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1

EEG Alpha Power and Intelligence.  

ERIC Educational Resources Information Center

Tested whether alpha power in different sub-bands is selectively related to intelligence. For 74 Austrian subjects, the EEG was recorded during a resting session and 2 different intelligence tests were performed. Findings show a strong positive correlation between intelligence and alpha power. (SLD)

Doppelmayr, M.; Klimesch, W.; Stadler, W.; Pollhuber, D.; Heine, C.

2002-01-01

2

EEG alpha power and creative ideation?  

PubMed Central

Neuroscientific studies revealed first insights into neural mechanisms underlying creativity, but existing findings are highly variegated and often inconsistent. Despite the disappointing picture on the neuroscience of creativity drawn in recent reviews, there appears to be robust evidence that EEG alpha power is particularly sensitive to various creativity-related demands involved in creative ideation. Alpha power varies as a function of creativity-related task demands and the originality of ideas, is positively related to an individuals’ creativity level, and has been observed to increase as a result of creativity interventions. Alpha increases during creative ideation could reflect more internally oriented attention that is characterized by the absence of external bottom-up stimulation and, thus, a form of top-down activity. Moreover, they could indicate the involvement of specific memory processes such as the efficient (re-)combination of unrelated semantic information. We conclude that increased alpha power during creative ideation is among the most consistent findings in neuroscientific research on creativity and discuss possible future directions to better understand the manifold brain mechanisms involved in creativity. PMID:23246442

Fink, Andreas; Benedek, Mathias

2014-01-01

3

Differences in EEG Alpha Activity Related to Giftedness.  

ERIC Educational Resources Information Center

In three experiments, differences in EEG alpha activity between 30 gifted and 30 average individuals were studied. Results support the hypothesis that higher alpha power during information processing displayed by gifted individuals may derive from the nonuse of many brain areas not required for the problem at hand. (SLD)

Jausovec, Norbert

1996-01-01

4

EEG Alpha Rhythms and Susceptibility to Hypnosis  

Microsoft Academic Search

DESPITE a rich literature of anecdotal and clinical material on the relationship of hypnosis to physiological functions, especially to events in the central nervous system, the research findings are highly equivocal. Most relevant studies have been concerned with shifts in brain wave patterns, as measured by the electroencephalogram (EEG). The studies have attempted to identify the underlying processes which accompany

Perry London; JOSEPH T. HART; MORRIS P. LEIBOVITZ

1968-01-01

5

EEG Alpha Synchronization Is Related to Top-Down Processing in Convergent and Divergent Thinking  

ERIC Educational Resources Information Center

Synchronization of EEG alpha activity has been referred to as being indicative of cortical idling, but according to more recent evidence it has also been associated with active internal processing and creative thinking. The main objective of this study was to investigate to what extent EEG alpha synchronization is related to internal processing…

Benedek, Mathias; Bergner, Sabine; Konen, Tanja; Fink, Andreas; Neubauer, Aljoscha C.

2011-01-01

6

Intra-cortical propagation of EEG alpha oscillations.  

PubMed

The most salient feature of spontaneous human brain activity as recorded with electroencephalography (EEG) are rhythmic fluctuations around 10Hz. These alpha oscillations have been reported to propagate over the scalp with velocities in the range of 5-15m/s. Since these velocities are in the range of action potential velocities through cortico-cortical axons, it has been hypothesized that the observed scalp waves reflect cortico-cortically mediated propagation of cortical oscillations. The reported scalp velocities however, appear to be inconsistent with those estimated from local field potential recordings in dogs, which are <1m/s and agree with the propagation velocity of action potentials in intra-cortical axons. In this study, we resolve these diverging findings using a combination of EEG data-analysis and biophysical modeling. In particular, we demonstrate that the observed scalp velocities can be accounted for by slow traveling oscillations, which provides support for the claim that spatial propagation of alpha oscillations is mediated by intra-cortical axons. PMID:25168275

Hindriks, Rikkert; van Putten, Michel J A M; Deco, Gustavo

2014-12-01

7

Enhanced EEG alpha time-domain phase synchrony during Transcendental Meditation: Implications for cortical integration theory  

Microsoft Academic Search

Information transfer and integration in the brain that leads to high-level cognitive processes requires neuronal coordination. High phase synchronization (zero-lag) in fast frequencies is implicated in integrating sensory events. Alpha EEG activity, long regarded as a passive “idling” frequency, is now being implicated in this integrative function. As an example, in brain pathology decreased alpha phase synchrony is correlated with

Russell Hebert; Dietrich Lehmann; Gabriel Tan; Fred Travis; Alarik Arenander

2005-01-01

8

Detecting alpha spindle events in EEG time series using adaptive autoregressive models  

PubMed Central

Background Rhythmic oscillatory activity is widely observed during a variety of subject behaviors and is believed to play a central role in information processing and control. A classic example of rhythmic activity is alpha spindles, which consist of short (0.5-2 s) bursts of high frequency alpha activity. Recent research has shown that alpha spindles in the parietal/occipital area are statistically related to fatigue and drowsiness. These spindles constitute sharp changes in the underlying statistical properties of the signal. Our hypothesis is that change point detection models can be used to identify the onset and duration of spindles in EEG. In this work we develop an algorithm that accurately identifies sudden bursts of narrowband oscillatory activity in EEG using techniques derived from change point analysis. Our motivating example is detection of alpha spindles in the parietal/occipital areas of the brain. Our goal is to develop an algorithm that can be applied to any type of rhythmic oscillatory activity of interest for accurate online detection. Methods In this work we propose modeling the alpha band EEG time series using discounted autoregressive (DAR) modeling. The DAR model uses a discounting rate to weigh points measured further in the past less heavily than points more recently observed. This model is used together with predictive loss scoring to identify periods of EEG data that are statistically significant. Results Our algorithm accurately captures changes in the statistical properties of the alpha frequency band. These statistical changes are highly correlated with alpha spindle occurrences and form a reliable measure for detecting alpha spindles in EEG. We achieve approximately 95% accuracy in detecting alpha spindles, with timing precision to within approximately 150?ms, for two datasets from an experiment of prolonged simulated driving, as well as in simulated EEG. Sensitivity and specificity values are above 0.9, and in many cases are above 0.95, for our analysis. Conclusion Modeling the alpha band EEG using discounted AR models provides an efficient method for detecting oscillatory alpha activity in EEG. The method is based on statistical principles and can generally be applied to detect rhythmic activity in any frequency band or brain region. PMID:24047117

2013-01-01

9

Alpha and beta EEG power reflects L-dopa acute administration in parkinsonian patients  

PubMed Central

Aim: To evaluate the effect of an acute L-dopa administration on eye-closed resting state electroencephalographic (EEG) activity of cognitively preserved Parkinsonian patients. Methods: We examined 24 right-handed patients diagnosed as uncomplicated probable Parkinson’s disease (PD). Each patient underwent Unified Parkinson’s Disease Rating Scale (UPDRS)-part-III evaluation before and 60 min after an oral load of L-dopa-methyl-ester/carbidopa 250/25 mg. Resting condition eyes-closed EEG data were recorded both pre- and post L-dopa load. Absolute EEG power values were calculated at each scalp derivation for Delta, Theta, Alpha and Beta frequency bands. UPDRS scores (both global and subscale scores) and EEG data (power values of different frequency bands for each scalp derivation) were submitted to a statistical analysis to compare Pre and Post L-Dopa conditions. Finally, a correlation analysis was carried out between EEG spectral content and UPDRS scores. Results: Considering EEG power spectral analysis, no statistically significant differences arose on Delta and Theta bands after L-dopa intake. Conversely, Alpha and Beta rhythms significantly increased on centro-parietal scalp derivations, as a function of L-dopa administration. Correlation analysis indicated a significant negative correlation between Beta power increase on centro-parietal areas and UPDRS subscores (Rigidity of arms and Bradykinesia). A minor significant negative correlation was also found between Alpha band increase and resting tremor. Conclusions: Assuming that a significant change in EEG power spectrum after L-dopa intake may be related to dopaminergic mechanisms, our findings are consistent with the hypothesis that dopaminergic defective networks are implicated in cortical oscillatory abnormalities at rest in non-demented PD patients. PMID:25452725

Melgari, Jean-Marc; Curcio, Giuseppe; Mastrolilli, Francesca; Salomone, Gaetano; Trotta, Laura; Tombini, Mario; di Biase, Lazzaro; Scrascia, Federica; Fini, Rita; Fabrizio, Emma; Rossini, Paolo Maria; Vernieri, Fabrizio

2014-01-01

10

Biofeedback Auditory Alpha EEG Training and Its Effect upon Anxiety and Reading Achievement.  

ERIC Educational Resources Information Center

The major purpose of this exploratory study was to determine if electroencephalographic (EEG) auditory biofeedback training combined with Open Focus relaxation therapy would increase alpha-brain-wave production in highly anxious freshman university students who were also deficient in reading skills. The subjects for the study were 15 volunteer…

Lally, Marianne B.

11

Differences in EEG Alpha Activity between Gifted and Non-Identified Individuals: Insights into Problem Solving.  

ERIC Educational Resources Information Center

This study examined differences in electroencephalography (EEG) alpha activity between gifted and nongifted Slovenian student-teachers (N=17 each). Gifted students showed greater left hemisphere activation than nongifted subjects in relaxed states, but lower activation during problem solving. The same pattern was observed in overall hemispheric…

Jausovec, Norbert

1997-01-01

12

The time-course of EEG alpha power changes in creative ideation  

PubMed Central

Increases in EEG alpha power during creative ideation are among the most consistent findings in the neuroscientific study of creativity, but existing studies did not focus on time-related changes of EEG alpha activity patterns during the process of creative ideation so far. Since several cognitive processes are involved in the generation of creative ideas, different EEG correlates may result as a function of time. In this study we addressed this crucial point. Forty-five participants worked on the “Alternative Uses Task” while the EEG was recorded and changes in task-related power (relative to rest) in the upper-frequency band (10–12 Hz) for three isochronous time intervals of the idea generation period were determined. Alpha power changes during idea generation followed a characteristic time course: we found a general increase of alpha power at the beginning of idea generation that was followed by a decrease and finally by a re-increase of alpha prior to responding that was most pronounced at parietal and temporal sites of the right hemisphere. Additionally, the production of more original ideas was accompanied by increasing hemispheric asymmetry (more alpha in the right than left hemisphere) with increasing duration of the idea generation period. The observed time course of brain activity may reflect the progression of different but well-known stages in the idea generation process: that is the initial retrieval of common and old ideas followed by the actual generation of novel and more creative ideas by overcoming typical responses through processes of mental simulation and imagination. PMID:24860485

Schwab, Daniela; Benedek, Mathias; Papousek, Ilona; Weiss, Elisabeth M.; Fink, Andreas

2014-01-01

13

Prefrontal EEG alpha asymmetry changes while observing disaster happening to other people: Cardiac correlates and prediction of emotional impact.  

PubMed

Changes of EEG alpha asymmetry in terms of increased right versus left sided activity in prefrontal cortex are considered to index activation of the withdrawal/avoidance motivational system. The present study aimed to add evidence of the validity of individual differences in the EEG alpha asymmetry response and their relevance regarding the impact of emotional events. The magnitude of the EEG alpha asymmetry response while watching a film consisting of scenes of real injury and death correlated with components of transient cardiac responses to sudden horrifying events happening to persons in the film which index withdrawal/avoidance motivation and heightened attention and perceptual intake. Additionally, it predicted greater mood deterioration following the film and film-related intrusive memories and avoidance over the following week. The study provides further evidence for prefrontal EEG alpha asymmetry changes in response to relevant stimuli reflecting an individual's sensitivity to negative social-emotional cues encountered in everyday life. PMID:25224180

Papousek, Ilona; Weiss, Elisabeth M; Schulter, Günter; Fink, Andreas; Reiser, Eva M; Lackner, Helmut K

2014-12-01

14

A novel EEG for alpha brain state training, neurobiofeedback and behavior change.  

PubMed

Mindfulness meditation, with the resulting alpha brain state, is gaining a strong following as an adjunct to health, so too is applying self-affirmation to stimulate behavior change through subconscious re-programming. Until recently the EEG technology needed to demonstrate this has been cumbersome and required specialist training. This paper reports a pilot study using a remote EEG headband, which through a sophisticated algorithm, provides a real-time EEG readout unencumbered by conventional artifacts. In a convenience sample of 13, the difference in brain waves was examined while the subjects were occupied in an 'attention' and an 'alpha mind state' exercise. There was a significant difference in the mean scores for theta, delta, beta and gamma brain waves. Alpha brain waves remained static suggesting an ability of the headset to discriminate a mindful state and to provide real-time, easy to interpret feedback for the facilitator and subject. The findings provide encouragement for research applications in health care activities providing neurobiofeedback to subjects involved in mindfulness behavior change activities. PMID:23890456

Stinson, Bruce; Arthur, David

2013-08-01

15

The Effect of Alpha Rhythm Sleep on EEG Activity and Individuals’ Attention  

PubMed Central

[Purpose] This study examined whether the alpha rhythm sleep alters the EEG activity and response time in the attention and concentration tasks. [Subjects and Methods] The participants were 30 healthy university students, who were randomly and equally divided into two groups, the experimental and control groups. They were treated using the Happy-sleep device or a sham device, respectively. All participants had a one-week training period. Before and after training sessions, a behavioral task test was performed and EEG alpha waves were measured to confirm the effectiveness of training on cognitive function. [Results] In terms of the behavioral task test, reaction time (RT) variations in the experimental group were significantly larger than in the control group for the attention item. Changes in the EEG alpha power in the experimental group were also significantly larger than those of the control group. [Conclusions] These findings suggest that sleep induced using the Happy-sleep device modestly enhances the ability to pay attention and focus during academic learning. PMID:24409009

Kim, Seon Chill; Lee, Myoung Hee; Jang, Chel; Kwon, Jung Won; Park, Joo Wan

2014-01-01

16

EEG Alpha and Beta Activity in Normal and Deaf Subjects.  

ERIC Educational Resources Information Center

Electroencephalogram and task performance data were collected from three groups of young adult males: profoundly deaf Ss who signed from an early age, profoundly deaf Ss who only used oral (speech and speedreading) methods of communication, and normal hearing Ss. Alpha and Beta brain wave patterns over the Wernicke's area were compared across…

Waldron, Manjula; And Others

17

Dynamics of alpha control: Preparatory suppression of posterior alpha oscillations by frontal modulators revealed with combined EEG and event-related optical signal (EROS)  

PubMed Central

We investigated the dynamics of brain processes facilitating conscious experience of external stimuli. Previously we proposed that alpha (8-12 Hz) oscillations, which fluctuate with both sustained and directed attention, represent a pulsed inhibition of ongoing sensory brain activity. Here we tested the prediction that inhibitory alpha oscillations in visual cortex are modulated by top-down signals from frontoparietal attention networks. We measured modulations in phase-coherent alpha oscillations from superficial frontal, parietal, and occipital cortices using the event-related optical signal (EROS), a measure of neuronal activity affording high spatiotemporal resolution, along with concurrently-recorded electroencephalogram (EEG), while subjects performed a visual target-detection task. The pre-target alpha oscillations measured with EEG and EROS from posterior areas were larger for subsequently undetected targets, supporting alpha's inhibitory role. Using EROS, we localized brain correlates of these awareness-related alpha oscillations measured at the scalp to the cuneus and precuneus. Crucially, EROS alpha suppression correlated with posterior EEG alpha power across subjects. Sorting the EROS data based on EEG alpha power quartiles to investigate alpha modulators revealed that suppression of posterior alpha was preceded by increased activity in regions of the dorsal attention network, and decreased activity in regions of the cingulo-opercular network. Cross-correlations revealed the temporal dynamics of activity within these preparatory networks prior to posterior alpha modulation. The novel combination of EEG and EROS afforded localization of the sources and correlates of alpha oscillations and their temporal relationships, supporting our proposal that top-down control from attention networks modulates both posterior alpha and awareness of visual stimuli. PMID:24702458

Mathewson, Kyle E.; Beck, Diane M.; Ro, Tony; Maclin, Edward L.; Low, Kathy A.; Fabiani, Monica; Gratton, Gabriele

2015-01-01

18

Dynamics of alpha control: preparatory suppression of posterior alpha oscillations by frontal modulators revealed with combined EEG and event-related optical signal.  

PubMed

We investigated the dynamics of brain processes facilitating conscious experience of external stimuli. Previously, we proposed that alpha (8-12 Hz) oscillations, which fluctuate with both sustained and directed attention, represent a pulsed inhibition of ongoing sensory brain activity. Here we tested the prediction that inhibitory alpha oscillations in visual cortex are modulated by top-down signals from frontoparietal attention networks. We measured modulations in phase-coherent alpha oscillations from superficial frontal, parietal, and occipital cortices using the event-related optical signal (EROS), a measure of neuronal activity affording high spatiotemporal resolution, along with concurrently recorded EEG, while participants performed a visual target detection task. The pretarget alpha oscillations measured with EEG and EROS from posterior areas were larger for subsequently undetected targets, supporting alpha's inhibitory role. Using EROS, we localized brain correlates of these awareness-related alpha oscillations measured at the scalp to the cuneus and precuneus. Crucially, EROS alpha suppression correlated with posterior EEG alpha power across participants. Sorting the EROS data based on EEG alpha power quartiles to investigate alpha modulators revealed that suppression of posterior alpha was preceded by increased activity in regions of the dorsal attention network and decreased activity in regions of the cingulo-opercular network. Cross-correlations revealed the temporal dynamics of activity within these preparatory networks before posterior alpha modulation. The novel combination of EEG and EROS afforded localization of the sources and correlates of alpha oscillations and their temporal relationships, supporting our proposal that top-down control from attention networks modulates both posterior alpha and awareness of visual stimuli. PMID:24702458

Mathewson, Kyle E; Beck, Diane M; Ro, Tony; Maclin, Edward L; Low, Kathy A; Fabiani, Monica; Gratton, Gabriele

2014-10-01

19

Heart beats brain: The problem of detecting alpha waves by neuronal current imaging in joint EEG-MRI experiments.  

PubMed

It has been suggested recently that the influence of the neuro-magnetic field should make electrical brain activity directly detectable by MRI. To test this hypothesis, we performed combined EEG-MRI experiments which aim to localize the neuronal current sources of alpha waves (8-12 Hz), one of the most prominent EEG phenomena in humans. A detailed analysis of cross-spectral coherence between simultaneously recorded EEG and MRI time series revealed no sign of alpha waves. Instead the EEG-MRI approach was found to be hampered by artefacts due to cardiac pulsation, which extend into the frequency band of alpha waves. Separate brain displacement mapping experiments confirmed that not only the EEG but also the MRI signal is confounded by harmonics of the cardiac frequency even at 10 Hz and beyond. This well-known ballistocardiogram artefact cannot be avoided or eliminated entirely by available signal processing techniques. Therefore we must conclude that current EEG-MRI methodology based on correlation analysis lacks not only the sensitivity but also the specificity required for the reliable detection of alpha waves. PMID:17544703

Mandelkow, H; Halder, P; Brandeis, D; Soellinger, M; de Zanche, N; Luechinger, R; Boesiger, P

2007-08-01

20

EEG-based Upper-Alpha Neurofeedback for Cognitive Enhancement in Major Depressive Disorder: A preliminary, uncontrolled study  

E-print Network

EEG-based Upper-Alpha Neurofeedback for Cognitive Enhancement in Major Depressive Disorder cognitive deficits, such as depressive subjects, remains underexplored. This paper reports on a preliminary uncontrolled study to assess the effects of an upper-alpha NF intervention on patients with major depressive

Minguez, Javier

21

Relation of EEG alpha background to cognitive fuction, brain atrophy, and cerebral metabolism in Down's syndrome. Age-specific changes  

SciTech Connect

We studied 19 young adults (19 to 37 years old) and 9 older patients (42 to 66 years old) with Down's syndrome (DS) and a control group of 13 healthy adults (22 to 38 years old) to investigate the relation of electroencephalographic (EEG) alpha background to cognitive function and cerebral metabolism. Four of the older patients with DS had a history of mental deterioration, disorientation, and memory loss and were demented. Patients and control subjects had EEGs, psychometric testing, quantitative computed tomography, and positron emission tomography with fludeoxyglucose F 18. A blinded reader classified the EEGs into two groups--those with normal alpha background or those with abnormal background. All the control subjects, the 13 young adult patients with DS, and the 5 older patients with DS had normal EEG backgrounds. In comparison with the age-matched patients with DS with normal alpha background, older patients with DS with decreased alpha background had dementia, fewer visuospatial skills, decreased attention span, larger third ventricles, and a global decrease in cerebral glucose utilization with parietal hypometabolism. In the young patients with DS, the EEG background did not correlate with psychometric or positron emission tomographic findings, but the third ventricles were significantly larger in those with abnormal EEG background. The young patients with DS, with or without normal EEG background, had positron emission tomographic findings similar to those of the control subjects. The mechanism underlying the abnormal EEG background may be the neuropathologic changes of Alzheimer's disease in older patients with DS and may be cerebral immaturity in younger patients with DS.

Devinsky, O.; Sato, S.; Conwit, R.A.; Schapiro, M.B. (National Institute of Neurological Disorders and Stroke, Bethesda, MD (USA))

1990-01-01

22

EEG alpha power and alpha power asymmetry in sleep and wakefulness  

E-print Network

sleep, particularly during rapid eye movement ~REM! sleep. These results suggest that patterns during dreaming. During sleep, alpha power was highest during slow-wave sleep and lowest during REM sleep and sleeping are considered. Descriptors: Electroencephalography, Alpha, Sleep, REM sleep, Human Individual

Wisconsin at Madison, University of

23

Topographic distribution of EEG alpha attractor correlation dimension values in wake and drowsy states in humans.  

PubMed

Organization of resting state cortical networks is of fundamental importance for the phenomenon of awareness, which is altered in the first part of hypnagogic period (Hori stages 1-4). Our aim was to investigate the change in brain topography pattern of EEG alpha attractor correlation dimension (CD) in the period of transition from Hori stage 1 to 4. EEG of ten healthy adult individuals was recorded in the wake and drowsy states, using a 14 channel average reference montage, from which 91 bipolar channels were derived and filtered in the wider alpha (6-14Hz) range. Sixty 1s long epochs of each state and individual were subjected to CD calculation according to the Grassberger-Procaccia method. For such a collection of signals, two embedding dimensions, d={5, 10}, and 22 time delays ?=2-23 samples were explored. Optimal values were d=10 and ?=18, where both saturation and second zero crossing of the autocorrelation function occurred. Bipolar channel CD underwent a significant decrease during the transition and showed a positive linear correlation with electrode distance, stronger in the wake individuals. Topographic distribution of bipolar channels with above median CD changed from longitudinal anterior-posterior pattern (awake) to a more diagonal pattern, with localization in posterior regions (drowsiness). Our data are in line with the literature reporting functional segregation of neuronal assemblies in anterior and posterior regions during this transition. Our results should contribute to understanding of complex reorganization of the cortical part of alpha generators during the wake/drowsy transition. PMID:25462218

Kalauzi, Aleksandar; Vuckovic, Aleksandra; Boji?, Tijana

2014-11-22

24

Kinesthetic and vestibular information modulate alpha activity during spatial navigation: a mobile EEG study  

PubMed Central

In everyday life, spatial navigation involving locomotion provides congruent visual, vestibular, and kinesthetic information that need to be integrated. Yet, previous studies on human brain activity during navigation focus on stationary setups, neglecting vestibular and kinesthetic feedback. The aim of our work is to uncover the influence of those sensory modalities on cortical processing. We developed a fully immersive virtual reality setup combined with high-density mobile electroencephalography (EEG). Participants traversed one leg of a triangle, turned on the spot, continued along the second leg, and finally indicated the location of their starting position. Vestibular and kinesthetic information was provided either in combination, as isolated sources of information, or not at all within a 2 × 2 full factorial intra-subjects design. EEG data were processed by clustering independent components, and time-frequency spectrograms were calculated. In parietal, occipital, and temporal clusters, we detected alpha suppression during the turning movement, which is associated with a heightened demand of visuo-attentional processing and closely resembles results reported in previous stationary studies. This decrease is present in all conditions and therefore seems to generalize to more natural settings. Yet, in incongruent conditions, when different sensory modalities did not match, the decrease is significantly stronger. Additionally, in more anterior areas we found that providing only vestibular but no kinesthetic information results in alpha increase. These observations demonstrate that stationary experiments omit important aspects of sensory feedback. Therefore, it is important to develop more natural experimental settings in order to capture a more complete picture of neural correlates of spatial navigation. PMID:24616681

Ehinger, Benedikt V.; Fischer, Petra; Gert, Anna L.; Kaufhold, Lilli; Weber, Felix; Pipa, Gordon; König, Peter

2014-01-01

25

Effects of Drawing on Alpha Activity: A Quantitative EEG Study with Implications for Art Therapy  

ERIC Educational Resources Information Center

Little empirical evidence exists as to how materials used in art therapy affect the brain and its neurobiological functioning. This pre/post within-groups study utilized the quantitative electroencephalogram (qEEG) to measure residual effects in the brain after 20 minutes of drawing. EEG recordings were conducted before and after participants (N =…

Belkofer, Christopher M.; Van Hecke, Amy Vaughan; Konopka, Lukasz M.

2014-01-01

26

Human anterior and frontal midline theta and lower alpha reflect emotionally positive state and internalized attention: high-resolution EEG investigation of meditation  

Microsoft Academic Search

EEG spectral power and coherence estimates in the individually defined delta, theta, alpha-1, alpha-2, and alpha-3 bands were used to identify and characterize brain regions involved in meditative states, in which focused internalized attention gives rise to emotionally positive ‘blissful’ experience. Blissful state was accompanied by increased anterior frontal and midline theta synchronization as well as enhanced theta long-distant connectivity

L. I. Aftanas; S. A. Golocheikine

2001-01-01

27

Pink1 suppresses alpha-synuclein-induced phenotypes in a Drosophila model of Parkinson's disease.  

PubMed

Parkinson's disease (PD) is the most prevalent human neurodegenerative movement disorder and is characterized by a selective and progressive loss of the dopaminergic neurons. Mutations in the genes parkin and PTEN-induced putative kinase 1 (PINK1) result in autosomal recessive forms of PD. It has been suggested that parkin and Pink1 function in the same pathway in Drosophila, with Pink1 acting upstream of parkin. Previous work in our laboratory has shown the ability of parkin to rescue an alpha-synuclein-induced PD-like phenotype in Drosophila. To investigate the ability of Pink1 to protect against alpha-synuclein-induced toxicity, we have performed longevity, mobility, and histological studies to determine whether Drosophila Pink1 can rescue the alpha-synuclein phenotypes. We have found that overexpression of Pink1 results in the rescue of the alpha-synuclein-induced phenotype of premature loss of climbing ability, suppression of degeneration of the ommatidial array, and the suppression of alpha-synuclein-induced developmental defects in the Drosophila eye. These results mark the first demonstration of Pink1 counteracting PD phenotypes in a protein toxicity animal model, and they show that Pink1 is able to impart protection against potentially harmful proteins such as alpha-synuclein that would otherwise result in cellular stress. PMID:19088817

Todd, Amy M; Staveley, Brian E

2008-12-01

28

EEG alpha activity reflects motor preparation rather than the mode of action selection  

PubMed Central

Alpha-band activity (8–13 Hz) is not only suppressed by sensory stimulation and movements, but also modulated by attention, working memory and mental tasks, and could be sensitive to higher motor control functions. The aim of the present study was to examine alpha oscillatory activity during the preparation of simple left or right finger movements, contrasting the external and internal mode of action selection. Three preparation conditions were examined using a precueing paradigm with S1 as the preparatory and S2 as the imperative cue: Full, laterality instructed by S1; Free, laterality freely selected and None, laterality instructed by S2. Time-frequency (TF) analysis was performed in the alpha frequency range during the S1–S2 interval, and alpha motor-related amplitude asymmetries (MRAA) were also calculated. The significant MRAA during the Full and Free conditions indicated effective external and internal motor response preparation. In the absence of specific motor preparation (None), a posterior alpha event-related desynchronization (ERD) dominated, reflecting the main engagement of attentional resources. In Full and Free motor preparation, posterior alpha ERD was accompanied by a midparietal alpha event-related synchronization (ERS), suggesting a concomitant inhibition of task-irrelevant visual activity. In both Full and Free motor preparation, analysis of alpha power according to MRAA amplitude revealed two types of functional activation patterns: (1) a motor alpha pattern, with predominantly midparietal alpha ERS and large MRAA corresponding to lateralized motor activation/visual inhibition and (2) an attentional alpha pattern, with dominating right posterior alpha ERD and small MRAA reflecting visuospatial attention. The present results suggest that alpha oscillatory patterns do not resolve the selection mode of action, but rather distinguish separate functional strategies of motor preparation. PMID:22912607

Deiber, Marie-Pierre; Sallard, Etienne; Ludwig, Catherine; Ghezzi, Catherine; Barral, Jérôme; Ibañez, Vicente

2012-01-01

29

Tackling creativity at its roots: Evidence for different patterns of EEG alpha activity related to convergent and divergent modes of task processing  

PubMed Central

The distinction between convergent and divergent cognitive processes given by Guilford (1956) had a strong influence on the empirical research on creative thinking. Neuroscientific studies typically find higher event-related synchronization in the EEG alpha rhythm for individuals engaged in creative ideation tasks compared to intelligence-related tasks. This study examined, whether these neurophysiological effects can also be found when both cognitive processing modes (convergent vs. divergent) are assessed by means of the same task employing a simple variation of instruction. A sample of 55 participants performed the alternate uses task as well as a more basic word association task while EEG was recorded. On a trial-by-trial basis, participants were either instructed to find a most common solution (convergent condition) or a most uncommon solution (divergent condition). The answers given in the divergent condition were in both tasks significantly more original than those in the convergent condition. Moreover, divergent processing was found to involve higher task-related EEG alpha power than convergent processing in both the alternate uses task and the word association task. EEG alpha synchronization can hence explicitly be associated with divergent cognitive processing rather than with general task characteristics of creative ideation tasks. Further results point to a differential involvement of frontal and parietal cortical areas by individuals of lower versus higher trait creativity. PMID:22390860

Jauk, Emanuel; Benedek, Mathias; Neubauer, Aljoscha C.

2012-01-01

30

[A phase study of the glutamate-dependent EEG effects in the alpha- and beta-frequency ranges during the acute and subchronic administration of piracetam to rats].  

PubMed

The glutamatergic component of the piracetam effect upon the EEG frequency spectrum was studied in wakeful rats with electrodes implanted into somatosensory cortex and hippocampus and a cannula in the lateral ventricle. Piracetam at a dose of 400 mg/kg enhanced the EEG activity in the range of 10.4-16.4 Hz in two phases: early (10-40 min) and late (above 50 min). Only the late phase was retained against the background of the NMDA receptor antagonist CPP (0.1 nmole). This stage was also retained upon the subchronic administration of piracetam. The AMPA-receptor agonist quisqualate (5 nmole) enhanced the EEG power in the range of 1.5-5 Hz and decreased the activity at 10.4-16.4 Hz. The AMPA-receptor antagonist glutamate diethyl ester (1 mumole) leveled the agonist effect, but enhanced the piracetam action in the late phase at frequencies in the alpha range. PMID:10763101

Kovalev, G I; Vorob'ev, V V; Akhmetova, E R; Shibaev, N V

2000-01-01

31

Cortical EEG alpha rhythms reflect task-specific somatosensory and motor interactions in humans.  

PubMed

Anticipating sensorimotor events allows adaptive reactions to environment with crucial implications for self-protection and survival. Here we review several studies of our group that aimed to test the hypothesis that the cortical processes preparing the elaboration of sensorimotor interaction is reflected by the reduction of anticipatory electroencephalographic alpha power (about 8-12Hz; event-related desynchronization, ERD), as an index that regulate task-specific sensorimotor processes, accounted by high-alpha sub-band (10-12Hz), rather than a general tonic alertness, accounted by low-alpha sub-band (8-10Hz). In this line, we propose a model for human cortical processes anticipating warned sensorimotor interactions. Overall, we reported a stronger high-alpha ERD before painful than non-painful somatosensory stimuli that is also predictive of the subjective evaluation of pain intensity. Furthermore, we showed that anticipatory high-alpha ERD increased before sensorimotor interactions between non-painful or painful stimuli and motor demands involving opposite hands. In contrast, sensorimotor interactions between painful somatosensory and sensorimotor demands involving the same hand decreased anticipatory high-alpha ERD, due to a sort of sensorimotor "gating" effect. In conclusion, we suggest that anticipatory cortical high-alpha rhythms reflect the central interference and/or integration of ascending (sensory) and descending (motor) signals relative to one or two hands before non-painful and painful sensorimotor interactions. PMID:24929901

Babiloni, Claudio; Del Percio, Claudio; Arendt-Nielsen, Lars; Soricelli, Andrea; Romani, Gian Luca; Rossini, Paolo Maria; Capotosto, Paolo

2014-10-01

32

Pulsed Out of Awareness: EEG Alpha Oscillations Represent a Pulsed-Inhibition of Ongoing Cortical Processing  

PubMed Central

Alpha oscillations are ubiquitous in the brain, but their role in cortical processing remains a matter of debate. Recently, evidence has begun to accumulate in support of a role for alpha oscillations in attention selection and control. Here we first review evidence that 8–12 Hz oscillations in the brain have a general inhibitory role in cognitive processing, with an emphasis on their role in visual processing. Then, we summarize the evidence in support of our recent proposal that alpha represents a pulsed-inhibition of ongoing neural activity. The phase of the ongoing electroencephalography can influence evoked activity and subsequent processing, and we propose that alpha exerts its inhibitory role through alternating microstates of inhibition and excitation. Finally, we discuss evidence that this pulsed-inhibition can be entrained to rhythmic stimuli in the environment, such that preferential processing occurs for stimuli at predictable moments. The entrainment of preferential phase may provide a mechanism for temporal attention in the brain. This pulsed inhibitory account of alpha has important implications for many common cognitive phenomena, such as the attentional blink, and seems to indicate that our visual experience may at least some times be coming through in waves. PMID:21779257

Mathewson, Kyle E.; Lleras, Alejandro; Beck, Diane M.; Fabiani, Monica; Ro, Tony; Gratton, Gabriele

2011-01-01

33

Evidence for a dopaminergic link between working memory and agentic extraversion: an analysis of load-related changes in EEG alpha 1 activity.  

