore, the classification of mode mixing can be achieved using the extracted instantaneous information of every IMF, but it would be most likely a hard task if only the

  13. Seizure classification in EEG signals utilizing Hilbert-Huang transform

    Directory of Open Access Journals (Sweden)

    Abdulhay Enas W

    2011-05-01

    Full Text Available Abstract Background Classification method capable of recognizing abnormal activities of the brain functionality are either brain imaging or brain signal analysis. The abnormal activity of interest in this study is characterized by a disturbance caused by changes in neuronal electrochemical activity that results in abnormal synchronous discharges. The method aims at helping physicians discriminate between healthy and seizure electroencephalographic (EEG signals. Method Discrimination in this work is achieved by analyzing EEG signals obtained from freely accessible databases. MATLAB has been used to implement and test the proposed classification algorithm. The analysis in question presents a classification of normal and ictal activities using a feature relied on Hilbert-Huang Transform. Through this method, information related to the intrinsic functions contained in the EEG signal has been extracted to track the local amplitude and the frequency of the signal. Based on this local information, weighted frequencies are calculated and a comparison between ictal and seizure-free determinant intrinsic functions is then performed. Methods of comparison used are the t-test and the Euclidean clustering. Results The t-test results in a P-value Conclusion An original tool for EEG signal processing giving physicians the possibility to diagnose brain functionality abnormalities is presented in this paper. The proposed system bears the potential of providing several credible benefits such as fast diagnosis, high accuracy, good sensitivity and specificity, time saving and user friendly. Furthermore, the classification of mode mixing can be achieved using the extracted instantaneous information of every IMF, but it would be most likely a hard task if only the average value is used. Extra benefits of this proposed system include low cost, and ease of interface. All of that indicate the usefulness of the tool and its use as an efficient diagnostic tool.

  14. MRI in temporal lobe epilepsy. Correlation between EEG, SPECT and clinical features

    International Nuclear Information System (INIS)

    Uesugi, Hideji; Onuma, Teiichi; Matsuda, Hiroshi; Ishida, Shiro

    1996-01-01

    The relationship between MRI, SPECT, EEG and clinical features in temporal lobe epilepsy was investigated. Subjects were 162 patients (84 males, 78 females) whose average age was 38.1±12.1 years. SPECT was carried out in 45 patients. The results were as follows: abnormal MR images were obtained in 36% of the group without epileptic discharge, and in 42% of the group with temporal spikes. There was no correlation between epileptic discharge in EEG and MRI abnormality. The lateralities of epileptic discharge and MRI were in disagreement in 9 of 39 patients (23%), indicating that determining the epileptic focus from scalp EEG was difficult. There was no correlation between the basic activity in EEG and abnormality in MRI. The rate of abnormal SPECT (89%) was higher than that of abnormal MRI (40%). The rate of the group with ictal automatism (52%) was higher than that of the group without ictal automatism (35%). The rate of abnormal MR images was high in the group with encephalitis (73%). The rate was higher in the group with febrile convulsion (62%) than in the group without it (28%). The rate of the abnormal MR images was higher in the group with a seizure frequency of at least several mal/month (48%) than in the group with a seizure frequency of less than several mal/year (29%). (author)

  15. Proposal for best practice in the use of video-EEG when psychogenic non-epileptic seizures are a possible diagnosis

    Directory of Open Access Journals (Sweden)

    Kimberley Whitehead

    Full Text Available The gold-standard for the diagnosis of psychogenic non-epileptic seizures (PNES is capturing an attack with typical semiology and lack of epileptic ictal discharges on video-EEG. Despite the importance of this diagnostic test, lack of standardisation has resulted in a wide variety of protocols and reporting practices. The goal of this review is to provide an overview of research findings on the diagnostic video-EEG procedure, in both the adult and paediatric literature. We discuss how uncertainties about the ethical use of suggestion can be resolved, and consider what constitutes best clinical practice. We stress the importance of ictal observation and assessment and consider how diagnostically useful information is best obtained. We also discuss the optimal format of video-EEG reports; and of highlighting features with high sensitivity and specificity to reduce the risk of miscommunication. We suggest that over-interpretation of the interictal EEG, and the failure to recognise differences between typical epileptic and nonepileptic seizure manifestations are the greatest pitfalls in neurophysiological assessment of patients with PNES. Meanwhile, under-recognition of semiological pointers towards frontal lobe seizures and of the absence of epileptiform ictal EEG patterns during some epileptic seizure types (especially some seizures not associated with loss of awareness, may lead to erroneous PNES diagnoses. We propose that a standardised approach to the video-EEG examination and the subsequent written report will facilitate a clear communication of its import, improving diagnostic certainty and thereby promoting appropriate patient management. Keywords: Psychogenic nonepileptic seizures, Nonepileptic attack disorder, Suggestion, EEG

  16. Meditation and the EEG

    OpenAIRE

    West, Michael

    1980-01-01

    Previous research on meditation and the EEG is described, and findings relating to EEG patterns during meditation are discussed. Comparisons of meditation with other altered states are reviewed and it is concluded that, on the basis of existing EEG evidence, there is some reason for differentiating between meditation and drowsing. Research on alpha-blocking and habituation of the blocking response during meditation is reviewed, and the effects of meditation on EEG patterns outside of meditati...

  17. Mobile EEG in epilepsy

    NARCIS (Netherlands)

    Askamp, Jessica; van Putten, Michel Johannes Antonius Maria

    2014-01-01

    The sensitivity of routine EEG recordings for interictal epileptiform discharges in epilepsy is limited. In some patients, inpatient video-EEG may be performed to increase the likelihood of finding abnormalities. Although many agree that home EEG recordings may provide a cost-effective alternative

  18. Intracranial EEG in predicting surgical outcome in frontal lobe epilepsy.

    Science.gov (United States)

    Holtkamp, Martin; Sharan, Ashwini; Sperling, Michael R

    2012-10-01

    Surgery in frontal lobe epilepsy (FLE) has a worse prognosis regarding seizure freedom than anterior lobectomy in temporal lobe epilepsy. The current study aimed to assess whether intracranial interictal and ictal EEG findings in addition to clinical and scalp EEG data help to predict outcome in a series of patients who needed invasive recording for FLE surgery. Patients with FLE who had resective surgery after chronic intracranial EEG recording were included. Outcome predictors were compared in patients with seizure freedom (group 1) and those with recurrent seizures (group 2) at 19-24 months after surgery. Twenty-five patients (16 female) were included in this study. Mean age of patients at epilepsy surgery was 32.3 ± 15.6 years (range 12-70); mean duration of epilepsy was 16.9 ± 13.4 years (range 1-48). In each outcome group, magnetic resonance imaging revealed frontal lobe lesions in three patients. Fifteen patients (60%) were seizure-free (Engel class 1), 10 patients (40%) continued to have seizures (two were class II, three were class III, and five were class IV). Lack of seizure freedom was seen more often in patients with epilepsy surgery on the left frontal lobe (group 1, 13%; group 2, 70%; p = 0.009) and on the dominant (27%; 70%; p = 0.049) hemisphere as well as in patients without aura (29%; 80%; p = 0.036), whereas sex, age at surgery, duration of epilepsy, and presence of an MRI lesion in the frontal lobe or extrafrontal structures were not different between groups. Electroencephalographic characteristics associated with lack of seizure freedom included presence of interictal epileptiform discharges in scalp recordings (31%; 90%; p = 0.01). Detailed analysis of intracranial EEG revealed widespread (>2 cm) (13%; 70%; p = 0.01) in contrast to focal seizure onset as well as shorter latency to onset of seizure spread (5.8 ± 6.1 s; 1.5 ± 2.3 s; p = 0.016) and to ictal involvement of brain structures beyond the frontal lobe (23.5 ± 22.4 s; 5.8 ± 5.4 s

  19. Cardiac arrest associated with epileptic seizures: A case report with simultaneous EEG and ECG

    Directory of Open Access Journals (Sweden)

    Jafar Mehvari

    2014-01-01

    Full Text Available Ictal asystole is a rare, probably underestimated manifestation of epileptic seizures whose pathophysiology is still debated. This report describes two patients who had cardiac asystole at the end of their seizure. The first patient was a 13-year-old boy with complex partial seizures.. His MRI showed symmetrical signal abnormality in the bilateral parietooccipital lobe accompanied by mild gliosis and volume loss. During a 3-day long-term video-EEG monitoring, he had cardiac arrest at the end of one of his seizures that was secondarily generalized. The second one was a 42-year-old veteran with penetrating head trauma in the left frontal lobe due to shell injury. During long-term video-EEG monitoring, he had one generalized tonic–clonic seizure accompanied by bradycardia and cardiac asystole. Asystoles could have a role in the incidence of sudden unexpected death in epilepsy (SUDEP, meaning that the presence of ictal bradycardia is a risk factor for SUDEP. In cases of epileptic cardiac dysrhythmia, prolonged simultaneous EEG/ECG monitoring may be required. Cardiological investigation should be included in epilepsy management.

  20. Ictal asystole: A rare cardiac manifestation of temporal lobe epilepsy, treated with epilepsy surgery.

    Science.gov (United States)

    Ravat, Shreyas Hasmukh; Bhatti, Amit Ashok; Shah, Mansi Viraj; Muzumdar, Dattatraya P; Ravat, Sangeeta Hasmukh

    2017-01-01

    Seizures are associated with fascinatingly varied cardiac and autonomic manifestations, of which ictal tachycardia is common, and asystole and bradycardia are rare. Ictal asystole (IA), an often unsought autonomic phenomenon, occurs most commonly with temporal followed by frontal lobe seizures. Prolonged IA may lead to cerebral anoxic ischemia. As the mysteries of sudden unexplained death in epilepsy are unraveled, it is quite possible that the key to it lays within these seizure-induced cardiac rhythm abnormalities. We present a case of a young male with temporal lobe epilepsy due to left mesial temporal sclerosis with prolonged IA, which was successfully managed with epilepsy surgery.

  1. Population of the ictal-interictal zone: The significance of periodic and rhythmic activity

    Directory of Open Access Journals (Sweden)

    Emily L. Johnson

    Full Text Available Seizures contribute to patient mortality and are usually treated aggressively. Rhythmic and periodic patterns – the “ictal-interictal continuum” – are often associated with seizures, yet the optimum method of treating these patterns is not known: should they be aggressively suppressed, or monitored without treatment? Understanding which patterns are more strongly associated with seizures and which are highly associated with mortality is important to help the clinician decide how to treat these findings. We present an overview of the etiologies, association with seizures, and mortality of periodic and rhythmic patterns, and one approach to treatment. Keywords: Ictal-interictal continuum, Periodic discharges, Rhythmic delta activity

  2. Effects of epileptiform EEG discharges on cognitive function: is the concept of "transient cognitive impairment" still valid?

    Science.gov (United States)

    Aldenkamp, Albert P; Arends, Johan

    2004-02-01

    In this article we review the existing evidence on the cognitive impact of interictal epileptiform EEG discharges. Such cognitive impairment occurs exclusively in direct relation to episodes of epileptiform EEG discharges and must be distinguished from (post) ictal seizure effects and from the nonperiodic long-term "stable" interictal effects caused by the clinical syndrome or the underlying etiology. Especially in patients with short nonconvulsive seizures, characterized often by difficult-to-detect symptoms, the ictal or postictal effects may be overlooked and the resulting cognitive effects may be erroneously related to the epileptiform EEG discharges. The existing epidemiological data show that the prevalence of cognitive impairment during epileptiform EEG discharges is low. In one study 2.2% of the patients referred to a specialized epilepsy center for EEG recording showed a definite relationship between epileptiform EEG discharges and cognitive impairments ("transient cognitive impairment"). Several studies have sought to analyze to what extent cognitive impairment can be attributed to epileptiform EEG discharges among the other epilepsy factors (such as the effect of the clinical syndrome). These studies show that epileptiform EEG discharges have an additional and independent effect, but this effect is mild and limited to transient mechanistic cognitive processes (alertness, mental speed). This finding concurs with clinical studies that also reported only mild effects. In only exceptional cases are epileptiform EEG discharges the dominant factor explaining cognitive impairment. In addition, some studies have indicated that such mild effects may accumulate over time (when frequent epileptiform EEG discharges persist over years) and consequently result in effects on stable aspects of cognitive function such as educational achievement and intelligence. Hence, the clinical relevance is that early detection of cognitive effects of epileptiform EEG discharges and

  3. Impact of ictal/postictal regional cerebral blood flow patterns on the management of patients with complex partial seizures

    International Nuclear Information System (INIS)

    Borbely, K.; Toth, M.; Solyom, A.; Balogh, A.; Juhos, V.; Neuwirth, M.; Halasz, P.

    2002-01-01

    Aims: RCBF SPECT has been proved to be a sensitive and specific method in the pre-surgical evaluation of patients with complex partial seizures (CPS). Ictal minus interictal rCBF analysis is a routine part in the assessment of epileptogenic foci. During ictal/postictal rCBF studies changes might appear not only in the epileptogenic area. The precise note of the time of the tracer injection for SPECT is the key in interpreting the brain perfusion changes. We studied ictal/postictal rCBF patterns in the brain tissue within, adjacent to, and remote from the epileptogenic foci in 64 patients with CPS. Methods: The assessment included neurological examination, ictal semiology, interictal and ictal electrophysiological recording, MRI, and neuropsychological evaluation. Baseline, ictal and/or postictal SPECT studies were carried out with a standard technique for each patient. SPECT data were analysed visually and by a special region of interests (ROIs) program. Circular ROIs were placed over the basal ganglia, thalamus, frontal, temporal, parietal, occipital cortex, and cerebellum. ROIs were normalized to the whole brain average. The statistical analysis was considered significant at P<0.05. MRI was positive in 46 patients, while in 18 cases there were no abnormalities. SPECT results were compared to electrophysiological and surgical findings. Results: The baseline SPECT demonstrated a significant hypoperfusion (P<0.05) in the epileptogenic area (EA) in 37/64 (57.81%) cases. 54/64 (84.38%) of the ictal studies showed a marked hyperperfusion (P<0.005) in the EA with low cerebellar tracer uptake (P<0.05). In 26/64 (40.63%) patients the early postictal studies demonstrated moderate or high tracer uptake in the EA (P<0.05) with diffuse perfusion abnormalities in the surrounding tissue. Late postictal studies (14/64, 21.88%) showed hypoperfusion (P<0.05) in the EA with moderate or high tracer uptake in the surrounding tissue. The results of the ictal/postictal studies

  4. EEG: Origin and measurement

    NARCIS (Netherlands)

    Lopes da Silva, F.; Mulert, C.; Lemieux, L.

    2010-01-01

    The existence of the electrical activity of the brain (i.e. the electroencephalogram or EEG) was discovered more than a century ago by Caton. After the demonstration that the EEG could be recorded from the human scalp by Berger in the 1920s, it made a slow start before it became accepted as a method

  5. Epileptic fast intracerebral EEG activity: evidence for spatial decorrelation at seizure onset

    Science.gov (United States)

    Wendling, Fabrice; Bartolomei, Fabrice; Bellanger, Jean-Jacques; Bourien, Jérôme; Chauvel, Patrick

    2003-01-01

    Low-voltage rapid discharges (or fast EEG ictal activity) constitute a characteristic electrophysiological pattern in focal seizures of human epilepsy. They are characterized by a decrease of signal voltage with a marked increase of signal frequency (typically beyond 25 Hz). They have long been observed in stereoelectroencephalographic (SEEG) signals recorded with intra-cerebral electrodes, generally occurring at seizure onset and simultaneously involving distinct brain regions. Spectral properties of rapid ictal discharges as well as spatial correlations measured between SEEG signals generated from distant sites before, during and after these discharges were studied. Cross-correlation estimates within typical EEG sub-bands and statistical tests performed in ten patients suffering from partial epilepsy (frontal, temporal or fronto-temporal) reveal that SEEG signals are significantly de-correlated during the discharge period compared to periods that precede and follow this discharge. These results can be interpreted as a functional decoupling of distant brain sites at seizure onset followed by an abnormally high re-coupling when the seizure develops. They lead to the concept of “disruption” that is complementary of that of “activation” (revealed by significantly high correlations between signals recorded during seizures), both giving insights into our understanding of pathophysiological processes involved in human partial epilepsies as well as in the interpretation of clinical semiology. PMID:12764064

  6. Peri-ictal signal changes in seven patients with status epilepticus: interesting MRI observations

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, Manoj K.; Sinha, Sanjib [National Institute of Mental Health and Neurosciences (NIMHANS), Department of Neurology, Bangalore, Karnataka (India); Ravishankar, Shivshankar; Shivshankar, Jai Jai [National Institute of Mental Health and Neurosciences (NIMHANS), Department of Neuroimaging and Interventional Radiology, Bangalore (India)

    2009-03-15

    Transient peri-ictal changes on imaging had been described following status epilepticus (SE), but its cause is not very well understood. We analyzed the magnetic resonance imaging (MRI) findings in SE patients in order to elucidate such changes including peri-ictal signal. This prospective study involved 34 patients (M/F 23:11, mean age 25.8 {+-} 17.2 years) who experienced SE. MRI was performed during or within 96 h of cessation of seizures. Twenty-five patients had generalized convulsive status epilectus (GCSE; ten secondary GCSE and 15 primary GCSE). Seven patients had epilepsia partialis continua and two patients non-convulsive SE. Eight patients had a history of seizures and three patients previous SE. The mean duration of SE prior to MRI was 89.2 {+-} 105.3 h (range 2-360 h). MRI provided diagnosis in 17 patients, and in 13 patients, no structural cause was identified. Peri-ictal focal signal changes with restricted diffusion on apparent diffusion coefficient maps were present in seven (20.6%) patients with SE (generalized convulsive, three; partial, three; non-convulsive, one). The changes were observed when MRI was performed during SE in 3/10 (30%) patients, or within 24 h in 1/7 (14.3%), 48 h in 1/5 (20%), 72 h in 1/6 (16.7%), or 96 h in 1/6 (16.7%) patients after cessation of seizures. Repeat MRI revealed disappearance of signal changes in two patients. Peri-ictal MR changes with restricted diffusion appear to be an effect rather than the cause of SE. (orig.)

  7. Epileptic network of hypothalamic hamartoma: An EEG-fMRI study.

    Science.gov (United States)

    Usami, Kiyohide; Matsumoto, Riki; Sawamoto, Nobukatsu; Murakami, Hiroatsu; Inouchi, Morito; Fumuro, Tomoyuki; Shimotake, Akihiro; Kato, Takeo; Mima, Tatsuya; Shirozu, Hiroshi; Masuda, Hiroshi; Fukuyama, Hidenao; Takahashi, Ryosuke; Kameyama, Shigeki; Ikeda, Akio

    2016-09-01

    To investigate the brain networks involved in epileptogenesis/encephalopathy associated with hypothalamic hamartoma (HH) by EEG with functional MRI (EEG-fMRI), and evaluate its efficacy in locating the HH interface in comparison with subtraction ictal SPECT coregistered to MRI (SISCOM). Eight HH patients underwent EEG-fMRI. All had gelastic seizures (GS) and 7 developed other seizure types. Using a general linear model, spike-related activation/deactivation was analyzed individually by applying a hemodynamic response function before, at, and after spike onset (time-shift model=-8-+4s). Group analysis was also performed. The sensitivity of EEG-fMRI in identifying the HH interface was compared with SISCOM in HH patients having unilateral hypothalamic attachment. EEG-fMRI revealed activation and/or deactivation in subcortical structures and neocortices in all patients. 6/8 patients showed activation in or around the hypothalamus with the HH interface with time-shift model before spike onset. Group analysis showed common activation in the ipsilateral hypothalamus, brainstem tegmentum, and contralateral cerebellum. Deactivation occurred in the default mode network (DMN) and bilateral hippocampi. Among 5 patients with unilateral hypothalamic attachment, activation in or around the ipsilateral hypothalamus was seen in 3 using EEG-fMRI, whereas hyperperfusion was seen in 1 by SISCOM. Group analysis of this preliminary study may suggest that the commonly activated subcortical network is related to generation of GS and that frequent spikes lead to deactivation of the DMN and hippocampi, and eventually to a form of epileptic encephalopathy. Inter-individual variance in neocortex activation explains various seizure types among patients. EEG-fMRI enhances sensitivity in detecting the HH interface compared with SISCOM. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Resected Brain Tissue, Seizure Onset Zone and Quantitative EEG Measures: Towards Prediction of Post-Surgical Seizure Control.

    Science.gov (United States)

    Rummel, Christian; Abela, Eugenio; Andrzejak, Ralph G; Hauf, Martinus; Pollo, Claudio; Müller, Markus; Weisstanner, Christian; Wiest, Roland; Schindler, Kaspar

    2015-01-01

    Epilepsy surgery is a potentially curative treatment option for pharmacoresistent patients. If non-invasive methods alone do not allow to delineate the epileptogenic brain areas the surgical candidates undergo long-term monitoring with intracranial EEG. Visual EEG analysis is then used to identify the seizure onset zone for targeted resection as a standard procedure. Despite of its great potential to assess the epileptogenicty of brain tissue, quantitative EEG analysis has not yet found its way into routine clinical practice. To demonstrate that quantitative EEG may yield clinically highly relevant information we retrospectively investigated how post-operative seizure control is associated with four selected EEG measures evaluated in the resected brain tissue and the seizure onset zone. Importantly, the exact spatial location of the intracranial electrodes was determined by coregistration of pre-operative MRI and post-implantation CT and coregistration with post-resection MRI was used to delineate the extent of tissue resection. Using data-driven thresholding, quantitative EEG results were separated into normally contributing and salient channels. In patients with favorable post-surgical seizure control a significantly larger fraction of salient channels in three of the four quantitative EEG measures was resected than in patients with unfavorable outcome in terms of seizure control (median over the whole peri-ictal recordings). The same statistics revealed no association with post-operative seizure control when EEG channels contributing to the seizure onset zone were studied. We conclude that quantitative EEG measures provide clinically relevant and objective markers of target tissue, which may be used to optimize epilepsy surgery. The finding that differentiation between favorable and unfavorable outcome was better for the fraction of salient values in the resected brain tissue than in the seizure onset zone is consistent with growing evidence that spatially

  9. EEG and Spelling Disabilities

    OpenAIRE

    J Gordon Millichap

    1991-01-01

    The EEGs in 23 13-year-old Finnish-speaking boys with spelling disabilities and in 21 matched controls were studied in the Departments of Child Neurology, Paediatrics, Clinical Neurophysiology and Psychology, University of Helsinki, Finland.

  10. EEG Controlled Wheelchair

    Directory of Open Access Journals (Sweden)

    Swee Sim Kok

    2016-01-01

    Full Text Available This paper describes the development of a brainwave controlled wheelchair. The main objective of this project is to construct a wheelchair which can be directly controlled by the brain without requires any physical feedback as controlling input from the user. The method employed in this project is the Brain-computer Interface (BCI, which enables direct communication between the brain and the electrical wheelchair. The best method for recording the brain’s activity is electroencephalogram (EEG. EEG signal is also known as brainwaves signal. The device that used for capturing the EEG signal is the Emotiv EPOC headset. This headset is able to transmit the EEG signal wirelessly via Bluetooth to the PC (personal computer. By using the PC software, the EEG signals are processed and converted into mental command. According to the mental command (e.g. forward, left... obtained, the output electrical signal is sent out to the electrical wheelchair to perform the desired movement. Thus, in this project, a computer software is developed for translating the EEG signal into mental commands and transmitting out the controlling signal wirelessly to the electrical wheelchair.

  11. Evaluation of dynamic scaling of growing interfaces in EEG fluctuations of seizures in animal model of temporal lobe epilepsy.

    Science.gov (United States)

    Martínez-González, Claudia Lizbeth; Balankin, Alexander; López, Tessy; Manjarrez-Marmolejo, Joaquín; Martínez-Ortiz, Efraín José

    2017-09-01

    Epileptic seizures, as a dynamic phenomenon in brain behavior, obey a scale-free behavior, frequently analyzed by electrical activity recording. This recording can be seen as a surface that roughens with time. Dynamic scaling studies roughening processes or growing interfaces. In this theory, a set of exponents -obtained from scale invariance properties- characterize rough interfaces growth. The aim of the present study was to investigate scaling behavior in EEG time series fluctuations of a chemical animal model of temporal lobe epilepsy, with dynamic scaling to detect changes on seizure onset. We analyzed local variables in different sampling intervals and estimated rough, scaling and dynamic exponents. Results exhibited long-range correlations in interictal activity. Results of renormalization and data collapsing confirmed that each epoch of EEG fluctuations for interictal, preictal and postictal collapse in a curve in different scales, each segment independently; remarkably, we found non-scaling behavior in seizures epochs. Data for the different sampling intervals for ictal period do not collapse in one curve, which implies that ictal activity does not exhibit the same scaling behavior than the other epochs. Statistical significant differences of growth exponent were found between interictal and ictal segment, while for scaling exponent, significant differences were found between interictal and postictal segment. These results confirm the potential of scaling exponents as characteristic parameters to detect changes on seizure onset, which suggests their use as inputs for analysis methods for seizure detection in long-term recordings, while changes in growth exponent are potentially useful for prediction purposes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Sleep disruption increases seizure susceptibility: Behavioral and EEG evaluation of an experimental model of sleep apnea.

    Science.gov (United States)

    Hrnčić, Dragan; Grubač, Željko; Rašić-Marković, Aleksandra; Šutulović, Nikola; Šušić, Veselinka; Bjekić-Macut, Jelica; Stanojlović, Olivera

    2016-03-01

    Sleep disruption accompanies sleep apnea as one of its major symptoms. Obstructive sleep apnea is particularly common in patients with refractory epilepsy, but causing factors underlying this are far from being resolved. Therefore, translational studies regarding this issue are important. Our aim was to investigate the effects of sleep disruption on seizure susceptibility of rats using experimental model of lindane-induced refractory seizures. Sleep disruption in male Wistar rats with implanted EEG electrodes was achieved by treadmill method (belt speed set on 0.02 m/s for working and 0.00 m/s for stop mode, respectively). Animals were assigned to experimental conditions lasting 6h: 1) sleep disruption (sleep interrupted, SI; 30s working and 90 s stop mode every 2 min; 180 cycles in total); 2) activity control (AC, 10 min working and 30 min stop mode, 9 cycles in total); 3) treadmill chamber control (TC, only stop mode). Afterwards, the animals were intraperitoneally treated with lindane (L, 4 mg/kg, SI+L, AC+L and TC+L groups) or dimethylsulfoxide (DMSO, SIc, ACc and TCc groups). Convulsive behavior was assessed by seizure incidence, latency time to first seizure, and its severity during 30 min after drug administration. Number and duration of ictal periods were determined in recorded EEGs. Incidence and severity of lindane-induced seizures were significantly increased, latency time significantly decreased in animals undergoing sleep disruption (SI+L group) compared with the animals from TC+L. Seizure latency was also significantly decreased in SI+L compared to AC+L groups. Number of ictal periods were increased and duration of it presented tendency to increase in SI+L comparing to AC+L. No convulsive signs were observed in TCc, ACc and SIc groups, as well as no ictal periods in EEG. These results indicate sleep disruption facilitates induction of epileptic activity in rodent model of lindane-epilepsy enabling translational research of this phenomenon. Copyright

  13. The EEG in psychiatry

    African Journals Online (AJOL)

    Adele

    2004-05-20

    May 20, 2004 ... chiatric disorders have a neurobiological basis. Nevertheless, the typically marked focal or generalised slowing found in the. EEG in patients with acute or chronic encephalopathies due to metabolic changes, infections, toxins, trauma and tumours is useful to the clinician in the differentiation of these disor-.

  14. On Quantitative Biomarkers of VNS Therapy Using EEG and ECG Signals.

    Science.gov (United States)

    Ravan, Maryam; Sabesan, Shivkumar; D'Cruz, O'Neill

    2017-02-01

    The goal of this work is to objectively evaluate the effectiveness of neuromodulation therapies, specifically, Vagus nerve stimulation (VNS) in reducing the severity of seizures in patients with medically refractory epilepsy. Using novel quantitative features obtained from combination of electroencephalographic (EEG) and electrocardiographic (ECG) signals around seizure events in 16 patients who underwent implantation of closed-loop VNS therapy system, namely AspireSR, we evaluated if automated delivery of VNS at the time of seizure onset reduces the severity of seizures by reducing EEG spatial synchronization as well as the duration and magnitude of heart rate increase. Unsupervised classification was subsequently applied to test the discriminative ability and validity of these features to measure responsiveness to VNS therapy. Results of application of this methodology to compare 105 pre-VNS treatment and 107 post-VNS treatment seizures revealed that seizures that were acutely stimulated using VNS had a reduced ictal spread as well as reduced impact on cardiovascular function compared to the ones that occurred prior to any treatment. Furthermore, application of an unsupervised fuzzy-c-mean classifier to evaluate the ability of the combined EEG-ECG based features to classify pre and post-treatment seizures achieved a classification accuracy of 85.85%. These results indicate the importance of timely delivery of VNS to reduce seizure severity and thus help achieve better seizure control for patients with epilepsy. The proposed set of quantitative features could be used as potential biomarkers for predicting long-term response to VNS therapy.

  15. NREM Arousal Parasomnias and Their Distinction from Nocturnal Frontal Lobe Epilepsy: A Video EEG Analysis

    Science.gov (United States)

    Derry, Christopher P.; Harvey, A. Simon; Walker, Matthew C.; Duncan, John S.; Berkovic, Samuel F.

    2009-01-01

    Study Objectives. To describe the semiological features of NREM arousal parasomnias in detail and identify features that can be used to reliably distinguish parasomnias from nocturnal frontal lobe epilepsy (NFLE). Design. Systematic semiologial evaluation of parasomnias and NFLE seizures recorded on video-EEG monitoring. Patients. 120 events (57 parasomnias, 63 NFLE seizures) from 44 subjects (14 males). Interventions. The presence or absence of 68 elemental clinical features was determined in parasomnias and NFLE seizures. Qualitative analysis of behavior patterns and ictal EEG was undertaken. Statistical analysis was undertaken using established techniques. Results. Elemental clinical features strongly favoring parasomnias included: interactive behavior, failure to wake after event, and indistinct offset (all P night terrors as prototypical behavior patterns of NREM parasomnias, but as a hierarchical continuum rather than distinct entities. Our observations provide an evidence base to assist in the clinical diagnosis of NREM parasomnias, and their distinction from NFLE seizures, on semiological grounds. Citation: Derry CP; Harvey AS; Walker MC; Duncan JS; Berkovic SF. NREM arousal parasomnias and their distinction from nocturnal frontal lobe epilepsy: a video EEG analysis. SLEEP 2009;32(12):1637-1644. PMID:20041600

  16. Does sleep deprivation alter functional EEG networks in children with focal epilepsy?

    Directory of Open Access Journals (Sweden)

    Eric evan Diessen

    2014-04-01

    Full Text Available Electroencephalography (EEG recordings after sleep deprivation increase the diagnostic yield in patients suspected of epilepsy if the routine EEG remains inconclusive. Sleep deprivation is associated with increased interictal EEG abnormalities in patients with epilepsy, but the exact mechanism is unknown. In this feasibility study, we used a network analytical approach to provide novel insights into this clinical observation. The aim was to characterize the effect of sleep deprivation on interictal functional network organization using a unique dataset of paired routine and sleep deprivation recordings in patients and controls. We included twenty-one children referred to the first seizure clinic of our center with suspected new onset focal epilepsy in whom a routine interictal and a sleep deprivation EEG (SD-EEG were performed. Seventeen children, in whom the diagnosis of epilepsy was excluded, served as controls. For both time points weighted functional networks were constructed based on interictal artifact free time-series. Routine and sleep deprivation networks were characterized at different frequency bands using minimum spanning tree (MST measures (leaf number and diameter and classical measures of integration (path length and segregation (clustering coefficient. A significant interaction was found for leaf number and diameter between patients and controls after sleep deprivation: patients showed a shift towards a more path-like MST network whereas controls showed a shift towards a more star-like MST network. This shift in network organization after sleep deprivation in patients is in accordance with previous studies showing a more regular network organization in the ictal state and might relate to the increased epileptiform abnormalities found in patients after sleep deprivation. Larger studies are needed to verify these results. Finally, MST measures were more sensitive in detecting network changes as compared to the classical measures of

  17. EEG analyses with SOBI.

    Energy Technology Data Exchange (ETDEWEB)

    Glickman, Matthew R.; Tang, Akaysha (University of New Mexico, Albuquerque, NM)

    2009-02-01

    The motivating vision behind Sandia's MENTOR/PAL LDRD project has been that of systems which use real-time psychophysiological data to support and enhance human performance, both individually and of groups. Relevant and significant psychophysiological data being a necessary prerequisite to such systems, this LDRD has focused on identifying and refining such signals. The project has focused in particular on EEG (electroencephalogram) data as a promising candidate signal because it (potentially) provides a broad window on brain activity with relatively low cost and logistical constraints. We report here on two analyses performed on EEG data collected in this project using the SOBI (Second Order Blind Identification) algorithm to identify two independent sources of brain activity: one in the frontal lobe and one in the occipital. The first study looks at directional influences between the two components, while the second study looks at inferring gender based upon the frontal component.

  18. Ictal ECG changes in temporal lobe epilepsy Alterações eletrocardiográficas ictais em epilepsia do lobo temporal

    Directory of Open Access Journals (Sweden)

    L.M. Li

    1995-09-01

    Full Text Available Changes in cardiac rhythm may occur during epileptic seizures and this has been suggested as a possible mechanism for sudden unexpected death amongst patients with chronic epilepsy (SUDEP. We have studied ECG changes during 61 complex partial seizures of temporal lobe origin in 20 patients. Tachycardia was observed in 24/61 (39% and bradycardia in 3/61 (5%. The mean and median tachycardia rate was 139 and 140 beats/min (range 120-180. The longest R-R interval observed was 9 seconds. No difference was found in regard to the lateralisation of seizures and cardiac arrhytmia. One of the patients with bradycardia was fitted with a demand cardiac pacemaker, which appeared to decrease the number of his falls. In conclusion, ictal cardiac changes which may be seen in temporal lobe epilepsy (TLE are sinus tachycardia and occasionally sinus bradycardia. Patients presenting vague complains suggestive of either TLE or cardiac dysrhythmia, simultaneous monitoring with EEG/ECG is required, and if the episodes are frequent, video-EEG should be considered. Further studies on this subject are warranted as this may shed some light on possible mechanisms for SUDEP.Alterações no ritmo cardíaco podem ocorrer durante crises epilépticas. Estas alterações têm sido sugeridas como possível mecanismo para explicar morte súbita em pacientes com epilepsia crônica. Analisamos o eltrocardiograma (ECG em 61 crises parciais complexas do lobo temporal de 20 pacientes. Taquicardia foi observada em 24/61 (39% e bradicardia em 3/61 (5%. A média e a mediana da taquicardia foram 139 e 140 batimentos por minuto (variando de 120-180. O intervalo R-R mais longo foi 9 segundos. Não houve diferença em relação a lateralisação das crises e alteração do ritmo cardíaco. Um paciente com bradicardia recebeu marcapasso de demanda, com diminuição importante das suas quedas durante as crises. Em conclusão, as alterações cardíacas ictais em crises do lobo temporal mais

  19. Dual protective effect of Passiflora incarnata in epilepsy and associated post-ictal depression.

    Science.gov (United States)

    Singh, Bhupinder; Singh, Damanpreet; Goel, Rajesh Kumar

    2012-01-06

    Passiflora incarnata L. (Passifloraceae) has been used for the treatment of epilepsy in several traditional systems of medicine. The aerial parts of Passiflora incarnata contain multiple bioactive metabolites such as, flavonoids (like, chrysin that show CNS depressant activity by agonizing GABA-benzodiazepine receptor), amino acids (like, GABA), harmala alkaloids (reversible monoamine oxidase-A inhibitor), etc. In view of this, the present study was designed to investigate dual protective effect of the hydroethanolic extract of Passiflora incarnata in pentylenetetrazol (PTZ)-induced seizure and associated post-ictal depression. Different groups of mice were administered with repeated subconvulsive doses of PTZ (50mg/kg; i.p.) at an interval of 5 days for 15 days. From 5th to 15th day the animals in different groups were administered daily with varying doses of hydroethanolic extract of Passiflora incarnata (150, 300, and 600mg/kg; i.p.), diazepam (2mg/kg; i.p.) and vehicle. On every 5th day, after PTZ treatment, seizure severity (score) was noted. Following convulsive episodes the locomotor activity (using actophotometer) and immobility period (using forced swim test) were also determined. On 15th day after behavioral assessment, the brain serotonin and noradrenaline levels were determined using spectrofluorometric methods. Treatment with the extract significantly (p<0.05) reduced the seizure severity and immobility period as compared to vehicle control, in a dose and time-dependent manner. Moreover, the extract treatment retained the serotonin and noradrenaline levels of the brain. The results of present study concluded that the hydroethanolic extract of Passiflora incarnata suppress PTZ-induced seizures, and ameliorates its associated post-ictal depression, which has been found to be get worsened with the standard antiepileptic drug, diazepam. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  20. Gap Junctions Contribute to Ictal/Interictal Genesis in Human Hypothalamic Hamartomas

    Directory of Open Access Journals (Sweden)

    Jie Wu

    2016-06-01

    Full Text Available Human hypothalamic hamartoma (HH is a rare subcortical lesion associated with treatment-resistant epilepsy. Cellular mechanisms responsible for epileptogenesis are unknown. We hypothesized that neuronal gap junctions contribute to epileptogenesis through synchronous activity within the neuron networks in HH tissue. We studied surgically resected HH tissue with Western-blot analysis, immunohistochemistry, electron microscopy, biocytin microinjection of recorded HH neurons, and microelectrode patch clamp recordings with and without pharmacological blockade of gap junctions. Normal human hypothalamus tissue was used as a control. Western blots showed increased expression of both connexin-36 (Cx36 and connexin-43 (Cx43 in HH tissue compared with normal human mammillary body tissue. Immunohistochemistry demonstrated that Cx36 and Cx43 are expressed in HH tissue, but Cx36 was mainly expressed within neuron clusters while Cx43 was mainly expressed outside of neuron clusters. Gap-junction profiles were observed between small HH neurons with electron microscopy. Biocytin injection into single recorded small HH neurons showed labeling of adjacent neurons, which was not observed in the presence of a neuronal gap-junction blocker, mefloquine. Microelectrode field recordings from freshly resected HH slices demonstrated spontaneous ictal/interictal-like discharges in most slices. Bath-application of gap-junction blockers significantly reduced ictal/interictal-like discharges in a concentration-dependent manner, while not affecting the action-potential firing of small gamma-aminobutyric acid (GABA neurons observed with whole-cell patch-clamp recordings from the same patient's HH tissue. These results suggest that neuronal gap junctions between small GABAergic HH neurons participate in the genesis of epileptic-like discharges. Blockade of gap junctions may be a new therapeutic strategy for controlling seizure activity in HH patients.

  1. Ictal heart rate changes and the effects of vagus nerve stimulation for patients with refractory epilepsy

    Directory of Open Access Journals (Sweden)

    Chen W

    2017-09-01

    Full Text Available Wei Chen,1 Fan-Gang Meng2,3 1Department of Neurology, Liaocheng People’s Hospital, Liaocheng, 2Beijing Neurosurgical Institute, Capital Medical University, 3Beijing Key Laboratory of Neuromodulation, Beijing Municipal Science and Technology Commission, Beijing, People’s Republic of China Abstract: Vagus nerve stimulation (VNS shows long-term efficiency worldwide in most pharmacoresistant patients with epilepsy; however, there are still a small number of patients who are non-responders to VNS therapy. It has been shown that VNS treatment outcomes for drug-resistant epilepsy may be predicted by preoperative heart-rate variability measurements and that patients with epilepsy with ictal tachycardia (IT during seizures have good responses to VNS. However, few studies have reported the efficacy of VNS in patients with epilepsy with ictal bradycardia (IB or normal heart rate (HR, and none have explored the possible mechanisms of VNS efficacy based on different HR types. HR during seizures varies, and we presume that different HRs during seizures may impact the effects of VNS. It has been shown that blood pressure in the human body needs to be maintained through the arterial baroreflex (ABR. VNS efficacy in patients with epilepsy with IT, IB, and normal HR during seizures may be related to ABR. Mechanical signals generated by VNS are similar to the autonomic nerve pathways and, thus, we propose the hypothesis that different HRs during seizures can predict VNS efficacy in patients. If VNS is highly efficient in patients with IT during seizures, VNS in patients with a normal HR during seizures may be less efficient, and may even be inefficient in patients with IB during seizures. Keywords: heart rate changes, VNS efficacy, refractory epilepsy 

  2. Comparison of Amplitude-Integrated EEG and Conventional EEG in a Cohort of Premature Infants.

    Science.gov (United States)

    Meledin, Irina; Abu Tailakh, Muhammad; Gilat, Shlomo; Yogev, Hagai; Golan, Agneta; Novack, Victor; Shany, Eilon

    2017-03-01

    To compare amplitude-integrated EEG (aEEG) and conventional EEG (EEG) activity in premature neonates. Biweekly aEEG and EEG were simultaneously recorded in a cohort of infants born less than 34 weeks gestation. aEEG recordings were visually assessed for lower and upper border amplitude and bandwidth. EEG recordings were compressed for visual evaluation of continuity and assessed using a signal processing software for interburst intervals (IBI) and frequencies' amplitude. Ten-minute segments of aEEG and EEG indices were compared using regression analysis. A total of 189 recordings from 67 infants were made, from which 1697 aEEG/EEG pairs of 10-minute segments were assessed. Good concordance was found for visual assessment of continuity between the 2 methods. EEG IBI, alpha and theta frequencies' amplitudes were negatively correlated to the aEEG lower border while conceptional age (CA) was positively correlated to aEEG lower border ( P continuity and amplitude.

  3. Assessment of a scalp EEG-based automated seizure detection system.

    Science.gov (United States)

    Kelly, K M; Shiau, D S; Kern, R T; Chien, J H; Yang, M C K; Yandora, K A; Valeriano, J P; Halford, J J; Sackellares, J C

    2010-11-01

    The purpose of this study was to evaluate and validate an offline, automated scalp EEG-based seizure detection system and to compare its performance to commercially available seizure detection software. The test seizure detection system, IdentEvent™, was developed to enhance the efficiency of post-hoc long-term EEG review in epilepsy monitoring units. It translates multi-channel scalp EEG signals into multiple EEG descriptors and recognizes ictal EEG patterns. Detection criteria and thresholds were optimized in 47 long-term scalp EEG recordings selected for training (47 subjects, ∼3653h with 141 seizures). The detection performance of IdentEvent was evaluated using a separate test dataset consisting of 436 EEG segments obtained from 55 subjects (∼1200h with 146 seizures). Each of the test EEG segments was reviewed by three independent epileptologists and the presence or absence of seizures in each epoch was determined by majority rule. Seizure detection sensitivity and false detection rate were calculated for IdentEvent as well as for the comparable detection software (Persyst's Reveal®, version 2008.03.13, with three parameter settings). Bootstrap re-sampling was applied to establish the 95% confidence intervals of the estimates and for the performance comparison between two detection algorithms. The overall detection sensitivity of IdentEvent was 79.5% with a false detection rate (FDR) of 2 per 24h, whereas the comparison system had 80.8%, 76%, and 74% sensitivity using its three detection thresholds (perception score) with FDRs of 13, 8, and 6 per 24h, respectively. Bootstrap 95% confidence intervals of the performance difference revealed that the two detection systems had comparable detection sensitivity, but IdentEvent generated a significantly (p<0.05) smaller FDR. The study validates the performance of the IdentEvent™ seizure detection system. With comparable detection sensitivity, an improved false detection rate makes the automated seizure

  4. Panayiotopoulos syndrome: a clinical, EEG, and neuropsychological study of 93 consecutive patients.

    Science.gov (United States)

    Specchio, Nicola; Trivisano, Marina; Di Ciommo, Vincenzo; Cappelletti, Simona; Masciarelli, Giovanni; Volkov, Josiv; Fusco, Lucia; Vigevano, Federico

    2010-10-01

    To explore the clinical, electroencephalography (EEG), neuropsychological features, and prognosis of Panayiotopoulos syndrome (PS). Of 1,794 children aged between 1 and 14 years referred for the first afebrile focal seizure, between January 1992 and December 2004, 93 (5.2%) had PS according to clinical criteria. Age at onset ranged from 1.1 to 8.6 years, and was earlier in children with more than one seizure. Autonomic seizures followed a stereotypical onset and progression. Emesis, pallor, or flushing was almost always among the first symptoms that usually culminated in vomiting (77.4% of patients). More than half (55%) of seizures were longer than 30 min but these did not appear to affect remission and number of seizures. Interictal EEG showed great variability, with 79.5% of patients showing spikes of variable localizations and evolution over time; 16.1% had background abnormalities only, and 5.4% had consistently normal EEG studies. Onsets in five ictal EEGs were posterior or anterior-left or right. On neuropsychological testing, IQ and subtests of Wechsler Intelligence Scale for Children-Revised (WISC-R) were within normal limits, although some minor statistically significant differences were found in arithmetic, comprehension, and picture arrangement in comparison with controls. Cumulative probability of recurrence was 57.6%, 45.6%, 35.1%, and 11.7% at 6, 12, 24, and 36 months, respectively, after the first seizure. Thirty-four (58.6%) of 59 patients treated with antiepileptic drugs continued having seizures before ultimate remission. PS is a uniform childhood susceptibility to autonomic seizures that is related to early age of development and with excellent prognosis with regard to seizure remission and neuropsychological development. Wiley Periodicals, Inc. © 2010 International League Against Epilepsy.

  5. Dry EEG Electrodes

    Directory of Open Access Journals (Sweden)

    M. A. Lopez-Gordo

    2014-07-01

    Full Text Available Electroencephalography (EEG emerged in the second decade of the 20th century as a technique for recording the neurophysiological response. Since then, there has been little variation in the physical principles that sustain the signal acquisition probes, otherwise called electrodes. Currently, new advances in technology have brought new unexpected fields of applications apart from the clinical, for which new aspects such as usability and gel-free operation are first order priorities. Thanks to new advances in materials and integrated electronic systems technologies, a new generation of dry electrodes has been developed to fulfill the need. In this manuscript, we review current approaches to develop dry EEG electrodes for clinical and other applications, including information about measurement methods and evaluation reports. We conclude that, although a broad and non-homogeneous diversity of approaches has been evaluated without a consensus in procedures and methodology, their performances are not far from those obtained with wet electrodes, which are considered the gold standard, thus enabling the former to be a useful tool in a variety of novel applications.

  6. INTELLIGENT EEG ANALYSIS

    Directory of Open Access Journals (Sweden)

    M. Murugesan

    2011-04-01

    Full Text Available Brain is the wonderful organ of human body. It is the agent of information collection and transformation. The neural activity of the human brain starts between the 17th and 23rd week of prenatal development. It is believed that from this early stage and throughout life electrical signals are generated by the brain function but also the status of the whole body. Understanding of neuronal functions and neurophysiologic properties of the brain function together with the mechanisms underlying the generation of signals and their recording is, however, vital for those who deal with these signals for detection, diagnosis, and treatment of brain disorders and the related diseases. This research paper concentrated only on brain tumor detection. Using minimum electrode location the brain tumor possibility is detected. This paper is separated into two parts: the First part deals with electrode location on the scalp and the second part deals with how the fuzzy logic rule based algorithm is applied for estimation of brain tumor from EEG. Basically 8 locations are identified. After acquiring the pure EEG signal Fuzzy Logic Rule is applied to predict the possibility of brain tumor.

  7. Ictal SPECT in patients with rapid eye movement sleep behaviour disorder.

    Science.gov (United States)

    Mayer, Geert; Bitterlich, Marion; Kuwert, Torsten; Ritt, Philipp; Stefan, Hermann

    2015-05-01

    Rapid eye movement sleep behaviour disorder is a rapid eye movement parasomnia clinically characterized by acting out dreams due to disinhibition of muscle tone in rapid eye movement sleep. Up to 80-90% of the patients with rapid eye movement sleep behaviour disorder develop neurodegenerative disorders within 10-15 years after symptom onset. The disorder is reported in 45-60% of all narcoleptic patients. Whether rapid eye movement sleep behaviour disorder is also a predictor for neurodegeneration in narcolepsy is not known. Although the pathophysiology causing the disinhibition of muscle tone in rapid eye movement sleep behaviour disorder has been studied extensively in animals, little is known about the mechanisms in humans. Most of the human data are from imaging or post-mortem studies. Recent studies show altered functional connectivity between substantia nigra and striatum in patients with rapid eye movement sleep behaviour disorder. We were interested to study which regions are activated in rapid eye movement sleep behaviour disorder during actual episodes by performing ictal single photon emission tomography. We studied one patient with idiopathic rapid eye movement sleep behaviour disorder, one with Parkinson's disease and rapid eye movement sleep behaviour disorder, and two patients with narcolepsy and rapid eye movement sleep behaviour disorder. All patients underwent extended video polysomnography. The tracer was injected after at least 10 s of consecutive rapid eye movement sleep and 10 s of disinhibited muscle tone accompanied by movements registered by an experienced sleep technician. Ictal single photon emission tomography displayed the same activation in the bilateral premotor areas, the interhemispheric cleft, the periaqueductal area, the dorsal and ventral pons and the anterior lobe of the cerebellum in all patients. Our study shows that in patients with Parkinson's disease and rapid eye movement sleep behaviour disorder-in contrast to wakefulness

  8. Musicogenic epilepsy: review of the literature and case report with ictal single photon emission computed tomography.

    Science.gov (United States)

    Wieser, H G; Hungerbühler, H; Siegel, A M; Buck, A

    1997-02-01

    We report a case of musicogenic epilepsy with ictal single photon emission computed tomography (SPECT) study and discuss the findings of this patient in the context of 76 cases with musicogenic epilepsy described in the literature and seven other cases followed in Zurich. We analyzed the 83 patients according to the precipitating musical factors, type of epilepsy, presumed localization of seizure onset, and demographic data. Fourteen of 83 patients (17%) had seizures triggered exclusively by music. At time of examination, music was the only known precipitating stimulus in 65 of 83 patients (78%). Various characteristics of the musical stimulus were significant, e.g., musical category, familiarity, and instruments. Musicogenic epilepsy is a particular form of epilepsy with a strong correlation to the temporal lobe and a right-sided preponderance. A high musial standard might predispose for musicogenic epilepsy. Moreover, the majority of cases do not fall into the category of a strictly defined "reflex epilepsy," but appear to depend on the indermediary of a certain emotional reaction mediated through limbic mesial temporal lobe structures.

  9. A fuzzy rule-based system for epileptic seizure detection in intracranial EEG.

    Science.gov (United States)

    Aarabi, A; Fazel-Rezai, R; Aghakhani, Y

    2009-09-01

    We present a method for automatic detection of seizures in intracranial EEG recordings from patients suffering from medically intractable focal epilepsy. We designed a fuzzy rule-based seizure detection system based on knowledge obtained from experts' reasoning. Temporal, spectral, and complexity features were extracted from IEEG segments, and spatio-temporally integrated using the fuzzy rule-based system for seizure detection. A total of 302.7h of intracranial EEG recordings from 21 patients having 78 seizures was used for evaluation of the system. The system yielded a sensitivity of 98.7%, a false detection rate of 0.27/h, and an average detection latency of 11s. There was only one missed seizure. Most of false detections were caused by high-amplitude rhythmic activities. The results from the system correlate well with those from expert visual analysis. The fuzzy rule-based seizure detection system enabled us to deal with imprecise boundaries between interictal and ictal IEEG patterns. This system may serve as a good seizure detection tool with high sensitivity and low false detection rate for monitoring long-term IEEG.

  10. Ictal 99mTc-ECD brain SPECT imaging: localization of seizure foci and correlation with semiology in temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Kang, Do Young; Ryu, Jin Sook; Lee, Hee Kyung; Ma, Hyeo Il; Lee, Sang Ahm; Lee, Jung Kyo; Kang, Joong Koo

    1997-01-01

    The purpose of this study was to evaluate the usefulness of ictal 99m Tc-ECD brain SPECT in temporal lobe epilepsy (TLE) patients for presurgical localization of seizure foci, and to correlate ictal SPECT patterns with the semiology of seizure. ictal 99m Tc-ECD Brain SPECT was performed in 23 TLE patients whose MRI showed unilateral hippocampal atrophy (18 patients), other focal temporal lesions (4 patients) and normal finding (1 patient). Under CCTV monitoring, injection was done during ictal period in all patients with the mean delay of 38.5±17.3 sec (mean seizure duration : 90.5±35.9 sec). Ictal 99m Tc-ECD Brain SPECT was visually analysed by three blinded observers. All patients underwent temporal lobectomy with a minimum 3 months follow-up (range 3-29 months) ; all had good post-surgical seizure control (Engel's calssification class I). Ictal 99m Tc-ECD Brain SPECT showed unilateral temporal hyperperfusion concordant with epileptic foci in 22/23 (95.7%), whereas non-lateralization in 1/23 (4.3%). The hyperperfusion of the ipsilateral basal ganglia was present in 72.7% (16/22) of patients with dystonic/tonic posture of the contralateral hand. The contralateral cerebellar hyperperfusion was observed in the 7/22 (32%). The group with secondary generalized tonic clonic seizure (GTC) had brain stem and bilateral thalamic hyperperfusion in 4/7 (57.1%) while the group without secondary GTC had the same hyperperfusion in 1/16 (6.3%). There was statistically significant difference in brain stem and bilateral thalamic perfusion between two groups. Ictal 99m Tc-ECD Brain SPECT is a useful modality in pre-surgical localization of the epileptic foci and well correlated with the semiology of seizure

  11. Ictal {sup 99m}Tc-ECD brain SPECT imaging: localization of seizure foci and correlation with semiology in temporal lobe epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Do Young; Ryu, Jin Sook; Lee, Hee Kyung; Ma, Hyeo Il; Lee, Sang Ahm; Lee, Jung Kyo; Kang, Joong Koo [Asan Medical Center, Seoul (Korea, Republic of)

    1997-07-01

    The purpose of this study was to evaluate the usefulness of ictal {sup 99m}Tc-ECD brain SPECT in temporal lobe epilepsy (TLE) patients for presurgical localization of seizure foci, and to correlate ictal SPECT patterns with the semiology of seizure. ictal {sup 99m}Tc-ECD Brain SPECT was performed in 23 TLE patients whose MRI showed unilateral hippocampal atrophy (18 patients), other focal temporal lesions (4 patients) and normal finding (1 patient). Under CCTV monitoring, injection was done during ictal period in all patients with the mean delay of 38.5{+-}17.3 sec (mean seizure duration : 90.5{+-}35.9 sec). Ictal {sup 99m}Tc-ECD Brain SPECT was visually analysed by three blinded observers. All patients underwent temporal lobectomy with a minimum 3 months follow-up (range 3-29 months) ; all had good post-surgical seizure control (Engel's calssification class I). Ictal {sup 99m}Tc-ECD Brain SPECT showed unilateral temporal hyperperfusion concordant with epileptic foci in 22/23 (95.7%), whereas non-lateralization in 1/23 (4.3%). The hyperperfusion of the ipsilateral basal ganglia was present in 72.7% (16/22) of patients with dystonic/tonic posture of the contralateral hand. The contralateral cerebellar hyperperfusion was observed in the 7/22 (32%). The group with secondary generalized tonic clonic seizure (GTC) had brain stem and bilateral thalamic hyperperfusion in 4/7 (57.1%) while the group without secondary GTC had the same hyperperfusion in 1/16 (6.3%). There was statistically significant difference in brain stem and bilateral thalamic perfusion between two groups. Ictal {sup 99m}Tc-ECD Brain SPECT is a useful modality in pre-surgical localization of the epileptic foci and well correlated with the semiology of seizure.

  12. Electroencephalogram (EEG) duration needed to detect abnormalities in angelman syndrome: is 1 hour of overnight recording sufficient?

    Science.gov (United States)

    Robinson, Althea A; Goldman, Suzanne; Barnes, Gregory; Goodpaster, Luke; Malow, Beth A

    2015-01-01

    Approximately, 90% of patients with Angelman syndrome present with epileptic seizures. Obtaining an electroencephalogram (EEG) with sleep improves the chances of detecting ictal, interictal, and benign abnormal rhythms in Angelman syndrome. However, electroencephalograms, even when obtained during sleep, can be challenging in this population because of tactile sensitivities as well as anxiety related to a novel environment. We tested the hypothesis that 1 hour of sleep on an electroencephalogram would provide as much information as an entire night of electroencephalogram recording, yet more than a routine electroencephalogram conducted during the day. Overnight polysomnograms were collected in 14 children with Angelman syndrome seen at Vanderbilt University. All patients who obtained sleep within the first hour of the overnight electroencephalogram had interictal discharges recorded. Our results show that when sleep is obtained, a 1-hour electroencephalogram yields just as much information as recording an entire night. © The Author(s) 2014.