PubMed

Several lines of research point to the possibility of a partially overlapping dopaminergic foundation of the trait of agentic extraversion and individual differences in working memory functioning. This study investigates interactive effects of agentic extraversion and dopamine on spectral EEG measures of working memory. Using EEG activity in the alpha 1 band (8-10.25 Hz) as a dependent variable, we tested in a randomized double-blind design the effects of the D2-dopamine antagonist sulpiride during the performance of four load-graded n-back working memory tasks in participants high versus low in agentic extraversion. We expected extraversion-related differences in the load-responsivity pattern to be reversed by sulpiride, and the alpha 1 anterior-posterior difference actually depicted this reversal effect. However, in contrast to our expectations this effect was largely due to parietal instead of frontal sites. PMID:16904812

Chavanon, Mira-Lynn; Wacker, Jan; Leue, Anja; Stemmler, Gerhard

2007-01-01

34

EEG-Based Personalized Medicine in ADHD: Individual Alpha Peak Frequency as an Endophenotype Associated with Nonresponse  

Microsoft Academic Search

This review article summarizes some recent developments in psychiatry such as personalized medicine, employing biomarkers and endophenotypes, and developments collectively referred to as neuromodulation with a focus on ADHD. Several neurophysiological subtypes in ADHD and their relation to treatment outcome are reviewed. In older research the existence of an “abnormal EEG” or “paroxysmal EEG” was often reported, most likely explained

Martijn Arns

2012-01-01

35

Transcranial Alternating Current Stimulation Enhances Individual Alpha Activity in Human EEG  

PubMed Central

Non-invasive electrical stimulation of the human cortex by means of transcranial direct current stimulation (tDCS) has been instrumental in a number of important discoveries in the field of human cortical function and has become a well-established method for evaluating brain function in healthy human participants. Recently, transcranial alternating current stimulation (tACS) has been introduced to directly modulate the ongoing rhythmic brain activity by the application of oscillatory currents on the human scalp. Until now the efficiency of tACS in modulating rhythmic brain activity has been indicated only by inference from perceptual and behavioural consequences of electrical stimulation. No direct electrophysiological evidence of tACS has been reported. We delivered tACS over the occipital cortex of 10 healthy participants to entrain the neuronal oscillatory activity in their individual alpha frequency range and compared results with those from a separate group of participants receiving sham stimulation. The tACS but not the sham stimulation elevated the endogenous alpha power in parieto-central electrodes of the electroencephalogram. Additionally, in a network of spiking neurons, we simulated how tACS can be affected even after the end of stimulation. The results show that spike-timing-dependent plasticity (STDP) selectively modulates synapses depending on the resonance frequencies of the neural circuits that they belong to. Thus, tACS influences STDP which in turn results in aftereffects upon neural activity. The present findings are the first direct electrophysiological evidence of an interaction of tACS and ongoing oscillatory activity in the human cortex. The data demonstrate the ability of tACS to specifically modulate oscillatory brain activity and show its potential both at fostering knowledge on the functional significance of brain oscillations and for therapeutic application. PMID:21072168

Zaehle, Tino; Rach, Stefan; Herrmann, Christoph S.

2010-01-01

36

Alpha-tectorin involvement in hearing disabilities: one gene--two phenotypes.  

PubMed

The human alpha-tectorin (TECTA) gene has recently been cloned and proposed to be involved in autosomal dominant non-syndromic hearing impairment (NSHI) in two families linked to the DFNA12 locus. We have studied a Swedish pedigree with autosomal dominant NSHI with possible digenic inheritance of the disease, involving locus DFNA12 in chromosome 11 and locus DFNA2 in chromosome 1. Mutation analysis of the TECTA gene in this family has identified eight nucleotide substitutions indicating that TECTA is highly polymorphic. One of the changes results in a cysteine to serine (C 1057 S) mutation, in the zonadhesin domain of TECTA; this segregates with the disease haplotype on chromosome 11 and is not present in a control population. The mutation results in the replacement of a cysteine in one of the repeats of the zonadhesin/Von Willebrand domain of the protein and might cause a change in the crosslinking of the polypeptide. These findings add support to the involvement of TECTA in hearing disabilities. However, the three families carrying different TECTA mutations also show phenotypic differences: the hearing loss ranges from prelingual to progressive with late onset. The explanation for the different phenotypes and some clues regarding the functions of TECTA may lie in the localization of the mutations in the different modules of the protein. Another possibility is that the phenotype in the Swedish family is the result of two defective genes. PMID:10987647

Balciuniene, J; Dahl, N; Jalonen, P; Verhoeven, K; Van Camp, G; Borg, E; Pettersson, U; Jazin, E E

1999-09-01

37

“I am resting but rest less well with you.” The moderating effect of anxious attachment style on alpha power during EEG resting state in a social context  

PubMed Central

We took EEG recordings to measure task-free resting-state cortical brain activity in 35 participants under two conditions, alone (A) or together (T). We also investigated whether psychological attachment styles shape human cortical activity differently in these two settings. The results indicate that social context matters and that participants' cortical activity is moderated by the anxious, but not avoidant attachment style. We found enhanced alpha, beta and theta band activity in the T rather than the A resting-state condition, which was more pronounced in posterior brain regions. We further found a positive correlation between anxious attachment style and enhanced alpha power in the T vs. A condition over frontal and parietal scalp regions. There was no significant correlation between the absolute powers registered in the other two frequency bands and the participants' anxious attachment style. PMID:25071516

Verbeke, Willem J. M. I.; Pozharliev, Rumen; Van Strien, Jan W.; Belschak, Frank; Bagozzi, Richard P.

2014-01-01

38

Interacting memory systems-does EEG alpha activity respond to semantic long-term memory access in a working memory task?  

PubMed

Memory consists of various individual processes which form a dynamic system co-ordinated by central (executive) functions. The episodic buffer as direct interface between episodic long-term memory (LTM) and working memory (WM) is fairly well studied but such direct interaction is less clear in semantic LTM. Here, we designed a verbal delayed-match-to-sample task specifically to differentiate between pure information maintenance and mental manipulation of memory traces with and without involvement of access to semantic LTM. Task-related amplitude differences of electroencephalographic (EEG) oscillatory brain activity showed a linear increase in frontal-midline theta and linear suppression of parietal beta amplitudes relative to memory operation complexity. Amplitude suppression at upper alpha frequency, which was previously found to indicate access to semantic LTM, was only sensitive to mental manipulation in general, irrespective of LTM involvement. This suggests that suppression of upper EEG alpha activity might rather reflect unspecific distributed cortical activation during complex mental processes than accessing semantic LTM. PMID:25545793

Berger, Barbara; Omer, Serif; Minarik, Tamas; Sterr, Annette; Sauseng, Paul

2014-01-01

39

X linked mental retardation with non-deletional alpha thalassaemia (ATR-X): further delineation of the phenotype.  

PubMed Central

Two sibs with non-deletional alpha thalassaemia and mental retardation (ATR-X) have been ascertained showing variable neurological features. The proband had a complex neurological picture with recurrent apnoea, complex partial seizures, and prolonged periods of semiconsciousness between 12 and 17 months of age. Episodes of spontaneous laughter were also a feature. An EEG was initially normal. Hb H inclusions were present but rare in this family. The sole genital anomaly was deficiency of the foreskin, a feature not previously described in ATR-X. Images PMID:8014976

Ogle, R; DeSouza, M; Cunningham, C; Kerr, B; Sillence, D

1994-01-01

40

In vitro reprogramming of pancreatic alpha cells towards a beta cell phenotype following ectopic HNF4? expression.  

PubMed

There is currently a shortage of organ donors available for pancreatic beta cell transplantation into diabetic patients. An alternative source of beta cells is pre-existing pancreatic cells. While we know that beta cells can arise directly from alpha cells during pancreatic regeneration we do not understand the molecular basis for the switch in phenotype. The aim of the present study was to investigate if hepatocyte nuclear factor 4 alpha (HNF4?), a transcription factor essential for a normal beta cell phenotype, could induce the reprogramming of alpha cells towards potential beta cells. We utilised an in vitro model of pancreatic alpha cells, the murine ?TC1-9 cell line. We initially characterised the ?TC1-9 cell line before and following adenovirus-mediated ectopic expression of HNF4?. We analysed the phenotype at transcript and protein level and assessed its glucose-responsiveness. Ectopic HNF4? expression in the ?TC1-9 cell line induced a change in morphology (1.7-fold increase in size), suppressed glucagon expression, induced key beta cell-specific markers (insulin, C-peptide, glucokinase, GLUT2 and Pax4) and pancreatic polypeptide (PP) and enabled the cells to secrete insulin in a glucose-regulated manner. In conclusion, HNF4? reprograms alpha cells to beta-like cells. PMID:25224487

Sangan, Caroline B; Jover, Ramiro; Heimberg, Harry; Tosh, David

2015-01-01

41

Detection of nonlinear interactions of EEG alpha waves in the brain by a new coherence measure and its application to epilepsy and anti-epileptic drug therapy.  

PubMed

EEG and field potential rhythms established in the cortex and thalamus may accommodate the propagation of seizures. This article describes the interaction between thalamus and cortex during pentylenetetrazol (PTZ) seizures in rats with and without prior treatment with ethosuximide (ESM), a well-known antiepileptic drug (AED) that raises the threshold for seizures, was given before PTZ. The AED was given before PTZ convulsant administration. We track this thalamo-cortical association with a novel measure we have called the cross-bicoherence gain, or BISCOH. This quantity allows us to measure the spectral coherence in a purely higher order spectralmethodology. BISCOH is able to track the formation of nonlinearities at specific frequencies in the recorded EEG. BISCOH showed a strong increase in low alpha wave harmonic generationat 10 and 12.5 Hz after ESM treatment (p < 0.02 and p < 0.007, respectively). Conventional coherence failed to show distinctive and significant changes in thalamo-cortical coupling after ESM treatment at those frequencies and instead showed changes at 5 Hz. This rise in cortical rhythms is evidence of harmonic generation or new frequency formation in the thalamo-cortical system withAED therapy. BISCOH could become a powerful tool in unraveling changes in coherence due to neuroelectric modulation resulting from drug treatment or electrical stimulation. PMID:21442775

Sherman, David; Zhang, Ning; Garg, Shikha; Thakor, Nitish V; Mirski, Marek A; White, Mirinda Anderson; Hinich, Melvin J

2011-04-01

42

DETECTION OF NONLINEAR INTERACTIONS OF EEG ALPHA WAVES IN THE BRAIN BY A NEW COHERENCE MEASURE AND ITS APPLICATION TO EPILEPSY AND ANTI-EPILEPTIC DRUG THERAPY  

PubMed Central

EEG and field potential rhythms established in the cortex and thalamus may accommodate the propagation of seizures. This article describes the interaction between thalamus and cortex during pentylenetetrazol (PTZ) seizures in rats with and without prior treatment with ethosuximide (ESM), a well-known antiepileptic drug (AED) that raises the threshold for seizures, was given before PTZ. The AED was given before PTZ convulsant administration. We track this thalamo-cortical association with a novel measure we have called the cross-bicoherence gain, or BISCOH. This quantity allows us to measure the spectral coherence in a purely higher order spectralmethodology. BISCOH is able to track the formation of nonlinearities at specific frequencies in the recorded EEG. BISCOH showed a strong increase in low alpha wave harmonic generationat 10 and 12.5 Hz after ESM treatment (p < 0.02 and p < 0.007, respectively). Conventional coherence failed to show distinctive and significant changes in thalamo-cortical coupling after ESM treatment at those frequencies and instead showed changes at 5 Hz. This rise in cortical rhythms is evidence of harmonic generation or new frequency formation in the thalamo-cortical system with AED therapy. BISCOH could become a powerful tool in unraveling changes in coherence due to neuroelectric modulation resulting from drug treatment or electrical stimulation. PMID:21442775

SHERMAN, DAVID; ZHANG, NING; GARG, SHIKHA; THAKOR, NITISH V.; MIRSKI, MAREK A.; WHITE, MIRINDA ANDERSON; HINICH, MELVIN J.

2011-01-01

43

Splicing mutation in the ATR-X gene can lead to a dysmorphic mental retardation phenotype without {alpha}-thalassemia  

SciTech Connect

We have previously reported the isolation of a gene from Xq13 that codes for a putative regulator of transcription (XNP) and has now been shown to be the gene involved in the X-linked {alpha}-thalassemia with mental retardation (ATR-X) syndrome. The widespread expression and numerous domains present in the putative protein suggest that this gene could be involved in other phenotypes. The predominant expression of the gene in the developing brain, as well as its association with neuron differentiation, indicates that mutations of this gene might result in a mental retardation (MR) phenotype. In this paper we present a family with a splice junction mutation in XNP that results in the skipping of an exon and in the introduction of a stop codon in the middle of the XNP-coding sequence. Only the abnormal transcript is expressed in two first cousins presenting the classic ATR-X phenotype (with {alpha}-thalassemia and HbH inclusions). In a distant cousin presenting a similar dysmorphic MR phenotype but not having thalassemia, {approximately}30% of the XNP transcripts are normal. These data demonstrate that the mode of action of the XNP gene product on globin expression is distinct from its mode of action in brain development and facial morphogenesis and suggest that other dysmorphic mental retardation phenotypes, such as Juberg-Marsidi or some sporadic cases of Coffin-Lowry, could be due to mutations in XNP. 20 refs., 5 figs., 2 tabs.

Villard, L.; Lossi, A.M.; Fontes, M. [and others

1996-03-01

44

Splicing mutation in the ATR-X gene can lead to a dysmorphic mental retardation phenotype without alpha-thalassemia.  

PubMed Central

We have previously reported the isolation of a gene from Xq13 that codes for a putative regulator of transcription (XNP) and has now been shown to be the gene involved in the X-linked alpha-thalassemia with mental retardation (ATR-X) syndrome. The widespread expression and numerous domains present in the putative protein suggest that this gene could be involved in other phenotypes. The predominant expression of the gene in the developing brain, as well as its association with neuron differentiation, indicates that mutations of this gene might result in a mental retardation (MR) phenotype. In this paper we present a family with a splice junction mutation in XNP that results in the skipping of an exon and in the introduction of a stop codon in the middle of the XNP-coding sequence. Only the abnormal transcript is expressed in two first cousins presenting the classic ATR-X phenotype (with alpha-thalassemia and HbH inclusions). In a distant cousin presenting a similar dysmorphic MR phenotype but not having thalassemia, approximately 30% of the XNP transcripts are normal. These data demonstrate that the mode of action of the XNP gene product on globin expression is distinct from its mode of action in brain development and facial morphogenesis and suggest that other dysmorphic mental retardation phenotypes, such as Juberg-Marsidi or some sporadic cases of Coffin-Lowry, could be due to mutations in XNP. Images Figure 2 PMID:8644709

Villard, L.; Toutain, A.; Lossi, A. M.; Gecz, J.; Houdayer, C.; Moraine, C.; Fontès, M.

1996-01-01

45

Alpha1-antitrypsin Phenotypes and Neutrophil Elastase Gene Promoter Polymorphisms in Lung Cancer  

Microsoft Academic Search

Imbalance between neutrophil elastase and alpha-1-antitrypsin (AAT) leads to emphysema in smokers as well as in patients with\\u000a inherited alpha-1-antitrypsin deficiency. AAT as a proven inhibitor of apoptosis may play role in lung cancer (LC) progression.\\u000a The aim was to analyse AAT protein variants and polymorphism in promoter region of the neutrophil elastase gene (ELA2) in\\u000a patients with primary lung

Aleksandra Topic; Mila Ljujic; Aleksandra Nikolic; Natasa Petrovic-Stanojevic; Vesna Dopudja-Pantic; Marija Mitic-Milikic; Dragica Radojkovic

2011-01-01

46

Alpha 2 HS glycoprotein phenotypes and quantitative hormone and bone measures in postmenopausal women  

Microsoft Academic Search

Summary  It has been suggested that inherited traits play a role in the development of osteoporosis by providing a background for the\\u000a modulation of gene expression. In this study, we examine the influence of the different alleles of alpha2-HS glycoprotein (AHSG), a protein of the bone matrix, on quantitative estrogens, estrone and estradiol, and bone measures,\\u000a bone area and density. Estrogens

June E. Eichner; Christopher A. Friedrich; Jane A. Cauley; Mohammad I. Kamboh; James P. Gutai; Lewis H. Kuller; Robert E. Ferrell

1990-01-01

47

A short-term treatment with tumor necrosis factor-alpha enhances stem cell phenotype of human dental pulp cells  

PubMed Central

Introduction During normal pulp tissue healing, inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-?) or interleukins, act in the initial 48 hours (inflammatory phase) and play important roles not only as chemo-attractants of inflammatory cells and stem/progenitor cells but also in inducing a cascade of reactions toward tissue regeneration or reparative dentin formation or both. Previous reports have shown that inflammatory cytokines regulate the differentiation capacity of dental pulp stem/progenitor cells (DPCs), but none has interrogated the impact of these cytokines on the stem cell phenotype of stem/progenitor cells. This study investigated the effects of a short-term treatment with TNF-? on the stem cell phenotype and differentiation ability of human DPCs. Methods An in vivo mouse model of pulp exposure was performed for analysis of expression of the mesenchymal stem cell marker CD146 in DPCs during the initial stage of inflammatory response. For in vitro studies, human DPCs were isolated and incubated with TNF-? for 2 days and passaged to eliminate TNF-? completely. Analysis of stem cell phenotype was performed by quantification of cells positive for mesenchymal stem cell markers SSEA-4 (stage-specific embryonic antigen 4) and CD146 by flow cytometry as well as by quantitative analysis of telomerase activity and mRNA levels of OCT-4 and NANOG. Cell migration, colony-forming ability, and differentiation toward odontogenesis and adipogenesis were also investigated. Results The pulp exposure model revealed a strong staining for CD146 during the initial inflammatory response, at 2 days after pulp exposure. In vitro experiments demonstrated that a short-term (2-day) treatment of TNF-? increased by twofold the percentage of SSEA-4+ cells. Accordingly, STRO-1, CD146, and SSEA-4 protein levels as well as OCT-4 and NANOG mRNA levels were also significantly upregulated upon TNF-? treatment. A short-term TNF-? treatment also enhanced DPC function, including the ability to form cell colonies, to migrate, and to differentiate into odontogenic and adipogenic lineages. Conclusions A short-term treatment with TNF-? enhanced the stem cell phenotype, migration, and differentiation ability of DPCs. PMID:24580841

2014-01-01

48

Test-retest reliability of cognitive EEG  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

49

TNF-alpha impairs regulation of muscle oxidative phenotype: implications for cachexia?  

PubMed

Chronic obstructive pulmonary disease (COPD) is characterized by weight loss, muscle wasting (in advanced disease ultimately resulting in cachexia), and loss of muscle oxidative phenotype (oxphen). This study investigates the effect of inflammation (as a determinant of muscle wasting) on muscle oxphen by using cell studies combined with analyses of muscle biopsies of patients with COPD and control participants. We analyzed markers (citrate synthase, ?-hydroxyacyl-CoA dehydrogenase, and cytochrome c oxidase IV) and regulators (PGC-1?, PPAR-?, and Tfam) of oxphen in vastus lateralis muscle biopsies of patients with advanced COPD and healthy smoking control participants. Here 17 of 73 patients exhibited elevated muscle TNF-? mRNA levels. In these patients, significantly lower mRNA levels of all oxidative markers/regulators were found. Interestingly, these patients also had a significantly lower body mass index and tended to have less muscle mass. In cultured muscle cells, mitochondrial protein content and myosin heavy chain isoform I (but not II) protein and mRNA levels were reduced on chronic TNF-? stimulation. TNF-? also reduced mitochondrial respiration in a nuclear factor kappaB (NF-?B) -dependent manner. Importantly, TNF-?-induced NF-?B activation decreased promoter transactivation and transcriptional activity of regulators of mitochondrial biogenesis and muscle oxphen. In conclusion, these results demonstrate that TNF-? impairs muscle oxphen in a NF-?B-dependent manner. PMID:20807714

Remels, A H V; Gosker, H R; Schrauwen, P; Hommelberg, P P H; Sliwinski, P; Polkey, M; Galdiz, J; Wouters, E F M; Langen, R C J; Schols, A M W J

2010-12-01

50

Investigation of the modulation between EEG alpha waves and slow/fast delta waves in children in different depths of Desflurane anesthesia  

E-print Network

in different depths of Desflurane anesthesia Behnam Molaee-Ardekani1,2,3, , Mohammad-Bagher Shamsollahi3-band EEG activities in various depths of anesthesia (DOA). Methods: This modulation, which is a sort anesthesia. Two parameters are defined to quantify the modulation: strength of modulation (SOM) and phase

Paris-Sud XI, Université de

51

Full-length membrane bound TNF alpha acts through TNF receptor 2 to modify the phenotype of sensory neurons  

PubMed Central

Neuropathic pain resulting from spinal hemisection or selective spinal nerve ligation is characterized by an increase in membrane-bound TNF alpha (mTNF?) in spinal microglia without detectable release of soluble TNF alpha (sTNF?). In tissue culture, we showed that full length transmembrane cleavage-resistant TNF? (crTNF?) construct can act through cell-cell contact to activate neighboring microglia. We undertook the current study to test the hypothesis that mTNF? expressed in microglia might also affect the phenotype of primary sensory afferents, by determining the effect of crTNF? expressed from COS-7 cells on gene expression in primary DRG neurons. Co-culture of DRG neurons with crTNF?-expressing COS-7 cells resulted in a significant increase in the expression of voltage gated sodium channel isoforms NaV1.7 and NaV1.8, and voltage gated calcium channel subunit CaV3.2 at both mRNA and protein levels, and enhanced CCL2 expression and release from the DRG neurons. Exposure to sTNF? only produced an increase in CCL2 expression and release. Treatment of the cells with an siRNA against TNFR2 significantly reduced crTNF?-induced gene expression changes in DRG neurons while administration of CCR2 inhibitor had no significant effect on crTNF?-induced increase in gene expression and CCL2 release in DRG neurons. Taken together, the results suggest that mTNF? expressed in spinal microglia can facilitate pain signaling by up-regulating expression of cation channels and CCL2 in DRG neurons in a TNFR2 dependent manner. PMID:23711481

Wu, Zetang; Wang, Shiyong; Gruber, Sandy; Mata, Marina; Fink, David J.

2013-01-01

52

Preserved functional autonomic phenotype in adult mice overexpressing moderate levels of human alpha?synuclein in oligodendrocytes  

PubMed Central

Abstract Mice overexpressing human alpha?synuclein in oligodendrocytes (MBP1???syn) recapitulate some key functional and neuropathological features of multiple system atrophy (MSA). Whether or not these mice develop severe autonomic failure, which is a key feature of human MSA, remains unknown. We explored cardiovascular autonomic regulation using long?term blood pressure (BP) radiotelemetry and pharmacological testing. We instrumented 12 MBP1???syn mice and 11 wild?type mice aged 9 months for radiotelemetry. Animals were tested with atropine, metoprolol, clonidine, and trimethaphan at 9 and 12 months age. We applied spectral and cross?spectral analysis to assess heart rate (HR) and BP variability. At 9 months of age daytime BP (transgenic: 101 ± 2 vs. wild type: 99 ± 2 mmHg) and HR (497 ± 11 vs. 505 ± 16 beats/min) were similar. Circadian BP and HR rhythms were maintained. Nighttime BP (109 ± 2 vs. 108 ± 2 mmHg) and HR (575 ± 15 vs. 569 ± 14 beats/min), mean arterial BP responses to trimethaphan (?21 ± 8 vs. ?10 ± 5 mmHg, P = 0.240) and to clonidine (?8 ± 3 vs. ?5 ± 2 mmHg, P = 0.314) were similar. HR responses to atropine (+159 ± 24 vs. +146 ± 22 beats/min), and to clonidine (?188 ± 21 vs. ?163 ± 33 beats/min) did not differ between strains. Baroreflex sensitivity (4 ± 1 vs. 4 ± 1 msec/mmHg) and HR variability (total power, 84 ± 17 vs. 65 ± 21 msec²) were similar under resting conditions and during pharmacological testing. Repeated measurements at 12 months of age provided similar results. In mice, moderate overexpression of human alpha?synuclein in oligodendrocytes is not sufficient to induce overt autonomic failure. Additional mechanisms may be required to express the autonomic failure phenotype including higher levels of expression or more advanced age. PMID:25428949

Tank, Jens; da Costa?Goncalves, Andrey C.; Kamer, Ilona; Qadri, Fatimunnisa; Ubhi, Kiren; Rockenstein, Edward; Diedrich, André; Masliah, Eliezer; Gross, Volkmar; Jordan, Jens

2014-01-01

53

Refractory Classical Hodgkin Lymphoma Presenting with Atypical Cutaneous Involvement and Diagnosis of ZZ Phenotype Alpha-1 Antitrypsin Deficiency  

PubMed Central

Cutaneous Hodgkin lymphoma is a rare condition. Specific neoplastic involvement can be primary (confined to the skin) or secondary to systemic involvement (metastatic). Cutaneous involvement by HL usually occurs late in the course and is associated with poor prognosis; however in some cases it can exhibit indolent behavior. Skin involvement with nonspecific cutaneous findings may represent a paraneoplastic syndrome. We describe a case of 46-year-old white male patient presented with rash and lymphadenopathy which led to the diagnosis of stage IVE mixed cellularity classical Hodgkin lymphoma with skin involvement. His disease was refractory to multiple lines of chemotherapy including (1) AVD (doxorubicin/bleomycin/dacarbazine), (2) brentuximab, and (3) bendamustine, he later achieved complete remission with (4) GCD (gemcitabine/carboplatin/dexamethasone) salvage regimen. Bleomycin was not given secondary to poor pulmonary function tests. His treatment was complicated after AVD with multiple pneumothoraces which unmasked the diagnosis of ZZ phenotype alpha-1 antitrypsin (ATT) deficiency. Simultaneous existence of Hodgkin lymphoma and ATT is rarely reported. PMID:24955265

Kraus, Teresa; Cherry, Mohamad

2014-01-01

54

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

PubMed

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. PMID:416942

Itil, T M

1978-03-01

55

[Prognostic value of EEG in acute posttraumatic coma (author's transl)].  

PubMed

To evaluate the prognostic power of a single EEG-record, the recordings of 50 patients with posttraumatic coma performed within 48 hours after the injury were compared with the outcome after 6 months. A 5-point scale comprising 2 EEG-patterns being notorious for their dismal prognostic significance (suppression bursts, alpha-coma) and changes of vigilance were used as a mean of visual assessment of the recordings. In 24 out of the 28 patients with a bad outcome, the EEG had shown the patterns of category I, II and III (suppression bursts, alpha coma, no changes of vigilance). Of the 22 patients with a good outcome, the EEG had been classified as IV or V (clearly discernible changes of vigilance, sleep patterns). Further findings of particular dismal prognostic significance were focal epileptic discharges, as 9 out of the 11 patients with this EEG pattern had not survived the posttraumatic coma for more than 6 months. PMID:6800765

Walser, H; Friedli, W; Glinz, W

1981-12-01

56

Mobile EEG in epilepsy.  

PubMed

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 to these recordings, their use is still not introduced everywhere. We surveyed Dutch neurologists and patients and evaluated a novel mobile EEG device (Mobita, TMSi). Key specifications were compared with three other current mobile EEG devices. We shortly discuss algorithms to assist in the review process. Thirty percent (33 out of 109) of Dutch neurologists reported that home EEG recordings are used in their hospital. The majority of neurologists think that mobile EEG can have additional value in investigation of unclear paroxysms, but not in the initial diagnosis after a first seizure. Poor electrode contacts and signal quality, limited recording time and absence of software for reliable and effective assistance in the interpretation of EEGs have been important constraints for usage, but in recent devices discussed here, many of these problems have been solved. The majority of our patients were satisfied with the home EEG procedure and did not think that our EEG device was uncomfortable to wear, but they did feel uneasy wearing it in public. PMID:24060755

Askamp, Jessica; van Putten, Michel J A M

2014-01-01

57

The induction of the lupus phenotype by estrogen is via an estrogen receptor-alpha-dependent pathway.  

PubMed

In order to investigate the roles of ER subtypes in the estrogen-induced lupus phenotype, ERalpha-deficient (ERalpha(-/-)) and wild-type mice (WT) were injected monthly with estradiol (E-2) starting at 8 weeks. In WT mice, E-2 treatment induced a lupus phenotype, with accelerated death and increased kidney damage, as well as Th2-type serum cytokine and autoantibody production. In contrast, only minimal changes were observed in ERalpha(-/-) mice after E-2 treatment. In a separate study, we found that in immune cells of autoimmune-prone SNF(1) and non-autoimmune DBF(1) mice, both ERalpha and ERbeta were differentially expressed and modulated by E-2. In SNF(1) mice, there were more CD4(+) and CD8(+) T cells constitutively expressing ERalpha, and the percentages of ERalpha+ dendritic cells and macrophages were increased after E-2 exposure compared to DBF(1) mice. Taken together, these observations strongly suggest a role for ERalpha in E-2-induced development of the lupus phenotype. PMID:19926524

Feng, Feng; Nyland, Jennifer; Banyai, Michelle; Tatum, Arthur; Silverstone, Allen E; Gavalchin, Jerrie

2010-02-01

58

Seizures and EEG features in 74 patients with genetic-dysmorphic syndromes.  

PubMed

Epilepsy is one of the most common findings in chromosome aberrations. Types of seizures and severity may significantly vary both between different conditions and within the same aberration. Hitherto specific seizures and EEG patterns are identified for only few syndromes. We studied 74 patients with defined genetic-dysmorphic syndromes with and without epilepsy in order to assess clinical and electroencephalographic features, to compare our observation with already described electro-clinical phenotypes, and to identify putative electroencephalographic and/or seizure characteristics useful to address the diagnosis. In our population, 10 patients had chromosomal disorders, 19 microdeletion or microduplication syndromes, and 32 monogenic syndromes. In the remaining 13, syndrome diagnosis was assessed on clinical grounds. Our study confirmed the high incidence of epilepsy in genetic-dysmorphic syndromes. Moreover, febrile seizures and neonatal seizures had a higher incidence compared to general population. In addition, more than one third of epileptic patients had drug-resistant epilepsy. EEG study revealed poor background organization in 42 patients, an excess of diffuse rhythmic activities in beta, alpha or theta frequency bands in 34, and epileptiform patterns in 36. EEG was completely normal only in 20 patients. No specific electro-clinical pattern was identified, except for inv-dup15, Angelman, and Rett syndromes. Nevertheless some specific conditions are described in detail, because of notable differences from what previously reported. Regarding the diagnostic role of EEG, we found that--even without any epileptiform pattern--the generation of excessive rhythmic activities in different frequency bandwidths might support the diagnosis of a genetic syndrome. PMID:25257908

Alfei, Enrico; Raviglione, Federico; Franceschetti, Silvana; D'Arrigo, Stefano; Milani, Donatella; Selicorni, Angelo; Riva, Daria; Zuffardi, Orsetta; Pantaleoni, Chiara; Binelli, Simona

2014-12-01

59

Modification of EEG power spectra and EEG connectivity in autobiographical memory: a sLORETA study.  

PubMed

The aim of the present study was to explore the modifications of scalp EEG power spectra and EEG connectivity during the autobiographical memory test (AM-T) and during the retrieval of an autobiographical event (the high school final examination, Task 2). Seventeen healthy volunteers were enrolled (9 women and 8 men, mean age 23.4 ± 2.8 years, range 19-30). EEG was recorded at baseline and while performing the autobiographical memory (AM) tasks, by means of 19 surface electrodes and a nasopharyngeal electrode. EEG analysis was conducted by means of the standardized LOw Resolution Electric Tomography (sLORETA) software. Power spectra and lagged EEG coherence were compared between EEG acquired during the memory tasks and baseline recording. The frequency bands considered were as follows: delta (0.5-4 Hz); theta (4.5-7.5 Hz); alpha (8-12.5 Hz); beta1 (13-17.5 Hz); beta2 (18-30 Hz); gamma (30.5-60 Hz). During AM-T, we observed a significant delta power increase in left frontal and midline cortices (T = 3.554; p < 0.05) and increased EEG connectivity in delta band in prefrontal, temporal, parietal, and occipital areas, and for gamma bands in the left temporo-parietal regions (T = 4.154; p < 0.05). In Task 2, we measured an increased power in the gamma band located in the left posterior midline areas (T = 3.960; p < 0.05) and a significant increase in delta band connectivity in the prefrontal, temporal, parietal, and occipital areas, and in the gamma band involving right temporo-parietal areas (T = 4.579; p < 0.05). These results indicate that AM retrieval engages in a complex network which is mediated by both low- (delta) and high-frequency (gamma) EEG bands. PMID:24610490

Imperatori, Claudio; Brunetti, Riccardo; Farina, Benedetto; Speranza, Anna Maria; Losurdo, Anna; Testani, Elisa; Contardi, Anna; Della Marca, Giacomo

2014-08-01

60

Motivational mechanisms (BAS) and prefrontal cortical activation contribute to recognition memory for emotional words. rTMS effect on performance and EEG (alpha band) measures.  

PubMed

The present research addressed the question of where memories for emotional words could be represented in the brain. A second main question was related to the effect of personality traits, in terms of the Behavior Activation System (BAS), in emotional word recognition. We tested the role of the left DLPFC (LDLPFC) by performing a memory task in which old (previously encoded targets) and new (previously not encoded distractors) positive or negative emotional words had to be recognized. High-BAS and low-BAS subjects were compared when a repetitive TMS (rTMS) was applied on the LDLPFC. We found significant differences between high-BAS vs. low-BAS subjects, with better performance for high-BAS in response to positive words. In parallel, an increased left cortical activity (alpha desynchronization) was observed for high-BAS in the case of positive words. Thus, we can conclude that the left approach-related hemisphere, underlying BAS, may support faster recognition of positive words. PMID:25190327

Balconi, Michela; Cobelli, Chiara

2014-10-01

61

Novel active comb-shaped dry electrode for EEG measurement in hairy site.  

PubMed

Electroencephalography (EEG) is an important biopotential, and has been widely applied in clinical applications. The conventional EEG electrode with conductive gels is usually used for measuring EEG. However, the use of conductive gel also encounters with the issue of drying and hardening. Recently, many dry EEG electrodes based on different conductive materials and techniques were proposed to solve the previous issue. However, measuring EEG in the hairy site is still a difficult challenge. In this study, a novel active comb-shaped dry electrode was proposed to measure EEG in hairy site. Different form other comb-shaped or spike-shaped dry electrodes, it can provide more excellent performance of avoiding the signal attenuation, phase distortion, and the reduction of common mode rejection ratio. Even under walking motion, it can effectively acquire EEG in hairy site. Finally, the experiments for alpha rhythm and steady-state visually evoked potential were also tested to validate the proposed electrode. PMID:25137719

Huang, Yan-Jun; Wu, Chung-Yu; Wong, Alice May-Kuen; Lin, Bor-Shyh

2015-01-01

62

BOLD Response and EEG Gamma Oscillations  

Microsoft Academic Search

\\u000a The rhythmic activities in the resting or “spontaneous” EEG are usually divided into several frequency bands (delta: <4 Hz;\\u000a theta: 4–8 Hz; alpha: 8–12 Hz; beta: 12–30 Hz; and gamma: 30–70 Hz or higher, centred at 40 Hz), which are associated with\\u000a different behavioural states, ranging from sleep to relaxation, heightened alertness and mental concentration (Lindsley 1952;\\u000a Niedermeyer and Lopes

Gregor Leicht; Christoph S. Herrmann; Christoph Mulert

63

EEG findings during special psychical state (Qi Gong state) by means of compressed spectral array and topographic mapping.  

PubMed

Wallace first reported the changes in EEG during transcendental mediation [6]. Banquet [1] observed, on the basis of spectral analysis of the EEG, that the mediation state was a unique state of consciousness, and separate from wakefulness, drowsiness or sleep. The Qi Gong of China is not the same as either transcendental mediation or the Yoga Gong. The EEG during Qi Gong state is clearly different from those recorded during the resting state. The changes in the EEG during the Qi Gong have not been reported previously. The EEG alpha activity during the Qi Gong state occurs predominantly in the anterior regions. The peak frequency of EEG alpha rhythm is slower than the resting state. The change of EEG during Qi Gong between anterior and posterior half is negative correlation. These changes are statistically significant. PMID:3060312

Zhang, J Z; Zhao, J; He, Q N

1988-01-01

64

Identifying Periods of Drowsy Driving Using EEG  

PubMed Central

Drowsy driving is a significant contributor to death and injury crashes on our nation’s highways. Predictive neurophysiologic/physiologic solutions to reduce these incidences have been proposed and developed. EEG based metrics were found to be promising in initial studies, but remain controversial in their efficacy, primarily due to failures to develop replication studies within the simulation settings used for development, and real-world validation. This analysis sought to address these short comings by assessing the utility of the B-Alert algorithms, in a replication study of driving and drowsiness. Data were collected on the National Advanced Driving Simulator from 72 volunteer drivers exposed to three types of roadways at three times of day representing different levels of drowsiness. EEG metrics, collected using the B-Alert X10 Wireless Headset were evaluated to determine their utility in future predictive studies. The replication of the B-Alert algorithms was a secondary focus for this analysis, resulting in highly variable start times within each time of day segment, leading to EEG data being confounded by the diurnal variations that occur in the basal EEG signal. Regardless of this limitation, the analysis revealed promising outcomes. The EEG based algorithms for sleep onset, drowsiness, as well as fatigue related power spectral bandwidths (i.e. lateral central, and parietal alpha) varied with time of day of the drives. Interestingly, EEG metrics of cognitive workload were also sensative to the terrain of the drives. The replicaiton of the B-Alert algorithms were a secondary focuse in the study design, Taken together, these data indicate great potential of carefully designed studies to utilize neurophysiologic metrics to identify time of day and task and road conditions that may be at greatest risk during fatigued/drowsy periods. PMID:24406950

Brown, Timothy; Johnson, Robin; Milavetz, Gary

2013-01-01

65

Identifying periods of drowsy driving using EEG.  

PubMed

Drowsy driving is a significant contributor to death and injury crashes on our nation's highways. Predictive neurophysiologic/physiologic solutions to reduce these incidences have been proposed and developed. EEG based metrics were found to be promising in initial studies, but remain controversial in their efficacy, primarily due to failures to develop replication studies within the simulation settings used for development, and real-world validation. This analysis sought to address these short comings by assessing the utility of the B-Alert algorithms, in a replication study of driving and drowsiness. Data were collected on the National Advanced Driving Simulator from 72 volunteer drivers exposed to three types of roadways at three times of day representing different levels of drowsiness. EEG metrics, collected using the B-Alert X10 Wireless Headset were evaluated to determine their utility in future predictive studies. The replication of the B-Alert algorithms was a secondary focus for this analysis, resulting in highly variable start times within each time of day segment, leading to EEG data being confounded by the diurnal variations that occur in the basal EEG signal. Regardless of this limitation, the analysis revealed promising outcomes. The EEG based algorithms for sleep onset, drowsiness, as well as fatigue related power spectral bandwidths (i.e. lateral central, and parietal alpha) varied with time of day of the drives. Interestingly, EEG metrics of cognitive workload were also sensative to the terrain of the drives. The replicaiton of the B-Alert algorithms were a secondary focuse in the study design, Taken together, these data indicate great potential of carefully designed studies to utilize neurophysiologic metrics to identify time of day and task and road conditions that may be at greatest risk during fatigued/drowsy periods. PMID:24406950

Brown, Timothy; Johnson, Robin; Milavetz, Gary

2013-01-01

66

Response of Hepatitis C Virus to Long-Term Passage in the Presence of Alpha Interferon: Multiple Mutations and a Common Phenotype  

PubMed Central

Cell culture-produced hepatitis C virus (HCV) has been subjected to up to 100 serial passages in human hepatoma cells in the absence or presence of different doses of alpha interferon (IFN-?). Virus survival, genetic changes, fitness levels, and phenotypic traits have been examined. While high initial IFN-? doses (increasing from 1 to 4 IU/ml) did not allow HCV survival beyond passage 40, a gradual exposure (from 0.25 to 10 IU/ml) allowed the virus to survive for at least 100 passages. The virus passaged in the presence of IFN-? acquired IFN-? resistance as evidenced by enhanced progeny production and viral protein expression in an IFN-? environment. A partial IFN-? resistance was also noted in populations passaged in the absence of IFN-?. All lineages acquired adaptative mutations, and multiple, nonsynonymous mutations scattered throughout the genome were present in IFN-?-selected populations. Comparison of consensus sequences indicates a dominance of synonymous versus nonsynonymous substitutions. IFN-?-resistant populations displayed decreased sensitivity to a combination of IFN-? and ribavirin. A phenotypic trait common to all assayed viral populations is the ability to increase shutoff host cell protein synthesis, accentuated in infections with IFN-?-selected populations carried out in the presence of IFN-?. The trait was associated with enhanced phosphorylation of protein kinase R (PKR) and eIF2?, although other contributing factors are likely. The results suggest that multiple, independent mutational pathways can confer IFN-? resistance to HCV and might explain why no unified picture has been obtained regarding IFN-? resistance in vivo. PMID:23637397

Perales, Celia; Beach, Nathan M.; Gallego, Isabel; Soria, Maria Eugenia; Quer, Josep; Esteban, Juan Ignacio; Rice, Charles

2013-01-01

67

Genetic analysis of the pathogenic molecular sub-phenotype interferon-alpha identifies multiple novel loci involved in systemic lupus erythematosus.  

PubMed

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by inflammation of multiple organ systems and dysregulated interferon responses. SLE is both genetically and phenotypically heterogeneous, greatly reducing the power of case-control studies in SLE. Elevated circulating interferon-alpha (IFN-?) is a stable, heritable trait in SLE, which has been implicated in primary disease pathogenesis. About 40-50% of patients have high IFN-?, and high levels correspond with clinical differences. To study genetic heterogeneity in SLE, we performed a case-case study comparing patients with high vs low IFN-? in over 1550 SLE cases, including genome-wide association study and replication cohorts. In meta-analysis, the top associations in European ancestry were protein kinase, cyclic GMP-dependent, type I (PRKG1) rs7897633 (PMeta=2.75 × 10(-8)) and purine nucleoside phosphorylase (PNP) rs1049564 (PMeta=1.24 × 10(-7)). We also found evidence for cross-ancestral background associations with the ankyrin repeat domain 44 (ANKRD44) and pleckstrin homology domain containing, family F member 2 gene (PLEKHF2) loci. These loci have not been previously identified in case-control SLE genetic studies. Bioinformatic analyses implicated these loci functionally in dendritic cells and natural killer cells, both of which are involved in IFN-? production in SLE. As case-control studies of heterogeneous diseases reach a limit of feasibility with respect to subject number and detectable effect size, the study of informative pathogenic sub-phenotypes becomes an attractive strategy for genetic discovery in complex disease.Genes and Immunity advance online publication, 23 October 2014; doi:10.1038/gene.2014.57. PMID:25338677

Kariuki, S N; Ghodke-Puranik, Y; Dorschner, J M; Chrabot, B S; Kelly, J A; Tsao, B P; Kimberly, R P; Alarcón-Riquelme, M E; Jacob, C O; Criswell, L A; Sivils, K L; Langefeld, C D; Harley, J B; Skol, A D; Niewold, T B

2014-10-23

68

From EEG to BOLD: brain mapping and estimating transfer functions in simultaneous EEG-fMRI acquisitions.  

PubMed

Simultaneous acquisition of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) aims to disentangle the description of brain processes by exploiting the advantages of each technique. Most studies in this field focus on exploring the relationships between fMRI signals and the power spectrum at some specific frequency bands (alpha, beta, etc.). On the other hand, brain mapping of EEG signals (e.g., interictal spikes in epileptic patients) usually assumes an haemodynamic response function for a parametric analysis applying the GLM, as a rough approximation. The integration of the information provided by the high spatial resolution of MR images and the high temporal resolution of EEG may be improved by referencing them by transfer functions, which allows the identification of neural driven areas without strong assumptions about haemodynamic response shapes or brain haemodynamic's homogeneity. The difference on sampling rate is the first obstacle for a full integration of EEG and fMRI information. Moreover, a parametric specification of a function representing the commonalities of both signals is not established. In this study, we introduce a new data-driven method for estimating the transfer function from EEG signal to fMRI signal at EEG sampling rate. This approach avoids EEG subsampling to fMRI time resolution and naturally provides a test for EEG predictive power over BOLD signal fluctuations, in a well-established statistical framework. We illustrate this concept in resting state (eyes closed) and visual simultaneous fMRI-EEG experiments. The results point out that it is possible to predict the BOLD fluctuations in occipital cortex by using EEG measurements. PMID:20116435

Sato, João R; Rondinoni, Carlo; Sturzbecher, Marcio; de Araujo, Draulio B; Amaro, Edson

2010-05-01

69

In search of biomarkers in psychiatry: EEG-based measures of brain function.  

PubMed

Current clinical parameters used for diagnosis and phenotypic definitions of psychopathology are both highly variable and subjective. Intensive research efforts for specific and sensitive biological markers, or biomarkers, for psychopathology as objective alternatives to the current paradigm are ongoing. While biomarker research in psychiatry has focused largely on functional neuroimaging methods for identifying the neural functions that associate with psychopathology, scalp electroencephalography (EEG) has been viewed, historically, as offering little specific brain source information, as scalp appearance is only loosely correlated to its brain source dynamics. However, ongoing advances in signal processing of EEG data can now deliver functional EEG brain-imaging with distinctly improved spatial, as well as fine temporal, resolution. One computational approach proving particularly useful for EEG cortical brain imaging is independent component analysis (ICA). ICA decomposition can be used to identify distinct cortical source activities that are sensitive and specific to the pathophysiology of psychiatric disorders. Given its practical research advantages, relatively low cost, and ease of use, EEG-imaging is now both feasible and attractive, in particular for studies involving the large samples required by genetically informative designs to characterize causal pathways to psychopathology. The completely non-invasive nature of EEG data acquisition, coupled with ongoing advances in dry, wireless, and wearable EEG technology, makes EEG-imaging increasingly attractive and appropriate for psychiatric research, including the study of developmentally young samples. Applied to large genetically and developmentally informative samples, EEG imaging can advance the search for robust diagnostic biomarkers and phenotypes in psychiatry. PMID:24273134

McLoughlin, Gráinne; Makeig, Scott; Tsuang, Ming T

2014-03-01

70

Correlates of alpha rhythm in functional magnetic resonance imaging and near infrared spectroscopy  

Microsoft Academic Search

We used simultaneous electroencephalogram-functional magnetic resonance imaging (EEG-fMRI) and EEG-near infrared spectroscopy (NIRS) to investigate whether changes of the posterior EEG alpha rhythm are correlated with changes in local cerebral blood oxygenation. Cross-correlation analysis of slowly fluctuating, spontaneous rhythms in the EEG and the fMRI signal revealed an inverse relationship between alpha activity and the fMRI-blood oxygen level dependent signal

Matthias Moosmann; Petra Ritter; Ina Krastel; Andrea Brink; Sebastian Thees; Felix Blankenburg; Birol Taskin; Hellmuth Obrig; Arno Villringer

2003-01-01

71

EEG patterns in persons exposed to ionizing radiation as a result of the Chernobyl accident: part 1: conventional EEG analysis.  

PubMed

Prospective conventional EEG study was carried out 3-5 and 10-13 years after the Chernobyl accident (1986) in patients who had acute radiation sickness and in emergency workers in 1986 ("liquidators"). Control groups comprised healthy volunteers; veterans of the Afghanistan war with posttraumatic stress disorder; veterans with mild traumatic brain injury; and patients with dyscirculatory encephalopathy. In 3-5 years after irradiation, there were irritated EEG changes with paroxysmal activity shifted to the left frontotemporal region (cortical-limbic overactivation) that were transformed 10-13 years after irradiation toward a low-voltage EEG pattern with excess of fast (beta) and slow (delta) activity together with depression of alpha and theta activity (organic brain damage with inhibition of the cortical-limbic system). Quantitative EEG is likely to be very informative for investigation of dose-effect relationships. PMID:11748314

Loganovsky, K N; Yuryev, K L

2001-01-01

72

Interindividual Differences in Alpha and Theta Power Reflect Memory Performance.  

ERIC Educational Resources Information Center

Tested whether tonic EEG power is related to memory performance by analyzing ongoing EEG for 60 subjects in 5 experimental conditions. Subjects with good memory performance had significantly larger upper alpha power, but less theta and lower alpha power. Also discusses findings for subjects good at calculation. (SLD)

Klimesch, W.; Vogt, F.; Doppelmayr, M.

1999-01-01

73

EEG manifestations of nondual experiences in meditators.  

PubMed

The holistic experiential benefits of meditation among a widely ranging population have been well established within the empirical literature. What remain less clear are the underlying mechanisms of the meditative process. A large impediment to this clarity is attributable to the lack of a unified and comprehensive taxonomy, as well as to the absence of clear differentiation within the literature between method of practice and resulting state. The present study discusses and then attempts to identify within our sample a theoretically universal culminating meditative state known as Nondual Awareness, which is differentiated from the method or practice state. Participants completed an in-lab meditation, during which neurological patterns were analyzed using electroencephalography (EEG). Analyses indicated significantly higher EEG power among slower wave frequencies (delta, theta, alpha) during the reported nondual events. These events appear neurologically distinct from meditation sessions as a whole, which interestingly demonstrated significant elevation within the gamma range. PMID:25460236

Berman, Amanda E; Stevens, Larry

2015-01-01

74

Large spectrum of lissencephaly and pachygyria phenotypes resulting from de novo missense mutations in tubulin alpha 1A (TUBA1A).  

PubMed

We have recently reported a missense mutation in exon 4 of the tubulin alpha 1A (Tuba1a) gene in a hyperactive N-ethyl-N-nitrosourea (ENU) induced mouse mutant with abnormal lamination of the hippocampus. Neuroanatomical similarities between the Tuba1a mutant mouse and mice deficient for Doublecortin (Dcx) and Lis1 genes, and the well-established functional interaction between DCX and microtubules (MTs), led us to hypothesize that mutations in TUBA1A (TUBA3, previous symbol), the human homolog of Tuba1a, might give rise to cortical malformations. This hypothesis was subsequently confirmed by the identification of TUBA1A mutations in two patients with lissencephaly and pachygyria, respectively. Here we report additional TUBA1A mutations identified in six unrelated patients with a large spectrum of brain dysgeneses. The de novo occurrence was shown for all mutations, including one recurrent mutation (c.790C>T, p.R264C) detected in two patients, and two mutations that affect the same amino acid (c.1205G>A, p.R402H; c.1204C>T, p.R402C) detected in two other patients. Retrospective examination of MR images suggests that patients with TUBA1A mutations share not only cortical dysgenesis, but also cerebellar, hippocampal, corpus callosum, and brainstem abnormalities. Interestingly, the specific high level of Tuba1a expression throughout the period of central nervous system (CNS) development, shown by in situ hybridization using mouse embryos, is in accordance with the brain-restricted developmental phenotype caused by TUBA1A mutations. All together, these results, in combination with previously reported data, strengthen the relevance of the known interaction between MTs and DCX, and highlight the importance of the MTs/DCX complex in the neuronal migration process. PMID:17584854

Poirier, Karine; Keays, David A; Francis, Fiona; Saillour, Yoann; Bahi, Nadia; Manouvrier, Sylvie; Fallet-Bianco, Catherine; Pasquier, Laurent; Toutain, Annick; Tuy, Françoise Phan Dinh; Bienvenu, Thierry; Joriot, Sylvie; Odent, Sylvie; Ville, Dorothée; Desguerre, Isabelle; Goldenberg, Alice; Moutard, Marie-Laure; Fryns, Jean-Pierre; van Esch, Hilde; Harvey, Robert J; Siebold, Christian; Flint, Jonathan; Beldjord, Chérif; Chelly, Jamel

2007-11-01

75

Technical advantages of digital EEG.  

PubMed

Digital EEG (DEEG) is the paperless recording of an EEG using computer-based instrumentation. The data are stored on electronic media, such as magnetic drives or optical disks, and displayed on a monitor. DEEG has many advantages compared to analog EEG including automatic event detection, storage, quantification, and networking capabilities. The flexibility of DEEG allows for changes of recording parameters, such as montage, filters, and horizontal and vertical display scales retrospectively during record review. In this review numerous clinical EEG examples are used to demonstrate how these post hoc changes, particularly reformatting the montage, allow for more accurate interpretation of the EEG. PMID:9881917

Van Cott, A; Brenner, R P

1998-11-01

76

Electroencephalogram (EEG) (For Parents)  

MedlinePLUS

... of the brain. This procedure tracks and records brain wave patterns. Small metal discs with thin wires (electrodes) are placed on the scalp, and then send signals to a computer to record the results. Normal electrical activity in the brain makes a recognizable pattern. Through an EEG, doctors ...

77

Atypical Alpha Asymmetry in Adults with ADHD  

ERIC Educational Resources Information Center

Introduction: A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha

Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

2009-01-01

78

EEG activity during the performance of complex mental problems.  

PubMed

This study investigated differences in cognitive processes related to problem complexity. It was assumed that these differences would be reflected in respondents' EEG activity--spectral power and coherence. A second issue of the study was to compare differences between the lower (alpha(1) = 7.9-10.0 Hz), and upper alpha band (alpha(2) = 10.1-12.9 Hz). In the first experiment two well-defined problems with two levels of complexity were used. Only minor differences in EEG power and coherence measures related to problem complexity were observed. In the second experiment divergent production problems resembling tasks on creativity tests were compared with dialectic problems calling for creative solutions. Differences in EEG power measures were mainly related to the form of problem presentation (figural/verbal). In contrast, coherence was related to the level of creativity needed to solve a problem. Noticeable increased intra- and interhemispheric cooperation between mainly the far distant brain regions was observed in the EEG activity of respondents while solving the dialectic problems. These results are explained by the more intense involvement of the long cortico-cortical fiber system in creative thinking. Differences between the lower and upper alpha band were significant for the power and coherence measures. In Experiment 2, fewer differences were observed in power measures in the upper alpha band than in the lower alpha band. A reverse pattern was observed for the coherence measures. These results hint to a functional independence of the two alpha bands, however, they do not allow to draw firm conclusions about their functional meanings. The study showed that it is unlikely that individuals solve well- and ill-defined problems by employing similar cognitive strategies. PMID:10700625

Jausovec, N; Jausovec, K

2000-04-01

79

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

PubMed

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 electrophysiological signature created by combination of different brain rhythms subserving different putative functions. PMID:24505434

Neuner, Irene; Arrubla, Jorge; Werner, Cornelius J; Hitz, Konrad; Boers, Frank; Kawohl, Wolfram; Shah, N Jon

2014-01-01

80

The Default Mode Network and EEG Regional Spectral Power: A Simultaneous fMRI-EEG Study  

PubMed Central

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 electrophysiological signature created by combination of different brain rhythms subserving different putative functions. PMID:24505434

Werner, Cornelius J.; Hitz, Konrad; Boers, Frank; Kawohl, Wolfram; Shah, N. Jon

2014-01-01

81

High frequency waking EEG: reflection of a slow ultradian rhythm in daytime arousal.  

PubMed

The ultradian dynamics of the human waking EEG was studied using a short visual fixation task repeated every 10 min throughout the daytime. The EEG spectra obtained from the tasks were assessed for time effect and ultradian periodicity. Fronto-central EEG high frequency powers (22.5-44.5 Hz) decreased at the time of the midafternoon vigilance dip (14.00-17.00 h) along with slight concomitant increases in parietal alpha (7.5-13.5 Hz) and delta (1-3 Hz) powers. A slow ultradian rhythm with a 3-4 h periodicity strongly modulated EEG power in all frequency bands between 1 and 44.5 Hz. The high frequency waking EEG may well reflect the activity of a brain arousal process underlying maintenance of the waking state probably throughout the 24 h cycle. PMID:10923675

Chapotot, F; Jouny, C; Muzet, A; Buguet, A; Brandenberger, G

2000-07-14

82

Wavelet packet analysis of EEG signals from dyslexic children with writing disability.  

PubMed

This paper describes Wavelet Packet Analysis of EEG signal of dyslexic children with writing disability. Two activities were carried out during EEG recordings; relax and and writing letters. EEG signals were collected using biosignal gMobilab system and analysed using Wavelet Packet Decomposition to extract alpha and beta brainwave rhythm. Statistical data such as log energy entropy and standard deviation were used to compare the characteristic of EEG signals from dyslexic and normal children. Result showed that the dyslexic children consumed higher energy at left parietal lobe during writing activity especially those who write incorrectly. The alpha band shows higher log energy entropy for dyslexic children compare to normal children at most channel during relax. PMID:24110331

Fuad, N; Mansor, W; Lee, Khuan Y

2013-01-01

83

EEG biofeedback improves attentional bias in high trait anxiety individuals  

PubMed Central

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 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. Conclusion 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. PMID:24099141

2013-01-01

84

EEG of Chronic Marijuana Users during Abstinence: Relationship to Years of Marijuana Use, Cerebral Blood Flow and Thyroid Function  

PubMed Central

Objective Marijuana abuse is associated with neurological changes including increases in frontal EEG alpha during abstinence. Research is needed to assess to what extent these EEG patterns are indicative of cerebral perfusion deficits. Methods We recorded the resting eyes closed EEG of 75 abstinent marijuana users and 33 control subjects. Fifty-six marijuana users used marijuana for less than eight years and 19 used for eight years or more. The EEG evaluation occurred within 72 hours of admission to an inpatient unit. Fifty-nine marijuana users remained abstinent for a month and were tested twice. Supplemental psychological and physiological data were also collected. Results Log alpha2 and beta2 power at posterior sites were significantly lower for the marijuana abusers that used eight years or more than the other marijuana abusers and the control subjects. These EEG changes continued for the month of abstinence. The marijuana users who used marijuana for more than eight years, also, had lower heart rates and thyroid function (T4) compared to the other marijuana users and the control subjects. Conclusions Chronic marijuana use was also associated with reduced EEG power in alpha and beta bands at posterior sites. These reductions in EEG power appear to be related to cerebral perfusion deficits and/or thyroid function in marijuana abusers. Significance Our results suggest EEG, cerebral blood flow velocity, cardiovascular and thyroid function alterations in marijuana abuser with an extended period of use. These alterations reflect under arousal in these systems. PMID:18065267

Herning, Ronald I.; Better, Warren; Cadet, Jean L.

2008-01-01

85

A pilot study to evaluate the effects of Cerebrolysin on cognition and qEEG in vascular dementia: cognitive improvement correlates with qEEG acceleration.  

PubMed

The effects of the neurotrophic compound Cerebrolysin (Cere) on cognitive performance, evaluated with the ADAS-cog, and on qEEG activity were investigated in forty one patients with mild to moderate severe probable vascular dementia (VaD) according to NINDS-AIREN criteria, included in a placebo-controlled pilot study. Patients received i.v. infusions of Cere (10 or 30 ml) or placebo (normal saline) 5 days/week for 4 weeks. Mean score of change from baseline in the ADAS-cog and percent change from baseline in slow to fast EEG power ratio (PR) scores were the two primary endpoints. Correlations between cognition and qEEG were also evaluated for both baseline scores and for scores of change from baseline in ADAS-cog and in qEEG parameters, including EEG power ratio (PR) as an index of EEG slowing. Baseline ADAS-cog scores showed significant positive correlations with delta power, theta power and PR scores, and correlated negatively with alpha activity. These correlations indicating that an increased EEG slowing is associated with a worst cognitive performance in VaD patients. Cere treatment improved cognitive performance significantly at the 10 ml dose and reduced EEG slowing with both 10 and 30 ml dosages. A significant positive correlation between PR and ADAS-cog scores of change from baseline was observed in Cere-treated patients. According to results of this pilot study, it is concluded that Cere improves cognitive performance and reduces EEG slowing in patients with VaD, and that there is a positive relationship between changes in cognition and qEEG activity induced by Cere. The conduction of further regular clinical trials is required to confirm the potential utility of Cere in the treatment of VaD suggested by the present results. PMID:18048059

Muresanu, Dafin F; Alvarez, X Anton; Moessler, Herbert; Buia, Manuel; Stan, Adina; Pintea, Daniela; Moldovan, Florina; Popescu, Bogdan O

2008-04-15

86

EEG Studies with Young Children.  

ERIC Educational Resources Information Center

Describes how electroencephalogram (EEG) data are collected and how brain function is measured. Discusses studies on the effects of music experiences with adult subjects and studies focusing on the effects of music training on EEG activity of children and adolescents. Considers the implications of the studies and the future directions of this…

Flohr, John W.; Miller, Daniel C.; deBeus, Roger

2000-01-01

87

A High Resolution Quantitative EEG Power Analysis of Obsessive-Compulsive Disorder  

Microsoft Academic Search

Introduction: The findings of the quantitative EEG power-spectral studies in obsessive-compulsive disorder (OCD) have so far been mostly inconsistent. Moreover, none of the studies has been a high resolution one. Aim: The aim of the study was to examine the band power of delta, theta, alpha, beta1 and beta2 bands with high resolution EEG data in patients with obsessive- compulsive

Pushpal Desarkar; Vinod Kumar Sinha; K. Jagadheesan; S. Haque Nizamie

88

Aberrant EEG functional connectivity and EEG power spectra in resting state post-traumatic stress disorder: a sLORETA study.  

PubMed

The aim of the present study was to explore the modifications of EEG power spectra and EEG connectivity of resting state (RS) condition in patients with post-traumatic stress disorder (PTSD). Seventeen patients and seventeen healthy subjects matched for age and gender were enrolled. EEG was recorded during 5min of RS. EEG analysis was conducted by means of the standardized Low Resolution Electric Tomography software (sLORETA). In power spectra analysis PTSD patients showed a widespread increase of theta activity (4.5-7.5Hz) in parietal lobes (Brodmann Area, BA 7, 4, 5, 40) and in frontal lobes (BA 6). In the connectivity analysis PTSD patients also showed increase of alpha connectivity (8-12.5Hz) between the cortical areas explored by Pz-P4 electrode. Our results could reflect the alteration of memory systems and emotional processing consistently altered in PTSD patients. PMID:25046862

Imperatori, Claudio; Farina, Benedetto; Quintiliani, Maria Isabella; Onofri, Antonio; Castelli Gattinara, Paola; Lepore, Marta; Gnoni, Valentina; Mazzucchi, Edoardo; Contardi, Anna; Della Marca, Giacomo

2014-10-01

89

EEG Recording and Analysis for Sleep Research  

PubMed Central

The electroencephalogram (EEG) is the most common tool used in sleep research. This unit describes the methods for recording and analyzing the EEG. Detailed protocols describe recorder calibration, electrode application, EEG recording, and computer EEG analysis with power spectral analysis. Computer digitization of an analog EEG signal is discussed, along with EEG filtering and the parameters of fast Fourier transform (FFT) power spectral analysis. Sample data are provided for a typical night's analysis of EEG during NREM (non-REM) and REM sleep. PMID:19802813

Campbell, Ian G.

2010-01-01

90

Electroencephalographic precursors of spike-wave discharges in a genetic rat model of absence epilepsy: Power spectrum and coherence EEG analyses  

Microsoft Academic Search

Periods in the electroencephalogram (EEG) that immediately precede the onset of spontaneous spike-wave discharges (SWD) were examined in WAG\\/Rij rat model of absence epilepsy. Precursors of SWD (preSWD) were classified based on the distribution of EEG power in delta-theta-alpha frequency bands as measured in the frontal cortex. In 95% of preSWD, an elevation of EEG power was detected in delta

Evgenia Sitnikova; Gilles van Luijtelaar

2009-01-01

91

EEG source imaging of brain states using spatiotemporal regression.  

PubMed

Relating measures of electroencephalography (EEG) back to the underlying sources is a long-standing inverse problem. Here we propose a new method to estimate the EEG sources of identified electrophysiological states that represent spontaneous activity, or are evoked by a stimulus, or caused by disease or disorder. Our method has the unique advantage of seamlessly integrating a statistical significance of the source estimate while efficiently eliminating artifacts (e.g., due to eye blinks, eye movements, bad electrodes). After determining the electrophysiological states in terms of stable topographies using established methods (e.g.: ICA, PCA, k-means, epoch average), we propose to estimate these states' time courses through spatial regression of a General Linear Model (GLM). These time courses are then used to find EEG sources that have a similar time-course (using temporal regression of a second GLM). We validate our method using both simulated and experimental data. Simulated data allows us to assess the difference between source maps obtained by the proposed method and those obtained by applying conventional source imaging of the state topographies. Moreover, we use data from 7 epileptic patients (9 distinct epileptic foci localized by intracranial EEG) and 2 healthy subjects performing an eyes-open/eyes-closed task to elicit activity in the alpha frequency range. Our results indicate that the proposed EEG source imaging method accurately localizes the sources for each of the electrical brain states. Furthermore, our method is particularly suited for estimating the sources of EEG resting states or otherwise weak spontaneous activity states, a problem not adequately solved before. PMID:24726337

Custo, Anna; Vulliemoz, Serge; Grouiller, Frederic; Van De Ville, Dimitri; Michel, Christoph

2014-08-01

92

An EEG Finger-Print of fMRI deep regional activation.  

PubMed

This work introduces a general framework for producing an EEG Finger-Print (EFP) which can be used to predict specific brain activity as measured by fMRI at a given deep region. This new approach allows for improved EEG spatial resolution based on simultaneous fMRI activity measurements. Advanced signal processing and machine learning methods were applied on EEG data acquired simultaneously with fMRI during relaxation training guided by on-line continuous feedback on changing alpha/theta EEG measure. We focused on demonstrating improved EEG prediction of activation in sub-cortical regions such as the amygdala. Our analysis shows that a ridge regression model that is based on time/frequency representation of EEG data from a single electrode, can predict the amygdala related activity significantly better than a traditional theta/alpha activity sampled from the best electrode and about 1/3 of the times, significantly better than a linear combination of frequencies with a pre-defined delay. The far-reaching goal of our approach is to be able to reduce the need for fMRI scanning for probing specific sub-cortical regions such as the amygdala as the basis for brain-training procedures. On the other hand, activity in those regions can be characterized with higher temporal resolution than is obtained by fMRI alone thus revealing additional information about their processing mode. PMID:24246494

Meir-Hasson, Yehudit; Kinreich, Sivan; Podlipsky, Ilana; Hendler, Talma; Intrator, Nathan

2014-11-15

93

CNT/PDMS-based canal-typed ear electrodes for inconspicuous EEG recording  

NASA Astrophysics Data System (ADS)

Objective. Current electroencephalogram (EEG) monitoring systems typically require cumbersome electrodes that must be pasted on a scalp, making a private recording of an EEG in a public place difficult. We have developed a small, user friendly, biocompatible electrode with a good appearance for inconspicuous EEG monitoring. Approach. We fabricated carbon nanotube polydimethylsiloxane (CNT/PDMS)-based canal-type ear electrodes (CEE) for EEG recording. These electrodes have an additional function, triggering sound stimulation like earphones and recording EEG simultaneously for auditory brain-computer interface (BCI). The electrode performance was evaluated by a standard EEG measurement paradigm, including the detection of alpha rhythms and measurements of N100 auditory evoked potential (AEP), steady-state visual evoked potential (SSVEP) and auditory steady-state response (ASSR). Furthermore, the bio- and skin-compatibility of CNT/PDMS were tested. Main results. All feasibility studies were successfully recorded with the fabricated electrodes, and the biocompatibility of CNT/PDMS was also proved. Significance. These electrodes could be used to monitor EEG clinically, in ubiquitous health care and in brain-computer interfaces.