  13. Clinical characterization of the pre-ictal state in the pediatric population: A caretaker's perspective.

    Science.gov (United States)

    Patel, Puja; Ferastraoaru, Victor; Gold, Dov; Lipnick, Andrew; Jehle, Rana; Haut, Sheryl R

    2017-05-01

    The unpredictability of seizures causes distress to patients with epilepsy and their caretakers. To date, no studies have explored seizure prediction specifically in the pediatric population. If the period of time preceding a seizure can be reliably identified, either by child or caretaker, there may be a role for pre-emptive interventions. The aim of this study was to investigate caretaker seizure prediction. A questionnaire was distributed to caretakers of patients with epilepsy. The patients were 0-21years old and experienced ≥1 seizure within the past year. We excluded patients with non-epileptic seizures or daily seizures. One hundred and fifty of 240 questionnaires met criteria. Of these, 32 (21.6%) caretakers indicated a positive report of seizure prediction. Age of seizure onset was earlier in the positive predictive group (3.3±3.3years) than in the non-predictor group (5.3±4.8years) (p=0.01). The most common pre-ictal symptoms reported were being tired, hazy look, and sleepiness. A total of 76.6% of caretakers reported at least one seizure precipitant. The prevalence of positive caretaker seizure prediction in this study is similar to that of seizure self-prediction in adult studies. These findings will be used to design prospective online or electronic diary studies to further investigate the caretaker's, as well as children's, perspectives on seizure prediction. We anticipate that this investigation may lead to novel treatments during times of high seizure risk. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Electrical Stimulations of the Human Insula: Their Contribution to the Ictal Semiology of Insular Seizures.

    Science.gov (United States)

    Mazzola, Laure; Mauguière, François; Isnard, Jean

    2017-07-01

    Stereotactic stimulations of the insular cortex through intracranial electrodes aim at characterizing the semiology of insular seizures. These stimulations, carried out in the context of Stereo-Electro-Encephalography (SEEG) during presurgical monitoring of epilepsy, reproduce the ictal symptoms observed during the development of insular seizures. The authors reviewed the results of insular stimulations performed in 222 patients admitted between 1997 and 2015 for presurgical SEEG exploration of atypical temporal or perisylvian epilepsy. Stimulations (50 Hz, trains of 5 seconds, pulses of 0.5 ms, intensity 0.2-3.5 mA) were carried out using transopercular electrodes implanted orthogonal to midsagittal plane. Out of a total of 669 stimulations, 550 were clinically eloquent in the absence of any postdischarge (237 and 313, respectively, in the right and left insulae). Somatosensory responses (61% of evoked sensations) including pain and visceral sensations (14.9%) were the most frequent, followed by auditory sensations (8%), vestibular illusions (7.5%), speech impairment (5%), gustatory, (2.7%), and olfactory (1%) sensations. Although these responses showed some functional segregation (in particular a privileged pain representation in the postero-superior quadrant), there was a clear spatial overlap between representations of the different modalities. Symptoms evoked by insular stimulations are multiple. None of them can be considered as absolutely specific to the insular cortex, but the occurrence in given seizure of a somatosensory symptom such as pain or of a laryngeal spasm associated with vestibular, auditory, aphasic, or olfacto-gustatory symptoms points to a discharge development in the insular cortex, which is the only cortical region where stimulations demonstrate such a multimodal representation.

  15. EEG frequency PCA in EEG-ERP dynamics.

    Science.gov (United States)

    Barry, Robert J; De Blasio, Frances M

    2018-05-01

    Principal components analysis (PCA) has long been used to decompose the ERP into components, and these mathematical entities are increasingly accepted as meaningful and useful representatives of the electrophysiological components constituting the ERP. A similar expansion appears to be beginning in regard to decomposition of the EEG amplitude spectrum into frequency components via frequency PCA. However, to date, there has been no exploration of the brain's dynamic EEG-ERP linkages using PCA decomposition to assess components in each measure. Here, we recorded intrinsic EEG in both eyes-closed and eyes-open resting conditions, followed by an equiprobable go/no-go task. Frequency PCA of the EEG, including the nontask resting and within-task prestimulus periods, found seven frequency components within the delta to beta range. These differentially predicted PCA-derived go and no-go N1 and P3 ERP components. This demonstration suggests that it may be beneficial in future brain dynamics studies to implement PCA for the derivation of data-driven components from both the ERP and EEG. © 2017 Society for Psychophysiological Research.

  16. The effective connectivity of the seizure onset zone and ictal perfusion changes in amygdala kindled rhesus monkeys.

    Science.gov (United States)

    Cleeren, Evy; Premereur, Elsie; Casteels, Cindy; Goffin, Karolien; Janssen, Peter; Van Paesschen, Wim

    2016-01-01

    Epileptic seizures are network-level phenomena. Hence, epilepsy may be regarded as a circuit-level disorder that cannot be understood outside this context. Better insight into the effective connectivity of the seizure onset zone and the manner in which seizure activity spreads could lead to specifically-tailored therapies for epilepsy. We applied the electrical amygdala kindling model in two rhesus monkeys until these animals displayed consistent stage IV seizures. At this stage, we investigated the effective connectivity of the amygdala by means of electrical microstimulation during fMRI (EM-fMRI). In addition, we imaged changes in perfusion during a seizure using ictal SPECT perfusion imaging. The spatial overlap between the connectivity network and the ictal perfusion network was assessed both at the regional level, by calculating Dice coefficients using anatomically defined regions of interest, and at the voxel level. The kindled amygdala was extensively connected to bilateral cortical and subcortical structures, which in many cases were connected multisynaptically to the amygdala. At the regional level, the spatial extents of many of these fMRI activations and deactivations corresponded to the respective increases and decreases in perfusion imaged during a stage IV seizure. At the voxel level, however, some regions showed residual seizure-specific activity (not overlapping with the EM-fMRI activations) or fMRI-specific activation (not overlapping with the ictal SPECT activations), indicating that frequently, only a part of a region anatomically connected to the seizure onset zone participated in seizure propagation. Thus, EM-fMRI in the amygdala of electrically-kindled monkeys reveals widespread areas that are often connected multisynaptically to the seizure focus. Seizure activity appears to spread, to a large extent, via these connected areas.

  17. Statistical voxel-wise analysis of ictal SPECT reveals pattern of abnormal perfusion in patients with temporal lobe epilepsy Análise estatística baseada em voxel do SPECT ictal revela um padrão de alteração perfusional em pacientes com epilepsia de lobo temporal

    Directory of Open Access Journals (Sweden)

    Bárbara Juarez Amorim

    2005-12-01

    Full Text Available OBJECTIVE: To investigate the pattern of perfusion abnormalities in ictal and interictal brain perfusion SPECT images (BSI from patients with temporal lobe epilepsy (TLE. METHOD: It was acquired interictal and ictal BSI from 24 patients with refractory TLE. BSIs were analyzed by visual inspection and statistical parametric mapping (SPM2. Statistical analysis compared the patients group to a control group of 50 volunteers. The images from patients with left-TLE were left-right flipped. RESULTS: It was not observed significant perfusional differences in interictal scans with SPM. Ictal BSI in SPM analysis revealed hyperperfusion within ipsilateral temporal lobe (epileptogenic focus and also contralateral parieto-occipital region, ipsilateral posterior cingulate gyrus, occipital lobes and ipsilateral basal ganglia. Ictal BSI also showed areas of hypoperfusion. CONCLUSION: In a group analysis of ictal BSI of patients with TLE, voxel-wise analysis detects a network of distant regions of perfusional alteration which may play active role in seizure genesis and propagation.OBJETIVO: Investigar o padrão de anormalidades perfusionais no SPECT de perfusão cerebral (SPC ictal e interictal na epilepsia de lobo temporal (ELT. MÉTODO: Foram realizados SPCs ictal e interictal de 24 pacientes com ELT que foram analisados visualmente e com o statistical parametric mapping (SPM2. A análise estatística comparou o grupo de pacientes versus um grupo controle de 50 voluntários. RESULTADOS: Na análise do SPM não foram observadas diferenças significativas no grupo de SPC interictal. No grupo de SPC ictal o SPM revelou hiperperfusão no lobo temporal ipsilateral (foco epileptogênico e também na região parieto-occipital contralateral, porção posterior do cíngulo ipsilateral, lobos occipitais e núcleos da base ipsilateral. O SPC ictal também mostrou áreas de hipoperfusão. CONCLUSÃO: Em uma análise de grupo do SPC ictal de pacientes com ELT, a an

  18. Objective Audiometry using Ear-EEG

    DEFF Research Database (Denmark)

    Christensen, Christian Bech; Kidmose, Preben

    Recently, a novel electroencephalographic (EEG) method called ear-EEG [1], that enable recording of auditory evoked potentials (AEPs) from a personalized earpiece was introduced. Initial investigations show that well established AEPs, such as ASSR and P1-N1-P2 complex can be observed from ear-EEG...

  19. Acute behavioral symptomatology at disappearance of epileptiform EEG abnormality. Paradoxical or "forced" normalization.

    Science.gov (United States)

    Wolf, P

    1991-01-01

    Paradoxical or "forced" normalization of the EEG of patients with epilepsy was first described by Landolt in 1953. It refers to conditions where disappearance of epileptiform discharge from the routine scalp EEG is accompanied by some kind of behavioral disorder. The best known of these is a paranoid psychotic state in clear consciousness, which is also known as "alternative" psychosis. Thus, the issue is related to much older observations which indicated a "biological antagonism" between productive psychotic symptomatology and epileptic seizures, which led to the therapy of psychoses with artificially induced convulsions. Apart from psychotic episodes, the clinical manifestations of PN comprise dysphoric states, hysterical and hypochondriacal syndromes, affective disorders, and miscellanea. PN can be observed in both generalized and localization-related epilepsies as a rare complication. A subset where it is more frequently seen are in adults with persistent absence seizures when the latter become finally controlled by succinimide therapy. These seem to be the drugs with the highest hazard of precipitation of PN, but all other AEDs have also been suspected. Sleep disturbance by succinimide treatment may play a crucial role, but a variety of other factors are also involved, including psychosocial factors. The pathogenesis of this condition has given rise to some debate but remains still unresolved. Eleven of the most important hypotheses have been discussed and seem to converge into a more comprehensive hypothesis which basically assumes that, during PN, the epilepsy is still active subcortically, perhaps with spread of discharge along unusual pathways. This activity is supposed to provide energy and, possibly, some of the symptoms included in the psychotic syndrome. A critical clinical condition results, usually with a dysphoric symptomatology, where a development towards psychosis is impending but still depends on the presence or absence of a variety of risk

  20. Ictal speech and language dysfunction in adult epilepsy: Clinical study of 95 seizures.

    Science.gov (United States)

    Dussaule, C; Cauquil, C; Flamand-Roze, C; Gagnepain, J-P; Bouilleret, V; Denier, C; Masnou, P

    2017-04-01

    To analyze the semiological characteristics of the language and speech disorders arising during epileptic seizures, and to describe the patterns of language and speech disorders that can predict laterality of the epileptic focus. This study retrospectively analyzed 95 consecutive videos of seizures with language and/or speech disorders in 44 patients admitted for diagnostic video-EEG monitoring. Laterality of the epileptic focus was defined according to electro-clinical correlation studies and structural and functional neuroimaging findings. Language and speech disorders were analyzed by a neurologist and a speech therapist blinded to these data. Language and/or speech disorders were subdivided into eight dynamic patterns: pure anterior aphasia; anterior aphasia and vocal; anterior aphasia and "arthria"; pure posterior aphasia; posterior aphasia and vocal; pure vocal; vocal and arthria; and pure arthria. The epileptic focus was in the left hemisphere in more than 4/5 of seizures presenting with pure anterior aphasia or pure posterior aphasia patterns, while discharges originated in the right hemisphere in almost 2/3 of seizures presenting with a pure vocal pattern. No laterality value was found for the other patterns. Classification of the language and speech disorders arising during epileptic seizures into dynamic patterns may be useful for the optimal analysis of anatomo-electro-clinical correlations. In addition, our research has led to the development of standardized tests for analyses of language and speech disorders arising during seizures that can be conducted during video-EEG sessions. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  1. EEG monitoring in postanoxic coma

    NARCIS (Netherlands)

    Cloostermans, M.C.

    2014-01-01

    The electroencephalogram (EEG) contains information that is useful for the prediction of both poor and good neurological outcome in patients with postanoxic encephalopathy after cardiac arrest treated with mild hypothermia. The combined group of iso-electric, low voltage or burst-suppression

  2. PyEEG: an open source Python module for EEG/MEG feature extraction.

    Science.gov (United States)

    Bao, Forrest Sheng; Liu, Xin; Zhang, Christina

    2011-01-01

    Computer-aided diagnosis of neural diseases from EEG signals (or other physiological signals that can be treated as time series, e.g., MEG) is an emerging field that has gained much attention in past years. Extracting features is a key component in the analysis of EEG signals. In our previous works, we have implemented many EEG feature extraction functions in the Python programming language. As Python is gaining more ground in scientific computing, an open source Python module for extracting EEG features has the potential to save much time for computational neuroscientists. In this paper, we introduce PyEEG, an open source Python module for EEG feature extraction.

  3. Serotonergic neurotransmission in the dorsal raphe nucleus recruits in situ 5-HT(2A/2C) receptors to modulate the post-ictal antinociception.

    Science.gov (United States)

    Freitas, Renato Leonardo; Bassi, Gabriel Shimizu; de Oliveira, Ana Maria; Coimbra, Norberto Cysne

    2008-10-01

    The post-ictal immobility syndrome is followed by a significant increase in the nociceptive thresholds in animals and humans. The aim of this study was to assess the involvement of the dorsal raphe nucleus (DRN) in the post-ictal antinociception. The second aim was to study the role of serotonergic intrinsic mechanisms of the DRN in this hypo-algesic phenomenon. Pentylenetetrazole (PTZ), an ionophore GABA-mediated Cl(-) influx antagonist, was peripherally used to induce tonic-clonic seizures in Wistar rats. The nociceptive threshold was measured by the tail-flick test. Neurochemical lesions of the DRN, performed with microinjection of ibotenic acid (1.0 microg/0.2 microL), caused a significant decrease of tonic-clonic seizure-induced antinociception, suggesting the involvement of this nucleus in this antinociceptive process. Microinjections of methysergide (1.0 and 5.0 microg/0.2 microL), a non-selective serotonergic receptor antagonist, into DRN caused a significant decrease in the post-ictal antinociception in seizing animals, compared to controls, in all post-ictal periods presently studied. These findings were corroborated by microinjections of ketanserin (at 1.0 and 5.0 microg/0.2 microL) into DRN. Ketanserin is an antagonist with large affinity for 5-HT(2A/2C) serotonergic receptors, which, in this case, caused a significant decrease in the tail-flick latencies in seizing animals, compared to controls after the first 20 min following tonic-clonic convulsive reactions. These results indicate that serotonergic neurotransmission of the DRN neuronal clusters is involved in the organization of the post-ictal hypo-algesia. The 5-HT(2A/2C) receptors of DRN neurons seem to be critically involved in the increase of nociceptive thresholds following tonic-clonic seizures.

  4. EEG use in a tertiary referral centre.

    LENUS (Irish Health Repository)

    O'Toole, O

    2011-11-15

    The aim of this study was to retrospectively audit all electroencephalograms (EEGs) done over a 2-month period in 2009 by the Neurophysiology Department at Cork University Hospital. There were 316 EEGs performed in total, of which 176\\/316 (56%) were done within 24 hours of request. Out of 316 EEGs, 208 (66%) were considered \\'appropriate\\' by SIGN and NICE guidelines; 79\\/208 (38%) had abnormal EEGs and 28 of these abnormal EEGs had epileptiform features. There were 108\\/316 (34%) \\'inappropriate\\' requests for EEG; of these 15\\/108 (14%) were abnormal. Of the 67\\/316 (21%) patients who had EEGs requested based on a history of syncope\\/funny turns: none of these patients had epileptiform abnormalities on their EEGs. Our audit demonstrates that EEGs are inappropriately over-requested in our institution in particular for cases with reported \\'funny turns\\' and syncope. The yield from EEGs in this cohort of patients was low as would be expected.

  5. Mesio-temporal ictal semiology as an indicator for surgical treatment of epilepsies with large multilobar cerebral lesions.

    Science.gov (United States)

    Catenoix, Hélène; Montavont, Alexandra; Isnard, Jean; Guénot, Marc; Chatillon, Claude-Edouard; Streichenberger, Nathalie; Ryvlin, Philippe; Mauguière, François

    2013-06-01

    Mesio-temporal ictal semiology is sometimes observed in patients with large multilobar lesion. In this situation, surgery is often discarded because of the lesion size and/or suspicion of extended or multifocal epileptogenic areas. In this retrospective study we evaluated the surgical outcome of such patients in order to assess whether the electro-clinical presentation of seizures could be a prognostic marker of surgical outcome. Among the temporal lobe epilepsy population explored in our department between 2000 and 2011 (240 patients), we identified 7 patients who presented an extensive lesion on brain Magnetic Resonance Imaging (MRI) (multilobar in four, hemispheric in two, and bilateral in one). All patients underwent (18)Fluorodeoxyglucose Positron Emission Tomography, which showed large, hemispheric or multilobar, areas of glucose hypometabolism. Because of the large lesion size, all patients were explored by stereoelectroencephalography (SEEG) before taking a decision regarding surgical indication. SEEG confirmed the temporal origin of the seizures and discarded the possibility of multiple epileptogenic zones. A temporal lobectomy, tailored on the basis of SEEG data, was proposed to the seven patients. The seven patients are classified Engel class I after the surgery (mean follow-up: 37.4±22.1 months). Our data thus suggest that, even in the absence of hippocampal MRI abnormality, ictal symptoms compatible with a temporal origin of seizures should be considered as a reliable indicator for surgery eligibility regardless of MRI lesion size. On the basis of our findings, the mesio-temporal semiology of seizures appears as one of the most reliable markers of operability in patients with large MRI lesions. These patients should not be excluded a priori from invasive exploration and surgical treatment, even if a large portion of their lesion is likely to be left in place after surgery. Copyright © 2013 British Epilepsy Association. Published by Elsevier Ltd. All

  6. Drug-resistant parietal epilepsy: polymorphic ictal semiology does not preclude good post-surgical outcome.

    Science.gov (United States)

    Francione, Stefano; Liava, Alexandra; Mai, Roberto; Nobili, Lino; Sartori, Ivana; Tassi, Laura; Scarpa, Pina; Cardinale, Francesco; Castana, Laura; Cossu, Massimo; Lo Russo, Giorgio

    2015-03-01

    We investigated the anatomo-electro-clinical features and clinical outcome of surgical resections strictly confined to the parietal lobe in 40 consecutive patients who received surgery for pharmacoresistant seizures. The population was subcategorized into a paediatric (11 subjects; mean age at surgery: 7.2+/-3.7 years) and an adult group (29 patients; mean age at surgery: 30+/-10.8 years). The paediatric group more frequently exhibited personal antecedents, neurological impairment, high seizure frequency, and dysplastic lesions. Nonetheless, compared with adults, children had better outcome and more frequently reached definitive drug discontinuation after surgery. After a mean follow-up of 9.4 years (range: 3.1-16.7), 30 subjects (75%) were classified as Engel Class I. The presence of multiple types of aura in the same patient, as well as a high incidence of secondary generalization, represented a characteristic feature of parietal seizures and did not correlate negatively with surgical outcome. A total resection of the epileptogenic zone and a localizing/regional interictal EEG were statistically significant predictive factors of outcome. Intracerebral investigation, performed in 55% of cases, contributed to complete tailored resections of the epileptogenic area and determination of prognosis. Frequent subjective manifestations of parietal lobe seizures, such as vertiginous, cephalic and visual-moving sensations, underscore their potential misdiagnosis as non-epileptic events.

  7. Independent EEG sources are dipolar.

    Directory of Open Access Journals (Sweden)

    Arnaud Delorme

    Full Text Available Independent component analysis (ICA and blind source separation (BSS methods are increasingly used to separate individual brain and non-brain source signals mixed by volume conduction in electroencephalographic (EEG and other electrophysiological recordings. We compared results of decomposing thirteen 71-channel human scalp EEG datasets by 22 ICA and BSS algorithms, assessing the pairwise mutual information (PMI in scalp channel pairs, the remaining PMI in component pairs, the overall mutual information reduction (MIR effected by each decomposition, and decomposition 'dipolarity' defined as the number of component scalp maps matching the projection of a single equivalent dipole with less than a given residual variance. The least well-performing algorithm was principal component analysis (PCA; best performing were AMICA and other likelihood/mutual information based ICA methods. Though these and other commonly-used decomposition methods returned many similar components, across 18 ICA/BSS algorithms mean dipolarity varied linearly with both MIR and with PMI remaining between the resulting component time courses, a result compatible with an interpretation of many maximally independent EEG components as being volume-conducted projections of partially-synchronous local cortical field activity within single compact cortical domains. To encourage further method comparisons, the data and software used to prepare the results have been made available (http://sccn.ucsd.edu/wiki/BSSComparison.

  8. EEG correlates of virtual reality hypnosis.

    Science.gov (United States)

    White, David; Ciorciari, Joseph; Carbis, Colin; Liley, David

    2009-01-01

    The study investigated hypnosis-related electroencephalographic (EEG) coherence and power spectra changes in high and low hypnotizables (Stanford Hypnotic Clinical Scale) induced by a virtual reality hypnosis (VRH) induction system. In this study, the EEG from 17 participants (Mean age = 21.35, SD = 1.58) were compared based on their hypnotizability score. The EEG recording associated with a 2-minute, eyes-closed baseline state was compared to the EEG during a hypnosis-related state. This novel induction system was able to produce EEG findings consistent with previous hypnosis literature. Interactions of significance were found with EEG beta coherence. The high susceptibility group (n = 7) showed decreased coherence, while the low susceptibility group (n = 10) demonstrated an increase in coherence between medial frontal and lateral left prefrontal sites. Methodological and efficacy issues are discussed.

  9. Modeling epileptic brain states using EEG spectral analysis and topographic mapping.

    Science.gov (United States)

    Direito, Bruno; Teixeira, César; Ribeiro, Bernardete; Castelo-Branco, Miguel; Sales, Francisco; Dourado, António

    2012-09-30

    Changes in the spatio-temporal behavior of the brain electrical activity are believed to be associated to epileptic brain states. We propose a novel methodology to identify the different states of the epileptic brain, based on the topographic mapping of the time varying relative power of delta, theta, alpha, beta and gamma frequency sub-bands, estimated from EEG. Using normalized-cuts segmentation algorithm, points of interest are identified in the topographic mappings and their trajectories over time are used for finding out relations with epileptogenic propagations in the brain. These trajectories are used to train a Hidden Markov Model (HMM), which models the different epileptic brain states and the transition among them. Applied to 10 patients suffering from focal seizures, with a total of 30 seizures over 497.3h of data, the methodology shows good results (an average point-by-point accuracy of 89.31%) for the identification of the four brain states--interictal, preictal, ictal and postictal. The results suggest that the spatio-temporal dynamics captured by the proposed methodology are related to the epileptic brain states and transitions involved in focal seizures. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Juvenile myoclonic epilepsy: clinical and EEG features

    DEFF Research Database (Denmark)

    Pedersen, S B; Petersen, K A

    1998-01-01

    We aimed to characterize the clinical profile and EEG features of 43 patients with juvenile myoclonic epilepsy. In a retrospective design we studied the records of, and re-interviewed, 43 patients diagnosed with JME from the epilepsy clinic data base. Furthermore, available EEGs were re-evaluated...... were sleep deprivation (84%), stress (70%), and alcohol consumption (51%). EEG findings included rapid spike-wave and polyspike-wave....

  11. An EEG Data Investigation Using Only Artifacts

    Science.gov (United States)

    2017-02-22

    EEG Data Investigation Using Only Artifacts 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 1 Chelsey...ORGANIZATION NAME(S) AND ADDRESS(ES) AND ADDRESS(ES) 1 Ball Aerospace – 2875 Presidential Drive , Fairborn, Ohio 45324 2 Oak Ridge Institute for Science...electroencephalogram (EEG) is a positive indicator of mental workload. However, EEG signals are easily affected by artifacts . An artifact mediation

  12. Tele-transmission of EEG recordings.

    Science.gov (United States)

    Lemesle, M; Kubis, N; Sauleau, P; N'Guyen The Tich, S; Touzery-de Villepin, A

    2015-03-01

    EEG recordings can be sent for remote interpretation. This article aims to define the tele-EEG procedures and technical guidelines. Tele-EEG is a complete medical act that needs to be carried out with the same quality requirements as a local one in terms of indications, formulation of the medical request and medical interpretation. It adheres to the same quality requirements for its human resources and materials. It must be part of a medical organization (technical and medical network) and follow all rules and guidelines of good medical practices. The financial model of this organization must include costs related to performing the EEG recording, operating and maintenance of the tele-EEG network and medical fees of the physician interpreting the EEG recording. Implementing this organization must be detailed in a convention between all parties involved: physicians, management of the healthcare structure, and the company providing the tele-EEG service. This convention will set rules for network operation and finance, and also the continuous training of all staff members. The tele-EEG system must respect all rules for safety and confidentiality, and ensure the traceability and storing of all requests and reports. Under these conditions, tele-EEG can optimize the use of human resources and competencies in its zone of utilization and enhance the organization of care management. Copyright © 2015. Published by Elsevier SAS.

  13. Test-retest reliability of cognitive EEG

    Science.gov (United States)

    McEvoy, L. K.; Smith, M. E.; Gevins, A.

    2000-01-01

    OBJECTIVE: Task-related EEG is sensitive to changes in cognitive state produced by increased task difficulty and by transient impairment. If task-related EEG has high test-retest reliability, it could be used as part of a clinical test to assess changes in cognitive function. The aim of this study was to determine the reliability of the EEG recorded during the performance of a working memory (WM) task and a psychomotor vigilance task (PVT). METHODS: EEG was recorded while subjects rested quietly and while they performed the tasks. Within session (test-retest interval of approximately 1 h) and between session (test-retest interval of approximately 7 days) reliability was calculated for four EEG components: frontal midline theta at Fz, posterior theta at Pz, and slow and fast alpha at Pz. RESULTS: Task-related EEG was highly reliable within and between sessions (r0.9 for all components in WM task, and r0.8 for all components in the PVT). Resting EEG also showed high reliability, although the magnitude of the correlation was somewhat smaller than that of the task-related EEG (r0.7 for all 4 components). CONCLUSIONS: These results suggest that under appropriate conditions, task-related EEG has sufficient retest reliability for use in assessing clinical changes in cognitive status.

  14. EEG entropy measures in anesthesia

    Science.gov (United States)

    Liang, Zhenhu; Wang, Yinghua; Sun, Xue; Li, Duan; Voss, Logan J.; Sleigh, Jamie W.; Hagihira, Satoshi; Li, Xiaoli

    2015-01-01

    Highlights: ► Twelve entropy indices were systematically compared in monitoring depth of anesthesia and detecting burst suppression.► Renyi permutation entropy performed best in tracking EEG changes associated with different anesthesia states.► Approximate Entropy and Sample Entropy performed best in detecting burst suppression. Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs' effect is lacking. In this study, we compare the capability of 12 entropy indices for monitoring depth of anesthesia (DoA) and detecting the burst suppression pattern (BSP), in anesthesia induced by GABAergic agents. Methods: Twelve indices were investigated, namely Response Entropy (RE) and State entropy (SE), three wavelet entropy (WE) measures [Shannon WE (SWE), Tsallis WE (TWE), and Renyi WE (RWE)], Hilbert-Huang spectral entropy (HHSE), approximate entropy (ApEn), sample entropy (SampEn), Fuzzy entropy, and three permutation entropy (PE) measures [Shannon PE (SPE), Tsallis PE (TPE) and Renyi PE (RPE)]. Two EEG data sets from sevoflurane-induced and isoflurane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, pharmacokinetic/pharmacodynamic (PK/PD) modeling and prediction probability (Pk) analysis were applied. The multifractal detrended fluctuation analysis (MDFA) as a non-entropy measure was compared. Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline variability, higher coefficient of determination (R2) and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an advantage in computation

  15. Continuous EEG Monitoring in Aneurysmal Subarachnoid Hemorrhage

    DEFF Research Database (Denmark)

    Kondziella, Daniel; Friberg, Christian Kærsmose; Wellwood, Ian

    2015-01-01

    BACKGROUND: Continuous EEG (cEEG) may allow monitoring of patients with aneurysmal subarachnoid hemorrhage (SAH) for delayed cerebral ischemia (DCI) and seizures, including non-convulsive seizures (NCSz), and non-convulsive status epilepticus (NCSE). We aimed to evaluate: (a) the diagnostic...

  16. EEG applications for sport and performance.

    Science.gov (United States)

    Thompson, Trevor; Steffert, Tony; Ros, Tomas; Leach, Joseph; Gruzelier, John

    2008-08-01

    One approach to understanding processes that underlie skilled performing has been to study electrical brain activity using electroencephalography (EEG). A notorious problem with EEG is that genuine cerebral data is often contaminated by artifacts of non-cerebral origin. Unfortunately, such artifacts tend to be exacerbated when the subject is in motion, meaning that obtaining reliable data during exercise is inherently problematic. These problems may explain the limited number of studies using EEG as a methodological tool in the sports sciences. This paper discusses how empirical studies have generally tackled the problem of movement artifact by adopting alternative paradigms which avoid recording during actual physical exertion. Moreover, the specific challenges that motion presents to obtaining reliable EEG data are discussed along with practical and computational techniques to confront these challenges. Finally, as EEG recording in sports is often underpinned by a desire to optimise performance, a brief review of EEG-biofeedback and peak performance studies is also presented. A knowledge of practical aspects of EEG recording along with the advent of new technology and increasingly sophisticated processing models offer a promising approach to minimising, if perhaps not entirely circumventing, the problem of obtaining reliable EEG data during motion.

  17. Juvenile myoclonic epilepsy: clinical and EEG features

    DEFF Research Database (Denmark)

    Pedersen, S B; Petersen, K A

    1998-01-01

    We aimed to characterize the clinical profile and EEG features of 43 patients with juvenile myoclonic epilepsy. In a retrospective design we studied the records of, and re-interviewed, 43 patients diagnosed with JME from the epilepsy clinic data base. Furthermore, available EEGs were re-evaluated...... were sleep deprivation (84%), stress (70%), and alcohol consumption (51%). EEG findings included rapid spike-wave and polyspike-wave.......We aimed to characterize the clinical profile and EEG features of 43 patients with juvenile myoclonic epilepsy. In a retrospective design we studied the records of, and re-interviewed, 43 patients diagnosed with JME from the epilepsy clinic data base. Furthermore, available EEGs were re...

  18. Effect of a nanostructured dendrimer-naloxonazine complex on endogenous opioid peptides μ1 receptor-mediated post-ictal antinociception.

    Science.gov (United States)

    Felippotti, Tatiana Tocchini; do Carmo, Devaney Ribeiro; Paim, Leonardo Lataro; Stradiotto, Nelson Ramos; Bicalho, Urquisa de Oliveira; Parada, Carlos Amílcar; Grillo, Renato; Fraceto, Leonardo Fernandes; Coimbra, Norberto Cysne

    2011-12-01

    The aim of this study was to investigate the capacity of the host dendrimer DAB-Am-16 as a drug carrier to reduce the time required for the encapsulated naloxonaxine to establish an irreversible covalent bond with μ(1)-opioid receptor (resulting in a pharmacologically selective effect). The efficacy of dendrimer-naloxonazine nanocomplex (DNC) was studied in antinociception induced by convulsions elicited by intraperitoneal (IP) administration of pentylenetetrazole, and analgesia was measured by the tail-flick test. We found that animals showed increased tail-flick latencies following convulsions. Furthermore, acute pre-treatment (10 minutes) with DNC, but not with naloxonazine alone, antagonized post-ictal analgesia in comparison with control pre-treatment. However, naloxonazine treatment 24 hours before PTZ decreased post-ictal antinociception, but DNC failed to antagonize tonic-clonic seizure-induced analgesia. In addition, according to Racine's index of seizure severity, naloxonazine, DAB-Am-16 dendrimer or DNC did not influence seizure severity when administered either 10 minutes or 24 hours before PTZ. This study characterizes the effect of a dendrimer-naloxonazine complex on μ1 receptor-mediated post-ictal antinociception in an animal model of seizure disorder. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Trends in EEG source localization.

    Science.gov (United States)

    Koles, Z J

    1998-02-01

    The concepts underlying the quantitative localization of the sources of the EEG inside the brain are reviewed along with the current and emerging approaches to the problem. The concepts mentioned include monopolar and dipolar source models and head models ranging from the spherical to the more realistic based on boundary and finite elements. The forward and inverse problems in electroencephalography are discussed, including the non-uniqueness of the inverse problem. The approaches to the solution of the inverse problem described include single and multiple time-slice localization, equivalent dipole localization and the weighted minimum norm. The multiple time-slice localization approach is highlighted as probably the best available at this time and is discussed in terms of the spatiotemporal model of the EEG. The effect of noise corruption, artifacts and the number of recording electrodes on the accuracy of source localization is also mentioned. It is suggested that the main appeal of the minimum norm is that it does not assume a model for the sources and provides an estimate of the current density everywhere in the three dimensional volume of the head.

  20. Emergence EEG pattern classification in sevoflurane anesthesia.

    Science.gov (United States)

    Liang, Zhenhu; Huang, Cheng; Li, Yongwang; Hight, Darren F; Voss, Logan J; Sleigh, Jamie W; Li, Xiaoli; Bai, Yang

    2018-03-07

    Objective. Significant spectral characteristics of electroencephalogram (EEG) patterns exist in individual patients during re-establishing consciousness after general anesthesia. However, these EEG patterns cannot be quantitatively identified using commercially available depth of anesthesia (DoA) monitors. This study proposed an effective classification method and indices to classify these patterns among patients. Approach. Four types of emergence EEG patterns were identified based on EEG data set from 52patients undergoing sevoflurane general anesthesia from two hospitals. Then, the relative power spectrum density (RPSD) of five frequency sub-bands of clinical interest (delta, theta, alpha, beta, and gamma) were selected for emergence state analysis. Finally, the genetic algorithm support vector machine (GA-SVM) was used to identify the emergence EEG patterns. Performance was reported in terms of sensitivity (SE), specificity (SP) and accuracy (AC). Main results. The combination of the mean and mode of RPSD in delta and alpha band (P (delta)/P (alpha) performed the best with the GA-SVM classification. AC indices obtained by GA-SVM across the four patterns were 90.64±7.61, 81.79±5.84, 82.14±7.99, and 72.86±11.11 respectively. Furthermore, the emergence time of the patients with EEG emergence pattern I and III increased with the increasing of patients' age. While for the patients with EEG emergence pattern IV, the emergence time positively correlates with the patients' age which less than 50, and negatively correlates with the patients' age which more than 50. Significance. The mean and mode of P (delta)/P (alpha) is a useful index to classify the different emergence EEG patterns. In addition, the EEG emergence patterns may correlate with underlying neural substrate which related with patients' age. © 2018 Institute of Physics and Engineering in Medicine.

  1. Signal Quality Evaluation of Emerging EEG Devices

    Directory of Open Access Journals (Sweden)

    Thea Radüntz

    2018-02-01

    Full Text Available Electroencephalogram (EEG registration as a direct measure of brain activity has unique potentials. It is one of the most reliable and predicative indicators when studying human cognition, evaluating a subject's health condition, or monitoring their mental state. Unfortunately, standard signal acquisition procedures limit the usability of EEG devices and narrow their application outside the lab. Emerging sensor technology allows gel-free EEG registration and wireless signal transmission. Thus, it enables quick and easy application of EEG devices by users themselves. Although a main requirement for the interpretation of an EEG is good signal quality, there is a lack of research on this topic in relation to new devices. In our work, we compared the signal quality of six very different EEG devices. On six consecutive days, 24 subjects wore each device for 60 min and completed tasks and games on the computer. The registered signals were evaluated in the time and frequency domains. In the time domain, we examined the percentage of artifact-contaminated EEG segments and the signal-to-noise ratios. In the frequency domain, we focused on the band power variation in relation to task demands. The results indicated that the signal quality of a mobile, gel-based EEG system could not be surpassed by that of a gel-free system. However, some of the mobile dry-electrode devices offered signals that were almost comparable and were very promising. This study provided a differentiated view of the signal quality of emerging mobile and gel-free EEG recording technology and allowed an assessment of the functionality of the new devices. Hence, it provided a crucial prerequisite for their general application, while simultaneously supporting their further development.

  2. Involvement of 5-HT(2) serotonergic receptors of the nucleus raphe magnus and nucleus reticularis gigantocellularis/paragigantocellularis complex neural networks in the antinociceptive phenomenon that follows the post-ictal immobility syndrome.

    Science.gov (United States)

    de Oliveira, Rithiele Cristina; de Oliveira, Ricardo; Ferreira, Célio Marcos Dos Reis; Coimbra, Norberto Cysne

    2006-09-01

    The post-ictal immobility syndrome is followed by a significant increase in the nociceptive thresholds in animals and men. In this interesting post-ictal behavioral response, endogenous opioid peptides-mediated mechanisms, as well as cholinergic-mediated antinociceptive processes, have been suggested. However, considering that many serotonergic descending pathways have been implicated in antinociceptive reactions, the aim of the present work is to investigate the involvement of 5-HT(2)-serotonergic receptor subfamily in the post-ictal antinociception. The analgesia was measured by the tail-flick test in seven or eight Wistar rats per group. Convulsions were followed by statistically significant increase in the tail-flick latencies (TFL), at least for 120 min of the post-ictal period. Male Wistar rats were submitted to stereotaxic surgery for introduction of a guide-cannula in the rhombencephalon, aiming either the nucleus raphe magnus (NRM) or the gigantocellularis complex. In independent groups of animals, these nuclei were neurochemically lesioned with a unilateral microinjection of ibotenic acid (1.0 microg/0.2 microL). The neuronal damage of either the NRM or nucleus reticularis gigantocellularis/paragigantocellularis complex decreased the post-ictal analgesia. Also, in other independent groups, central administration of ritanserin (5.0 microg/0.2 microL) or physiological saline into each of the reticular formation nuclei studied caused a statistically significant decrease in the TFL of seizing animals, as compared to controls, in all post-ictal periods studied. These results indicate that serotonin input-connected neurons of the pontine and medullarly reticular nuclei may be involved in the post-ictal analgesia.

  3. PyEEG: An Open Source Python Module for EEG/MEG Feature Extraction

    Directory of Open Access Journals (Sweden)

    Forrest Sheng Bao

    2011-01-01

    Full Text Available Computer-aided diagnosis of neural diseases from EEG signals (or other physiological signals that can be treated as time series, e.g., MEG is an emerging field that has gained much attention in past years. Extracting features is a key component in the analysis of EEG signals. In our previous works, we have implemented many EEG feature extraction functions in the Python programming language. As Python is gaining more ground in scientific computing, an open source Python module for extracting EEG features has the potential to save much time for computational neuroscientists. In this paper, we introduce PyEEG, an open source Python module for EEG feature extraction.

  4. Analyzing Electroencephalogram Signal Using EEG Lab

    Directory of Open Access Journals (Sweden)

    Mukesh BHARDWAJ

    2009-01-01

    Full Text Available The EEG is composed of electrical potentials arising from several sources. Each source (including separate neural clusters, blink artifact or pulse artifact forms a unique topography onto the scalp – ‘scalp map‘. Scalp map may be 2-D or 3-D.These maps are mixed according to the principle of linear superposition. Independent component analysis (ICA attempts to reverse the superposition by separating the EEG into mutually independent scalp maps, or components. MATLAB toolbox and graphic user interface, EEGLAB is used for processing EEG data of any number of channels. Wavelet toolbox has been used for 2-D signal analysis.

  5. Intracranial EEG Connectivity Analysis and Result Imaging

    Czech Academy of Sciences Publication Activity Database

    Klimeš, Petr; Janeček, Jiří; Jurák, Pavel; Halámek, Josef; Chládek, Jan; Brázdil, M.

    2012-01-01

    Roč. 2, č. 4 (2012), s. 275-279 ISSN 2010-3638 Institutional support: RVO:68081731 Keywords : Connectivity * Correlation * Intracranial EEG * Signal Processing Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  6. Two channel EEG thought pattern classifier.

    Science.gov (United States)

    Craig, D A; Nguyen, H T; Burchey, H A

    2006-01-01

    This paper presents a real-time electro-encephalogram (EEG) identification system with the goal of achieving hands free control. With two EEG electrodes placed on the scalp of the user, EEG signals are amplified and digitised directly using a ProComp+ encoder and transferred to the host computer through the RS232 interface. Using a real-time multilayer neural network, the actual classification for the control of a powered wheelchair has a very fast response. It can detect changes in the user's thought pattern in 1 second. Using only two EEG electrodes at positions O(1) and C(4) the system can classify three mental commands (forward, left and right) with an accuracy of more than 79 %

  7. Computerized EEG: predictor of outcome in schizophrenia.

    Science.gov (United States)

    Itil, T M; Marasa, J; Saletu, B; Davis, S; Mucciardi, A N

    1975-03-01

    Based on a double blind cross-over study, it was determined that schizophrenic patient who have more high frequency fast activity and a lesser degree of alpha and slow waves in computerized EEG before the treatment have a better therapeutic outcome to the major tranquilizer (neuroleptic) treatment. The correlation between pretreatment high frequency computer EEG measurements and better therapeutic outcome reached the level of statistical significance. "Therapy resistant" schizophrenic patients were characterized by a lesser degree of very fast beta activity, more alpha waves and slow waves, higher amplitudes in computer EEG, and a lesser degree of acute (florid) psychotic symptomatology but more "negative" symptoms such as motor retardation and blunted affect. One of the most striking results of the study is the finding that schizophrenic patients with certain psychopathological profiles also have similar computer EEG profiles.

  8. Predictive Values of Electroencephalography (EEG) in Epilepsy ...

    African Journals Online (AJOL)

    Predictive Values of Electroencephalography (EEG) in Epilepsy Patients with Abnormal Behavioural Symptoms. OR Obiako, SO Adeyemi, TL Sheikh, LF Owolabi, MA Majebi, MO Gomina, F Adebayo, EU Iwuozo ...

  9. EEG Correlates of Ten Positive Emotions

    OpenAIRE

    Hu, Xin; Yu, Jianwen; Song, Mengdi; Yu, Chun; Wang, Fei; Sun, Pei; Wang, Daifa; Zhang, Dan

    2017-01-01

    Compared with the well documented neurophysiological findings on negative emotions, much less is known about positive emotions. In the present study, we explored the EEG correlates of ten different positive emotions (joy, gratitude, serenity, interest, hope, pride, amusement, inspiration, awe, and love). A group of 20 participants were invited to watch 30 short film clips with their EEGs simultaneously recorded. Distinct topographical patterns for different positive emotions were found for th...

  10. Sleep EEG of Microcephaly in Zika Outbreak.

    Science.gov (United States)

    Kanda, Paulo Afonso Medeiros; Aguiar, Aline de Almeida Xavier; Miranda, Jose Lucivan; Falcao, Alexandre Loverde; Andrade, Claudia Suenia; Reis, Luigi Neves Dos Santos; Almeida, Ellen White R Bacelar; Bello, Yanes Brum; Monfredinho, Arthur; Kanda, Rafael Guimaraes

    2018-01-01

    Microcephaly (MC), previously considered rare, is now a health emergency of international concern because of the devastating Zika virus pandemic outbreak of 2015. The authors describe the electroencephalogram (EEG) findings in sleep EEG of epileptic children who were born with microcephaly in areas of Brazil with active Zika virus transmission between 2014 and 2017. The authors reviewed EEGs from 23 children. Nine were females (39.2%), and the age distribution varied from 4 to 48 months. MC was associated with mother positive serology to toxoplasmosis (toxo), rubella (rub), herpes, and dengue (1 case); toxo (1 case); chikungunya virus (CHIKV) (1 case); syphilis (1 case); and Zika virus (ZIKV) (10 cases). In addition, 1 case was associated with perinatal hypoxia and causes of 9 cases remain unknown. The main background EEG abnormality was diffuse slowing (10 cases), followed by classic (3 cases) and modified (5 cases) hypsarrhythmia. A distinct EEG pattern was seen in ZIKV (5 cases), toxo (2 cases), and undetermined cause (1 case). It was characterized by runs of frontocentrotemporal 4.5-13 Hz activity (7 cases) or diffuse and bilateral runs of 18-24 Hz (1 case). In ZIKV, this rhythmic activity was associated with hypsarrhythmia or slow background. Further studies are necessary to determine if this association is suggestive of ZIKV infection. The authors believe that EEG should be included in the investigation of all newly diagnosed congenital MC, especially those occurring in areas of autochthonous transmission of ZIKV.

  11. Cognitive neuroscience of creativity: EEG based approaches.

    Science.gov (United States)

    Srinivasan, Narayanan

    2007-05-01

    Cognitive neuroscience of creativity has been extensively studied using non-invasive electrical recordings from the scalp called electroencephalograms (EEGs) and event related potentials (ERPs). The paper discusses major aspects of performing research using EEG/ERP based experiments including the recording of the signals, removing noise, estimating ERP signals, and signal analysis for better understanding of the neural correlates of processes involved in creativity. Important factors to be kept in mind to record clean EEG signal in creativity research are discussed. The recorded EEG signal can be corrupted by various sources of noise and methodologies to handle the presence of unwanted artifacts and filtering noise are presented followed by methods to estimate ERPs from the EEG signals from multiple trials. The EEG and ERP signals are further analyzed using various techniques including spectral analysis, coherence analysis, and non-linear signal analysis. These analysis techniques provide a way to understand the spatial activations and temporal development of large scale electrical activity in the brain during creative tasks. The use of this methodology will further enhance our understanding the processes neural and cognitive processes involved in creativity.

  12. Clinical and eeg analysis of mesial and lateral temporal lobe seizures Análise clínica e eletrencefalográfica de crises epilépticas temporais de origem mesial e lateral

    Directory of Open Access Journals (Sweden)

    FÁBIO GALVÃO DANTAS

    1998-09-01

    Full Text Available The analysis of the temporal lobe seizures through video-EEG systems shows that they often consist of a sequence of clinical and EEG features which may suggest the localization and the lateralization of the epileptogenic lobe. We analyzed clinical and EEG features of 50 temporal lobe seizures which were separated in group 1 with 25 patients (related to mesial temporal sclerosis and group 2 with 25 patients (other neocortical temporal lesions. Among the auras, the epigastric type was the most frequent and predominated in group 1. There were differences between the two groups, considering dystonic and tonic posturing and versive head and eye movements. Dystonic posturing was always contralateral to the ictal onset and was considered the most useful lateralizing clinical feature. Ictal speech, spitting and blinking automatisms, prolonged disorientation for place and a greatest percentage of postictal language preservation occurred in right temporal seizures. Postictal aphasia and global disorientation predominated in left temporal seizures. EEG was important for lateralizing the epileptogenic lobe, specially considering rhythmic ictal activity and postictal findings.As crises epilépticas do lobo temporal tendem a seguir uma sequência previsível de eventos clínicos e eletrencefalográficos, cuja análise, preferencialmente através de sistemas de vídeo-EEG, sugere a localização e a lateralização do lobo epileptogênico. Para este estudo, foram analisadas 50 crises epilépticas do lobo temporal, do ponto de vista clínico e eletrencefalográfico, sendo 25 relacionadas a esclerose mesial (grupo 1 e 25 a patologias neocorticais (grupo 2. Auras abdominais foram as mais frequentes, predominando no grupo 1. Houve diferenças entre os dois grupos, quanto à instalação e duração da postura distônica, à postura tônica e à versão oculocefálica. Postura distônica unilateral foi o mais importante fenômeno clínico lateralizatório, sempre

  13. Neurophysiology of juvenile myoclonic epilepsy: EEG-based network and graph analysis of the interictal and immediate preictal states.

    Science.gov (United States)

    Clemens, B; Puskás, S; Besenyei, M; Spisák, T; Opposits, G; Hollódy, K; Fogarasi, A; Fekete, I; Emri, M

    2013-10-01

    The neuronal mechanisms of enduring seizure propensity and seizure precipitation in juvenile myoclonic epilepsy (JME) are not known. We investigated these issues, within the framework of the "network concept" of epilepsy. Design1: 19, unmedicated JME patients were compared with nineteen, age-, and sex-matched normal control persons (NC). A total of 120s, artifact-free, paroxysm-free, eyes-closed, resting state EEG background activity was analyzed for each person. Design2: interictal and immediate preictal periods of the JME patients were compared in order to explore interictal-preictal network differences. For both comparison designs, statistically significant differences of EEG functional connectivity (EEGfC), nodal and global graph parameters were evaluated. Design1: maximum abnormalities were: increased delta, theta, alpha1 EEGfC and decreased alpha2 and beta EEGfC in the JME group as compared to the NC group, mainly among cortical areas that are involved in sensory-motor integration. Nodal degree and efficiency of three, medial, basal frontal nodes were greater in JME than in NC, in the alpha1 band. Design2: preictal delta EEGfC showed further increase in the above-mentioned areas, as compared to the interictal state. Increased EEGfC indicates a hypercoupled state among the specified cortical areas. This interictal abnormality further increases in the preictal state. Nodal graph statistics indicates abnormal neuronal dynamics in the cortical area that is the ictal onset zone in JME. Interictal and preictal neuronal dysfunction has been described in terms of network dynamics and topography in JME patients. Forthcoming investigations of seizure precipitation and therapeutic drug effects are encouraged on this basis. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Hippocampal EEG and behaviour in dog. II. Hippocampal EEG correlates with elementary motor acts

    NARCIS (Netherlands)

    Arnolds, D.E.A.T.; Lopes da Silva, F.H.; Aitink, J.W.; Kamp, A.

    A positive correlation has been shown between the speed of forced stepping on a conveyor belt and the amplitude and frequency of the concomitant hippocampal EEG. Significant modulation in the spectral properties of the dog's hippocampal EEG has been found in relation to 3 elementary motor acts:

  15. Integration of differences in EEG analysis reveals changes in human EEG caused by microwave.

    Science.gov (United States)

    Bachmann, Maie; Lass, Jaanus; Kalda, Jaan; Säkki, Maksim; Tomson, Ruth; Tuulik, Viiu; Hinrikus, Hiie

    2006-01-01

    Three different methods in combination with integration of differences in signals were applied for EEG analysis to distinguish changes in EEG caused by microwave: S-parameter, power spectral density and length distribution of low variability periods. The experiments on the effect of modulated low-level microwaves on human EEG were carried out on four different groups of healthy volunteers exposed to 450 MHz microwave radiation modulated with 7 Hz, 14 Hz, 21 Hz, 40 Hz, 70 Hz, 217 or 1000 Hz frequencies. The field power density at the scalp was 0.16 mW/cm2. The EEG analysis performed for individuals with three different methods showed that statistically significant changes occur in the EEG rhythms energy and dynamics between 12% and 30% of subjects.

  16. The best time for EEG recording in febrile seizure.

    Science.gov (United States)

    Karimzadeh, Parvaneh; Rezayi, Alireza; Togha, Mansoureh; Ahmadabadi, Farzad; Derakhshanfar, Hojjat; Azargashb, Eznollah; Khodaei, Fatemeh

    2014-01-01

    Some studies suggest that detection of epileptic discharge is unusual during the first postictal week of febrile seizure and others believe that EEGs carried out on the day of the seizure are abnormal in as many as 88% of the patients. In this study, we intend to compare early and late EEG abnormalities in febrile seizure. EEG was recorded during daytime sleep, 24-48 hours (early EEG) and 2 weeks (late EEG) after the seizure in 36 children with febrile seizure (FS), aged between 3 months and 6 years. EEGs that showed generalized or focal spikes, sharp, spike wave complex, and slowing were considered as abnormal EEG. Abnormalities of the first EEG were compared with those of second EEG. The most common abnormal epileptiform discharges recorded in the early EEG were slow waves (27.6%) and sharp waves in late EEG (36%). Distribution of abnormalities in early and late EEG showed no significant statistical difference. The early and late EEG recording had the same results in patient with febrile seizure.

  17. EEG Correlates of Ten Positive Emotions.

    Science.gov (United States)

    Hu, Xin; Yu, Jianwen; Song, Mengdi; Yu, Chun; Wang, Fei; Sun, Pei; Wang, Daifa; Zhang, Dan

    2017-01-01

    Compared with the well documented neurophysiological findings on negative emotions, much less is known about positive emotions. In the present study, we explored the EEG correlates of ten different positive emotions (joy, gratitude, serenity, interest, hope, pride, amusement, inspiration, awe, and love). A group of 20 participants were invited to watch 30 short film clips with their EEGs simultaneously recorded. Distinct topographical patterns for different positive emotions were found for the correlation coefficients between the subjective ratings on the ten positive emotions per film clip and the corresponding EEG spectral powers in different frequency bands. Based on the similarities of the participants' ratings on the ten positive emotions, these emotions were further clustered into three representative clusters, as 'encouragement' for awe, gratitude, hope, inspiration, pride, 'playfulness' for amusement, joy, interest, and 'harmony' for love, serenity. Using the EEG spectral powers as features, both the binary classification on the higher and lower ratings on these positive emotions and the binary classification between the three positive emotion clusters, achieved accuracies of approximately 80% and above. To our knowledge, our study provides the first piece of evidence on the EEG correlates of different positive emotions.

  18. Investigating reading comprehension through EEG

    Directory of Open Access Journals (Sweden)

    Luciane Baretta

    2012-12-01

    Full Text Available http://dx.doi.org/10.5007/2175-8026.2012n63p69   Experimental studies point that different factors can influence reading comprehension, such as the topic, text type, reading task, and others. The advances in technologies for the past decades have provided researchers with several possibilities to investigate what goes on in one’s brain since their eyes meet the page until comprehension is achieved. Since the mid-80’s, numerous studies have been conducted with the use of the electroencephalogram (EEG to investigate the process of reading, through the analysis of different components – n400, n100 or n1, P2, among others. These components reveal, for example, how the brain integrates the meaning of a specific word in the semantic context of a given sentence.  based on previous studies, which demonstrate that different types of words affect cognitive load, this paper aims at investigating how the brain processes function and content words inserted in expository and narrative texts with suitable / unsuitable conclusions. results showed that the type of text and word influence the cognitive load in different scalp areas (midline, right and left hemispheres. The  n1s were more pronounced to the content words inserted in narrative texts and to the function words inserted in the expository type of texts, corroborating former studies.

  19. Insights from intermittent binocular rivalry and EEG

    Directory of Open Access Journals (Sweden)

    Michael A Pitts

    2011-09-01

    Full Text Available Novel stimulation and analytical approaches employed in EEG studies of ambiguous figures have recently been applied to binocular rivalry. The combination of intermittent stimulus presentation and EEG source imaging has begun to shed new light on the neural underpinnings of binocular rivalry. Here, we review the basics of the intermittent paradigm and highlight methodological issues important for interpreting previous results and designing future experiments. We then outline current analytical approaches, including EEG microstates, event-related potentials, and statistically-based source estimation, and propose a spatio-temporal model that integrates findings from several studies. Finally, we discuss the advantages and limitations of using binocular rivalry as a tool to investigate the neural basis of perceptual awareness.

  20. The Mozart Effect: A quantitative EEG study.

    Science.gov (United States)

    Verrusio, Walter; Ettorre, Evaristo; Vicenzini, Edoardo; Vanacore, Nicola; Cacciafesta, Mauro; Mecarelli, Oriano

    2015-09-01

    The aim of this study is to investigate the influence of Mozart's music on brain activity through spectral analysis of the EEG in young healthy adults (Adults), in healthy elderly (Elderly) and in elderly with Mild Cognitive Impairment (MCI). EEG recording was performed at basal rest conditions and after listening to Mozart's K448 or "Fur Elise" Beethoven's sonatas. After listening to Mozart, an increase of alpha band and median frequency index of background alpha rhythm activity (a pattern of brain wave activity linked to memory, cognition and open mind to problem solving) was observed both in Adults and in Elderly. No changes were observed in MCI. After listening to Beethoven, no changes in EEG activity were detected. This results may be representative of the fact that said Mozart's music is able to "activate" neuronal cortical circuits related to attentive and cognitive functions. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. EEG-guided meditation: A personalized approach.

    Science.gov (United States)

    Fingelkurts, Andrew A; Fingelkurts, Alexander A; Kallio-Tamminen, Tarja

    2015-12-01

    The therapeutic potential of meditation for physical and mental well-being is well documented, however the possibility of adverse effects warrants further discussion of the suitability of any particular meditation practice for every given participant. This concern highlights the need for a personalized approach in the meditation practice adjusted for a concrete individual. This can be done by using an objective screening procedure that detects the weak and strong cognitive skills in brain function, thus helping design a tailored meditation training protocol. Quantitative electroencephalogram (qEEG) is a suitable tool that allows identification of individual neurophysiological types. Using qEEG screening can aid developing a meditation training program that maximizes results and minimizes risk of potential negative effects. This brief theoretical-conceptual review provides a discussion of the problem and presents some illustrative results on the usage of qEEG screening for the guidance of mediation personalization. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Modular, bluetooth enabled, wireless electroencephalograph (EEG) platform.

    Science.gov (United States)

    Lovelace, Joseph A; Witt, Tyler S; Beyette, Fred R

    2013-01-01

    A design for a modular, compact, and accurate wireless electroencephalograph (EEG) system is proposed. EEG is the only non-invasive measure for neuronal function of the brain. Using a number of digital signal processing (DSP) techniques, this neuronal function can be acquired and processed into meaningful representations of brain activity. The system described here utilizes Bluetooth to wirelessly transmit the digitized brain signal for an end application use. In this way, the system is portable, and modular in terms of the device to which it can interface. Brain Computer Interface (BCI) has become a popular extension of EEG systems in modern research. This design serves as a platform for applications using BCI capability.

  3. EEG. Renewables Act. Comment. 3. new rev. and enl. ed.; EEG. Erneuerbare-Energien-Gesetz. Kommentar

    Energy Technology Data Exchange (ETDEWEB)

    Frenz, Walter [Rheinisch-Westfaelische Technische Hochschule (RWTH), Aachen (Germany). Lehr- und Forschungsgebiet Berg-, Umwelt- und Europarecht; Mueggenborg, Hans-Juergen (eds.) [Kassel Univ. (Germany)

    2013-05-01

    Like hardly any other law, the Renewable Energy Sources Law (EEG) is a subject to continuing modifications. This makes the application of the already complicated regulations even for experts to a special challenge. With the proven Berliner comment EEG, now a reliable companion through the bureaucratic jungle is available. All regulations of the EEG are commented precisely and easily to understand by profound experts. An extensive selection of terminology enables a rapid orientation within this book. In addition to the excursions to renewable energy technologies, this book also describes the structural aspects in the establishment of a photovoltaic system.

  4. A comparison of EEG spectral entropy with conventional quantitative ...

    African Journals Online (AJOL)

    A comparison of EEG spectral entropy with conventional quantitative EEG at varying depths of sevoflurane anaesthesia. PR Bartel, FJ Smith, PJ Becker. Abstract. Background and Aim: Recently an electroencephalographic (EEG) spectral entropy module (M-ENTROPY) for an anaesthetic monitor has become commercially ...

  5. Analysis of routine EEG usage in a general adult ICU.

    LENUS (Irish Health Repository)

    McHugh, J C

    2009-09-01

    Non-convulsive seizures and status epilepticus are common in brain-injured patients in intensive care units. Continuous electroencephalography (cEEG) monitoring is the most sensitive means of their detection. In centres where cEEG is unavailable, routine EEG is often utilized for diagnosis although its sensitivity is lower.

  6. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Science.gov (United States)

    2010-04-01

    ... signals by means of radio or telephone transmission systems. (b) Classification. Class II (performance... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electroencephalogram (EEG) telemetry system. 882... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system...

  7. Interictal EEG abnormalities in patients with psychogenic nonepileptic seizures.

    NARCIS (Netherlands)

    Reuber, M.; Fernandez, G.S.E.; Bauer, J.; Singh, D.D.; Elger, C.E.

    2002-01-01

    PURPOSE: To examine interictal EEG abnormalities in patients with psychogenic nonepileptic seizures (PNESs). METHODS: (a) Retrospective study of EEG reports of 187 consecutive patients with PNES seen at the Department of Epileptology, Bonn, Germany; (b) Blinded, multirater comparison of EEGs of all

  8. The colorful brain: Visualization of EEG background patterns

    NARCIS (Netherlands)

    van Putten, Michel Johannes Antonius Maria

    2008-01-01

    This article presents a method to transform routine clinical EEG recordings to an alternative visual domain. The method is intended to support the classic visual interpretation of the EEG background pattern and to facilitate communication about relevant EEG characteristics. In addition, it provides

  9. Fractal Dimension in Epileptic EEG Signal Analysis

    Science.gov (United States)

    Uthayakumar, R.

    Fractal Analysis is the well developed theory in the data analysis of non-linear time series. Especially Fractal Dimension is a powerful mathematical tool for modeling many physical and biological time signals with high complexity and irregularity. Fractal dimension is a suitable tool for analyzing the nonlinear behaviour and state of the many chaotic systems. Particularly in analysis of chaotic time series such as electroencephalograms (EEG), this feature has been used to identify and distinguish specific states of physiological function.Epilepsy is the main fatal neurological disorder in our brain, which is analyzed by the biomedical signal called Electroencephalogram (EEG). The detection of Epileptic seizures in the EEG Signals is an important tool in the diagnosis of epilepsy. So we made an attempt to analyze the EEG in depth for knowing the mystery of human consciousness. EEG has more fluctuations recorded from the human brain due to the spontaneous electrical activity. Hence EEG Signals are represented as Fractal Time Series.The algorithms of fractal dimension methods have weak ability to the estimation of complexity in the irregular graphs. Divider method is widely used to obtain the fractal dimension of curves embedded into a 2-dimensional space. The major problem is choosing initial and final step length of dividers. We propose a new algorithm based on the size measure relationship (SMR) method, quantifying the dimensional behaviour of irregular rectifiable graphs with minimum time complexity. The evidence for the suitability (equality with the nature of dimension) of the algorithm is illustrated graphically.We would like to demonstrate the criterion for the selection of dividers (minimum and maximum value) in the calculation of fractal dimension of the irregular curves with minimum time complexity. For that we design a new method of computing fractal dimension (FD) of biomedical waveforms. Compared to Higuchi's algorithm, advantages of this method include

  10. Electromagnetic source imaging using simultaneous scalp EEG and intracranial EEG: An emerging tool for interacting with pathological brain networks.

    Science.gov (United States)

    Hosseini, Seyed Amir Hossein; Sohrabpour, Abbas; He, Bin

    2018-01-01

    The goal of this study is to investigate the performance, merits and limitations of source imaging using intracranial EEG (iEEG) recordings and to compare its accuracy to the results of EEG source imaging. Accuracy in this study, is measured both by determining the location and inter-nodal connectivity of underlying brain networks. Systematic computer simulation studies are conducted to evaluate iEEG-based source imaging vs. EEG-based source imaging, and source imaging using both EEG and iEEG. To test the source imaging models, networks of inter-connected nodes (in terms of activity) are simulated. The location of the network nodes is randomly selected within a realistic geometry head model and a connectivity link is created among these nodes based on a multi-variate auto-regressive (MVAR) model. Then the forward problem is solved to calculate the potentials at the electrodes and noise (white and correlated) is added to these simulated potentials to simulate realistic measurements. Subsequently, the inverse problem is solved and an algorithm based on principle component analysis is performed on the estimated source activities to determine the location of the simulated network nodes. The activity of these nodes (over time), is then extracted, and used to estimate the connectivity links among the mentioned nodes using Granger causality analysis. Source imaging based on iEEG recordings may or may not improve the accuracy in localization, depending on the number and location of active nodes relative to iEEG electrodes and to other nodes within the network. However, our simulation results suggest that combining EEG and iEEG modalities (simultaneous scalp and intracranial recordings) can improve the imaging accuracy significantly. While iEEG source imaging is useful in estimating the exact location of sources near the iEEG electrodes, combining EEG and iEEG recordings can achieve a more accurate imaging due to the high spatial coverage of the scalp electrodes and the

  11. Interrater variability of EEG interpretation in comatose cardiac arrest patients

    DEFF Research Database (Denmark)

    Westhall, Erik; Rosén, Ingmar; Rossetti, Andrea O

    2015-01-01

    OBJECTIVE: EEG is widely used to predict outcome in comatose cardiac arrest patients, but its value has been limited by lack of a uniform classification. We used the EEG terminology proposed by the American Clinical Neurophysiology Society (ACNS) to assess interrater variability in a cohort.......42) for malignant patterns. Substantial agreement was found for malignant periodic or rhythmic patterns (κ 0.72) while agreement for identifying an unreactive EEG was fair (κ 0.26). CONCLUSIONS: The ACNS EEG terminology can be used to identify highly malignant EEG-patterns in post cardiac arrest patients...

  12. Artifact removal from EEG data with empirical mode decomposition

    Science.gov (United States)

    Grubov, Vadim V.; Runnova, Anastasiya E.; Efremova, Tatyana Yu.; Hramov, Alexander E.

    2017-03-01

    In the paper we propose the novel method for dealing with the physiological artifacts caused by intensive activity of facial and neck muscles and other movements in experimental human EEG recordings. The method is based on analysis of EEG signals with empirical mode decomposition (Hilbert-Huang transform). We introduce the mathematical algorithm of the method with following steps: empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing empirical modes with artifacts, reconstruction of the initial EEG signal. We test the method on filtration of experimental human EEG signals from movement artifacts and show high efficiency of the method.

  13. EEG. Renewables Act. Comment. 4. new rev. and enl. ed.; EEG. Erneuerbare-Energien-Gesetz. Kommentar

    Energy Technology Data Exchange (ETDEWEB)

    Frenz, Walter [RWTH Aachen Univ. (Germany). Lehr- und Forschungsgebiet Berg-, Umwelt- und Europarecht; Mueggenborg, Hans-Juergen [Technische Hochschule Aachen (Germany); Kassel Univ. (Germany); Cosack, Tilman [Hochschule Trier, Umwelt-Campus Birkenfeld (Germany). IREK - Inst. fuer das Recht der Erneuerbaren Energien, Energieeffizienzrecht und Klimaschutzrecht; Ekardt, Felix (ed.) [Forschungsstelle Nachhaltigkeit und Klimapolitik, Leipzig (Germany)

    2015-07-01

    Unlike any other Act, the Renewable Energy Sources Act (EEG) changes continuously. Recently it has been fundamentally transformed with the amendment 2014. Comprehensive, readable and practice-oriented. The proven Berliner comment EEG is your reliable companion through the new regulatory regime. All provisions of the EEG 2014 thorough and easy to understand commented by experts of the matter. 2. The EEG Amending Act of 29.6.2015 has already been considered. A detailed introduction and contributions to the relevant European law and the antitrust aspects of the renewable energy sources to guarantee you a broad understanding of the rules. Valuable background information you provide, the digressions of the most important renewable energy technologies, will explain the pictures thanks to numerous the scientific and technical foundations. Moreover you the construction law aspects in the construction of photovoltaic and wind turbines are explained clearly. [German] Wie kaum ein anderes Gesetz veraendert sich das Erneuerbare-Energien-Gesetz (EEG) laufend. Zuletzt wurde es mit der Novelle 2014 grundlegend umgestaltet. Umfassend, verstaendlich und praxisgerecht Der bewaehrte Berliner Kommentar EEG ist Ihr verlaesslicher Begleiter durch das neue Regelungsregime. Alle Vorschriften des EEG 2014 werden gruendlich und leicht verstaendlich von Kennern der Materie kommentiert. Das 2. EEG-Aenderungsgesetz vom 29.06.2015 ist bereits beruecksichtigt. Eine ausfuehrliche Einleitung sowie Beitraege zum einschlaegigen europaeischen Recht und zu den kartellrechtlichen Aspekten der erneuerbaren Energien verhelfen Ihnen zu einem breiten Verstaendnis der Vorschriften. Wertvolles Hintergrundwissen liefern Ihnen auch die Exkurse zu den wichtigsten Erneuerbare-Energien-Technologien, die Ihnen dank zahlreicher Abbildungen die naturwissenschaftlich-technischen Grundlagen erlaeutern. Zudem werden Ihnen die baurechtlichen Aspekte bei der Errichtung von Photovoltaik- und Windenergieanlagen

  14. EEG source imaging during two Qigong meditations.

    Science.gov (United States)

    Faber, Pascal L; Lehmann, Dietrich; Tei, Shisei; Tsujiuchi, Takuya; Kumano, Hiroaki; Pascual-Marqui, Roberto D; Kochi, Kieko

    2012-08-01

    Experienced Qigong meditators who regularly perform the exercises "Thinking of Nothing" and "Qigong" were studied with multichannel EEG source imaging during their meditations. The intracerebral localization of brain electric activity during the two meditation conditions was compared using sLORETA functional EEG tomography. Differences between conditions were assessed using t statistics (corrected for multiple testing) on the normalized and log-transformed current density values of the sLORETA images. In the EEG alpha-2 frequency, 125 voxels differed significantly; all were more active during "Qigong" than "Thinking of Nothing," forming a single cluster in parietal Brodmann areas 5, 7, 31, and 40, all in the right hemisphere. In the EEG beta-1 frequency, 37 voxels differed significantly; all were more active during "Thinking of Nothing" than "Qigong," forming a single cluster in prefrontal Brodmann areas 6, 8, and 9, all in the left hemisphere. Compared to combined initial-final no-task resting, "Qigong" showed activation in posterior areas whereas "Thinking of Nothing" showed activation in anterior areas. The stronger activity of posterior (right) parietal areas during "Qigong" and anterior (left) prefrontal areas during "Thinking of Nothing" may reflect a predominance of self-reference, attention and input-centered processing in the "Qigong" meditation, and of control-centered processing in the "Thinking of Nothing" meditation.

  15. Illumination influences working memory: an EEG study.

    Science.gov (United States)

    Park, Jin Young; Min, Byoung-Kyong; Jung, Young-Chul; Pak, Hyensou; Jeong, Yeon-Hong; Kim, Eosu

    2013-09-05

    Illumination conditions appear to influence working efficacy in everyday life. In the present study, we obtained electroencephalogram (EEG) correlates of working-memory load, and investigated how these waveforms are modulated by illumination conditions. We hypothesized that illumination conditions may affect cognitive performance. We designed an EEG study to monitor and record participants' EEG during the Sternberg working memory task under four different illumination conditions. Illumination conditions were generated with a factorial design of two color-temperatures (3000 and 7100 K) by two illuminance levels (150 and 700 lx). During a working memory task, we observed that high illuminance led to significantly lower frontal EEG theta activity than did low illuminance. These differences persisted despite no significant difference in task performance between illumination conditions. We found that the latency of an early event-related potential component, such as N1, was significantly modulated by the illumination condition. The fact that the illumination condition affects brain activity but not behavioral performance suggests that the lighting conditions used in the present study did not influence the performance stage of behavioral processing. Nevertheless, our findings provide objective evidence that illumination conditions modulate brain activity. Further studies are necessary to refine the optimal lighting parameters for facilitating working memory. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

  16. Microneedle array electrode for human EEG recording.

    NARCIS (Netherlands)

    Lüttge, Regina; van Nieuwkasteele-Bystrova, Svetlana Nikolajevna; van Putten, Michel Johannes Antonius Maria; Vander Sloten, Jos; Verdonck, Pascal; Nyssen, Marc; Haueisen, Jens

    2009-01-01

    Microneedle array electrodes for EEG significantly reduce the mounting time, particularly by circumvention of the need for skin preparation by scrubbing. We designed a new replication process for numerous types of microneedle arrays. Here, polymer microneedle array electrodes with 64 microneedles,

  17. EEG-based characterization of flicker perception

    NARCIS (Netherlands)

    Lazo, M.; Tsoneva, T.; Garcia Molina, G.

    2013-01-01

    Steady-State Visual Evoked Potential (SSVEP) is an oscillatory electrical response appearing in the electroencephalogram (EEG) in response to flicker stimulation. The SSVEP manifests more prominently in electrodes located near the visual cortex and has oscillatory components at the stimulation

  18. Random matrix analysis of human EEG data

    Czech Academy of Sciences Publication Activity Database

    Šeba, Petr

    2003-01-01

    Roč. 91, - (2003), s. 198104-1 - 198104-4 ISSN 0031-9007 R&D Projects: GA ČR GA202/02/0088 Institutional research plan: CEZ:AV0Z1010914 Keywords : random matrix theory * EEG signal Subject RIV: BE - Theoretical Physics Impact factor: 7.035, year: 2003

  19. Clinical neuropsychiatric correlates and EEG findings among ...

    African Journals Online (AJOL)

    mental retardation.4. This present study focuses on psychomotor developmental delays or disorders; which are divided into specific disorders in which only a ... Nigeria: Lagos University Teaching Hospital (LUTH) and Psychiatric Hospital, Yaba, Lagos. ..... brain imaging could not be done to complement the EEG findings.

  20. Clinical neuropsychiatric correlates and EEG findings among ...

    African Journals Online (AJOL)

    The mean age was 4.8 (±3.9) years, with most subjects falling in the age group of 0-5 years(69.4%). Mixed specific developmental ... proportion had EEG abnormalities of the epileptiform types possibly reinforcing the previously known fact of prevalent subtle brain damage among African children. The need for preventive ...

  1. ORIGINAL ARTICLE EEG changes and neuroimaging abnormalities ...

    African Journals Online (AJOL)

    salah

    Background:Autism is currently viewed as a genetically determined neurode- velopmental disorder although its definite underlying etiology remains to be established. Aim of the Study: Our purpose was to assess autism related morphological neuroimaging changes of the brain and EEG abnormalities in correlation to the.

  2. Correlation between intra- and extracranial background EEG

    DEFF Research Database (Denmark)

    Duun-Henriksen, Jonas; Kjaer, Troels W.; Madsen, Rasmus E.

    2012-01-01

    Scalp EEG is the most widely used modality to record the electrical signals of the brain. It is well known that the volume conduction of these brain waves through the brain, cerebrospinal fluid, skull and scalp reduces the spatial resolution and the signal amplitude. So far the volume conduction...

  3. EEG Power During Waking and NREM Sleep in Primary Insomnia

    Science.gov (United States)

    Wu, You Meme; Pietrone, Regina; Cashmere, J. David; Begley, Amy; Miewald, Jean M.; Germain, Anne; Buysse, Daniel J.

    2013-01-01

    Objective: Pathophysiological models of insomnia invoke the concept of 24-hour hyperarousal, which could lead to symptoms and physiological findings during waking and sleep. We hypothesized that this arousal could be seen in the waking electroencephalogram (EEG) of individuals with primary insomnia (PI), and that waking EEG power would correlate with non-REM (NREM) EEG. Methods: Subjects included 50 PI and 32 good sleeper controls (GSC). Five minutes of eyes closed waking EEG were collected at subjects' usual bedtimes, followed by polysomnography (PSG) at habitual sleep times. An automated algorithm and visual editing were used to remove artifacts from waking and sleep EEGs, followed by power spectral analysis to estimate power from 0.5–32 Hz. Results: We did not find significant differences in waking or NREM EEG spectral power of PI and GSC. Significant correlations between waking and NREM sleep power were observed across all frequency bands in the PI group and in most frequency bands in the GSC group. Conclusions: The absence of significant differences between groups in waking or NREM EEG power suggests that our sample was not characterized by a high degree of cortical arousal. The consistent correlations between waking and NREM EEG power suggest that, in samples with elevated NREM EEG beta activity, waking EEG power may show a similar pattern. Citation: Wu YM; Pietrone R; Cashmere JD; Begley A; Miewald JM; Germain A; Buysse DJ. EEG power during waking and NREM sleep in primary insomnia. J Clin Sleep Med 2013;9(10):1031-1037. PMID:24127147

  4. A physiology-based seizure detection system for multichannel EEG.

    Directory of Open Access Journals (Sweden)

    Chia-Ping Shen

    Full Text Available BACKGROUND: Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. Electroencephalogram (EEG signals play a critical role in the diagnosis of epilepsy. Multichannel EEGs contain more information than do single-channel EEGs. Automatic detection algorithms for spikes or seizures have traditionally been implemented on single-channel EEG, and algorithms for multichannel EEG are unavailable. METHODOLOGY: This study proposes a physiology-based detection system for epileptic seizures that uses multichannel EEG signals. The proposed technique was tested on two EEG data sets acquired from 18 patients. Both unipolar and bipolar EEG signals were analyzed. We employed sample entropy (SampEn, statistical values, and concepts used in clinical neurophysiology (e.g., phase reversals and potential fields of a bipolar EEG to extract the features. We further tested the performance of a genetic algorithm cascaded with a support vector machine and post-classification spike matching. PRINCIPAL FINDINGS: We obtained 86.69% spike detection and 99.77% seizure detection for Data Set I. The detection system was further validated using the model trained by Data Set I on Data Set II. The system again showed high performance, with 91.18% detection of spikes and 99.22% seizure detection. CONCLUSION: We report a de novo EEG classification system for seizure and spike detection on multichannel EEG that includes physiology-based knowledge to enhance the performance of this type of system.

  5. Relation of EEG and computerized tomography in transient ischaemic attacks

    International Nuclear Information System (INIS)

    Ladurner, G.; Enge, S.; Sager, W.D.; Logar, C.; Lechner, H.; Landeskrankenhaus Graz; Graz Univ.

    1981-01-01

    80 patients with transient ischaemic attack (TIA) were examined via computer tomogram (CT) and electronencephalogram (EEG). 53 patients were found to have a normal CT and 32 a normal EEG. In the patients with pathological CT findings (27) a significantly lower number of normal EEG's (22) was seen. Further subdivision of the 27 pathological CT findings revealed 12 patients with hypodense areas (infarctions) and 15 patients with an atrophy only. A normal EEG was significantly rarer in patients with a hypodense lesion (2) and in those with atrophy (3), focal EEG changes being significantly more frequent. Hence EEG findings facilitate the aetiological linking of an atrophy to an ischaemic stroke, especially when EEG follow-up examinations are included in the diagnostic procedure. (orig.) [de

  6. EEG Based Inference of Spatio-Temporal Brain Dynamics

    DEFF Research Database (Denmark)

    Hansen, Sofie Therese

    Electroencephalography (EEG) provides a measure of brain activity and has improved our understanding of the brain immensely. However, there is still much to be learned and the full potential of EEG is yet to be realized. In this thesis we suggest to improve the information gain of EEG using three....... The main topic of this thesis is the localization of the EEG generators. This entails solving both a forward and an inverse problem. The inverse problem maps the EEG signal recorded on the scalp to its origin in the brain. It is a highly ill-posed problem which we tackle by employing a sparsity promoting...... recovery ability. The forward problem describes the propagation of neuronal activity in the brain to the EEG electrodes on the scalp. The geometry and conductivity of the head layers are normally required to model this path. We propose a framework for inferring forward models which is based on the EEG...

  7. EEG microstates of wakefulness and NREM sleep.

    Science.gov (United States)

    Brodbeck, Verena; Kuhn, Alena; von Wegner, Frederic; Morzelewski, Astrid; Tagliazucchi, Enzo; Borisov, Sergey; Michel, Christoph M; Laufs, Helmut

    2012-09-01

    EEG-microstates exploit spatio-temporal EEG features to characterize the spontaneous EEG as a sequence of a finite number of quasi-stable scalp potential field maps. So far, EEG-microstates have been studied mainly in wakeful rest and are thought to correspond to functionally relevant brain-states. Four typical microstate maps have been identified and labeled arbitrarily with the letters A, B, C and D. We addressed the question whether EEG-microstate features are altered in different stages of NREM sleep compared to wakefulness. 32-channel EEG of 32 subjects in relaxed wakefulness and NREM sleep was analyzed using a clustering algorithm, identifying the most dominant amplitude topography maps typical of each vigilance state. Fitting back these maps into the sleep-scored EEG resulted in a temporal sequence of maps for each sleep stage. All 32 subjects reached sleep stage N2, 19 also N3, for at least 1 min and 45 s. As in wakeful rest we found four microstate maps to be optimal in all NREM sleep stages. The wake maps were highly similar to those described in the literature for wakefulness. The sleep stage specific map topographies of N1 and N3 sleep showed a variable but overall relatively high degree of spatial correlation to the wake maps (Mean: N1 92%; N3 87%). The N2 maps were the least similar to wake (mean: 83%). Mean duration, total time covered, global explained variance and transition probabilities per subject, map and sleep stage were very similar in wake and N1. In wake, N1 and N3, microstate map C was most dominant w.r.t. global explained variance and temporal presence (ratio total time), whereas in N2 microstate map B was most prominent. In N3, the mean duration of all microstate maps increased significantly, expressed also as an increase in transition probabilities of all maps to themselves in N3. This duration increase was partly--but not entirely--explained by the occurrence of slow waves in the EEG. The persistence of exactly four main microstate

  8. Frequency of EEG abnormalities in age-matched siblings of autistic children with abnormal sleep EEG patterns.

    Science.gov (United States)

    Chez, Michael G; Buchanan, Thomas; Aimonovitch, Mary; Mrazek, Susan; Krasne, Valerie; Langburt, Wayne; Memon, Shoaib

    2004-04-01

    Epileptiform activity in sleep has been described even in the absence of clinical seizures in 43-68% of patients with autistic spectrum disorders (ASDs). Genetic factors may play a significant role in the frequency of epilepsy, yet the frequency in normal age-matched controls is unknown. We studied overnight ambulatory electroencephalograms (EEGs) in 12 nonepileptic, nonautistic children with a sibling with both ASDs and an abnormal EEG. EEG studies were read and described independently by two pediatric epileptologists; 10 were normal studies and 2 were abnormal. The occurrence of abnormal EEGs in our sample (16.6%) was lower than the reported occurrence in children with ASDs. Further, the two abnormal EEGs were of types typically found in childhood and were different from those found in the ASD-affected siblings. The lack of similarity between sibling EEGs suggests that genetic factors alone do not explain the higher frequency of EEG abnormalities reported in ASDs.

  9. Causality within the epileptic network: an EEG-fMRI study validated by intracranial EEG.

    Directory of Open Access Journals (Sweden)

    Anna Elisabetta eVaudano

    2013-11-01

    Full Text Available Accurate localization of the Seizure Onset Zone (SOZ is crucial in patients with drug-resistance focal epilepsy. EEG with fMRI recording (EEG-fMRI has been proposed as a complementary non-invasive tool, which can give useful additional information in the pre-surgical workup. However, fMRI maps related to interictal epileptiform activities (IED often show multiple regions of signal change, or networks, rather than highly focal ones. Effective connectivity approaches like Dynamic Causal Modelling (DCM applied to fMRI data potentially offers a framework to address which brain regions drives the generation of seizures and IED within an epileptic network. Here we present a first attempt to validate DCM on EEG-fMRI data in one patient affected by frontal lobe epilepsy. Pre-surgical EEG-fMRI demonstrated two distinct clusters of BOLD signal increases linked to IED, one located in the left frontal pole and the other in the ipsilateral dorso-lateral frontal cortex. DCM of the IED-related BOLD signal favoured a model corresponding to the left dorsolateral frontal cortex as driver of changes in the fronto-polar region. The validity of DCM was supported by: (a the results of two different non-invasive analysis obtained on the same dataset: EEG source imaging (ESI, and psychophysiological interaction analysis (PPI; (b the failure of a first surgical intervention limited to the fronto-polar region; (c the results of the intracranial EEG monitoring performed after the first surgical intervention confirming a SOZ located over the dorso-lateral frontal cortex. These results add evidence that EEG-fMRI together with advanced methods of BOLD signal analysis is a promising tool that can give relevant information within the epilepsy surgery diagnostic work-up.

  10. Screening EEG in Aircrew Selection: Clinical Aerospace Neurology Perspective

    Science.gov (United States)

    Clark, Jonathan B.; Riley, Terrence

    2001-01-01

    As clinical aerospace neurologists we do not favor using screening EEG in pilot selection on unselected and otherwise asymptomatic individuals. The role of EEG in aviation screening should be as an adjunct to diagnosis, and the decision to disqualify a pilot should never be based solely on the EEG. Although a policy of using a screening EEG in an unselected population might detect an individual with a potentially increased relative risk, it would needlessly exclude many applicants who would probably never have a seizure. A diagnostic test performed on an asymptomatic individual without clinical indications, in a population with a low prevalence of disease (seizure) may be of limited or possibly detrimental value. We feel that rather than do EEGs on all candidates, a better approach would be to perform an EEG for a specific indication, such as family history of seizure, single convulsion (seizure) , history of unexplained loss of consciousness or head injury. Routine screening EEGs in unselected aviation applications are not done without clinical indication in the U.S. Air Force, Navy, or NASA. The USAF discontinued routine screening EEGs for selection in 1978, the U.S. Navy discontinued it in 1981 , and NASA discontinued it in 1995. EEG as an aeromedical screening tool in the US Navy dates back to 1939. The US Navy routinely used EEGs to screen all aeromedical personnel from 1961 to 1981. The incidence of epileptiform activity on EEG in asymptomatic flight candidates ranges from 0.11 to 2.5%. In 3 studies of asymptomatic flight candidates with epileptiform activity on EEG followed for 2 to 15 years, 1 of 31 (3.2%), 1 of 30 (3.3%), and 0 of 14 (0%) developed a seizure, for a cumulative risk of an individual with an epileptiform EEG developing a seizure of 2.67% (2 in 75). Of 28,658 student naval aviation personnel screened 31 had spikes and/or slow waves on EEG, and only 1 later developed a seizure. Of the 28,627 who had a normal EEG, 4 later developed seizures, or

  11. The role of the standard EEG in clinical psychiatry.

    LENUS (Irish Health Repository)

    O'Sullivan, S S

    2012-02-03

    BACKGROUND: The EEG is a commonly requested test on patients attending psychiatric services, predominantly to investigate for a possible organic brain syndrome causing behavioural changes. AIMS: To assess referrals for EEG from psychiatric services in comparison with those from other sources. We determine which clinical factors were associated with an abnormal EEG in patients referred from psychiatric sources. METHODS: A retrospective review of EEG requests in a 1-year period was performed. Analysis of referral reasons for psychiatric patients was undertaken, and outcome of patients referred from psychiatric services post-EEG was reviewed. RESULTS: One thousand four hundred and seventy EEGs were reviewed, of which 91 (6.2%) were referred from psychiatry. Neurology service referrals had detection rates of abnormal EEGs of 27%, with psychiatric referrals having the lowest abnormality detection rate of 17.6% (p < 0.1). In psychiatric-referred patients the only significant predictors found of an abnormal EEG were a known history of epilepsy (p < 0.001), being on clozapine (p < 0.05), and a possible convulsive seizure (RR = 6.51). Follow-up data of 53 patients did not reveal a significant clinical impact of EEG results on patient management. CONCLUSIONS: Many patients are referred for EEG from psychiatric sources despite a relatively low index of suspicion of an organic brain disorders, based on reasons for referral documented, with an unsurprising low clinical yield.

  12. Donepezil Impairs Memory in Healthy Older Subjects: Behavioural, EEG and Simultaneous EEG/fMRI Biomarkers

    Science.gov (United States)

    Balsters, Joshua H.; O'Connell, Redmond G.; Martin, Mary P.; Galli, Alessandra; Cassidy, Sarah M.; Kilcullen, Sophia M.; Delmonte, Sonja; Brennan, Sabina; Meaney, Jim F.; Fagan, Andrew J.; Bokde, Arun L. W.; Upton, Neil; Lai, Robert; Laruelle, Marc; Lawlor, Brian; Robertson, Ian H.

    2011-01-01

    Rising life expectancies coupled with an increasing awareness of age-related cognitive decline have led to the unwarranted use of psychopharmaceuticals, including acetylcholinesterase inhibitors (AChEIs), by significant numbers of healthy older individuals. This trend has developed despite very limited data regarding the effectiveness of such drugs on non-clinical groups and recent work indicates that AChEIs can have negative cognitive effects in healthy populations. For the first time, we use a combination of EEG and simultaneous EEG/fMRI to examine the effects of a commonly prescribed AChEI (donepezil) on cognition in healthy older participants. The short- and long-term impact of donepezil was assessed using two double-blind, placebo-controlled trials. In both cases, we utilised cognitive (paired associates learning (CPAL)) and electrophysiological measures (resting EEG power) that have demonstrated high-sensitivity to age-related cognitive decline. Experiment 1 tested the effects of 5 mg/per day dosage on cognitive and EEG markers at 6-hour, 2-week and 4-week follow-ups. In experiment 2, the same markers were further scrutinised using simultaneous EEG/fMRI after a single 5 mg dose. Experiment 1 found significant negative effects of donepezil on CPAL and resting Alpha and Beta band power. Experiment 2 replicated these results and found additional drug-related increases in the Delta band. EEG/fMRI analyses revealed that these oscillatory differences were associated with activity differences in the left hippocampus (Delta), right frontal-parietal network (Alpha), and default-mode network (Beta). We demonstrate the utility of simple cognitive and EEG measures in evaluating drug responses after acute and chronic donepezil administration. The presentation of previously established markers of age-related cognitive decline indicates that AChEIs can impair cognitive function in healthy older individuals. To our knowledge this is the first study to identify the precise

  13. Emotional responses as independent components in EEG

    DEFF Research Database (Denmark)

    Jensen, Camilla Birgitte Falk; Petersen, Michael Kai; Larsen, Jakob Eg

    2014-01-01

    Combine wireless neuroheadsets with smartphones that enable mobile brain imaging can potentially allow us to design cognitive interfaces which adapt to our affective responses. Neuroimaging experiments using electroencephalography (EEG) initially identified two components elicited by pleasant...... or unpleasant images; early posterior negativity (EPN) and late positive potential (LPP). Recent studies suggest that several time course components may be modulated by emotional content in images or text. However these neural signatures are characterized by small voltage changes that would be highly...... susceptible to noise if captured in a mobile context. Hypothesizing that retrieval of emotional responses in mobile usage scenarios could be enhanced through spatial filtering, we compare a standard EEG electrode based analysis against an approach based on independent component analysis (ICA). By clustering...

  14. Functional Mapping with Simultaneous MEG and EEG

    OpenAIRE

    Liu, Hesheng; Tanaka, Naoaki; Stufflebeam, Steven; Ahlfors, Seppo; Hämäläinen, Matti

    2010-01-01

    We use magnetoencephalography (MEG) and electroencephalography (EEG) to locate and determine the temporal evolution in brain areas involved in the processing of simple sensory stimuli. We will use somatosensory stimuli to locate the hand somatosensory areas, auditory stimuli to locate the auditory cortices, visual stimuli in four quadrants of the visual field to locate the early visual areas. These type of experiments are used for functional mapping in epileptic and brain tumor patients to lo...

  15. EEG microstates during resting represent personality differences

    OpenAIRE

    Schlegel, Felix; Lehmann, Dietrich; Faber, Pascal L.; Milz, Patricia; Gianotti, Lorena R. R.

    2011-01-01

    We investigated the spontaneous brain electric activity of 13 skeptics and 16 believers in paranormal phenomena; they were university students assessed with a self-report scale about paranormal beliefs. 33-channel EEG recordings during no-task resting were processed as sequences of momentary potential distribution maps. Based on the maps at peak times of Global Field Power, the sequences were parsed into segments of quasi-stable potential distribution, the 'microstates'. The microstates were ...

  16. Statistical maps for EEG dipolar source localization.

    Science.gov (United States)

    Bénar, Christian G; Gunn, Roger N; Grova, Christophe; Champagne, Benoît; Gotman, Jean

    2005-03-01

    We present a method that estimates three-dimensional statistical maps for electroencephalogram (EEG) source localization. The maps assess the likelihood that a point in the brain contains a dipolar source, under the hypothesis of one, two or three activated sources. This is achieved by examining all combinations of one to three dipoles on a coarse grid and attributing to each combination a score based on an F statistic. The probability density function of the statistic under the null hypothesis is estimated nonparametrically, using bootstrap resampling. A theoretical F distribution is then fitted to the empirical distribution in order to allow correction for multiple comparisons. The maps allow for the systematic exploration of the solution space for dipolar sources. They permit to test whether the data support a given solution. They do not rely on the assumption of uncorrelated source time courses. They can be compared to other statistical parametric maps such as those used in functional magnetic resonance imaging (fMRI). Results are presented for both simulated and real data. The maps were compared with LORETA and MUSIC results. For the real data consisting of an average of epileptic spikes, we observed good agreement between the EEG statistical maps, intracranial EEG recordings, and fMRI activations.

  17. Evaluation of postoperative sharp waveforms through EEG and magnetoencephalography.

    Science.gov (United States)

    Lee, Jong Woo; Tanaka, Naoaki; Shiraishi, Hideaki; Milligan, Tracey A; Dworetzky, Barbara A; Khoshbin, Shahram; Stufflebeam, Steven M; Bromfield, Edward B

    2010-02-01

    EEGs obtained after craniotomy are difficult to read because of a breach rhythm consisting of unfiltered sharply contoured physiologic waveforms that can mimic interictal epileptiform discharges. Magnetoencephalography (MEG) is less affected by the skull breach. The postcraniotomy EEG and MEG scans of 20 patients were reviewed by two experienced electroencephalographers. Larger interrater variability was found for EEG as compared with MEG. Review of patients who had postoperative seizures suggested that EEG was more sensitive but less specific than MEG in detecting interictal epileptiform discharges. Furthermore, several instances of sharp waveforms that were difficult to evaluate on EEG were found to be more easily interpretable on MEG. MEG may also help determine whether asymmetries in physiologic rhythms on EEG result from the skull defect or are pathologic. MEG should be considered as an adjunctive study in patients with a breach rhythm for evaluation of interictal epileptiform discharges and cerebral dysfunction.

  18. Memories of attachment hamper EEG cortical connectivity in dissociative patients.

    Science.gov (United States)

    Farina, Benedetto; Speranza, Anna Maria; Dittoni, Serena; Gnoni, Valentina; Trentini, Cristina; Vergano, Carola Maggiora; Liotti, Giovanni; Brunetti, Riccardo; Testani, Elisa; Della Marca, Giacomo

    2014-08-01

    In this study, we evaluated cortical connectivity modifications by electroencephalography (EEG) lagged coherence analysis, in subjects with dissociative disorders and in controls, after retrieval of attachment memories. We asked thirteen patients with dissociative disorders and thirteen age- and sex-matched healthy controls to retrieve personal attachment-related autobiographical memories through adult attachment interviews (AAI). EEG was recorded in the closed eyes resting state before and after the AAI. EEG lagged coherence before and after AAI was compared in all subjects. In the control group, memories of attachment promoted a widespread increase in EEG connectivity, in particular in the high-frequency EEG bands. Compared to controls, dissociative patients did not show an increase in EEG connectivity after the AAI. Conclusions: These results shed light on the neurophysiology of the disintegrative effect of retrieval of traumatic attachment memories in dissociative patients.

  19. The choice of the source space and the Laplacian matrix in LORETA and the spatio-temporal Kalman filter EEG inverse methods.

    Science.gov (United States)

    Habboush, Nawar; Hamid, Laith; Japaridze, Natia; Wiegand, Gert; Heute, Ulrich; Stephani, Ulrich; Galka, Andreas; Siniatchkin, Michael

    2015-08-01

    The discretization of the brain and the definition of the Laplacian matrix influence the results of methods based on spatial and spatio-temporal smoothness, since the Laplacian operator is used to define the smoothness based on the neighborhood of each grid point. In this paper, the results of low resolution electromagnetic tomography (LORETA) and the spatiotemporal Kalman filter (STKF) are computed using, first, a greymatter source space with the standard definition of the Laplacian matrix and, second, using a whole-brain source space and a modified definition of the Laplacian matrix. Electroencephalographic (EEG) source imaging results of five inter-ictal spikes from a pre-surgical patient with epilepsy are used to validate the two aforementioned approaches. The results using the whole-brain source space and the modified definition of the Laplacian matrix were concentrated in a single source activation, stable, and concordant with the location of the focal cortical dysplasia (FCD) in the patient's brain compared with the results which use a grey-matter grid and the classical definition of the Laplacian matrix. This proof-of-concept study demonstrates a substantial improvement of source localization with both LORETA and STKF and constitutes a basis for further research in a large population of patients with epilepsy.

  20. Exploring EEG signals in a Brain-Computer Interface

    Science.gov (United States)

    Zubrycki, Paweł; Mulawka, Jan

    2014-11-01

    This article shows the basic methods of electroencephalography EEG signal exploration. It contains information about data acquisition and different methods in which brain-computer interfaces can be made. The main focus of the paper is to find a way to determine the best set of parameters to detect movement of a hand in EEG signal. In the introduction there is also short introduction to EEG as well as fundamentals of support vector machine.

  1. Burst suppression in sleep in a routine outpatient EEG

    Directory of Open Access Journals (Sweden)

    Ammar Kheder

    2014-01-01

    Full Text Available Burst suppression (BS is an electroencephalogram (EEG pattern that is characterized by brief bursts of spikes, sharp waves, or slow waves of relatively high amplitude alternating with periods of relatively flat EEG or isoelectric periods. The pattern is usually associated with coma, severe encephalopathy of various etiologies, or general anesthesia. We describe an unusual case of anoxic brain injury in which a BS pattern was seen during behaviorally defined sleep during a routine outpatient EEG study.

  2. Neural decoding of expressive human movement from scalp electroencephalography (EEG)

    OpenAIRE

    Zachery Ryan Hernandez; Zachery Ryan Hernandez; Jesus Gabriel Cruz-Garza; Jesus Gabriel Cruz-Garza; Sargoon eNepaul; Karen Kohn Bradley; Jose Luis Contreras-Vidal; Jose Luis Contreras-Vidal

    2014-01-01

    Although efforts to characterize human movement through EEG have revealed neural activities unique to limb control that can be used to infer movement kinematics, it is still unknown the extent to which EEG can be used to discern the expressive qualities that influence such movements. In this study we used EEG and inertial sensors to record brain activity and movement of five skilled and certified Laban Movement Analysis (LMA) dancers. Each dancer performed whole body functional movements of t...

  3. [Interaction of diazepam and levodropropizine evaluated with quantitative EEG].

    Science.gov (United States)

    Arrigo, A; Bejor, M; Beungarbe, D; Cosentina, R

    1989-02-01

    The purpose of this clinical trial was to evaluate the presence of possible interactions between Levodropropizine and benzodiazepines (BZ). Experience was performed recording bioccipital quantified EEG in 5 healthy volunteers in normal conditions, after BZ administration and after BZ plus Levodropropizine administration. The slight shifting towards lower frequences in quantified EEG, due to BZ, was not modified by Levodropropizine administration. As results from this experience Levodropropizine seems not to have sinergic action on BZ effect in quantified EEG.

  4. Age-related effects in the EEG during propofol anaesthesia.

    Science.gov (United States)

    Schultz, A; Grouven, U; Zander, I; Beger, F A; Siedenberg, M; Schultz, B

    2004-01-01

    Age-related differences in the spectral composition of the EEG in induction and emergence times, and in drug consumption during propofol anaesthesia were investigated. The EEGs of 60 female patients between 22 and 85 years of age were monitored continuously during standardized induction of anaesthesia with 2 mg of propofol kg(-1)60 s(-1). The EEGs were visually assessed in 20-s epochs according to a scale from A (awake) to F (very deep hypnosis). Visual EEG classifications, spectral parameters, and induction times were compared between different age groups. Additionally, data of 546 patients included in a multicentre study with 4630 patients (EEG monitor Narcotrend, MT MonitorTechnik, Bad Bramstedt, Germany) were analyzed with regard to age-dependent changes of propofol consumption using target-controlled infusion (TCI). During induction, patients older than 70 years reached significantly deeper EEG stages than younger patients, needed a longer time to reach the deepest EEG stage, and needed more time until a light EEG stage was regained. In patients aged 70 years and older, the total power, mainly in deep EEG stages, was significantly smaller due to a distinctly smaller absolute power of the delta frequency band. No single spectral parameter was able to reliably distinguish all EEG stages. During the steady state of anaesthesia, older patients needed less propofol for the maintenance of a defined stage of hypnosis than younger patients. Older patients differ from younger ones regarding the hypnotic effect of propofol and the spectral patterns in the EEG. For an efficient automatic assessment of the EEG during anaesthesia a multivariable approach accounting for age-effects is indispensable.

  5. Deep Neural Architectures for Mapping Scalp to Intracranial EEG.

    Science.gov (United States)

    Antoniades, Andreas; Spyrou, Loukianos; Martin-Lopez, David; Valentin, Antonio; Alarcon, Gonzalo; Sanei, Saeid; Took, Clive Cheong

    2018-03-19

    Data is often plagued by noise which encumbers machine learning of clinically useful biomarkers and electroencephalogram (EEG) data is no exemption. Intracranial EEG (iEEG) data enhances the training of deep learning models of the human brain, yet is often prohibitive due to the invasive recording process. A more convenient alternative is to record brain activity using scalp electrodes. However, the inherent noise associated with scalp EEG data often impedes the learning process of neural models, achieving substandard performance. Here, an ensemble deep learning architecture for nonlinearly mapping scalp to iEEG data is proposed. The proposed architecture exploits the information from a limited number of joint scalp-intracranial recording to establish a novel methodology for detecting the epileptic discharges from the sEEG of a general population of subjects. Statistical tests and qualitative analysis have revealed that the generated pseudo-intracranial data are highly correlated with the true intracranial data. This facilitated the detection of IEDs from the scalp recordings where such waveforms are not often visible. As a real-world clinical application, these pseudo-iEEGs are then used by a convolutional neural network for the automated classification of intracranial epileptic discharges (IEDs) and non-IED of trials in the context of epilepsy analysis. Although the aim of this work was to circumvent the unavailability of iEEG and the limitations of sEEG, we have achieved a classification accuracy of 68% an increase of 6% over the previously proposed linear regression mapping.

  6. Adaptive frequency decomposition of EEG with subsequent expert system analysis.

    Science.gov (United States)

    Herrmann, C S; Arnold, T; Visbeck, A; Hundemer, H P; Hopf, H C

    2001-11-01

    We present a hybrid system for automatic analysis of clinical routine EEG, comprising a spectral analysis and an expert system. EEG raw data are transformed into the time-frequency domain by the so-called adaptive frequency decomposition. The resulting frequency components are converted into pseudo-linguistic facts via fuzzification. Finally, an expert system applies symbolic rules formulated by the neurologist to evaluate the extracted EEG features. The system detects artefacts, describes alpha rhythm by frequency, amplitude, and stability and after artefact rejection detects pathologic slow activity. All results are displayed as linguistic terms, numerical values and maps of temporal extent, giving an overview about the clinical routine EEG.

  7. Synchronization of EEG activity in patients with bipolar disorder

    International Nuclear Information System (INIS)

    Panischev, O Yu; Demin, S A; Muhametshin, I G; Yu Demina, N

    2015-01-01

    In paper we apply the method based on the Flicker-Noise Spectroscopy (FNS) to determine the differences in frequency-phase synchronization of the cortical electroencephalographic (EEG) activities in patients with bipolar disorder (BD). We found that for healthy subjects the frequency-phase synchronization of EEGs from long-range electrodes was significantly better for BD patients. In BD patients a high synchronization of EEGs was observed only for short-range electrodes. Thus, the FNS is a simple graphical method for qualitative analysis can be applied to identify the synchronization effects in EEG activity and, probably, may be used for the diagnosis of this syndrome. (paper)

  8. Synchronization of EEG activity in patients with bipolar disorder

    Science.gov (United States)

    Panischev, O. Yu; Demin, S. A.; Muhametshin, I. G.; Demina, N. Yu

    2015-12-01

    In paper we apply the method based on the Flicker-Noise Spectroscopy (FNS) to determine the differences in frequency-phase synchronization of the cortical electroencephalographic (EEG) activities in patients with bipolar disorder (BD). We found that for healthy subjects the frequency-phase synchronization of EEGs from long-range electrodes was significantly better for BD patients. In BD patients a high synchronization of EEGs was observed only for short-range electrodes. Thus, the FNS is a simple graphical method for qualitative analysis can be applied to identify the synchronization effects in EEG activity and, probably, may be used for the diagnosis of this syndrome.

  9. Standardized computer-based organized reporting of EEG:SCORE

    DEFF Research Database (Denmark)

    Beniczky, Sandor; H, Aurlien,; JC, Brøgger,

    2013-01-01

    in free-text format. The purpose of our endeavor was to create a computer-based system for EEG assessment and reporting, where the physicians would construct the reports by choosing from predefined elements for each relevant EEG feature, as well as the clinical phenomena (for video-EEG recordings....... SCORE can potentially improve the quality of EEG assessment and reporting; it will help incorporate the results of computer-assisted analysis into the report, it will make possible the build-up of a multinational database, and it will help in training young neurophysiologists....

  10. Association of patients with parkinsonism and epilepsy with EEG changes.

    Science.gov (United States)

    Petrov, Igor

    2006-07-01

    EEG is an important diagnostic method for epilepsies. EEG changes in patients with Parkinson's disease and epilepsy are not unknown or unexpected events. We investigated 250 Parkinson's disease patients. Epileptic seizures were recorded in 10 patients. Four patients had generalized tonic clonic seizures; 3 partial complex seizures, 2 of which with secondary generalization; while 3 patients had right-handed simple motor partial seizure. Clinical and neurophysiological investigations, neuroimagining techniques electroencephalographic investigations (EEG, EEG in sleep) were conducted. Our patients were well controlled with antiepileptic therapy.

  11. The clinical use of quantitative EEG in cognitive disorders

    Directory of Open Access Journals (Sweden)

    Paulo Afonso de Medeiros Kanda

    Full Text Available Abstract The primary diagnosis of most cognitive disorders is clinically based, but the EEG plays a role in evaluating, classifying and following some of these disorders. There is an ongoing debate over routine use of qEEG. Although many findings regarding the clinical use of quantitative EEG are awaiting validation by independent investigators while confirmatory clinical follow-up studies are also needed, qEEG can be cautiously used by a skilled neurophysiologist in cognitive dysfunctions to improve the analysis of background activity, slow/fast focal activity, subtle asymmetries, spikes and waves, as well as in longitudinal follow-ups.

  12. Altered resting state EEG in chronic pancreatitis patients: toward a marker for chronic pain

    NARCIS (Netherlands)

    Vries, M. de; Wilder-Smith, O.H.G.; Jongsma, M.L.A.; Broeke, E.N. van den; Arns, M.W.; Goor, H. van; Rijn, C.M. van

    2013-01-01

    OBJECTIVES: Electroencephalography (EEG) may be a promising source of physiological biomarkers accompanying chronic pain. Several studies in patients with chronic neuropathic pain have reported alterations in central pain processing, manifested as slowed EEG rhythmicity and increased EEG power in

  13. Online Reduction of Artifacts in EEG of Simultaneous EEG-fMRI Using Reference Layer Adaptive Filtering (RLAF).

    Science.gov (United States)

    Steyrl, David; Krausz, Gunther; Koschutnig, Karl; Edlinger, Günter; Müller-Putz, Gernot R

    2018-01-01

    Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) allow us to study the active human brain from two perspectives concurrently. Signal processing based artifact reduction techniques are mandatory for this, however, to obtain reasonable EEG quality in simultaneous EEG-fMRI. Current artifact reduction techniques like average artifact subtraction (AAS), typically become less effective when artifact reduction has to be performed on-the-fly. We thus present and evaluate a new technique to improve EEG quality online. This technique adds up with online AAS and combines a prototype EEG-cap for reference recordings of artifacts, with online adaptive filtering and is named reference layer adaptive filtering (RLAF). We found online AAS + RLAF to be highly effective in improving EEG quality. Online AAS + RLAF outperformed online AAS and did so in particular online in terms of the chosen performance metrics, these being specifically alpha rhythm amplitude ratio between closed and opened eyes (3-45% improvement), signal-to-noise-ratio of visual evoked potentials (VEP) (25-63% improvement), and VEPs variability (16-44% improvement). Further, we found that EEG quality after online AAS + RLAF is occasionally even comparable with the offline variant of AAS at a 3T MRI scanner. In conclusion RLAF is a very effective add-on tool to enable high quality EEG in simultaneous EEG-fMRI experiments, even when online artifact reduction is necessary.

  14. Topographic time-frequency decomposition of the EEG.

    Science.gov (United States)

    Koenig, T; Marti-Lopez, F; Valdes-Sosa, P

    2001-08-01

    Frequency-transformed EEG resting data has been widely used to describe normal and abnormal brain functional states as function of the spectral power in different frequency bands. This has yielded a series of clinically relevant findings. However, by transforming the EEG into the frequency domain, the initially excellent time resolution of time-domain EEG is lost. The topographic time-frequency decomposition is a novel computerized EEG analysis method that combines previously available techniques from time-domain spatial EEG analysis and time-frequency decomposition of single-channel time series. It yields a new, physiologically and statistically plausible topographic time-frequency representation of human multichannel EEG. The original EEG is accounted by the coefficients of a large set of user defined EEG like time-series, which are optimized for maximal spatial smoothness and minimal norm. These coefficients are then reduced to a small number of model scalp field configurations, which vary in intensity as a function of time and frequency. The result is thus a small number of EEG field configurations, each with a corresponding time-frequency (Wigner) plot. The method has several advantages: It does not assume that the data is composed of orthogonal elements, it does not assume stationarity, it produces topographical maps and it allows to include user-defined, specific EEG elements, such as spike and wave patterns. After a formal introduction of the method, several examples are given, which include artificial data and multichannel EEG during different physiological and pathological conditions. Copyright 2001 Academic Press.

  15. Hippocampal EEG and behaviour in dog. I. Hippocampal EEG correlates of gross motor behaviour

    NARCIS (Netherlands)

    Arnolds, D.E.A.T.; Lopes da Silva, F.H.; Aitink, J.W.; Kamp, A.

    It was shown that rewarding spectral shifts (i.e. increase in amplitude or peak frequency of the hippocampal EEG) causes a solitary dog to show increased motor behaviour. Rewarded spectral shifts concurred with a variety of behavioural transitions. It was found that statistically significant

  16. Emergency EEG: study of survival EEG de urgência: taxa de sobrevivência

    Directory of Open Access Journals (Sweden)

    Moacir Alves Borges

    2010-04-01

    Full Text Available OBJECTIVE: To determine the survival rate according to the main findings of emergency electroencephalography (EEGs of patients treated in a tertiary hospital. METHOD: In this prospective study, the findings of consecutive emergency EEGs performed on inpatients in Hospital de Base in São José do Rio Preto, Brazil were correlated with survival utilizing Kaplan-Meyer survival curves. RESULTS: A total of 681 patients with an average age of 42 years old (1 day to 96 years were evaluated, of which 406 were male. The main reasons for EEGs were epileptic seizures (221 cases, hepatic encephalopathy [116 cases of which 85 (73.3% were men, p-value=0.001], status epilepticus (104 cases and impaired consciousness (78 cases. The underlying disease was confirmed in 578 (84.3% cases with 119 (17.5% having liver disease [91 (76.0% were men, p-value=0.001], 105 (15.4% suffering strokes, 67 (9.9% having metabolic disorders, 51 (7.5% central nervous system infections and 49 (7.2% epilepsy. In the three months following EEG, a survival rate of 75% was found in patients with normal, discreet slow activity or intermittent rhythmic delta activity EEGs, of 50% for those with continuous delta activity and generalized epileptiform discharges, and of 25% for those with burst-suppression, diffuse depression, and in alpha/theta-pattern coma. Death was pronounced immediately in patients with isoelectric EEGs. CONCLUSION: The main findings of EEGs, differentiated different survival rates and are thus a good prognostic tool for patients examined in emergencies.OBJETIVO: Determinar a taxa de sobrevivência (TS, segundo os principais achados de eletrencefalograma de urgência (E-EEG, dos pacientes atendidos nas emergências de hospital de alta complexidade. MÉTODO: Estudo prospectivo, por ordem de chegada, da correlação entre os achados de E-EEG, feitos nos pacientes à beira do leito, com TS, utilizando-se as curvas de sobrevidas de Kaplan Meyer no Hospital de Base de S

  17. The effectiveness of EEG-feedback on attention, impulsivity and EEG : A sham feedback controlled study

    NARCIS (Netherlands)

    Logemann, H. N. Alexander; Lansbergen, Marieke M.; Van Os, Titus W. D. P.; Bocker, Koen B. E.; Kenemans, J. Leon

    2010-01-01

    EEG-feedback, also called neurofeedback, is a training procedure aimed at altering brain activity, and is used as a treatment for disorders like Attention Deficit/Hyperactivity Disorder (ADHD). Studies have reported positive effects of neurofeedback on attention and other dependent variables.

  18. Detecting interictal discharges in first seizure patients: ambulatory EEG or EEG after sleep deprivation?

    NARCIS (Netherlands)

    Geut, I.; Weenink, S.; Knottnerus, I.L.H.; van Putten, Michel J.A.M.

    2017-01-01

    Purpose Uncertainty about recurrence after a first unprovoked seizure is a significant psychological burden for patients, and motivates the need for diagnostic tools with high sensitivity and specificity to assess recurrence risk. As the sensitivity of a routine EEG after a first unprovoked seizure

  19. The default mode network and EEG regional spectral power: a simultaneous fMRI-EEG study.

    Directory of Open Access Journals (Sweden)

    Irene Neuner

    Full Text Available Electroencephalography (EEG frequencies have been linked to specific functions as an "electrophysiological signature" of a function. A combination of oscillatory rhythms has also been described for specific functions, with or without predominance of one specific frequency-band. In a simultaneous fMRI-EEG study at 3 T we studied the relationship between the default mode network (DMN and the power of EEG frequency bands. As a methodological approach, we applied Multivariate Exploratory Linear Optimized Decomposition into Independent Components (MELODIC and dual regression analysis for fMRI resting state data. EEG power for the alpha, beta, delta and theta-bands were extracted from the structures forming the DMN in a region-of-interest approach by applying Low Resolution Electromagnetic Tomography (LORETA. A strong link between the spontaneous BOLD response of the left parahippocampal gyrus and the delta-band extracted from the anterior cingulate cortex was found. A positive correlation between the beta-1 frequency power extracted from the posterior cingulate cortex (PCC and the spontaneous BOLD response of the right supplementary motor cortex was also established. The beta-2 frequency power extracted from the PCC and the precuneus showed a positive correlation with the BOLD response of the right frontal cortex. Our results support the notion of beta-band activity governing the "status quo" in cognitive and motor setup. The highly significant correlation found between the delta power within the DMN and the parahippocampal gyrus is in line with the association of delta frequencies with memory processes. We assumed "ongoing activity" during "resting state" in bringing events from the past to the mind, in which the parahippocampal gyrus is a relevant structure. Our data demonstrate that spontaneous BOLD fluctuations within the DMN are associated with different EEG-bands and strengthen the conclusion that this network is characterized by a specific

  20. Recording EEG In Young Children Without Sedation | Curuneaux ...

    African Journals Online (AJOL)

    Background Although it has been considered that sedation in children undergoing EEG tests is effective and safe and complications are infrequent, occasionally adverse sedation-related events are presented. Objective The aim of this work was to determine if it is possible to carry out EEG in children up to 4 years old ...

  1. EEG Signal Classification With Super-Dirichlet Mixture Model

    DEFF Research Database (Denmark)

    Ma, Zhanyu; Tan, Zheng-Hua; Prasad, Swati

    2012-01-01

    Classification of the Electroencephalogram (EEG) signal is a challengeable task in the brain-computer interface systems. The marginalized discrete wavelet transform (mDWT) coefficients extracted from the EEG signals have been frequently used in researches since they reveal features related to the...