Lee, Joong Hoon; Lee, Seung Min; Byeon, Hang Jin; Hong, Joung Sook; Park, Kwang Suk; Lee, Sang-Hoon

2014-08-01

94

Effect of Low-Level Laser Stimulation on EEG  

PubMed Central

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. PMID:22973409

Wu, Jih-Huah; Chang, Wen-Dien; Hsieh, Chang-Wei; Jiang, Joe-Air; Fang, Wei; Shan, Yi-Chia; Chang, Yang-Chyuan

2012-01-01

95

Combined testing for CCAAT\\/enhancer-binding protein alpha (CEBPA) mutations and promoter methylation in acute myeloid leukemia demonstrates shared phenotypic features  

Microsoft Academic Search

Loss of function mutations in CCAAT\\/enhancer binding protein alpha (CEBPA) have been identified in acute myeloid leukemia (AML) and bi-allelic (double) CEBPA mutations are associated with improved prognosis in cases of cytogenetically normal-AML. In a subset of AML patients lacking CEBPA mutations, core promotor methylation of CEBPA has been described and is associated with a gene expression profile similar to

Philippe Szankasi; Albert K. Ho; David W. Bahler; Olga Efimova; Todd W. Kelley

2011-01-01

96

Monitoring task loading with multivariate EEG measures during complex forms of human-computer interaction  

NASA Technical Reports Server (NTRS)

Electroencephalographic (EEG) recordings were made while 16 participants performed versions of a personal-computer-based flight simulation task of low, moderate, or high difficulty. As task difficulty increased, frontal midline theta EEG activity increased and alpha band activity decreased. A participant-specific function that combined multiple EEG features to create a single load index was derived from a sample of each participant's data and then applied to new test data from that participant. Index values were computed for every 4 s of task data. Across participants, mean task load index values increased systematically with increasing task difficulty and differed significantly between the different task versions. Actual or potential applications of this research include the use of multivariate EEG-based methods to monitor task loading during naturalistic computer-based work.

Smith, M. E.; Gevins, A.; Brown, H.; Karnik, A.; Du, R.

2001-01-01

97

Study on EEG power and coherence in patients with mild cognitive impairment during working memory task.  

PubMed

To investigate the features of electroencephalography (EEG) power and coherence at rest and during a working memory task of patients with mild cognitive impairment (MCI). Thirty-five patients (17 males, 18 females; 52-71 years old) and 34 sex- and age-matched controls (17 males, 17 females; 51-63 years old) were recruited in the present study. Mini-Mental State Examination (MMSE) of 35 patients with MCI and 34 normal controls revealed that the scores of MCI patients did not differ significantly from those of normal controls (P>0.05). Then, EEGs at rest and during working memory task with three levels of working memory load were recorded. The EEG power was computed over 10 channels: right and left frontal (F3, F4), central (C3, C4), parietal (P3, P4), temporal (T5, T6) and occipital (O1, O2); inter-hemispheric coherences were computed from five electrode pairs of F3-F4, C3-C4, P3-P4, T5-T6 and O1-O2 for delta (1.0-3.5 Hz), theta (4.0-7.5 Hz), alpha-1 (8.0-10.0 Hz), alpha-2 (10.5 -13.0 Hz), beta-1 (13.5-18.0 Hz) and beta-2 (18.5-30.0 Hz) frequency bands. All values of the EEG power of MCI patients were found to be higher than those of normal controls at rest and during working memory tasks. Furthermore, the values of EEG power in the theta, alpha-1, alpha-2 and beta-1 bands of patients with MCI were significantly high (P<0.05) in comparison with those of normal controls. Correlation analysis indicated a significant negative correlation between the EEG powers and MMSE scores. In addition, during working memory tasks, the EEG coherences in all bands were significantly higher in the MCI group in comparison with those in the control group (P<0.05). However, there was no significant difference in EEG coherences between two groups at rest. These findings comprise evidence that MCI patients have higher EEG power at rest, and higher EEG power and coherence during working conditions. It suggests that MCI may be associated with compensatory processes at rest and during working memory tasks. Moreover, failure of normal cortical connections may be exist in MCI patients. PMID:16358382

Jiang, Zheng-yan

2005-12-01

98

Expression of the Interleukin-7 Receptor Alpha Chain (CD127) on Virus-Specific CD8+ T Cells Identifies Functionally and Phenotypically Defined Memory T Cells during Acute Resolving Hepatitis B Virus Infection  

PubMed Central

Virus-specific CD8+ T cells play a central role in the outcome of several viral infections, including hepatitis B virus (HBV) infection. A key feature of virus-specific CD8+ T cells is the development of memory. The mechanisms resulting in the establishment of T-cell memory are still only poorly understood. It has been suggested that T-cell memory may depend on the survival of virus-specific CD8+ T cells in the contraction phase. Indeed, a population of effector cells that express high levels of the interleukin-7 receptor alpha chain (CD127) as the precursors of memory CD8+ T cells has recently been identified in mice. However, very little information is currently available about the kinetics of CD127 expression in an acute resolving viral infection in humans and its association with disease pathogenesis, viral load, and functional and phenotypical T-cell characteristics. To address these important issues, we analyzed the HBV-specific CD8+ T-cell response longitudinally in a cohort of six patients with acute HBV infection who spontaneously cleared the virus. We observed the emergence of CD127 expression on antigen-specific CD8+ memory T cells during the course of infection. Importantly, the up-regulation of CD127 correlated phenotypically with a loss of CD38 and PD-1 expression and acquisition of CCR7 expression: functionally with an enhanced proliferative capacity and clinically with the decline in serum alanine aminotransferase levels and viral clearance. These results suggest that the expression of CD127 is a marker for the development of functionally and phenotypically defined antigen-specific CD8+ memory T cells in cleared human viral infections. PMID:16537621

Boettler, Tobias; Panther, Elisabeth; Bengsch, Bertram; Nazarova, Natalja; Spangenberg, Hans Christian; Blum, Hubert E.; Thimme, Robert

2006-01-01

99

Gender differences in association between serotonin transporter gene polymorphism and resting-state EEG activity.  

PubMed

Human brain oscillations represent important features of information processing and are highly heritable. Gender has been observed to affect association between the 5-HTTLPR (serotonin-transporter-linked polymorphic region) polymorphism and various endophenotypes. This study aimed to investigate the effects of 5-HTTLPR on the spontaneous electroencephalography (EEG) activity in healthy male and female subjects. DNA samples extracted from buccal swabs and resting EEG recorded at 60 standard leads were collected from 210 (101 men and 109 women) volunteers. Spectral EEG power estimates and cortical sources of EEG activity were investigated. It was shown that effects of 5-HTTLPR polymorphism on electrical activity of the brain vary as a function of gender. Women with the S/L genotype had greater global EEG power compared to men with the same genotype. In men, current source density was markedly different among genotype groups in only alpha 2 and alpha 3 frequency ranges: S/S allele carriers had higher current source density estimates in the left inferior parietal lobule in comparison with the L/L group. In women, genotype difference in global power asymmetry was found in the central-temporal region. Contrasting L/L and S/L genotype carriers also yielded significant effects in the right hemisphere inferior parietal lobule and the right postcentral gyrus with L/L genotype carriers showing lower current source density estimates than S/L genotype carriers in all but gamma bands. So, in women, the effects of 5-HTTLPR polymorphism were associated with modulation of the EEG activity in a wide range of EEG frequencies. The significance of the results lies in the demonstration of gene by sex interaction with resting EEG that has implications for understanding sex-related differences in affective states, emotion and cognition. PMID:25450956

Volf, N V; Belousova, L V; Knyazev, G G; Kulikov, A V

2015-01-22

100

Multisensory integration of dynamic emotional faces and voices: method for simultaneous EEG-fMRI measurements  

PubMed Central

Combined EEG-fMRI analysis correlates time courses from single electrodes or independent EEG components with the hemodynamic response. Implementing information from only one electrode, however, may miss relevant information from complex electrophysiological networks. Component based analysis, in turn, depends on a priori knowledge of the signal topography. Complex designs such as studies on multisensory integration of emotions investigate subtle differences in distributed networks based on only a few trials per condition. Thus, they require a sensitive and comprehensive approach which does not rely on a-priori knowledge about the underlying neural processes. In this pilot study, feasibility and sensitivity of source localization-driven analysis for EEG-fMRI was tested using a multisensory integration paradigm. Dynamic audiovisual stimuli consisting of emotional talking faces and pseudowords with emotional prosody were rated in a delayed response task. The trials comprised affectively congruent and incongruent displays. In addition to event-locked EEG and fMRI analyses, induced oscillatory EEG responses at estimated cortical sources and in specific temporo-spectral windows were correlated with the corresponding BOLD responses. EEG analysis showed high data quality with less than 10% trial rejection. In an early time window, alpha oscillations were suppressed in bilateral occipital cortices and fMRI analysis confirmed high data quality with reliable activation in auditory, visual and frontal areas to the presentation of multisensory stimuli. In line with previous studies, we obtained reliable correlation patterns for event locked occipital alpha suppression and BOLD signal time course. Our results suggest a valid methodological approach to investigate complex stimuli using the present source localization driven method for EEG-fMRI. This novel procedure may help to investigate combined EEG-fMRI data from novel complex paradigms with high spatial and temporal resolution. PMID:24294195

Schelenz, Patrick D.; Klasen, Martin; Reese, Barbara; Regenbogen, Christina; Wolf, Dhana; Kato, Yutaka; Mathiak, Klaus

2013-01-01

101

Lateralization of interictal EEG findings.  

PubMed

Several reports indicate that interictal epileptiform discharges (IED) may be more likely to occur over the left cerebral hemisphere than over the right. The objective of our study was to determine the frequency and type of IED on routine and multihour EEGs in a tertiary epilepsy center to estimate the frequency of left-sided versus right-sided IED and to determine interictal spike distribution pattern differences between adult and pediatric epilepsy patients. The current study retrospectively reviewed 31,207 EEGs (25,793 routine EEGs and 5414 multihour EEGs) recorded on 24,003 patients during the period from 1993 to 2003. All EEGs were read according to a systematic EEG classification system. Every patient was considered only once by including the first abnormal EEG. Regional unilateral or bilateral IEDs were recorded in 1707 patients (7%). Regional unilateral or bilateral slow was recorded in 2297 patients (9.6%). Left-sided regional IED were seen in 828 patients and accounted for 58% of all unilateral IED. Left-sided slow was seen in 1389 patients and accounted for 65% of all unilateral slow. Lateralization of slow was due to intermittent slow, whereas continuous slow involved both hemispheres equally. There was no lateralization difference in benign focal epileptiform discharges of childhood. Lateralization shows a tendency toward greater left-sided lateralization of interictal findings with aging. Benign focal epileptiform discharges were only seen under the age of 20 years old. Regional IEDs were seen in approximately 7% of patients and slowing occurs in 10% of patients. Both abnormalities were seen more frequently in the left hemisphere. Age adjusted analysis of the data revealed that this left-sided predominance was mildly increased in adults as compared with pediatric patients. PMID:17912060

Loddenkemper, Tobias; Burgess, Richard C; Syed, Tanvir; Pestana, Elia M

2007-10-01

102

Sensitivity of scalp eeg, cortical eeg, and somatosensory evoked responses during surgery for intracranial aneurysms  

Microsoft Academic Search

BACKGROUNDWe estimated the relative sensitivity and reliability of scalp EEG, cortical EEG and somatosensory evoked potentials (SSEPs) to detect significant changes during aneurysm surgery.METHODSTwo observers independently reviewed data from 18 patients who were monitored with scalp EEG, cortical EEG, and SSEPs to determine which if any modality demonstrated significant changes during 25 different episodes of temporary intracranial vascular occlusion.RESULTSKappa scores

Christopher J Martin; Grant Sinson; Terry Patterson; Eric L Zager; Mark M Stecker

2002-01-01

103

Autonomic and EEG Patterns during Eyes-Closed Rest and Transcendental Meditation (TM) Practice: The Basis for a Neural Model of TM Practice  

Microsoft Academic Search

In this single-blind within-subject study, autonomic and EEG variables were compared during 10-min, order-balanced eyes-closed rest and Transcendental Meditation (TM) sessions. TM sessions were distinguished by (1) lower breath rates, (2) lower skin conductance levels, (3) higher respiratory sinus arrhythmia levels, and (4) higher alpha anterior–posterior and frontal EEG coherence. Alpha power was not significantly different between conditions. These results

Frederick Travis; R. Keith Wallace

1999-01-01

104

Alpha asymmetry in infants at risk for autism spectrum disorders.  

PubMed

An emerging focus of research on autism spectrum disorder (ASD) targets the identification of early-developing ASD endophenotypes using infant siblings of affected children. One potential neural endophenotype is resting frontal electroencephalogram (EEG) alpha asymmetry, a metric of hemispheric organization. Here, we examined the development of frontal EEG alpha asymmetry in ASD high-risk and low-risk infant populations. Our findings demonstrate that low and high-risk infants show different patterns of alpha asymmetry at 6 months of age and opposite growth trajectories in asymmetry over the following 12 months. These results support the candidacy of alpha asymmetry as an early neural ASD endophenotype. PMID:23989937

Gabard-Durnam, Laurel; Tierney, Adrienne L; Vogel-Farley, Vanessa; Tager-Flusberg, Helen; Nelson, Charles A

2015-02-01

105

Motion-related artefacts in EEG predict neuronally plausible patterns of activation in fMRI data.  

PubMed

The simultaneous acquisition and subsequent analysis of EEG and fMRI data is challenging owing to increased noise levels in the EEG data. A common method to integrate data from these two modalities is to use aspects of the EEG data, such as the amplitudes of event-related potentials (ERP) or oscillatory EEG activity, to predict fluctuations in the fMRI data. However, this relies on the acquisition of high quality datasets to ensure that only the correlates of neuronal activity are being studied. In this study, we investigate the effects of head-motion-related artefacts in the EEG signal on the predicted T2*-weighted signal variation. We apply our analyses to two independent datasets: 1) four participants were asked to move their feet in the scanner to generate small head movements, and 2) four participants performed an episodic memory task. We created T2*-weighted signal predictors from indicators of abrupt head motion using derivatives of the realignment parameters, from visually detected artefacts in the EEG as well as from three EEG frequency bands (theta, alpha and beta). In both datasets, we found little correlation between the T2*-weighted signal and EEG predictors that were not convolved with the canonical haemodynamic response function (cHRF). However, all convolved EEG predictors strongly correlated with the T2*-weighted signal variation in various regions including the bilateral superior temporal cortex, supplementary motor area, medial parietal cortex and cerebellum. The finding that movement onset spikes in the EEG predict T2*-weighted signal intensity only when the time course of movements is convolved with the cHRF, suggests that the correlated signal might reflect a BOLD response to neural activity associated with head movement. Furthermore, the observation that broad-spectral EEG spikes tend to occur at the same time as abrupt head movements, together with the finding that abrupt movements and EEG spikes show similar correlations with the T2*-weighted signal, indicates that the EEG spikes are produced by abrupt movement and that continuous regressors of EEG oscillations contain motion-related noise even after stringent correction of the EEG data. If not properly removed, these artefacts complicate the use of EEG data as a predictor of T2*-weighted signal variation. PMID:21763774

Jansen, Marije; White, Thomas P; Mullinger, Karen J; Liddle, Elizabeth B; Gowland, Penny A; Francis, Susan T; Bowtell, Richard; Liddle, Peter F

2012-01-01

106

The alpha-galactosidase A p.Arg118Cys variant does not cause a Fabry disease phenotype: Data from individual patients and family studies.  

PubMed

Lysosomal ?-galactosidase A (?-Gal) is the enzyme deficient in Fabry disease (FD), an X-linked glycosphingolipidosis caused by pathogenic mutations affecting the GLA gene. The early-onset, multi-systemic FD classical phenotype is associated with absent or severe enzyme deficiency, as measured by in vitro assays, but patients with higher levels of residual ?-Gal activity may have later-onset, more organ-restricted clinical presentations. A change in the codon 118 of the wild-type ?-Gal sequence, replacing basic arginine by a potentially sulfhydryl-binding cysteine residue - GLA p.(Arg118Cys) -, has been recurrently described in large FD screening studies of high-risk patients. Although the Cys118 allele is associated with high residual ?-Gal activity in vitro, it has been classified as a pathogenic mutation, mainly on the basis of theoretical arguments about the chemistry of the cysteine residue. However its pathogenicity has never been convincingly demonstrated by pathology criteria. We reviewed the clinical, biochemical and histopathology data obtained from 22 individuals of Portuguese and Spanish ancestry carrying the Cys118 allele, including 3 homozygous females. Cases were identified either on the differential diagnosis of possible FD manifestations and on case-finding studies (n=11; 4 males), or on unbiased cascade screening of probands' close relatives (n=11; 3 males). Overall, those data strongly suggest that the GLA p.(Arg118Cys) variant does not segregate with FD clinical phenotypes in a Mendelian fashion, but might be a modulator of the multifactorial risk of cerebrovascular disease. The Cys118 allelic frequency in healthy Portuguese adults (n=696) has been estimated as 0.001, therefore not qualifying for "rare" condition. PMID:25468652

Ferreira, Susana; Ortiz, Alberto; Germain, Dominique P; Viana-Baptista, Miguel; Caldeira-Gomes, António; Camprecios, Marta; Fenollar-Cortés, Maria; Gallegos-Villalobos, Ángel; Garcia, Diego; García-Robles, José Antonio; Egido, Jesús; Gutiérrez-Rivas, Eduardo; Herrero, José Antonio; Mas, Sebastián; Oancea, Raluca; Péres, Paloma; Salazar-Martín, Luis Manuel; Solera-Garcia, Jesús; Alves, Helena; Garman, Scott C; Oliveira, João Paulo

2015-02-01

107

Levels of alpha-toxin correlate with distinct phenotypic response profiles of blood mononuclear cells and with agr background of community-associated Staphylococcus aureus isolates.  

PubMed

Epidemiological studies of Staphylococcus aureus have shown a relation between certain clones and the presence of specific virulence genes, but how this translates into virulence-associated functional responses is not fully elucidated. Here we addressed this issue by analyses of community-acquired S. aureus strains characterized with respect to antibiotic resistance, ST types, agr types, and virulence gene profiles. Supernatants containing exotoxins were prepared from overnight bacterial cultures, and tested in proliferation assays using human peripheral blood mononuclear cells (PBMC). The strains displayed stable phenotypic response profiles, defined by either a proliferative or cytotoxic response. Although, virtually all strains elicited superantigen-mediated proliferative responses, the strains with a cytotoxic profile induced proliferation only in cultures with the most diluted supernatants. This indicated that the superantigen-response was masked by a cytotoxic effect which was also confirmed by flow cytometry analysis. The cytotoxic supernatants contained significantly higher levels of ?-toxin than did the proliferative supernatants. Addition of ?-toxin to supernatants characterized as proliferative switched the response into cytotoxic profiles. In contrast, no effect of Panton Valentine Leukocidin, ?-toxin or phenol soluble modulin ?-3 was noted in the proliferative assay. Furthermore, a significant association between agr type and phenotypic profile was found, where agrII and agrIII strains had predominantly a proliferative profile whereas agrI and IV strains had a predominantly cytotoxic profile. The differential response profiles associated with specific S. aureus strains with varying toxin production could possibly have an impact on disease manifestations, and as such may reflect specific pathotypes. PMID:25166615

Mairpady Shambat, Srikanth; Haggar, Axana; Vandenesch, Francois; Lina, Gerard; van Wamel, Willem J B; Arakere, Gayathri; Svensson, Mattias; Norrby-Teglund, Anna

2014-01-01

108

EEG mapping investigations of psychomotor and music perception brain dysfunction in untreated schizophrenic patients.  

PubMed

Twenty-six untreated schizophrenic inpatients and 34 control persons were investigated using 16-channel EEG mapping during resting, manumotor and music perception tasks. Power values of activation tasks were each referenced to a separate, immediately preceding resting condition, using conventional delta, theta, alpha and 2 beta frequency bands. Results in delta and alpha bands, which maximally separated the two groups, are reported only for space reasons. Results indicated a "nonreactivity" (in all frequency bands) on the two activation paradigms in schizophrenic patients as a group. Major gender effects were obtained in normal persons, but not signs of nonreactivity comparable to patients. Subdividing patients exclusively by means of their EEG changes on activation produced meaningful clinical subgroups of "positive/negative" schizophrenics. This latter finding could contribute towards clinical utility of EEG mapping in psychiatry. PMID:8127321

Günther, W; Klages, U; Mayr, M; Haag, C; Müller, N; Hantschk, I; Streck, P; Steinberg, R; Baghai, T; Banquet, J P

1993-12-01

109

Neural basis of postural instability identified by VTC and EEG.  

PubMed

In this study, we investigated the neural basis of virtual time to contact (VTC) and the hypothesis that VTC provides predictive information for future postural instability. A novel approach to differentiate stable pre-falling and transition-to-instability stages within a single postural trial while a subject was performing a challenging single leg stance with eyes closed was developed. Specifically, we utilized wavelet transform and stage segmentation algorithms using VTC time series data set as an input. The VTC time series was time-locked with multichannel (n = 64) EEG signals to examine its underlying neural substrates. To identify the focal sources of neural substrates of VTC, a two-step approach was designed combining the independent component analysis (ICA) and low-resolution tomography (LORETA) of multichannel EEG. There were two major findings: (1) a significant increase of VTC minimal values (along with enhanced variability of VTC) was observed during the transition-to-instability stage with progression to ultimate loss of balance and falling; and (2) this VTC dynamics was associated with pronounced modulation of EEG predominantly within theta, alpha and gamma frequency bands. The sources of this EEG modulation were identified at the cingulate cortex (ACC) and the junction of precuneus and parietal lobe, as well as at the occipital cortex. The findings support the hypothesis that the systematic increase of minimal values of VTC concomitant with modulation of EEG signals at the frontal-central and parietal-occipital areas serve collectively to predict the future instability in posture. PMID:19655130

Slobounov, Semyon; Cao, Cheng; Jaiswal, Niharika; Newell, Karl M

2009-10-01

110

Neural basis of postural instability identified by VTC and EEG  

PubMed Central

In this study, we investigated the neural basis of virtual time to contact (VTC) and the hypothesis that VTC provides predictive information for future postural instability. A novel approach to differentiate stable pre-falling and transition-to-instability stages within a single postural trial while a subject was performing a challenging single leg stance with eyes closed was developed. Specifically, we utilized wavelet transform and stage segmentation algorithms using VTC time series data set as an input. The VTC time series was time-locked with multichannel (n = 64) EEG signals to examine its underlying neural substrates. To identify the focal sources of neural substrates of VTC, a two-step approach was designed combining the independent component analysis (ICA) and low-resolution tomography (LORETA) of multichannel EEG. There were two major findings: (1) a significant increase of VTC minimal values (along with enhanced variability of VTC) was observed during the transition-to-instability stage with progression to ultimate loss of balance and falling; and (2) this VTC dynamics was associated with pronounced modulation of EEG predominantly within theta, alpha and gamma frequency bands. The sources of this EEG modulation were identified at the cingulate cortex (ACC) and the junction of precuneus and parietal lobe, as well as at the occipital cortex. The findings support the hypothesis that the systematic increase of minimal values of VTC concomitant with modulation of EEG signals at the frontal-central and parietal–occipital areas serve collectively to predict the future instability in posture. PMID:19655130

Cao, Cheng; Jaiswal, Niharika; Newell, Karl M.

2010-01-01

111

Effects of a Psychedelic, Tropical Tea, Ayahuasca, on the Electroencephalographic (EEG) Activity of the Human Brain During a Shamanistic Ritual  

Microsoft Academic Search

EEG data from 12 volunteers participating in a workshop in Brazil were recorded under field conditions before and after a shamanistic ritual in which the psychoactive tea, ayahuasca, was consumed. Following three doses of the tea, the subjects showed strong and statistically significant increases of both EEG alpha (8-13Hz) and theta (4-8Hz) mean amplitudes compared to baseline while beta (13-20Hz)

Jan M. Keppel Hesselink; M. da Silveira Barbosa

2001-01-01

112

Quantitative EEG analysis at rest and during photic stimulation in drug-naive patients with first-episode paranoid schizophrenia  

Microsoft Academic Search

In the present study, quantitative EEG analysis was performed at rest and during 10 Hz photic stimulation in 14 drug-naive patients with first-episode paranoid schizophrenia and 20 sex- and age-matched control subjects. Compared with the normal controls, the patients had significantly lower alpha-2 band amplitude in the resting EEG over all recording regions. No significant group differences were found in

Yuji Wada; Yuko Takizawa; Saeko Kitazawa; Jiang Zheng-Yan; Nariyoshi Yamaguchi

1994-01-01

113

Cortical atrophy in Alzheimer's disease unmasks electrically silent sulci and lowers EEG dipolarity  

Microsoft Academic Search

Alzheimer's disease (AD) patients show lower dipolarity (goodness-of-fit) for dipole localizations of alpha or other dominant electroencephalography (EEG) frequency components in the occipital cortex. In the present study, we performed computer simulations to discover which of distributions of dipole activity lower dipolarity in a manner similar to that seen in severe AD. Dipolarity was estimated from simulations of various electric

Junko Hara; William Rodman Shankle; Toshimitsu Musha

1999-01-01

114

Neural Activations during Visual Sequence Learning Leave a Trace in Post-Training Spontaneous EEG  

PubMed Central

Recent EEG studies have shown that implicit learning involving specific cortical circuits results in an enduring local trace manifested as local changes in spectral power. Here we used a well characterized visual sequence learning task and high density-(hd-)EEG recording to determine whether also declarative learning leaves a post-task, local change in the resting state oscillatory activity in the areas involved in the learning process. Thus, we recorded hd-EEG in normal subjects before, during and after the acquisition of the order of a fixed spatial target sequence (VSEQ) and during the presentation of targets in random order (VRAN). We first determined the temporal evolution of spectral changes during VSEQ and compared it to VRAN. We found significant differences in the alpha and theta bands in three main scalp regions, a right occipito-parietal (ROP), an anterior-frontal (AFr), and a right frontal (RFr) area. The changes in frontal theta power during VSEQ were positively correlated with the learning rate. Further, post-learning EEG recordings during resting state revealed a significant increase in alpha power in ROP relative to a pre-learning baseline. We conclude that declarative learning is associated with alpha and theta changes in frontal and posterior regions that occur during the task, and with an increase of alpha power in the occipito-parietal region after the task. These post-task changes may represent a trace of learning and a hallmark of use-dependent plasticity. PMID:23799058

Moisello, Clara; Meziane, Hadj Boumediene; Kelly, Simon; Perfetti, Bernardo; Kvint, Svetlana; Voutsinas, Nicholas; Blanco, Daniella; Quartarone, Angelo; Tononi, Giulio; Ghilardi, Maria Felice

2013-01-01

115

Lateralization of Auditory Language: An EEG Study of Bilingual Crow Indian Adolescents.  

ERIC Educational Resources Information Center

A study was undertaken to learn whether involvement of the brain's right hemisphere in auditory language processing, a phenomenon found in a previous study of Crow-English bilinguals, was language-specific. Alpha blocking response as measured by electroencephalography (EEG) was used as an indicator of brain activity. It was predicted that (1)…

Vocate, Donna R.

116

The EEG as an index of neuromodulator balance in memory and mental illness  

PubMed Central

There is a strong correlation between signature EEG frequency patterns and the relative levels of distinct neuromodulators. These associations become particularly evident during the sleep-wake cycle. The monoamine-acetylcholine balance hypothesis is a theory of neurophysiological markers of the EEG and a detailed description of the findings that support this proposal are presented in this paper. According to this model alpha rhythm reflects the relative predominance of cholinergic muscarinic signals and delta rhythm that of monoaminergic receptor effects. Both high voltage synchronized rhythms are likely mediated by inhibitory G?i/o-mediated transduction of inhibitory interneurons. Cognitively, alpha and delta EEG measures are proposed to indicate automatic and flexible strategies, respectively. Sleep is associated with marked changes in relative neuromodulator levels corresponding to EEG markers of distinct stages. Sleep studies on memory consolidation present some of the strongest evidence yet for the respective roles of monoaminergic and cholinergic projections in declarative and non-declarative memory processes, a key theoretical premise for understanding the data. Affective dysregulation is reflected in altered EEG patterns during sleep. PMID:24782698

Vakalopoulos, Costa

2014-01-01

117

Use of EEG to track visual attention in two dimensions  

NASA Astrophysics Data System (ADS)

This thesis investigates the use of EEG to track the spatial locus of covert, visual attention. Three experiments are described that were to detect the position of visual attention as it was deployed towards targets as they appeared. The first experiment uses flickering fields placed in the periphery of the visual field to induce SSVEPs, to be used to track the position of attention which varies horizontally between them. The flickers failed to produce significant SSVEP activity. However attention locus could still able to be tracked by endogenous lateralizations of 12Hz and 18Hz activity. A second experiment was then designed to track attention locus as it varied either horizontally or vertically using only endogenous EEG activity in the alpha (10Hz), low-beta (18Hz), high-beta (24Hz) and gamma (36Hz) bands. Tracking proved successful in all but a small number of subjects. Horizontally varying attention was associated with lateralizations of the alpha band and low-beta band, while vertically varying attention was associated with varying alpha band and low-beta band activity in the occipito-parietal junction over the central sulcus. A third experiment was then performed to track attention locus as it varied in two dimensions. Using a combination of the features found to be informative in the second experiment, tracking proved successful in up to nine bins of two-dimensional visual space. Tracking in either the horizontal or vertical dimension was also successful when attention varied in two dimensions. The success of this method shows that EEG can be used to passively detect the spatial position of attention, at varying degrees of position, as a person attends to objects they see.

Coleman, Robert Alan

118

Apolipoprotein E ?4 allele decreases functional connectivity in Alzheimer's disease as measured by EEG coherence  

PubMed Central

OBJECTIVES—The ?4 allele of apolipoprotein E (APOE) represents a major biological risk factor for late onset Alzheimer's disease. However, it is still not known whether the APOE genotype affects the progression of the disease, assessed by different functional methods.?METHODS—The study sample included 41 patients with probable Alzheimer's disease. Subjects had similar severity of disease, age of onset, and duration of illness, and were subcategorised according to their APOE genotypes: 17 with no ?4 allele, 14 with one ?4 allele, and 10 with two ?4 alleles. The control group consisted of 18 healthy subjects comparable with the patients in age and education. Analysed quantitive EEG (qEEG) variables were the ratio of alpha and theta absolute power and EEG coherence in alpha frequency band, representing major cortical association pathways.?RESULTS—There was pronounced EEG slowing in all three patient subgroups compared with the controls for the alpha/theta ratio, but there was no significant difference across the patient subgroups. Patients homozygous for the APOE ?4 allele had reduced right and left temporoparietal, right temporofrontal, and left occipitoparietal coherence. Patients without and with one ?4 allele showed an overlap between the control group and group with two ?4 alleles in coherence measures.?CONCLUSIONS—APOE ?4 does not influence EEG slowing, an index which reflects severity of the disease in patients with Alzheimer's disease, but seems to be associated with selective decreases in functional connectivity as assessed by EEG coherence. This finding might be of clinical importance when considering different pathogenetic mechanisms.?? PMID:9221969

Jelic, V.; Julin, P.; Shigeta, M.; Nordberg, A.; Lannfelt, L.; Winblad, B.; Wahlund, L.

1997-01-01

119

Childhood abuse and EEG source localization in crack cocaine dependence.  

PubMed

Fourteen subjects with histories of sexual and/or physical abuse in childhood and 13 matched control subjects were selected from a consecutive series of clients in residential treatment for crack cocaine dependence. Standardized low-resolution electromagnetic brain tomography (sLORETA) was used to estimate the source generators of the EEG in a cortical mask with voxel z-scores referenced to normative data at frequency intervals of 039 Hz, with nonparametric permutation to correct by randomization for the number of comparisons and the intercorrelations and variance of distribution of voxel values. Subjects with histories of abuse in childhood had significantly greater EEG power than controls in the theta frequency range (3.51-7.41 Hz), with greatest differences in the 3.90-Hz band distributed mainly in the parahippocampal, fusiform, lingual, posterior cingulate, and insular gyri. The groups did not differ significantly with regard to delta (1.56-3.12 Hz), alpha (7.81-12.48 Hz), beta (12.87-19.89 Hz), and gamma (20.28-35.10 Hz) frequency power. In excess, theta EEG power, a bandwidth of transactions among hippocampus and amygdala and paralimbic and visual association cortex, may be a correlate of childhood exposure to abuse. PMID:23693089

Alper, Kenneth; Shah, Jaini; Howard, Bryant; Roy John, E; Prichep, Leslie S

2013-07-30

120

[Gender differences in resting EEG related to Eysenk's Personality Traits].  

PubMed

EEG mapping was used to study gender differences in hemispheric organization related to personality (40 male and 42 female subjects, the students 17-20 ages). The results showed, that each clearly defined personality trait (neuroticism, extraversion, psychoticizm and social conformity) characterized by special EEG pattern differenced on men and women groups. At the same time, more close interaction of gender and neuroticism was observed, but gender and extraversion were less connected. Neuroticism related patterns of coherence in the alpha2- and beta2-bands were associated with an activity changes in anterior cortex in men but posterior--in women, at that the positive correlations were observed in the beta2-band in the former case and negative ones in the second. There are two opposing tendencies of the interaction between extraversion and gender in a modulation of the resting theta-rhythm: an increase of cortex connections in men and decrease ones in women. The specificity of spatial-temporal EEG patterns in men associated mostly with a psychoticizm value but in women--with a social conformism. In either case these personality traits related to activity of frontal cortex in the left hemisphere. PMID:15481382

Razumnikova, O M

2004-01-01

121

Subtractive fuzzy classifier based driver distraction levels classification using EEG.  