  2. Dynamics of convulsive seizure termination and postictal generalized EEG suppression

    NARCIS (Netherlands)

    Bauer, P.R.; Thijs, R.D.; Lamberts, R.J.; Velis, D.N.; Visser, G.H.; Tolner, E.A.; Sander, J.W.; Lopes da Silva, F.H.; Kalitzin, S.N.

    It is not fully understood how seizures terminate and why some seizures are followed by a period of complete brain activity suppression, postictal generalized EEG suppression. This is clinically relevant as there is a potential association between postictal generalized EEG suppression,

  3. Quantitative EEG Applying the Statistical Recognition Pattern Method

    DEFF Research Database (Denmark)

    Engedal, Knut; Snaedal, Jon; Hoegh, Peter

    2015-01-01

    BACKGROUND/AIM: The aim of this study was to examine the discriminatory power of quantitative EEG (qEEG) applying the statistical pattern recognition (SPR) method to separate Alzheimer's disease (AD) patients from elderly individuals without dementia and from other dementia patients. METHODS...

  4. Diagnostic Role of ECG Recording Simultaneously With EEG Testing.

    Science.gov (United States)

    Kendirli, Mustafa Tansel; Aparci, Mustafa; Kendirli, Nurten; Tekeli, Hakan; Karaoglan, Mustafa; Senol, Mehmet Guney; Togrol, Erdem

    2015-07-01

    Arrhythmia is not uncommon in the etiology of syncope which mimics epilepsy. Data about the epilepsy induced vagal tonus abnormalities have being increasingly reported. So we aimed to evaluate what a neurologist may gain by a simultaneous electrocardiogram (ECG) and electroencephalogram (EEG) recording in the patients who underwent EEG testing due to prediagnosis of epilepsy. We retrospectively evaluated and detected ECG abnormalities in 68 (18%) of 376 patients who underwent EEG testing. A minimum of 20 of minutes artifact-free recording were required for each patient. Standard 1-channel ECG was simultaneously recorded in conjunction with the EEG. In all, 28% of females and 14% of males had ECG abnormalities. Females (mean age 49 years, range 18-88 years) were older compared with the male group (mean age 28 years, range 16-83 years). Atrial fibrillation was more frequent in female group whereas bradycardia and respiratory sinus arrhythmia was higher in male group. One case had been detected a critical asystole indicating sick sinus syndrome in the female group and treated with a pacemaker implantation in the following period. Simultaneous ECG recording in conjunction with EEG testing is a clinical prerequisite to detect and to clarify the coexisting ECG and EEG abnormalities and their clinical relevance. Potentially rare lethal causes of syncope that mimic seizure or those that could cause resistance to antiepileptic therapy could effectively be distinguished by detecting ECG abnormalities coinciding with the signs and abnormalities during EEG recording. © EEG and Clinical Neuroscience Society (ECNS) 2014.

  5. A computerised EEG-analyzing system for small laboratory animals

    NARCIS (Netherlands)

    Kropveld, D.; Chamuleau, R. A.; Popken, R. J.; Smith, J.

    1983-01-01

    The experimental setup, including instrumentation and software packaging, is described for the use of a minicomputer as an on-line analyzing system of the EEG in rats. Complete fast Fourier transformation of the EEG sampled in 15 episodes of 10 s each is plotted out within 7 min after the start of

  6. Quantitative EEG evaluation in patients with acute encephalopathy

    Directory of Open Access Journals (Sweden)

    Aline Souza Marques da Silva Braga

    2013-12-01

    Full Text Available Objective To investigate the use of quantitative EEG (qEEG in patients with acute encephalopathies (AEs and EEG background abnormalities. Method Patients were divided into favorable outcome (group A, 43 patients and an unfavorable outcome (group B, 5 patients. EEGLAB software was used for the qEEG analysis. A graphic of the spectral power from all channels was generated for each participant. Statistical comparisons between the groups were performed. Results In group A, spectral analysis revealed spectral peaks (theta and alpha frequency bands in 84% (38/45 of the patients. In group B, a spectral peak in the delta frequency range was detected in one patient. The remainder of the patients in both groups did not present spectral peaks. Statistical analysis showed lower frequencies recorded from the posterior electrodes in group B patients. Conclusion qEEG may be useful in the evaluations of patients with AEs by assisting with the prognostic determination.

  7. Standardized computer-based organized reporting of EEG

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Aurlien, Harald; Brøgger, Jan C.

    2017-01-01

    are used to report the features of clinical relevance, extracted while assessing the EEGs. Selection of the terms is context sensitive: initial choices determine the subsequently presented sets of additional choices. This process automatically generates a report and feeds these features into a database......Standardized terminology for computer-based assessment and reporting of EEG has been previously developed in Europe. The International Federation of Clinical Neurophysiology established a taskforce in 2013 to develop this further, and to reach international consensus. This work resulted...... in the second, revised version of SCORE (Standardized Computer-based Organized Reporting of EEG), which is presented in this paper. The revised terminology was implemented in a software package (SCORE EEG), which was tested in clinical practice on 12,160 EEG recordings. Standardized terms implemented in SCORE...

  8. [EEG in Parkinson's disease and cerebral hypoxia (author's transl)].

    Science.gov (United States)

    Girke, W; Löwe, H P; Xenakis, C

    1978-03-01

    EEG-findings of a group of 95 patients suffering from Parkinson's disease were related to accompanying diseases inducing cerebral hypoxic hypoxidosis. The EEG in 59 to 74 per cent of our patients was abnormal but the changes were not specific. There was a correlation between age and EEG-abnormalities. On the other hand no association could be seen between EEG-changes and duration of the Parkinson's disease. At least 74 per cent of the patients suffered from concomitant cardiovascular complications and 36 of them had a severe pathologic EEG as well as a pathologic ECG. The results lead to the conclusion that in treatment of parkinsonian patients attention is to be paid to accompanying diseases as heart failure, angiopathy or anemia.

  9. [Qualitative and quantitative EEG-findings in schizophrenia (author's transl)].

    Science.gov (United States)

    Itil, T M

    1978-03-01

    The results of the qualitative but particularly the quantitative EEG-studies indicate that 1. The EEG of adult schizophrenics is characterized by an appearance of excessive fast activity along with some slow waves and the lack of alpha-activity. 2. Excessive fast activity and lack of alpha-waves have also been found in the EEGs of psychotic children and most interestingly in children whose parents (particularly the mother) are schizophrenic (high risk children). 3. Based on the studies during sleep and investigations with neuroleptics, it was established that the origin of the excess fast activity in schizophrenia cannot be the muscle potential. Particularly the excess fast activity in high risk children for schizophrenia goes against the muscle potential hypothesis. 4. The quantitative EEG changes seen in schizophrenia show similarity to those seen after hallucinogenic compounds particularly after anticholinergic hallucinogenics. 5. All neuroleptics (major tranquilizers) produce quantitative EEG alterations which are almost diametrically opposite to those seen in schizoprenia.

  10. Data-driven forward model inference for EEG brain imaging

    DEFF Research Database (Denmark)

    Hansen, Sofie Therese; Hauberg, Søren; Hansen, Lars Kai

    2016-01-01

    . Combined with only a recorded EEG signal, we are able to estimate both the brain sources and a person-specific forward model by optimizing this parametrization. We thus not only solve an inverse problem, but also optimize over its specification. Our work demonstrates that personalized EEG brain imaging......Electroencephalography (EEG) is a flexible and accessible tool with excellent temporal resolution but with a spatial resolution hampered by volume conduction. Reconstruction of the cortical sources of measured EEG activity partly alleviates this problem and effectively turns EEG into a brain...... imaging device. The quality of the source reconstruction depends on the forward model which details head geometry and conductivities of different head compartments. These person-specific factors are complex to determine, requiring detailed knowledge of the subject’s anatomy and physiology. In this proof...

  11. EEG Suppression Associated with Apneic Episodes in a Neonate

    Directory of Open Access Journals (Sweden)

    Evonne Low

    2012-01-01

    Full Text Available We describe the EEG findings from an ex-preterm neonate at term equivalent age who presented with intermittent but prolonged apneic episodes which were presumed to be seizures. A total of 8 apneic episodes were captured (duration 23–376 seconds during EEG monitoring. The baseline EEG activity was appropriate for corrected gestational age and no electrographic seizure activity was recorded. The average baseline heart rate was 168 beats per minute (bpm and the baseline oxygen saturation level was in the mid-nineties. Periods of complete EEG suppression lasting 68 and 179 seconds, respectively, were recorded during 2 of these 8 apneic episodes. Both episodes were accompanied by bradycardia less than 70 bpm and oxygen saturation levels of less than 20%. Short but severe episodes of apnea can cause complete EEG suppression in the neonate.

  12. Comparative EEG mapping studies in Huntington's disease patients and controls.

    Science.gov (United States)

    Painold, Annamaria; Anderer, Peter; Holl, Anna K; Letmaier, Martin; Saletu-Zyhlarz, Gerda M; Saletu, Bernd; Bonelli, Raphael M

    2010-11-01

    Huntington's disease (HD) is a devastating neurodegenerative disorder with prominent motor and cognitive decline. Previous studies with small sample sizes and methodological limitations have described abnormal electroencephalograms (EEG) in this cohort. The aim of the present study was to investigate objectively and quantitatively the neurophysiological basis of the disease in HD patients as compared to normal controls, utilizing EEG mapping. In 55 HD patients and 55 healthy controls, a 3-min vigilance-controlled EEG (V-EEG) was recorded during midmorning hours. Evaluation of 36 EEG variables was carried out by spectral analysis and visualized by EEG mapping techniques. To elucidate drug interference, the analysis was performed for the total group, unmedicated patients only and between treated and untreated patients. Statistical overall analysis by the omnibus significance test demonstrated significant (p < 0.01 and p < 0.05) EEG differences between HD patients and controls. Subsequent univariate analysis revealed a general decrease in total power and absolute alpha and beta power, an increase in delta/theta power, and a slowing of the centroids of delta/theta, beta and total power. The slowing of the EEG in HD reflects a disturbed brain function in the sense of a vigilance decrement, electrophysiologically characterized by inhibited cortical areas (increased delta/theta power) and a lack of normal routine and excitatory activity (decreased alpha and beta power). The results are similar to those found in other dementing disorders. Medication did not affect the overall interpretation of the quantitative EEG analysis, but certain differences might be due to drug interaction, predominantly with antipsychotics. Spearman rank correlations revealed significant correlations between EEG mapping and cognitive and motor impairment in HD patients.

  13. Functional Mapping with Simultaneous MEG and EEG.

    Science.gov (United States)

    Liu, Hesheng; Tanaka, Naoaki; Stufflebeam, Steven; Ahlfors, Seppo; Hämäläinen, Matti

    2010-06-14

    We use magnetoencephalography (MEG) and electroencephalography (EEG) to locate and determine the temporal evolution in brain areas involved in the processing of simple sensory stimuli. We will use somatosensory stimuli to locate the hand somatosensory areas, auditory stimuli to locate the auditory cortices, visual stimuli in four quadrants of the visual field to locate the early visual areas. These type of experiments are used for functional mapping in epileptic and brain tumor patients to locate eloquent cortices. In basic neuroscience similar experimental protocols are used to study the orchestration of cortical activity. The acquisition protocol includes quality assurance procedures, subject preparation for the combined MEG/EEG study, and acquisition of evoked-response data with somatosensory, auditory, and visual stimuli. We also demonstrate analysis of the data using the equivalent current dipole model and cortically-constrained minimum-norm estimates. Anatomical MRI data are employed in the analysis for visualization and for deriving boundaries of tissue boundaries for forward modeling and cortical location and orientation constraints for the minimum-norm estimates.

  14. EEG microstates during resting represent personality differences.

    Science.gov (United States)

    Schlegel, Felix; Lehmann, Dietrich; Faber, Pascal L; Milz, Patricia; Gianotti, Lorena R R

    2012-01-01

    We investigated the spontaneous brain electric activity of 13 skeptics and 16 believers in paranormal phenomena; they were university students assessed with a self-report scale about paranormal beliefs. 33-channel EEG recordings during no-task resting were processed as sequences of momentary potential distribution maps. Based on the maps at peak times of Global Field Power, the sequences were parsed into segments of quasi-stable potential distribution, the 'microstates'. The microstates were clustered into four classes of map topographies (A-D). Analysis of the microstate parameters time coverage, occurrence frequency and duration as well as the temporal sequence (syntax) of the microstate classes revealed significant differences: Believers had a higher coverage and occurrence of class B, tended to decreased coverage and occurrence of class C, and showed a predominant sequence of microstate concatenations from A to C to B to A that was reversed in skeptics (A to B to C to A). Microstates of different topographies, putative "atoms of thought", are hypothesized to represent different types of information processing.The study demonstrates that personality differences can be detected in resting EEG microstate parameters and microstate syntax. Microstate analysis yielded no conclusive evidence for the hypothesized relation between paranormal belief and schizophrenia.

  15. Optimizing microsurgical skills with EEG neurofeedback

    Directory of Open Access Journals (Sweden)

    Benjamin Larry

    2009-07-01

    Full Text Available Abstract Background By enabling individuals to self-regulate their brainwave activity in the field of optimal performance in healthy individuals, neurofeedback has been found to improve cognitive and artistic performance. Here we assessed whether two distinct EEG neurofeedback protocols could develop surgical skill, given the important role this skill plays in medicine. Results National Health Service trainee ophthalmic microsurgeons (N = 20 were randomly assigned to either Sensory Motor Rhythm-Theta (SMR or Alpha-Theta (AT groups, a randomized subset of which were also part of a wait-list 'no-treatment' control group (N = 8. Neurofeedback groups received eight 30-minute sessions of EEG training. Pre-post assessment included a skills lab surgical procedure with timed measures and expert ratings from video-recordings by consultant surgeons, together with state/trait anxiety self-reports. SMR training demonstrated advantages absent in the control group, with improvements in surgical skill according to 1 the expert ratings: overall technique (d = 0.6, p Conclusion SMR-Theta neurofeedback training provided significant improvement in surgical technique whilst considerably reducing time on task by 26%. There was also evidence that AT training marginally reduced total surgery time, despite suboptimal training efficacies. Overall, the data set provides encouraging evidence of optimised learning of a complex medical specialty via neurofeedback training.

  16. Nonlinear analysis of EEG for epileptic seizures

    Energy Technology Data Exchange (ETDEWEB)

    Hively, L.M.; Clapp, N.E.; Daw, C.S.; Lawkins, W.F. [Oak Ridge National Lab., TN (United States); Eisenstadt, M.L. [Knoxville Neurology Clinic, St. Mary`s Medical Center, Knoxville, TN (United States)

    1995-04-01

    We apply chaotic time series analysis (CTSA) to human electroencephalogram (EEG) data. Three epoches were examined: epileptic seizure, non-seizure, and transition from non-seizure to seizure. The CTSA tools were applied to four forms of these data: raw EEG data (e-data), artifact data (f-data) via application of a quadratic zero-phase filter of the raw data, artifact-filtered data (g- data) and that was the residual after subtracting f-data from e-data, and a low-pass-filtered version (h-data) of g-data. Two different seizures were analyzed for the same patient. Several nonlinear measures uniquely indicate an epileptic seizure in both cases, including an abrupt decrease in the time per wave cycle in f-data, an abrupt increase in the Kolmogorov entropy and in the correlation dimension for e-h data, and an abrupt increase in the correlation dimension for e-h data. The transition from normal to seizure state also is characterized by distinctly different trends in the nonlinear measures for each seizure and may be potential seizure predictors for this patient. Surrogate analysis of e-data shows that statistically significant nonlinear structure is present during the non-seizure, transition , and seizure epoches.

  17. Combined EEG/MEG can outperform single modality EEG or MEG source reconstruction in presurgical epilepsy diagnosis.

    Directory of Open Access Journals (Sweden)

    Ümit Aydin

    Full Text Available We investigated two important means for improving source reconstruction in presurgical epilepsy diagnosis. The first investigation is about the optimal choice of the number of epileptic spikes in averaging to (1 sufficiently reduce the noise bias for an accurate determination of the center of gravity of the epileptic activity and (2 still get an estimation of the extent of the irritative zone. The second study focuses on the differences in single modality EEG (80-electrodes or MEG (275-gradiometers and especially on the benefits of combined EEG/MEG (EMEG source analysis. Both investigations were validated with simultaneous stereo-EEG (sEEG (167-contacts and low-density EEG (ldEEG (21-electrodes. To account for the different sensitivity profiles of EEG and MEG, we constructed a six-compartment finite element head model with anisotropic white matter conductivity, and calibrated the skull conductivity via somatosensory evoked responses. Our results show that, unlike single modality EEG or MEG, combined EMEG uses the complementary information of both modalities and thereby allows accurate source reconstructions also at early instants in time (epileptic spike onset, i.e., time points with low SNR, which are not yet subject to propagation and thus supposed to be closer to the origin of the epileptic activity. EMEG is furthermore able to reveal the propagation pathway at later time points in agreement with sEEG, while EEG or MEG alone reconstructed only parts of it. Subaveraging provides important and accurate information about both the center of gravity and the extent of the epileptogenic tissue that neither single nor grand-averaged spike localizations can supply.

  18. Combined EEG/MEG can outperform single modality EEG or MEG source reconstruction in presurgical epilepsy diagnosis.

    Science.gov (United States)

    Aydin, Ümit; Vorwerk, Johannes; Dümpelmann, Matthias; Küpper, Philipp; Kugel, Harald; Heers, Marcel; Wellmer, Jörg; Kellinghaus, Christoph; Haueisen, Jens; Rampp, Stefan; Stefan, Hermann; Wolters, Carsten H

    2015-01-01

    We investigated two important means for improving source reconstruction in presurgical epilepsy diagnosis. The first investigation is about the optimal choice of the number of epileptic spikes in averaging to (1) sufficiently reduce the noise bias for an accurate determination of the center of gravity of the epileptic activity and (2) still get an estimation of the extent of the irritative zone. The second study focuses on the differences in single modality EEG (80-electrodes) or MEG (275-gradiometers) and especially on the benefits of combined EEG/MEG (EMEG) source analysis. Both investigations were validated with simultaneous stereo-EEG (sEEG) (167-contacts) and low-density EEG (ldEEG) (21-electrodes). To account for the different sensitivity profiles of EEG and MEG, we constructed a six-compartment finite element head model with anisotropic white matter conductivity, and calibrated the skull conductivity via somatosensory evoked responses. Our results show that, unlike single modality EEG or MEG, combined EMEG uses the complementary information of both modalities and thereby allows accurate source reconstructions also at early instants in time (epileptic spike onset), i.e., time points with low SNR, which are not yet subject to propagation and thus supposed to be closer to the origin of the epileptic activity. EMEG is furthermore able to reveal the propagation pathway at later time points in agreement with sEEG, while EEG or MEG alone reconstructed only parts of it. Subaveraging provides important and accurate information about both the center of gravity and the extent of the epileptogenic tissue that neither single nor grand-averaged spike localizations can supply.

  19. Advantages of respiratory monitoring during video-EEG evaluation to differentiate epileptic seizures from other events

    Science.gov (United States)

    Pavlova, Milena; Abdennadher, Myriam; Singh, Kanwaljit; Katz, Eliot; Llewellyn, Nichelle; Zarowsly, Marcin; White, David P.; Dworetzky, Barbara A.; Kothare, Sanjeev V.

    2014-01-01

    Distinction between epileptic (ES) and seizure-like events of non-epileptic nature(SLNE) is often difficult using descriptions of seizure semiology. Cardiopulmonary dysfunction is frequent in ES but has not been objectively examined in relationship to SLNE. Our purpose was to compare cardiopulmonary dysfunction between ES and SLNE. We prospectively recorded cardio-pulmonary function using pulse-oximetry, EKG and respiratory inductance plethysmography (RIP) in 52 ES and 22 SLNE. Comparison of cardiopulmonary complications between ES and SLNE was done using two-sample t-tests and logistic regression. Ictal bradypnea and pre-ictal bradycardia were more frequent in ES than SLNE (p1.0). Cardio-respiratory dysfunction, specifically bradypnea, apnea, pre-ictal bradycardia, and oxygen desaturation, is more frequently seen in ES than in SLNE. Tachycardia was not discriminant between ES and SLNE. PMID:24561659

  20. Behavioral measures and EEG monitoring using the Brain Symmetry Index during the Wada test in children

    NARCIS (Netherlands)

    Peters, J.M.; Tomas-Fernandez, Meritxell; van Putten, Michel Johannes Antonius Maria; Loddenkemper, Tobias

    2012-01-01

    EEG monitoring is used routinely during the Wada test in children. We quantified EEG asymmetry using the Brain Symmetry Index (BSI) to reduce subjectivity of EEG interpretation. Clinical and procedural variables were obtained and EEG data were retrieved from 46 patients with a total of 89

  1. The relationship between intra-operative entropy of the EEG and ...

    African Journals Online (AJOL)

    Adele

    Background. Entropy is based on the extent of order in both the cortical EEG and facial EMG (FEMG) signals, measured from the patient's forehead. Order equals regularity of the EEG signal. In an awake patient, the. EEG is very irregular and the entropy high. As the level of anesthesia deepens, the EEG becomes more ...

  2. Discovering EEG resting state alterations of semantic dementia.

    Science.gov (United States)

    Grieder, Matthias; Koenig, Thomas; Kinoshita, Toshihiko; Utsunomiya, Keita; Wahlund, Lars-Olof; Dierks, Thomas; Nishida, Keiichiro

    2016-05-01

    Diagnosis of semantic dementia relies on cost-intensive MRI or PET, although resting EEG markers of other dementias have been reported. Yet the view still holds that resting EEG in patients with semantic dementia is normal. However, studies using increasingly sophisticated EEG analysis methods have demonstrated that slightest alterations of functional brain states can be detected. We analyzed the common four resting EEG microstates (A, B, C, and D) of 8 patients with semantic dementia in comparison with 8 healthy controls and 8 patients with Alzheimer's disease. Topographical differences between the groups were found in microstate classes B and C, while microstate classes A and D were comparable. The data showed that the semantic dementia group had a peculiar microstate E, but the commonly found microstate C was lacking. Furthermore, the presence of microstate E was significantly correlated with lower MMSE and language scores. Alterations in resting EEG can be found in semantic dementia. Topographical shifts in microstate C might be related to semantic memory deficits. This is the first study that discovered resting state EEG abnormality in semantic dementia. The notion that resting EEG in this dementia subtype is normal has to be revised. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Higher-Order Spectrum in Understanding Nonlinearity in EEG Rhythms

    Directory of Open Access Journals (Sweden)

    Cauchy Pradhan

    2012-01-01

    Full Text Available The fundamental nature of the brain's electrical activities recorded as electroencephalogram (EEG remains unknown. Linear stochastic models and spectral estimates are the most common methods for the analysis of EEG because of their robustness, simplicity of interpretation, and apparent association with rhythmic behavioral patterns in nature. In this paper, we extend the use of higher-order spectrum in order to indicate the hidden characteristics of EEG signals that simply do not arise from random processes. The higher-order spectrum is an extension Fourier spectrum that uses higher moments for spectral estimates. This essentially nullifies all Gaussian random effects, therefore, can reveal non-Gaussian and nonlinear characteristics in the complex patterns of EEG time series. The paper demonstrates the distinguishing features of bispectral analysis for chaotic systems, filtered noises, and normal background EEG activity. The bispectrum analysis detects nonlinear interactions; however, it does not quantify the coupling strength. The squared bicoherence in the nonredundant region has been estimated to demonstrate nonlinear coupling. The bicoherence values are minimal for white Gaussian noises (WGNs and filtered noises. Higher bicoherence values in chaotic time series and normal background EEG activities are indicative of nonlinear coupling in these systems. The paper shows utility of bispectral methods as an analytical tool in understanding neural process underlying human EEG patterns.

  4. Pattern classification of EEG signals reveals perceptual and attentional states.

    Science.gov (United States)

    List, Alexandra; Rosenberg, Monica D; Sherman, Aleksandra; Esterman, Michael

    2017-01-01

    Pattern classification techniques have been widely used to differentiate neural activity associated with different perceptual, attentional, or other cognitive states, often using fMRI, but more recently with EEG as well. Although these methods have identified EEG patterns (i.e., scalp topographies of EEG signals occurring at certain latencies) that decode perceptual and attentional states on a trial-by-trial basis, they have yet to be applied to the spatial scope of attention toward global or local features of the display. Here, we initially used pattern classification to replicate and extend the findings that perceptual states could be reliably decoded from EEG. We found that visual perceptual states, including stimulus location and object category, could be decoded with high accuracy peaking between 125-250 ms, and that the discriminative spatiotemporal patterns mirrored and extended our (and other well-established) ERP results. Next, we used pattern classification to investigate whether spatiotemporal EEG signals could reliably predict attentional states, and particularly, the scope of attention. The EEG data were reliably differentiated for local versus global attention on a trial-by-trial basis, emerging as a specific spatiotemporal activation pattern over posterior electrode sites during the 250-750 ms interval after stimulus onset. In sum, we demonstrate that multivariate pattern analysis of EEG, which reveals unique spatiotemporal patterns of neural activity distinguishing between behavioral states, is a sensitive tool for characterizing the neural correlates of perception and attention.

  5. Usability of four commercially-oriented EEG systems

    Science.gov (United States)

    Hairston, W. David; Whitaker, Keith W.; Ries, Anthony J.; Vettel, Jean M.; Cortney Bradford, J.; Kerick, Scott E.; McDowell, Kaleb

    2014-08-01

    Electroencephalography (EEG) holds promise as a neuroimaging technology that can be used to understand how the human brain functions in real-world, operational settings while individuals move freely in perceptually-rich environments. In recent years, several EEG systems have been developed that aim to increase the usability of the neuroimaging technology in real-world settings. Here, the usability of three wireless EEG systems from different companies are compared to a conventional wired EEG system, BioSemi’s ActiveTwo, which serves as an established laboratory-grade ‘gold standard’ baseline. The wireless systems compared include Advanced Brain Monitoring’s B-Alert X10, Emotiv Systems’ EPOC and the 2009 version of QUASAR’s Dry Sensor Interface 10-20. The design of each wireless system is discussed in relation to its impact on the system’s usability as a potential real-world neuroimaging system. Evaluations are based on having participants complete a series of cognitive tasks while wearing each of the EEG acquisition systems. This report focuses on the system design, usability factors and participant comfort issues that arise during the experimental sessions. In particular, the EEG systems are assessed on five design elements: adaptability of the system for differing head sizes, subject comfort and preference, variance in scalp locations for the recording electrodes, stability of the electrical connection between the scalp and electrode, and timing integration between the EEG system, the stimulus presentation computer and other external events.

  6. Sleepwalking and night terrors in adulthood clinical EEG findings.

    Science.gov (United States)

    Soldatos, C R; Vela-Bueno, A; Bixler, E O; Schweitzer, P K; Kales, A

    1980-07-01

    This is the first controlled study to show a lack of relation between a positive history of sleepwalking or night terrors in adults and daytime EEG abnormalities. We recorded a standard clinical EEG on 35 adult sleepwalkers (SW), 35 adult night terror patients (NT), and 35 control subjects (CS). Three subjects in the SW group showed abnormalities: one during both the resting record (RR) and hyperventilation (HV), and two only during HV. None in the NT group showed any EEG abnormality. Two control subjects showed abnormalities of both RR and HV, and a third only during HV. The number of abnormal EEGs within each group was limited, and the three groups did not significantly differ from one another. Our results suggest that the daytime clinical EEG is of limited value in evaluating adults with the primary complaint of sleepwalking or night terrors. However, further all-night sleep EEG studies utilizing clinical montage are needed to investigate the temporal relationship of sleepwalking and night terror events to possible EEG abnormalities.

  7. Study on non-linear bistable dynamics model based EEG signal discrimination analysis method.

    Science.gov (United States)

    Ying, Xiaoguo; Lin, Han; Hui, Guohua

    2015-01-01

    Electroencephalogram (EEG) is the recording of electrical activity along the scalp. EEG measures voltage fluctuations generating from ionic current flows within the neurons of the brain. EEG signal is looked as one of the most important factors that will be focused in the next 20 years. In this paper, EEG signal discrimination based on non-linear bistable dynamical model was proposed. EEG signals were processed by non-linear bistable dynamical model, and features of EEG signals were characterized by coherence index. Experimental results showed that the proposed method could properly extract the features of different EEG signals.

  8. Utility of Independent Component Analysis for Interpretation of Intracranial EEG

    Directory of Open Access Journals (Sweden)

    Diane eWhitmer

    2010-11-01

    Full Text Available Electrode arrays are sometimes implanted in the brains of patients with intractable epilepsy to better localize seizure foci before epilepsy surgery. Analysis of intracranial EEG (iEEG recordings is typically performed in the electrode channel domain without explicit separation of the sources that generate the signals. However, intracranial EEG signals, like scalp EEG signals, could be linear mixtures of local activity and volume conducted activity arising in multiple source areas. Independent component analysis (ICA has recently been applied to scalp EEG data, and shown to separate the signal mixtures into independently generated brain and non-brain source signals. Here, we applied ICA to un-mix source signals from intracranial EEG recordings from four epilepsy patients during a visually cued finger movement task in the presence of background pathological brain activity. This ICA decomposition demonstrated that the iEEG recordings were not maximally independent, but rather are linear mixtures of activity from multiple sources. Many of the independent component (IC projections to the iEEG recording grid were consistent with sources from single brain regions, including components exhibiting classic movement-related dynamics. Notably, the largest IC projection to each channel accounted for no more than 20%-80% of the channel signal variance, implying that in general intracranial recordings cannot be accurately interpreted as recordings of independent brain sources. These results suggest that ICA can be used to identify and monitor major field sources of local and distributed functional networks generating iEEG data. ICA decomposition methods are useful for improving the fidelity of source signals of interest, likely including distinguishing the sources of pathological brain activity.

  9. Automated approach to detecting behavioral states using EEG-DABS

    Directory of Open Access Journals (Sweden)

    Zachary B. Loris

    2017-07-01

    Full Text Available Electrocorticographic (ECoG signals represent cortical electrical dipoles generated by synchronous local field potentials that result from simultaneous firing of neurons at distinct frequencies (brain waves. Since different brain waves correlate to different behavioral states, ECoG signals presents a novel strategy to detect complex behaviors. We developed a program, EEG Detection Analysis for Behavioral States (EEG-DABS that advances Fast Fourier Transforms through ECoG signals time series, separating it into (user defined frequency bands and normalizes them to reduce variability. EEG-DABS determines events if segments of an experimental ECoG record have significantly different power bands than a selected control pattern of EEG. Events are identified at every epoch and frequency band and then are displayed as output graphs by the program. Certain patterns of events correspond to specific behaviors. Once a predetermined pattern was selected for a behavioral state, EEG-DABS correctly identified the desired behavioral event. The selection of frequency band combinations for detection of the behavior affects accuracy of the method. All instances of certain behaviors, such as freezing, were correctly identified from the event patterns generated with EEG-DABS. Detecting behaviors is typically achieved by visually discerning unique animal phenotypes, a process that is time consuming, unreliable, and subjective. EEG-DABS removes variability by using defined parameters of EEG/ECoG for a desired behavior over chronic recordings. EEG-DABS presents a simple and automated approach to quantify different behavioral states from ECoG signals.

  10. Polysomnography with quantitative EEG in patients with and without fibromyalgia.

    Science.gov (United States)

    Rosenfeld, Victor W; Rutledge, Dana N; Stern, John M

    2015-04-01

    Characterize the polysomnographic (PSG) and quantitative EEG (qEEG) features of fibromyalgia and determine whether fibromyalgia patients differ in these measures when compared with a control sleep disorder population. All undergoing all-night PSG for evaluation of a sleep disorder were evaluated for fibromyalgia. The PSGs were interpreted for routine sleep measures, and qEEG was performed to measure the delta and alpha frequency power during non-rapid eye movement sleep. Measures and qEEG were analyzed according to fibromyalgia diagnosis. Community-based sleep medicine center. All patients undergoing PSG over a 2-year period. None. Of the 385 patients in the study population, 133 had fibromyalgia according to American College of Rheumatology criteria. The population's average Epworth Sleepiness Score was 10.5, the average sleep efficiency was 78%, and the Periodic Limb Movement disorder prevalence was 15%. None of these sleep measures differed significantly between the fibromyalgia and non-fibromyalgia groups. Obstructive sleep apnea was present in 45% of the fibromyalgia group. Significant differences were present in the qEEG ratio of delta to alpha frequency power, which was 95% specific for fibromyalgia when ≤1. A qEEG ratio ≤10.5 was 85% sensitive for fibromyalgia, and a qEEG ratio >10.5 had an 89% negative predictive value for fibromyalgia. Among patients with fibromyalgia who were not taking a benzodiazepine or benzodiazepine agonist, a qEEG ratio ≤10.5 was 84% specific and had a 78% positive predictive value. Sleep disorders identified by routine PSG, including obstructive sleep apnea, are common in fibromyalgia, but periodic leg movement disorder and poor sleep efficiency are not. A qEEG low delta/alpha ratio during non-rapid eye movement sleep can differentiate patients with fibromyalgia from others who are referred for PSG. Consideration of benzodiazepine and benzodiazepine agonist use is important when interpreting the delta/alpha ratio.

  11. Prospective motion correction for MRI using EEG-equipment

    DEFF Research Database (Denmark)

    Andersen, Mads; Madsen, Kristoffer Hougaard; Hanson, Lars G.

    2016-01-01

    A new prospective motion correction technique is presented that is based on signals from gradient switching, in an EEG-cap with interconnected electrodes the subject wears during scanning. The method has no line-of-sight limitations as optical methods, requires no interleaved navigator modules or...... or additional hardware for sites already doing EEG-fMRI. Instead a training scan is performed were signals recorded with the EEG-system are correlated with motion parameters estimated by image realignment. Initial results from application of the method in a phantom are promising....

  12. Implantation of an EEG telemetric transmitter in the rat.

    Science.gov (United States)

    Cotugno, M; Mandile, P; D'Angiolillo, D; Montagnese, P; Giuditta, A

    1996-04-01

    We describe a method of implanting a telemetric transmitter of EEG signals in the laboratory rat. The transmitter is available commercially and may be implanted in a subcutaneous pocket prepared in the hindermost dorsal region of the animal. The two stainless steel electrodes connected to the transmitter are led to the cranium through a subcutaneous tunnel, and are fixed to the cranium bones. EEG signals are collected by a receiver placed under the cage; reception of the signals is improved by suitably placed antennae. The method allows recording of EEG data from a free-moving rat during the expression of behavioral tasks in a limited space.

  13. EEG Artifact Removal Using a Wavelet Neural Network

    Science.gov (United States)

    Nguyen, Hoang-Anh T.; Musson, John; Li, Jiang; McKenzie, Frederick; Zhang, Guangfan; Xu, Roger; Richey, Carl; Schnell, Tom

    2011-01-01

    !n this paper we developed a wavelet neural network. (WNN) algorithm for Electroencephalogram (EEG) artifact removal without electrooculographic (EOG) recordings. The algorithm combines the universal approximation characteristics of neural network and the time/frequency property of wavelet. We. compared the WNN algorithm with .the ICA technique ,and a wavelet thresholding method, which was realized by using the Stein's unbiased risk estimate (SURE) with an adaptive gradient-based optimal threshold. Experimental results on a driving test data set show that WNN can remove EEG artifacts effectively without diminishing useful EEG information even for very noisy data.

  14. Added clinical value of the inferior temporal EEG electrode chain

    DEFF Research Database (Denmark)

    Bach Justesen, Anders; Eskelund Johansen, Ann Berit; Martinussen, Noomi Ida

    2018-01-01

    Objective To investigate the diagnostic added value of supplementing the 10–20 EEG array with six electrodes in the inferior temporal chain. Methods EEGs were recorded with 25 electrodes: 19 positions of the 10–20 system, and six additional electrodes in the inferior temporal chain (F9/10, T9/10, P...... in the inferior chain) and 6% (only seen at the inferior chain). Conclusions Adding six electrodes in the inferior temporal electrode chain to the 10–20 array improves the localization and identification of EEG abnormalities, especially those located in the temporal region. Significance Our results suggest...

  15. Efficiency analysis of voluntary control of human's EEG spectral characteristics.

    Science.gov (United States)

    Kiroy, Valery N; Aslanyan, Elena V; Lazurenko, Dmitry M; Minyaeva, Nadezhda R; Bakhtin, Oleg M

    2016-03-01

    Spectral power (SP) of EEG alpha and beta-2 frequencies in different cortical areas has been used for neurofeedback training to control a graphic interface in different scenarios. The results show that frequency range and brain cortical areas are associated with high or low efficiency of voluntary control. Overall, EEG phenomena observed in the course of training are largely general changes involving extensive brain areas and frequency bands. Finally, we have demonstrated EEG patterns that dynamically switch with a specific feature in different tasks within one training, after a relatively short period of training.

  16. A FDM anisotropic formulation for EEG simulation.

    Science.gov (United States)

    Bruno, P; Hyttinen, J; Inchingolo, P; Magrofuoco, A; Mininel, S; Vatta, F

    2006-01-01

    Accurate head modeling is required to properly simulate bioelectric phenomena in 3-D as well as to estimate the 3-D bioelectric activity starting from superficial bioelectric measurements and 3-D imaging. Aiming to build an accurate and realistic representation of the volume conductor of the head, also the anisotropy of head tissues should be taken into account. In this paper we describe a new finite-difference method (FDM) formulation which accounts for anisotropy of the various head tissues. Our proposal, being based on FDM, derives the head model directly from patient's specific clinical images. We present here the details of the numerical formulation and the method validation by comparing our numerical proposal and known analytical results using a multi-shell anisotropic head model with skull anisotropy. Furthermore, we analyzed also different numerical grid refinement and EEG source characteristics. The comparison with previously developed FDM methods shows a good performance of the proposed method.

  17. Generalized periodic EEG activity in two cases of neurosyphilis

    Directory of Open Access Journals (Sweden)

    Anghinah Renato

    2006-01-01

    Full Text Available Neurosyphilis is a recognized cause of epileptic seizures and cognitive impairment, but is not usually associated with the finding of generalized periodic activity in the EEG. We report two similar cases characterized by progressive cognitive impairment followed by partial complex seizures, in whom the EEG showed generalized periodic activity. Both cerebrospinal fluid and the response to penicillin therapy confirmed the diagnoses of neurosyphilis in the two cases. The finding of EEG generalized periodic activity in patients with cognitive or behavioral disorders is usually associated with Creutzfeldt-Jakob disease, although there are other conditions, some of them potentially reversible, which may also present this EEG abnormality. Neurosyphilis has tended not to be included among them, and our present findings support the importance of first ruling out neurosyphilis in those patients with cognitive or behavioral disorders associated with generalized periodic epileptiform discharges.

  18. EEG. Renewables Act. Comment. 4. new rev. and enl. ed.

    International Nuclear Information System (INIS)

    Frenz, Walter; Cosack, Tilman

    2015-01-01

    Unlike any other Act, the Renewable Energy Sources Act (EEG) changes continuously. Recently it has been fundamentally transformed with the amendment 2014. Comprehensive, readable and practice-oriented. The proven Berliner comment EEG is your reliable companion through the new regulatory regime. All provisions of the EEG 2014 thorough and easy to understand commented by experts of the matter. 2. The EEG Amending Act of 29.6.2015 has already been considered. A detailed introduction and contributions to the relevant European law and the antitrust aspects of the renewable energy sources to guarantee you a broad understanding of the rules. Valuable background information you provide, the digressions of the most important renewable energy technologies, will explain the pictures thanks to numerous the scientific and technical foundations. Moreover you the construction law aspects in the construction of photovoltaic and wind turbines are explained clearly. [de

  19. Improving EEG signal peak detection using feature weight learning ...

    Indian Academy of Sciences (India)

    Asrul Adam

    Neural network with random weights (NNRW); feature weight learning (FWL); electroencephalogram (EEG); peak detection algorithm; pattern recognition; particle swarm optimization (PSO). 1. Introduction. The utilization of peak detection algorithms has emerged as a useful tool in several physiological signal applications,.

  20. ECG contamination of EEG signals: effect on entropy.

    Science.gov (United States)

    Chakrabarti, Dhritiman; Bansal, Sonia

    2016-02-01

    Entropy™ is a proprietary algorithm which uses spectral entropy analysis of electroencephalographic (EEG) signals to produce indices which are used as a measure of depth of hypnosis. We describe a report of electrocardiographic (ECG) contamination of EEG signals leading to fluctuating erroneous Entropy values. An explanation is provided for mechanism behind this observation by describing the spread of ECG signals in head and neck and its influence on EEG/Entropy by correlating the observation with the published Entropy algorithm. While the Entropy algorithm has been well conceived, there are still instances in which it can produce erroneous values. Such erroneous values and their cause may be identified by close scrutiny of the EEG waveform if Entropy values seem out of sync with that expected at given anaesthetic levels.

  1. EEG feature selection method based on decision tree.

    Science.gov (United States)

    Duan, Lijuan; Ge, Hui; Ma, Wei; Miao, Jun

    2015-01-01

    This paper aims to solve automated feature selection problem in brain computer interface (BCI). In order to automate feature selection process, we proposed a novel EEG feature selection method based on decision tree (DT). During the electroencephalogram (EEG) signal processing, a feature extraction method based on principle component analysis (PCA) was used, and the selection process based on decision tree was performed by searching the feature space and automatically selecting optimal features. Considering that EEG signals are a series of non-linear signals, a generalized linear classifier named support vector machine (SVM) was chosen. In order to test the validity of the proposed method, we applied the EEG feature selection method based on decision tree to BCI Competition II datasets Ia, and the experiment showed encouraging results.

  2. An unsupervised subject identification technique using EEG signals.

    Science.gov (United States)

    Birjandtalab, Javad; Pouyan, Maziyar Baran; Nourani, Mehrdad

    2016-08-01

    In this work, EEG spectral features of different subjects are uniquely mapped into a 2D feature space. Such distinctive 2D features pave the way to identify subjects from their EEG spectral characteristics in an unsupervised manner without any prior knowledge. First, we extract power spectral density of EEG signals in different frequency bands. Next, we use t-distributed stochastic neighbor embedding to map data points from high dimensional space in a visible 2D space. Such non-linear data embedding method visualizes different subjects' data points as well-separated islands in two dimensions. We use a fuzzy c-means clustering technique to identify different subjects without any prior knowledge. The experimental results show that our proposed method efficiently (precision greater than 90%) discriminates 10 subjects using only the spectral information within their EEG signals.

  3. SVM detection of epileptiform activity in routine EEG.

    LENUS (Irish Health Repository)

    Kelleher, Daniel

    2010-01-01

    Routine electroencephalogram (EEG) is an important test in aiding the diagnosis of patients with suspected epilepsy. These recordings typically last 20-40 minutes, during which signs of abnormal activity (spikes, sharp waves) are looked for in the EEG trace. It is essential that events of short duration are detected during the routine EEG test. The work presented in this paper examines the effect of changing a range of input values to the detection system on its ability to distinguish between normal and abnormal EEG activity. It is shown that the length of analysis window in the range of 0.5s to 1s are well suited to the task. Additionally, it is reported that patient specific systems should be used where possible due to their better performance.

  4. Interhemispheric asynchrony of the sleep EEG in northern fur seals.

    Science.gov (United States)

    Mukhametov, L M; Lyamin, O I; Polyakova, I G

    1985-08-15

    In northern fur seals the two brain hemispheres can generate the EEG slow waves during sleep not only simultaneously, as in all the terrestrial mammals investigated, but also independently as in dolphins.

  5. Classification of independent components of EEG into multiple artifact classes

    DEFF Research Database (Denmark)

    Frølich, Laura; Andersen, Tobias; Mørup, Morten

    2015-01-01

    In this study, we aim to automatically identify multiple artifact types in EEG. We used multinomial regression to classify independent components of EEG data, selecting from 65 spatial, spectral, and temporal features of independent components using forward selection. The classifier identified...... neural and five nonneural types of components. Between subjects within studies, high classification performances were obtained. Between studies, however, classification was more difficult. For neural versus nonneural classifications, performance was on par with previous results obtained by others. We...

  6. Scalable EEG interpretation using Deep Learning and Schema Descriptors

    OpenAIRE

    Picone, Joseph; Obeid, Iyad; Harabagiu, Sanda

    2016-01-01

    •Focus on addressing a critical market gap in EEG technology – real-time seizure detection for intensive care unit (ICU) and epilepsy monitoring unit (EMU) applications. •The ability to auto-scan EEGs and predict seizures in advance will be a transformational clinical technology. Existing products that seek to increase accuracy and productivity via automatic analysis are limited by high rates of false positives, overwhelming healthcare providers with misleading ...

  7. Bayesian Correlated Component Analysis for inference of joint EEG activation

    DEFF Research Database (Denmark)

    Poulsen, Andreas Trier; Kamronn, Simon Due; Parra, Lucas

    2014-01-01

    We propose a probabilistic generative multi-view model to test the representational universality of human information processing. The model is tested in simulated data and in a well-established benchmark EEG dataset.......We propose a probabilistic generative multi-view model to test the representational universality of human information processing. The model is tested in simulated data and in a well-established benchmark EEG dataset....

  8. Emotion classification using single-channel scalp-EEG recording.

    Science.gov (United States)

    Jalilifard, Amir; Brigante Pizzolato, Ednaldo; Kafiul Islam, Md

    2016-08-01

    Several studies have found evidence for corticolimbic Theta electroencephalographic (EEG) oscillation in the neural processing of visual stimuli perceived as fear or threatening scene. Recent studies showed that neural oscillations' patterns in Theta, Alpha, Beta and Gamma sub-bands play a main role in brain's emotional processing. The main goal of this study is to classify two different emotional states by means of EEG data recorded through a single-electrode EEG headset. Nineteen young subjects participated in an EEG experiment while watching a video clip that evoked three emotional states: neutral, relaxation and scary. Following each video clip, participants were asked to report on their subjective affect by giving a score between 0 to 10. First, recorded EEG data were preprocessed by stationary wavelet transform (SWT) based denoising to remove artifacts. Afterward, the distribution of power in time-frequency space was obtained using short-time Fourier transform (STFT) and then, the mean value of energy was calculated for each EEG sub-band. Finally, 46 features, as the mean energy of frequency bands between 4 and 50 Hz, containing 689 instances - for each subject -were collected in order to classify the emotional states. Our experimental results show that EEG dynamics induced by horror and relaxing movies can be classified with average classification rate of 92% using support vector machine (SVM) classifier. We also compared the performance of SVM to K-nearest neighbors (K-NN). The results show that K-NN achieves a better classification rate by 94% accuracy. The findings of this work are expected to pave the way to a new horizon in neuroscience by proving the point that only single-channel EEG data carry enough information for emotion classification.

  9. Nonlinear analysis of EEG signals at different mental states

    OpenAIRE

    Natarajan, Kannathal; Acharya U, Rajendra; Alias, Fadhilah; Tiboleng, Thelma; Puthusserypady, Sadasivan K

    2004-01-01

    Abstract Background The EEG (Electroencephalogram) is a representative signal containing information about the condition of the brain. The shape of the wave may contain useful information about the state of the brain. However, the human observer can not directly monitor these subtle details. Besides, since bio-signals are highly subjective, the symptoms may appear at random in the time scale. Therefore, the EEG signal parameters, extracted and analyzed using computers, are highly useful in di...

  10. Measurement and modification of the EEG and related behavior

    Science.gov (United States)

    Sterman, M. B.

    1991-01-01

    Electrophysiological changes in the sensorimotor pathways were found to accompany the effect of rhythmic EEG patterns in the sensorimotor cortex. Additionally, several striking behavioral changes were seen, including in particular an enhancement of sleep and an elevation of seizure threshold to epileptogenic agents. This raised the possibility that human seizure disorders might be influenced therapeutically by similar training. Our objective in human EEG feedback training became not only the facilitation of normal rhythmic patterns, but also the suppression of abnormal activity, thus requiring complex contingencies directed to the normalization of the sensorimotor EEG. To achieve this, a multicomponent frequency analysis was developed to extract and separate normal and abnormal elements of the EEG signal. Each of these elements was transduced to a specific component of a visual display system, and these were combined through logic circuits to present the subject with a symbolic display. Variable criteria provided for the gradual shaping of EEG elements towards the desired normal pattern. Some 50-70% of patients with poorly controlled seizure disorders experienced therapeutic benefits from this approach in our laboratory, and subsequently in many others. A more recent application of this approach to the modification of human brain function in our lab has been directed to the dichotomous problems of task overload and underload in the contemporary aviation environment. At least 70% of all aviation accidents have been attributed to the impact of these kinds of problems on crew performance. The use of EEG in this context has required many technical innovations and the application of the latest advances in EEG signal analysis. Our first goal has been the identification of relevant EEG characteristics. Additionally, we have developed a portable recording and analysis system for application in this context. Findings from laboratory and in-flight studies suggest that we

  11. EEG biofeedback improves attentional bias in high trait anxiety individuals

    OpenAIRE

    Wang, Sheng; Zhao, Yan; Chen, Sijuan; Lin, Guiping; Sun, Peng; Wang, Tinghuai

    2013-01-01

    Background Emotion-related attentional bias is implicated in the aetiology and maintenance of anxiety disorders. Electroencephalogram (EEG) biofeedback can obviously improve the anxiety disorders and reduce stress level, and can also enhance attention performance in healthy subjects. The present study examined the effects and mechanisms of EEG biofeedback training on the attentional bias of high trait anxiety (HTA) individuals toward negative stimuli. Results Event-related potentials were rec...

  12. Behavioral and EEG Correlates of Reduced Executive Functioning in Adolescents

    OpenAIRE

    Espano, Joshua

    2013-01-01

    Exposure to orphanage care or other deprived conditions represent a contributing risk factor in the development of ADHD behaviors. Upon leaving these contexts, the resting EEG patterns found in post-institutionalized (PI) children resemble the EEG profile of children with behavior problems, such as inattention, hyperactivity, and impulsivity. Specifically, this atypical pattern consists of increased theta power relative to other power spectra and decreased alpha power. This study examined if ...

  13. Seizure semiology and EEG findings in mitochondrial diseases.

    Science.gov (United States)

    Chevallier, Justyna A; Von Allmen, Gretchen K; Koenig, Mary Kay

    2014-05-01

    Seizures constitute a frequent yet under-described manifestation of mitochondrial disorders (MDs). The aim of this study was to describe electroencephalography (EEG) findings and clinical seizure types in a population of children and adults with mitochondrial disease. Retrospective chart review of 165 records of children and adults with mitochondrial disease seen in the University of Texas Houston Mitochondrial Center between 2007 and 2012 was performed; all subjects were diagnosed with confirmed mitochondrial disease. EEG findings and clinical data, including seizure semiology and response to antiepileptic drugs (AEDs), were analyzed and categorized. Sixty-six percent (109/165) of subjects had a routine EEG performed. Sixty-one percent (67/109) of EEG studies were abnormal and 85% (56/67) had epileptiform discharges. The most common EEG finding was generalized slowing (40/67, 60%). The most frequent category of epileptiform activity seen was multifocal discharges (41%), followed by focal (39%) and generalized (39%) discharges. Clinical seizures were seen in 55% of subjects and the most common types of seizures observed were complex partial (37%) and generalized tonic-clonic (GTC; 37%). The most common seizure type in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) was GTC (33%), with generalized or focal discharges seen on EEG. In Leigh syndrome GTC (11%) and complex partial (11%) seizures were the most frequent types. Of 60 subjects with clinical seizures, 28% were intractable to medical treatment. Mitochondrial disorder should be included in the list of differential diagnosis in any child that presents with encephalopathy, seizures, and a fluctuating clinical course. Given the relatively high prevalence of EEG abnormalities in patients with MD, EEG should be performed during initial evaluation in all patients with MD, not only upon clinical suspicion of epilepsy. Wiley Periodicals, Inc. © 2014 International

  14. Linear dynamic models for classification of single-trial EEG.

    Science.gov (United States)

    Samdin, S Balqis; Ting, Chee-Ming; Salleh, Sh-Hussain; Ariff, A K; Mohd Noor, A B

    2013-01-01

    This paper investigates the use of linear dynamic models (LDMs) to improve classification of single-trial EEG signals. Existing dynamic classification of EEG uses discrete-state hidden Markov models (HMMs) based on piecewise-stationary assumption, which is inadequate for modeling the highly non-stationary dynamics underlying EEG. The continuous hidden states of LDMs could better describe this continuously changing characteristic of EEG, and thus improve the classification performance. We consider two examples of LDM: a simple local level model (LLM) and a time-varying autoregressive (TVAR) state-space model. AR parameters and band power are used as features. Parameter estimation of the LDMs is performed by using expectation-maximization (EM) algorithm. We also investigate different covariance modeling of Gaussian noises in LDMs for EEG classification. The experimental results on two-class motor-imagery classification show that both types of LDMs outperform the HMM baseline, with the best relative accuracy improvement of 14.8% by LLM with full covariance for Gaussian noises. It may due to that LDMs offer more flexibility in fitting the underlying dynamics of EEG.

  15. Headache in the paediatrics patients, clinical-EEG Correlation.

    Directory of Open Access Journals (Sweden)

    Marcelino Lizano Rabelo

    2011-12-01

    Full Text Available A descriptive study was made, with the objective to describe to a clinical group of variables epidemiologists and of laboratory of 108 patients to whom it was made to them and EEG and whose fundamental symptom was the headache; in the period January to December of 2009. The data was taken from the registry of patients of the neurophysiology department of Paediatric Hospital. The variables of the study were: age, sex, type of headache, results of the EEG, and characteristics of pathological EEG activity. The results were expressed in graphical and analyzed tables and of percentage form. The patients of 14 to 16 years predominated (40,7%, female patient (53,7%, clinically the observed recurrent acute migraine in 60 cases was the one that prevailed, as well as normality in the EEG (81,5%, the pathological cases we observed focal paroxysms in 15 patients (75% and focal alterations in 80% of the pathological EEG. Conclusions: In our environment the migraine in the paediatric patient is a frequent pathology that motivates the accomplishment of diverse studies among them the EEG, being this normal one in most of the cases and the non-specific alterations, the recurrent acute migraine and female patients prevailed.

  16. Categorisation of Mobile EEG: A Researcher’s Perspective

    Directory of Open Access Journals (Sweden)

    Anthony D. Bateson

    2017-01-01

    Full Text Available Researchers are increasingly attempting to undertake electroencephalography (EEG recordings in novel environments and contexts outside of the traditional static laboratory setting. The term “mobile EEG,” although commonly used to describe many of these undertakings, is ambiguous, since it attempts to encompass a wide range of EEG device mobility, participant mobility, and system specifications used across investigations. To provide quantitative parameters for “mobile EEG,” we developed a Categorisation of Mobile EEG (CoME scheme based upon scoring of device mobility (D, from 0, off-body, to 5, head-mounted with no additional equipment, participant mobility (P, from 0, static, to 5, unconstrained running, system specification (S, from 4, lowest, to 20, highest, and number of channels (C used. The CoME scheme was applied to twenty-nine published mobile EEG studies. Device mobility scores ranged from 0D to 4D, participant mobility scores from 0P to 4P, and system specification scores from 6S to 17S. The format of the scores for the four parameters is given, for example, as (2D, 4P, 17S, 32C and readily enables comparisons across studies. Our CoME scheme enables researchers to quantify the degree of device mobility, participant mobility, and system specification used in their “mobile EEG” investigations in a standardised way.