PubMed

[Purpose] In earlier studies of driver distraction, researchers classified distraction into two levels (not distracted, and distracted). This study classified four levels of distraction (neutral, low, medium, high). [Subjects and Methods] Fifty Asian subjects (n=50, 43 males, 7 females), age range 20-35 years, who were free from any disease, participated in this study. Wireless EEG signals were recorded by 14 electrodes during four types of distraction stimuli (Global Position Systems (GPS), music player, short message service (SMS), and mental tasks). We derived the amplitude spectrum of three different frequency bands, theta, alpha, and beta of EEG. Then, based on fusion of discrete wavelet packet transforms and fast fourier transform yield, we extracted two features (power spectral density, spectral centroid frequency) of different wavelets (db4, db8, sym8, and coif5). Mean ± SD was calculated and analysis of variance (ANOVA) was performed. A fuzzy inference system classifier was applied to different wavelets using the two extracted features. [Results] The results indicate that the two features of sym8 posses highly significant discrimination across the four levels of distraction, and the best average accuracy achieved by the subtractive fuzzy classifier was 79.21% using the power spectral density feature extracted using the sym8 wavelet. [Conclusion] These findings suggest that EEG signals can be used to monitor distraction level intensity in order to alert drivers to high levels of distraction. PMID:24259914

Wali, Mousa Kadhim; Murugappan, Murugappan; Ahmad, Badlishah

2013-09-01

122

EEG-microstate dependent emergence of perceptual awareness  

PubMed Central

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 targets that were correctly identified 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. PMID:24860450

Britz, Juliane; Díaz Hernàndez, Laura; Ro, Tony; Michel, Christoph M.

2014-01-01

123

Sleep misperception, EEG characteristics and autonomic nervous system activity in primary insomnia: a retrospective study on polysomnographic data.  

PubMed

Misperception of Sleep Onset Latency, often found in Primary Insomnia, has been cited to be influenced by hyperarousal, reflected in EEG- and ECG-related indices. The aim of this retrospective study was to examine the association between Central Nervous System (i.e. EEG) and Autonomic Nervous System activity in the Sleep Onset Period and the first NREM sleep cycle in Primary Insomnia (n=17) and healthy controls (n=11). Furthermore, the study examined the influence of elevated EEG and Autonomic Nervous System activity on Stage2 sleep-protective mechanisms (K-complexes and sleep spindles). Confirming previous findings, the Primary Insomnia-group overestimated Sleep Onset Latency and this overestimation was correlated with elevated EEG activity. A higher amount of beta EEG activity during the Sleep Onset Period was correlated with the appearance of K-complexes immediately followed by a sleep spindle in the Primary Insomnia-group. This can be interpreted as an extra attempt to protect sleep continuity or as a failure of the sleep-protective role of the K-complex by fast EEG frequencies following within one second. The strong association found between K-alpha (K-complex within one second followed by 8-12 Hz EEG activity) in Stage2 sleep and a lower parasympathetic Autonomic Nervous System dominance (less high frequency HR) in Slow-wave sleep, further assumes a state of hyperarousal continuing through sleep in Primary Insomnia. PMID:24177246

Maes, J; Verbraecken, J; Willemen, M; De Volder, I; van Gastel, A; Michiels, N; Verbeek, I; Vandekerckhove, M; Wuyts, J; Haex, B; Willemen, T; Exadaktylos, V; Bulckaert, A; Cluydts, R

2014-03-01

124

On the Individuality of Sleep EEG Spectra  

PubMed Central

Research in recent years has supported the hypothesis that many properties of the electroencephalogram (EEG) are specific to an individual. In this study, the intra- and inter-individual variations of sleep EEG signals were investigated. This was carried out by analyzing the stability of the average EEG spectra individually computed for the Rechtschaffen and Kales (RK) sleep stages. Six EEG channels were used to account for the topographical aspect of the analysis. Validity of the results was supported by considering a wide dataset of 174 subjects with normal sleep. Subjects spent two consecutive nights in the sleep laboratory during which EEG recordings were obtained. High similarity between average spectra of two consecutive nights was found considering an individual. More than 89% of the second night recordings were correctly assigned to their counterparts of the first night. The average spectra of sleep EEG computed for each RK sleep stage have shown a high degree of individuality. PMID:23997385

Lewandowski, Achim; Rosipal, Roman; Dorffner, Georg

2013-01-01

125

EEG Data Driven Animation and Its Application  

Microsoft Academic Search

Human electroencephalograph (EEG) data driven animation is often used in neurofeedback systems for concentration training\\u000a in children and adults. Visualization of the time-series data could be used in neurofeedback and for the data analysis. The\\u000a paper proposes a novel method of 3D mapping of EEG data and describes visualization system VisBrain that was developed for\\u000a EEG data analysis. We employed

Olga Sourina; Alexei Sourin; Vladimir Kulish

2009-01-01

126

Full-band EEG (FbEEG): an emerging standard in electroencephalography  

Microsoft Academic Search

While enormous resources have been recently invested into the development of a variety of neuroimaging techniques, the bandwidth of the clinical EEG, originally set by trivial technical limitations, has remained practically unaltered for over 50 years. An increasing amount of evidence shows that salient EEG signals are observed beyond the bandwidth of the routine clinical EEG, which is typically around

Sampsa Vanhatalo; Juha Voipio; Kai Kaila

2005-01-01

127

From Oscillatory Transcranial Current Stimulation to Scalp EEG Changes: A Biophysical and Physiological Modeling Study  

PubMed Central

Both biophysical and neurophysiological aspects need to be considered to assess the impact of electric fields induced by transcranial current stimulation (tCS) on the cerebral cortex and the subsequent effects occurring on scalp EEG. The objective of this work was to elaborate a global model allowing for the simulation of scalp EEG signals under tCS. In our integrated modeling approach, realistic meshes of the head tissues and of the stimulation electrodes were first built to map the generated electric field distribution on the cortical surface. Secondly, source activities at various cortical macro-regions were generated by means of a computational model of neuronal populations. The model parameters were adjusted so that populations generated an oscillating activity around 10 Hz resembling typical EEG alpha activity. In order to account for tCS effects and following current biophysical models, the calculated component of the electric field normal to the cortex was used to locally influence the activity of neuronal populations. Lastly, EEG under both spontaneous and tACS-stimulated (transcranial sinunoidal tCS from 4 to 16 Hz) brain activity was simulated at the level of scalp electrodes by solving the forward problem in the aforementioned realistic head model. Under the 10 Hz-tACS condition, a significant increase in alpha power occurred in simulated scalp EEG signals as compared to the no-stimulation condition. This increase involved most channels bilaterally, was more pronounced on posterior electrodes and was only significant for tACS frequencies from 8 to 12 Hz. The immediate effects of tACS in the model agreed with the post-tACS results previously reported in real subjects. Moreover, additional information was also brought by the model at other electrode positions or stimulation frequency. This suggests that our modeling approach can be used to compare, interpret and predict changes occurring on EEG with respect to parameters used in specific stimulation configurations. PMID:23468970

Merlet, Isabelle; Birot, Gwénaël; Salvador, Ricardo; Molaee-Ardekani, Behnam; Mekonnen, Abeye; Soria-Frish, Aureli; Ruffini, Giulio; Miranda, Pedro C.; Wendling, Fabrice

2013-01-01

128

Alpha Thalassemia  

MedlinePLUS

Alpha Thalassemia ? Physicians often mistake alpha thalassemia trait for iron deficiency anemia and incorrectly prescribe iron supplements that have no effect on the anemia. Normal alpha globin genes ...

129

Technical and clinical analysis of microEEG: a miniature wireless EEG device designed to record high-quality EEG in the emergency department  

PubMed Central

Background We describe and characterize the performance of microEEG compared to that of a commercially available and widely used clinical EEG machine. microEEG is a portable, battery-operated, wireless EEG device, developed by Bio-Signal Group to overcome the obstacles to routine use of EEG in emergency departments (EDs). Methods The microEEG was used to obtain EEGs from healthy volunteers in the EEG laboratory and ED. The standard system was used to obtain EEGs from healthy volunteers in the EEG laboratory, and studies recorded from patients in the ED or ICU were also used for comparison. In one experiment, a signal splitter was used to record simultaneous microEEG and standard EEG from the same electrodes. Results EEG signal analysis techniques indicated good agreement between microEEG and the standard system in 66 EEGs recorded in the EEG laboratory and the ED. In the simultaneous recording the microEEG and standard system signals differed only in a smaller amount of 60 Hz noise in the microEEG signal. In a blinded review by a board-certified clinical neurophysiologist, differences in technical quality or interpretability were insignificant between standard recordings in the EEG laboratory and microEEG recordings from standard or electrode cap electrodes in the ED or EEG laboratory. The microEEG data recording characteristics such as analog-to-digital conversion resolution (16 bits), input impedance (>100M?), and common-mode rejection ratio (85 dB) are similar to those of commercially available systems, although the microEEG is many times smaller (88 g and 9.4?×?4.4?×?3.8 cm). Conclusions Our results suggest that the technical qualities of microEEG are non-inferior to a standard commercially available EEG recording device. EEG in the ED is an unmet medical need due to space and time constraints, high levels of ambient electrical noise, and the cost of 24/7 EEG technologist availability. This study suggests that using microEEG with an electrode cap that can be applied easily and quickly can surmount these obstacles without compromising technical quality. PMID:23006616

2012-01-01

130

Increase trend of correlation and phase synchrony of microwire iEEG before macroseizure onset.  

PubMed

Micro/macrowire intracranial EEG (iEEG) signals recorded from implanted micro/macroelectrodes in epileptic patients have received great attention and are considered to include much information of neuron activities in seizure transition compared to scalp EEG from cortical electrodes. Microelectrode is contacted more close to neurons than macroelectrode and it is more sensitive to neuron activity changes than macroelectrode. Microwire iEEG recordings are inevitably advantageous over macrowire iEEG recordings to reveal neuronal mechanisms contributing to the generation of seizures. In this study, we investigate the seizure generation from microwire iEEG recordings and discuss synchronization of microwire iEEGs in four frequency bands: alpha (1-30 Hz), gamma (30-80 Hz), ripple (80-250 Hz), and fast ripple (>250 Hz) via two measures: correlation and phase synchrony. We find that an increase trend of correlation or phase synchrony exists before the macroseizure onset mostly in gamma and ripple bands where the duration of the preictal states varied in different seizures ranging up to a few seconds (minutes). This finding is contrast to the well-known result that a decrease of synchronization in macro domains exists before the macroseizure onset. The finding demonstrates that it is only when the seizure has recruited enough surrounding brain tissue does the signal become strong enough to be observed on the clinical macroelectrode and as a result support the hypothesis of progressive coalescence of microseizure domains. The potential ramifications of such an early detection of microscale seizure activity may open a new window on treatment by making possible disruption of seizure activity before it becomes fully established. PMID:24624231

Hu, Sanqing; Chi, Jianfen; Zhang, Jianhai; Kong, Wanzeng; Cao, Yu; He, Bin

2014-04-01

131

A comparison of continuous video-EEG monitoring and 30-minute EEG in an ICU.  

PubMed

Aim. To determine whether there is added benefit in detecting electrographic abnormalities from 16-24 hours of continuous video-EEG in adult medical/surgical ICU patients, compared to a 30-minute EEG. Methods. This was a prospectively enroled non-randomized study of 130 consecutive ICU patients for whom EEG was requested. For 117 patients, a 30-minute EEG was requested for altered mental state and/or suspected seizures; 83 patients continued with continuous video-EEG for 16-24 hours and 34 patients had only the 30-minute EEG. For 13 patients with prior seizures, continuous video-EEG was requested and was carried out for 16-24 hours. We gathered EEG data prospectively, and reviewed the medical records retrospectively to assess the impact of continuous video-EEG. Results. A total of 83 continuous video-EEG recordings were performed for 16-24 hours beyond 30 minutes of routine EEG. All were slow, and 34% showed epileptiform findings in the first 30 minutes, including 2% with seizures. Over 16-24 hours, 14% developed new or additional epileptiform abnormalities, including 6% with seizures. In 8%, treatment was changed based on continuous video-EEG. Among the 34 EEGs limited to 30 minutes, almost all were slow and 18% showed epileptiform activity, including 3% with seizures. Among the 13 patients with known seizures, continuous video-EEG was slow in all and 69% had epileptiform abnormalities in the first 30 minutes, including 31% with seizures. An additional 8% developed epileptiform abnormalities over 16-24 hours. In 46%, treatment was changed based on continuous video-EEG. Conclusion. This study indicates that if continuous video-EEG is not available, a 30-minute EEG in the ICU has a substantial diagnostic yield and will lead to the detection of the majority of epileptiform abnormalities. In a small percentage of patients, continuous video-EEG will lead to the detection of additional epileptiform abnormalities. In a sub-population, with a history of seizures prior to the initiation of EEG recording, the benefits of continuous video-EEG in monitoring seizure activity and influencing treatment may be greater. PMID:25498516

Khan, Omar I; Azevedo, Christina J; Hartshorn, Alendia L; Montanye, Justin T; Gonzalez, Juan C; Natola, Mark A; Surgenor, Stephen D; Morse, Richard P; Nordgren, Richard E; Bujarski, Krzysztof A; Holmes, Gregory L; Jobst, Barbara C; Scott, Rod C; Thadani, Vijay M

2014-12-01

132

Preterm EEG: a multimodal neurophysiological protocol.  

PubMed

Since its introduction in early 1950s, electroencephalography (EEG) has been widely used in the neonatal intensive care units (NICU) for assessment and monitoring of brain function in preterm and term babies. Most common indications are the diagnosis of epileptic seizures, assessment of brain maturity, and recovery from hypoxic-ischemic events. EEG recording techniques and the understanding of neonatal EEG signals have dramatically improved, but these advances have been slow to penetrate through the clinical traditions. The aim of this presentation is to bring theory and practice of advanced EEG recording available for neonatal units. In the theoretical part, we will present animations to illustrate how a preterm brain gives rise to spontaneous and evoked EEG activities, both of which are unique to this developmental phase, as well as crucial for a proper brain maturation. Recent animal work has shown that the structural brain development is clearly reflected in early EEG activity. Most important structures in this regard are the growing long range connections and the transient cortical structure, subplate. Sensory stimuli in a preterm baby will generate responses that are seen at a single trial level, and they have underpinnings in the subplate-cortex interaction. This brings neonatal EEG readily into a multimodal study, where EEG is not only recording cortical function, but it also tests subplate function via different sensory modalities. Finally, introduction of clinically suitable dense array EEG caps, as well as amplifiers capable of recording low frequencies, have disclosed multitude of brain activities that have as yet been overlooked. In the practical part of this video, we show how a multimodal, dense array EEG study is performed in neonatal intensive care unit from a preterm baby in the incubator. The video demonstrates preparation of the baby and incubator, application of the EEG cap, and performance of the sensory stimulations. PMID:22371054

Stjerna, Susanna; Voipio, Juha; Metsäranta, Marjo; Kaila, Kai; Vanhatalo, Sampsa

2012-01-01

133

Modulation of cortical activity as a result of voluntary postural sway direction: an EEG study  

PubMed Central

There is increasing evidence demonstrating the role of the cerebral cortex in human postural control. Modulation of EEG both in voltage and frequency domains has been observed preceding and following self-paced postural movements and those induced by external perturbations. The current study set out to provide additional evidence regarding the role of cerebral cortex in human postural control by specifically examining modulation of EEG as a function of postural sway direction. Twelve neurologically normal subjects were instructed to produce self-paced voluntary postural sways in the anterior-posterior (AP) and medial-lateral (ML) directions. The center of pressure dynamics and EEG both in voltage and frequency domains were extracted by averaging and Morlet wavelet techniques, respectively. The amplitude of movement-related cortical potentials (MRCP) was significantly higher preceding ML sways. Also, time-frequency wavelet coefficients (TF) indicated differential modulation of EEG within alpha, beta and gamma bands as a function of voluntary postural sway direction. Thus, ML sway appear to be more difficult and energy demanding tasks than the AP sway as reflected in differential modulation of EEG. These results are discussed within the conceptual framework of differential patterns of brain activation as a result of postural task complexity. PMID:18639613

Slobounov, Semyon; Hallett, Mark; Cao, Cheng; Newell, Karl

2008-01-01

134

Methods of analysis of nonstationary EEGs, with emphasis on segmentation techniques: a comparative review.  

PubMed

Methods for analysis of nonstationary EEGs, that is, EEGs whose patterns undergo changes with time (e.g., alpha blocking, paroxysmal slow waves, onset of drowsiness/sleep, but excluding spikes/sharp waves) are reviewed. The concepts of stationarity and nonstationarity, and general techniques for their evaluation, are discussed. Simpler methods for monitoring for nonstationarity include running determinations of average amplitude and average period or interval. Piecewise stationary analysis includes characterization, by spectra obtained by fast Fourier transform or by autoregressive modeling, of sections of EEGs preselected to be stationary. In Kalman filtering, the autoregressive model itself becomes time-varying. Segmentation of the EEG into stationary lengths can be carried out on a fixed-interval basis (i.e., of successive, e.g., 1-s intervals), with clustering (grouping) or classification according to the features (e.g., spectra) of each interval, and concatenation of adjacent similar intervals. Alternatively, in adaptive (variable-interval) segmentation, the EEG is continuously monitored automatically for any significant departure from stationarity, and segment boundaries are placed accordingly. A number of applications of the various methods are included, with examples of succinct summary displays. Problems and prospects are discussed. PMID:3916847

Barlow, J S

1985-07-01

135

The Effect of Pre vs. Post-Reward Attainment on EEG Asymmetry in Melancholic Depression  

PubMed Central

Clinical investigators have long theorized about the role of reward processing and positive affect in depression. One theory posits that compared to nonmelancholic depressives, melancholic depressives experience less consummatory (i.e., post-reward), but comparably low anticipatory (prior to reward), positive affect. We tested whether frontal EEG asymmetry, a putative marker of the anticipatory reward system, is present only before an individual receives a reward or also after receiving a reward (i.e., during consummatory reward processing). We also examined whether melancholic depression, a condition characterized by a deficit in consummatory reward processing, is associated with abnormal EEG asymmetries in alphab and power. Effects in other frequency bands (delta, theta, or beta) were also explored. EEG was recorded in 34 controls, 48 nonmelancholic depressives, and 17 melancholic depressives during a slot machine task designed to elicit anticipatory and consummatory reward processing. Results indicated that, for alpha, the frontal EEG asymmetry of greater relative left activity was specific to anticipatory reward processing. During the consummatory phase, individuals with melancholic depression exhibited different posterior EEG asymmetries than individuals with nonmelancholic depression and controls at a trend level. This second finding was largely due to melancholics exhibiting relatively lower right posterior activity and nonmelancholics exhibiting relatively lower left activity. These results suggest that a posterior asymmetry may be a marker for melancholic depression and aberrant consummatory reward processing. PMID:21111010

Shankman, Stewart A.; Sarapas, Casey; Klein, Daniel N.

2010-01-01

136

EEG mapping in seasonal affective disorder  

Microsoft Academic Search

Given that the nature of hemispheric dysfunction is different in heterogeneous disorders, in the present investigation EEG power mapping was applied to establish neurophysiological profiles that might potentially discriminate patients with seasonal affective disorder (SAD) among other affective disorders. The baseline resting EEG activity was recorded from 31 depressed SAD patients and 30 controls. Power in the delta, theta-1, theta-2,

Nina V Volf; Natalia R Passynkova

2002-01-01

137

Differences in Cognitive Processes between Gifted, Intelligent, Creative, and Average Individuals While Solving Complex Problems: An EEG Study.  

ERIC Educational Resources Information Center

Studied differences in cognitive processes related to creativity and intelligence using EEG coherence and power measures in the lower and upper alpha bands. Results of 2 experiments involving 49 and 48 right-handed student teachers suggest that creativity and intelligence are different abilities that also differ in the neurological activity…

Jausovec, Norbert

2000-01-01

138

Asthma phenotypes  

Microsoft Academic Search

The many roads leading to the syndrome of asthma have proven to be intricately interconnected. The chronic inflammation of\\u000a asthma is characterized by airway hyperreactivity and variable reversibility. Past classification systems relied on assessment\\u000a of daily impairment and the distinction between intrinsic (nonallergic) and extrinsic (allergic). With more precise asthma\\u000a phenotypes, association studies likely will have greater significance. In addition,

Steve Handoyo; Lanny J. Rosenwasser

2009-01-01

139

Simultaneous EEG-fMRI at ultra-high field: Artifact prevention and safety assessment.  

PubMed

The simultaneous recording of scalp electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) can provide unique insights into the dynamics of human brain function, and the increased functional sensitivity offered by ultra-high field fMRI opens exciting perspectives for the future of this multimodal approach. However, simultaneous recordings are susceptible to various types of artifacts, many of which scale with magnetic field strength and can seriously compromise both EEG and fMRI data quality in recordings above 3T. The aim of the present study was to implement and characterize an optimized setup for simultaneous EEG-fMRI in humans at 7T. The effects of EEG cable length and geometry for signal transmission between the cap and amplifiers were assessed in a phantom model, with specific attention to noise contributions from the MR scanner coldheads. Cable shortening (down to 12cm from cap to amplifiers) and bundling effectively reduced environment noise by up to 84% in average power and 91% in inter-channel power variability. Subject safety was assessed and confirmed via numerical simulations of RF power distribution and temperature measurements on a phantom model, building on the limited existing literature at ultra-high field. MRI data degradation effects due to the EEG system were characterized via B0 and B1(+) field mapping on a human volunteer, demonstrating important, although not prohibitive, B1 disruption effects. With the optimized setup, simultaneous EEG-fMRI acquisitions were performed on 5 healthy volunteers undergoing two visual paradigms: an eyes-open/eyes-closed task, and a visual evoked potential (VEP) paradigm using reversing-checkerboard stimulation. EEG data exhibited clear occipital alpha modulation and average VEPs, respectively, with concomitant BOLD signal changes. On a single-trial level, alpha power variations could be observed with relative confidence on all trials; VEP detection was more limited, although statistically significant responses could be detected in more than 50% of trials for every subject. Overall, we conclude that the proposed setup is well suited for simultaneous EEG-fMRI at 7T. PMID:25449743

Jorge, João; Grouiller, Frédéric; Ipek, Ozlem; Stoermer, Robert; Michel, Christoph M; Figueiredo, Patrícia; van der Zwaag, Wietske; Gruetter, Rolf

2015-01-15

140

EEG findings in fetal alcohol syndrome and Down syndrome children  

Microsoft Academic Search

Results from previous studies evaluating the electroencephalograms (EEGs) of infants bom to alcoholic mothers suggest that the neonatal EEG may be a sensitive measure of prenatal ethanol exposure. Few studies, however, have examined EEG records of adolescent children with fetal alcohol syndrome (FAS). The present study investigated the resting EEG recordings of 18 matched triads of FAS, Down syndrome, and

W. M. Kaneko; E. L. Phillips; E. P. Riley; C. L. Ehlers

1996-01-01

141

Golf putt outcomes are predicted by sensorimotor cerebral EEG rhythms  

PubMed Central

It is not known whether frontal cerebral rhythms of the two hemispheres are implicated in fine motor control and balance. To address this issue, electroencephalographic (EEG) and stabilometric recordings were simultaneously performed in 12 right-handed expert golfers. The subjects were asked to stand upright on a stabilometric force platform placed at a golf green simulator while playing about 100 golf putts. Balance during the putts was indexed by body sway area. Cortical activity was indexed by the power reduction in spatially enhanced alpha (8–12 Hz) and beta (13–30 Hz) rhythms during movement, referred to as the pre-movement period. It was found that the body sway area displayed similar values in the successful and unsuccessful putts. In contrast, the high-frequency alpha power (about 10–12 Hz) was smaller in amplitude in the successful than in the unsuccessful putts over the frontal midline and the arm and hand region of the right primary sensorimotor area; the stronger the reduction of the alpha power, the smaller the error of the unsuccessful putts (i.e. distance from the hole). These results indicate that high-frequency alpha rhythms over associative, premotor and non-dominant primary sensorimotor areas subserve motor control and are predictive of the golfer's performance. PMID:17947315

Babiloni, Claudio; Del Percio, Claudio; Iacoboni, Marco; Infarinato, Francesco; Lizio, Roberta; Marzano, Nicola; Crespi, Gianluca; Dassù, Federica; Pirritano, Mirella; Gallamini, Michele; Eusebi, Fabrizio

2008-01-01

142

Electroencephalogram (EEG) in the management of epilepsy in children.  

PubMed

Electroencephalogram (EEG) has an important role in the management of seizure disorder in children. It helps in diagnosis and classification of epilepsy, choosing of antiepileptic medication and prediction of prognosis. When history of epilepsy is unclear, EEG can help to distinguish epileptiform discharges from its counterpart. But EEG has limitations. In epilepsy, EEG has variable range of sensitivity and specificity. Hereby, during interpretation of EEG, clinical situation should not be ignored. Interictal EEG has important diagnostic and prognostic value in epilepsy. But caution is needed during evaluation of significance of interictal epileptiform discharge (IED). Methods like recording of EEG in awake and sleep state, hyperventilation and photic stimulation enhances the yield of interictal EEG. Long term EEG recording has an important role in the assessment of patients who present diagnostic or management difficulties following clinical evaluation and routine EEG. PMID:24858177

Das, J C

2014-04-01

143

Early EEG Improvement after Ketogenic Diet Initiation  

PubMed Central

Purpose This study examines electroencephalographic (EEG) changes in children with medication resistant epilepsy treated with the ketogenic diet (KD). Methods Routine EEGs were obtained prior to KD initiation, then one month and three months later. Changes in EEG background slowing and frequency of interictal epileptiform discharges (IEDs) were evaluated using power spectrum analysis and manual determination of spike index. KD responders were compared to non-responders to determine if baseline or early EEG characteristics predicted treatment response (>50% seizure reduction) at three months. Results Thirty-seven patients were evaluated. No differences in baseline EEG features were found between responder groups. Frequency of IEDs declined in 65% of patients as early as one month, by a median of 13.6% (IQR 2-33). Those with a ten percent or greater improvement in IED frequency at one month were greater than six times more likely to be KD responders (OR 6.5 95% CI 0.85 to 75. p=0.03). Qualitative and quantitative measures of EEG background slowing improved in the whole cohort, but did not predict responder status. Conclusion Baseline predictors of KD response remain elusive. Most patients experienced a reduction in IEDs and improvement in EEG background slowing after KD initiation. Reduction of IEDs at one month strongly predicted KD responder status at three months. PMID:21345653

Kessler, Sudha Kilaru; Gallagher, Paul R.; Shellhaas, Renée A.; Clancy, Robert R.; Bergqvist, A.G. Christina

2011-01-01

144

ORIGINAL PAPER Sensitivity of EEG and MEG to the N1 and P2 Auditory Evoked  

E-print Network

of electroencephalography (EEG) and magnetoencephalography (MEG) to these neural correlates of sensation. Simultaneous EEG in humans. For instance, in theory the combination of EEG (electroencephalography) and MEG

Roberts, Larry

145

Simultaneous EEG and fMRI for Event Related Studies  

Microsoft Academic Search

Objective: EEG and functional MRI potentially provide complementary information about the brain, yet high quality EEG is difficult to acquire during MR scanning because of mutual artifacts induced. Many groups have circumvented this difficulty by interleaving MRI volume acquisitions with EEG. However, for event-related EEG\\/fMRI studies, particularly those directed at single-trial analysis, high-density, high-quality, uninterrupted EEG is necessary. We have

Robin I Goldman; A D Gerson; M S Cohen; T R Brown; P R Sajda

146

Circadian variation of EEG power spectra in NREM and REM sleep in humans: dissociation from body temperature  

NASA Technical Reports Server (NTRS)

In humans, EEG power spectra in REM and NREM sleep, as well as characteristics of sleep spindles such as their duration, amplitude, frequency and incidence, vary with circadian phase. Recently it has been hypothesized that circadian variations in EEG spectra in humans are caused by variations in brain or body temperature and may not represent phenomena relevant to sleep regulatory processes. To test this directly, a further analysis of EEG power spectra - collected in a forced desynchrony protocol in which sleep episodes were scheduled to a 28-h period while the rhythms of body temperature and plasma melatonin were oscillating at their near 24-h period - was carried out. EEG power spectra were computed for NREM and REM sleep occurring between 90-120 and 270-300 degrees of the circadian melatonin rhythm, i.e. just after the clearance of melatonin from plasma in the 'morning' and just after the 'evening' increase in melatonin secretion. Average body temperatures during scheduled sleep at these two circadian phases were identical (36.72 degrees C). Despite identical body temperatures, the power spectra in NREM sleep were very different at these two circadian phases. EEG activity in the low frequency spindle range was significantly and markedly enhanced after the evening increase in plasma melatonin as compared to the morning phase. For REM sleep, significant differences in power spectra during these two circadian phases, in particular in the alpha range, were also observed. The results confirm that EEG power spectra in NREM and REM sleep vary with circadian phase, suggesting that the direct contribution of temperature to the circadian variation in EEG power spectra is absent or only minor, and are at variance with the hypothesis that circadian variations in EEG power spectra are caused by variations in temperature.

Dijk, D. J.

1999-01-01

147

Enabling computer decisions based on EEG input  

NASA Technical Reports Server (NTRS)

Multilayer neural networks were successfully trained to classify segments of 12-channel electroencephalogram (EEG) data into one of five classes corresponding to five cognitive tasks performed by a subject. Independent component analysis (ICA) was used to segregate obvious artifact EEG components from other sources, and a frequency-band representation was used to represent the sources computed by ICA. Examples of results include an 85% accuracy rate on differentiation between two tasks, using a segment of EEG only 0.05 s long and a 95% accuracy rate using a 0.5-s-long segment.

Culpepper, Benjamin J.; Keller, Robert M.

2003-01-01

148

Alpha attenuation soon after closing the eyes as an objective indicator of sleepiness.  

PubMed

Attenuation of alpha rhythm in occipital derivation serves as a reliable electroencephalographic (EEG) marker of sleep onset. If such attenuation not only coincides with but also anticipates sleep onset, objective evaluation of sleepiness of permanently waking individuals might be facilitated by probing alpha attenuation immediately after closing eyes. We tested whether alpha-based EEG indexes reflect self-scored sleepiness and objectively measured waking ability. A total of 15 young adults self-scored their sleepiness before and after recording of their resting EEG with a 2-h interval in the course of 43-61-h wakefulness. For each EEG record, power spectra were calculated on 2-min intervals of the eyes open section and on five following 1-min intervals of the eyes closed section. Aking ability was assessed as latency to sleep onset marked by zero-crossing decline of such EEG indexes as alpha-theta power difference in occipital derivation and scores on the second principal component of the EEG spectrum in frontal and occipital derivations. Alpha attenuation during the first minute with eyes closed was found to be significantly related to the levels of subjective sleepiness and waking ability. The relationship between alpha attenuation and subjective sleepiness was confirmed by analysing 1-min eyes closed EEG recordings obtained with a 3-h interval in the course of 24-h sustained wakefulness of 130 adolescents and adults. We concluded that such 1-min eyes closed EEG recordings might be used for simple and quick measurements of sleepiness and waking ability in experimental and field studies of permanently waking individuals. PMID:25224885

Putilov, Arcady A; Donskaya, Olga G

2014-12-01

149

Separation of circadian and wake duration-dependent modulation of EEG activation during wakefulness  

NASA Technical Reports Server (NTRS)

The separate contribution of circadian rhythmicity and elapsed time awake on electroencephalographic (EEG) activity during wakefulness was assessed. Seven men lived in an environmental scheduling facility for 4 weeks and completed fourteen 42.85-h 'days', each consisting of an extended (28.57-h) wake episode and a 14.28-h sleep opportunity. The circadian rhythm of plasma melatonin desynchronized from the 42.85-h day. This allowed quantification of the separate contribution of circadian phase and elapsed time awake to variation in EEG power spectra (1-32 Hz). EEG activity during standardized behavioral conditions was markedly affected by both circadian phase and elapsed time awake in an EEG frequency- and derivation-specific manner. The nadir of the circadian rhythm in alpha (8-12 Hz) activity in both fronto-central and occipito-parietal derivations occurred during the biological night, close to the crest of the melatonin rhythm. The nadir of the circadian rhythm of theta (4.5-8 Hz) and beta (20-32 Hz) activity in the fronto-central derivation was located close to the onset of melatonin secretion, i.e. during the wake maintenance zone. As time awake progressed, delta frequency (1-4.5 Hz) and beta (20-32 Hz) activity rose monotonically in frontal derivations. The interaction between the circadian and wake-dependent increase in frontal delta was such that the intrusion of delta was minimal when sustained wakefulness coincided with the biological day, but pronounced during the biological night. Our data imply that the circadian pacemaker facilitates frontal EEG activation during the wake maintenance zone, by generating an arousal signal that prevents the intrusion of low-frequency EEG components, the propensity for which increases progressively during wakefulness.

Cajochen, C.; Wyatt, J. K.; Czeisler, C. A.; Dijk, D. J.

2002-01-01

150

Optimal set of EEG features for emotional state classification and trajectory visualization in Parkinson's disease.  

PubMed

In addition to classic motor signs and symptoms, individuals with Parkinson's disease (PD) are characterized by emotional deficits. Ongoing brain activity can be recorded by electroencephalograph (EEG) to discover the links between emotional states and brain activity. This study utilized machine-learning algorithms to categorize emotional states in PD patients compared with healthy controls (HC) using EEG. Twenty non-demented PD patients and 20 healthy age-, gender-, and education level-matched controls viewed happiness, sadness, fear, anger, surprise, and disgust emotional stimuli while fourteen-channel EEG was being recorded. Multimodal stimulus (combination of audio and visual) was used to evoke the emotions. To classify the EEG-based emotional states and visualize the changes of emotional states over time, this paper compares four kinds of EEG features for emotional state classification and proposes an approach to track the trajectory of emotion changes with manifold learning. From the experimental results using our EEG data set, we found that (a) bispectrum feature is superior to other three kinds of features, namely power spectrum, wavelet packet and nonlinear dynamical analysis; (b) higher frequency bands (alpha, beta and gamma) play a more important role in emotion activities than lower frequency bands (delta and theta) in both groups and; (c) the trajectory of emotion changes can be visualized by reducing subject-independent features with manifold learning. This provides a promising way of implementing visualization of patient's emotional state in real time and leads to a practical system for noninvasive assessment of the emotional impairments associated with neurological disorders. PMID:25109433

Yuvaraj, R; Murugappan, M; Ibrahim, Norlinah Mohamed; Sundaraj, Kenneth; Omar, Mohd Iqbal; Mohamad, Khairiyah; Palaniappan, R

2014-12-01

151

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

PubMed Central

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 the brain’s resting state. We aimed to investigate novel potential markers of chronic pain in the resting state EEG of patients with chronic pancreatitis. Participants Resting state EEG data from 16 patients with persistent abdominal pain due to chronic pancreatitis (CP) were compared to data from healthy controls matched for age, sex and education. Methods The peak alpha frequency (PAF) and power amplitude in the alpha band (7.5–13 Hz) were compared between groups in four regions of interest (frontal, central, parietal, and occipital) and were correlated with pain duration. Results The average PAF was lowered in CP patients compared with that in healthy controls, observed as a statistically significant between-group effect (mean 9.9 versus 9.5 Hz; P=0.049). Exploratory post hoc analysis of average PAF per region of interest revealed a significant difference, particularly in the parietal and occipital regions. In addition, we observed a significant correlation between pain duration and PAF and showed increased shifts in PAF with longer pain durations. No significant group differences were found in peak power amplitudes. Conclusion CP pain is associated with alterations in spontaneous brain activity, observed as a shift toward lower PAF. This shift correlates with the duration of pain, which demonstrates that PAF has the potential to be a clinically feasible biomarker for chronic pain. These findings could be helpful for assisting diagnosis, establishing optimal treatment, and studying efficacy of new therapeutic agents in chronic pain patients. PMID:24379694

de Vries, Marjan; Wilder-Smith, Oliver HG; Jongsma, Marijtje LA; van den Broeke, Emanuel N; Arns, Martijn; van Goor, Harry; van Rijn, Clementina M

2013-01-01

152

EEG  

MedlinePLUS

... abnormal structure in the brain (such as a brain tumor ) Tissue death due to a blockage in blood flow (cerebral infarction) Drug or alcohol abuse Head injury Migraines (in some ... Sleep disorder (such as narcolepsy ) Swelling of the brain (edema)

153

Automated characterization of multiple alpha peaks in multi-site electroencephalograms.  

PubMed

The identification of alpha rhythm in the human electroencephalogram (EEG) is generally a laborious task involving visual inspection of the spectrum. Moreover the occurrence of multiple alpha rhythms is often overlooked. This paper seeks to automate the process of identifying alpha peaks and quantifying their frequency, amplitude and width as a function of position on the scalp. Experimental EEG was fitted with parameterized spectra spanning the alpha range, with results categorized by multi-site criteria into three distinct classes: no distinguishable alpha peak, a single alpha peak, and two alpha peaks. The technique avoids visual bias, integrates spatial information, and is automated. We show that multiple alpha peaks are a common feature of many spectra. PMID:18083237

Chiang, A K I; Rennie, C J; Robinson, P A; Roberts, J A; Rigozzi, M K; Whitehouse, R W; Hamilton, R J; Gordon, E

2008-03-15

154

The phase of ongoing EEG oscillations predicts visual perception.  

PubMed

Oscillations are ubiquitous in electrical recordings of brain activity. While the amplitude of ongoing oscillatory activity is known to correlate with various aspects of perception, the influence of oscillatory phase on perception remains unknown. In particular, since phase varies on a much faster timescale than the more sluggish amplitude fluctuations, phase effects could reveal the fine-grained neural mechanisms underlying perception. We presented brief flashes of light at the individual luminance threshold while EEG was recorded. Although the stimulus on each trial was identical, subjects detected approximately half of the flashes (hits) and entirely missed the other half (misses). Phase distributions across trials were compared between hits and misses. We found that shortly before stimulus onset, each of the two distributions exhibited significant phase concentration, but at different phase angles. This effect was strongest in the theta and alpha frequency bands. In this time-frequency range, oscillatory phase accounted for at least 16% of variability in detection performance and allowed the prediction of performance on the single-trial level. This finding indicates that the visual detection threshold fluctuates over time along with the phase of ongoing EEG activity. The results support the notion that ongoing oscillations shape our perception, possibly by providing a temporal reference frame for neural codes that rely on precise spike timing. PMID:19535598

Busch, Niko A; Dubois, Julien; VanRullen, Rufin

2009-06-17

155

Two channel EEG thought pattern classifier.  

PubMed

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 % PMID:17946455

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

2006-01-01

156

EEG-Based Personalized Digital Experience  

Microsoft Academic Search

\\u000a To make human computer interfaces more immersive and intuitive, a new dimension could be added. Real-time brain state recognition\\u000a from EEG including emotion recognition and level of concentration recognition would make an access to information more adaptive\\u000a and personalized. Modern EEG techniques give us an easy and portable way to monitor brain activities by using suitable signal\\u000a processing and classification

Olga Sourina; Yisi Liu; Qiang Wang; Minh Khoa Nguyen

157

Mobile Robots and EEG - A Review  

Microsoft Academic Search

In this paper we present an overview of recent methods of controlling mobile robots with emphasis on evolutionary approaches\\u000a of robot control. Development of recent electroencephalogram (EEG) based Brain-computer interfaces (BCI) are discussed with\\u000a the main reference to EEG analysis where brain electrical activity is classified with the intent of generating output commands.\\u000a Recent attempts to control a mobile robot

K. A. Plant; P. V. S. Ponnapalli; D. M. Southall

2007-01-01

158

Short-Term EEG Spectral Pattern as a Single Event in EEG Phenomenology  

PubMed Central

Spectral decomposition, to this day, still remains the main analytical paradigm for the analysis of EEG oscillations. However, conventional spectral analysis assesses the mean characteristics of the EEG power spectra averaged out over extended periods of time and/or broad frequency bands, thus resulting in a “static” picture which cannot reflect adequately the underlying neurodynamic. A relatively new promising area in the study of EEG is based on reducing the signal to elementary short-term spectra of various types in accordance with the number of types of EEG stationary segments instead of using averaged power spectrum for the whole EEG. It is suggested that the various perceptual and cognitive operations associated with a mental or behavioural condition constitute a single distinguishable neurophysiological state with a distinct and reliable spectral pattern. In this case, one type of short-term spectral pattern may be considered as a single event in EEG phenomenology. To support this assumption the following issues are considered in detail: (a) the relations between local EEG short-term spectral pattern of particular type and the actual state of the neurons in underlying network and a volume conduction; (b) relationship between morphology of EEG short-term spectral pattern and the state of the underlying neurodynamical system i.e. neuronal assembly; (c) relation of different spectral pattern components to a distinct physiological mechanism; (d) relation of different spectral pattern components to different functional significance; (e) developmental changes of spectral pattern components; (f) heredity of the variance in the individual spectral pattern and its components; (g) intra-individual stability of the sets of EEG short-term spectral patterns and their percent ratio; (h) discrete dynamics of EEG short-term spectral patterns. Functional relevance (consistency) of EEG short-term spectral patterns in accordance with the changes of brain functional state, cognitive task and with different neuropsychopathologies is demonstrated. PMID:21379390

Fingelkurts, Al. A; Fingelkurts, An. A

2010-01-01

159

A review of the effects of hypoxia, sleep deprivation and transcranial magnetic stimulation on EEG activity in humans: challenges for drug discovery for Alzheimer's disease.  

PubMed

Different kinds of challenge can alter cognitive process and electroencephalographic (EEG) rhythms in humans. This can provide an alternative paradigms to evaluate treatment effects in drug discovery. Here, we report recent findings on the effects of challenges represented by sleep deprivation (SD), transient hypoxia, and transcranial magnetic stimulation (TMS) in healthy volunteers on cognitive processes and EEG rhythms to build a knowledge platform for novel research for drug discovery in AD Alzheimer's disease (AD). Sleep pressure enhanced frontal delta rhythms (< 4 Hz) during the night, while SD increased slow rhythms in the theta range (4-7 Hz), and reduced resting state alpha rhythms (8-12 Hz) after the following day. Furthermore, SD transiently affected cognitive performance. In contrast, transient experimental hypoxia induced abnormal posterior resting state delta and alpha rhythms in healthy volunteers that resemble the abnormal EEG rhythms typically recorded in AD patients. However, the relationship between the cognitive and EEG effects of such challenges is poorly understood. TMS reversibly interfered with higher brain functions during EEG recordings, but few studies have investigated the relationship between the cognitive and EEG effects of TMS. In conclusion, SD is the most mature challenge model for testing new drugs for AD. Future investigation is needed to better understand the opportunities offered by TMS and hypoxia challenges. PMID:24635844

Babiloni, Claudio; Del Percio, Claudio; Lizio, Roberta; Infarinato, Francesco; Blin, Olivier; Bartres-Faz, David; Dix, Sophie L; Bentivoglio, Marina; Soricelli, Andrea; Bordet, Regis; Rossini, Paolo M; Richardson, Jill C

2014-01-01

160

Using EEG to explore how rTMS produces its effects on behavior.  

PubMed

A commonly held view is that, when delivered during the performance of a task, repetitive TMS (rTMS) influences behavior by producing transient "virtual lesions" in targeted tissue. However, findings of rTMS-related improvements in performance are difficult to reconcile with this assumption. With regard to the mechanism whereby rTMS influences concurrent task performance, a combined rTMS/EEG study conducted in our lab has revealed a complex set of relations between rTMS, EEG activity, and behavioral performance, with the effects of rTMS on power in the alpha band and on alpha:gamma phase synchrony each predicting its effect on behavior. These findings suggest that rTMS influences performance by biasing endogenous task-related oscillatory dynamics, rather than creating a "virtual lesion". To further differentiate these two alternatives, in the present study we compared the effects of 10 Hz rTMS on neural activity with the results of an experiment in which rTMS was replaced with 10 Hz luminance flicker. We reasoned that 10 Hz flicker would produce widespread entrainment of neural activity to the flicker frequency, and comparison of these EEG results with those from the rTMS study would shed light on whether the latter also reflected entrainment to an exogenous stimulus. Results revealed pronounced evidence for "entrainment noise" produced by 10 Hz flicker-increased oscillatory power and inter-trial coherence (ITC) at the driving frequency, and increased alpha:gamma phase synchronization-that were nonetheless largely uncorrelated with behavior. This contrasts markedly with 10-Hz rTMS, for which the only evidence for stimulation-induced noise, elevated ITC at 30 Hz, differed qualitatively from the flicker results. Simultaneous recording of the EEG thus offers an important means of directly testing assumptions about how rTMS exerts its effects on behavior. PMID:19915972

Johnson, Jeffrey S; Hamidi, Massihullah; Postle, Bradley R

2010-01-01

161

EEG gamma coherence and other correlates of subjective reports during ayahuasca experiences.  

PubMed

The current study examined QEEG power and coherence of ayahuasca experiences with two experienced participants in a Brazilian jungle setting. An exploratory case series design was adopted for naturalistic field research. EEGs recorded during visual imagery was compared to eyes-closed baselines. The most important findings were increases in global EEG coherence in the 36-44 Hz and 50-64 Hz frequency bands for both subjects. Widely distributed cortical hyper-coherence seems reasonable given the intense synesthesia during ayahuasca experiences. Other findings include increased modal EEG alpha frequency and global power decreases across the cortex in most frequency bands, which concur with the EEG of psychedelics literature. Exploratory analysis revealed the usefulness of analyzing single Hz bins over the standard wide-band analysis. The discovery-oriented naturalistic approach developed for this study resulted in potentially important findings. We believe that finding increases in global gamma coherence during peak psychedelic experiences might contribute to the discussion of binding theory. Also, in light of recent research with gamma coherence during advanced meditative conditions, our findings might further the comparison of shamanic psychedelic practices with meditation. PMID:16149330

Stuckey, David E; Lawson, Robert; Luna, Luis Eduardo

2005-06-01

162

Nonconvulsive status epilepticus and Creutzfeldt–Jakob-like EEG changes in a case of lithium toxicity  

PubMed Central

We report a case of a 63-year-old lady with bipolar affective disorder on lithium who was brought to our emergency center in a comatose state. Neurologically, the patient was comatose and had generalized hypotonia and hyporeflexia. Lithium toxicity was considered. Laboratory examinations revealed leukocytosis, normal blood sugar, blood level of lithium was 4.7 mEq/L and she had renal dysfunction. Cerebrospinal fluid examination and cranial computerized tomography were unremarkable. Blood lithium level was 4.7 mEq/L. Hemodialysis was initiated. However, in spite of dialysis and decreasing lithium levels, the patient remained unconscious. A possibility of nonconvulsive status epilepticus was considered; hence, EEG was advised. The EEG demonstrated bihemispheric slowing (4- to 5-Hz theta range) with bilateral periodic triphasic waves of 1- to 2-Hz frequency, similar to the EEG changes seen in Creutzfeldt–Jakob disease. She was started on lorazepam. Her sensorium improved gradually, which correlated with the decline in blood lithium levels. A normal background alpha rhythm on EEG was ensured prior to discharge. At discharge, clinically, she had recovered completely, with no apparent neurological deficit or cognitive impairment. This case highlights the importance of therapeutic drug-level monitoring of lithium, especially where toxicity is suspected, and the important role electroencephalography plays in diagnosing NCSE and its management. PMID:25667908

Madhusudhan, B.K.

2014-01-01

163

Mal-adaptation of event-related EEG responses preceding performance errors.  

PubMed

Recent EEG and fMRI evidence suggests that behavioral errors are foreshadowed by systematic changes in brain activity preceding the outcome by seconds. In order to further characterize this type of error precursor activity, we investigated single-trial event-related EEG activity from 70 participants performing a modified Eriksen flanker task, in particular focusing on the trial-by-trial dynamics of a fronto-central independent component that previously has been associated with error and feedback processing. The stimulus-locked peaks in the N2 and P3 latency range in the event-related averages showed expected compatibility and error-related modulations. In addition, a small pre-stimulus negative slow wave was present at erroneous trials. Significant error-preceding activity was found in local stimulus sequences with decreased conflict in the form of less negativity at the N2 latency (310-350 ms) accumulating across five trials before errors; concomitantly response times were speeding across trials. These results illustrate that error-preceding activity in event-related EEG is associated with the performance monitoring system and we conclude that the dynamics of performance monitoring contribute to the generation of error-prone states in addition to the more remote and indirect effects in ongoing activity such as posterior alpha power in EEG and default mode drifts in fMRI. PMID:20740080

Eichele, Heike; Juvodden, Hilde T; Ullsperger, Markus; Eichele, Tom

2010-01-01

164

Outpatient ambulatory EEG as an option for epilepsy surgery evaluation instead of inpatient EEG telemetry?  

PubMed Central

Outpatient ambulatory EEG is more cost-effective than inpatient EEG telemetry and may provide adequate seizure localization in a presurgical evaluation. A 51-year-old right-handed male had been unable to work or drive since the age of 35 due to intractable partial onset epilepsy. A 72-hour outpatient ambulatory EEG recorded 18 seizures from the right temporal region. No epileptiform activity was seen in the left hemisphere. Magnetic resonance imaging showed right mesial temporal sclerosis as well as an area of encephalomalacia at the medial inferior right temporal lobe. Neuropsychological assessment found that the patient was a good neurosurgery candidate. At this point, the patient was considered to be a candidate for a right temporal lobectomy. A standard right temporal lobectomy was performed. The patient has been seizure-free for 10 months after the surgery. Follow-up EEGs show no epileptiform activity. The patient is preparing to go back to work, and his driver's license was reinstated 9 months postsurgery. Neuropsychological reassessment is pending, but no apparent change in cognition has been noticed by the patient or his family. Cases with a high congruence between diagnostic imaging and the EEG abnormalities identified in the portable EEG may provide enough information regarding seizure frequency and localization to eliminate the need for inpatient EEG telemetry in the evaluation of patients for epilepsy surgery. We believe that the use of aEEG in preoperative planning should be restricted to cases of TLE and to patients with a high frequency of seizures.

Rizvi, Syed A.; Téllez Zenteno, José F.; Crawford, Sara L.; Wu, Adam

2013-01-01

165

EEG Biofeedback as a Treatment for Substance Use Disorders: Review, Rating of Efficacy, and Recommendations for Further Research  

PubMed Central

Electroencephalographic (EEG) biofeedback has been employed in substance use disorder (SUD) over the last three decades. The SUD is a complex series of disorders with frequent comorbidities and EEG abnormalities of several types. EEG biofeedback has been employed in conjunction with other therapies and may be useful in enhancing certain outcomes of therapy. Based on published clinical studies and employing efficacy criteria adapted by the Association for Applied Psychophysiology and Biofeedback and the International Society for Neurofeedback and Research, alpha theta training—either alone for alcoholism or in combination with beta training for stimulant and mixed substance abuse and combined with residential treatment programs, is probably efficacious. Considerations of further research design taking these factors into account are discussed and descriptions of contemporary research are given. PMID:18214670

Cannon, Rex L.; Trudeau, David L.

2008-01-01

166

EEG non-linear feature extraction using correlation dimension and Hurst exponent.  

PubMed

In this work, we evaluated the differences between epileptic electroencephalogram (EEG) and interictal EEG by computing some non-linear features. Correlation dimension (CD) and Hurst exponent (H) were calculated for 100 segments of epileptic EEG and 100 segments of interictal EEG. A comparison was made between epileptic EEG and interictal EEG in those non-linear parameters. Results show that the mean values of CD are 2.64 for epileptic EEG and 4.55 for interictal EEG. We also calculated approximate entropy (ApEn) of those EEG signals. The mean values of ApEn are 0.90 for epileptic EEG and 4.55 for interictal EEG. The values of CD and ApEn of epileptic EEG are generally lower than those of interictal EEG, indicating less complexity of EEG signals during seizures. The mean values of Hurst exponent are 0.19 for epileptic EEG and 0.29 for interictal EEG. Hurst exponents for epileptic EEG and interictal EEG are both <0.5. This indicates that both epileptic and interictal EEGs show long-range anticorrelation. The value of Hurst exponent of epileptic EEG signals is lower than that of interictal EEG signals, showing that the degree of anticorrelation of epileptic EEG signals is larger than that of interictal EEG. Hence, the non-linear parameters such as CD and Hurst exponent can help interpret epileptic and interictal EEGs and their neurodynamics. PMID:22080990

Geng, Shujuan; Zhou, Weidong; Yuan, Qi; Cai, Dongmei; Zeng, Yanjun

2011-11-01

167

Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders  

ERIC Educational Resources Information Center

An emerging focus of research on autism spectrum disorder (ASD) targets the identification of early-developing ASD endophenotypes using infant siblings of affected children. One potential neural endophenotype is resting frontal electroencephalogram (EEG) alpha asymmetry, a metric of hemispheric organization. Here, we examined the development of…

Gabard-Durnam, Laurel; Tierney, Adrienne L.; Vogel-Farley, Vanessa; Tager-Flusberg, Helen; Nelson, Charles A.

2015-01-01

168

Impact of Dronabinol on Quantitative Electroencephalogram (qEEG) Measures of Sleep in Obstructive Sleep Apnea Syndrome  

PubMed Central

Study Objectives: To determine the effects of dronabinol on quantitative electroencephalogram (EEG) markers of the sleep process, including power distribution and ultradian cycling in 15 patients with obstructive sleep apnea (OSA). Methods: EEG (C4-A1) relative power (% total) in the delta, theta, alpha, and sigma bands was quantified by fast Fourier transformation (FFT) over 28-second intervals. An activation ratio (AR = [alpha + sigma] / [delta + theta]) also was computed for each interval. To assess ultradian rhythms, the best-fitting cosine wave was determined for AR and each frequency band in each polysomnogram (PSG). Results: Fifteen subjects were included in the analysis. Dronabinol was associated with significantly increased theta power (p = 0.002). During the first half of the night, dronabinol decreased sigma power (p = 0.03) and AR (p = 0.03), and increased theta power (p = 0.0006). At increasing dronabinol doses, ultradian rhythms accounted for a greater fraction of EEG power variance in the delta band (p = 0.04) and AR (p = 0.03). Females had higher amplitude ultradian rhythms than males (theta: p = 0.01; sigma: p = 0.01). Decreasing AHI was associated with increasing ultradian rhythm amplitudes (sigma: p < 0.001; AR: p = 0.02). At the end of treatment, lower relative power in the theta band (p = 0.02) and lower AHI (p = 0.05) correlated with a greater decrease in sleepiness from baseline. Conclusions: This exploratory study demonstrates that in individuals with OSA, dronabinol treatment may yield a shift in EEG power toward delta and theta frequencies and a strengthening of ultradian rhythms in the sleep EEG. Citation: Farabi SS; Prasad B; Quinn L; Carley DW. Impact of dronabinol on quantitative electroencephalogram (qEEG) measures of sleep in obstructive sleep apnea syndrome. J Clin Sleep Med 2014;10(1):49-56. PMID:24426820

Farabi, Sarah S.; Prasad, Bharati; Quinn, Lauretta; Carley, David W.

2014-01-01

169

Serum alpha 1 antitrypsin and pulmonary emphysema.  

PubMed

Using isoelectric focusing (IEF) and radial immunodiffusion (RID) techniques, serum samples from 100 normal healthy adults and 21 patients with pulmonary emphysema were analysed to identify various alpha 1 antitrypsin phenotypes and the serum concentrations. Ten percent of the patients had low serum values. The normal or most common genetic form, MM, is the predominant phenotype in both controls and patients. PMID:8961698

Shahid, A; Siddiqui, A A; Aziz, S; Ansari, M; Zuberi, S J; Waqar, M A

1996-05-01

170

A Wearable UHF RFID-Based EEG System Artem Dementyev  

E-print Network

-free EEG system called EEGWISP, that uses a commercial ultra-high frequency (UHF) radio frequency is available. EEG analog circuit DRL Storage Capacitor WISP ADC MSP430 Reader PC RF 900 MHz RF Backscatter

Hochberg, Michael

171

Change in the characteristics of EEG color noise in Alzheimer's disease.  

PubMed

Neurophysiological experiments support the hypothesis of the presence of critical dynamics of brain activity. This is also manifested by power law of electroencephalography (EEG) power spectra, which can be described by the relation 1/f(alpha). This dependence is a result of internal interactions between parts of the brain and is probably required for optimal processing of information. In Alzheimer's disease, changes in the functional organization of the brain occur, which may be manifested by changes in the alpha coefficient. We compared the average values of alpha for 19 electrodes in the resting EEG record in 110 patients with moderate to severe Alzheimer's disease (Mini-Mental State Examination [MMSE] score = 10-19) with 110 healthy controls. Statistically, the most significant differences are present in the prefrontal areas. In addition to the prefrontal and frontal areas, the largest separation value in the evaluation of receiver operating characteristic (ROC) curves was recorded in the temporal area. The coefficient alpha has few false-positive results in the optimal operating point of the ROC curve, and is thereby highly specific for Alzheimer's disease. PMID:24131619

Vysata, Oldrich; Procházka, Ales; Mares, Jan; Rusina, Robert; Pazdera, Ladislav; Valis, Martin; Kukal, Jaromír

2014-07-01

172

Time-varying bispectral analysis of visually evoked multi-channel EEG  

NASA Astrophysics Data System (ADS)

Theoretical foundations of higher order spectral analysis are revisited to examine the use of time-varying bicoherence on non-stationary signals using a classical short-time Fourier approach. A methodology is developed to apply this to evoked EEG responses where a stimulus-locked time reference is available. Short-time windowed ensembles of the response at the same offset from the reference are considered as ergodic cyclostationary processes within a non-stationary random process. Bicoherence can be estimated reliably with known levels at which it is significantly different from zero and can be tracked as a function of offset from the stimulus. When this methodology is applied to multi-channel EEG, it is possible to obtain information about phase synchronization at different regions of the brain as the neural response develops. The methodology is applied to analyze evoked EEG response to flash visual stimulii to the left and right eye separately. The EEG electrode array is segmented based on bicoherence evolution with time using the mean absolute difference as a measure of dissimilarity. Segment maps confirm the importance of the occipital region in visual processing and demonstrate a link between the frontal and occipital regions during the response. Maps are constructed using bicoherence at bifrequencies that include the alpha band frequency of 8Hz as well as 4 and 20Hz. Differences are observed between responses from the left eye and the right eye, and also between subjects. The methodology shows potential as a neurological functional imaging technique that can be further developed for diagnosis and monitoring using scalp EEG which is less invasive and less expensive than magnetic resonance imaging.

Chandran, Vinod

2012-12-01

173

Estimation of Eye Closure Degree Using EEG Sensors and Its Application in Driver Drowsiness Detection  

PubMed Central

Currently, driver drowsiness detectors using video based technology is being widely studied. Eyelid closure degree (ECD) is the main measure of the video-based methods, however, drawbacks such as brightness limitations and practical hurdles such as distraction of the drivers limits its success. This study presents a way to compute the ECD using EEG sensors instead of video-based methods. The premise is that the ECD exhibits a linear relationship with changes of the occipital EEG. A total of 30 subjects are included in this study: ten of them participated in a simple proof-of-concept experiment to verify the linear relationship between ECD and EEG, and then twenty participated in a monotonous highway driving experiment in a driving simulator environment to test the robustness of the linear relationship in real-life applications. Taking the video-based method as a reference, the Alpha power percentage from the O2 channel is found to be the best input feature for linear regression estimation of the ECD. The best overall squared correlation coefficient (SCC, denoted by r2) and mean squared error (MSE) validated by linear support vector regression model and leave one subject out method is r2 = 0.930 and MSE = 0.013. The proposed linear EEG-ECD model can achieve 87.5% and 70.0% accuracy for male and female subjects, respectively, for a driver drowsiness application, percentage eyelid closure over the pupil over time (PERCLOS). This new ECD estimation method not only addresses the video-based method drawbacks, but also makes ECD estimation more computationally efficient and easier to implement in EEG sensors in a real time way. PMID:25237899

Li, Gang; Chung, Wan-Young

2014-01-01

174

EEG profile of litoxetine after single and repeated administration in healthy volunteers.  

PubMed Central

1. Litoxetine is a selective serotonin reuptake inhibitor with antidepressant activity in animal models and in depressed patients. 2. This double-blind, cross-over, placebo-controlled study was carried out in 12 healthy young male volunteers. The aim was to assess the EEG profile of litoxetine in parallel with its pharmacokinetics after a single dose or multiple administrations for 4 days (6 doses) of two dosages (10 mg and 25 mg). Spectral analysis of four EEG leads (F4-T4, F3-T3, T4-02 and T3-01) was done up to 12 h post-dose. 3. In single or multiple doses, litoxetine induced EEG changes characterised by a dose-related increase in fast beta energies, mainly beta 2, without any changes in slow waves (delta and theta). A slight reduction in alpha activity occurred only after repeated doses. 4. EEG changes occurred after a single oral administration and lasted at least 12 h with litoxetine blood concentrations ranging from 4 to 10 ng ml-1. With repeated administrations, the pharmacodynamic steady-state was achieved as the increase in beta 2 energies was the same before and 12 h post-dose. These effects occurred with litoxetine blood concentrations ranging from 3 to 7 ng ml-1 with the 10 mg dosage and from 8 to 18 ng ml-1 with the 25 mg dosage. The EEG profile did not change after 4 days of repeated administration, indicating that tolerance did not develop. 5. Cmax and AUC showed proportionality between the administered dosages of 10 and 25 mg.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8186061

Patat, A; Trocherie, S; Thébault, J J; Rosenzweig, P; Dubruc, C; Bianchetti, G; Morselli, P L; Court, L A

1994-01-01

175

Spectral modulation of frontal EEG during motor skill acquisition: a mobile EEG study.  

PubMed

This study investigates the modulation of frontal EEG dynamics with respect to progress in motor skill acquisition using a wireless EEG system with a single dry sensor. Participants were required to complete repeated trials of a computerized visual-motor task similar to mirror drawing while the EEG was collected. In each trial, task performance of the participants was summarized with a familiarity index which took into account the performance accuracy, completion rate and time. Our findings demonstrated that certain EEG power spectra decreased with an increase in motor task familiarity. In particular, frontal EEG activities in delta and theta bands of the whole trial and in gamma band in the middle of the trial are having a significant negative relationship with the overall familiarity level of the task. The findings suggest that frontal EEG spectra are significantly modulated during motor skill acquisition. Results of this study shed light on the possibility of simultaneous monitoring of brain activity during an unconstrained natural task with a single dry sensor mobile EEG in an everyday environment. PMID:24095979

Wong, Savio W H; Chan, Rosa H M; Mak, Joseph N

2014-01-01

176

Effect of immobilization on the EEG of the baboon. Comparison with telemetry results from unrestricted animals  

NASA Technical Reports Server (NTRS)

The EEG of the baboon was studied under two very different sets of conditions: 37 were totally immobolized while 12 were studied in their free movements with 4 channel telemetry. For the immobilzed, 3 stages were described: (1) activation, record desynchronized; (2) rest with 13-15 cm/sec rhythm, like the human alpha rhythm stage but with eyes open or closed; (3)relaxation with a decrease in 13-15 rhythm and the appearance of 5-7 cm/sec theta waves, eyelids closed, animal apparently sleeping. For the free animals the rest stage appeared when the animal's attention was not directed anywhere and there was no relaxation stage. It is concluded that the EEG pattern of the immobilized animal that was described as the "relaxation" stage really represents a special functional state which one must distinguish clearly from the physiological stages of sleep.

Bert, J.; Collomb, H.

1980-01-01

177

Temporal dynamics of sensorimotor integration in speech perception and production: independent component analysis of EEG data  

PubMed Central

Activity in anterior sensorimotor regions is found in speech production and some perception tasks. Yet, how sensorimotor integration supports these functions is unclear due to a lack of data examining the timing of activity from these regions. Beta (~20 Hz) and alpha (~10 Hz) spectral power within the EEG ? rhythm are considered indices of motor and somatosensory activity, respectively. In the current study, perception conditions required discrimination (same/different) of syllables pairs (/ba/ and /da/) in quiet and noisy conditions. Production conditions required covert and overt syllable productions and overt word production. Independent component analysis was performed on EEG data obtained during these conditions to (1) identify clusters of ? components common to all conditions and (2) examine real-time event-related spectral perturbations (ERSP) within alpha and beta bands. 17 and 15 out of 20 participants produced left and right ?-components, respectively, localized to precentral gyri. Discrimination conditions were characterized by significant (pFDR < 0.05) early alpha event-related synchronization (ERS) prior to and during stimulus presentation and later alpha event-related desynchronization (ERD) following stimulus offset. Beta ERD began early and gained strength across time. Differences were found between quiet and noisy discrimination conditions. Both overt syllable and word productions yielded similar alpha/beta ERD that began prior to production and was strongest during muscle activity. Findings during covert production were weaker than during overt production. One explanation for these findings is that ?-beta ERD indexes early predictive coding (e.g., internal modeling) and/or overt and covert attentional/motor processes. ?-alpha ERS may index inhibitory input to the premotor cortex from sensory regions prior to and during discrimination, while ?-alpha ERD may index sensory feedback during speech rehearsal and production. PMID:25071633

Jenson, David; Bowers, Andrew L.; Harkrider, Ashley W.; Thornton, David; Cuellar, Megan; Saltuklaroglu, Tim

2014-01-01

178

[Gender differences in EEG coherence changes during figural creative thinking: the efficacy coupling].  

PubMed

The study was aimed to explore the features of interaction between cortical areas during figural creative task performance in high- and low-creative men and women. We divided the participants into two groups with high and low creativity by the median of originality score. EEG was recorded at rest and during task performance (Torrance Tests of Creative Thinking "Incomplete figures"). The EEG coherence was computed in six frequency bands from theta1 to beta2. We analyzed the total values of coherence for each of 16 sites, calculated separately for intrahemispheric and interhemispheric connections. In the theta2, alphal, and alpha2 bands, coherence values decreased in task performance as compared to baseline in subjects with lower originality scores, whereas in subjects with higher scores, they increased in the theta2 and alpha1 bands. The decrease in the alpha2 band in the higher-creativity group was significantly lower in comparison with the decrease in the lower-score group. In the alpha2 band, the interaction of gender, creativity, laterality, and electrode position factors was also found during analysis of task-induced coherence changes. Further examination of the interaction showed the similarity of EEG coherence patterns in men and women with opposite creative abilities and higher values of task-induced coherence changes in the anterior regions of the left hemisphere and posterior regions of the right hemisphere in high-creative in comparison with low-creative men. The findings are discussed in terms of different cognitive strategies used by men and women that may have the same results in creative problem solving. PMID:19795805

Vol'f, N V; Tarasova, I V; Razumnikova, O M

2009-01-01

179

Chronic activation of peroxisome proliferator-activated receptor-alpha with fenofibrate prevents alterations in cardiac metabolic phenotype without changing the onset of decompensation in pacing-induced heart failure  

Technology Transfer Automated Retrieval System (TEKTRAN)

Severe heart failure (HF) is characterized by profound alterations in cardiac metabolic phenotype, with down-regulation of the free fatty acid (FFA) oxidative pathway and marked increase in glucose oxidation. We tested whether fenofibrate, a pharmacological agonist of peroxisome proliferator-activat...

180

EEG synchrony analysis for early diagnosis of Alzheimer's disease: A several synchrony measures and EEG data sets  

E-print Network

It has frequently been reported in the medical literature that the EEG of Alzheimer disease (AD) patients is less synchronous than in healthy subjects. In this paper, it is explored whether loss in EEG synchrony can be ...

Dauwels, Justin H. G.

181

Developmental Quantitative EEG Differences during Psychomotor Response to Music.  

ERIC Educational Resources Information Center

This study examined the electrophysiological differences between baseline EEG frequencies and EEG frequencies obtained during a psychomotor response to musical stimuli. Subjects were 9 children, with mean age of 5.2 years old. Electrophysiological differences between two different musical conditions were also compared. EEG was recorded during 3…

Flohr, John W.; Miller, Daniel C.

182

Automated EEG feature selection for brain computer interfaces  

Microsoft Academic Search

A brain computer interface (BCI) utilizes signals derived from electroencephalography (EEG) to establish a connection between a person's state of mind and a computer based signal processing system that interprets the EEG signals. The choice of suitable features of the available EEG signals is crucial for good BCI communication. The optimal set of features is strongly dependent on the subjects

Michael Schroder; Martin Bogdan; T. Hinterberger; N. Birbaumer

2003-01-01

183

Real time workload classification from an ambulatory wireless EEG system using hybrid EEG electrodes.  