  17. A three domain covariance framework for EEG/MEG data.

    Science.gov (United States)

    Roś, Beata P; Bijma, Fetsje; de Gunst, Mathisca C M; de Munck, Jan C

    2015-10-01

    In this paper we introduce a covariance framework for the analysis of single subject EEG and MEG data that takes into account observed temporal stationarity on small time scales and trial-to-trial variations. We formulate a model for the covariance matrix, which is a Kronecker product of three components that correspond to space, time and epochs/trials, and consider maximum likelihood estimation of the unknown parameter values. An iterative algorithm that finds approximations of the maximum likelihood estimates is proposed. Our covariance model is applicable in a variety of cases where spontaneous EEG or MEG acts as source of noise and realistic noise covariance estimates are needed, such as in evoked activity studies, or where the properties of spontaneous EEG or MEG are themselves the topic of interest, like in combined EEG-fMRI experiments in which the correlation between EEG and fMRI signals is investigated. We use a simulation study to assess the performance of the estimator and investigate the influence of different assumptions about the covariance factors on the estimated covariance matrix and on its components. We apply our method to real EEG and MEG data sets. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Artifact removal from EEG signals using adaptive filters in cascade

    International Nuclear Information System (INIS)

    Garces Correa, A; Laciar, E; Patino, H D; Valentinuzzi, M E

    2007-01-01

    Artifacts in EEG (electroencephalogram) records are caused by various factors, like line interference, EOG (electro-oculogram) and ECG (electrocardiogram). These noise sources increase the difficulty in analyzing the EEG and to obtaining clinical information. For this reason, it is necessary to design specific filters to decrease such artifacts in EEG records. In this paper, a cascade of three adaptive filters based on a least mean squares (LMS) algorithm is proposed. The first one eliminates line interference, the second adaptive filter removes the ECG artifacts and the last one cancels EOG spikes. Each stage uses a finite impulse response (FIR) filter, which adjusts its coefficients to produce an output similar to the artifacts present in the EEG. The proposed cascade adaptive filter was tested in five real EEG records acquired in polysomnographic studies. In all cases, line-frequency, ECG and EOG artifacts were attenuated. It is concluded that the proposed filter reduces the common artifacts present in EEG signals without removing significant information embedded in these records

  19. Predicting EEG complexity from sleep macro and microstructure

    International Nuclear Information System (INIS)

    Chouvarda, I; Maglaveras, N; Mendez, M O; Rosso, V; Parrino, L; Grassi, A; Terzano, M; Bianchi, A M; Cerutti, S

    2011-01-01

    This work investigates the relation between the complexity of electroencephalography (EEG) signal, as measured by fractal dimension (FD), and normal sleep structure in terms of its macrostructure and microstructure. Sleep features are defined, encoding sleep stage and cyclic alternating pattern (CAP) related information, both in short and long term. The relevance of each sleep feature to the EEG FD is investigated, and the most informative ones are depicted. In order to quantitatively assess the relation between sleep characteristics and EEG dynamics, a modeling approach is proposed which employs subsets of the sleep macrostructure and microstructure features as input variables and predicts EEG FD based on these features of sleep micro/macrostructure. Different sleep feature sets are investigated along with linear and nonlinear models. Findings suggest that the EEG FD time series is best predicted by a nonlinear support vector machine (SVM) model, employing both sleep stage/transitions and CAP features at different time scales depending on the EEG activation subtype. This combination of features suggests that short-term and long-term history of macro and micro sleep events interact in a complex manner toward generating the dynamics of sleep

  20. Rapidly Learned Identification of Epileptic Seizures from Sonified EEG

    Directory of Open Access Journals (Sweden)

    Psyche eLoui

    2014-10-01

    Full Text Available Sonification refers to a process by which data are converted into sound, providing an auditory alternative to visual display. Currently, the prevalent method for diagnosing seizures in epilepsy is by visually reading a patient’s electroencephalogram (EEG. However, sonification of the EEG data provides certain advantages due to the nature of human auditory perception. We hypothesized that human listeners will be able to identify seizures from EEGs using the auditory modality alone, and that accuracy of seizure identification will increase after a short training session. Here we describe an algorithm we have used to sonify EEGs of both seizure and non-seizure activity, followed by a training study in which subjects listened to short clips of sonified EEGs and determine whether each clip was of seizure or normal activity, both before and after a short training session. Results show that before training subjects performed at chance level in differentiating seizures vs. non-seizures, but there was a significant improvement of accuracy after the training session. After training, subjects successfully distinguished seizures from non-seizures using the auditory modality alone. Further analyses using signal detection theory demonstrated improvement in sensitivity and reduction in response bias as a result of training. This study demonstrates the potential of sonified EEGs to be used for the detection of seizures. Future studies will attempt to increase accuracy using novel training and sonification modifications, with the goals of managing, predicting, and ultimately controlling seizures using sonification as a possible biofeedback-based intervention for epilepsy.

  1. Corrected Four-Sphere Head Model for EEG Signals

    Directory of Open Access Journals (Sweden)

    Solveig Næss

    2017-10-01

    Full Text Available The EEG signal is generated by electrical brain cell activity, often described in terms of current dipoles. By applying EEG forward models we can compute the contribution from such dipoles to the electrical potential recorded by EEG electrodes. Forward models are key both for generating understanding and intuition about the neural origin of EEG signals as well as inverse modeling, i.e., the estimation of the underlying dipole sources from recorded EEG signals. Different models of varying complexity and biological detail are used in the field. One such analytical model is the four-sphere model which assumes a four-layered spherical head where the layers represent brain tissue, cerebrospinal fluid (CSF, skull, and scalp, respectively. While conceptually clear, the mathematical expression for the electric potentials in the four-sphere model is cumbersome, and we observed that the formulas presented in the literature contain errors. Here, we derive and present the correct analytical formulas with a detailed derivation. A useful application of the analytical four-sphere model is that it can serve as ground truth to test the accuracy of numerical schemes such as the Finite Element Method (FEM. We performed FEM simulations of the four-sphere head model and showed that they were consistent with the corrected analytical formulas. For future reference we provide scripts for computing EEG potentials with the four-sphere model, both by means of the correct analytical formulas and numerical FEM simulations.

  2. Methodological aspects of EEG and Body dynamics measurements during motion.

    Directory of Open Access Journals (Sweden)

    Pedro eReis

    2014-03-01

    Full Text Available EEG involves recording, analysis, and interpretation of voltages recorded on the human scalp originating from brain grey matter. EEG is one of the favorite methods to study and understand processes that underlie behavior. This is so, because EEG is relatively cheap, easy to wear, light weight and has high temporal resolution. In terms of behavior, this encompasses actions, such as movements, that are performed in response to the environment. However, there are methodological difficulties when recording EEG during movement such as movement artifacts. Thus, most studies about the human brain have examined activations during static conditions. This article attempts to compile and describe relevant methodological solutions that emerged in order to measure body and brain dynamics during motion. These descriptions cover suggestions of how to avoid and reduce motion artifacts, hardware, software and techniques for synchronously recording EEG, EMG, kinematics, kinetics and eye movements during motion. Additionally, we present various recording systems, EEG electrodes, caps and methods for determination of real/custom electrode positions. In the end we will conclude that it is possible to record and analyze synchronized brain and body dynamics related to movement or exercise tasks.

  3. Synchronizing MIDI and wireless EEG measurements during natural piano performance.

    Science.gov (United States)

    Zamm, Anna; Palmer, Caroline; Bauer, Anna-Katharina R; Bleichner, Martin G; Demos, Alexander P; Debener, Stefan

    2017-07-08

    Although music performance has been widely studied in the behavioural sciences, less work has addressed the underlying neural mechanisms, perhaps due to technical difficulties in acquiring high-quality neural data during tasks requiring natural motion. The advent of wireless electroencephalography (EEG) presents a solution to this problem by allowing for neural measurement with minimal motion artefacts. In the current study, we provide the first validation of a mobile wireless EEG system for capturing the neural dynamics associated with piano performance. First, we propose a novel method for synchronously recording music performance and wireless mobile EEG. Second, we provide results of several timing tests that characterize the timing accuracy of our system. Finally, we report EEG time domain and frequency domain results from N=40 pianists demonstrating that wireless EEG data capture the unique temporal signatures of musicians' performances with fine-grained precision and accuracy. Taken together, we demonstrate that mobile wireless EEG can be used to measure the neural dynamics of piano performance with minimal motion constraints. This opens many new possibilities for investigating the brain mechanisms underlying music performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Generalized Information Equilibrium Approaches to EEG Sleep Stage Discrimination

    Directory of Open Access Journals (Sweden)

    Todd Zorick

    2016-01-01

    Full Text Available Recent advances in neuroscience have raised the hypothesis that the underlying pattern of neuronal activation which results in electroencephalography (EEG signals is via power-law distributed neuronal avalanches, while EEG signals are nonstationary. Therefore, spectral analysis of EEG may miss many properties inherent in such signals. A complete understanding of such dynamical systems requires knowledge of the underlying nonequilibrium thermodynamics. In recent work by Fielitz and Borchardt (2011, 2014, the concept of information equilibrium (IE in information transfer processes has successfully characterized many different systems far from thermodynamic equilibrium. We utilized a publicly available database of polysomnogram EEG data from fourteen subjects with eight different one-minute tracings of sleep stage 2 and waking and an overlapping set of eleven subjects with eight different one-minute tracings of sleep stage 3. We applied principles of IE to model EEG as a system that transfers (equilibrates information from the time domain to scalp-recorded voltages. We find that waking consciousness is readily distinguished from sleep stages 2 and 3 by several differences in mean information transfer constants. Principles of IE applied to EEG may therefore prove to be useful in the study of changes in brain function more generally.

  5. Added clinical value of the inferior temporal EEG electrode chain.

    Science.gov (United States)

    Bach Justesen, Anders; Eskelund Johansen, Ann Berit; Martinussen, Noomi Ida; Wasserman, Danielle; Terney, Daniella; Meritam, Pirgit; Gardella, Elena; Beniczky, Sándor

    2018-01-01

    To investigate the diagnostic added value of supplementing the 10-20 EEG array with six electrodes in the inferior temporal chain. EEGs were recorded with 25 electrodes: 19 positions of the 10-20 system, and six additional electrodes in the inferior temporal chain (F9/10, T9/10, P9/10). Five-hundred consecutive standard and sleep EEG recordings were reviewed using the 10-20 array and the extended array. We identified the recordings with EEG abnormalities that had peak negativities at the inferior temporal electrodes, and those that only were visible at the inferior temporal electrodes. From the 286 abnormal recordings, the peak negativity was at the inferior temporal electrodes in 81 cases (28.3%) and only visible at the inferior temporal electrodes in eight cases (2.8%). In the sub-group of patients with temporal abnormalities (n = 134), these represented 59% (peak in the inferior chain) and 6% (only seen at the inferior chain). Adding six electrodes in the inferior temporal electrode chain to the 10-20 array improves the localization and identification of EEG abnormalities, especially those located in the temporal region. Our results suggest that inferior temporal electrodes should be added to the EEG array, to increase the diagnostic yield of the recordings. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  6. First seizure: EEG and neuroimaging following an epileptic seizure.

    Science.gov (United States)

    Pohlmann-Eden, Bernd; Newton, Mark

    2008-01-01

    An early EEG (within 48 h) and high-resolution magnetic resonance imaging (hr_MRI) are the methods of choice for an accurate diagnosis after a first seizure presentation. Together with a careful history and examination, they will allow definition of the epilepsy syndrome in two-thirds of patients and help assess the individual risk for seizure recurrence, which is determined by the specific syndrome and is highest with focal epileptiform activity on EEG. Despite the heterogeneity of first seizure studies, EEG and etiology are consistently found to be the best predictors for seizure recurrence and prognosis. The additional yield of sleep-deprived EEG and sleep EEG is uncertain; yet MRI is essential for detecting brain tumors and other structural bases for new epilepsy. The rate occurrence of remote symptomatic seizures increases significantly with age and the most common etiology in the elderly with a first seizure is stroke; however, its exact relevance to epileptogenicity is yet to be defined. There is a striking lack of systematic studies using early EEG and hr_MRI in order to better characterize epileptogenic areas and elucidate the mechanisms of seizure provocation.

  7. Bluetooth Communication Interface for EEG Signal Recording in Hyperbaric Chambers.

    Science.gov (United States)

    Pastena, Lucio; Formaggio, Emanuela; Faralli, Fabio; Melucci, Massimo; Rossi, Marco; Gagliardi, Riccardo; Ricciardi, Lucio; Storti, Silvia F

    2015-07-01

    Recording biological signals inside a hyperbaric chamber poses technical challenges (the steel walls enclosing it greatly attenuate or completely block the signals as in a Faraday cage), practical (lengthy cables creating eddy currents), and safety (sparks hazard from power supply to the electronic apparatus inside the chamber) which can be overcome with new wireless technologies. In this technical report we present the design and implementation of a Bluetooth system for electroencephalographic (EEG) recording inside a hyperbaric chamber and describe the feasibility of EEG signal transmission outside the chamber. Differently from older systems, this technology allows the online recording of amplified signals, without interference from eddy currents. In an application of this technology, we measured EEG activity in professional divers under three experimental conditions in a hyperbaric chamber to determine how oxygen, assumed at a constant hyperbaric pressure of 2.8 ATA , affects the bioelectrical activity. The EEG spectral power estimated by fast Fourier transform and the cortical sources of the EEG rhythms estimated by low-resolution brain electromagnetic analysis were analyzed in three different EEG acquisitions: breathing air at sea level; breathing oxygen at a simulated depth of 18 msw, and breathing air at sea level after decompression.

  8. Do sleep-deprived EEG recordings reflect spike index as found in full-night EEG recordings?

    Science.gov (United States)

    Larsson, Pål G; Evsiukova, Tatiana; Brockmeier, Frans; Ramm-Pettersen, Anette; Eeg-Olofsson, Orvar

    2010-11-01

    The sleep EEGs of many children with neurodevelopmental disorders reveal epileptiform activity. The aim of this study was to compare spike index (SI) in full-night recordings with SI in sleep-deprived EEGs in the morning; EEGs were obtained over 24 hours using ambulatory equipment. Sixteen children between the ages of 7 and 12 years were included in the study. They had to wake up at 3:00 AM and go to sleep again at 7:30 AM. Epileptiform activity was quantified, and SIs of full-night and morning recordings were compared. Two patients did not fall asleep. In one recording there was a technical problem that made calculations impossible. SIs calculated from EEGs obtained during a short nap in the morning were comparable to those calculated from full-night recordings. There seems to be a higher failure rate during morning recordings because of patients not falling asleep. Copyright © 2010 Elsevier Inc. All rights reserved.

  9. Granger Causality Analysis of Interictal iEEG Predicts Seizure Focus and Ultimate Resection.

    Science.gov (United States)

    Park, Eun-Hyoung; Madsen, Joseph R

    2018-01-01

    A critical conceptual step in epilepsy surgery is to locate the causal region of seizures. In practice, the causal region may be inferred from the set of electrodes showing early ictal activity. There would be advantages in deriving information about causal regions from interictal data as well. We applied Granger's statistical approach to baseline interictal data to calculate causal interactions. We hypothesized that maps of the Granger causality network (or GC maps) from interictal data might inform about the seizure network, and set out to see if "causality" in the Granger sense correlated with surgical targets. To determine whether interictal baseline data could produce GC maps, and whether the regions of high GC would statistically resemble the topography of the ictally active electrode (IAE) set and resection. Twenty-minute interictal baselines obtained from 25 consecutive patients were analyzed. The "GC maps" were quantitatively compared to conventionally constructed surgical plans, by using rank order and Cartesian distance statistics. In 16 of 25 cases, the interictal GC rankings of the electrodes in the IAE set were lower than predicted by chance (P aggregate probability of such a match by chance alone is very small (P < 10-20) suggesting that interictal GC maps correlated with ictal networks. The distance of the highest GC electrode to the IAE set and to the resection averaged 4 and 6 mm (Wilcoxon P < .001). GC analysis has the potential to help localize ictal networks from interictal data. © Congress of Neurological Surgeons 2017.

  10. Safety and EEG data quality of concurrent high-density EEG and high-speed fMRI at 3 Tesla.

    Directory of Open Access Journals (Sweden)

    Mette Thrane Foged

    Full Text Available Concurrent EEG and fMRI is increasingly used to characterize the spatial-temporal dynamics of brain activity. However, most studies to date have been limited to conventional echo-planar imaging (EPI. There is considerable interest in integrating recently developed high-speed fMRI methods with high-density EEG to increase temporal resolution and sensitivity for task-based and resting state fMRI, and for detecting interictal spikes in epilepsy. In the present study using concurrent high-density EEG and recently developed high-speed fMRI methods, we investigate safety of radiofrequency (RF related heating, the effect of EEG on cortical signal-to-noise ratio (SNR in fMRI, and assess EEG data quality.The study compared EPI, multi-echo EPI, multi-band EPI and multi-slab echo-volumar imaging pulse sequences, using clinical 3 Tesla MR scanners from two different vendors that were equipped with 64- and 256-channel MR-compatible EEG systems, respectively, and receive only array head coils. Data were collected in 11 healthy controls (3 males, age range 18-70 years and 13 patients with epilepsy (8 males, age range 21-67 years. Three of the healthy controls were scanned with the 256-channel EEG system, the other subjects were scanned with the 64-channel EEG system. Scalp surface temperature, SNR in occipital cortex and head movement were measured with and without the EEG cap. The degree of artifacts and the ability to identify background activity was assessed by visual analysis by a trained expert in the 64 channel EEG data (7 healthy controls, 13 patients.RF induced heating at the surface of the EEG electrodes during a 30-minute scan period with stable temperature prior to scanning did not exceed 1.0° C with either EEG system and any of the pulse sequences used in this study. There was no significant decrease in cortical SNR due to the presence of the EEG cap (p > 0.05. No significant differences in the visually analyzed EEG data quality were found between

  11. Dealing with noise and physiological artifacts in human EEG recordings: empirical mode methods

    Science.gov (United States)

    Runnova, Anastasiya E.; Grubov, Vadim V.; Khramova, Marina V.; Hramov, Alexander E.

    2017-04-01

    In the paper we propose the new method for removing noise and physiological artifacts in human EEG recordings based on empirical mode decomposition (Hilbert-Huang transform). As physiological artifacts we consider specific oscillatory patterns that cause problems during EEG analysis and can be detected with additional signals recorded simultaneously with EEG (ECG, EMG, EOG, etc.) We introduce the algorithm of the proposed method with steps including empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing these empirical modes and reconstructing of initial EEG signal. We show the efficiency of the method on the example of filtration of human EEG signal from eye-moving artifacts.

  12. Multimodal EEG Recordings, Psychometrics and Behavioural Analysis.

    Science.gov (United States)

    Boeijinga, Peter H

    2015-01-01

    High spatial and temporal resolution measurements of neuronal activity are preferably combined. In an overview on how this approach can take shape, multimodal electroencephalography (EEG) is treated in 2 main parts: by experiments without a task and in the experimentally cued working brain. It concentrates first on the alpha rhythm properties and next on data-driven search for patterns such as the default mode network. The high-resolution volumic distributions of neuronal metabolic indices result in distributed cortical regions and possibly relate to numerous nuclei, observable in a non-invasive manner in the central nervous system of humans. The second part deals with paradigms in which nowadays assessment of target-related networks can align level-dependent blood oxygenation, electrical responses and behaviour, taking the temporal resolution advantages of event-related potentials. Evidence-based electrical propagation in serial tasks during performance is now to a large extent attributed to interconnected pathways, particularly chronometry-dependent ones, throughout a chain including a dorsal stream, next ventral cortical areas taking the flow of information towards inferior temporal domains. The influence of aging is documented, and results of the first multimodal studies in neuropharmacology are consistent. Finally a scope on implementation of advanced clinical applications and personalized marker strategies in neuropsychiatry is indicated. © 2016 S. Karger AG, Basel.

  13. Dipole localization using simulated intracerebral EEG.

    Science.gov (United States)

    Chang, Nathalie; Gulrajani, Ramesh; Gotman, Jean

    2005-11-01

    In the clinical interpretation of intracerebral EEGs, epileptic foci are commonly identified by visually analyzing the amplitude of the potentials. This is potentially misleading since electrodes record activity from several sources, but the nearest ones generate large amplitudes that can overpower distant sources. Our objective was to improve foci detection in intracerebral recordings by applying source localization methods. Data were simulated by placing 3 sources in a semi-infinite medium near 3 intracerebral electrodes. Potentials were generated and contaminated with white and correlated noise. Two inverse problem algorithms, beamforming and RAP-MUSIC, were used to calculate equivalent dipoles. Simulations for each noise types showed that the two methods detected the source locations accurately, with RAP-MUSIC reporting lower orientation errors. With correlated noise, beamforming reconstructed original source waveforms poorly. A spatial resolution analysis was performed, in which beamforming adequately distinguished sources separated by 1.2 cm, whereas RAP-MUSIC separated sources as close as 0.4-0.6 cm. Both source localization methods proved useful in detecting the location of dipolar sources based on simulated intracerebral potentials. For all simulations, RAP-MUSIC was more accurate than beamforming. It is possible to use source localization methods traditionally applied to scalp recordings for improving source detection from intracerebral recordings.

  14. Monitoring alert and drowsy states by modeling EEG source nonstationarity

    Science.gov (United States)

    Hsu, Sheng-Hsiou; Jung, Tzyy-Ping

    2017-10-01

    Objective. As a human brain performs various cognitive functions within ever-changing environments, states of the brain characterized by recorded brain activities such as electroencephalogram (EEG) are inevitably nonstationary. The challenges of analyzing the nonstationary EEG signals include finding neurocognitive sources that underlie different brain states and using EEG data to quantitatively assess the state changes. Approach. This study hypothesizes that brain activities under different states, e.g. levels of alertness, can be modeled as distinct compositions of statistically independent sources using independent component analysis (ICA). This study presents a framework to quantitatively assess the EEG source nonstationarity and estimate levels of alertness. The framework was tested against EEG data collected from 10 subjects performing a sustained-attention task in a driving simulator. Main results. Empirical results illustrate that EEG signals under alert versus drowsy states, indexed by reaction speeds to driving challenges, can be characterized by distinct ICA models. By quantifying the goodness-of-fit of each ICA model to the EEG data using the model deviation index (MDI), we found that MDIs were significantly correlated with the reaction speeds (r  =  ‑0.390 with alertness models and r  =  0.449 with drowsiness models) and the opposite correlations indicated that the two models accounted for sources in the alert and drowsy states, respectively. Based on the observed source nonstationarity, this study also proposes an online framework using a subject-specific ICA model trained with an initial (alert) state to track the level of alertness. For classification of alert against drowsy states, the proposed online framework achieved an averaged area-under-curve of 0.745 and compared favorably with a classic power-based approach. Significance. This ICA-based framework provides a new way to study changes of brain states and can be applied to

  15. EEG responses to visual landmarks in flying pigeons.

    Science.gov (United States)

    Vyssotski, Alexei L; Dell'Omo, Giacomo; Dell'Ariccia, Gaia; Abramchuk, Andrei N; Serkov, Andrei N; Latanov, Alexander V; Loizzo, Alberto; Wolfer, David P; Lipp, Hans-Peter

    2009-07-28

    GPS analysis of flight trajectories of pigeons can reveal that topographic features influence their flight paths. Recording electrical brain activity that reflects attentional processing could indicate objects of interest that do not cause changes in the flight path. Therefore, we investigated whether crossing particular visual landmarks when homing from a familiar release site is associated with changes in EEG. Birds carried both data-loggers for recording GPS position and EEG during flight. First, we classified characteristic EEG frequencies of caged birds and found five main bands: A: 0-3, B: 3-12, C: 12-60, D: 60-130, and E: 130-200 Hz. We analyzed changes in these activity bands when pigeons were released over sea (a featureless environment) and over land. Passing over the coastline and other prominent landmarks produced a pattern of EEG alterations consisting of two phases: activation of EEG in the high-frequency bands (D and/or E), followed by activation of C. Overlaying the EEG activity with GPS tracks allowed us to identify topographical features of interest for the pigeons that were not recognizable by distinct changes of their flight path. We provide evidence that EEG analysis can identify landmarks and objects of interest during homing. Middle-frequency activity (C) reflects visual perception of prominent landmarks, whereas activation of higher frequencies (D and E) is linked with information processing at a higher level. Activation of E bands is likely to reflect an initial process of orientation and is not necessarily linked with processing of visual information.

  16. Association of Electroencephalography (EEG) Power Spectra with Corneal Nerve Fiber Injury in Retinoblastoma Patients.

    Science.gov (United States)

    Liu, Jianliang; Sun, Juanjuan; Diao, Yumei; Deng, Aijun

    2016-09-04

    BACKGROUND In our clinical experience we discovered that EEG band power may be correlated with corneal nerve injury in retinoblastoma patients. This study aimed to investigate biomarkers obtained from electroencephalography (EEG) recordings to reflect corneal nerve injury in retinoblastoma patients. MATERIAL AND METHODS Our study included 20 retinoblastoma patients treated at the Department of Ophthalmology, Affiliated Hospital of Weifang Medical University between 2010 and 2014. Twenty normal individuals were included in the control group. EEG activity was recorded continuously with 32 electrodes using standard EEG electrode placement for detecting EEG power. A cornea confocal microscope was used to examine corneal nerve injury in retinoblastoma patients and normal individuals. Spearman rank correlation analysis was used to analyze the correlation between corneal nerve injury and EEG power changes. The sensitivity and specificity of changed EEG power in diagnosis of corneal nerve injury were also analyzed. RESULTS The predominantly slow EEG oscillations changed gradually into faster waves in retinoblastoma patients. The EEG pattern in retinoblastoma patients was characterized by a distinct increase of delta (Pretinoblastoma patients. Corneal nerve injury was positively correlated with delta EEG spectra power and negatively correlated with theta EEG spectra power. The diagnostic sensitivity and specificity by compounding in the series were 60% and 67%, respectively. CONCLUSIONS Changes in delta and theta of EEG appear to be associated with occurrence of corneal nerve injury. Useful information can be provided for evaluating corneal nerve damage in retinoblastoma patients through analyzing EEG power bands.

  17. A Novel Approach Based on Data Redundancy for Feature Extraction of EEG Signals.

    Science.gov (United States)

    Amin, Hafeez Ullah; Malik, Aamir Saeed; Kamel, Nidal; Hussain, Muhammad

    2016-03-01

    Feature extraction and classification for electroencephalogram (EEG) in medical applications is a challenging task. The EEG signals produce a huge amount of redundant data or repeating information. This redundancy causes potential hurdles in EEG analysis. Hence, we propose to use this redundant information of EEG as a feature to discriminate and classify different EEG datasets. In this study, we have proposed a JPEG2000 based approach for computing data redundancy from multi-channels EEG signals and have used the redundancy as a feature for classification of EEG signals by applying support vector machine, multi-layer perceptron and k-nearest neighbors classifiers. The approach is validated on three EEG datasets and achieved high accuracy rate (95-99 %) in the classification. Dataset-1 includes the EEG signals recorded during fluid intelligence test, dataset-2 consists of EEG signals recorded during memory recall test, and dataset-3 has epileptic seizure and non-seizure EEG. The findings demonstrate that the approach has the ability to extract robust feature and classify the EEG signals in various applications including clinical as well as normal EEG patterns.

  18. Textile electrodes for EEG recording--a pilot study.

    Science.gov (United States)

    Löfhede, Johan; Seoane, Fernando; Thordstein, Magnus

    2012-12-07

    The overall aim of our research is to develop a monitoring system for neonatal intensive care units. Long-term EEG monitoring in newborns require that the electrodes don't harm the sensitive skin of the baby, an especially relevant feature for premature babies. Our approach to EEG monitoring is based on several electrodes distributed over the head of the baby, and since the weight of the head always will be on some of them, any type of hard electrode will inevitably cause a pressure-point that can irritate the skin. Therefore, we propose the use of soft conductive textiles as EEG electrodes, primarily for neonates, but also for other kinds of unobtrusive long-term monitoring. In this paper we have tested two types of textile electrodes on five healthy adults and compared them to standard high quality electrodes. The acquired signals were compared with respect to morphology, frequency distribution, spectral coherence, correlation and power line interference sensitivity, and the signals were found to be similar in most respects. The good measurement performance exhibited by the textile electrodes indicates that they are feasible candidates for EEG recording, opening the door for long-term EEG monitoring applications.

  19. Textile Electrodes for EEG Recording — A Pilot Study

    Science.gov (United States)

    Löfhede, Johan; Seoane, Fernando; Thordstein, Magnus

    2012-01-01

    The overall aim of our research is to develop a monitoring system for neonatal intensive care units. Long-term EEG monitoring in newborns require that the electrodes don’t harm the sensitive skin of the baby, an especially relevant feature for premature babies. Our approach to EEG monitoring is based on several electrodes distributed over the head of the baby, and since the weight of the head always will be on some of them, any type of hard electrode will inevitably cause a pressure-point that can irritate the skin. Therefore, we propose the use of soft conductive textiles as EEG electrodes, primarily for neonates, but also for other kinds of unobtrusive long-term monitoring. In this paper we have tested two types of textile electrodes on five healthy adults and compared them to standard high quality electrodes. The acquired signals were compared with respect to morphology, frequency distribution, spectral coherence, correlation and power line interference sensitivity, and the signals were found to be similar in most respects. The good measurement performance exhibited by the textile electrodes indicates that they are feasible candidates for EEG recording, opening the door for long-term EEG monitoring applications. PMID:23223149

  20. Quantitative change of EEG and respiration signals during mindfulness meditation.

    Science.gov (United States)

    Ahani, Asieh; Wahbeh, Helane; Nezamfar, Hooman; Miller, Meghan; Erdogmus, Deniz; Oken, Barry

    2014-05-14

    This study investigates measures of mindfulness meditation (MM) as a mental practice, in which a resting but alert state of mind is maintained. A population of older people with high stress level participated in this study, while electroencephalographic (EEG) and respiration signals were recorded during a MM intervention. The physiological signals during meditation and control conditions were analyzed with signal processing. EEG and respiration data were collected and analyzed on 34 novice meditators after a 6-week meditation intervention. Collected data were analyzed with spectral analysis, phase analysis and classification to evaluate an objective marker for meditation. Different frequency bands showed differences in meditation and control conditions. Furthermore, we established a classifier using EEG and respiration signals with a higher accuracy (85%) at discriminating between meditation and control conditions than a classifier using the EEG signal only (78%). Support vector machine (SVM) classifier with EEG and respiration feature vector is a viable objective marker for meditation ability. This classifier should be able to quantify different levels of meditation depth and meditation experience in future studies.

  1. Spectral EEG Features of a Short Psycho-physiological Relaxation

    Directory of Open Access Journals (Sweden)

    Teplan Michal

    2014-08-01

    Full Text Available Short-lasting psycho-physiological relaxation was investigated through an analysis of its bipolar electroencephalographic (EEG characteristics. In 8 subjects, 6-channel EEG data of 3-minute duration were recorded during 88 relaxation sessions. Time course of spectral EEG features was examined. Alpha powers were decreasing during resting conditions of 3-minute sessions in lying position with eyes closed. This was followed by a decrease of total power in centro-parietal cortex regions and an increase of beta power in fronto-central areas. Represented by EEG coherences the interhemispheric communication between the parieto-occipital regions was enhanced within a frequency range of 2-10 Hz. In order to discern between higher and lower levels of relaxation distinguished according to self-rated satisfaction, EEG features were assessed and discriminating parameters were identified. Successful relaxation was determined mainly by the presence of decreased delta-1 power across the cortex. Potential applications for these findings include the clinical, pharmacological, and stress management fields.

  2. Decoding English Alphabet Letters Using EEG Phase Information

    Science.gov (United States)

    Wang, YiYan; Wang, Pingxiao; Yu, Yuguo

    2018-01-01

    Increasing evidence indicates that the phase pattern and power of the low frequency oscillations of brain electroencephalograms (EEG) contain significant information during the human cognition of sensory signals such as auditory and visual stimuli. Here, we investigate whether and how the letters of the alphabet can be directly decoded from EEG phase and power data. In addition, we investigate how different band oscillations contribute to the classification and determine the critical time periods. An English letter recognition task was assigned, and statistical analyses were conducted to decode the EEG signal corresponding to each letter visualized on a computer screen. We applied support vector machine (SVM) with gradient descent method to learn the potential features for classification. It was observed that the EEG phase signals have a higher decoding accuracy than the oscillation power information. Low-frequency theta and alpha oscillations have phase information with higher accuracy than do other bands. The decoding performance was best when the analysis period began from 180 to 380 ms after stimulus presentation, especially in the lateral occipital and posterior temporal scalp regions (PO7 and PO8). These results may provide a new approach for brain-computer interface techniques (BCI) and may deepen our understanding of EEG oscillations in cognition. PMID:29467615

  3. PHYSIOLOGIC PATTERNS OF SLEEP ON EEG, MASKING OF EPILEPTIFORM ACTIVITY

    Directory of Open Access Journals (Sweden)

    L. Yu. Glukhova

    2013-01-01

    Full Text Available Physiologic patterns of sleep on EEG can sometimes be similar to epileptiform activity and even to the EEG pattern of epileptic seizures, but they have no connection to epilepsy and their incorrect interpretation may lead to overdiagnosis of epilepsy. These sleep patterns include vertex transients, K-complexes, hypnagogic hypersynchrony, 14 and 6 Hz positive bursts, wicket-potentials, etc. The main distinctive features of acute physiological phenomena of sleep unlike epileptiform activity are stereotyped, monomorphic morphology of waves, which frequently has rhythmic, arcuate pattern, often with change of lateralization, mainly dominated in the first stages of sleep (N1-N2, with their reduction in the deeper stages and transition to delta sleep (N3. The correct interpretation of physiological sharp-wave phenomena of sleep on EEG requires considerable training and experience of the physician. Our review includes a variety of physiological sleep patterns, which can mimic epileptiform activity on EEG, their criteria of diagnostic with demonstration of own illustrations of EEG.

  4. The characteristics of EEG power spectra changes after ACL rupture.

    Directory of Open Access Journals (Sweden)

    Xin Miao

    Full Text Available Reestablishing knee stability is the core of the treatment of ACL (Anterior Cruciate Ligament injury. Some patients still have a feeling of instability of the knee after ACL injury treatment. This unstable feeling may be caused by central nervous system changes after ACL rupture.To identify the central changes after ACL rupture, EEG spectra were recorded to compare ACL patients and healthy controls when they were walking, jogging, and landing.There was a significant increase in delta, theta, alpha and beta band power during walking, jogging and landing in ACL patients. We also found an asymmetry phenomenon of EEG only in the ACL patients, mainly in the frontal area and central-parietal area. The asymmetry of beta band power extended to the frontal and the central area during jogging and landing task.There were significant differences in EEG power spectra between the ACL patients and healthy people. ACL patients showed high EEG band power activities and an asymmetry phenomenon. EEG power changes were affected by movements, the asymmetry extended when performing more complicated movements.

  5. Computerized spectral analyses of EEG in chronic schizophrenic patients

    International Nuclear Information System (INIS)

    Fujita, Haruhiro

    1985-01-01

    This study was aimed at clarifying the EEG difference between chronic schizophrenic patients and normal controls by using the EEG method of spectral analyses. Twelve comparatively homogenous chronic schizophrenic patients and the 10 healthy controls were subjected to EEG investigations. 1) The EEG of schizophrenic patients had a slowing tendency of the frequency in the frontal pole, anterior temporal and central regions of the scalp compared with control subjects. 2) There was a decrease of mutual relation among the five electrodes' peak frequency in the schizophrenic patients. 3) The EEG of schizophrenic patients had more fast waves of β 1 and β 2 band than that of control subjects. 4) A slowing tendency of the frequency in the first half regions of the scalp was not found in 3 chronic schizophrenic patients which showed defective functions in the frontal area by positron emission tomography. 5) When mental arithmetic was given, the schizophrenic patients showed an increase of fast wave in the central, posterior temporal and occipital regions of the scalp. 6) When they opened their eyes, attenuation in the α band was not so marked in the schizophrenic patients. (author)

  6. Frontal EEG Asymmetry of Mood: A Mini-Review

    Directory of Open Access Journals (Sweden)

    Massimiliano Palmiero

    2017-11-01

    Full Text Available The present mini-review was aimed at exploring the frontal EEG asymmetry of mood. With respect to emotion, interpreted as a discrete affective process, mood is more controllable, more nebulous, and more related to mind/cognition; in addition, causes are less well-defined than those eliciting emotion. Therefore, firstly, the rational for the distinction between emotion and mood was provided. Then, the main frontal EEG asymmetry models were presented, such as the motivational approach/withdrawal, valence/arousal, capability, and inhibition asymmetric models. Afterward, the frontal EEG asymmetry of mood was investigated following three research lines, that is considering studies involving different mood induction procedures, dispositional mood (positive and negative affect, and mood alterations in both healthy and clinical populations. In general, results were found to be contradictory, no model is unequivocally supported regardless the research line considered. Different methodological issues were raised, such as: the composition of samples used across studies, in particular, gender and age were found to be critical variables that should be better addressed in future studies; the importance of third variables that might mediate the relationship between frontal EEG asymmetries and mood, for example bodily states and hormonal responses; the role of cognition, namely the interplay between mood and executive functions. In light of these issues, future research directions were proposed. Amongst others, the need to explore the neural connectivity that underpins EEG asymmetries, and the need to include both positive and negative mood conditions in the experimental designs have been highlighted.

  7. Quantitative change of EEG and respiration signals during mindfulness meditation

    Science.gov (United States)

    2014-01-01

    Background This study investigates measures of mindfulness meditation (MM) as a mental practice, in which a resting but alert state of mind is maintained. A population of older people with high stress level participated in this study, while electroencephalographic (EEG) and respiration signals were recorded during a MM intervention. The physiological signals during meditation and control conditions were analyzed with signal processing. Methods EEG and respiration data were collected and analyzed on 34 novice meditators after a 6-week meditation intervention. Collected data were analyzed with spectral analysis, phase analysis and classification to evaluate an objective marker for meditation. Results Different frequency bands showed differences in meditation and control conditions. Furthermore, we established a classifier using EEG and respiration signals with a higher accuracy (85%) at discriminating between meditation and control conditions than a classifier using the EEG signal only (78%). Conclusion Support vector machine (SVM) classifier with EEG and respiration feature vector is a viable objective marker for meditation ability. This classifier should be able to quantify different levels of meditation depth and meditation experience in future studies. PMID:24939519

  8. Cortical sources of awake scalp EEG in eating disorders.

    Science.gov (United States)

    Rodriguez, Guido; Babiloni, Claudio; Brugnolo, Andrea; Del Percio, Claudio; Cerro, Fabrizio; Gabrielli, Filippo; Girtler, Nicola; Nobili, Flavio; Murialdo, Giovanni; Rossini, Paolo M; Rossi, Davide Sebastiano; Baruzzi, Chiara; Ferro, Antonio Maria

    2007-06-01

    To investigate quantitative EEG (qEEG) in anorexia nervosa (AN) and bulimia nervosa (BN) in comparison with healthy controls. Resting EEG was recorded in 30 healthy females (age: 27.1+/-5.5), 16-AN females (age: 26.4+/-9.5) and 12-BN females (age: 27.0+/-6.3). Cortical EEG sources (delta, theta, alpha 1, alpha 2, beta 1, beta 2) were modeled by LORETA solutions. The statistical analysis was performed considering the factors Group, power Band, and region of interest (central, frontal, parietal, occipital, temporal, limbic). Alpha 1 sources in central, parietal, occipital and limbic areas showed a greater amplitude in Controls versus AN and BN groups. Alpha 2 sources in parietal, occipital and limbic areas showed a greater amplitude in Controls than in both AN and BN groups. Alpha 1 sources in temporal area showed a greater amplitude in Controls compared to both the BN and AN groups as well as in the BN group compared to AN group. Central alpha 1 source correlated significantly with BMI in patients. These results support the hypothesis that eating disorders are related to altered mechanisms of cortical neural synchronization, especially in rolandic alpha rhythms. To our knowledge this is the first study by LORETA able to detect modifications of cortical EEG activity in eating disorders.

  9. Modulation of EEG Theta Band Signal Complexity by Music Therapy

    Science.gov (United States)

    Bhattacharya, Joydeep; Lee, Eun-Jeong

    The primary goal of this study was to investigate the impact of monochord (MC) sounds, a type of archaic sounds used in music therapy, on the neural complexity of EEG signals obtained from patients undergoing chemotherapy. The secondary goal was to compare the EEG signal complexity values for monochords with those for progressive muscle relaxation (PMR), an alternative therapy for relaxation. Forty cancer patients were randomly allocated to one of the two relaxation groups, MC and PMR, over a period of six months; continuous EEG signals were recorded during the first and last sessions. EEG signals were analyzed by applying signal mode complexity, a measure of complexity of neuronal oscillations. Across sessions, both groups showed a modulation of complexity of beta-2 band (20-29Hz) at midfrontal regions, but only MC group showed a modulation of complexity of theta band (3.5-7.5Hz) at posterior regions. Therefore, the neuronal complexity patterns showed different changes in EEG frequency band specific complexity resulting in two different types of interventions. Moreover, the different neural responses to listening to monochords and PMR were observed after regular relaxation interventions over a short time span.

  10. Nonlinear analysis of EEG signals at different mental states

    Directory of Open Access Journals (Sweden)

    Tiboleng Thelma

    2004-03-01

    Full Text Available Abstract Background The EEG (Electroencephalogram is a representative signal containing information about the condition of the brain. The shape of the wave may contain useful information about the state of the brain. However, the human observer can not directly monitor these subtle details. Besides, since bio-signals are highly subjective, the symptoms may appear at random in the time scale. Therefore, the EEG signal parameters, extracted and analyzed using computers, are highly useful in diagnostics. This work discusses the effect on the EEG signal due to music and reflexological stimulation. Methods In this work, nonlinear parameters like Correlation Dimension (CD, Largest Lyapunov Exponent (LLE, Hurst Exponent (H and Approximate Entropy (ApEn are evaluated from the EEG signals under different mental states. Results The results obtained show that EEG to become less complex relative to the normal state with a confidence level of more than 85% due to stimulation. Conclusions It is found that the measures are significantly lower when the subjects are under sound or reflexologic stimulation as compared to the normal state. The dimension increases with the degree of the cognitive activity. This suggests that when the subjects are under sound or reflexologic stimuli, the number of parallel functional processes active in the brain is less and the brain goes to a more relaxed state

  11. Nonlinear dimensionality reduction of electroencephalogram (EEG) for Brain Computer interfaces.

    Science.gov (United States)

    Teli, Mohammad Nayeem; Anderson, Charles

    2009-01-01

    Patterns in electroencephalogram (EEG) signals are analyzed for a Brain Computer Interface (BCI). An important aspect of this analysis is the work on transformations of high dimensional EEG data to low dimensional spaces in which we can classify the data according to mental tasks being performed. In this research we investigate how a Neural Network (NN) in an auto-encoder with bottleneck configuration can find such a transformation. We implemented two approximate second-order methods to optimize the weights of these networks, because the more common first-order methods are very slow to converge for networks like these with more than three layers of computational units. The resulting non-linear projections of time embedded EEG signals show interesting separations that are related to tasks. The bottleneck networks do indeed discover nonlinear transformations to low-dimensional spaces that capture much of the information present in EEG signals. However, the resulting low-dimensional representations do not improve classification rates beyond what is possible using Quadratic Discriminant Analysis (QDA) on the original time-lagged EEG.

  12. Brain oscillations in sport: toward EEG biomakers of performance

    Directory of Open Access Journals (Sweden)

    Guy eCheron

    2016-02-01

    Full Text Available Brain dynamics is at the basis of top performance accomplishment in sports. The search for neural biomarkers of performance remains a challenge in movement science and sport psychology. The noninvasive nature of high-density electroencephalography (EEG recording has made it a most promising avenue for providing quantitative feedback to practitioners and coaches. Here, we review the current relevance of the main types of EEG oscillations in order to trace a perspective for future practical applications of EEG and event-related potentials (ERP in sport. In this context, the hypotheses of unified brain rhythms and continuity between wake and sleep states should provide a functional template for EEG biomarkers in sport. The oscillations in the thalamo-cortical and hippocampal circuitry including the physiology of the place cells and the grid cells provide a frame of reference for the analysis of delta, theta, beta, alpha (incl.mu and gamma oscillations recorded in the space field of human performance. Based on recent neuronal models facilitating the distinction between the different dynamic regimes (selective gating and binding in these different oscillations we suggest an integrated approach articulating together the classical biomechanical factors (3D movements and EMG and the high-density EEG and ERP signals to allow finer mathematical analysis to optimize sport performance, such as microstates, coherency/directionality analysis and neural generators.

  13. EEG biofeedback improves attentional bias in high trait anxiety individuals.

    Science.gov (United States)

    Wang, Sheng; Zhao, Yan; Chen, Sijuan; Lin, Guiping; Sun, Peng; Wang, Tinghuai

    2013-10-07

    Emotion-related attentional bias is implicated in the aetiology and maintenance of anxiety disorders. Electroencephalogram (EEG) biofeedback can obviously improve the anxiety disorders and reduce stress level, and can also enhance attention performance in healthy subjects. The present study examined the effects and mechanisms of EEG biofeedback training on the attentional bias of high trait anxiety (HTA) individuals toward negative stimuli. Event-related potentials were recorded while HTA (n=24) and nonanxious (n=21) individuals performed the color-word emotional Stroop task. During the emotional Stroop task, HTA participants showed longer reaction times and P300 latencies induced by negative words, compared to nonanxious participants.The EEG biofeedback significantly decreased the trait anxiety inventory score and reaction time in naming the color of negative words in the HTA group. P300 latencies evoked by negative stimuli in the EEG biofeedback group were significantly reduced after the alpha training, while no significant changes were observed in the sham biofeedback group after the intervention. The prolonged P300 latency is associated with attentional bias to negative stimuli in the HTA group. EEG biofeedback training demonstrated a significant improvement of negative emotional attentional bias in HTA individuals, which may be due to the normalization of P300 latency.

  14. Textile Electrodes for EEG Recording — A Pilot Study

    Directory of Open Access Journals (Sweden)

    Johan Löfhede

    2012-12-01

    Full Text Available The overall aim of our research is to develop a monitoring system for neonatal intensive care units. Long-term EEG monitoring in newborns require that the electrodes don’t harm the sensitive skin of the baby, an especially relevant feature for premature babies. Our approach to EEG monitoring is based on several electrodes distributed over the head of the baby, and since the weight of the head always will be on some of them, any type of hard electrode will inevitably cause a pressure-point that can irritate the skin. Therefore, we propose the use of soft conductive textiles as EEG electrodes, primarily for neonates, but also for other kinds of unobtrusive long-term monitoring. In this paper we have tested two types of textile electrodes on five healthy adults and compared them to standard high quality electrodes. The acquired signals were compared with respect to morphology, frequency distribution, spectral coherence, correlation and power line interference sensitivity, and the signals were found to be similar in most respects. The good measurement performance exhibited by the textile electrodes indicates that they are feasible candidates for EEG recording, opening the door for long-term EEG monitoring applications.

  15. EEG changes in children born to epileptic parents

    Directory of Open Access Journals (Sweden)

    D. V. Morozov

    2015-01-01

    Full Text Available Epileptiform EEG changes are much more common in children whose parents are epileptic than in the population. There is evidence that subclinical epileptiform activity affects children’s intellect and behavior. These changes need timely detection and therapy. Objective: to determine the specific features and rates of EEG abnormalities in children born to parents with epilepsy. Patients and methods. The brain bioelectrical activity of 47 children born to epileptic fathers, 53 children born to epileptic mothers, and 46 children born to healthy parents (a control group was evaluated via video EEG monitoring method on an Encephalan 9 apparatus (Medicom MTD, Taganrog, Russia. Results and discussion. Epileptiform EEG activity was significantly more frequently recorded in the children born to epileptic patients than in the control children. There was no significant difference in the detection rate of epileptiform activity in the groups of children, whose parents had epilepsy. EEG changes were significantly more common in children whose parents had idiopathic generalized epilepsy. The children born to epileptic mothers were more often recorded to have impaired bioelectrical activity of organic nature as a regional continued deceleration of basic activity and its deceleration in the background recording. Epileptiform activity was subclinical in the majority of cases. At the same time, it was unaccompanied by clinical manifestations in all the control children. Regional epileptiform activity was predominant in the study and control groups. 

  16. Localised astroglial dysfunction disrupts high-frequency EEG rhythms.

    Science.gov (United States)

    Willoughby, J O; Mackenzie, L; Pope, K J; Broberg, M; Nilsson, M

    2005-02-01

    We used cerebral cortex injections of fluorocitrate to determine if selective astrocytic disturbances affect the electroencephalogram (EEG). Rats were halothane-anaesthetized and 0.8 nmol of sodium fluorocitrate was injected into hindlimb (motor-sensory) cortex. Extra-dural EEG electrodes were implanted after which the anaesthesia was ceased. EEG was recorded at 1, 3, 5, 7, 24 and 48 hours. There was a broad-band reduction in frequencies in the EEG between 20 and 100 Hz commencing within 1 hour of injection and largely restricted to the side of injection and to frontal cortex, and maximal at 3 hours. Halothane had a suppressive effect on gamma power after citrate injection, but also prevented EEG suppression caused by fluorocitrate, consistent with the hypothesis that some of the action of fluorocitrate depended on gap-junctions. The findings are consistent with the hypothesis that primary astroglial dysfunction leads to reduced neuronal transmission and further supports gap-junctions as mediating fluorocitrate-induced astroglial effects.

  17. EEG Differentiation Analysis and Stimulus Set Meaningfulness

    Directory of Open Access Journals (Sweden)

    Armand Mensen

    2017-10-01

    Full Text Available A set of images can be considered as meaningfully different for an observer if they can be distinguished phenomenally from one another. Each phenomenal difference must be supported by some neurophysiological differences. Differentiation analysis aims to quantify neurophysiological differentiation evoked by a given set of stimuli to assess its meaningfulness to the individual observer. As a proof of concept using high-density EEG, we show increased neurophysiological differentiation for a set of natural, meaningfully different images in contrast to another set of artificially generated, meaninglessly different images in nine participants. Stimulus-evoked neurophysiological differentiation (over 257 channels, 800 ms was systematically greater for meaningful vs. meaningless stimulus categories both at the group level and for individual subjects. Spatial breakdown showed a central-posterior peak of differentiation, consistent with the visual nature of the stimulus sets. Temporal breakdown revealed an early peak of differentiation around 110 ms, prominent in the central-posterior region; and a later, longer-lasting peak at 300–500 ms that was spatially more distributed. The early peak of differentiation was not accompanied by changes in mean ERP amplitude, whereas the later peak was associated with a higher amplitude ERP for meaningful images. An ERP component similar to visual-awareness-negativity occurred during the nadir of differentiation across all image types. Control stimulus sets and further analysis indicate that changes in neurophysiological differentiation between meaningful and meaningless stimulus sets could not be accounted for by spatial properties of the stimuli or by stimulus novelty and predictability.

  18. Filtration of human EEG recordings from physiological artifacts with empirical mode method

    Science.gov (United States)

    Grubov, Vadim V.; Runnova, Anastasiya E.; Khramova, Marina V.

    2017-03-01

    In the paper we propose the new method for dealing with noise and physiological artifacts in experimental human EEG recordings. The method is based on analysis of EEG signals with empirical mode decomposition (Hilbert-Huang transform). We consider noises and physiological artifacts on EEG as specific oscillatory patterns that cause problems during EEG analysis and can be detected with additional signals recorded simultaneously with EEG (ECG, EMG, EOG, etc.) We introduce the algorithm of the method with following steps: empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing empirical modes with artifacts, reconstruction of the initial EEG signal. We test the method on filtration of experimental human EEG signals from eye-moving artifacts and show high efficiency of the method.

  19. PENGEMBANGAN ALAT BANTU PEMODELAN TERAPI LENGAN PASCA STROKE DENGAN MEMANFAATKAN SINYAL ELECTROENCEPHALOGRAPHY (EEG) MENGGUNAKAN EMOTIV

    OpenAIRE

    Fatmawati, Ester; Prawito, Prawito; Wijaya, Sastra Kusuma

    2016-01-01

    Design modeling has been done post-stroke therapy arm by utilizing command brain signals generated by Electroencephalography (EEG). EEG signals provides a lot of information, one of which is motor information. Every body moving describe the unique form of brain signals. In conditions paralysis, motor information on the EEG signals will still be found when someone tries to move his limbs. The basic concepts of this study are the EEG signal acquisition using the Emotiv EPOC +, controling signal...

  20. Brain perfusion SPECT and EEG findings in Rett syndrome

    International Nuclear Information System (INIS)

    Lappalainen, R.; Liewendahl, K.; Nikkinen, P.; Sainio, K.; Riikonen, R.S.

    1997-01-01

    Thirteen patients (mean age 8.4 + 5.3 years) with Rett syndrome (RS) were studied with EEG and 99m Tc-HMPAO SPECT. Eleven patients had background abnormalities and 10 patients paroxysmal activity in EEG. Hypoperfusion of varying severity was detected in 11 patients, 7 patients having multiple lesions. Bifrontal hypoperfusion, observed in 6 patients, was the most distinctive finding. Hypoperfusion was observed also in other cortical regions, except for the occipital lobes. There was no correlation between severity of the background abnormality or presence of paroxysmal activity in EEG and grade of hypoperfusion. There was, however, an association between the severity of hypoperfusion and early manifestation of symptoms in patients with RS. Whether this early-onset group of patients represents a different disease entity or only reflects disease variability the basic pathology being the same, is a possibility that deserves further clarification. (au) 37 refs

  1. Brain-computer interfaces for EEG neurofeedback: peculiarities and solutions.

    Science.gov (United States)

    Huster, René J; Mokom, Zacharais N; Enriquez-Geppert, Stefanie; Herrmann, Christoph S

    2014-01-01

    Neurofeedback training procedures designed to alter a person's brain activity have been in use for nearly four decades now and represent one of the earliest applications of brain-computer interfaces (BCI). The majority of studies using neurofeedback technology relies on recordings of the electroencephalogram (EEG) and applies neurofeedback in clinical contexts, exploring its potential as treatment for psychopathological syndromes. This clinical focus significantly affects the technology behind neurofeedback BCIs. For example, in contrast to other BCI applications, neurofeedback BCIs usually rely on EEG-derived features with only a minimum of additional processing steps being employed. Here, we highlight the peculiarities of EEG-based neurofeedback BCIs and consider their relevance for software implementations. Having reviewed already existing packages for the implementation of BCIs, we introduce our own solution which specifically considers the relevance of multi-subject handling for experimental and clinical trials, for example by implementing ready-to-use solutions for pseudo-/sham-neurofeedback. © 2013.

  2. HZI systems for EEG parametrization and classification of psychotropic drugs.

    Science.gov (United States)

    Itil, T M; Shapiro, D M; Herrmann, W M; Schulz, W; Morgan, V

    1979-01-01

    The EEG effects of twenty, clinically most frequently used psychotropic drugs and five placebos were studied in 75 male volunteers in five simultaneously designed basic studies. In each of the five studies single oral dosages of five drugs (well known representatives of neuroleptics, antidepressants, anxiolytics and psychostimulants, as well as placebos) were investigated in 15 subjects in a double-blind latin-square research design using the methods of the Quantitative Pharmaco-EEG. The results demonstrated that the therapeutically equivalent effective compounds also have similar effects on human EEG. With a classification rule, based on discriminant function 20, and with a classification rule, based on correlation statistics 19 of 25 compounds could be reclassified into correct clinical-therapeutic psychotropic drug groups. It is suggested that CEEG is an important tool in predicting and describing psychotropic properties of compounds, and should routinely be used in psychotropic drug development.

  3. Brain perfusion SPECT and EEG findings in Rett syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lappalainen, R. [Children`s Castle Hospital, Dept. of Child Neurology, Helsinki (Finland); Liewendahl, K.; Nikkinen, P. [Univ. Central Hospital, Division of Nuclear Medicine, Laboratory Dept., Helsinki (Finland); Sainio, K.; Riikonen, R.S. [Univ. Central Hospital, Child Neurology, Helsinki (Finland)

    1997-01-01

    Thirteen patients (mean age 8.4 + 5.3 years) with Rett syndrome (RS) were studied with EEG and {sup 99m}Tc-HMPAO SPECT. Eleven patients had background abnormalities and 10 patients paroxysmal activity in EEG. Hypoperfusion of varying severity was detected in 11 patients, 7 patients having multiple lesions. Bifrontal hypoperfusion, observed in 6 patients, was the most distinctive finding. Hypoperfusion was observed also in other cortical regions, except for the occipital lobes. There was no correlation between severity of the background abnormality or presence of paroxysmal activity in EEG and grade of hypoperfusion. There was, however, an association between the severity of hypoperfusion and early manifestation of symptoms in patients with RS. Whether this early-onset group of patients represents a different disease entity or only reflects disease variability the basic pathology being the same, is a possibility that deserves further clarification. (au) 37 refs.

  4. Ictal headache and visual sensitivity

    NARCIS (Netherlands)

    Piccioli, M.; Parisi, P.; Tisei, P.; Villa, M. P.; Buttinelli, C.; Kasteleijn-Nolst Trenite, D. G. A.

    Migrainous headache is reported by patients with photosensitive epilepsy, whereas their relatives complain more often about headache than the relatives of patients with other types of epilepsy. We therefore investigated whether headache itself could be an epileptic symptom related to

  5. Psychogenic non-epileptic seizures: our video-EEG experience.

    Science.gov (United States)

    Nežádal, Tomáš; Hovorka, Jiří; Herman, Erik; Němcová, Iveta; Bajaček, Michal; Stichová, Eva

    2011-09-01

    The aim of our study was to assess the number of psychogenic non-epileptic seizures (PNES) in our patients with a refractory seizure disorder, to determine the 'typical' PNES semiology using video-EEG monitoring and describe other PNES parameters. We evaluated prospectively 596 patients with pharmacoresistant seizures. All these patients underwent continuous video-EEG monitoring. In consenting patients, we used suggestive seizure provocation. We assessed seizure semiology, interictal EEG, brain MRI, psychiatric co-morbidities, personality profiles, and seizure outcome. In the sample of 596 monitored patients, we detected 111 (19.3%) patients with PNES. Of the 111 patients with PNES, 86.5% had spontaneous and 76.5% had provoked seizures. The five most typical symptoms were: initially closed eyelids (67.6%), rapid tremor (47.7%), asynchronous limb movement (37.8%), preictal pseudosleep (33.3%), and side-to-side head movement (32.4%). Interictal EEG was rated as abnormal in 46.2% and with epileptiform abnormality in 9%. Brain MRI was abnormal in 32 (28.8%) patients. Personality disorders (46.8%), anxiety (39.6%), and depression (12.6%) were the most frequent additional psychiatric co-morbidities. PNES outcome after at least 2 years is reported; 22.5% patients was seizure-free; one-third had markedly reduced seizure frequency. We have not seen any negative impact of the provocative testing on the seizure outcome. Video-EEG monitoring with suggestive seizure provocation supported by clinical psychiatric and psychological evaluation significantly contributes to the correct PNES diagnosis, while interictal EEG and brain MRI are frequently abnormal. Symptoms typical for PNES, as opposed to epileptic seizures, could be distinguished.