PubMed

This paper describes a compact, lightweight and ultra-low power ambulatory wireless EEG system based upon QUASAR's innovative noninvasive bioelectric sensor technologies. The sensors operate through hair without skin preparation or conductive gels. Mechanical isolation built into the harness permits the recording of high quality EEG data during ambulation. Advanced algorithms developed for this system permit real time classification of workload during subject motion. Measurements made using the EEG system during ambulation are presented, including results for real time classification of subject workload. PMID:19164053

Matthews, R; Turner, P J; McDonald, N J; Ermolaev, K; Manus, T; Shelby, R A; Steindorf, M

2008-01-01

184

EEG correlates of fatigue during administration of a neuropsychological test battery  

PubMed Central

Objective Mental fatigue, a poorly understood symptom of sports-related concussion, ideally requires assessment across multiple modalities. Our study aimed to examine mental fatigue effects among ten neurologically normal, athletically active students undergoing typical concussion testing. It is our intention to ultimately address the question whether fatigue effects due to mild traumatic brain injury (mTBI) may become confounded with fatigue effects due to testing effort. Methods Fourteen athletically active and neurologically normal volunteers were initially recruited from Penn State University. Self-reported fatigue, neuropsychological performance, and electroencephalographic (EEG) activity were measured throughout the whole testing duration. EEG measures in frequency domain (e.g., relative power of theta, alpha & beta bands) were examined over the course of neuropsychological (NP) test administration. Results Predicted fatigue effects over the course of testing included: (a) increased self-reported fatigue; (b) increased errors on the Stroop Interference Test; (c) significantly increased relative power of theta activity during the Stroop Interference Test in frontal-central and parietal regions; and (d) migration of alpha activation from the occipital to anterior (left parietal and pre-central) regions during the Stroop Interference task administered at the beginning compared with the end of testing. Conclusions Results supported predictions related to subjective fatigue and cognitive performance and offered partial support for predictions related to EEG activation patterns over the course of administering the NP testing. Significance Neurologically intact and athletically active college students demonstrate effects related to fatigue after undergoing a typical sports concussion assessment battery, including an increase in subjectively experienced fatigue, a decrease in cognitive task performance accuracy and associated modulations in EEG activity. This finding should be considered by clinical practitioners while evaluating the symptoms of concussion and making a decision regarding the return-to-sport participation. PMID:21798799

Barwick, Fiona; Arnett, Peter; Slobounov, Semyon

2011-01-01

185

Inter-hemispheric EEG coherence analysis in Parkinson's disease: Assessing brain activity during emotion processing.  

PubMed

Parkinson's disease (PD) is not only characterized by its prominent motor symptoms but also associated with disturbances in cognitive and emotional functioning. The objective of the present study was to investigate the influence of emotion processing on inter-hemispheric electroencephalography (EEG) coherence in PD. Multimodal emotional stimuli (happiness, sadness, fear, anger, surprise, and disgust) were presented to 20 PD patients and 30 age-, education level-, and gender-matched healthy controls (HC) while EEG was recorded. Inter-hemispheric coherence was computed from seven homologous EEG electrode pairs (AF3-AF4, F7-F8, F3-F4, FC5-FC6, T7-T8, P7-P8, and O1-O2) for delta, theta, alpha, beta, and gamma frequency bands. In addition, subjective ratings were obtained for a representative of emotional stimuli. Interhemispherically, PD patients showed significantly lower coherence in theta, alpha, beta, and gamma frequency bands than HC during emotion processing. No significant changes were found in the delta frequency band coherence. We also found that PD patients were more impaired in recognizing negative emotions (sadness, fear, anger, and disgust) than relatively positive emotions (happiness and surprise). Behaviorally, PD patients did not show impairment in emotion recognition as measured by subjective ratings. These findings suggest that PD patients may have an impairment of inter-hemispheric functional connectivity (i.e., a decline in cortical connectivity) during emotion processing. This study may increase the awareness of EEG emotional response studies in clinical practice to uncover potential neurophysiologic abnormalities. PMID:24894699

Yuvaraj, R; Murugappan, M; Ibrahim, Norlinah Mohamed; Sundaraj, Kenneth; Omar, Mohd Iqbal; Mohamad, Khairiyah; Palaniappan, R; Satiyan, M

2015-02-01

186

EEG classification by learning vector quantization.  

PubMed

EEG classification using Learning Vector Quantization (LVQ) is introduced on the basis of a Brain-Computer Interface (BCI) built in Graz, where a subject controlled a cursor in one dimension on a monitor using potentials recorded from the intact scalp. The method of classification with LVQ is described in detail along with first results on a subject who participated in four on-line cursor control sessions. Using this data, extensive off-line experiments were performed to show the influence of the various parameters of the classifier and the extracted features of the EEG on the classification results. PMID:1286147

Flotzinger, D; Kalcher, J; Pfurtscheller, G

1992-12-01

187

The processing and transmission of EEG data  

NASA Technical Reports Server (NTRS)

Interest in sleep research was stimulated by the discovery of a number of physiological changes that occur during sleep and by the observed effects of sleep on physical and mental performance and status. The use of the relatively new methods of EEG measurement, transmission, and automatic scoring makes sleep analysis and categorization feasible. Sleep research involving the use of the EEG as a fundamental input has the potential of answering many unanswered questions involving physical and mental behavior, drug effects, circadian rhythm, and anesthesia.

Schulze, A. E.

1974-01-01

188

Modification of EEG functional connectivity and EEG power spectra in overweight and obese patients with food addiction: An eLORETA study.  

PubMed

We evaluated the modifications of electroencephalographic (EEG) power spectra and EEG connectivity in overweight and obese patients with elevated food addiction (FA) symptoms. Fourteen overweight and obese patients (3 men and 11 women) with three or more FA symptoms and fourteen overweight and obese patients (3 men and 11 women) with two or less FA symptoms were included in the study. EEG was recorded during three different conditions: 1) five minutes resting state (RS), 2) five minutes resting state after a single taste of a chocolate milkshake (ML-RS), and 3) five minutes resting state after a single taste of control neutral solution (N-RS). EEG analyses were conducted by means of the exact Low Resolution Electric Tomography software (eLORETA). Significant modification was observed only in the ML-RS condition. Compared to controls, patients with three or more FA symptoms showed an increase of delta power in the right middle frontal gyrus (Brodmann Area [BA] 8) and in the right precentral gyrus (BA 9), and theta power in the right insula (BA 13) and in the right inferior frontal gyrus (BA 47). Furthermore, compared to controls, patients with three or more FA symptoms showed an increase of functional connectivity in fronto-parietal areas in both the theta and alpha band. The increase of functional connectivity was also positively associated with the number of FA symptoms. Taken together, our results show that FA has similar neurophysiological correlates of other forms of substance-related and addictive disorders suggesting similar psychopathological mechanisms. PMID:25332109

Imperatori, Claudio; Fabbricatore, Mariantonietta; Innamorati, Marco; Farina, Benedetto; Quintiliani, Maria Isabella; Lamis, Dorian A; Mazzucchi, Edoardo; Contardi, Anna; Vollono, Catello; Della Marca, Giacomo

2014-10-21

189

Oligoclonal repertoire of the CD8 alpha alpha and the CD8 alpha beta TCR-alpha/beta murine intestinal intraepithelial T lymphocytes: evidence for the random emergence of T cells  

PubMed Central

The epithelium of the small intestine in normal euthymic mice contains a large number of intraepithelial lymphocytes (IEL), some of which bear a T cell receptor alpha/beta (TCR-alpha/beta). About half of these TCR- alpha/beta IEL display the CD8 alpha alpha phenotype and the remaining have the CD8 alpha beta or the CD4 phenotypes. To examine whether TCR- alpha/beta IEL have a TCR-beta chain repertoire as diverse as that of TCR-alpha/beta lymph node lymphocytes (LNL), we used a recently described PCR technique that allows a global analysis of the TCR-beta chain repertoire. Within any given mouse, the repertoires expressed in both CD8 alpha alpha and CD8 alpha beta TCR-alpha/beta IEL populations are oligoclonal and nonoverlapping between the two subsets. The clones are largely conserved through the length of the small intestine of the same individual. However, genetically identical individuals raised under indistinguishable environmental conditions display distinct oligoclonal repertoires. Those findings indicate that few cells of CD8 alpha alpha or of the CD8 alpha beta phenotype are responsible for the repopulation of the intestinal epithelium. PMID:7931068

1994-01-01

190

Transcranial direct current stimulation and power spectral parameters: a tDCS/EEG co-registration study  

PubMed Central

Transcranial direct current stimulation (tDCS) delivers low electric currents to the brain through the scalp. Constant electric currents induce shifts in neuronal membrane excitability, resulting in secondary changes in cortical activity. Concomitant electroencephalography (EEG) monitoring during tDCS can provide valuable information on the tDCS mechanisms of action. This study examined the effects of anodal tDCS on spontaneous cortical activity in a resting brain to disclose possible modulation of spontaneous oscillatory brain activity. EEG activity was measured in ten healthy subjects during and after a session of anodal stimulation of the postero-parietal cortex to detect the tDCS-induced alterations. Changes in the theta, alpha, beta, and gamma power bands were investigated. Three main findings emerged: (1) an increase in theta band activity during the first minutes of stimulation; (2) an increase in alpha and beta power during and after stimulation; (3) a widespread activation in several brain regions. PMID:25147519

Mangia, Anna L.; Pirini, Marco; Cappello, Angelo

2014-01-01

191

Automatic sleep onset detection using single EEG sensor.  

PubMed

Sleep has been shown to be imperative for the health and well-being of an individual. To design intelligent sleep management tools, such as the music-induce sleep-aid device, automatic detection of sleep onset is critical. In this work, we propose a simple yet accurate method for sleep onset prediction, which merely relies on Electroencephalogram (EEG) signal acquired from a single frontal electrode in a wireless headband. The proposed method first extracts energy power ratio of theta (4-8Hz) and alpha (8-12Hz) bands along a 3-second shifting window, then calculates the slow wave of each frequency band along the time domain. The resulting slow waves are then fed to a rule-based engine for sleep onset detection. To evaluate the effectiveness of the approach, polysomnographic (PSG) and headband EEG signals were obtained from 20 healthy adults, each of which underwent 2 sessions of sleep events. In total, data from 40 sleep events were collected. Each recording was then analyzed offline by a PSG technologist via visual observation of PSG waveforms, who annotated sleep stages N1 and N2 by using the American Academy of Sleep Medicine (AASM) scoring rules. Using this as the gold standard, our approach achieved a 87.5% accuracy for sleep onset detection. The result is better or at least comparable to the other state of the art methods which use either multi-or single- channel based data. The approach has laid down the foundations for our future work on developing intelligent sleep aid devices. PMID:25570439

Zhuo Zhang; Cuntai Guan; Ti Eu Chan; Juanhong Yu; Ng, Andrew Keong; Haihong Zhang; Chee Keong Kwoh

2014-08-01

192

EEG Power During Waking and NREM Sleep in Primary Insomnia  

PubMed Central

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

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

2013-01-01

193

Phase synchrony analysis of EEG during music perception reveals changes in functional connectivity due to musical expertise  

Microsoft Academic Search

Differences in functional and topographical connectivity patterns between two groups, musicians and non-musicians, during attentively listening to three different pieces of music and to a text of neutral content, were presented by means of EEG phase synchrony analysis in five standard frequency bands: delta (o4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), and gamma (430 Hz). The

Joydeep Bhattacharya; Hellmuth Petsche

194

The Role of Epilepsy and Epileptiform EEGs in Autism Spectrum Disorders  

PubMed Central

Autism is a neurodevelopmental disorder of unknown etiology characterized by social and communication deficits and the presence of restricted interests/repetitive behaviors. Higher rates of epilepsy have long been reported, but prevalence estimates vary from as little as 5% to as much as 46%. This variation is probably the result of sample characteristics that increase epilepsy risk such as sample ascertainment, lower IQ, the inclusion of patients with non-idiopathic autism, age, and gender. However, critical review of the literature reveals that the rate in idiopathic cases with normal IQ is still significantly above the population risk suggesting that autism itself is associated with an increased risk of epilepsy. Recently there has been interest in the occurrence of epileptiform electroencephalograms (EEGs) even in the absence of epilepsy. Rates as high as 60% have been reported and some investigators propose that these abnormalities may play a causal role in the autism phenotype. While this phenomenon is still not well understood and risk factors have yet to be determined, the treatment implications are increasingly important. We review the recent literature to elucidate possible risk factors for both epilepsy and epileptiform EEGs. We then review existing data and discuss controversies surrounding treatment of EEG abnormalities. PMID:19454962

Spence, Sarah J; Schneider, Mark T

2009-01-01

195

Separation and reconstruction of BCG and EEG signals during continuous EEG and fMRI recordings  

PubMed Central

Despite considerable effort to remove it, the ballistocardiogram (BCG) remains a major artifact in electroencephalographic data (EEG) acquired inside magnetic resonance imaging (MRI) scanners, particularly in continuous (as opposed to event-related) recordings. In this study, we have developed a new Direct Recording Prior Encoding (DRPE) method to extract and separate the BCG and EEG components from contaminated signals, and have demonstrated its performance by comparing it quantitatively to the popular Optimal Basis Set (OBS) method. Our modified recording configuration allows us to obtain representative bases of the BCG- and EEG-only signals. Further, we have developed an optimization-based reconstruction approach to maximally incorporate prior knowledge of the BCG/EEG subspaces, and of the signal characteristics within them. Both OBS and DRPE methods were tested with experimental data, and compared quantitatively using cross-validation. In the challenging continuous EEG studies, DRPE outperforms the OBS method by nearly sevenfold in separating the continuous BCG and EEG signals. PMID:25002836

Xia, Hongjing; Ruan, Dan; Cohen, Mark S.

2014-01-01

196

Use of electroencephalography (EEG) to assess CNS changes produced by pesticides with different modes of action: Effects of permethrin, deltamethrin, fipronil, imidacloprid, carbaryl, and triadimefon.  

PubMed

The electroencephalogram (EEG) is an apical measure, capable of detecting changes in brain neuronal activity produced by internal or external stimuli. We assessed whether pesticides with different modes of action produced different changes in the EEG of adult male Long-Evans rats. The EEG was recorded using two montages (visual cortex referenced to the cerebellum and to the frontal cortex) in unrestrained rats at the time of peak behavioral effects. Pesticides included: permethrin and deltamethrin (Type I and Type II pyrethroids; 2h), fipronil (single and repeated doses; phenylpyrazole; 6h), imidacloprid (neonicotinoid; 2h), carbaryl (carbamate; 0.5h), and triadimefon (triazole; 1h), using dosages that produced approximately an ED30 or an ED50-ED80 change in motor activity. Permethrin (43, 100mg/kg) increased amplitudes or areas (delta, alpha, or gamma bands) in the EEG. Deltamethrin (2.5, 5.5mg/kg) reduced the amplitudes or areas of the delta, theta, alpha, beta, and gamma bands, but the changes were not dose-related. A single treatment with fipronil (25, 50mg/kg, but not 5, 10mg/kg) decreased gamma band area. Additional changes in the delta, theta, and gamma bands were observed when fipronil (5, 10mg/kg) was administered for 14days. Imidacloprid (50, 100mg/kg) did not alter the EEG. Carbaryl (10, 50mg/kg) decreased theta area, and decreased delta and increased beta frequency. Triadimefon (75, 150mg/kg) produced minimal changes in the EEG. The results show that the EEG is affected differently by approximately equipotent doses of pesticides with different modes of action. PMID:25481984

Freeborn, Danielle L; McDaniel, Katherine L; Moser, Virginia C; Herr, David W

2015-01-15

197

Spontaneous EEG activity and spontaneous emotion regulation.  

PubMed

Variability in both frontal and parietal spontaneous EEG activity, using ? and ? band power and ?/? and ?/? ratios, was explored in a sample of 96 healthy volunteers as a potential correlate of individual differences in spontaneous emotion regulation (SER). Following a baseline EEG recording, participants were asked to continuously rate their discomfort while looking at affective pictures, as well as for a period of time after exposure. Greater spontaneous ? band power in parietal locations, lower frontal and parietal ?/? ratios, and lower parietal ?/? ratio were associated with lower ratings of discomfort after the offset of unpleasant pictures. Moreover, lower parietal ?/? ratio was also related to less time needed to recover from discomfort after exposure to aversive pictures, while only a greater frontal and parietal ? band power appeared to be associated with faster recovery from discomfort induced by normative-neutral pictures. However, parietal ?/? ratio was the only predictor of both minimum discomfort ratings and time needed to downregulate following exposure to unpleasant pictures, and frontal ? band power the only spontaneous EEG index that predicted variability in spontaneous down-regulation after the exposure to normative-neutral pictures. Results are discussed focusing on the utility of diverse spontaneous EEG measures in several cortical regions when capturing trait-like individual differences in emotion regulation capabilities and processes. PMID:25219892

Tortella-Feliu, M; Morillas-Romero, A; Balle, M; Llabrés, J; Bornas, X; Putman, P

2014-12-01

198

Illumination influences working memory: an EEG study.  

PubMed

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. PMID:23694704

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

2013-09-01

199

Optimizing microsurgical skills with EEG neurofeedback  

Microsoft Academic Search

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)

Tomas Ros; Merrick J Moseley; Philip A Bloom; Larry Benjamin; Lesley A Parkinson; John H Gruzelier

2009-01-01

200

Music Shifts Frontal EEG in Depressed Adolescents.  

ERIC Educational Resources Information Center

Fourteen chronically depressed female adolescents listened to rock music for a 23-minute session. EEG was recorded and saliva samples were collected to determine the effects of the music on stress hormone cortisol levels. No differences were reported for mood state; however, cortisol levels decreased and relative right-frontal activation was…

Field, Tiffany; Martinez, Alex; Nawrocki, Thomas; Pickens, Jeffrey; Fox, Nathan A.; Schanberg, Saul

1998-01-01

201

Alpha-Theta Effects Associated with Ageing during the Stroop Test  

PubMed Central

The Stroop effect is considered as a standard attentional measure to study conflict resolution in humans. The response of the brain to conflict is supposed to change over time and it is impaired in certain pathological conditions. Neuropsychological Stroop test measures have been complemented with electroencephalography (EEG) techniques to evaluate the mechanisms in the brain that underlie conflict resolution from the age of 20 to 70. To study the changes in EEG activity during life, we recruited a large sample of healthy subjects of different ages that included 90 healthy individuals, divided by age into decade intervals, which performed the Stroop test while recording a 14 channel EEG. The results highlighted an interaction between age and stimulus that was focused on the prefrontal (Alpha and Theta band) and Occipital (Alpha band) areas. We concluded that behavioural Stroop interference is directly influenced by opposing Alpha and Theta activity and evolves across the decades of life. PMID:24867024

Nombela, Cristina; Nombela, Manuel; Castell, Pedro; García, Teodoro; López-Coronado, Juan; Herrero, María Trinidad

2014-01-01

202

Simultaneous EEG-fMRI brain signatures of auditory cue utilization  

PubMed Central

Optimal utilization of acoustic cues during auditory categorization is a vital skill, particularly when informative cues become occluded or degraded. Consequently, the acoustic environment requires flexible choosing and switching amongst available cues. The present study targets the brain functions underlying such changes in cue utilization. Participants performed a categorization task with immediate feedback on acoustic stimuli from two categories that varied in duration and spectral properties, while we simultaneously recorded Blood Oxygenation Level Dependent (BOLD) responses in fMRI and electroencephalograms (EEGs). In the first half of the experiment, categories could be best discriminated by spectral properties. Halfway through the experiment, spectral degradation rendered the stimulus duration the more informative cue. Behaviorally, degradation decreased the likelihood of utilizing spectral cues. Spectrally degrading the acoustic signal led to increased alpha power compared to nondegraded stimuli. The EEG-informed fMRI analyses revealed that alpha power correlated with BOLD changes in inferior parietal cortex and right posterior superior temporal gyrus (including planum temporale). In both areas, spectral degradation led to a weaker coupling of BOLD response to behavioral utilization of the spectral cue. These data provide converging evidence from behavioral modeling, electrophysiology, and hemodynamics that (a) increased alpha power mediates the inhibition of uninformative (here spectral) stimulus features, and that (b) the parietal attention network supports optimal cue utilization in auditory categorization. The results highlight the complex cortical processing of auditory categorization under realistic listening challenges. PMID:24926232

Scharinger, Mathias; Herrmann, Björn; Nierhaus, Till; Obleser, Jonas

2014-01-01

203

Analysis of EEG activity in response to binaural beats with different frequencies.  

PubMed

When two coherent sounds with nearly similar frequencies are presented to each ear respectively with stereo headphones, the brain integrates the two signals and produces a sensation of a third sound called binaural beat (BB). Although earlier studies showed that BB could influence behavior and cognition, common agreement on the mechanism of BB has not been reached yet. In this work, we employed Relative Power (RP), Phase Locking Value (PLV) and Cross-Mutual Information (CMI) to track EEG changes during BB stimulations. EEG signals were acquired from 13 healthy subjects. Five-minute BBs with four different frequencies were tested: delta band (1 Hz), theta band (5 Hz), alpha band (10 Hz) and beta band (20 Hz). We observed RP increase in theta and alpha bands and decrease in beta band during delta and alpha BB stimulations. RP decreased in beta band during theta BB, while RP decreased in theta band during beta BB. However, no clear brainwave entrainment effect was identified. Connectivity changes were detected following the variation of RP during BB stimulations. Our observation supports the hypothesis that BBs could affect functional brain connectivity, suggesting that the mechanism of BB-brain interaction is worth further study. PMID:25448376

Gao, Xiang; Cao, Hongbao; Ming, Dong; Qi, Hongzhi; Wang, Xuemin; Wang, Xiaolu; Chen, Runge; Zhou, Peng

2014-12-01

204

Modulation of EEG Functional Connectivity Networks in Subjects Undergoing Repetitive Transcranial Magnetic Stimulation  

PubMed Central

Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique that utilizes magnetic fluxes to alter cortical activity. Continuous theta-burst repetitive TMS (cTBS) results in long-lasting decreases in indices of cortical excitability, and alterations in performance of behavioral tasks. We investigated the effects of cTBS on cortical function via functional connectivity and graph theoretical analysis of EEG data. Thirty-one channel resting-state EEG recordings were obtained before and after 40 s of cTBS stimulation to the left primary motor cortex. Functional connectivity between nodes was assessed in multiple frequency bands using lagged max-covariance, and subsequently thresholded to construct undirected graphs. After cTBS, we find widespread decreases in functional connectivity in the alpha band. There are also simultaneous increases in functional connectivity in the high-beta bands, especially amongst anterior and interhemispheric connections. The analysis of the undirected graphs reveals that interhemispheric and interregional connections are more likely to be modulated after cTBS than local connections. There is also a shift in the topology of network connectivity, with an increase in the clustering coefficient after cTBS in the beta bands, and a decrease in clustering and increase in path length in the alpha band, with the alpha-band connectivity primarily decreased near the site of stimulation. cTBS produces widespread alterations in cortical functional connectivity, with resulting shifts in cortical network topology. PMID:23471637

Shafi, Mouhsin M.; Westover, M. Brandon; Oberman, Lindsay; Cash, Sydney S.; Pascual-Leone, Alvaro

2014-01-01

205

Zazen meditation and no-task resting EEG compared with LORETA intracortical source localization.  

PubMed

Meditation is a self-induced and willfully initiated practice that alters the state of consciousness. The meditation practice of Zazen, like many other meditation practices, aims at disregarding intrusive thoughts while controlling body posture. It is an open monitoring meditation characterized by detached moment-to-moment awareness and reduced conceptual thinking and self-reference. Which brain areas differ in electric activity during Zazen compared to task-free resting? Since scalp electroencephalography (EEG) waveforms are reference-dependent, conclusions about the localization of active brain areas are ambiguous. Computing intracerebral source models from the scalp EEG data solves this problem. In the present study, we applied source modeling using low resolution brain electromagnetic tomography (LORETA) to 58-channel scalp EEG data recorded from 15 experienced Zen meditators during Zazen and no-task resting. Zazen compared to no-task resting showed increased alpha-1 and alpha-2 frequency activity in an exclusively right-lateralized cluster extending from prefrontal areas including the insula to parts of the somatosensory and motor cortices and temporal areas. Zazen also showed decreased alpha and beta-2 activity in the left angular gyrus and decreased beta-1 and beta-2 activity in a large bilateral posterior cluster comprising the visual cortex, the posterior cingulate cortex and the parietal cortex. The results include parts of the default mode network and suggest enhanced automatic memory and emotion processing, reduced conceptual thinking and self-reference on a less judgmental, i.e., more detached moment-to-moment basis during Zazen compared to no-task resting. PMID:25284209

Faber, Pascal L; Lehmann, Dietrich; Gianotti, Lorena R R; Milz, Patricia; Pascual-Marqui, Roberto D; Held, Marlene; Kochi, Kieko

2015-02-01

206

'Time-scribe': a universal time writer for any EEG/polygraph chart recorder.  

PubMed

An ubiquitous digital clock 'time-scribe' with a unique pen-galvanometer writer section has been described which should greatly improve the correlation of a long term EEG with any other time related event or medium. The output of the clock generates on any pen-galvanometer based chart recorder numerical and some alpha characters which are easily and immediately readable. Because of its convenience, simplicity and basic practical application it should also stimulate discussion for the unification of time write-out standards and methods. PMID:6200303

Ives, J

1984-04-01

207

Simultaneous EEG and EDA measures in adolescent attention deficit hyperactivity disorder.  

PubMed

Adolescent unmedicated ADHD males and age- and sex-matched normal control subjects were examined simultaneously using EEG and EDA measures in a resting eyes-open condition. ADHD adolescents showed increased absolute and relative Theta and Alpha1 activity, reduced relative Beta activity, reduced skin conductance level (SCL) and a reduced number of non-specific skin conductance responses (NS.SCRs) compared with the control subjects. Our findings indicate the continuation of increased slow wave activity in ADHD adolescents and the presence of a state of autonomic hypoarousal in this clinical group. PMID:10576397

Lazzaro, I; Gordon, E; Li, W; Lim, C L; Plahn, M; Whitmont, S; Clarke, S; Barry, R J; Dosen, A; Meares, R

1999-11-01

208

The EEG Correlates of the TMS Induced EMG Silent Period in Humans  

PubMed Central

Application of magnetic or electrical stimulation to the motor cortex can result in a period of electromyography (EMG) silence in a tonically active peripheral muscle. This period of EMG silence is referred to as the silent period (SP). The duration of SP shows intersubject variability and reflects the integrity of cortical and corticospinal pathways. A non-invasive technique for assessing the duration of SP is the combination of Transcranial Magnetic Stimulation (TMS) with EMG. Utilizing TMS-EMG, several studies have reported on the shortening or lengthening of SP in neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, obsessive compulsive disorder, epilepsy, Parkinson’s disease, and stroke. However, cortical, corticospinal and peripheral components are difficult to disentangle from EMG alone. Here, we use the multimodal neuroimaging technique of TMS-EMG combined with concurrent electroencephalography (EEG) recording to further examine the cortical origin of SP and the cortical oscillatory activity that underlies SP genesis. We demonstrate that the duration of SP is related to the temporal characteristics of the cortical reactivity and the power of delta to alpha oscillations in both local and remote areas ipsilateral and contralateral to the stimulation site, and beta oscillations locally. We illustrate that, compared to EMG, the EEG indices of the SP provide additional information about the brain dynamics and propose that the EEG measures of SP may be used in future clinical and research investigations to more precisely delineate the mechanisms underlying inhibitory impairments. PMID:23800790

Farzan, Faranak; Barr, Mera S.; Hoppenbrouwers, Sylco S.; Fitzgerald, Paul B.; Chen, Robert; Pascual-Leone, Alvaro; Daskalakis, Zafiris J.

2014-01-01

209

Mental fatigue and working memory load estimation: interaction and implications for EEG-based passive BCI.  

PubMed

Current mental state monitoring systems, a.k.a. passive brain-computer interfaces (pBCI), allow one to perform a real-time assessment of an operator's cognitive state. In EEG-based systems, typical measurements for workload level assessment are band power estimates in several frequency bands. Mental fatigue, arising from growing time-on-task (TOT), can significantly affect the distribution of these band power features. However, the impact of mental fatigue on workload (WKL) assessment has not yet been evaluated. With this paper we intend to help fill in this lack of knowledge by analyzing the influence of WKL and TOT on EEG band power features, as well as their interaction and its impact on classification performance. Twenty participants underwent an experiment that modulated both their WKL (low/high) and time spent on the task (short/long). Statistical analyses were performed on the EEG signals, behavioral and subjective data. They revealed opposite changes in alpha power distribution between WKL and TOT conditions, as well as a decrease in WKL level discriminability with increasing TOT in both number of statistical differences in band power and classification performance. Implications for pBCI systems and experimental protocol design are discussed. PMID:24111257

Roy, Raphaelle N; Bonnet, Stephane; Charbonnier, Sylvie; Campagne, Aurelie

2013-01-01

210

The EEG correlates of the TMS-induced EMG silent period in humans.  

PubMed

Application of magnetic or electrical stimulation to the motor cortex can result in a period of electromyography (EMG) silence in a tonically active peripheral muscle. This period of EMG silence is referred to as the silent period (SP). The duration of SP shows intersubject variability and reflects the integrity of cortical and corticospinal pathways. A non-invasive technique for assessing the duration of SP is the combination of Transcranial Magnetic Stimulation (TMS) with EMG. Utilizing TMS-EMG, several studies have reported on the shortening or lengthening of SP in neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, obsessive compulsive disorder, epilepsy, Parkinson's disease, and stroke. However, cortical, corticospinal and peripheral components are difficult to disentangle from EMG alone. Here, we use the multimodal neuroimaging technique of TMS-EMG combined with concurrent electroencephalography (EEG) recording to further examine the cortical origin of SP and the cortical oscillatory activity that underlies SP genesis. We demonstrate that the duration of SP is related to the temporal characteristics of the cortical reactivity and the power of delta to alpha oscillations in both local and remote areas ipsilateral and contralateral to the stimulation site, and beta oscillations locally. We illustrate that, compared to EMG, the EEG indices of the SP provide additional information about the brain dynamics and propose that the EEG measures of SP may be used in future clinical and research investigations to more precisely delineate the mechanisms underlying inhibitory impairments. PMID:23800790

Farzan, Faranak; Barr, Mera S; Hoppenbrouwers, Sylco S; Fitzgerald, Paul B; Chen, Robert; Pascual-Leone, Alvaro; Daskalakis, Zafiris J

2013-12-01

211

Association of autonomic nervous system and EEG scalp potential during playing 2D Grand Turismo 5.  

PubMed

Cerebral activation and autonomic nervous system have importance in studies such as mental stress. The aim of this study is to analyze variations in EEG scalp potential which may influence autonomic activation of heart while playing video games. Ten healthy participants were recruited in this study. Electroencephalogram (EEG) and electrocardiogram (ECG) signals were measured simultaneously during playing video game and rest conditions. Sympathetic and parasympathetic innervations of heart were evaluated from heart rate variability (HRV), derived from the ECG. Scalp potential was measured by the EEG. The results showed a significant upsurge in the value theta Fz/alpha Pz (p<0.001) while playing game. The results also showed tachycardia while playing video game as compared to rest condition (p<0.005). Normalized low frequency power and ratio of low frequency/high frequency power were significantly increased while playing video game and normalized high frequency power sank during video games. Results showed synchronized activity of cerebellum and sympathetic and parasympathetic innervation of heart. PMID:23366661

Subhani, Ahmad Rauf; Likun, Xia; Saeed Malik, Aamir

2012-01-01

212

Soft, Comfortable Polymer Dry Electrodes for High Quality ECG and EEG Recording.  

PubMed

Conventional gel electrodes are widely used for biopotential measurements, despite important drawbacks such as skin irritation, long set-up time and uncomfortable removal. Recently introduced dry electrodes with rigid metal pins overcome most of these problems; however, their rigidity causes discomfort and pain. This paper presents dry electrodes offering high user comfort, since they are fabricated from EPDM rubber containing various additives for optimum conductivity, flexibility and ease of fabrication. The electrode impedance is measured on phantoms and human skin. After optimization of the polymer composition, the skin-electrode impedance is only ~10 times larger than that of gel electrodes. Therefore, these electrodes are directly capable of recording strong biopotential signals such as ECG while for low-amplitude signals such as EEG, the electrodes need to be coupled with an active circuit. EEG recordings using active polymer electrodes connected to a clinical EEG system show very promising results: alpha waves can be clearly observed when subjects close their eyes, and correlation and coherence analyses reveal high similarity between dry and gel electrode signals. Moreover, all subjects reported that our polymer electrodes did not cause discomfort. Hence, the polymer-based dry electrodes are promising alternatives to either rigid dry electrodes or conventional gel electrodes. PMID:25513825

Chen, Yun-Hsuan; de Beeck, Maaike Op; Vanderheyden, Luc; Carrette, Evelien; Mihajlovi?, Vojkan; Vanstreels, Kris; Grundlehner, Bernard; Gadeyne, Stefanie; Boon, Paul; Van Hoof, Chris

2014-01-01

213

Soft, Comfortable Polymer Dry Electrodes for High Quality ECG and EEG Recording  

PubMed Central

Conventional gel electrodes are widely used for biopotential measurements, despite important drawbacks such as skin irritation, long set-up time and uncomfortable removal. Recently introduced dry electrodes with rigid metal pins overcome most of these problems; however, their rigidity causes discomfort and pain. This paper presents dry electrodes offering high user comfort, since they are fabricated from EPDM rubber containing various additives for optimum conductivity, flexibility and ease of fabrication. The electrode impedance is measured on phantoms and human skin. After optimization of the polymer composition, the skin-electrode impedance is only ?10 times larger than that of gel electrodes. Therefore, these electrodes are directly capable of recording strong biopotential signals such as ECG while for low-amplitude signals such as EEG, the electrodes need to be coupled with an active circuit. EEG recordings using active polymer electrodes connected to a clinical EEG system show very promising results: alpha waves can be clearly observed when subjects close their eyes, and correlation and coherence analyses reveal high similarity between dry and gel electrode signals. Moreover, all subjects reported that our polymer electrodes did not cause discomfort. Hence, the polymer-based dry electrodes are promising alternatives to either rigid dry electrodes or conventional gel electrodes. PMID:25513825

Chen, Yun-Hsuan; de Beeck, Maaike Op; Vanderheyden, Luc; Carrette, Evelien; Mihajlovi?, Vojkan; Vanstreels, Kris; Grundlehner, Bernard; Gadeyne, Stefanie; Boon, Paul; Van Hoof, Chris

2014-01-01

214

Epileptic EEG classification based on kernel sparse representation.  