  6. Neural decoding of expressive human movement from scalp electroencephalography (EEG

    Directory of Open Access Journals (Sweden)

    Zachery Ryan Hernandez

    2014-04-01

    Full Text Available Although efforts to characterize human movement through EEG have revealed neural activities unique to limb control that can be used to infer movement kinematics, it is still unknown the extent to which EEG can be used to discern the expressive qualities that influence such movements. In this study we used EEG and inertial sensors to record brain activity and movement of five skilled and certified Laban Movement Analysis (LMA dancers. Each dancer performed whole body functional movements of three Action types: movements devoid of expressive qualities ('Neutral', non-expressive movements while thinking about specific expressive qualities ('Think’, and enacted expressive movements ('Do'. The expressive movement qualities that were used in the 'Think' and 'Do' actions consisted of a sequence of eight Laban Efforts as defined by LMA - a notation system and language for describing, visualizing, interpreting and documenting all varieties of human movement. We used delta band (0.2 – 4 Hz EEG as input to a machine learning algorithm that computed locality-preserving Fisher’s discriminant analysis (LFDA for dimensionality reduction followed by Gaussian mixture models (GMMs to decode the type of Action. We also trained our LFDA-GMM models to classify all the possible combinations of Action Type and Laban Effort (giving a total of 17 classes. Classification accuracy rates were 59.4 ± 0.6% for Action Type and 88.2 ± 0.7% for Laban Effort Type. Ancillary analyses of the potential relations between the EEG and movement kinematics of the dancer's body, indicated that motion-related artifacts did not significantly influence our classification results. In summary, this research demonstrates that EEG has valuable information about the expressive qualities of movement. These results may have applications for advancing the understanding of the neural basis of expressive movements and for the development of neuroprosthetics to restore movements.

  7. Classification of EEG Signals Based on Pattern Recognition Approach.

    Science.gov (United States)

    Amin, Hafeez Ullah; Mumtaz, Wajid; Subhani, Ahmad Rauf; Saad, Mohamad Naufal Mohamad; Malik, Aamir Saeed

    2017-01-01

    Feature extraction is an important step in the process of electroencephalogram (EEG) signal classification. The authors propose a "pattern recognition" approach that discriminates EEG signals recorded during different cognitive conditions. Wavelet based feature extraction such as, multi-resolution decompositions into detailed and approximate coefficients as well as relative wavelet energy were computed. Extracted relative wavelet energy features were normalized to zero mean and unit variance and then optimized using Fisher's discriminant ratio (FDR) and principal component analysis (PCA). A high density EEG dataset validated the proposed method (128-channels) by identifying two classifications: (1) EEG signals recorded during complex cognitive tasks using Raven's Advance Progressive Metric (RAPM) test; (2) EEG signals recorded during a baseline task (eyes open). Classifiers such as, K-nearest neighbors (KNN), Support Vector Machine (SVM), Multi-layer Perceptron (MLP), and Naïve Bayes (NB) were then employed. Outcomes yielded 99.11% accuracy via SVM classifier for coefficient approximations (A5) of low frequencies ranging from 0 to 3.90 Hz. Accuracy rates for detailed coefficients were 98.57 and 98.39% for SVM and KNN, respectively; and for detailed coefficients (D5) deriving from the sub-band range (3.90-7.81 Hz). Accuracy rates for MLP and NB classifiers were comparable at 97.11-89.63% and 91.60-81.07% for A5 and D5 coefficients, respectively. In addition, the proposed approach was also applied on public dataset for classification of two cognitive tasks and achieved comparable classification results, i.e., 93.33% accuracy with KNN. The proposed scheme yielded significantly higher classification performances using machine learning classifiers compared to extant quantitative feature extraction. These results suggest the proposed feature extraction method reliably classifies EEG signals recorded during cognitive tasks with a higher degree of accuracy.

  8. Data mining EEG signals in depression for their diagnostic value.

    Science.gov (United States)

    Mohammadi, Mahdi; Al-Azab, Fadwa; Raahemi, Bijan; Richards, Gregory; Jaworska, Natalia; Smith, Dylan; de la Salle, Sara; Blier, Pierre; Knott, Verner

    2015-12-23

    Quantitative electroencephalogram (EEG) is one neuroimaging technique that has been shown to differentiate patients with major depressive disorder (MDD) and non-depressed healthy volunteers (HV) at the group-level, but its diagnostic potential for detecting differences at the individual level has yet to be realized. Quantitative EEGs produce complex data sets derived from digitally analyzed electrical activity at different frequency bands, at multiple electrode locations, and under different vigilance (eyes open vs. closed) states, resulting in potential feature patterns which may be diagnostically useful, but detectable only with advanced mathematical models. This paper uses a data mining methodology for classifying EEGs of 53 MDD patients and 43 HVs. This included: (a) pre-processing the data, including cleaning and normalization, applying Linear Discriminant Analysis (LDA) to map the features into a new feature space; and applying Genetic Algorithm (GA) to identify the most significant features; (b) building predictive models using the Decision Tree (DT) algorithm to discover rules and hidden patterns based on the reduced and mapped features; and (c) evaluating the models based on the accuracy and false positive values on the EEG data of MDD and HV participants. Two categories of experiments were performed. The first experiment analyzed each frequency band individually, while the second experiment analyzed the bands together. Application of LDA and GA markedly reduced the total number of utilized features by ≥ 50 % and, with all frequency bands analyzed together, the model showed average classification accuracy (MDD vs. HV) of 80 %. The best results from model testing with additional test EEG recordings from 9 MDD patients and 35 HV individuals demonstrated an accuracy of 80 % and showed an average sensitivity of 70 %, a specificity of 76 %, and a positive (PPV) and negative predictive value (NPV) of 74 and 75 %, respectively. These initial findings

  9. The effect of hypobaric hypoxia on multichannel EEG signal complexity.

    Science.gov (United States)

    Papadelis, Christos; Kourtidou-Papadeli, Chrysoula; Bamidis, Panagiotis D; Maglaveras, Nikos; Pappas, Konstantinos

    2007-01-01

    The objective of this study was the development and evaluation of nonlinear electroencephalography parameters which assess hypoxia-induced EEG alterations, and describe the temporal characteristics of different hypoxic levels' residual effect upon the brain electrical activity. Multichannel EEG, pO2, pCO2, ECG, and respiration measurements were recorded from 10 subjects exposed to three experimental conditions (100% oxygen, hypoxia, recovery) at three-levels of reduced barometric pressure. The mean spectral power of EEG under each session and altitude were estimated for the standard bands. Approximate Entropy (ApEn) of EEG segments was calculated, and the ApEn's time-courses were smoothed by a moving average filter. On the smoothed diagrams, parameters were defined. A significant increase in total power and power of theta and alpha bands was observed during hypoxia. Visual interpretation of ApEn time-courses revealed a characteristic pattern (decreasing during hypoxia and recovering after oxygen re-administration). The introduced qEEG parameters S1 and K1 distinguished successfully the three hypoxic conditions. The introduced parameters based on ApEn time-courses are assessing reliably and effectively the different hypoxic levels. ApEn decrease may be explained by neurons' functional isolation due to hypoxia since decreased complexity corresponds to greater autonomy of components, although this interpretation should be further supported by electrocorticographic animal studies. The introduced qEEG parameters seem to be appropriate for assessing the hypoxia-related neurophysiological state of patients in the hyperbaric chambers in the treatment of decompression sickness, carbon dioxide poisoning, and mountaineering.

  10. Signal distortion from microelectrodes in clinical EEG acquisition systems

    Science.gov (United States)

    Stacey, William C.; Kellis, Spencer; Patel, Paras R.; Greger, Bradley; Butson, Christopher R.

    2012-10-01

    Many centers are now using high-density microelectrodes during traditional intracranial electroencephalography (iEEG) both for research and clinical purposes. These microelectrodes are FDA-approved and integrate into clinical EEG acquisition systems. However, the electrical characteristics of these electrodes are poorly described and clinical systems were not designed to use them; thus, it is possible that this shift into clinical practice could have unintended consequences. In this study, we characterized the impedance of over 100 commercial macro- and microelectrodes using electrochemical impedance spectroscopy (EIS) to determine how electrode properties could affect signal acquisition and interpretation. The EIS data were combined with the published specifications of several commercial EEG systems to design digital filters that mimic the behavior of the electrodes and amplifiers. These filters were used to analyze simulated brain signals that contain a mixture of characteristic features commonly observed in iEEG. Each output was then processed with several common quantitative EEG measurements. Our results show that traditional macroelectrodes had low impedances and produced negligible distortion of the original signal. Brain tissue and electrical wiring also had negligible filtering effects. However, microelectrode impedances were much higher and more variable than the macroelectrodes. When connected to clinical amplifiers, higher impedance electrodes produced considerable distortion of the signal at low frequencies (impedance of at least 1 GΩ, which is much higher than most clinical systems. These results show that it is critical to account for variations in impedance when analyzing EEG from different-sized electrodes. Data from microelectrodes may yield misleading results unless recorded with high-impedance amplifiers.

  11. Simultaneous head tissue conductivity and EEG source location estimation.

    Science.gov (United States)

    Akalin Acar, Zeynep; Acar, Can E; Makeig, Scott

    2016-01-01

    Accurate electroencephalographic (EEG) source localization requires an electrical head model incorporating accurate geometries and conductivity values for the major head tissues. While consistent conductivity values have been reported for scalp, brain, and cerebrospinal fluid, measured brain-to-skull conductivity ratio (BSCR) estimates have varied between 8 and 80, likely reflecting both inter-subject and measurement method differences. In simulations, mis-estimation of skull conductivity can produce source localization errors as large as 3cm. Here, we describe an iterative gradient-based approach to Simultaneous tissue Conductivity And source Location Estimation (SCALE). The scalp projection maps used by SCALE are obtained from near-dipolar effective EEG sources found by adequate independent component analysis (ICA) decomposition of sufficient high-density EEG data. We applied SCALE to simulated scalp projections of 15cm(2)-scale cortical patch sources in an MR image-based electrical head model with simulated BSCR of 30. Initialized either with a BSCR of 80 or 20, SCALE estimated BSCR as 32.6. In Adaptive Mixture ICA (AMICA) decompositions of (45-min, 128-channel) EEG data from two young adults we identified sets of 13 independent components having near-dipolar scalp maps compatible with a single cortical source patch. Again initialized with either BSCR 80 or 25, SCALE gave BSCR estimates of 34 and 54 for the two subjects respectively. The ability to accurately estimate skull conductivity non-invasively from any well-recorded EEG data in combination with a stable and non-invasively acquired MR imaging-derived electrical head model could remove a critical barrier to using EEG as a sub-cm(2)-scale accurate 3-D functional cortical imaging modality. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Can EEG Differentiate Among Syndromes in Genetic Generalized Epilepsy?

    Science.gov (United States)

    Seneviratne, Udaya; Hepworth, Graham; Cook, Mark; DʼSouza, Wendyl

    2017-05-01

    To evaluate EEG differences among syndromes in genetic generalized epilepsy based on quantified data. Twenty-four-hour ambulatory EEGs were recorded in consecutive patients diagnosed with genetic generalized epilepsy. All epileptiform EEG abnormalities were quantified into density scores (total duration of epileptiform discharges per hour). One-way analysis of variance was conducted to find out differences in EEG density scores among the syndromes. Generalized linear mixed models were also fitted to explore the association between the proportion of "pure" generalized spike-wave paroxysms and fragments (without intervening polyspikes/polyspike-waves) and the syndromes. In total, 6,923 epileptiform discharges were analyzed from 105 abnormal EEGs. In the analysis of variance, six EEG variables were significantly different among syndromes: total spike density (P = 0.001), total polyspike and polyspike-wave density (P = 0.049), generalized spike-wave-only density (P paroxysm density (P paroxysm duration mean (P = 0.018), and generalized paroxysm duration maximum (P = 0.009). The density of epileptiform discharges and the paroxysm durations were the highest in juvenile absence epilepsy followed by juvenile myoclonic epilepsy, childhood absence epilepsy, and generalized epilepsy with tonic-clonic seizures only. Generalized linear mixed models revealed that "pure" generalized spike-wave discharges (without intervening polyspikes/polyspike waves) tended to be more frequent in absence epilepsies, although the difference was not statistically significant (P = 0.21). The findings of this study suggest that the density and duration of epileptiform discharges can help differentiate among genetic generalized epilepsy syndromes.

  13. Classification of EEG Signals Based on Pattern Recognition Approach

    Directory of Open Access Journals (Sweden)

    Hafeez Ullah Amin

    2017-11-01

    Full Text Available Feature extraction is an important step in the process of electroencephalogram (EEG signal classification. The authors propose a “pattern recognition” approach that discriminates EEG signals recorded during different cognitive conditions. Wavelet based feature extraction such as, multi-resolution decompositions into detailed and approximate coefficients as well as relative wavelet energy were computed. Extracted relative wavelet energy features were normalized to zero mean and unit variance and then optimized using Fisher's discriminant ratio (FDR and principal component analysis (PCA. A high density EEG dataset validated the proposed method (128-channels by identifying two classifications: (1 EEG signals recorded during complex cognitive tasks using Raven's Advance Progressive Metric (RAPM test; (2 EEG signals recorded during a baseline task (eyes open. Classifiers such as, K-nearest neighbors (KNN, Support Vector Machine (SVM, Multi-layer Perceptron (MLP, and Naïve Bayes (NB were then employed. Outcomes yielded 99.11% accuracy via SVM classifier for coefficient approximations (A5 of low frequencies ranging from 0 to 3.90 Hz. Accuracy rates for detailed coefficients were 98.57 and 98.39% for SVM and KNN, respectively; and for detailed coefficients (D5 deriving from the sub-band range (3.90–7.81 Hz. Accuracy rates for MLP and NB classifiers were comparable at 97.11–89.63% and 91.60–81.07% for A5 and D5 coefficients, respectively. In addition, the proposed approach was also applied on public dataset for classification of two cognitive tasks and achieved comparable classification results, i.e., 93.33% accuracy with KNN. The proposed scheme yielded significantly higher classification performances using machine learning classifiers compared to extant quantitative feature extraction. These results suggest the proposed feature extraction method reliably classifies EEG signals recorded during cognitive tasks with a higher degree of accuracy.

  14. Structured Sparsity Regularization Approach to the EEG Inverse Problem

    DEFF Research Database (Denmark)

    Montoya-Martinez, Jair; Artes-Rodriguez, Antonio; Hansen, Lars Kai

    2012-01-01

    Localization of brain activity involves solving the EEG inverse problem, which is an undetermined ill-posed problem. We propose a novel approach consisting in estimating, using structured sparsity regularization techniques, the Brain Electrical Sources (BES) matrix directly in the spatio......-temporal source space. We use proximal splitting optimization methods, which are efficient optimization techniques, with good convergence rates and with the ability to handle large nonsmooth convex problems, which is the typical scenario in the EEG inverse problem. We have evaluated our approach under a simulated...

  15. The EEG response to the repromulgated standard and compliance process

    International Nuclear Information System (INIS)

    Neill, R.H.; Chaturvedi, L.; Lee, W.W.L.

    1993-01-01

    Since 1978, the New Mexico Environmental Evaluation Group (EEG) has provided an independent technical evaluation of the Waste Isolation Pilot Plant (WIPP) to ensure protection of the public health and safety of New Mexicans and protection of the environment in New Mexico. Through its technical competence and continuity, the EEG has had a major influence on the course of the WIPP. This paper summarizes our views on the 1993 repromulgation of the general environmental standards for high-level and transuranic waste disposal and the certification for compliance with the standard

  16. Electroencephalography (EEG) Based Control in Assistive Mobile Robots: A Review

    International Nuclear Information System (INIS)

    Krishnan, N Murali; Mariappan, Muralindran; Muthukaruppan, Karthigayan; Hijazi, Mohd Hanafi Ahmad; Kitt, Wong Wei

    2016-01-01

    Recently, EEG based control in assistive robot usage has been gradually increasing in the area of biomedical field for giving quality and stress free life for disabled and elderly people. This study reviews the deployment of EGG based control in assistive robots, especially for those who in need and neurologically disabled. The main objective of this paper is to describe the methods used for (i) EEG data acquisition and signal preprocessing, (ii) feature extraction and (iii) signal classification methods. Besides that, this study presents the specific research challenges in the designing of these control systems and future research directions. (paper)

  17. Global Manufacturing Research: Experience Exchange Group (EEG) contributions

    DEFF Research Database (Denmark)

    Bruun, Peter

    1998-01-01

    The intention of this paper is to clarify if and how an ExperienceExchange Group (EEG) can be involved in a research process in the areaof industrial management. For exemplification of the topic an ongoingresearch in global manufacturing is referred to. In this research itwas after a series...... activities aredescribed and a tentative coupling to the phases in a research processis proposed. Following this is a discussion of methodological andquality requirements. It is considered how EEG activities couldpossible contribute to an industrial rooted research. The paper endsup looking at future research...

  18. Pharmaco-EEG Studies in Animals: A History-Based Introduction to Contemporary Translational Applications.

    Science.gov (United States)

    Drinkenburg, Wilhelmus H I M; Ahnaou, Abdallah; Ruigt, Gé S F

    2015-01-01

    Current research on the effects of pharmacological agents on human neurophysiology finds its roots in animal research, which is also reflected in contemporary animal pharmaco-electroencephalography (p-EEG) applications. The contributions, present value and translational appreciation of animal p-EEG-based applications are strongly interlinked with progress in recording and neuroscience analysis methodology. After the pioneering years in the late 19th and early 20th century, animal p-EEG research flourished in the pharmaceutical industry in the early 1980s. However, around the turn of the millennium the emergence of structurally and functionally revealing imaging techniques and the increasing application of molecular biology caused a temporary reduction in the use of EEG as a window into the brain for the prediction of drug efficacy. Today, animal p-EEG is applied again for its biomarker potential - extensive databases of p-EEG and polysomnography studies in rats and mice hold EEG signatures of a broad collection of psychoactive reference and test compounds. A multitude of functional EEG measures has been investigated, ranging from simple spectral power and sleep-wake parameters to advanced neuronal connectivity and plasticity parameters. Compared to clinical p-EEG studies, where the level of vigilance can be well controlled, changes in sleep-waking behaviour are generally a prominent confounding variable in animal p-EEG studies and need to be dealt with. Contributions of rodent pharmaco-sleep EEG research are outlined to illustrate the value and limitations of such preclinical p-EEG data for pharmacodynamic and chronopharmacological drug profiling. Contemporary applications of p-EEG and pharmaco-sleep EEG recordings in animals provide a common and relatively inexpensive window into the functional brain early in the preclinical and clinical development of psychoactive drugs in comparison to other brain imaging techniques. They provide information on the impact of

  19. Spontaneous brain activity and EEG microstates. A novel EEG/fMRI analysis approach to explore resting-state networks.

    Science.gov (United States)

    Musso, F; Brinkmeyer, J; Mobascher, A; Warbrick, T; Winterer, G

    2010-10-01

    The brain is active even in the absence of explicit input or output as demonstrated from electrophysiological as well as imaging studies. Using a combined approach we measured spontaneous fluctuations in the blood oxygen level dependent (BOLD) signal along with electroencephalography (EEG) in eleven healthy subjects during relaxed wakefulness (eyes closed). In contrast to other studies which used the EEG frequency information to guide the functional MRI (fMRI) analysis, we opted for transient EEG events, which identify and quantify brain electric microstates as time epochs with quasi-stable field topography. We then used this microstate information as regressors for the BOLD fluctuations. Single trial EEGs were segmented with a specific module of the LORETA (low resolution electromagnetic tomography) software package in which microstates are represented as normalized vectors constituted by scalp electric potentials, i.e., the related 3-dimensional distribution of cortical current density in the brain. Using the occurrence and the duration of each microstate, we modeled the hemodynamic response function (HRF) which revealed BOLD activation in all subjects. The BOLD activation patterns resembled well known resting-state networks (RSNs) such as the default mode network. Furthermore we "cross validated" the data performing a BOLD independent component analysis (ICA) and computing the correlation between each ICs and the EEG microstates across all subjects. This study shows for the first time that the information contained within EEG microstates on a millisecond timescale is able to elicit BOLD activation patterns consistent with well known RSNs, opening new avenues for multimodal imaging data processing. Copyright 2010. Published by Elsevier Inc.

  20. EEG Sequence Imaging: A Markov Prior for the Variational Garrote

    DEFF Research Database (Denmark)

    Hansen, Sofie Therese; Hansen, Lars Kai

    2013-01-01

    We propose the following generalization of the Variational Garrote for sequential EEG imaging: A Markov prior to promote sparse, but temporally smooth source dynamics. We derive a set of modied Variational Garrote updates and analyze the role of the prior's hyperparameters. An experimental...

  1. Low Cost Electrode Assembly for EEG Recordings in Mice

    Directory of Open Access Journals (Sweden)

    Emily C. Vogler

    2017-11-01

    Full Text Available Wireless electroencephalography (EEG of small animal subjects typically utilizes miniaturized EEG devices which require a robust recording and electrode assembly that remains in place while also being well-tolerated by the animal so as not to impair the ability of the animal to perform normal living activities or experimental tasks. We developed simple and fast electrode assembly and method of electrode implantation using electrode wires and wire-wrap technology that provides both higher survival and success rates in obtaining recordings from the electrodes than methods using screws as electrodes. The new wire method results in a 51% improvement in the number of electrodes that successfully record EEG signal. Also, the electrode assembly remains affixed and provides EEG signal for at least a month after implantation. Screws often serve as recording electrodes, which require either drilling holes into the skull to insert screws or affixing screws to the surface of the skull with adhesive. Drilling holes large enough to insert screws can be invasive and damaging to brain tissue, using adhesives may interfere with conductance and result in a poor signal, and soldering screws to wire leads results in fragile connections. The methods presented in this article provide a robust implant that is minimally invasive and has a significantly higher success rate of electrode implantation. In addition, the implant remains affixed and produces good recordings for over a month, while using economical, easily obtained materials and skills readily available in most animal research laboratories.

  2. A stochastic model for EEG microstate sequence analysis.

    Science.gov (United States)

    Gärtner, Matthias; Brodbeck, Verena; Laufs, Helmut; Schneider, Gaby

    2015-01-01

    The analysis of spontaneous resting state neuronal activity is assumed to give insight into the brain function. One noninvasive technique to study resting state activity is electroencephalography (EEG) with a subsequent microstate analysis. This technique reduces the recorded EEG signal to a sequence of prototypical topographical maps, which is hypothesized to capture important spatio-temporal properties of the signal. In a statistical EEG microstate analysis of healthy subjects in wakefulness and three stages of sleep, we observed a simple structure in the microstate transition matrix. It can be described with a first order Markov chain in which the transition probability from the current state (i.e., map) to a different map does not depend on the current map. The resulting transition matrix shows a high agreement with the observed transition matrix, requiring only about 2% of mass transport (1/2 L1-distance). In the second part, we introduce an extended framework in which the simple Markov chain is used to make inferences on a potential underlying time continuous process. This process cannot be directly observed and is therefore usually estimated from discrete sampling points of the EEG signal given by the local maxima of the global field power. Therefore, we propose a simple stochastic model called sampled marked intervals (SMI) model that relates the observed sequence of microstates to an assumed underlying process of background intervals and thus, complements approaches that focus on the analysis of observable microstate sequences. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Prospective motion correction for MRI using EEG-equipment

    DEFF Research Database (Denmark)

    Andersen, Mads; Madsen, Kristoffer Hougaard; Hanson, Lars G.

    2016-01-01

    A new prospective motion correction technique is presented that is based on signals from gradient switching, in an EEG-cap with interconnected electrodes the subject wears during scanning. The method has no line-of-sight limitations as optical methods, requires no interleaved navigator modules...

  4. Extended BSI for continuous EEG monitoring in carotid endarterectomy

    NARCIS (Netherlands)

    van Putten, Michel Johannes Antonius Maria

    2006-01-01

    Abstract Objective Carotid endarterectomy is a common procedure as a secondary prevention of stroke, and is often performed with selective shunting. Although various EEG parameters have been proposed to determine if the brain is at risk during carotid artery clamping, the common procedure is still

  5. Epilepsy and EEG abnormalities in children with autism

    Czech Academy of Sciences Publication Activity Database

    Blatný, Marek; Urbánek, Tomáš; Komárek, V.; Hrdlička, M.; Faladová, L.; Zumrová, A.; Neuschlová, L.; Kulísek, R.

    Supplement 8, č. 43 (2002), s. 176-177 ISSN 0013-9580. [European Congress on Epileptology /5./. 06.10.2002-10.10.2002, Madrid] Institutional research plan: CEZ:AV0Z7025918 Keywords : Epilepsy * EEG * autism Subject RIV: AN - Psychology

  6. A three domain covariance framework for EEG/MEG data

    NARCIS (Netherlands)

    Ros, B.P.; Bijma, F.; de Gunst, M.C.M.; de Munck, J.C.

    2015-01-01

    In this paper we introduce a covariance framework for the analysis of single subject EEG and MEG data that takes into account observed temporal stationarity on small time scales and trial-to-trial variations. We formulate a model for the covariance matrix, which is a Kronecker product of three

  7. EEG Phase Synchronization In Patients With Paranoid Schizophrenia

    Czech Academy of Sciences Publication Activity Database

    Bob, P.; Paluš, Milan; Šusta, M.; Glaslová, K.

    2008-01-01

    Roč. 447, č. 1 (2008), s. 73-77 ISSN 0304-3940 Grant - others:GA MŠk(CZ) 1M06039 Institutional research plan: CEZ:AV0Z10300504 Keywords : EEG * phase synchronization * coherence * schizophrenia * feature binding Subject RIV: FH - Neurology Impact factor: 2.200, year: 2008

  8. Acute toxicity and sleep-wake EEG analysis of Stachtarpheta ...

    African Journals Online (AJOL)

    The effect of systemic administration of TASC on sleep architecture in rats was also evaluated in Sprague-Dawley rats that were chronically implanted with electrodes for electroencephalogram (EEG) and electromyogram (EMG) recording. The acute toxicity test revealed no lethal effect with doses of SCCR (up to 2000 ...

  9. Review of sleep-EEG in preterm and term neonates.

    Science.gov (United States)

    Dereymaeker, Anneleen; Pillay, Kirubin; Vervisch, Jan; De Vos, Maarten; Van Huffel, Sabine; Jansen, Katrien; Naulaers, Gunnar

    2017-10-01

    Neonatal sleep is a crucial state that involves endogenous driven brain activity, important for neuronal survival and guidance of brain networks. Sequential EEG-sleep analysis in preterm infants provides insights into functional brain integrity and can document deviations of the biologically pre-programmed process of sleep ontogenesis during the neonatal period. Visual assessment of neonatal sleep-EEG, with integration of both cerebral and non-cerebral measures to better define neonatal state, is still considered the gold standard. Electrographic patterns evolve over time and are gradually time locked with behavioural characteristics which allow classification of quiet sleep and active sleep periods during the last 10weeks of gestation. Near term age, the neonate expresses a short ultradian sleep cycle, with two distinct active and quiet sleep, as well as brief periods of transitional or indeterminate sleep. Qualitative assessment of neonatal sleep is however challenged by biological and environmental variables that influence the expression of EEG-sleep patterns and sleep organization. Developing normative EEG-sleep data with the aid of automated analytic methods, can further improve our understanding of extra-uterine brain development and state organization under stressful or pathological conditions. Based on those developmental biomarkers of normal and abnormal brain function, research can be conducted to support and optimise sleep in the NICU, with the ultimate goal to improve therapeutic interventions and neurodevelopmental outcome. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Finding neural correlates of drift diffusion processes in EEG oscillations

    NARCIS (Netherlands)

    van Vugt, M. K.; Simen, P.; Cohen, J. D.; Carlson, L.; Hölscher, C.; Shipley, T.

    2011-01-01

    Recent studies have begun to elucidate the neural correlates of evidence accumulation in perceptual decision making. Few of them have used a combined modeling-electrophysiological approach to studying evidence accumulation. We introduce a novel multivariate approach to EEG analysis with which we can

  11. Expression of behaviour and psychoactive drugs in the rat EEG

    NARCIS (Netherlands)

    Lier, Hester van

    2004-01-01

    Brain activity and behaviour are related to each other. Psychoactive drugs can influence both brain activity and behaviour. In order to be able to understand the interplay between brain activity as measured by the electroencephalogram (EEG), behaviour, and psychoactive drugs, it is not sufficient to

  12. EEG changes and neuroimaging abnormalities in relevance to ...

    African Journals Online (AJOL)

    Background: Autism is currently viewed as a genetically determined neurodevelopmental disorder although its defi nite underlying etiology remains to be established. Aim of the Study: Our purpose was to assess autism related morphological neuroimaging changes of the brain and EEG abnormalities in correlation to the ...

  13. Predictive value of EEG in neonates with periventricular leukomalacia.

    NARCIS (Netherlands)

    Vermeulen, R.; Sie, L.T.L.; Jonkman, E.J.; Strijers, R.L.; Lafeber, H.N.; Uitdehaag, B.M.J.; Knaap, M.S. van der

    2003-01-01

    The aim of this study was to evaluate whether EEG (i.e. positive Rolandic sharp waves) can be used to predict neurodevelopment in newborn infants with periventricular leukomalacia and compare the predictive value with that of MRI. A sequential cohort of neonates (n=45; 33 males, 12 females; mean

  14. Feasibility of Seizure Prediction from intracranial EEG Recordings

    DEFF Research Database (Denmark)

    Henriksen, Jonas; Kjær, Troels; Thomsen, Carsten E.

    2009-01-01

    Purpose: The current project evaluated the feasibility of providing an algorithm that could warn a patient of a forthcoming seizure based on iEEG recordings. Method: The mean phase coherence (MPC) feature (Mormann F et al. Phys Nonlinear Phenom 2000;3-4:358-369.) was implemented and tested in a r...

  15. Covariation of spectral and nonlinear EEG measures with alpha biofeedback.

    NARCIS (Netherlands)

    Fell, J.; Elfadil, H.; Klaver, P.; Roschke, J.; Elger, C.E.; Fernandez, G.S.E.

    2002-01-01

    This study investigated how different spectral and nonlinear EEG measures covaried with alpha power during auditory alpha biofeedback training, performed by 13 healthy subjects. We found a significant positive correlation of alpha power with the largest Lyapunov-exponent, pointing to an increased

  16. Expression of behaviour and psychoactive Drugs in the Rat EEG

    NARCIS (Netherlands)

    Lier, H. van

    2004-01-01

    Brain activity and behaviour are related to each other. Psychoactive drugs can influence both brain activity and behaviour. In order to be able to understand the interplay between brain activity as measured by the electroencephalogram (EEG), behaviour, and psychoactive drugs, it is not sufficient to

  17. [Wavelet entropy analysis of spontaneous EEG signals in Alzheimer's disease].

    Science.gov (United States)

    Zhang, Meiyun; Zhang, Benshu; Chen, Ying

    2014-08-01

    Wavelet entropy is a quantitative index to describe the complexity of signals. Continuous wavelet transform method was employed to analyze the spontaneous electroencephalogram (EEG) signals of mild, moderate and severe Alzheimer's disease (AD) patients and normal elderly control people in this study. Wavelet power spectrums of EEG signals were calculated based on wavelet coefficients. Wavelet entropies of mild, moderate and severe AD patients were compared with those of normal controls. The correlation analysis between wavelet entropy and MMSE score was carried out. There existed significant difference on wavelet entropy among mild, moderate, severe AD patients and normal controls (Pwavelet entropy for mild, moderate, severe AD patients was significantly lower than that for normal controls, which was related to the narrow distribution of their wavelet power spectrums. The statistical difference was significant (Pwavelet entropy of EEG and the MMSE score were significantly correlated (r= 0. 601-0. 799, PWavelet entropy is a quantitative indicator describing the complexity of EEG signals. Wavelet entropy is likely to be an electrophysiological index for AD diagnosis and severity assessment.

  18. Effect of negative and positive emotions on EEG spectral asymmetry.

    Science.gov (United States)

    Orgo, L; Bachmann, M; Lass, J; Hinrikus, H

    2015-08-01

    The aim of the study was to evaluate the applicability of electroencephalogram (EEG) spectral asymmetry index (SASI) for discrimination of the effect of negative and positive emotions on human brain bioelectrical activity. SASI has been previously proposed as a method to detect depression based on the balance of EEG theta and beta frequency band powers. Emotions were evoked on 22 healthy subjects using emotional pictures portraying humans from International Affective Picture System (IAPS) and late response to stimuli was examined (1700-2200 ms). Electroencephalogram (EEG) was recorded in 30 channels divided into 10 brain regions: left frontal, right frontal, left temporal, right temporal, frontal, frontocentral, central, centroparietal, parietal and occipital. Negative stimuli, compared to neutral stimuli, significantly increased SASI in frontocentral, central, centroparietal, parietal and occipital areas. Positive stimuli, compared to neutral stimuli, significantly decreased SASI in left temporal, centroparietal, parietal and occipital areas. The results indicate that SASI provides a good discrimination between the effects of negative, neutral and positive emotions on human EEG.

  19. Multi-scale symbolic transfer entropy analysis of EEG

    Science.gov (United States)

    Yao, Wenpo; Wang, Jun

    2017-10-01

    From both global and local perspectives, we symbolize two kinds of EEG and analyze their dynamic and asymmetrical information using multi-scale transfer entropy. Multi-scale process with scale factor from 1 to 199 and step size of 2 is applied to EEG of healthy people and epileptic patients, and then the permutation with embedding dimension of 3 and global approach are used to symbolize the sequences. The forward and reverse symbol sequences are taken as the inputs of transfer entropy. Scale factor intervals of permutation and global way are (37, 57) and (65, 85) where the two kinds of EEG have satisfied entropy distinctions. When scale factor is 67, transfer entropy of the healthy and epileptic subjects of permutation, 0.1137 and 0.1028, have biggest difference. And the corresponding values of the global symbolization is 0.0641 and 0.0601 which lies in the scale factor of 165. Research results show that permutation which takes contribution of local information has better distinction and is more effectively applied to our multi-scale transfer entropy analysis of EEG.

  20. Real-time mental arithmetic task recognition from EEG signals.

    Science.gov (United States)

    Wang, Qiang; Sourina, Olga

    2013-03-01

    Electroencephalography (EEG)-based monitoring the state of the user's brain functioning and giving her/him the visual/audio/tactile feedback is called neurofeedback technique, and it could allow the user to train the corresponding brain functions. It could provide an alternative way of treatment for some psychological disorders such as attention deficit hyperactivity disorder (ADHD), where concentration function deficit exists, autism spectrum disorder (ASD), or dyscalculia where the difficulty in learning and comprehending the arithmetic exists. In this paper, a novel method for multifractal analysis of EEG signals named generalized Higuchi fractal dimension spectrum (GHFDS) was proposed and applied in mental arithmetic task recognition from EEG signals. Other features such as power spectrum density (PSD), autoregressive model (AR), and statistical features were analyzed as well. The usage of the proposed fractal dimension spectrum of EEG signal in combination with other features improved the mental arithmetic task recognition accuracy in both multi-channel and one-channel subject-dependent algorithms up to 97.87% and 84.15% correspondingly. Based on the channel ranking, four channels were chosen which gave the accuracy up to 97.11%. Reliable real-time neurofeedback system could be implemented based on the algorithms proposed in this paper.

  1. [The influence of visual imagery experience on EEG spatial organization].

    Science.gov (United States)

    Sviderskaia, N E; Taratynova, G V; Kozhedub, R G

    2005-01-01

    The comparison of EEG spatial organization between groups of 23 students of graphic arts department ("professional" subjects) and 39 subjects of another specialization ("non-professional" subjects) was made in order to find EEG correlates of visual imagery experience. Changes in the spatial organization of biopotentials (spatial synchronization and spatial disorder, spectral power and coherence) were analyzed while subjects mentally composed visual images from two simple elements, right angle and oblique line. The total number of elements presented for the image composition increased with each subsequent task (in total, four tasks were presented) from the number adequate to simultaneous perception and conscious processing (less than 7 +/- 2) to a much higher number. Intergroup differences, especially, in the degree of the spatial disorder (non-linear processes), were most evident under conditions when the subjects operated with a greater number of elements (tasks 3 and 4). This parameter increased more rapidly in "professionals" than in "non-professionals". These changes were most pronounced in the right anterior cortex. In "non-professional" subjects, spatial synchronization (linear processes) increased in the right posterior area. In "professional" subjects, coherence and spectral power increased in a greater number of narrow EEG frequency subbands than in "non-professional" subjects. The findings suggest that the imagery performance in subjects with visual imagery experience involves complicated neurodynamic processes such as non-linear dynamics and numerous EEG spatial resonance systems.

  2. Drug taper during long-term video-EEG monitoring

    DEFF Research Database (Denmark)

    Guld, A. T.; Sabers, A.; Kjaer, T. W.

    2017-01-01

    Objectives: Anti-epileptic drugs (AED) are often tapered to reduce the time needed to record a sufficient number of seizure during long-term video-EEG monitoring (LTM). Fast AED reduction is considered less safe, but few studies have examined this. Our goal is to examine whether the rate of AED r...

  3. Sleep EEG spectral analysis in a diurnal rodent : Eutamias sibiricus

    NARCIS (Netherlands)

    DIJK, DJ; DAAN, S

    1989-01-01

    1. Sleep was studied in the diurnal rodent Eutamias sibiricus, chronically implanted with EEG and EMG electrodes. Analysis of the distribution of wakefulness, nonrapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep over the 24 h period (LD 12:12) showed that total sleep time was 27.5%

  4. Structural decomposition of EEG signatures of melodic processing

    NARCIS (Netherlands)

    Schaefer, R.S.; Desain, P.W.M.; Suppes, P.

    2009-01-01

    In the current study we investigate the EEG response to listening and imagining melodies and explore the possibility of decomposing this response according to musical features, such as rhythm and pitch patterns. A structural model was created based on musical aspects and multiple regression was used

  5. Fractal Dimension in Eeg Signals during Muscle Fatigue

    Science.gov (United States)

    Huang, Haibin; Yao, Bin; Yue, Guang; Brown, Robert; Jing, Liu

    2003-10-01

    Fractal dimension (FD) has been successfully used to characterize signals in the format of time series. In this study, we calculated FD of EEG signals recorded during human muscle fatigue as a measure of changes in the EEG signal complexity along fatigue. Subjects performed 200 intermittent handgrip contractions at 100contraction level. Each contraction lasted 2 s, followed by a 5-s rest. EEG data were recorded from the scalp along with handgrip force and muscle EMG signals. The FD computation was based on measurements of the length (Lk) of the signal at 6 different temporal resolutions (k = 1, 2, ¡­, 6). FD was determined from the relationship between Lk and k using the least square fit. The results showed that: (1) EEG fractal dimension associated with the motor performance was significantly higher than that during the rest period; (2) changes in the fractal dimension along the process of fatigue showed a significant correlation with the decline in force and EMG signals.

  6. Phase Synchronization in Human EEG During Audio-Visual Stimulation

    Czech Academy of Sciences Publication Activity Database

    Teplan, M.; Šušmáková, K.; Paluš, Milan; Vejmelka, Martin

    2009-01-01

    Roč. 28, - (2009), s. 80-84 ISSN 1536-8378 Grant - others:Bilateral project between Slovak AS and AS CR(CZ-SK) Modern methods for evaluation of electrophysiological signals Source of funding: V - iné verejné zdroje Keywords : synchronization * EEG * wavelet * audio- visual stimulation Subject RIV: FH - Neurology Impact factor: 0.729, year: 2009

  7. Effect of Low-Level Laser Stimulation on EEG

    Directory of Open Access Journals (Sweden)

    Jih-Huah Wu

    2012-01-01

    Full Text Available Conventional laser stimulation at the acupoint can induce significant brain activation, and the activation is theoretically conveyed by the sensory afferents. Whether the insensible low-level Laser stimulation outside the acupoint could also evoke electroencephalographic (EEG changes is not known. We designed a low-level laser array stimulator (6 pcs laser diode, wavelength 830 nm, output power 7 mW, and operation frequency 10 Hz to deliver insensible laser stimulations to the palm. EEG activities before, during, and after the laser stimulation were collected. The amplitude powers of each EEG frequency band were analyzed. We found that the low-level laser stimulation was able to increase the power of alpha rhythms and theta waves, mainly in the posterior head regions. These effects lasted at least 15 minutes after cessation of the laser stimulation. The amplitude power of beta activities in the anterior head regions decreased after laser stimulation. We thought these EEG changes comparable to those in meditation.

  8. Beamforming applied to surface EEG improves ripple visibility

    NARCIS (Netherlands)

    Mol, Arjen; van Klink, Nicole; Ferrier, Cyrille; Hillebrand, Arjan; Huiskamp, Geertjan; Zijlmans, Maeike

    2018-01-01

    Objective Surface EEG can show epileptiform ripples in people with focal epilepsy, but identification is impeded by the low signal-to-noise ratio of the electrode recordings. We used beamformer-based virtual electrodes to improve ripple identification. Methods We analyzed ten minutes of interictal

  9. Concordance of MRI and EEG Focal Slowing in Nonsyndromic Epilepsy

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2013-04-01

    Full Text Available Investigators at the Kangwon National University, Korea, and The Epilepsy Center, Lurie Children’s Hospital of Chicago, USA studied the correlation and significance of EEG focal slowing and focal MRI abnormalities in 253 children with nonsyndromic epilepsy.

  10. Preictal Dynamics of EEG Complexity in Intracranially Recorded Epileptic Seizure

    Czech Academy of Sciences Publication Activity Database

    Bob, P.; Roman, R.; Světlák, M.; Kukleta, M.; Chládek, Jan; Brázdil, M.

    2014-01-01

    Roč. 93, č. 23 (2014), el151:1-4 ISSN 0025-7974 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : EEG * epileptic Seizure Subject RIV: FS - Medical Facilities ; Equipment Impact factor: 5.723, year: 2014

  11. EEG activity in Carmelite nuns during a mystical experience.

    Science.gov (United States)

    Beauregard, Mario; Paquette, Vincent

    2008-10-17

    Mystical experiences relate to a fundamental dimension of human existence. These experiences, which are characterized by a sense of union with God, are commonly reported across all cultures. To date, no electroencephalography (EEG) study has been conducted to identify the neuroelectrical correlates of such experiences. The main objective of this study was to measure EEG spectral power and coherence in 14 Carmelite nuns during a mystical experience. EEG activity was recorded from 19 scalp locations during a resting state, a control condition and a mystical condition. In the mystical condition compared to control condition, electrode sites showed greater theta power at F3, C3, P3, Fz, Cz and Pz, and greater gamma1 power was detected at T4 and P4. Higher delta/beta ratio, theta/alpha ratio and theta/beta ratio were found for several electrode sites. In addition, FP1-C3 pair of electrodes displayed greater coherence for theta band while F4-P4, F4-T6, F8-T6 and C4-P4 pairs of electrodes showed greater coherence for alpha band. These results indicate that mystical experiences are mediated by marked changes in EEG power and coherence. These changes implicate several cortical areas of the brain in both hemispheres.

  12. The colorful brain: compact visualisation of routine EEG recordings

    NARCIS (Netherlands)

    van Putten, Michel Johannes Antonius Maria; Jarm, Tomaz; Kramar, Peter; Zupanic, Anze

    2007-01-01

    Clinical EEG recordings are typically evaluated by visual analysis of the various waveforms. Besides the long learning curve, it is rather subjective and prone to human error. To assist in the visual interpretation, various quantitative techniques have been proposed. Here, we describe a triplet of

  13. Continuous emotion detection using EEG signals and facial expressions

    NARCIS (Netherlands)

    Soleymani, Mohammad; Asghari-Esfeden, Sadjad; Pantic, Maja; Fu, Yun

    Emotions play an important role in how we select and consume multimedia. Recent advances on affect detection are focused on detecting emotions continuously. In this paper, for the first time, we continuously detect valence from electroencephalogram (EEG) signals and facial expressions in response to

  14. Fusion of Facial Expressions and EEG for Multimodal Emotion Recognition

    Directory of Open Access Journals (Sweden)

    Yongrui Huang

    2017-01-01

    Full Text Available This paper proposes two multimodal fusion methods between brain and peripheral signals for emotion recognition. The input signals are electroencephalogram and facial expression. The stimuli are based on a subset of movie clips that correspond to four specific areas of valance-arousal emotional space (happiness, neutral, sadness, and fear. For facial expression detection, four basic emotion states (happiness, neutral, sadness, and fear are detected by a neural network classifier. For EEG detection, four basic emotion states and three emotion intensity levels (strong, ordinary, and weak are detected by two support vector machines (SVM classifiers, respectively. Emotion recognition is based on two decision-level fusion methods of both EEG and facial expression detections by using a sum rule or a production rule. Twenty healthy subjects attended two experiments. The results show that the accuracies of two multimodal fusion detections are 81.25% and 82.75%, respectively, which are both higher than that of facial expression (74.38% or EEG detection (66.88%. The combination of facial expressions and EEG information for emotion recognition compensates for their defects as single information sources.

  15. Prompt recognition of brain states by their EEG signals

    DEFF Research Database (Denmark)

    Peters, B.O.; Pfurtscheller, G.; Flyvbjerg, H.

    1997-01-01

    Brain states corresponding to intention of movement of left and right index finger and right foot are classified by a ''committee'' of artificial neural networks processing individual channels of 56-electrode electroencephalograms (EEGs). Correct recognition is achieved in 83% of cases not previo...

  16. On the Keyhole Hypothesis: High Mutual Information between Ear and Scalp EEG

    Directory of Open Access Journals (Sweden)

    Kaare B. Mikkelsen

    2017-06-01

    Full Text Available We propose and test the keyhole hypothesis—that measurements from low dimensional EEG, such as ear-EEG reflect a broadly distributed set of neural processes. We formulate the keyhole hypothesis in information theoretical terms. The experimental investigation is based on legacy data consisting of 10 subjects exposed to a battery of stimuli, including alpha-attenuation, auditory onset, and mismatch-negativity responses and a new medium-long EEG experiment involving data acquisition during 13 h. Linear models were estimated to lower bound the scalp-to-ear capacity, i.e., predicting ear-EEG data from simultaneously recorded scalp EEG. A cross-validation procedure was employed to ensure unbiased estimates. We present several pieces of evidence in support of the keyhole hypothesis: There is a high mutual information between data acquired at scalp electrodes and through the ear-EEG “keyhole,” furthermore we show that the view—represented as a linear mapping—is stable across both time and mental states. Specifically, we find that ear-EEG data can be predicted reliably from scalp EEG. We also address the reverse view, and demonstrate that large portions of the scalp EEG can be predicted from ear-EEG, with the highest predictability achieved in the temporal regions and when using ear-EEG electrodes with a common reference electrode.

  17. Chebyshev and Modified Wavelet Algorithm Based Sleep Arousals Detection Using EEG Sensor Database

    Directory of Open Access Journals (Sweden)

    Mahalaxmi U. S. B. K.

    2017-04-01

    Full Text Available Electroencephalographic (EEG arousals are generally observed in EEG recordings as an awakening response of the human brain. Sleep apnea is a major sleep disorder. The patients, with Severe Sleep Apnea (SAS suffers from frequent interruptions in their sleep which brings about EEG arousals. In this paper, a new method for Segmentation and Filtering process of EEG sensor database signals for finding sleep arousals using Chebyshev and Modified Wavelet Algorithm is proposed. The Segmentation Algorithm appears as various features extracted from EEG Data’s and PSG Recordings. The Chebyshev Equiripple Filter is used in Filtering algorithm and then MSVM [M-Support Vector Machine] was utilized as Classification Tool. Algorithms are performed and different features are extracted and the ROC characteristics are performed. The extracted features are Delta, Gama, Beta, Alpha, Sigma of the EEG signal, EEG Signal Mean, EEG Signal Standard Deviation, EEG Signal Peak Signal to Noise Ratio [PSNR], and EEG Signal Normalization. MSVM tool showing EEG signals results.

  18. Alzheimer's disease: relationship between cognitive aspects and power and coherence EEG measures

    Directory of Open Access Journals (Sweden)

    Lineu C. Fonseca

    2011-12-01

    Full Text Available OBJECTIVE: To evaluate the relationship between specific cognitive aspects and quantitative EEG measures, in patients with mild or moderate Alzheimer's disease (AD. METHOD: Thirty-eight AD patients and 31 controls were assessed by CERAD neuropsychological battery (Consortium to Establish a Registry for AD and the electroencephalogram (EEG. The absolute power and coherences EEG measures were calculated at rest. The correlations between the cognitive variables and the EEG were evaluated. RESULTS: In the AD group there were significant correlations between different coherence EEG measures and Mini-Mental State Examination, verbal fluency, modified Boston naming, word list memory with repetition, word list recall and recognition, and constructional praxis (p<0.01. These correlations were all negative for the delta and theta bands and positive for alpha and beta. There were no correlations between cognitive aspects and absolute EEG power. CONCLUSION: The coherence EEG measures reflect different forms in the relationship between regions related to various cognitive dysfunctions.

  19. Emotion recognition from EEG using higher order crossings.

    Science.gov (United States)

    Petrantonakis, Panagiotis C; Hadjileontiadis, Leontios J

    2010-03-01

    Electroencephalogram (EEG)-based emotion recognition is a relatively new field in the affective computing area with challenging issues regarding the induction of the emotional states and the extraction of the features in order to achieve optimum classification performance. In this paper, a novel emotion evocation and EEG-based feature extraction technique is presented. In particular, the mirror neuron system concept was adapted to efficiently foster emotion induction by the process of imitation. In addition, higher order crossings (HOC) analysis was employed for the feature extraction scheme and a robust classification method, namely HOC-emotion classifier (HOC-EC), was implemented testing four different classifiers [quadratic discriminant analysis (QDA), k-nearest neighbor, Mahalanobis distance, and support vector machines (SVMs)], in order to accomplish efficient emotion recognition. Through a series of facial expression image projection, EEG data have been collected by 16 healthy subjects using only 3 EEG channels, namely Fp1, Fp2, and a bipolar channel of F3 and F4 positions according to 10-20 system. Two scenarios were examined using EEG data from a single-channel and from combined-channels, respectively. Compared with other feature extraction methods, HOC-EC appears to outperform them, achieving a 62.3% (using QDA) and 83.33% (using SVM) classification accuracy for the single-channel and combined-channel cases, respectively, differentiating among the six basic emotions, i.e., happiness, surprise, anger, fear, disgust, and sadness. As the emotion class-set reduces its dimension, the HOC-EC converges toward maximum classification rate (100% for five or less emotions), justifying the efficiency of the proposed approach. This could facilitate the integration of HOC-EC in human machine interfaces, such as pervasive healthcare systems, enhancing their affective character and providing information about the user's emotional status (e.g., identifying user's emotion

  20. Assessing quantitative EEG spectrograms to identify non-epileptic events.

    Science.gov (United States)

    Goenka, Ajay; Boro, Alexis; Yozawitz, Elissa

    2017-09-01

    To evaluate the sensitivity and specificity of quantitative EEG (QEEG) spectrograms in order to distinguish epileptic from non-epileptic events. Seventeen patients with paroxysmal non-epileptic events, captured during EEG monitoring, were retrospectively assessed using QEEG spectrograms. These patients were compared to a control group of 13 consecutive patients (ages 25-60 years) with epileptic seizures of similar semiology. Assessment of raw EEG was employed as the gold standard against which epileptic and non-epileptic events were validated. QEEG spectrograms, available using Persyst 12 EEG system integration software, were each assessed with respect to their usefulness to distinguish epileptic from non-epileptic seizures. The given spectrogram was interpreted as indicating a seizure if, at the time of the clinically identified event, it showed a visually significant change from baseline. Eighty-two clinically identified paroxysmal events were analysed (46 non-epileptic and 36 epileptic). The "seizure detector trend analysis" spectrogram correctly classified 33/46 (71%) non-epileptic events (no seizure indicated during a clinically identified event) vs. 29/36 (81%) epileptic seizures (seizure indicated during a clinically identified event) (p=0.013). Similarly, "rhythmicity spectrogram", FFT spectrogram, "asymmetry relative spectrogram", and integrated-amplitude EEG spectrogram detected 28/46 (61%), 30/46 (65%), 22/46 (48%) and 27/46 (59%) non-epileptic events vs. 27/36 (75%), 25/36 (69%), 25/36 (69%) and 27/36 (75%) epileptic events, respectively. High sensitivities and specificities for QEEG seizure detection analyses suggest that QEEG may have a role at the bedside to facilitate early differentiation between epileptic seizures and non-epileptic events in order to avoid unnecessary administration of antiepileptic drugs and possible iatrogenic consequences.

  1. Video ambulatory EEG: A good alternative to inpatient video telemetry?

    Science.gov (United States)

    Kandler, Rosalind; Ponnusamy, Athi; Wragg, Claire

    2017-04-01

    Video ambulatory EEG (V-AEEG) is a new technique which could add increased capacity for long term EEG monitoring to overstretched inpatient video telemetry (IPVT) services. We compare V-AEEG and IPVT for diagnostic efficacy, recording quality, patient acceptability and technologist time required. Forty-one V-AEEG and 64 IPVT adult patients were included. Patients were investigated to diagnose attacks or to obtain polysomnography (PSG) prior to multiple sleep latency test (MSLT). Number of attacks recorded, whether the diagnostic question was answered, quality of video and EEG recording and patients' preference for investigation at home or in hospital were noted. For V-AEEG patients, ease of procedure and extra technologist time required were recorded. Of patients investigated for diagnosis of attacks, 74% V-AEEG patients and 62% IPVT had typical attacks during the investigation. All PSGs were useful in interpreting the MSLTs. Diagnostic questions were answered by 73% V-AEEGs and 73% IPVTs. Quality of EEG and video recording was similar using V-AEEG and IPVT. Four patients had difficulty using V-AEEG equipment but diagnostic information was lost in only one. 5% of V-AEEG patients would have preferred hospital investigation but 45% of IPVT patients would have preferred home investigation. Extra technologist time for home visits (mean 2h) was required only for the first 7 patients. Video EEG recording quality and diagnostic efficacy from V-AEEG are similar to IPVT. V-AEEG is acceptable to most patients and does not require additional technical time. Hence, V-AEEG offers a convenient, economical alternative to IPVT. Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  2. Prediction of subjective ratings of emotional pictures by EEG features

    Science.gov (United States)

    McFarland, Dennis J.; Parvaz, Muhammad A.; Sarnacki, William A.; Goldstein, Rita Z.; Wolpaw, Jonathan R.

    2017-02-01

    Objective. Emotion dysregulation is an important aspect of many psychiatric disorders. Brain-computer interface (BCI) technology could be a powerful new approach to facilitating therapeutic self-regulation of emotions. One possible BCI method would be to provide stimulus-specific feedback based on subject-specific electroencephalographic (EEG) responses to emotion-eliciting stimuli. Approach. To assess the feasibility of this approach, we studied the relationships between emotional valence/arousal and three EEG features: amplitude of alpha activity over frontal cortex; amplitude of theta activity over frontal midline cortex; and the late positive potential over central and posterior mid-line areas. For each feature, we evaluated its ability to predict emotional valence/arousal on both an individual and a group basis. Twenty healthy participants (9 men, 11 women; ages 22-68) rated each of 192 pictures from the IAPS collection in terms of valence and arousal twice (96 pictures on each of 4 d over 2 weeks). EEG was collected simultaneously and used to develop models based on canonical correlation to predict subject-specific single-trial ratings. Separate models were evaluated for the three EEG features: frontal alpha activity; frontal midline theta; and the late positive potential. In each case, these features were used to simultaneously predict both the normed ratings and the subject-specific ratings. Main results. Models using each of the three EEG features with data from individual subjects were generally successful at predicting subjective ratings on training data, but generalization to test data was less successful. Sparse models performed better than models without regularization. Significance. The results suggest that the frontal midline theta is a better candidate than frontal alpha activity or the late positive potential for use in a BCI-based paradigm designed to modify emotional reactions.

  3. Increased theta band EEG power in sickle cell disease patients

    Directory of Open Access Journals (Sweden)

    Case M

    2017-12-01

    Full Text Available Michelle Case,1 Sina Shirinpour,1 Huishi Zhang,1 Yvonne H Datta,2 Stephen C Nelson,3 Karim T Sadak,4 Kalpna Gupta,2 Bin He1,5 1Department of Biomedical Engineering, 2Department of Medicine, University of Minnesota, 3Pediatric Hematology-Oncology, Children’s Hospitals and Clinics of Minnesota, 4Pediatric Hematology-Oncology, University of Minnesota Masonic Children’s Hospital, 5Institute for Engineering in Medicine, University of Minnesota, Minneapolis, MN, USA Objective: Pain is a major issue in the care of patients with sickle cell disease (SCD. The mechanisms behind pain and the best way to treat it are not well understood. We studied how electroencephalography (EEG is altered in SCD patients. Methods: We recruited 20 SCD patients and compared their resting state EEG to that of 14 healthy controls. EEG power was found across frequency bands using Welch’s method. Electrophysiological source imaging was assessed for each frequency band using the eLORETA algorithm. Results: SCD patients had increased theta power and decreased beta2 power compared to controls. Source localization revealed that areas of greater theta band activity were in areas related to pain processing. Imaging parameters were significantly correlated to emergency department visits, which indicate disease severity and chronic pain intensity. Conclusion: The present results support the pain mechanism referred to as thalamocortical dysrhythmia. This mechanism causes increased theta power in patients. Significance: Our findings show that EEG can be used to quantitatively evaluate differences between controls and SCD patients. Our results show the potential of EEG to differentiate between different levels of pain in an unbiased setting, where specific frequency bands could be used as biomarkers for chronic pain. Keywords: sickle cell disease, electroencephalography, chronic pain, electrophysiological source imaging, thalamocortical dysrhythmia

  4. Deep learning for EEG-Based preference classification

    Science.gov (United States)

    Teo, Jason; Hou, Chew Lin; Mountstephens, James

    2017-10-01

    Electroencephalogram (EEG)-based emotion classification is rapidly becoming one of the most intensely studied areas of brain-computer interfacing (BCI). The ability to passively identify yet accurately correlate brainwaves with our immediate emotions opens up truly meaningful and previously unattainable human-computer interactions such as in forensic neuroscience, rehabilitative medicine, affective entertainment and neuro-marketing. One particularly useful yet rarely explored areas of EEG-based emotion classification is preference recognition [1], which is simply the detection of like versus dislike. Within the limited investigations into preference classification, all reported studies were based on musically-induced stimuli except for a single study which used 2D images. The main objective of this study is to apply deep learning, which has been shown to produce state-of-the-art results in diverse hard problems such as in computer vision, natural language processing and audio recognition, to 3D object preference classification over a larger group of test subjects. A cohort of 16 users was shown 60 bracelet-like objects as rotating visual stimuli on a computer display while their preferences and EEGs were recorded. After training a variety of machine learning approaches which included deep neural networks, we then attempted to classify the users' preferences for the 3D visual stimuli based on their EEGs. Here, we show that that deep learning outperforms a variety of other machine learning classifiers for this EEG-based preference classification task particularly in a highly challenging dataset with large inter- and intra-subject variability.

  5. Correntropy measures to detect daytime sleepiness from EEG signals.

    Science.gov (United States)

    Melia, Umberto; Guaita, Marc; Vallverdú, Montserrat; Montserrat, Josep M; Vilaseca, Isabel; Salamero, Manel; Gaig, Carles; Caminal, Pere; Santamaria, Joan

    2014-10-01

    Excessive daytime sleepiness (EDS) is one of the main symptoms of several sleep related disorders and has a great impact on patients' lives. While many studies have been carried out in order to assess daytime sleepiness, automatic EDS detection still remains an open problem. In this work, a novel approach to this issue based on correntropy function analysis of EEG signals was proposed in order to detect patients suffering from EDS. Multichannel EEG signals were recorded during five Maintenance of Wakefulness Tests (MWT) and Multiple Sleep Latency Tests (MSLT) alternated throughout the day for patients suffering from sleep disordered breathing (SDB). A group of 20 patients with EDS was compared with a group of 20 patients without daytime sleepiness (WDS), by analyzing 60 s EEG windows in a waking state. Measures obtained from the cross-correntropy function (CCORR) and auto-correntropy function (ACORR) were calculated in the EEG frequency bands: δ, 0.1-4 Hz; θ, 4-8 Hz; α, 8-12 Hz; β, 12-30 Hz; total band TB, 0.1-45 Hz. These functions permitted the quantification of complex signal properties and the non-linear couplings between different areas of the scalp. Statistical differences between EDS and WDS groups were mainly found in the β band during MSLT events (p-value < 0.0001). The WDS group presented more complexity in the occipital zone than the EDS group, while a stronger nonlinear coupling between the occipital and frontal regions was detected in EDS patients than in the WDS group. At best, ACORR and CCORR measures yielded sensitivity and specificity above 80% and the area under ROC curve (AUC) was above 0.85 in classifying EDS and WDS patients. These performances represent an improvement with respect to classical EEG indices applied in the same database (sensitivity and specificity were never above 80% and AUC was under 0.75).

  6. Preoperational radiation surveillance of the WIPP project by EEG during 1992

    International Nuclear Information System (INIS)

    Kenney, J.W.

    1994-02-01

    The purpose of the EEG preoperational monitoring program is to document the existing concentrations of selected radionuclides in various environmental media collected from the vicinity of the WIPP site to provide a basis of comparison of any effects of future WT-PP operations. The basic methodology for conducting environmental surveillance both on-site and off-site was outlined by Spiegler (1984). This report represents a continuation of the EEG baseline data beginning in 1985, previously reported in EEG-43, EEG-47, EEG-49 and EEG-51. Such radionuclide baseline data are important in order to determine whether future WIPP operations with radioactive waste have affected concentrations of these radionuclides in the environment. EEG data are consistent with similar environmental measurements obtained by DOE beginning in 1985. Since late 1985, the EEG has collected or received as split samples 2 443 air filters with particulates, 202 water samples, 16 biota samples and 13 soil/sediment samples. A total of 5,946 specific radionuclide analyses have been performed on these samples. As reported previously by EEG (EEG-43, EEG-47, EEG-49 and EEG-51), observed concentrations of U-238 daughter radionuclides were not in equilibrium with the parent radionuclide in water samples. This observation is consistent with different radionuclide mobility in the environment. In a notice of proposed rule making for 40 CFR 141 (US EPA 1991), the Environmental Protection Agency (EPA) National Primary Drinking Water Regulations reflect this in the calculated activity-to-mass ratio of 1.3 pCi/μg of uranium using a geometric mean of the U-234:U-238 ratio in water supplies of 2.7. Ra-226 and Ra- 228 were reported in a number of water samples in concentrations similar to those previously published by EEG and DOE

  7. Hippocampal EEG and behaviour in dog. III. Hippocampal EEG correlates of stimulus-response tasks and of sexual behaviour

    NARCIS (Netherlands)

    Arnolds, D.E.A.T.; Lopes da Silva, F.H.; Aitink, J.W.; Kamp, A.

    A dog was trained to perform a spatial sound discrimination. The hippocampal EEG correlates and the movement correlates of correct trials were compared with those of incorrect trials and of ‘pressings in between’. Correct and wrong responses on a place learning task were compared both with

  8. The value of long term EEG monitoring in children: a comparison of ambulatory EEG and video telemetry.

    Science.gov (United States)

    Alix, James J P; Kandler, Rosalind H; Mordekar, Santosh R

    2014-09-01

    Outpatient ambulatory EEG may be followed by inpatient video telemetry EEG when investigating children for possible seizures and for classification of epilepsy. We investigated the value of ambulatory EEG and subsequent video telemetry recording in our centre. The departmental EEG database was interrogated retrospectively for children undergoing ambulatory recording followed by inpatient video telemetry within an 18-month period. 30 patients fitted these criteria, 21 females, 9 males, age range 3-16 years. The mean interval between studies was 9 months. For ambulatory recordings 93% of studies were undertaken to ascertain if behaviours were epileptic. 66% of ambulatory recordings studies captured an event of interest and 63% were able to answer the question asked of the test. In video telemetry recording 80% of studies were aimed at ascertaining if events were epileptic or not, 20% were undertaken for classification of seizure type. 70% of recordings captured an ictus and were considered helpful in addressing the clinical question. Pooled together 90% of patients had a paroxysmal event captured and the clinical question answered by the recording techniques. In patients for whom ambulatory recording failed to capture an attack or answer the clinical question, 70% went on to have a successful video telemetry recording. Both ambulatory EEG and inpatient video telemetry are effective tools for diagnosis of seizures. The majority of patients with failed ambulatory recordings go on to have successful video telemetry. Combining the two resources provides useful clinical information in nearly all instances. Copyright © 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  9. Effect of intermittent hypoxic training on hypoxia tolerance based on single-channel EEG.

    Science.gov (United States)

    Zhang, Tinglin; Wang, You; Li, Guang

    2016-03-23

    A single-channel algorithm was proposed in order to study effect of intermittent hypoxic training on hypoxia tolerance based on EEG pattern. EEG was decomposed by ensemble empirical mode decomposition into a finite number of intrinsic mode functions (IMFs) based on the intrinsic local characteristic time scale. Analytic amplitude, analytic frequency, and recurrence property quantified by recurrence quantification analysis were explored on IMFs, and the first two scales revealed difference between normal EEG and hypoxia EEG. Classification accuracy of hypoxia EEG and normal EEG could reach 67.8% before decline of neurobehavioral ability, which represented that hypoxia EEG pattern could be detected at an early stage. Classification accuracy of hypoxia EEG and normal EEG increased with time and deepened intensity of hypoxia was observed by regular shift of hypoxia EEG pattern with time in a three dimensional subspace. The reduced shift and classification accuracy after intermittent hypoxic training represented that hypoxia tolerance enhanced. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Safety and EEG data quality of concurrent high-density EEG and high-speed fMRI at 3 Tesla

    Science.gov (United States)

    Foged, Mette Thrane; Lindberg, Ulrich; Vakamudi, Kishore; Larsson, Henrik B. W.; Pinborg, Lars H.; Kjær, Troels W.; Fabricius, Martin; Svarer, Claus; Ozenne, Brice; Thomsen, Carsten; Beniczky, Sándor; Posse, Stefan

    2017-01-01

    Purpose Concurrent EEG and fMRI is increasingly used to characterize the spatial-temporal dynamics of brain activity. However, most studies to date have been limited to conventional echo-planar imaging (EPI). There is considerable interest in integrating recently developed high-speed fMRI methods with high-density EEG to increase temporal resolution and sensitivity for task-based and resting state fMRI, and for detecting interictal spikes in epilepsy. In the present study using concurrent high-density EEG and recently developed high-speed fMRI methods, we investigate safety of radiofrequency (RF) related heating, the effect of EEG on cortical signal-to-noise ratio (SNR) in fMRI, and assess EEG data quality. Materials and methods The study compared EPI, multi-echo EPI, multi-band EPI and multi-slab echo-volumar imaging pulse sequences, using clinical 3 Tesla MR scanners from two different vendors that were equipped with 64- and 256-channel MR-compatible EEG systems, respectively, and receive only array head coils. Data were collected in 11 healthy controls (3 males, age range 18–70 years) and 13 patients with epilepsy (8 males, age range 21–67 years). Three of the healthy controls were scanned with the 256-channel EEG system, the other subjects were scanned with the 64-channel EEG system. Scalp surface temperature, SNR in occipital cortex and head movement were measured with and without the EEG cap. The degree of artifacts and the ability to identify background activity was assessed by visual analysis by a trained expert in the 64 channel EEG data (7 healthy controls, 13 patients). Results RF induced heating at the surface of the EEG electrodes during a 30-minute scan period with stable temperature prior to scanning did not exceed 1.0° C with either EEG system and any of the pulse sequences used in this study. There was no significant decrease in cortical SNR due to the presence of the EEG cap (p > 0.05). No significant differences in the visually analyzed EEG

  11. Research on the Characteristics of Alzheimer's Disease Using EEG

    Science.gov (United States)

    Ueda, Taishi; Musha, Toshimitsu; Yagi, Tohru

    In this paper, we proposed a new method for diagnosing Alzheimer's disease (AD) on the basis of electroencephalograms (EEG). The method, which is termed Power Variance Function (PVF) method, indicates the variance of the power at each frequency. By using the proposed method, the power of EEG at each frequency was calculated using Wavelet transform, and the corresponding variances were defined as PVF. After the PVF histogram of 55 healthy people was approximated as a Generalized Extreme Value (GEV) distribution, we evaluated the PVF of 22 patients with AD and 25 patients with mild cognitive impairment (MCI). As a result, the values for all AD and MCI subjects were abnormal. In particular, the PVF in the θ band for MCI patients was abnormally high, and the PVF in the α band for AD patients was low.

  12. Computerized EEG and brain imaging studies in untreated schizophrenic patients

    International Nuclear Information System (INIS)

    Miyauchi, Toshiro; Kishimoto, Hideji; Hagimoto, Hiroshi; Fujita, Haruhiro; Tanaka, Kenkichi

    1993-01-01

    We undertook routine EEG, Z-map, CT and PET scans in seven acute untreated schizophrenics. Routine EEGs showed slower activity in only one case. However, the Z-map showed slower activity in all the cases. CT demonstrated brain atrophy in three of the cases, and PET revealed hypofrontality in two, right hypoparietality in four, and both conditions in one case. There was no relation between CT and PET or the Z-map. However, a significant increase in alpha 1 activity was demonstrated on the Z-map in cases who were found to be the parietal type on PET; this was not conspicuous in the frontal type on PET. Moreover, in three of the patients, the Z-map findings were similar to the lesion indicated on PET. (author)

  13. La geometría fractal del EEG

    Directory of Open Access Journals (Sweden)

    Antonio Ibáñez-Molina

    2014-11-01

    Full Text Available El cerebro en acción es un sistema no lineal en el que no existe una relación evidente entre las causas y las consecuencias de un estado determinado: cambios sutiles en un estímulo pueden generar patrones corticales radicalmente distintos. Si las distintas funciones cognitivas surgen de este sistema complejo, es fundamental la introducción de métodos no lineales en el estudio de la relación mente-cerebro. En este artículo hacemos hincapié en la naturaleza fractal del electroencefalograma (EEG y repasamos la relación entre la dimensión fractal del EEG y distintos estados mentales.

  14. EEG differences between the opioid and adrenergic psyhoneuroendocrine rat types

    DEFF Research Database (Denmark)

    Cristea, A; Moldovan, M; Munteanu, A M

    2000-01-01

    (BEA) of the "O" and "A" rat types during restrained wakefulness and anesthesia with Ether and chloral hydrate (CHL). The differentiation of the psyhoneuroendocrine rat types was made using the level of painful sensitivity. 13 hypersensitive "A" and 14 hyposensitive "O" rats were selected from a 91......Our work is based on the hypothesis of the existence of an opioid psychoneuroendocrine type named "O" type (Cristea, 1993), opposed to the well known adrenergic "A" type described by Roseman and Friedman in 1980. In the present study we tested the differences between the background EEG activity...... adult (140 g) male Wistar population using the distribution of the tail retraction time (TRT) during a tail-flick test. The epidural EEG activity, was quantified within the 1-30 Hz band by six numerical parameters: root mean square (RMS), mean spectral frequency (MSF), spectral edge frequency at 95...

  15. EEG controlled occlusion of the internal carotid artery during angiography

    Energy Technology Data Exchange (ETDEWEB)

    Hacke, W.; Zeumer, H.; Ringelstein, E.B.

    1981-09-01

    It became evident in two patients during cerebral angiography that ligation of an internal carotid artery would probably be necessary in the course of a subsequent neurosurgical operation. A balloon catheter was inserted and the internal carotid artery was occluded. A continous EEG recording was made with a Fourier transformed frequency analysis before and during the occlusion; the motor functions of the corresponding side of the body were observed simultaneously on the conscious patient. EEG alterations indicative of cerebral ischemia were not demonstrated in either patient during an occlusion period of 7 min. Unilateral neurosurgical ligation of the common carotid artery and the internal carotid artery was performed on one patient. As predicted no neurological deficit occured.

  16. EEG and Sonic Platforms to Enhance Mindfulness Meditation

    Directory of Open Access Journals (Sweden)

    Caitilin de Berigny

    2016-09-01

    Full Text Available This paper explores interactive applications that encourage mindfulness through sensors and novel input technology. Research in psychology and neuroscience demonstrating the benefits of mindfulness is initiating a new movement in interactive design. As cutting edge technologies become more accessible they are being employed to research and explore the practice of mindfulness. We examine three interactive installation artworks that promote mindfulness. In order to contextualize the interactive artworks discussed we first examine the historical background of the Electroencephalogram (EEG. We then discuss the physiological processes of meditation and the history behind the clinical practice of mindfulness. We show how artists and designers employ EEG sensors, to record the electrical activity of the brain to visualize mindfulness meditation practices. Lastly, we conclude the paper by discussing the future of the three artworks.

  17. Detecting mental EEG properties using detrended fluctuation analysis.

    Science.gov (United States)

    Jiang, Zhaohui; Ning, Yan; An, Bin; Li, Ao; Feng, Huanqing

    2005-01-01

    Based on detrended fluctuation analysis (DFA), we explore the characteristics of multichannel electroencephalogram (EEG), which is recorded from many subjects performing different mental tasks. The results show that mental EEG exhibits long-range power-law correlations by calculating its scaling exponents (alpha), which can reflect the kinds of mental tasks. The scaling exponent of letter-composing is different from that of multiplication especially at positions C3 and C4, and at positions O1 and O2 the scaling exponent of rotation is also different distinctively from that of multiplication. Detrended fluctuation analysis exhibits its robustness against noises in our works. We could benefit more from the results of this paper in designing mental tasks and selecting brain areas in brain-computer interface systems.

  18. EEG INTERFACE MODULE FOR COGNITIVE ASSESSMENT THROUGH NEUROPHYSIOLOGIC TESTS

    Directory of Open Access Journals (Sweden)

    Kundan Lal Verma

    2014-12-01

    Full Text Available The cognitive signal processing is one of the important interdisciplinary field came from areas of life sciences, psychology, psychiatry, engi-neering, mathematics, physics, statistics and many other fields of research. Neurophysiologic tests are utilized to assess and treat brain injury, dementia, neurological conditions, and useful to investigate psychological and psychiatric disorders. This paper presents an ongoing research work on development of EEG interface device based on the principles of cognitive assessments and instrumentation. The method proposed engineering and science of cogni-tive signal processing in case of brain computer in-terface based neurophysiologic tests. The future scope of this study is to build a low cost EEG device for various clinical and pre-clinical applications with specific emphasis to measure the effect of cognitive action on human brain.

  19. EEG changes during sequences of visual and kinesthetic motor imagery.

    Science.gov (United States)

    Stecklow, Marcus Vinicius; Infantosi, Antonio Fernando Catelli; Cagy, Maurício

    2010-08-01

    The evoked cerebral electric response when sequences of complex motor imagery (MI) task are executed several times is still unclear. This work aims at investigating the existence of habituation in the cortical response, more specifically in the alpha band peak of parietal and occipital areas (10-20 international system electroencephalogram, EEG, protocol). The EEG signals were acquired during sequences of MI of volleyball spike movement in kinesthetic and visual modalities and also at control condition. Thirty right-handed male subjects (18 to 40 years) were assigned to either an 'athlete' or a 'non-athlete' group, both containing 15 volunteers. Paired Wilcoxon tests (with alpha=0.05) indicates that sequential MI of complex tasks promotes cortical changes, mainly in the power vicinity of the alpha peak. This finding is more pronounced along the initial trials and also for the athletes during the modality of kinesthetic motor imagery.

  20. Deep Extreme Learning Machine and Its Application in EEG Classification

    Directory of Open Access Journals (Sweden)

    Shifei Ding

    2015-01-01

    Full Text Available Recently, deep learning has aroused wide interest in machine learning fields. Deep learning is a multilayer perceptron artificial neural network algorithm. Deep learning has the advantage of approximating the complicated function and alleviating the optimization difficulty associated with deep models. Multilayer extreme learning machine (MLELM is a learning algorithm of an artificial neural network which takes advantages of deep learning and extreme learning machine. Not only does MLELM approximate the complicated function but it also does not need to iterate during the training process. We combining with MLELM and extreme learning machine with kernel (KELM put forward deep extreme learning machine (DELM and apply it to EEG classification in this paper. This paper focuses on the application of DELM in the classification of the visual feedback experiment, using MATLAB and the second brain-computer interface (BCI competition datasets. By simulating and analyzing the results of the experiments, effectiveness of the application of DELM in EEG classification is confirmed.

  1. Source Localization of Eeg Signals during Muscle Fatigue

    Science.gov (United States)

    Liu, Jing Z.; Yao, Bing; Lewandowski, Beth E.; Karakasis, Chris; Brown, Robert W.; Yue, Guang H.

    2003-10-01

    In this study we determined sources of EEG signals during a fatigue process involving intermittent maximal voluntary contractions (MVCs). In the fatigue motor task, subjects consecutively performed 200 trials of handgrip MVCs, each lasted 2 s, followed by a 5-s rest. In the control task, subjects performed the same task but the rest time was 28 s, and there was also a 5-min rest after each 40 trials so that fatigue effect was minimized. EEG signals were recorded along with handgrip force and EMG data. Current dipole model was applied to determine the signal sources in a three-sphere homogeneous head frame. Effects of fatigue on the signal source were determined. The results showed no significant changes in dipole strength and orientation but significant larger movement ranges in the dipole location during the fatigue process than during the control, indicating fatigue-related rotation of the center of cortical activation.

  2. Video-EEG recording: a four-year clinical audit.

    LENUS (Irish Health Repository)

    O'Rourke, K

    2012-02-03

    In the setting of a regional neurological unit without an epilepsy surgery service as in our case, video-EEG telemetry is undertaken for three main reasons; to investigate whether frequent paroxysmal events represent seizures when there is clinical doubt, to attempt anatomical localization of partial seizures when standard EEG is unhelpful, and to attempt to confirm that seizures are non-epileptic when this is suspected. A clinical audit of all telemetry performed over a four-year period was carried out, in order to determine the clinical utility of this aspect of the service and to determine means of improving effectiveness in the unit. Analysis of the data showed a high rate of negative studies with no attacks recorded. Of the positive studies approximately 50% showed non-epileptic attacks. Strategies for improving the rate of positive investigations are discussed.

  3. Development of a Mobile EEG-based Biometric Authentication System

    DEFF Research Database (Denmark)

    Klonovs, Juris; Petersen, Christoffer Kjeldgaard; Olesen, Henning

    In recent years the need for greater security for storing personal and business data or accessing corporate networks on mobile devices is growing rapidly, and one of the potential solutions is to employ the innovative biometric authentication techniques. This paper presents the development...... of a mobile biometric authentication system based on electroencephalogram (EEG) recordings in combination with already proven technologies such as facial detection and near-field communication (NFC). The overall goal of this work is to fill the gap between mobile web technologies and wireless EEG devices...... and present a mobile prototype system capable of authenticating users based on the uniqueness of their brainwaves. Furthermore, we implement a novel authentication process, which leads the authentication system to be more secure. We also give suggestions for future improvements of the system....

  4. Boxers--computed tomography, EEG, and neurological evaluation

    International Nuclear Information System (INIS)

    Ross, R.J.; Cole, M.; Thompson, J.S.; Kim, K.H.

    1983-01-01

    During the last three years, 40 ex-boxers were examined to determine the effects of boxing in regard to their neurological status and the computed tomographic (CT) appearance of the brain. Thirty-eight of these patients had a CT scan of the brain, and 24 had a complete neurological examination including an EEG. The results demonstrate a significant relationship between the number of bouts fought and CT changes indicating cerebral atrophy. Positive neurological findings were not significantly correlated with the number of bouts. Electroencephalographic abnormalities were significantly correlated with the number of bouts fought. Computed tomography and EEG of the brain should be considered as part of a regular neurological examination for active boxers and, if possible, before and after each match, to detect not only the effects of acute life-threatening brain trauma such as subdural hematomas and brain hemorrhages, but the more subtle and debilitating long-term changes of cerebral atrophy

  5. Convolutive ICA for Spatio-Temporal Analysis of EEG

    DEFF Research Database (Denmark)

    Dyrholm, Mads; Makeig, Scott; Hansen, Lars Kai

    2007-01-01

    We present a new algorithm for maximum likelihood convolutive ICA (cICA) in which sources are unmixed using stable IIR filters determined implicitly by estimating an FIR filter model of the mixing process. By intro- ducing a FIR model for the sources we show how the order of the filters in the co......We present a new algorithm for maximum likelihood convolutive ICA (cICA) in which sources are unmixed using stable IIR filters determined implicitly by estimating an FIR filter model of the mixing process. By intro- ducing a FIR model for the sources we show how the order of the filters...... in the convolutive model can be correctly detected using Bayesian model selection. We demonstrate a framework for deconvolving an EEG ICA subspace. Initial results suggest that in some cases convolutive mixing may be a more realistic model for EEG signals than the instantaneous ICA model....

  6. [EEG spectral characteristics in the dynamics of planned movements].

    Science.gov (United States)

    Aslanian, E V; Kiroĭ, V N; Lazurenko, D M; Bakhtin, O M; Miniaeva, N R

    2014-01-01

    The spectral characteristics of the EEG in 11 healthy right-handed volunteers with no neurological disorders in dynamics of the unusual finger movements of both hands in random rhythm have been investigated. In particular, it is shown that the preparation and execution of voluntary finger movements compared to the rest were accompanied by a reduction level of activation within almost all the surface of cerebral cortex, except for right frontal lobe. It has been experimentally demonstrated that a significant increasing EEG activity of the right frontal area in high-frequency domain power spectrum was independent of the working limb. This might testify the direct participation of this cortical area in the processes of voluntary muscular activity planning, initiation and control.

  7. A Game Player Expertise Level Classification System Using Electroencephalography (EEG

    Directory of Open Access Journals (Sweden)

    Syed Muhammad Anwar

    2017-12-01

    Full Text Available The success and wider adaptability of smart phones has given a new dimension to the gaming industry. Due to the wide spectrum of video games, the success of a particular game depends on how efficiently it is able to capture the end users’ attention. This leads to the need to analyse the cognitive aspects of the end user, that is the game player, during game play. A direct window to see how an end user responds to a stimuli is to look at their brain activity. In this study, electroencephalography (EEG is used to record human brain activity during game play. A commercially available EEG headset is used for this purpose giving fourteen channels of recorded EEG brain activity. The aim is to classify a player as expert or novice using the brain activity as the player indulges in the game play. Three different machine learning classifiers have been used to train and test the system. Among the classifiers, naive Bayes has outperformed others with an accuracy of 88 % , when data from all fourteen EEG channels are used. Furthermore, the activity observed on electrodes is statistically analysed and mapped for brain visualizations. The analysis has shown that out of the available fourteen channels, only four channels in the frontal and occipital brain regions show significant activity. Features of these four channels are then used, and the performance parameters of the four-channel classification are compared to the results of the fourteen-channel classification. It has been observed that support vector machine and the naive Bayes give good classification accuracy and processing time, well suited for real-time applications.

  8. EEG topographies provide subject-specific correlates of motor control

    OpenAIRE

    Pirondini, Elvira; Coscia, Martina; Minguillon, Jesus; Millán, José del R.; Van De Ville, Dimitri; Micera, Silvestro

    2017-01-01

    Electroencephalography (EEG) of brain activity can be represented in terms of dynamically changing topographies (microstates). Notably, spontaneous brain activity recorded at rest can be characterized by four distinctive topographies. Despite their well-established role during resting state, their implication in the generation of motor behavior is debated. Evidence of such a functional role of spontaneous brain activity would provide support for the design of novel and sensitive biomarkers in...

  9. Chronic schizophrenics with positive symptomatology have shortened EEG microstate durations

    OpenAIRE

    Strelets, V.; Faber, P. L.; Golikova, J.; Novototsky-Vlasov, V.; Koenig, T.; Gianotti, L. R. R.; Gruzelier, J. H.; Lehmann, D.

    2003-01-01

    In young, first-episode, never-treated schizophrenics compared with controls, (a) generally shorter durations of EEG microstates were reported (Koukkou et al., Brain Topogr 6 (1994) 251; Kinoshita et al., Psychiatry Res Neuroimaging 83 (1998) 58), and (b) specifically, shorter duration of a particular class of microstates (Koenig et al., Eur Arch Psychiatry Clin Neurosci 249 (1999) 205). We now examined whether older, chronic schizophrenic patients with positive symptomatology also show these...

  10. Neural Mechanisms of Cognitive Dissonance (Revised): An EEG Study

    OpenAIRE

    Colosio, Marco; Shestakova, Anna; Nikulin, Vadim V.; Blagovechtchenski, Evgeny; Klucharev, Vasily

    2017-01-01

    Cognitive dissonance theory suggests that our preferences are modulated by the mere act of choosing. A choice between two similarly valued alternatives creates psychological tension (cognitive dissonance) that is reduced by a postdecisional reevaluation of the alternatives. We measured EEG of human subjects during rest and free-choice paradigm. Our study demonstrates that choices associated with stronger cognitive dissonance trigger a larger negative frontocentral evoked response similar to e...

  11. EFFICACY OF ACTIVATION PROCEDURES TO ILLUSTRATE EEG CHANGES IN EPILEPSY

    Directory of Open Access Journals (Sweden)

    Rimpy Bhuyan

    2017-04-01

    Full Text Available BACKGROUND EEG or Electroencephalogram, which is the most important diagnostic procedure to evaluate Epilepsy patients, may sometimes fall short of accurate sensitivity and may require few Activation Procedures such as ‘Hyperventilation’ and ‘Sleep’ to bring out the active changes of an Epileptic brain. The present study was done with the aim of knowing the efficacy of such Activation Procedures like ‘Hyperventilation’ and ‘Sleep’ in illustrating the EEG wave pattern changes of an Epileptic brain during the interictal period. MATERIALS AND METHODS The present study was done in the Department of Physiology in association with the Department of Neurology, Assam Medical College & Hospital, Dibrugarh, Assam from June 2014 to May 2015. ‘113’ clinically diagnosed cases of Epilepsy were studied and analysed through Electroencephalogram using the internationally accepted 10-20 electrode placement method. Hyperventilation was used in 28 Epilepsy cases and Sleep was used in 14 Epilepsy cases. History & Physical examination findings were recorded in a Proforma. Chi-square analysis was done through GraphPad Prism 6 software to assess the significance of the activation procedures used. RESULTS Our study found that EEG of 42 cases out of the total 113 cases required Activation Procedures to elicit the wave pattern changes of the Epileptic brain. Hyperventilation was helpful in adult age group and sleep was useful in children age group. Hyperventilation had overall 53.57% sensitivity in detecting Epilepsy, and Sleep had 64.29% sensitivity in detecting Epilepsy. Hyperventilation was specifically helpful to elicit absence seizures where it had 75% sensitivity. CONCLUSION The sensitivity of EEG in detecting Epilepsy can thus be increased by using activation procedures like sleep & Hyperventilation to ensure that no epilepsy cases are missed out in diagnosis & treatment.

  12. Decoding spatial attention with EEG and virtual acoustic space.

    Science.gov (United States)

    Dong, Yue; Raif, Kaan E; Determan, Sarah C; Gai, Yan

    2017-11-01

    Decoding spatial attention based on brain signals has wide applications in brain-computer interface (BCI). Previous BCI systems mostly relied on visual patterns or auditory stimulation (e.g., loudspeakers) to evoke synchronous brain signals. There would be difficulties to cover a large range of spatial locations with such a stimulation protocol. The present study explored the possibility of using virtual acoustic space and a visual-auditory matching paradigm to overcome this issue. The technique has the flexibility of generating sound stimulation from virtually any spatial location. Brain signals of eight human subjects were obtained with a 32-channel Electroencephalogram (EEG). Two amplitude-modulated noise or speech sentences carrying distinct spatial information were presented concurrently. Each sound source was tagged with a unique modulation phase so that the phase of the recorded EEG signals indicated the sound being attended to. The phase-tagged sound was further filtered with head-related transfer functions to create the sense of virtual space. Subjects were required to pay attention to the sound source that best matched the location of a visual target. For all the subjects, the phase of a single sound could be accurately reflected over the majority of electrodes based on EEG responses of 90 s or less. The electrodes providing significant decoding performance on auditory attention were fewer and may require longer EEG responses. The reliability and efficiency of decoding with a single electrode varied with subjects. Overall, the virtual acoustic space protocol has the potential of being used in practical BCI systems. © 2017 Saint Louis University. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  13. Behavioral and EEG evidence for auditory memory suppression

    Directory of Open Access Journals (Sweden)

    Maya Elizabeth Cano

    2016-03-01

    Full Text Available The neural basis of motivated forgetting using the Think/No-Think (TNT paradigm is receiving increased attention with a particular focus on the mechanisms that enable memory suppression. However, most TNT studies have been limited to the visual domain. To assess whether and to what extent direct memory suppression extends across sensory modalities, we examined behavioral and electroencephalographic (EEG effects of auditory Think/No-Think in healthy young adults by adapting the TNT paradigm to the auditory modality. Behaviorally, suppression of memory strength was indexed by prolonged response times during the retrieval of subsequently remembered No-Think words. We examined task-related EEG activity of both attempted memory retrieval and inhibition of a previously learned target word during the presentation of its paired associate. Event-related EEG responses revealed two main findings: 1 a centralized Think > No-Think positivity during auditory word presentation (from approximately 0-500ms, and 2 a sustained Think positivity over parietal electrodes beginning at approximately 600ms reflecting the memory retrieval effect which was significantly reduced for No-Think words. In addition, word-locked theta (4-8 Hz power was initially greater for No-Think compared to Think during auditory word presentation over fronto-central electrodes. This was followed by a posterior theta increase indexing successful memory retrieval in the Think condition.The observed event-related potential pattern and theta power analysis are similar to that reported in visual Think/No-Think studies and support a modality non-specific mechanism for memory inhibition. The EEG data also provide evidence supporting differing roles and time courses of frontal and parietal regions in the flexible control of auditory memory.

  14. Sleep in the human hippocampus: a stereo-EEG study.

    Directory of Open Access Journals (Sweden)

    Fabio Moroni

    Full Text Available BACKGROUND: There is compelling evidence indicating that sleep plays a crucial role in the consolidation of new declarative, hippocampus-dependent memories. Given the increasing interest in the spatiotemporal relationships between cortical and hippocampal activity during sleep, this study aimed to shed more light on the basic features of human sleep in the hippocampus. METHODOLOGY/PRINCIPAL FINDINGS: We recorded intracerebral stereo-EEG directly from the hippocampus and neocortical sites in five epileptic patients undergoing presurgical evaluations. The time course of classical EEG frequency bands during the first three NREM-REM sleep cycles of the night was evaluated. We found that delta power shows, also in the hippocampus, the progressive decrease across sleep cycles, indicating that a form of homeostatic regulation of delta activity is present also in this subcortical structure. Hippocampal sleep was also characterized by: i a lower relative power in the slow oscillation range during NREM sleep compared to the scalp EEG; ii a flattening of the time course of the very low frequencies (up to 1 Hz across sleep cycles, with relatively high levels of power even during REM sleep; iii a decrease of power in the beta band during REM sleep, at odds with the typical increase of power in the cortical recordings. CONCLUSIONS/SIGNIFICANCE: Our data imply that cortical slow oscillation is attenuated in the hippocampal structures during NREM sleep. The most peculiar feature of hippocampal sleep is the increased synchronization of the EEG rhythms during REM periods. This state of resonance may have a supportive role for the processing/consolidation of memory.

  15. Toward a direct measure of video quality perception using EEG.

    Science.gov (United States)

    Scholler, Simon; Bosse, Sebastian; Treder, Matthias Sebastian; Blankertz, Benjamin; Curio, Gabriel; Müller, Klaus-Robert; Wiegand, Thomas

    2012-05-01

    An approach to the direct measurement of perception of video quality change using electroencephalography (EEG) is presented. Subjects viewed 8-s video clips while their brain activity was registered using EEG. The video signal was either uncompressed at full length or changed from uncompressed to a lower quality level at a random time point. The distortions were introduced by a hybrid video codec. Subjects had to indicate whether they had perceived a quality change. In response to a quality change, a positive voltage change in EEG (the so-called P3 component) was observed at latency of about 400-600 ms for all subjects. The voltage change positively correlated with the magnitude of the video quality change, substantiating the P3 component as a graded neural index of the perception of video quality change within the presented paradigm. By applying machine learning techniques, we could classify on a single-trial basis whether a subject perceived a quality change. Interestingly, some video clips wherein changes were missed (i.e., not reported) by the subject were classified as quality changes, suggesting that the brain detected a change, although the subject did not press a button. In conclusion, abrupt changes of video quality give rise to specific components in the EEG that can be detected on a single-trial basis. Potentially, a neurotechnological approach to video assessment could lead to a more objective quantification of quality change detection, overcoming the limitations of subjective approaches (such as subjective bias and the requirement of an overt response). Furthermore, it allows for real-time applications wherein the brain response to a video clip is monitored while it is being viewed.

  16. Neurobiological correlates of EMDR monitoring - an EEG study.

    Science.gov (United States)

    Pagani, Marco; Di Lorenzo, Giorgio; Verardo, Anna Rita; Nicolais, Giampaolo; Monaco, Leonardo; Lauretti, Giada; Russo, Rita; Niolu, Cinzia; Ammaniti, Massimo; Fernandez, Isabel; Siracusano, Alberto

    2012-01-01

    Eye Movement Desensitization and Reprocessing (EMDR) is a recognized first-line treatment for psychological trauma. However its neurobiological bases have yet to be fully disclosed. Electroencephalography (EEG) was used to fully monitor neuronal activation throughout EMDR sessions including the autobiographical script. Ten patients with major psychological trauma were investigated during their first EMDR session (T0) and during the last one performed after processing the index trauma (T1). Neuropsychological tests were administered at the same time. Comparisons were performed between EEGs of patients at T0 and T1 and between EEGs of patients and 10 controls who underwent the same EMDR procedure at T0. Connectivity analyses were carried out by lagged phase synchronization. During bilateral ocular stimulation (BS) of EMDR sessions EEG showed a significantly higher activity on the orbito-frontal, prefrontal and anterior cingulate cortex in patients at T0 shifting towards left temporo-occipital regions at T1. A similar trend was found for autobiographical script with a higher firing in fronto-temporal limbic regions at T0 moving to right temporo-occipital cortex at T1. The comparisons between patients and controls confirmed the maximal activation in the limbic cortex of patients occurring before trauma processing. Connectivity analysis showed decreased pair-wise interactions between prefrontal and cingulate cortex during BS in patients as compared to controls and between fusiform gyrus and visual cortex during script listening in patients at T1 as compared to T0. These changes correlated significantly with those occurring in neuropsychological tests. The ground-breaking methodology enabled our study to image for the first time the specific activations associated with the therapeutic actions typical of EMDR protocol. The findings suggest that traumatic events are processed at cognitive level following successful EMDR therapy, thus supporting the evidence of distinct

  17. Neurobiological correlates of EMDR monitoring - an EEG study.

    Directory of Open Access Journals (Sweden)

    Marco Pagani

    Full Text Available BACKGROUND: Eye Movement Desensitization and Reprocessing (EMDR is a recognized first-line treatment for psychological trauma. However its neurobiological bases have yet to be fully disclosed. METHODS: Electroencephalography (EEG was used to fully monitor neuronal activation throughout EMDR sessions including the autobiographical script. Ten patients with major psychological trauma were investigated during their first EMDR session (T0 and during the last one performed after processing the index trauma (T1. Neuropsychological tests were administered at the same time. Comparisons were performed between EEGs of patients at T0 and T1 and between EEGs of patients and 10 controls who underwent the same EMDR procedure at T0. Connectivity analyses were carried out by lagged phase synchronization. RESULTS: During bilateral ocular stimulation (BS of EMDR sessions EEG showed a significantly higher activity on the orbito-frontal, prefrontal and anterior cingulate cortex in patients at T0 shifting towards left temporo-occipital regions at T1. A similar trend was found for autobiographical script with a higher firing in fronto-temporal limbic regions at T0 moving to right temporo-occipital cortex at T1. The comparisons between patients and controls confirmed the maximal activation in the limbic cortex of patients occurring before trauma processing. Connectivity analysis showed decreased pair-wise interactions between prefrontal and cingulate cortex during BS in patients as compared to controls and between fusiform gyrus and visual cortex during script listening in patients at T1 as compared to T0. These changes correlated significantly with those occurring in neuropsychological tests. CONCLUSIONS: The ground-breaking methodology enabled our study to image for the first time the specific activations associated with the therapeutic actions typical of EMDR protocol. The findings suggest that traumatic events are processed at cognitive level following successful

  18. Neurobiological Correlates of EMDR Monitoring – An EEG Study

    Science.gov (United States)

    Pagani, Marco; Di Lorenzo, Giorgio; Verardo, Anna Rita; Nicolais, Giampaolo; Monaco, Leonardo; Lauretti, Giada; Russo, Rita; Niolu, Cinzia; Ammaniti, Massimo; Fernandez, Isabel; Siracusano, Alberto

    2012-01-01

    Background Eye Movement Desensitization and Reprocessing (EMDR) is a recognized first-line treatment for psychological trauma. However its neurobiological bases have yet to be fully disclosed. Methods Electroencephalography (EEG) was used to fully monitor neuronal activation throughout EMDR sessions including the autobiographical script. Ten patients with major psychological trauma were investigated during their first EMDR session (T0) and during the last one performed after processing the index trauma (T1). Neuropsychological tests were administered at the same time. Comparisons were performed between EEGs of patients at T0 and T1 and between EEGs of patients and 10 controls who underwent the same EMDR procedure at T0. Connectivity analyses were carried out by lagged phase synchronization. Results During bilateral ocular stimulation (BS) of EMDR sessions EEG showed a significantly higher activity on the orbito-frontal, prefrontal and anterior cingulate cortex in patients at T0 shifting towards left temporo-occipital regions at T1. A similar trend was found for autobiographical script with a higher firing in fronto-temporal limbic regions at T0 moving to right temporo-occipital cortex at T1. The comparisons between patients and controls confirmed the maximal activation in the limbic cortex of patients occurring before trauma processing. Connectivity analysis showed decreased pair-wise interactions between prefrontal and cingulate cortex during BS in patients as compared to controls and between fusiform gyrus and visual cortex during script listening in patients at T1 as compared to T0. These changes correlated significantly with those occurring in neuropsychological tests. Conclusions The ground-breaking methodology enabled our study to image for the first time the specific activations associated with the therapeutic actions typical of EMDR protocol. The findings suggest that traumatic events are processed at cognitive level following successful EMDR therapy, thus

  19. Continuous EEG-SEP monitoring in severe brain injury.

    Science.gov (United States)

    Amantini, A; Fossi, S; Grippo, A; Innocenti, P; Amadori, A; Bucciardini, L; Cossu, C; Nardini, C; Scarpelli, S; Roma, V; Pinto, F

    2009-04-01

    To monitor acute brain injury in the neurological intensive care unit (NICU), we used EEG and somatosensory evoked potentials (SEP) in combination to achieve more accuracy in detecting brain function deterioration. Sixty-eight patients (head trauma and intracranial hemorrhage; GCSSEP and intracranial pressure monitoring (ICP). Fifty-five patients were considered "stable" or improving, considering the GCS and CT scan: in this group, SEP didn't show significant changes. Thirteen patients showed neurological deteriorations and, in all patients, cortical SEP showed significant alterations (amplitude decrease>50% often till complete disappearance). SEP deterioration anticipated ICP increase in 30%, was contemporary in 38%, and followed ICP increase in 23%. Considering SEP and ICP in relation to clinical course, all patients but one with ICP less than 20 mmHg were stable, while the three patients with ICP greater than 40 mmHg all died. Among the 26 patients with ICP of 20-40 mmHg, 17 were stable, while nine showed clinical and neurophysiological deterioration. Thus, there is a range of ICP values (20-40 mmHg) were ICP is scarcely indicative of clinical deterioration, rather it is the SEP changes that identify brain function deterioration. Therefore, SEP have a twofold interest with respect to ICP: their changes can precede an ICP increase and they can constitute a complementary tool to interpret ICP trends. It has been very important to associate SEP and EEG: about 60% of our patients were deeply sedated and, because of their relative insensitivity to anesthetics, only SEP allowed us to monitor brain damage evolution when EEG was scarcely valuable. We observed 3% of nonconvulsive status epilepticus compared to 18% of neurological deterioration. If the aim of neurophysiological monitoring is to "detect and protect", it may not be limited to detecting seizures, rather it should be able to identify brain deterioration, so we propose the combined monitoring of EEG with SEP.

  20. A Customizable and Expandable Electroencephalography (EEG) Data Collection System

    Science.gov (United States)

    2016-03-01

    monitoring the brain’s electrical activity, known as electroencephalography (EEG). Studies have shown encouraging results in the areas of medicine and...devices, including Emotiv Systems3 and Advanced Brain Monitoring,4 as well as open source alternatives such as OpenBCI.5 These products generally...channels were tested and the results were the same. (a) Gain = 1 (b) Gain = 2 Fig. 5 Measured output with gain = a) 1, b) 2, c) 12, and d

  1. Special Electrophysiological Tests: Brain Spiking, EEG Spectral Coherence

    Science.gov (United States)

    1983-01-01

    Mental Sciences 9TIC E-~ MAY (In Press) Handbook of Diagnostic Procedifre, Spectrum Pblications, Jamaica , New York. > This wk was pa -tially supported...likelihood is sufficiently small, then we reject the hypothesis that an EEG record containing N spikes in a time t is a normal record, - ,- - Flor several...significantly from zero, one may concl de that the two signal processes in question are related through ,o linear transformation over the spectral

  2. Seizure classification in EEG signals utilizing Hilbert-Huang transform

    OpenAIRE

    Oweis, Rami J; Abdulhay, Enas W

    2011-01-01

    Abstract Background Classification method capable of recognizing abnormal activities of the brain functionality are either brain imaging or brain signal analysis. The abnormal activity of interest in this study is characterized by a disturbance caused by changes in neuronal electrochemical activity that results in abnormal synchronous discharges. The method aims at helping physicians discriminate between healthy and seizure electroencephalographic (EEG) signals. Method Discrimination in this ...

  3. EEG criteria predictive of complicated evolution in idiopathic rolandic epilepsy.

    Science.gov (United States)

    Massa, R; de Saint-Martin, A; Carcangiu, R; Rudolf, G; Seegmuller, C; Kleitz, C; Metz-Lutz, M N; Hirsch, E; Marescaux, C

    2001-09-25

    Although so-called "benign" epilepsy with centrotemporal spikes (BECTS) always has an excellent prognosis with regard to seizure remission, behavioral problems and cognitive dysfunctions may sometimes develop in its course. To search for clinical or EEG markers allowing early detection of patients prone to such complications, the authors conducted a prospective study in a cohort of unselected patients with BECTS. In 35 children with BECTS, academic, familial, neurologic, neuropsychological, and wake and sleep EEG evaluations were repeated every 6 to 12 months from the beginning of the seizure disorder up to complete recovery. In 25 of 35 patients (72%), behavioral and intellectual functioning remained unimpaired. In 10 of 35 patients (28%), educational performance and familial maladjustment occurred. These sociofamilial problems were correlated with impulsivity, learning difficulties, attention disorders, and minor (7/35 cases, 20%) or serious (3/35 cases, 8%) auditory-verbal or visual-spatial deficits. Worsening phases started 2 to 36 months after onset and persisted for 9 to 39 months. Occurrence of atypical evolutions was significantly correlated with five qualitative and one quantitative interictal EEG pattern: intermittent slow-wave focus, multiple asynchronous spike-wave foci, long spike-wave clusters, generalized 3-c/s "absence-like" spike-wave discharges, conjunction of interictal paroxysms with negative or positive myoclonia, and abundance of interictal abnormalities during wakefulness and sleep. Clinical deterioration was not linked with seizure characteristics or treatment. Different combinations of at least three of six distinctive interictal EEG patterns and their long-lasting (> or =6-month) persistence seem to be the hallmarks of patients with BECTS at risk for neuropsychological impairments.

  4. Behavioral and EEG Evidence for Auditory Memory Suppression.

    Science.gov (United States)

    Cano, Maya E; Knight, Robert T

    2016-01-01

    The neural basis of motivated forgetting using the Think/No-Think (TNT) paradigm is receiving increased attention with a particular focus on the mechanisms that enable memory suppression. However, most TNT studies have been limited to the visual domain. To assess whether and to what extent direct memory suppression extends across sensory modalities, we examined behavioral and electroencephalographic (EEG) effects of auditory TNT in healthy young adults by adapting the TNT paradigm to the auditory modality. Behaviorally, suppression of memory strength was indexed by prolonged response time (RTs) during the retrieval of subsequently remembered No-Think words. We examined task-related EEG activity of both attempted memory retrieval and inhibition of a previously learned target word during the presentation of its paired associate. Event-related EEG responses revealed two main findings: (1) a centralized Think > No-Think positivity during auditory word presentation (from approximately 0-500 ms); and (2) a sustained Think positivity over parietal electrodes beginning at approximately 600 ms reflecting the memory retrieval effect which was significantly reduced for No-Think words. In addition, word-locked theta (4-8 Hz) power was initially greater for No-Think compared to Think during auditory word presentation over fronto-central electrodes. This was followed by a posterior theta increase indexing successful memory retrieval in the Think condition. The observed event-related potential pattern and theta power analysis are similar to that reported in visual TNT studies and support a modality non-specific mechanism for memory inhibition. The EEG data also provide evidence supporting differing roles and time courses of frontal and parietal regions in the flexible control of auditory memory.

  5. EEG alpha sensitization in individualized homeopathic treatment of fibromyalgia.

    Science.gov (United States)

    Bell, Iris R; Lewis, Daniel A; Lewis, Sabrina E; Schwartz, Gary E; Brooks, Audrey J; Scott, Anne; Baldwin, Carol M

    2004-09-01

    Fibromyalgia (FM) patients show evidence of sensitizability in pain pathways and electroencephalographic (EEG) alterations. One proposed mechanism for the claimed effects of homeopathy, a form of complementary medicine used for FM, is time-dependent sensitization (TDS, progressive amplification) of host responses. This study examined possible sensitization-related changes in EEG relative alpha magnitude during a clinical trial of homeopathy in FM. A 4-month randomized, placebo-controlled double-blind trial of daily orally administered individualized homeopathy in physician-confirmed FM, with an additional 2-month optional crossover phase, included three laboratory sessions, at baseline, 3 and 6 months (N = 48, age 49.2 +/- 9.8 years, 94% women). Nineteen leads of EEG relative alpha magnitude at rest and during olfactory administration of treatment and control solutions were evaluated in each session. After 3 months, the active treatment group significantly increased, while the placebo group decreased, in global alpha-1 and alpha-2 during bottle sniffs over sessions. At 6 months, the subset of active patients who stayed on active continued to increase, while the active-switch subgroup reversed direction in alpha magnitude. Groups did not differ in resting alpha. Consistent with the TDS hypothesis, sniff alpha-1 and alpha-2 increases at 6 months versus baseline correlated with total amount of time on active remedy over all subjects (r = 0.45, p = .003), not with dose changes or clinical outcomes in the active group. The findings suggest initiation of TDS in relative EEG alpha magnitude by daily oral administration of active homeopathic medicines versus placebo, with laboratory elicitation by temporolimbic olfactory stimulation or sniffing.

  6. EEG-microstate dependent emergence of perceptual awareness

    Directory of Open Access Journals (Sweden)

    Juliane eBritz

    2014-05-01

    Full Text Available We investigated whether the differences in perceptual awareness for stimuli at the threshold of awareness can arise from different global brain states before stimulus onset indexed by the EEG microstate. We used a metacontrast backward masking paradigm in which subjects had to discriminate between two weak stimuli and obtained measures of accuracy and awareness while their EEG was recorded from 256 channels. Comparing correctly identified targets with and without awareness allowed us to contrast differences in awareness while keeping performance constant for identical physical stimuli. Two distinct pre-stimulus scalp potential fields (microstate maps dissociated correct identification with and without awareness, and their estimated intracranial generators were stronger in primary visual cortex before correct identification without awareness. This difference in activity cannot be explained by differences in alpha power or phase which were less reliably linked with differential pre-stimulus activation of primary visual cortex. Our results shed a new light on the function of pre-stimulus activity in early visual cortex in visual awareness and emphasize the importance of trial-by-trials analysis of the spatial configuration of the scalp potential field identified with multichannel EEG.

  7. Blind Source Separation of Event-Related EEG/MEG.

    Science.gov (United States)

    Metsomaa, Johanna; Sarvas, Jukka; Ilmoniemi, Risto Juhani

    2017-09-01

    Blind source separation (BSS) can be used to decompose complex electroencephalography (EEG) or magnetoencephalography data into simpler components based on statistical assumptions without using a physical model. Applications include brain-computer interfaces, artifact removal, and identifying parallel neural processes. We wish to address the issue of applying BSS to event-related responses, which is challenging because of nonstationary data. We introduce a new BSS approach called momentary-uncorrelated component analysis (MUCA), which is tailored for event-related multitrial data. The method is based on approximate joint diagonalization of multiple covariance matrices estimated from the data at separate latencies. We further show how to extend the methodology for autocovariance matrices and how to apply BSS methods suitable for piecewise stationary data to event-related responses. We compared several BSS approaches by using simulated EEG as well as measured somatosensory and transcranial magnetic stimulation (TMS) evoked EEG. Among the compared methods, MUCA was the most tolerant one to noise, TMS artifacts, and other challenges in the data. With measured somatosensory data, over half of the estimated components were found to be similar by MUCA and independent component analysis. MUCA was also stable when tested with several input datasets. MUCA is based on simple assumptions, and the results suggest that MUCA is robust with nonideal data. Event-related responses and BSS are valuable and popular tools in neuroscience. Correctly designed BSS is an efficient way of identifying artifactual and neural processes from nonstationary event-related data.

  8. EEG and MEG Data Analysis in SPM8

    Directory of Open Access Journals (Sweden)

    Vladimir Litvak

    2011-01-01

    Full Text Available SPM is a free and open source software written in MATLAB (The MathWorks, Inc.. In addition to standard M/EEG preprocessing, we presently offer three main analysis tools: (i statistical analysis of scalp-maps, time-frequency images, and volumetric 3D source reconstruction images based on the general linear model, with correction for multiple comparisons using random field theory; (ii Bayesian M/EEG source reconstruction, including support for group studies, simultaneous EEG and MEG, and fMRI priors; (iii dynamic causal modelling (DCM, an approach combining neural modelling with data analysis for which there are several variants dealing with evoked responses, steady state responses (power spectra and cross-spectra, induced responses, and phase coupling. SPM8 is integrated with the FieldTrip toolbox , making it possible for users to combine a variety of standard analysis methods with new schemes implemented in SPM and build custom analysis tools using powerful graphical user interface (GUI and batching tools.

  9. Semi-automatic sleep EEG scoring based on the hypnospectrogram.

    Science.gov (United States)

    Koupparis, Andreas M; Kokkinos, Vasileios; Kostopoulos, George K

    2013-10-25

    Sleep EEG organization is revealed by sleep scoring, a time-consuming process based on strictly defined visual criteria. We explore the possibility of sleep scoring using the whole-night time-frequency analysis, termed hypnospectrogram, with a computer-assisted K-means clustering method. Hypnograms were derived from 10 whole-night sleep EEG recordings using either standard visual scoring under the Rechtshaffen and Kales criteria or semi-automated analysis of the hypnospectrogram derived from a single EEG electrode. We measured substantial agreement between the two approaches with Cohen's kappa considering all 7 stages at 0.61. A number of existing automated procedures have reached the level of human inter-rater agreement using the standard criteria. However, our approach offers the scorer the opportunity to exploit the information-rich graphic representation of the whole night sleep upon which the automated method works. This work suggests that the hypnospectrogram can be used as an objective graphical representation of sleep architecture upon which sleep scoring can be performed with computer-assisted methods. Copyright © 2013. Published by Elsevier B.V.

  10. Plethysmogram and EEG: Effects of Music and Voice Sound

    Science.gov (United States)

    Miao, Tiejun; Oyama-Higa, Mayumi; Sato, Sadaka; Kojima, Junji; Lin, Juan; Reika, Sato

    2011-06-01

    We studied a relation of chaotic dynamics of finger plethysmogram to complexity of high cerebral center in both theoretical and experimental approaches. We proposed a mathematical model to describe emergence of chaos in finger tip pulse wave, which gave a theoretical prediction indicating increased chaoticity in higher cerebral center leading to an increase of chaos dynamics in plethysmograms. We designed an experiment to observe scalp-EEG and finger plethysmogram using two mental tasks to validate the relationship. We found that scalp-EEG showed an increase of the largest Lyapunov exponents (LLE) during speaking certain voices. Topographical scalp map of LLE showed enhanced arise around occipital and right cerebral area. Whereas there was decreasing tendency during listening music, where LLE scalp map revealed a drop around center cerebral area. The same tendency was found for LLE obtained from finger plethysmograms as ones of EEG under either speaking or listening tasks. The experiment gave results that agreed well with the theoretical relation derived from our proposed model.

  11. EEG potentials predict upcoming emergency brakings during simulated driving.

    Science.gov (United States)

    Haufe, Stefan; Treder, Matthias S; Gugler, Manfred F; Sagebaum, Max; Curio, Gabriel; Blankertz, Benjamin

    2011-10-01

    Emergency braking assistance has the potential to prevent a large number of car crashes. State-of-the-art systems operate in two stages. Basic safety measures are adopted once external sensors indicate a potential upcoming crash. If further activity at the brake pedal is detected, the system automatically performs emergency braking. Here, we present the results of a driving simulator study indicating that the driver's intention to perform emergency braking can be detected based on muscle activation and cerebral activity prior to the behavioural response. Identical levels of predictive accuracy were attained using electroencephalography (EEG), which worked more quickly than electromyography (EMG), and using EMG, which worked more quickly than pedal dynamics. A simulated assistance system using EEG and EMG was found to detect emergency brakings 130 ms earlier than a system relying only on pedal responses. At 100 km h(-1) driving speed, this amounts to reducing the braking distance by 3.66 m. This result motivates a neuroergonomic approach to driving assistance. Our EEG analysis yielded a characteristic event-related potential signature that comprised components related to the sensory registration of a critical traffic situation, mental evaluation of the sensory percept and motor preparation. While all these components should occur often during normal driving, we conjecture that it is their characteristic spatio-temporal superposition in emergency braking situations that leads to the considerable prediction performance we observed.

  12. Progress in EEG-Based Brain Robot Interaction Systems

    Science.gov (United States)

    Li, Mengfan; Niu, Linwei; Xian, Bin; Zeng, Ming; Chen, Genshe

    2017-01-01

    The most popular noninvasive Brain Robot Interaction (BRI) technology uses the electroencephalogram- (EEG-) based Brain Computer Interface (BCI), to serve as an additional communication channel, for robot control via brainwaves. This technology is promising for elderly or disabled patient assistance with daily life. The key issue of a BRI system is to identify human mental activities, by decoding brainwaves, acquired with an EEG device. Compared with other BCI applications, such as word speller, the development of these applications may be more challenging since control of robot systems via brainwaves must consider surrounding environment feedback in real-time, robot mechanical kinematics, and dynamics, as well as robot control architecture and behavior. This article reviews the major techniques needed for developing BRI systems. In this review article, we first briefly introduce the background and development of mind-controlled robot technologies. Second, we discuss the EEG-based brain signal models with respect to generating principles, evoking mechanisms, and experimental paradigms. Subsequently, we review in detail commonly used methods for decoding brain signals, namely, preprocessing, feature extraction, and feature classification, and summarize several typical application examples. Next, we describe a few BRI applications, including wheelchairs, manipulators, drones, and humanoid robots with respect to synchronous and asynchronous BCI-based techniques. Finally, we address some existing problems and challenges with future BRI techniques. PMID:28484488

  13. Identifying Objective EEG Based Markers of Linear Vection in Depth

    Directory of Open Access Journals (Sweden)

    Stephen Palmisano

    2016-08-01

    Full Text Available This proof-of-concept study investigated whether a time-frequency EEG approach could be used to examine vection (i.e., illusions of self-motion. In the main experiment, we compared the event-related spectral perturbation (ERSP data of 10 observers during and directly after repeated exposures to two different types of optic flow display (each was 35° wide by 29° high and provided 20 s of motion stimulation. Displays consisted of either a vection display (which simulated constant velocity forward self-motion in depth or a control display (a spatially scrambled version of the vection display. ERSP data were decomposed using time-frequency Principal Components Analysis (t-f PCA. We found an increase in 10 Hz alpha activity, peaking some 14 s after display motion commenced, which was positively associated with stronger vection ratings. This followed decreases in beta activity, and was also followed by a decrease in delta activity; these decreases in EEG amplitudes were negatively related to the intensity of the vection experience. After display motion ceased, a series of increases in the alpha band also correlated with vection intensity, and appear to reflect vection- and/or motion-aftereffects, as well as later cognitive preparation for reporting the strength of the vection experience. Overall, these findings provide support for the notion that EEG can be used to provide objective markers of changes in both vection status (i.e., vection/no vection and vection strength.

  14. EEG potentials predict upcoming emergency brakings during simulated driving

    Science.gov (United States)

    Haufe, Stefan; Treder, Matthias S.; Gugler, Manfred F.; Sagebaum, Max; Curio, Gabriel; Blankertz, Benjamin

    2011-10-01

    Emergency braking assistance has the potential to prevent a large number of car crashes. State-of-the-art systems operate in two stages. Basic safety measures are adopted once external sensors indicate a potential upcoming crash. If further activity at the brake pedal is detected, the system automatically performs emergency braking. Here, we present the results of a driving simulator study indicating that the driver's intention to perform emergency braking can be detected based on muscle activation and cerebral activity prior to the behavioural response. Identical levels of predictive accuracy were attained using electroencephalography (EEG), which worked more quickly than electromyography (EMG), and using EMG, which worked more quickly than pedal dynamics. A simulated assistance system using EEG and EMG was found to detect emergency brakings 130 ms earlier than a system relying only on pedal responses. At 100 km h-1 driving speed, this amounts to reducing the braking distance by 3.66 m. This result motivates a neuroergonomic approach to driving assistance. Our EEG analysis yielded a characteristic event-related potential signature that comprised components related to the sensory registration of a critical traffic situation, mental evaluation of the sensory percept and motor preparation. While all these components should occur often during normal driving, we conjecture that it is their characteristic spatio-temporal superposition in emergency braking situations that leads to the considerable prediction performance we observed.

  15. Progress in EEG-Based Brain Robot Interaction Systems

    Directory of Open Access Journals (Sweden)

    Xiaoqian Mao

    2017-01-01

    Full Text Available The most popular noninvasive Brain Robot Interaction (BRI technology uses the electroencephalogram- (EEG- based Brain Computer Interface (BCI, to serve as an additional communication channel, for robot control via brainwaves. This technology is promising for elderly or disabled patient assistance with daily life. The key issue of a BRI system is to identify human mental activities, by decoding brainwaves, acquired with an EEG device. Compared with other BCI applications, such as word speller, the development of these applications may be more challenging since control of robot systems via brainwaves must consider surrounding environment feedback in real-time, robot mechanical kinematics, and dynamics, as well as robot control architecture and behavior. This article reviews the major techniques needed for developing BRI systems. In this review article, we first briefly introduce the background and development of mind-controlled robot technologies. Second, we discuss the EEG-based brain signal models with respect to generating principles, evoking mechanisms, and experimental paradigms. Subsequently, we review in detail commonly used methods for decoding brain signals, namely, preprocessing, feature extraction, and feature classification, and summarize several typical application examples. Next, we describe a few BRI applications, including wheelchairs, manipulators, drones, and humanoid robots with respect to synchronous and asynchronous BCI-based techniques. Finally, we address some existing problems and challenges with future BRI techniques.

  16. Hyperspherical Manifold for EEG Signals of Epileptic Seizures

    Directory of Open Access Journals (Sweden)

    Tahir Ahmad

    2012-01-01

    Full Text Available The mathematical modelling of EEG signals of epileptic seizures presents a challenge as seizure data is erratic, often with no visible trend. Limitations in existing models indicate a need for a generalized model that can be used to analyze seizures without the need for apriori information, whilst minimizing the loss of signal data due to smoothing. This paper utilizes measure theory to design a discrete probability measure that reformats EEG data without altering its geometric structure. An analysis of EEG data from three patients experiencing epileptic seizures is made using the developed measure, resulting in successful identification of increased potential difference in portions of the brain that correspond to physical symptoms demonstrated by the patients. A mapping then is devised to transport the measure data onto the surface of a high-dimensional manifold, enabling the analysis of seizures using directional statistics and manifold theory. The subset of seizure signals on the manifold is shown to be a topological space, verifying Ahmad's approach to use topological modelling.

  17. Simultaneous EEG and EMG biofeedback for peak performance in musicians.

    Science.gov (United States)

    Markovska-Simoska, Silvana; Pop-Jordanova, Nada; Georgiev, Dejan

    2008-07-01

    The aim of this study was to determine the effects of alpha neurofeedback and EMG biofeedback protocols for improvement of musical performance in violinists. The sample consisted of 12 music students (10 violinists and 2 viola players) from the Faculty of Music, Skopje (3 males, mean age of 20 +/- 0 and 9 females, mean age = 20.89 +/- 2.98). Six of them had a low alpha peak frequency (APF) ( 10 Hz). The sample was randomized in two groups. The students from the experimental group participated in 20 sessions of biofeedback (alpha/EMG), combined with music practice, while the students from the control group did only music practice. Average absolute power, interhemispheric coherence in the alpha band, alpha peak frequency (APF), individual alpha band width (IABW), amount of alpha suppression (AAS) and surface forehead integrated EMG power (IEMG), as well as a score on musical performance and inventories measuring anxiety, were assessed. Alpha-EEG/EMG-biofeedback was associated with a significant increase in average alpha power, APF and IABW in all the participants and with decreases in IEMG only in high-APF musicians. The biofeedback training success was positively correlated with the alpha power, IcoH, APF, IABW and baseline level of APF and IABW. Alpha-EEG/EMG biofeedback is capable of increasing voluntary self-regulation and the quality of musical performance. The efficiency of biofeedback training depends on the baseline EEG alpha activity status, in particular the APF.

  18. Assessing effect of meditation on cognitive workload using EEG signals

    Science.gov (United States)

    Jadhav, Narendra; Manthalkar, Ramchandra; Joshi, Yashwant

    2017-06-01

    Recent research suggests that meditation affects the structure and function of the brain. Cognitive load can be handled in effective way by the meditators. EEG signals are used to quantify cognitive load. The research of investigating effect of meditation on cognitive workload using EEG signals in pre and post-meditation is an open problem. The subjects for this study are young healthy 11 engineering students from our institute. The focused attention meditation practice is used for this study. EEG signals are recorded at the beginning of meditation and after four weeks of regular meditation using EMOTIV device. The subjects practiced meditation daily 20 minutes for 4 weeks. The 7 level arithmetic additions of single digit (low level) to three digits with carry (high level) are presented as cognitive load. The cognitive load indices such as arousal index, performance enhancement, neural activity, load index, engagement, and alertness are evaluated in pre and post meditation. The cognitive indices are improved in post meditation data. Power Spectral Density (PSD) feature is compared between pre and post-meditation across all subjects. The result hints that the subjects were handling cognitive load without stress (ease of cognitive functioning increased for the same load) after 4 weeks of meditation.

  19. An Experiment of Ocular Artifacts Elimination from EEG Signals using ICA and PCA Methods

    Directory of Open Access Journals (Sweden)

    Arjon Turnip

    2014-12-01

    Full Text Available In the modern world of automation, biological signals, especially Electroencephalogram (EEG is gaining wide attention as a source of biometric information. Eye-blinks and movement of the eyeballs produce electrical signals (contaminate the EEG signals that are collectively known as ocular artifacts. These noise signals are required to be separated from the EEG signals to obtain the accurate results. This paper reports an experiment of ocular artifacts elimination from EEG signal using blind source separation algorithm based on independent component analysis and principal component analysis. EEG signals are recorded on three conditions, which are normal conditions, closed eyes, and blinked eyes. After processing, the dominant frequency of EEG signals in the range of 12-14 Hz either on normal, closed, and blinked eyes conditions is obtained. 

  20. EEG-based "serious" games and monitoring tools for pain management.

    Science.gov (United States)

    Sourina, Olga; Wang, Qiang; Nguyen, Minh Khoa

    2011-01-01

    EEG-based "serious games" for medical applications attracted recently more attention from the research community and industry as wireless EEG reading devices became easily available on the market. EEG-based technology has been applied in anesthesiology, psychology, etc. In this paper, we proposed and developed EEG-based "serious" games and doctor's monitoring tools that could be used for pain management. As EEG signal is considered to have a fractal nature, we proposed and develop a novel spatio-temporal fractal based algorithm for brain state quantification. The algorithm is implemented with blobby visualization tools for patient monitoring and in EEG-based "serious" games. Such games could be used by patient even at home convenience for pain management as an alternative to traditional drug treatment.

  1. Hypoglycemia-Associated EEG Changes in Prepubertal Children With Type 1 Diabetes

    DEFF Research Database (Denmark)

    Hansen, Grith Lærkholm; Foli-Andersen, Pia; Fredheim, Siri

    2016-01-01

    BACKGROUND: The purpose of this study was to explore the possible difference in the electroencephalogram (EEG) pattern between euglycemia and hypoglycemia in children with type 1 diabetes (T1D) during daytime and during sleep. The aim is to develop a hypoglycemia alarm based on continuous EEG...... measurement and real-time signal processing. METHOD: Eight T1D patients aged 6-12 years were included. A hyperinsulinemic hypoglycemic clamp was performed to induce hypoglycemia both during daytime and during sleep. Continuous EEG monitoring was performed. For each patient, quantitative EEG (qEEG) measures...... in specific bands comparing hypoglycemia to euglycemia both during daytime and during sleep. In daytime the EEG-based algorithm identified hypoglycemia in all children on average at a blood glucose (BG) level of 2.5 ± 0.5 mmol/l and 18.4 (ranging from 0 to 55) minutes prior to blood glucose nadir. During...

  2. Functional Brain Imaging by EEG: A Window to the Human Mind

    DEFF Research Database (Denmark)

    Stahlhut, Carsten

    This thesis presents electroencephalography (EEG) brain imaging by covering topics as empirical evaluation of source confusion, probabilistic inverse methods, and source analysis performed on infant EEG data. In terms of source confusion we inspect how current sources within the brain may...... be confused with each other as noise is present in the EEG recordings. Moreover, we examine how errors in the forward model affect the source confusion. The primary aim of this thesis is to provide sharper EEG brain images by improving current inverse methods. In this relation we focus the attention on two...... topics in EEG source reconstruction, namely, the forward progation model (describing the mapping from the current sources within the brain to the sensors at the scalp) and the temporal patterns present in the EEG. As forward models may suffer from a number of errors including the geometrical...

  3. EEG review comments on the geotechnical reports provided by DOE to EEG under the stipulated agreement through March 1, 1983

    International Nuclear Information System (INIS)

    1983-04-01

    The purpose of the Environmental Evaluation Group (EEG) is to conduct an independent technical evaluation of the potential radiation exposure to people from the proposed federal radioactive Waste Isolation Pilot Plant (WIPP) near Carlsbad, in order to protect the public health and safety and ensure that there is minimal environmental degradation. Analyses are conducted of available data concerning the proposed site, the design of the repository, its planned operation, and its long-term stability. These analyses include assessments of reports issued by the US Department of Energy (DOE) and its contractors, other federal agencies and organizations, as they relate to the potential health, safety and environmental impacts from WIPP. This publication is a compilation of EEG's written comments on each of the following reports: Deep Dissolution; Breccia Pipes; DMG Hydrology; Natural Resources; Plans for Site and Preliminary Design Validation; Plans for Simulated Waste; Brine Reservoir Report; Disturbed Zone Exploration; and Fracture Flow in the Rustler Aquifers

  4. Classes of multichannel EEG microstates in light and deep hypnotic conditions

    OpenAIRE

    Katayama, Hitoshi; Gianotti, Lorena R. R.; Isotani, Toshiaki; Faber, Pascal L.; Sasada, Kyohei; Kinoshita, Toshihiko; Lehmann, Dietrich

    2007-01-01

    The study assessed the brain electric mechanisms of light and deep hypnotic conditions in the framework of EEG temporal microstates. Multichannel EEG of healthy volunteers during initial resting, light hypnosis, deep hypnosis, and eventual recovery was analyzed into temporal EEG microstates of four classes. Microstates are defined by the spatial configuration of their potential distribution maps ([Symbol: see text]potential landscapes') on the head surface. Because different potential landsca...

  5. EEG microstate sequences in healthy humans at rest reveal scale-free dynamics

    OpenAIRE

    Van De Ville, Dimitri; Britz, Juliane; Michel, Christoph M.

    2010-01-01

    Recent findings identified electroencephalography (EEG) microstates as the electrophysiological correlates of fMRI resting-state networks. Microstates are defined as short periods (100 ms) during which the EEG scalp topography remains quasi-stable; that is, the global topography is fixed but strength might vary and polarity invert. Microstates represent the subsecond coherent activation within global functional brain networks. Surprisingly, these rapidly changing EEG microstates correlate sig...

  6. Chaos analysis of EEG during isoflurane-induced loss of righting in rats

    OpenAIRE

    MacIver, M. B.; Bland, Brian H.

    2014-01-01

    It has long been known that electroencephalogram (EEG) signals generate chaotic strange attractors and the shape of these attractors correlate with depth of anesthesia. We applied chaos analysis to frontal cortical and hippocampal micro-EEG signals from implanted microelectrodes (layer 4 and CA1, respectively). Rats were taken to and from loss of righting reflex (LORR) with isoflurane and behavioral measures were compared to attractor shape. Resting EEG signals at LORR differed markedly from ...

  7. Recording EEG in immature rats with a novel miniature telemetry system

    Science.gov (United States)

    Zayachkivsky, A.; Lehmkuhle, M. J.; Fisher, J. H.; Ekstrand, J. J.

    2013-01-01

    Serial EEG recordings from immature rat pups are extremely difficult to obtain but important for analyzing animal models of neonatal seizures and other pediatric neurological conditions as well as normal physiology. In this report, we describe the features and applications of a novel miniature telemetry system designed to record EEG in rat pups as young as postnatal day 6 (P6). First, we have recorded electrographic seizure activity in two animal models of neonatal seizures, hypoxia- and kainate-induced seizures at P7. Second, we describe a viable approach for long-term continuous EEG monitoring of naturally reared rat pups implanted with EEG at P6. Third, we have used serial EEG recordings to record age-dependent changes in the background EEG signal as the animals matured from P7 to P11. The important advantages of using miniature wireless EEG technology are: 1) minimally invasive surgical implantation; 2) a device form-factor that is compatible with housing of rat pups with the dam and littermates; 3) serial recordings of EEG activity; and 4) low power consumption of the unit, theoretically allowing continuous monitoring for up to 2 yr without surgical reimplantation. The miniature EEG telemetry system provides a technical advance that allows researchers to record continuous and serial EEG recordings in neonatal rodent models of human neurological disorders, study the progression of the disease, and then assess possible therapies using quantitative EEG as an outcome measure. This new technical approach should improve animal models of human conditions that rely on EEG monitoring for diagnosis and therapy. PMID:23114207

  8. Consumer-grade EEG devices: are they usable for control tasks?

    OpenAIRE

    Maskeliunas, Rytis; Damasevicius, Robertas; Martisius, Ignas; Vasiljevas, Mindaugas

    2016-01-01

    We present the evaluation of two well-known, low-cost consumer-grade EEG devices: the Emotiv EPOC and the Neurosky MindWave. Problems with using the consumer-grade EEG devices (BCI illiteracy, poor technical characteristics, and adverse EEG artefacts) are discussed. The experimental evaluation of the devices, performed with 10 subjects asked to perform concentration/relaxation and blinking recognition tasks, is given. The results of statistical analysis show that both devices exhibit high var...

  9. Acute EEG findings in HIV-infected Zambian adults with new-onset seizure

    Science.gov (United States)

    Elafros, Melissa A.; Sikazwe, Izukanji; Birbeck, Gretchen L.; Kalungwana, Lisa; Potchen, Michael J.; Bositis, Christopher M.; Koralnik, Igor J.; Theodore, William H.

    2015-01-01

    Objective: To describe acute EEG findings in HIV-infected adults with new-onset seizure, assess baseline clinical characteristics associated with EEG abnormalities, and evaluate the relationship between EEG abnormalities and recurrent seizure. Methods: Eighty-one HIV-infected adults with new-onset seizure had EEG recordings during their index admission. Baseline characteristics assessed included HIV stage, seizure semiology, serum and CSF studies, neuroimaging, cognitive function based on the Zambian Mini-Mental State Examination and International HIV Dementia Scale, and psychiatric symptoms using the Shona Symptom Questionnaire. We evaluated the relationship between baseline characteristics and EEG abnormalities. Patients were followed for seizure recurrence, and the association between acute EEG abnormalities and seizure recurrence was assessed. Death was a secondary outcome. Results: Fifty-five patients had abnormal EEGs (68%): 18 (22%) had interictal spikes (12) or a recorded seizure (6). Among baseline clinical characteristics, more advanced HIV disease (p = 0.039) and any imaging abnormality (p = 0.027) were associated with abnormal EEGs. Cortical (p = 0.008) and white matter (p = 0.004) abnormalities were associated with slow posterior dominant rhythm. Patients were followed for a median of 303 days (interquartile range 103–560). Twenty-four (30%) died and 23 (28%) had recurrent seizures. EEG abnormalities were not associated with recurrent seizure. There was a nonsignificant association between seizures recorded during EEG and death (67% vs 26%, p = 0.051). Conclusions: EEG abnormalities are common in this population, particularly in patients with imaging abnormalities and advanced HIV. Acute EEG abnormalities were not associated with recurrent seizure, but high mortality rates during follow-up limited this analysis. PMID:25740861

  10. EEG analysis of seizure patterns using visibility graphs for detection of generalized seizures.

    Science.gov (United States)

    Wang, Lei; Long, Xi; Arends, Johan B A M; Aarts, Ronald M

    2017-10-01

    The traditional EEG features in the time and frequency domain show limited seizure detection performance in the epileptic population with intellectual disability (ID). In addition, the influence of EEG seizure patterns on detection performance was less studied. A single-channel EEG signal can be mapped into visibility graphs (VGS), including basic visibility graph (VG), horizontal VG (HVG), and difference VG (DVG). These graphs were used to characterize different EEG seizure patterns. To demonstrate its effectiveness in identifying EEG seizure patterns and detecting generalized seizures, EEG recordings of 615h on one EEG channel from 29 epileptic patients with ID were analyzed. A novel feature set with discriminative power for seizure detection was obtained by using the VGS method. The degree distributions (DDs) of DVG can clearly distinguish EEG of each seizure pattern. The degree entropy and power-law degree power in DVG were proposed here for the first time, and they show significant difference between seizure and non-seizure EEG. The connecting structure measured by HVG can better distinguish seizure EEG from background than those by VG and DVG. A traditional EEG feature set based on frequency analysis was used here as a benchmark feature set. With a support vector machine (SVM) classifier, the seizure detection performance of the benchmark feature set (sensitivity of 24%, FD t /h of 1.8s) can be improved by combining our proposed VGS features extracted from one EEG channel (sensitivity of 38%, FD t /h of 1.4s). The proposed VGS-based features can help improve seizure detection for ID patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. A statistically robust EEG re-referencing procedure to mitigate reference effect

    OpenAIRE

    Lepage, Kyle Q.; Kramer, Mark A.; Chu, Catherine J.

    2014-01-01

    Background: The electroencephalogram (EEG) remains the primary tool for diagnosis of abnormal brain activity in clinical neurology and for in vivo recordings of human neurophysiology in neuroscience research. In EEG data acquisition, voltage is measured at positions on the scalp with respect to a reference electrode. When this reference electrode responds to electrical activity or artifact all electrodes are affected. Successful analysis of EEG data often involves re-referencing procedures th...

  12. Adolescence & Parental History of Alcoholism: Insights from the Sleep EEG

    Science.gov (United States)

    Van Reen, Eliza; Acebo, Christine; LeBourgeois, Monique; Seifer, Ronald; Fallone, Gahan; Carskadon, Mary A.

    2014-01-01

    Background Disrupted sleep is a common complaint of individuals with alcohol use disorder and in abstinent alcoholics. Furthermore, among recovering alcoholics, poor sleep predicts relapse to drinking. Whether disrupted sleep in these populations results from prolonged alcohol use or precedes the onset of drinking is not known. The aim of the present study was to examine the sleep EEG in alcohol naïve, parental history positive (PH+) and negative (PH−) boys and girls. Methods All-night sleep EEG recordings in two longitudinal cohorts (child and teen) followed at 1.5 – 3 year intervals were analyzed. The child and teen participants were 9/10 and 15/16 years old at the initial assessment, respectively. Parental history status was classified by DSM-IV criteria applied to structured interviews (CDIS-IV) resulting in 14 PH− and 10 PH+ children and 14 PH− and 10 PH+ teens. Sleep data were visually scored in 30-second epochs using standard criteria. Power spectra were calculated for EEG derivations C3/A2, C4/A1, O2/A1, O1/A2 for NREM and REM sleep. Results We found no difference between PH+ and PH− individuals in either cohort for any visually scored sleep stage variable. Spectral power declined in both cohorts across assessments for NREM and REM sleep in all derivations and across frequencies independent of parental history status. With regard to parental history, NREM sleep EEG power was lower for the delta band in PH+ teens at both assessments for the central derivations. Furthermore, power in the sigma band for the right occipital derivation in both NREM and REM sleep was lower in PH+ children only at the initial assessment. Conclusions We found no gross signs of sleep disruption as a function of parental history. Modest differences in spectral EEG power between PH+ and PH− children and teens indicate that a marker of parental alcohol history may detectable in teens at risk for problem drinking. PMID:22486223

  13. Sleep influences the intracerebral EEG pattern of focal cortical dysplasia.

    Science.gov (United States)

    Menezes Cordeiro, Inês; von Ellenrieder, Nicolas; Zazubovits, Natalja; Dubeau, François; Gotman, Jean; Frauscher, Birgit

    2015-07-01

    Focal cortical dysplasia (FCD) is able to generate an intrinsic pathological EEG activity characterized by a continuous or near-continuous spiking. Different patterns of discharge were described. We examined quantitatively the distribution of the intracerebral FCD patterns in relation to sleep in order to investigate whether this activity is independent of thalamocortical influences. We analyzed the first sleep cycle of 5 patients with a diagnosis of FCD type II who underwent combined scalp-intracranial electroencephalography (EEG), and showed an intracranial EEG pattern typical for FCD. Three patterns of FCD intracranial EEG activity were identified in all 5 patients, and visually marked for a maximum of 30min of each stage (wake, N1, N2, N3, REM): spike or polyspike exceeding 2Hz (pattern 1), spike or polyspike interrupted by flat periods below 2Hz (pattern 2) and discharges of >15Hz low-voltage rhythmic activity with regular morphology (pattern 3). After marking, the percentages of the three patterns across the different stages were calculated. The three patterns of FCD were present between 45% and 97% of the total time analyzed. Pattern 1 was the predominant pattern in wakefulness (73-100%), N1 (76-97%) and N2 (58-88.5%) in all patients, and in REM in 4 of 5 patients (91-100%). During N2 and N3, there was an increase in pattern 2 in all patients, becoming the predominant pattern in 3 of the 5 patients during N3 (63-89%). Pattern 3 was rare and only sporadically observed during N2 and N3. Wakefulness and REM sleep showed a similar pattern (pattern 1) with a slight amplitude reduction in REM sleep. Despite the presence of an almost continuous discharge, sleep is an important modulator of the pathological EEG patterns found in FCD type II. This might suggest that dysplastic tissue is influenced by the thalamo-cortical control mechanisms involved in the generation of sleep. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Review on solving the forward problem in EEG source analysis

    Directory of Open Access Journals (Sweden)

    Vergult Anneleen

    2007-11-01

    Full Text Available Abstract Background The aim of electroencephalogram (EEG source localization is to find the brain areas responsible for EEG waves of interest. It consists of solving forward and inverse problems. The forward problem is solved by starting from a given electrical source and calculating the potentials at the electrodes. These evaluations are necessary to solve the inverse problem which is defined as finding brain sources which are responsible for the measured potentials at the EEG electrodes. Methods While other reviews give an extensive summary of the both forward and inverse problem, this review article focuses on different aspects of solving the forward problem and it is intended for newcomers in this research field. Results It starts with focusing on the generators of the EEG: the post-synaptic potentials in the apical dendrites of pyramidal neurons. These cells generate an extracellular current which can be modeled by Poisson's differential equation, and Neumann and Dirichlet boundary conditions. The compartments in which these currents flow can be anisotropic (e.g. skull and white matter. In a three-shell spherical head model an analytical expression exists to solve the forward problem. During the last two decades researchers have tried to solve Poisson's equation in a realistically shaped head model obtained from 3D medical images, which requires numerical methods. The following methods are compared with each other: the boundary element method (BEM, the finite element method (FEM and the finite difference method (FDM. In the last two methods anisotropic conducting compartments can conveniently be introduced. Then the focus will be set on the use of reciprocity in EEG source localization. It is introduced to speed up the forward calculations which are here performed for each electrode position rather than for each dipole position. Solving Poisson's equation utilizing FEM and FDM corresponds to solving a large sparse linear system. Iterative

  15. Correntropy measures to detect daytime sleepiness from EEG signals

    International Nuclear Information System (INIS)

    Melia, Umberto; Vallverdú, Montserrat; Caminal, Pere; Guaita, Marc; Montserrat, Josep M; Vilaseca, Isabel; Salamero, Manel; Gaig, Carles; Santamaria, Joan

    2014-01-01

    Excessive daytime sleepiness (EDS) is one of the main symptoms of several sleep related disorders and has a great impact on patients’ lives. While many studies have been carried out in order to assess daytime sleepiness, automatic EDS detection still remains an open problem. In this work, a novel approach to this issue based on correntropy function analysis of EEG signals was proposed in order to detect patients suffering from EDS. Multichannel EEG signals were recorded during five Maintenance of Wakefulness Tests (MWT) and Multiple Sleep Latency Tests (MSLT) alternated throughout the day for patients suffering from sleep disordered breathing (SDB). A group of 20 patients with EDS was compared with a group of 20 patients without daytime sleepiness (WDS), by analyzing 60 s EEG windows in a waking state. Measures obtained from the cross-correntropy function (CCORR) and auto-correntropy function (ACORR) were calculated in the EEG frequency bands: δ, 0.1–4 Hz; θ, 4–8 Hz; α, 8–12 Hz; β, 12–30 Hz; total band TB, 0.1–45 Hz. These functions permitted the quantification of complex signal properties and the non-linear couplings between different areas of the scalp. Statistical differences between EDS and WDS groups were mainly found in the β band during MSLT events (p-value < 0.0001). The WDS group presented more complexity in the occipital zone than the EDS group, while a stronger nonlinear coupling between the occipital and frontal regions was detected in EDS patients than in the WDS group. At best, ACORR and CCORR measures yielded sensitivity and specificity above 80% and the area under ROC curve (AUC) was above 0.85 in classifying EDS and WDS patients. These performances represent an improvement with respect to classical EEG indices applied in the same database (sensitivity and specificity were never above 80% and AUC was under 0.75). (paper)

  16. Frontal EEG asymmetry in borderline personality disorder is associated with alexithymia.

    Science.gov (United States)

    Flasbeck, Vera; Popkirov, Stoyan; Brüne, Martin

    2017-01-01

    Frontal EEG asymmetry is a widely studied correlate of emotion processing and psychopathology. Recent research suggests that frontal EEG asymmetry during resting state is related to approach/withdrawal motivation and is also found in affective disorders such as major depressive disorder. Patients with borderline personality disorder (BPD) show aberrant behavior in relation to both approach and withdrawal motivation, which may arguably be associated with their difficulties in emotion processing. The occurrence and significance of frontal EEG asymmetry in BPD, however, has received little attention. Thirty-seven BPD patients and 39 controls underwent resting EEG and completed several psychometric questionnaires. While there were no between-group differences in frontal EEG asymmetry, in BPD frontal EEG asymmetry scores correlated significantly with alexithymia. That is, higher alexithymia scores were associated with relatively lower right-frontal activity. A subsequent analysis corroborated the significant interaction between frontal EEG asymmetry and alexithymia, which was moderated by group. Our findings reveal that lower right frontal EEG asymmetry is associated with alexithymia in patients with BPD. This finding is in accordance with neurophysiological models of alexithymia that implicate a right hemisphere impairment in emotion processing, and could suggest frontal EEG asymmetry as a potential biomarker of relevant psychopathology in these patients.

  17. EEG frequency-amplitude characteristics of the successful recognition of emotional speech.

    Science.gov (United States)

    Kislova, O O; Rusalova, M N

    2010-07-01

    EEG frequency-amplitude characteristics were studied in two groups of subjects, with high and low "emotional hearing" measures. Comparison of power over the whole EEG range between the two groups of subjects led to the conclusion that the EEG activation level was significantly higher in subjects with low "emotional hearing" measures than in those with high levels. This group also showed a higher level of activation in the posterior temporal areas of the cortex of the right hemisphere on recognition of emotions in speech. Thus, high initial levels of cortical activation and greater EEG reactivity on hearing emotional phrases are factors hindering the recognition of emotional expression in speech.

  18. Quantitative EEG in assessment of anaesthetic depth: comparative study of methodology

    DEFF Research Database (Denmark)

    Thomsen, C. E.; Prior, P. F.

    1996-01-01

    ) and (4) a depth of anaesthesia monitor based on EEG pattern recognition (ADAM). Dose-response curves are presented for stepwise increases in stable end-tidal concentrations of each agent. Results indicated considerable inter-patient variability and the limitations of single EEG measures, particularly......Methodology for assessment of depth of anaesthesia based on analysis of the electroencephalogram (EEG) is controversial. Techniques range from display of single measures, for example median value of the frequency spectrum, to dedicated pattern recognition systems based on measures of several EEG...

  19. Combining nonlinear dimensionality reduction with wavelet network to solve EEG inverse problem.

    Science.gov (United States)

    Wu, Qing; Shi, Lukui; Wu, Youxi; Xu, Guizhi; Li, Ying; Yan, Weili

    2006-01-01

    An integrated multi-method system to analyze the neuroelectric source parameters of electroencephalography (EEG) signal is presented. In order to handle the large-scale high dimension data efficiently and provide a real-time localizer in EEG inverse problem, an improved isometric mapping algorithm is used to find the low dimensional manifolds from high dimensional recorded EEG. Then, based on reduced dimension data, a single-scaling radial-basis wavelet network module is employed to determine the parameters of different type of EEG source models. In our simulation experiments, satisfactory results are obtained.

  20. Holistic approach for automated background EEG assessment in asphyxiated full-term infants

    Science.gov (United States)

    Matic, Vladimir; Cherian, Perumpillichira J.; Koolen, Ninah; Naulaers, Gunnar; Swarte, Renate M.; Govaert, Paul; Van Huffel, Sabine; De Vos, Maarten

    2014-12-01

    Objective. To develop an automated algorithm to quantify background EEG abnormalities in full-term neonates with hypoxic ischemic encephalopathy. Approach. The algorithm classifies 1 h of continuous neonatal EEG (cEEG) into a mild, moderate or severe background abnormality grade. These classes are well established in the literature and a clinical neurophysiologist labeled 272 1 h cEEG epochs selected from 34 neonates. The algorithm is based on adaptive EEG segmentation and mapping of the segments into the so-called segments’ feature space. Three features are suggested and further processing is obtained using a discretized three-dimensional distribution of the segments’ features represented as a 3-way data tensor. Further classification has been achieved using recently developed tensor decomposition/classification methods that reduce the size of the model and extract a significant and discriminative set of features. Main results. Effective parameterization of cEEG data has been achieved resulting in high classification accuracy (89%) to grade background EEG abnormalities. Significance. For the first time, the algorithm for the background EEG assessment has been validated on an extensive dataset which contained major artifacts and epileptic seizures. The demonstrated high robustness, while processing real-case EEGs, suggests that the algorithm can be used as an assistive tool to monitor the severity of hypoxic insults in newborns.

  1. Parametric and Nonparametric EEG Analysis for the Evaluation of EEG Activity in Young Children with Controlled Epilepsy

    Directory of Open Access Journals (Sweden)

    Vangelis Sakkalis

    2008-01-01

    Full Text Available There is an important evidence of differences in the EEG frequency spectrum of control subjects as compared to epileptic subjects. In particular, the study of children presents difficulties due to the early stages of brain development and the various forms of epilepsy indications. In this study, we consider children that developed epileptic crises in the past but without any other clinical, psychological, or visible neurophysiological findings. The aim of the paper is to develop reliable techniques for testing if such controlled epilepsy induces related spectral differences in the EEG. Spectral features extracted by using nonparametric, signal representation techniques (Fourier and wavelet transform and a parametric, signal modeling technique (ARMA are compared and their effect on the classification of the two groups is analyzed. The subjects performed two different tasks: a control (rest task and a relatively difficult math task. The results show that spectral features extracted by modeling the EEG signals recorded from individual channels by an ARMA model give a higher discrimination between the two subject groups for the control task, where classification scores of up to 100% were obtained with a linear discriminant classifier.

  2. A dry EEG-system for scientific research and brain-computer interfaces

    Directory of Open Access Journals (Sweden)

    Thorsten Oliver Zander

    2011-05-01

    Full Text Available Although it ranks among the oldest tools in neuroscientific research, electroencephalography (EEG still forms the method of choice in a wide variety of clinical and research applications. In the context of Brain-Computer Interfacing (BCI, EEG recently has become a tool to enhance Human-Machine Interaction (HMI. EEG could be employed in a wider range of environments, especially for the use of BCI systems in a clinical context or at the homes of patients. However, the application of EEG in these contexts is impeded by the cumbersome preparation of the electrodes with conductive gel that is necessary to lower the impedance between electrodes and scalp. Dry electrodes could provide a solution to this barrier and allow for EEG applications outside the laboratory. In addition, dry electrodes may reduce the time needed for neurological exams in clinical practice. This study evaluates a prototype of a three-channel dry electrode EEG system, comparing it to state-of-the-art conventional EEG electrodes. Two experimental paradigms were used: first, Event-Related Potentials (ERP were investigated with a variant of the oddball paradigm. Second, features of the frequency domain were compared by a paradigm inducing occipital alpha. Furthermore, both paradigms were used to evaluate BCI classification accuracies of both EEG systems. Amplitude and temporal structure of ERPs as well as features in the frequency domain did not differ significantly between the EEG systems. BCI classification accuracies were equally high in both systems when the frequency domain was considered. With respect to the oddball classification accuracy, there were slight differences between the wet and dry electrode systems. We conclude that the tested dry electrodes were capable to detect EEG signals with good quality and that these signals can be used for research or BCI applications. Easy to handle electrodes may help to foster the use of EEG among a wider range of potential users.

  3. Similar or disparate brain patterns? The intra-personal EEG variability of three women with multiple personality disorder.

    Science.gov (United States)

    Lapointe, A R; Crayton, J W; DeVito, R; Fichtner, C G; Konopka, L M

    2006-07-01

    Quantitative EEG was used to assess the intra-personal variability of brain electrical activity for 3 women diagnosed with Multiple Personality Disorder (MPD). Two separate control groups (within-subject and between-subject) were used to test the hypothesis that the intra-personal EEG variability between 2 alters would be less than the interpersonal EEG variability between 2 controls, and similar to the intra-personal EEG variability of a single personality. This hypothesis was partially supported. In general, the 2 EEG records of a MPD subject (alter 1 vs. alter 2) were more different from one another than the 2 EEG records of a single control, but less different from one another than the EEG records of 2 separate controls. Most of the EEG variability between alters involved beta activity in the frontal and temporal lobes.

  4. EEG Mind Controlled Smart Prosthetic Arm – A Comprehensive Study

    Directory of Open Access Journals (Sweden)

    Taha Beyrouthy

    2017-06-01

    Full Text Available Recently, the field of prosthetics has seen many accomplishments especially with the integration of technological advancements. In this paper, different arm types (robotic, surgical, bionic, prosthetic and static are analyzed in terms of resistance, usage, flexibility, cost and potential. Most of these techniques have some problems; they are extremely expensive, hard to install and maintain and may require surgery. Therefore, our work introduces the initial design of an EEG mind controlled smart prosthetic arm. The arm is controlled by the brain commands, obtained from an electroencephalography (EEG headset, and equipped with a network of smart sensors and actuators that give the patient intelligent feedback about the surrounding environment and the object in contact. This network provides the arm with normal hand functionality, smart reflexes and smooth movements. Various types of sensors are used including temperature, pressure, ultrasonic proximity sensors, accelerometers, potentiometers, strain gauges and gyroscopes. The arm is completely 3D printed built from various lightweight and high strength materials that can handle high impacts and fragile elements as well. Our project requires the use of nine servomotors installed at different places in the arm. Therefore, the static and dynamic modes of servomotors are analyzed. The total cost of the project is estimated to be relatively cheap compared to other previously built arms. Many scenarios are analyzed corresponding to the actions that the prosthetic arm can perform, and an algorithm is created to match these scenarios. Experimental results show that the proposed EEG Mind-controlled Arm is a promising alternative for current solutions that require invasive and expensive surgical procedures.

  5. Electroencephalograph (EEG) study on self-contemplating image formation

    Science.gov (United States)

    Meng, Qinglei; Hong, Elliot; Choa, Fow-Sen

    2016-05-01

    Electroencephalography (EEG) is one of the most widely used electrophysiological monitoring methods and plays a significant role in studies of human brain electrical activities. Default mode network (DMN), is a functional connection of brain regions that are activated while subjects are not in task positive state or not focused on the outside world. In this study, EEG was used for human brain signals recording while all subjects were asked to sit down quietly on a chair with eyes closed and thinking about some parts of their own body, such as left and right hands, left and right ears, lips, nose, and the images of faces that they were familiar with as well as doing some simple mathematical calculation. The time is marker when the image is formed in the subject's mind. By analyzing brain activity maps 300ms right before the time marked instant for each of the 4 wave bands, Delta, Theta, Alpha and Beta waves. We found that for most EEG datasets during this 300ms, Delta wave activity would mostly locate at the frontal lobe or the visual cortex, and the change and movement of activities are slow. Theta wave activity tended to rotate along the edge of cortex either clockwise or counterclockwise. Beta wave behaved like inquiry types of oscillations between any two regions spread over the cortex. Alpha wave activity looks like a mix of the Theta and Beta activities but more close to Theta activity. From the observation we feel that Beta and high Alpha are playing utility role for information inquiry. Theta and low Alpha are likely playing the role of binding and imagination formation in DMN operations.

  6. Oscillatory EEG correlates of arithmetic strategies: A training study

    Directory of Open Access Journals (Sweden)

    Roland H. Grabner

    2012-10-01

    Full Text Available There has been a long tradition of research on mathematics education showing that children and adults use different strategies to solve arithmetic problems. Neurophysiological studies have recently begun to investigate the brain correlates of these strategies. The existing body of data, however, reflect static end points of the learning process and do not provide information on how brain activity changes in response to training or intervention. In this study, we explicitly address this issue by training participants in using fact retrieval strategies. We also investigate whether brain activity related to arithmetic fact learning is domain-specific or whether this generalizes to other learning materials, such as the solution of figural-spatial problems. Twenty adult students were trained on sets of two-digit multiplication problems and figural-spatial problems. After the training, they were presented with the trained and untrained problems while their brain activity was recorded by means of electroencephalography (EEG . In both problem types, the training resulted in accuracies over 90 % and significant decreases in solution times. Analyses of the oscillatory EEG data also revealed training effects across both problem types. Specifically, we observed training-related activity increases in the theta band (3-6 Hz and decreases in the lower alpha band (8-10 Hz, especially over parieto-occipital and parietal brain regions. These results provide the first evidence that a short term fact retrieval training results in significant changes in oscillatory EEG activity. These findings further corroborate the role of the theta band in the retrieval of semantic information from memory and suggest that theta activity is not only sensitive to fact retrieval in mental arithmetic but also in other domains.

  7. Oscillatory EEG Correlates of Arithmetic Strategies: A Training Study

    Science.gov (United States)

    Grabner, Roland H.; De Smedt, Bert

    2012-01-01

    There has been a long tradition of research on mathematics education showing that children and adults use different strategies to solve arithmetic problems. Neurophysiological studies have recently begun to investigate the brain correlates of these strategies. The existing body of data, however, reflect static end points of the learning process and do not provide information on how brain activity changes in response to training or intervention. In this study, we explicitly address this issue by training participants in using fact retrieval strategies. We also investigate whether brain activity related to arithmetic fact learning is domain-specific or whether this generalizes to other learning materials, such as the solution of figural-spatial problems. Twenty adult students were trained on sets of two-digit multiplication problems and figural-spatial problems. After the training, they were presented with the trained and untrained problems while their brain activity was recorded by means of electroencephalography (EEG). In both problem types, the training resulted in accuracies over 90% and significant decreases in solution times. Analyses of the oscillatory EEG data also revealed training effects across both problem types. Specifically, we observed training-related activity increases in the theta band (3–6 Hz) and decreases in the lower alpha band (8–10 Hz), especially over parietooccipital and parietal brain regions. These results provide the first evidence that a short-term fact retrieval training results in significant changes in oscillatory EEG activity. These findings further corroborate the role of the theta band in the retrieval of semantic information from memory and suggest that theta activity is sensitive to fact retrieval not only in mental arithmetic but also in other domains. PMID:23162495

  8. Time frequency analysis of olfactory induced EEG-power change.

    Directory of Open Access Journals (Sweden)

    Valentin Alexander Schriever

    Full Text Available The objective of the present study was to investigate the usefulness of time-frequency analysis (TFA of olfactory-induced EEG change with a low-cost, portable olfactometer in the clinical investigation of smell function.A total of 78 volunteers participated. The study was composed of three parts where olfactory stimuli were presented using a custom-built olfactometer. Part I was designed to optimize the stimulus as well as the recording conditions. In part II EEG-power changes after olfactory/trigeminal stimulation were compared between healthy participants and patients with olfactory impairment. In Part III the test-retest reliability of the method was evaluated in healthy subjects.Part I indicated that the most effective paradigm for stimulus presentation was cued stimulus, with an interstimulus interval of 18-20s at a stimulus duration of 1000ms with each stimulus quality presented 60 times in blocks of 20 stimuli each. In Part II we found that central processing of olfactory stimuli analyzed by TFA differed significantly between healthy controls and patients even when controlling for age. It was possible to reliably distinguish patients with olfactory impairment from healthy individuals at a high degree of accuracy (healthy controls vs anosmic patients: sensitivity 75%; specificity 89%. In addition we could show a good test-retest reliability of TFA of chemosensory induced EEG-power changes in Part III.Central processing of olfactory stimuli analyzed by TFA reliably distinguishes patients with olfactory impairment from healthy individuals at a high degree of accuracy. Importantly this can be achieved with a simple olfactometer.

  9. The urban brain: analysing outdoor physical activity with mobile EEG.

    Science.gov (United States)

    Aspinall, Peter; Mavros, Panagiotis; Coyne, Richard; Roe, Jenny

    2015-02-01

    Researchers in environmental psychology, health studies and urban design are interested in the relationship between the environment, behaviour settings and emotions. In particular, happiness, or the presence of positive emotional mindsets, broadens an individual's thought-action repertoire with positive benefits to physical and intellectual activities, and to social and psychological resources. This occurs through play, exploration or similar activities. In addition, a body of restorative literature focuses on the potential benefits to emotional recovery from stress offered by green space and 'soft fascination'. However, access to the cortical correlates of emotional states of a person actively engaged within an environment has not been possible until recently. This study investigates the use of mobile electroencephalography (EEG) as a method to record and analyse the emotional experience of a group of walkers in three types of urban environment including a green space setting. Using Emotiv EPOC, a low-cost mobile EEG recorder, participants took part in a 25 min walk through three different areas of Edinburgh. The areas (of approximately equal length) were labelled zone 1 (urban shopping street), zone 2 (path through green space) and zone 3 (street in a busy commercial district). The equipment provided continuous recordings from five channels, labelled excitement (short-term), frustration, engagement, long-term excitement (or arousal) and meditation. A new form of high-dimensional correlated component logistic regression analysis showed evidence of lower frustration, engagement and arousal, and higher meditation when moving into the green space zone; and higher engagement when moving out of it. Systematic differences in EEG recordings were found between three urban areas in line with restoration theory. This has implications for promoting urban green space as a mood-enhancing environment for walking or for other forms of physical or reflective activity. Published

  10. Decoding the Locus of Covert Visuospatial Attention from EEG Signals.

    Directory of Open Access Journals (Sweden)

    Thomas Thiery

    Full Text Available Visuospatial attention can be deployed to different locations in space independently of ocular fixation, and studies have shown that event-related potential (ERP components can effectively index whether such covert visuospatial attention is deployed to the left or right visual field. However, it is not clear whether we may obtain a more precise spatial localization of the focus of attention based on the EEG signals during central fixation. In this study, we used a modified Posner cueing task with an endogenous cue to determine the degree to which information in the EEG signal can be used to track visual spatial attention in presentation sequences lasting 200 ms. We used a machine learning classification method to evaluate how well EEG signals discriminate between four different locations of the focus of attention. We then used a multi-class support vector machine (SVM and a leave-one-out cross-validation framework to evaluate the decoding accuracy (DA. We found that ERP-based features from occipital and parietal regions showed a statistically significant valid prediction of the location of the focus of visuospatial attention (DA = 57%, p < .001, chance-level 25%. The mean distance between the predicted and the true focus of attention was 0.62 letter positions, which represented a mean error of 0.55 degrees of visual angle. In addition, ERP responses also successfully predicted whether spatial attention was allocated or not to a given location with an accuracy of 79% (p < .001. These findings are discussed in terms of their implications for visuospatial attention decoding and future paths for research are proposed.

  11. Portable wireless neurofeedback system of EEG alpha rhythm enhances memory.

    Science.gov (United States)

    Wei, Ting-Ying; Chang, Da-Wei; Liu, You-De; Liu, Chen-Wei; Young, Chung-Ping; Liang, Sheng-Fu; Shaw, Fu-Zen

    2017-11-13

    Effect of neurofeedback training (NFT) on enhancement of cognitive function or amelioration of clinical symptoms is inconclusive. The trainability of brain rhythm using a neurofeedback system is uncertainty because various experimental designs are used in previous studies. The current study aimed to develop a portable wireless NFT system for alpha rhythm and to validate effect of the NFT system on memory with a sham-controlled group. The proposed system contained an EEG signal analysis device and a smartphone with wireless Bluetooth low-energy technology. Instantaneous 1-s EEG power and contiguous 5-min EEG power throughout the training were developed as feedback information. The training performance and its progression were kept to boost usability of our device. Participants were blinded and randomly assigned into either the control group receiving random 4-Hz power or Alpha group receiving 8-12-Hz power. Working memory and episodic memory were assessed by the backward digital span task and word-pair task, respectively. The portable neurofeedback system had advantages of a tiny size and long-term recording and demonstrated trainability of alpha rhythm in terms of significant increase of power and duration of 8-12 Hz. Moreover, accuracies of the backward digital span task and word-pair task showed significant enhancement in the Alpha group after training compared to the control group. Our tiny portable device demonstrated success trainability of alpha rhythm and enhanced two kinds of memories. The present study suggest that the portable neurofeedback system provides an alternative intervention for memory enhancement.

  12. Sparse Source EEG Imaging with the Variational Garrote

    DEFF Research Database (Denmark)

    Hansen, Sofie Therese; Stahlhut, Carsten; Hansen, Lars Kai

    2013-01-01

    EEG imaging, the estimation of the cortical source distribution from scalp electrode measurements, poses an extremely ill-posed inverse problem. Recent work by Delorme et al. (2012) supports the hypothesis that distributed source solutions are sparse. We show that direct search for sparse solutio...... as implemented by the Variational Garrote (Kappen, 2011) provides excellent estimates compared with other widely used schemes, is computationally attractive, and by its separation of ’where’ and ’what’ degrees of freedom paves the road for the introduction of genuine prior information....

  13. EEG recordings as a source for the detection of IRBD

    DEFF Research Database (Denmark)

    Bisgaard, Sissel; Duun-Christensen, Bolette; Kempfner, Lykke

    2015-01-01

    The purpose of this pilot study was to develop a supportive algorithm for the detection of idiopathic Rapid Eye-Movement (REM) sleep Behaviour Disorder (iRBD) from EEG recordings. iRBD is defined as REM sleep without atonia with no current sign of neurodegenerative disease, and is one...... of the earliest known biomarkers of Parkinson's Disease (PD). It is currently diagnosed by polysomnography (PSG), primarily based on EMG recordings during REM sleep. The algorithm was developed using data collected from 42 control subjects and 34 iRBD subjects. A feature was developed to represent high amplitude...

  14. Neural correlates of emotional responses to music: an EEG study.

    Science.gov (United States)

    Daly, Ian; Malik, Asad; Hwang, Faustina; Roesch, Etienne; Weaver, James; Kirke, Alexis; Williams, Duncan; Miranda, Eduardo; Nasuto, Slawomir J

    2014-06-24

    This paper presents an EEG study into the neural correlates of music-induced emotions. We presented participants with a large dataset containing musical pieces in different styles, and asked them to report on their induced emotional responses. We found neural correlates of music-induced emotion in a number of frequencies over the pre-frontal cortex. Additionally, we found a set of patterns of functional connectivity, defined by inter-channel coherence measures, to be significantly different between groups of music-induced emotional responses. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  15. Feasibility of Seizure Prediction from intracranial EEG Recordings

    DEFF Research Database (Denmark)

    Henriksen, Jonas; Kjær, Troels; Thomsen, Carsten E.

    2009-01-01

    in a rigorously, out-of-sample manner. The MPC-feature is based on the synchronization measure, explained through the analytic signal approach where the Hilbert transform is used to find the instantaneous phase of an arbitrary signal. By a relative comparison between two different iEEG channels the phase...... synchronization was calculated. The feature was employed on the FSPEEG database containing 21 patients with 4.1 seizures in average (Winterhalder M et al. Epilepsy Behav. 2003;4(3):318-325.) to assess its predictive performance. Results: A sensitivity of 55% and a specificity of 62% were obtained after a unified...... prediction. The field still needs further investigation though....

  16. Quantification of the benefit from integrating MEG and EEG data in minimum l2-norm estimation.

    Science.gov (United States)

    Molins, A; Stufflebeam, S M; Brown, E N; Hämäläinen, M S

    2008-09-01

    Source current estimation from electromagnetic (MEG and EEG) signals is an ill-posed problem that often produces blurry or inaccurately positioned estimates. The two modalities have distinct factors limiting the resolution, e.g., MEG cannot detect radially oriented sources, while EEG is sensitive to accuracy of the head model. This makes combined EEG+MEG estimation techniques desirable, but different acquisition noise statistics, complexity of the head models, and lack of pertinent metrics all complicate the assessment of the resulting improvements. We investigated analytically the effect of including EEG recordings in MEG studies versus the addition of new MEG channels when computing noise-normalized minimum l(2)-norm estimates. Three-compartment boundary-element forward models were constructed using structural MRI scans for four subjects. Singular value analysis of the resulting forward models predicted better performance of the EEG+MEG case in the form of higher matrix rank. MNE inverse operators for EEG, MEG and EEG+MEG were constructed using the sensor noise covariance estimated from data. Metrics derived from the resolution matrices predicted higher spatial resolution in EEG+MEG as compared to MEG due to decreased spread (lower spatial dispersion, higher resolution index) with no reduction in dipole localization error. The effect was apparent in all source locations, with increased magnitude for deep areas such as the cingulate cortex. We were also able to corroborate the results for the somatosensory cortex using median nerve responses.

  17. The value of multichannel MEG and EEG in the presurgical evaluation of 70 epilepsy patients.

    Science.gov (United States)

    Knake, S; Halgren, E; Shiraishi, H; Hara, K; Hamer, H M; Grant, P E; Carr, V A; Foxe, D; Camposano, S; Busa, E; Witzel, T; Hämäläinen, M S; Ahlfors, S P; Bromfield, E B; Black, P M; Bourgeois, B F; Cole, A J; Cosgrove, G R; Dworetzky, B A; Madsen, J R; Larsson, P G; Schomer, D L; Thiele, E A; Dale, A M; Rosen, B R; Stufflebeam, S M

    2006-04-01

    To evaluate the sensitivity of a simultaneous whole-head 306-channel magnetoencephalography (MEG)/70-electrode EEG recording to detect interictal epileptiform activity (IED) in a prospective, consecutive cohort of patients with medically refractory epilepsy that were considered candidates for epilepsy surgery. Seventy patients were prospectively evaluated by simultaneously recorded MEG/EEG. All patients were surgical candidates or were considered for invasive EEG monitoring and had undergone an extensive presurgical evaluation at a tertiary epilepsy center. MEG and EEG raw traces were analysed individually by two independent reviewers. MEG data could not be evaluated due to excessive magnetic artefacts in three patients (4%). In the remaining 67 patients, the overall sensitivity to detect IED was 72% (48/67 patients) for MEG and 61% for EEG (41/67 patients) analysing the raw data. In 13% (9/67 patients), MEG-only IED were recorded, whereas in 3% (2/67 patients) EEG-only IED were recorded. The combined sensitivity was 75% (50/67 patients). Three hundred and six-channel MEG has a similarly high sensitivity to record IED as EEG and appears to be complementary. In one-third of the EEG-negative patients, MEG can be expected to record IED, especially in the case of lateral neocortical epilepsy and/or cortical dysplasia.

  18. Quantitative electroencephalography (qEEG to discriminate primary degenerative dementia from major depressive disorder (depression

    Directory of Open Access Journals (Sweden)

    Deslandes Andréa

    2004-01-01

    Full Text Available Electroencephalography (EEG can be a valuable technique to assess electrophysiological changes related to dementia. In patients suspected of having dementia, the EEG is often quite informative. The sensitivity of the EEG to detect correlates of psychiatric disorders has been enhanced by means of quantitative methods of analysis (quantitative EEG. Quantitative features are extracted from, at least, 2 minutes of artifact-free, eyes closed, resting EEG, log-transformed to obtain Gaussianity, age-regressed, and Z-transformed relative to population norms (Neurometrics database. Using a subset of quantitative EEG (qEEG features, forward stepwise discriminant analyses are used to construct classifier functions. Along this vein, the main objective of this experiment is to distinguish profiles of qEEG, which differentiate depressive from demented patients (n = 125. The results showed that demented patients present deviations above the control group in variables associated to slow rhythms: Normed Monopolar Relative Power Theta for Cz and Normed Bipolar Relative Power Theta for Head. On the other hand, the deviation below the control group occurs with the variable associated to alpha rhythm: Normed Monopolar Relative Power Alpha for P3, in dementia. Using this method, the present investigation demonstrated high discriminant accuracy in separating Primary Degenerative Dementia from Major Depressive Disorder (Depression.

  19. Detection of hypoglycemia associated EEG changes during sleep in type 1 diabetes mellitus

    DEFF Research Database (Denmark)

    Snogdal, Lena Sønder; Folkestad, Lars; Elsborg, Rasmus

    2012-01-01

    Nocturnal hypoglycemia is a feared complication to insulin treated diabetes. Impaired awareness of hypoglycemia (IAH) increases the risk of severe hypoglycemia. EEG changes are demonstrated during daytime hypoglycemia. In this explorative study, we test the hypothesis that specific hypoglycemia......-associated EEG-changes occur during sleep and are detectable in time for the patient to take action....

  20. Differences in EEG Oscillations during Vasoactive Stress Reactions in Extroverts and Introverts

    Directory of Open Access Journals (Sweden)

    A M Kustubayeva

    2012-12-01

    Full Text Available Hyperventilation (HV and breath-holding (BH are informative psychophysiological tests resulting in rapidly changing cerebral blood flow. The aim of our research was to determine differential EEG spectra of introverts/extroverts with induced HV and BH. Introverts revealed more intensive EEG reaction during HV, which was specifically shown by increased theta and gamma activity in all cortical areas.