PubMed

The automatic identification of epileptic EEG signals is significant in both relieving heavy workload of visual inspection of EEG recordings and treatment of epilepsy. This paper presents a novel method based on the theory of sparse representation to identify epileptic EEGs. At first, the raw EEG epochs are preprocessed via Gaussian low pass filtering and differential operation. Then, in the scheme of sparse representation based classification (SRC), a test EEG sample is sparsely represented on the training set by solving l1-minimization problem, and the represented residuals associated with ictal and interictal training samples are computed. The test EEG sample is categorized as the class that yields the minimum represented residual. So unlike the conventional EEG classification methods, the choice and calculation of EEG features are avoided in the proposed framework. Moreover, the kernel trick is employed to generate a kernel version of the SRC method for improving the separability between ictal and interictal classes. The satisfactory recognition accuracy of 98.63% for ictal and interictal EEG classification and for ictal and normal EEG classification has been achieved by the kernel SRC. In addition, the fast speed makes the kernel SRC suit for the real-time seizure monitoring application in the near future. PMID:24694170

Yuan, Qi; Zhou, Weidong; Yuan, Shasha; Li, Xueli; Wang, Jiwen; Jia, Guijuan

2014-06-01

215

Causality within the Epileptic Network: An EEG-fMRI Study Validated by Intracranial EEG  

PubMed Central

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 work-up. 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 Modeling (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 blood oxygenation level dependent (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 favored a model corresponding to the left dorso-lateral 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 “psycho-physiological interaction” analysis; (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. PMID:24294210

Vaudano, Anna Elisabetta; Avanzini, Pietro; Tassi, Laura; Ruggieri, Andrea; Cantalupo, Gaetano; Benuzzi, Francesca; Nichelli, Paolo; Lemieux, Louis; Meletti, Stefano

2013-01-01

216

Hidden pattern discovery on event related potential EEG signals.  

PubMed

EEG signals are important to capture brain disorders. They are useful for analyzing the cognitive activity of the brain and diagnosing types of seizure and potential mental health problems. The Event Related Potential can be measured through the EEG signal. However, it is always difficult to interpret due to its low amplitude and sensitivity to changes of the mental activity. In this paper, we propose a novel approach to incrementally detect the pattern of this kind of EEG signal. This approach successfully summarizes the whole stream of the EEG signal by finding the correlations across the electrodes and discriminates the signals corresponding to various tasks into different patterns. It is also able to detect the transition period between different EEG signals and identify the electrodes which contribute the most to these signals. The experimental results show that the proposed method allows the significant meaning of the EEG signal to be obtained from the extracted pattern. PMID:19505633

Ng, Kam Swee; Yang, Hyung-Jeong; Kim, Sun-Hee

2009-07-01

217

The cholinergic system, EEG and sleep.  

PubMed

Acetylcholine is a potent excitatory neurotransmitter, crucial for cognition and the control of alertness and arousal. Vigilance-specific recordings of the electroencephalogram (EEG) potently reflect thalamo-cortical and brainstem-cortical cholinergic activity that drives theta rhythms and task-specific cortical (de-synchronisation. Additionally, cholinergic projections from the basal forebrain act as a relay centre for the brainstem-cortical arousal system, but also directly modulate cortical activity, and thus promote wakefulness or rapid-eye movement (REM) sleep. Disease states such as sleep disorders, dementia and certain types of epilepsy are a further reflection of the potent cholinergic impact on CNS physiology and function, and highlight the relevance and inter-dependence of sleep and EEG. With novel technologies and computational tools now becoming available, advanced mechanistic insights may be gained and new avenues explored for diagnostics and therapeutics. PMID:21238497

Platt, Bettina; Riedel, Gernot

2011-08-10

218

Transfer Function between EEG and BOLD Signals of Epileptic Activity  

PubMed Central

Simultaneous electroencephalogram (EEG)-functional Magnetic Resonance Imaging (fMRI) recordings have seen growing application in the evaluation of epilepsy, namely in the characterization of brain networks related to epileptic activity. In EEG-correlated fMRI studies, epileptic events are usually described as boxcar signals based on the timing information retrieved from the EEG, and subsequently convolved with a hemodynamic response function to model the associated Blood Oxygen Level Dependent (BOLD) changes. Although more flexible approaches may allow a higher degree of complexity for the hemodynamics, the issue of how to model these dynamics based on the EEG remains an open question. In this work, a new methodology for the integration of simultaneous EEG-fMRI data in epilepsy is proposed, which incorporates a transfer function from the EEG to the BOLD signal. Independent component analysis of the EEG is performed, and a number of metrics expressing different models of the EEG-BOLD transfer function are extracted from the resulting time courses. These metrics are then used to predict the fMRI data and to identify brain areas associated with the EEG epileptic activity. The methodology was tested on both ictal and interictal EEG-fMRI recordings from one patient with a hypothalamic hamartoma. When compared to the conventional analysis approach, plausible, consistent, and more significant activations were obtained. Importantly, frequency-weighted EEG metrics yielded superior results than those weighted solely on the EEG power, which comes in agreement with previous literature. Reproducibility, specificity, and sensitivity should be addressed in an extended group of patients in order to further validate the proposed methodology and generalize the presented proof of concept. PMID:23355832

Leite, Marco; Leal, Alberto; Figueiredo, Patrícia

2013-01-01

219

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

PubMed

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. PMID:2798991

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

1989-02-01

220

Burst suppression in sleep in a routine outpatient EEG?  

PubMed Central

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.

Kheder, Ammar; Bianchi, Matt T.; Westover, M. Brandon

2014-01-01

221

A Discriminative Approach to EEG Seizure Detection  

PubMed Central

Seizures are abnormal sudden discharges in the brain with signatures represented in electroencephalograms (EEG). The efficacy of the application of speech processing techniques to discriminate between seizure and non-seizure states in EEGs is reported. The approach accounts for the challenges of unbalanced datasets (seizure and non-seizure), while also showing a system capable of real-time seizure detection. The Minimum Classification Error (MCE) algorithm, which is a discriminative learning algorithm with wide-use in speech processing, is applied and compared with conventional classification techniques that have already been applied to the discrimination between seizure and non-seizure states in the literature. The system is evaluated on 22 pediatric patients multi-channel EEG recordings. Experimental results show that the application of speech processing techniques and MCE compare favorably with conventional classification techniques in terms of classification performance, while requiring less computational overhead. The results strongly suggests the possibility of deploying the designed system at the bedside. PMID:22195192

Johnson, Ashley N.; Sow, Daby; Biem, Alain

2011-01-01

222

EEG and Neuronal Activity Topography analysis can predict effectiveness of shunt operation in idiopathic normal pressure hydrocephalus patients?  

PubMed Central

Idiopathic normal pressure hydrocephalus (iNPH) is a neuropsychiatric syndrome characterized by gait disturbance, cognitive impairment and urinary incontinence that affect elderly individuals. These symptoms can potentially be reversed by cerebrospinal fluid (CSF) drainage or shunt operation. Prior to shunt operation, drainage of a small amount of CSF or “CSF tapping” is usually performed to ascertain the effect of the operation. Unfortunately, conventional neuroimaging methods such as single photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI), as well as electroencephalogram (EEG) power analysis seem to have failed to detect the effect of CSF tapping on brain function. In this work, we propose the use of Neuronal Activity Topography (NAT) analysis, which calculates normalized power variance (NPV) of EEG waves, to detect cortical functional changes induced by CSF tapping in iNPH. Based on clinical improvement by CSF tapping and shunt operation, we classified 24 iNPH patients into responders (N = 11) and nonresponders (N = 13), and performed both EEG power analysis and NAT analysis. We also assessed correlations between changes in NPV and changes in functional scores on gait and cognition scales before and after CSF tapping. NAT analysis showed that after CSF tapping there was a significant decrease in alpha NPV at the medial frontal cortex (FC) (Fz) in responders, while nonresponders exhibited an increase in alpha NPV at the right dorsolateral prefrontal cortex (DLPFC) (F8). Furthermore, we found correlations between cortical functional changes and clinical symptoms. In particular, delta and alpha NPV changes in the left-dorsal FC (F3) correlated with changes in gait status, while alpha and beta NPV changes in the right anterior prefrontal cortex (PFC) (Fp2) and left DLPFC (F7) as well as alpha NPV changes in the medial FC (Fz) correlated with changes in gait velocity. In addition, alpha NPV changes in the right DLPFC (F8) correlated with changes in WMS-R Mental Control scores in iNPH patients. An additional analysis combining the changes in values of alpha NPV over the left-dorsal FC (?alpha-F3-NPV) and the medial FC (?alpha-Fz-NPV) induced by CSF tapping (cut-off value of ?alpha-F3-NPV + ?alpha-Fz-NPV = 0), could correctly identified “shunt responders” and “shunt nonresponders” with a positive predictive value of 100% (10/10) and a negative predictive value of 66% (2/3). In contrast, EEG power spectral analysis showed no function related changes in cortical activity at the frontal cortex before and after CSF tapping. These results indicate that the clinical changes in gait and response suppression induced by CSF tapping in iNPH patients manifest as NPV changes, particularly in the alpha band, rather than as EEG power changes. Our findings suggest that NAT analysis can detect CSF tapping-induced functional changes in cortical activity, in a way that no other neuroimaging methods have been able to do so far, and can predict clinical response to shunt operation in patients with iNPH. PMID:24273735

Aoki, Yasunori; Kazui, Hiroaki; Tanaka, Toshihisa; Ishii, Ryouhei; Wada, Tamiki; Ikeda, Shunichiro; Hata, Masahiro; Canuet, Leonides; Musha, Toshimitsu; Matsuzaki, Haruyasu; Imajo, Kaoru; Yoshiyama, Kenji; Yoshida, Tetsuhiko; Shimizu, Yoshiro; Nomura, Keiko; Iwase, Masao; Takeda, Masatoshi

2013-01-01

223

Acute EEG findings in children with febrile status epilepticus  

PubMed Central

ABSTRACT Objective: The FEBSTAT (Consequences of Prolonged Febrile Seizures) study is prospectively addressing the relationships among serial EEG, MRI, and clinical follow-up in a cohort of children followed from the time of presentation with febrile status epilepticus (FSE). Methods: We recruited 199 children with FSE within 72 hours of presentation. Children underwent a detailed history, physical examination, MRI, and EEG within 72 hours. All EEGs were read by 2 teams and then conferenced. Associations with abnormal EEG were determined using logistic regression. Interrater reliability was assessed using the ? statistic. Results: Of the 199 EEGs, 90 (45.2%) were abnormal with the most common abnormality being focal slowing (n = 47) or attenuation (n = 25); these were maximal over the temporal areas in almost all cases. Epileptiform abnormalities were present in 13 EEGs (6.5%). In adjusted analysis, the odds of focal slowing were significantly increased by focal FSE (odds ratio [OR] = 5.08) and hippocampal T2 signal abnormality (OR = 3.50) and significantly decreased with high peak temperature (OR = 0.18). Focal EEG attenuation was also associated with hippocampal T2 signal abnormality (OR = 3.3). Conclusions: Focal EEG slowing or attenuation are present in EEGs obtained within 72 hours of FSE in a substantial proportion of children and are highly associated with MRI evidence of acute hippocampal injury. These findings may be a sensitive and readily obtainable marker of acute injury associated with FSE. PMID:23136262

Moshé, Solomon L.; Shinnar, Shlomo; Hesdorffer, Dale C.; Sogawa, Yoshimi; Pellock, John M.; Lewis, Darrell V.; Frank, L. Matthew; Shinnar, Ruth C.; Sun, Shumei

2012-01-01

224

Preliteracy signatures of poor-reading abilities in resting-state EEG  

PubMed Central

The hereditary character of dyslexia suggests the presence of putative underlying neural anomalies already in preliterate age. Here, we investigated whether early neurophysiological correlates of future reading difficulties—a hallmark of dyslexia—could be identified in the resting-state EEG of preliterate children. The children in this study were recruited at birth and classified on the basis of parents' performance on reading tests to be at-risk of becoming poor readers (n = 48) or not (n = 14). Eyes-open rest EEG was measured at the age of 3 years, and the at-risk children were divided into fluent readers (n = 24) and non-fluent readers (n = 24) after reading assessment at their third grade of school. We found that fluent readers and non-fluent readers differed in normalized spectral amplitude. Non-fluent readers were characterized by lower amplitude in the delta-1 frequency band (0.5–2 Hz) and higher amplitude in the alpha-1 band (6–8 Hz) in multiple scalp regions compared to control and at-risk fluent readers. Interestingly, across groups these EEG biomarkers correlated with several behavioral test scores measured in the third grade. Specifically, the performance on reading fluency, phonological and orthographic tasks and rapid automatized naming task correlated positively with delta-1 and negatively with alpha-1. Together, our results suggest that combining family-risk status, neurophysiological testing and behavioral test scores in a longitudinal setting may help uncover physiological mechanisms implicated with neurodevelopmental disorders such as the predisposition to reading disabilities. PMID:25285075

Schiavone, Giuseppina; Linkenkaer-Hansen, Klaus; Maurits, Natasha M.; Plakas, Anna; Maassen, Ben A. M.; Mansvelder, Huibert D.; van der Leij, Aryan; van Zuijen, Titia L.

2014-01-01

225

[A case of MM1+2 Creutzfeldt-Jakob disease with a longitudinal study of EEG and MRI].  

PubMed

We report a case of definite MM1 + 2 sporadic Creutzfeldt-Jakob disease (sCJD). A 66-year-old woman was admitted to our hospital with memory disturbance and disorientation for three months. On admission she presented a progressive cognitive insufficiency. Electroencephalography (EEG) revealed a frontal intermittent rhythmical delta activity (FIRDA) and the brain magnetic resonance imaging (MRI) showed high signal intensities in cerebral cortex on diffusion weighted images (DWI). After four months from the onset, she reached the akinetic mutism state followed by myoclonus. Follow up examination revealed that periodic synchronous discharge (PSD) was found in EEG, and DWI revealed enlargement of high signal intensity lesions in cerebral cortex. At seven months from the onset, PSD and high signal intensities of cortex became unclear with disappearance of myoclonus, and brain white matter lesions were evident on MRI. Serial studies of EEG and MRI revealed that PSD generalized from frontal lobe dominant pattern, while high signal intensity lesions of cortex diffusely increased on DWI. At ten months from the onset patient died. Pathological examination in brain showed moderate and diffuse neuronal cell loss and gliosis in cerebral cortex corresponding with DWI changes. The genotype at codon 129 of the prion protein (PrP) was homozygous methionine (MM) and the type of protease-resistant PrP (PrPres) was the mixed type of 1 and 2 in Western blot analysis. It has been rare to analyze the changes of EEG and MRI in the entire stage and to investigate pathological finding in the case of sCJD-MM1 + 2. A longitudinal examination of EEG and MRI is useful for early diagnosis of CJD. Also we could correlate these findings with clinical and histopathological phenotype. PMID:24450104

Katsube, Mizuho; Shiota, Yuri; Harada, Takayuki; Shibata, Hiroshi; Nagai, Atsushi

2013-11-01

226

Identification of spatial and temporal features of EEG Nisrine Jrad, Marco Congedo  

E-print Network

activities is a challenging task since Electroencephalography (EEG) recordings exhibit distinct understanding. Keywords: Brain computer interface (BCI), Electroencephalography (EEG), Global Field Power (GFP

Boyer, Edmond

227

NUMERICAL MATHEMATICS OF THE SUBTRACTION METHOD FOR THE MODELING OF A CURRENT DIPOLE IN EEG SOURCE  

E-print Network

. GRASEDYCK2 AND W. HACKBUSCH2 Abstract. In electroencephalography (EEG) source analysis, a dipole is widely source reconstruction. Electroencephalography (EEG) based source reconstruction of cerebral activity (the

Utah, University of

228

EEG microstate sequences in healthy humans at rest reveal scale-free dynamics  

E-print Network

electroencephalography (EEG) microstates as the electrophysiological correlates of fMRI resting-state networks about their underlying temporal dynamics. Multichannel electroencephalography (EEG) is a key method

229

Neuronal Correlates of Maladaptive Coping: An EEG-Study in Tinnitus Patients  

PubMed Central

Here we aimed to investigate the neuronal correlates of different coping styles in patients suffering from chronic tinnitus. Adaptive and maladaptive coping styles were determined in 85 tinnitus patients. Based on resting state EEG recordings, coping related differences in brain activity and connectivity were found. Maladaptive coping behavior was related to increases in subjective tinnitus loudness and distress, higher tinnitus severity and higher depression scores. EEG recordings demonstrated increased alpha activity over the left dorsolateral prefrontal cortex (DLPFC) and subgenual anterior cingulate cortex (sgACC) as well as increased connectivity in the default (i.e. resting state) network in tinnitus patients with a maladaptive coping style. Correlation analysis revealed that the changes in the DLPFC correlate primarily with maladaptive coping behavior, whereas the changes in the sgACC correlate with tinnitus severity and depression. Our findings are in line with previous research in the field of depression that during resting state a alpha band hyperconnectivity exists within the default network for patients who use a maladaptive coping style, with the sgACC as the dysfunctional node and that the strength of the connectivity is related to focusing on negative mood and catastrophizing about the consequences of tinnitus. PMID:24558383

Vanneste, Sven; Joos, Kathleen; Langguth, Berthold; To, Wing Ting; De Ridder, Dirk

2014-01-01

230

Using single-trial EEG to predict and analyze subsequent memory.  

PubMed

We show that it is possible to successfully predict subsequent memory performance based on single-trial EEG activity before and during item presentation in the study phase. Two-class classification was conducted to predict subsequently remembered vs. forgotten trials based on subjects' responses in the recognition phase. The overall accuracy across 18 subjects was 59.6% by combining pre- and during-stimulus information. The single-trial classification analysis provides a dimensionality reduction method to project the high-dimensional EEG data onto a discriminative space. These projections revealed novel findings in the pre- and during-stimulus periods related to levels of encoding. It was observed that the pre-stimulus information (specifically oscillatory activity between 25 and 35Hz) -300 to 0ms before stimulus presentation and during-stimulus alpha (7-12Hz) information between 1000 and 1400ms after stimulus onset distinguished between recollection and familiarity while the during-stimulus alpha information and temporal information between 400 and 800ms after stimulus onset mapped these two states to similar values. PMID:24064073

Noh, Eunho; Herzmann, Grit; Curran, Tim; de Sa, Virginia R

2014-01-01

231

Action observation and motor imagery in performance of complex movements: Evidence from EEG and kinematics analysis.  

PubMed

Motor imagery (MI) and action observation (AO) are considered effective cognitive tools for motor learning, but little work directly compared their cortical activation correlate in relation with subsequent performance. We compared AO and MI in promoting early learning of a complex four-limb, hand-foot coordination task, using electroencephalographic (EEG) and kinematic analysis. Thirty healthy subjects were randomly assigned into three groups to perform a training period in which AO watched a video of the task, MI had to imagine it, and Control (C) was involved in a distracting computation task. Subjects were then asked to actually perform the motor task with kinematic measurement of error time with respect to the correct motor performance. EEG was recorded during baseline, training and task execution, with task-related power (TRPow) calculation for sensorimotor (alpha and beta) rhythms reactive with respect to rest. During training, the AO group had a stronger alpha desynchronization than the MI and C over frontocentral and bilateral parietal areas. However, during task execution, AO group had greater beta synchronization over bilateral parietal regions than MI and C groups. This beta synchrony furthermore demonstrated the strongest association with kinematic errors, which was also significantly lower in AO than in MI. These data suggest that sensorimotor activation elicited by action observation enhanced motor learning according to motor performance, corresponding to a more efficient activation of cortical resources during task execution. Action observation may be more effective than motor imagery in promoting early learning of a new complex coordination task. PMID:25532912

Gonzalez-Rosa, Javier J; Natali, Fabrizio; Tettamanti, Andrea; Cursi, Marco; Velikova, Svetla; Comi, Giancarlo; Gatti, Roberto; Leocani, Letizia

2015-03-15

232

[Peculiarities of EEG dynamics in cognitive activity demanding persistent attention in patients with schizophrenia and schizoaffective psychosis and their relatives].  

PubMed

The search for neurophysiologic correlates of attention and working memory dysfunction in families with schizophrenia, 55 patients with schizophrenia and schizoaffective psychosis, 91 unaffected first degree relatives and 48 mentally normal subjects without family history of mental disorders have been studied. Changes in power of 5 EEG frequency bands in 16 records during serial mental arithmetic tasks were analyzed. Abnormalities in EEG reactivity were found both in patients and their relatives. Both groups were characterized by diffuse elevation of delta-rhythm power, the signs of hypoactivation and inversion of reaction asymmetry for different rhythm bands in the frontal area. In relatives, more pronounced attention dysfunction corresponded to more expressed abnormalities in EEG reactivity. Moreover, patients demonstrated insufficient depression of alpha and fast waves activity in the posterior cortex areas relevant to arithmetic activity. The results obtained allow considering an impaired reaction of alpha and fast rhythms inhibition in the posterior cortex areas as characteristic of the disease, and diffuse elevation of delta-waves power and frontal lobe hypoactivation with the inversion of reaction asymmetry as familial features that might reflect an impact of the factors predisposing to psychosis. This predisposition emerged during the cognitive task involving sustained attention and working memory. PMID:16180499

Uvarova, L G; Alfimova, M V

2005-01-01

233

EEG activity during movement planning encodes upcoming peak speed and acceleration and improves the accuracy in predicting hand kinematics.  

PubMed

The relationship between movement kinematics and human brain activity is an important and fundamental question for the development of neural prosthesis. The peak velocity and the peak acceleration could best reflect the feedforward-type movement; thus, it is worthwhile to investigate them further. Most related studies focused on the correlation between kinematics and brain activity during the movement execution or imagery. However, human movement is the result of the motor planning phase as well as the execution phase and researchers have demonstrated that statistical correlations exist between EEG activity during the motor planning and the peak velocity and the peak acceleration using grand-average analysis. In this paper, we examined whether the correlations were concealed in trial-to-trial decoding from the low signal-to-noise ratio of EEG activity. The alpha and beta powers from the movement planning phase were combined with the alpha and beta powers from the movement execution phase to predict the peak tangential speed and acceleration. The results showed that EEG activity from the motor planning phase could also predict the peak speed and the peak acceleration with a reasonable accuracy. Furthermore, the decoding accuracy of the peak speed and the peak acceleration could both be improved by combining band powers from the motor planning phase with the band powers from the movement execution. PMID:24893371

Yang, Lingling; Leung, Howard; Plank, Markus; Snider, Joe; Poizner, Howard

2015-01-01

234

Neural dynamics necessary and sufficient for transition into pre-sleep induced by EEG neurofeedback.  

PubMed

The transition from being fully awake to pre-sleep occurs daily just before falling asleep; thus its disturbance might be detrimental. Yet, the neuronal correlates of the transition remain unclear, mainly due to the difficulty in capturing its inherent dynamics. We used an EEG theta/alpha neurofeedback to rapidly induce the transition into pre-sleep and simultaneous fMRI to reveal state-dependent neural activity. The relaxed mental state was verified by the corresponding enhancement in the parasympathetic response. Neurofeedback sessions were categorized as successful or unsuccessful, based on the known EEG signature of theta power increases over alpha, temporally marked as a distinct "crossover" point. The fMRI activation was considered before and after this point. During successful transition into pre-sleep the period before the crossover was signified by alpha modulation that corresponded to decreased fMRI activity mainly in sensory gating related regions (e.g. medial thalamus). In parallel, although not sufficient for the transition, theta modulation corresponded with increased activity in limbic and autonomic control regions (e.g. hippocampus, cerebellum vermis, respectively). The post-crossover period was designated by alpha modulation further corresponding to reduced fMRI activity within the anterior salience network (e.g. anterior cingulate cortex, anterior insula), and in contrast theta modulation corresponded to the increased variance in the posterior salience network (e.g. posterior insula, posterior cingulate cortex). Our findings portray multi-level neural dynamics underlying the mental transition from awake to pre-sleep. To initiate the transition, decreased activity was required in external monitoring regions, and to sustain the transition, opposition between the anterior and posterior parts of the salience network was needed, reflecting shifting from extra- to intrapersonal based processing, respectively. PMID:24768931

Kinreich, Sivan; Podlipsky, Ilana; Jamshy, Shahar; Intrator, Nathan; Hendler, Talma

2014-08-15

235

Emergence of Synchronous EEG Spindles From Asynchronous MEG Spindles  

PubMed Central

Sleep spindles are bursts of rhythmic 10–15 Hz activity, lasting ~0.5–2 s, that occur during Stage 2 sleep. They are coherent across multiple cortical and thalamic locations in animals, and across scalp EEG sites in humans, suggesting simultaneous generation across the cortical mantle. However, reports of MEG spindles occurring without EEG spindles, and vice versa, are inconsistent with synchronous distributed generation. We objectively determined the frequency of MEG-only, EEG-only, and combined MEG-EEG spindles in high density recordings of natural sleep in humans. About 50% of MEG spindles occur without EEG spindles, but the converse is rare (~15%). Compared to spindles that occur in MEG only, those that occur in both MEG and EEG have ~1% more MEG coherence and ~15% more MEG power, insufficient to account for the ~55% increase in EEG power. However, these combined spindles involve ~66% more MEG channels, especially over frontocentral cortex. Furthermore, when both MEG and EEG are involved in a given spindle, the MEG spindle begins ~150 ms before the EEG spindle and ends ~250 ms after. Our findings suggest that spindles begin in focal cortical locations which are better recorded with MEG gradiometers than referential EEG due to the biophysics of their propagation. For some spindles, only these regions remain active. For other spindles, these locations may recruit other areas over the next 200 ms, until a critical mass is achieved, including especially frontal cortex, resulting in activation of a diffuse and/or multifocal generator that is best recorded by referential EEG derivations due to their larger leadfields. PMID:21337472

Dehghani, Nima; Cash, Sydney S.; Halgren, Eric

2013-01-01

236

Standardized Computer-based Organized Reporting of EEG: SCORE  

PubMed Central

The electroencephalography (EEG) signal has a high complexity, and the process of extracting clinically relevant features is achieved by visual analysis of the recordings. The interobserver agreement in EEG interpretation is only moderate. This is partly due to the method of reporting the findings 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). A working group of EEG experts took part in consensus workshops in Dianalund, Denmark, in 2010 and 2011. The faculty was approved by the Commission on European Affairs of the International League Against Epilepsy (ILAE). The working group produced a consensus proposal that went through a pan-European review process, organized by the European Chapter of the International Federation of Clinical Neurophysiology. The Standardised Computer-based Organised Reporting of EEG (SCORE) software was constructed based on the terms and features of the consensus statement and it was tested in the clinical practice. The main elements of SCORE are the following: personal data of the patient, referral data, recording conditions, modulators, background activity, drowsiness and sleep, interictal findings, “episodes” (clinical or subclinical events), physiologic patterns, patterns of uncertain significance, artifacts, polygraphic channels, and diagnostic significance. The following specific aspects of the neonatal EEGs are scored: alertness, temporal organization, and spatial organization. For each EEG finding, relevant features are scored using predefined terms. Definitions are provided for all EEG terms and features. 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. PMID:23506075

Beniczky, Sándor; Aurlien, Harald; Brøgger, Jan C; Fuglsang-Frederiksen, Anders; Martins-da-Silva, António; Trinka, Eugen; Visser, Gerhard; Rubboli, Guido; Hjalgrim, Helle; Stefan, Hermann; Rosén, Ingmar; Zarubova, Jana; Dobesberger, Judith; Alving, Jørgen; Andersen, Kjeld V; Fabricius, Martin; Atkins, Mary D; Neufeld, Miri; Plouin, Perrine; Marusic, Petr; Pressler, Ronit; Mameniskiene, Ruta; Hopfengärtner, Rüdiger; Emde Boas, Walter; Wolf, Peter

2013-01-01

237

Medial profrontal cortex and anterior cingulate cortex in the generation of alpha activity induced by transcendental meditation: a magnetoencephalographic study.  

PubMed

Previous EEG studies have shown that transcendental meditation (TM) increases frontal and central alpha activity. The present study was aimed at identifying the source of this alpha activity using magnetoencephalography (MEG) and electroencephalography (EEG) simultaneously on eight TM practitioners before, during, and after TM. The magnetic field potentials corresponding to TM-induced alpha activities on EEG recordings were extracted, and we attempted to localize the dipole sources using the multiple signal classification (MUSIC) algorithm, equivalent current dipole source analysis, and the multiple spatio-temporal dipole model. Since the dipoles were mapped to both the medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC), it is suggested that the mPFC and ACC play an important role in brain activity induced by TM. PMID:16508689

Yamamoto, Shin; Kitamura, Yoshihiro; Yamada, Norihito; Nakashima, Yoshihiko; Kuroda, Shigetoshi

2006-02-01

238

Pattern changes of EEG oscillations and BOLD signals associated with temporal lobe epilepsy as revealed by a working memory task  

PubMed Central

Background It is known that the abnormal neural activity in epilepsy may be associated to the reorganization of neural circuits and brain plasticity in various ways. On that basis, we hypothesized that changes in neuronal circuitry due to epilepsy could lead to measurable variations in patterns of both EEG and BOLD signals in patients performing some cognitive task as compared to what would be obtained in normal condition. Thus, the aim of this study was to compare the cerebral areas involved in EEG oscillations versus fMRI signal patterns during a working memory (WM) task in normal controls and patients with refractory mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS). The study included six patients with left MTLE-HS (left-HS group) and seven normal controls (control group) matched to the patients by age and educational level, both groups undergoing a blocked design paradigm based on Sternberg test during separated EEG and fMRI sessions. This test consisted of encoding and maintenance of a variable number of consonant letters on WM. Results EEG analysis for the encoding period revealed the presence of theta and alpha oscillations in the frontal and parietal areas, respectively. Likewise, fMRI showed the co-occurrence of positive and negative BOLD signals in both brain regions. As for the maintenance period, whereas EEG analysis revealed disappearance of theta oscillation, fMRI showed decrease of positive BOLD in frontal area and increase of negative BOLD in the posterior part of the brain. Conclusions Generally speaking, these patterns of electrophysiological and hemodynamic signals were observed for both control and left-HS groups. However, the data also revealed remarkable differences between these groups that are consistent with the hypothesis of reorganization of brain circuitry associated with epilepsy. PMID:24766708

2014-01-01

239

On the analysis of EEG power, frequency and asymmetry in Parkinson’s disease during emotion processing  

PubMed Central

Objective While Parkinson’s disease (PD) has traditionally been described as a movement disorder, there is growing evidence of disruption in emotion information processing associated with the disease. The aim of this study was to investigate whether there are specific electroencephalographic (EEG) characteristics that discriminate PD patients and normal controls during emotion information processing. Method EEG recordings from 14 scalp sites were collected from 20 PD patients and 30 age-matched normal controls. Multimodal (audio-visual) stimuli were presented to evoke specific targeted emotional states such as happiness, sadness, fear, anger, surprise and disgust. Absolute and relative power, frequency and asymmetry measures derived from spectrally analyzed EEGs were subjected to repeated ANOVA measures for group comparisons as well as to discriminate function analysis to examine their utility as classification indices. In addition, subjective ratings were obtained for the used emotional stimuli. Results Behaviorally, PD patients showed no impairments in emotion recognition as measured by subjective ratings. Compared with normal controls, PD patients evidenced smaller overall relative delta, theta, alpha and beta power, and at bilateral anterior regions smaller absolute theta, alpha, and beta power and higher mean total spectrum frequency across different emotional states. Inter-hemispheric theta, alpha, and beta power asymmetry index differences were noted, with controls exhibiting greater right than left hemisphere activation. Whereas intra-hemispheric alpha power asymmetry reduction was exhibited in patients bilaterally at all regions. Discriminant analysis correctly classified 95.0% of the patients and controls during emotional stimuli. Conclusion These distributed spectral powers in different frequency bands might provide meaningful information about emotional processing in PD patients. PMID:24716619

2014-01-01

240

Using EEG to Study Cognitive Development: Issues and Practices  

ERIC Educational Resources Information Center

Developmental research is enhanced by use of multiple methodologies for examining psychological processes. The electroencephalogram (EEG) is an efficient and relatively inexpensive method for the study of developmental changes in brain-behavior relations. In this review, we highlight some of the challenges for using EEG in cognitive development…

Bell, Martha Ann; Cuevas, Kimberly

2012-01-01

241

EEG-based Emotion Recognition Using Discriminative Graph Regularized  

E-print Network

EEG-based Emotion Recognition Using Discriminative Graph Regularized Extreme Learning Machine Jia and negative emotions of subjects. We introduce a new effective classifier named discriminative graph (EEG) [6], electromyogram (EMG) [7], electrocardiogram (ECG) [8], skin resistance (SR) [9] and pulse

Lu, Bao-Liang

242

Effects of Fipronil on the EEG of Long Evans Rats  

EPA Science Inventory

We have reported that the non-stimulus driven EEG is differentially altered by deltamethrin or permethrin (Lyke and Herr, Toxicologist, 114(S-1):265, 2010). In the current study, we examined the ability to detect changes in EEG activity produced by fipronil, a phenylpyrazole pest...

243

Intuitionistic fuzzy approach in enhancing image of flat EEG  

NASA Astrophysics Data System (ADS)

Image enhancement is a process to improve the quality of an image which mainly due to presence of noise. It is an initial step in medical imaging. Fuzzy approach has been used widely in the area of image processing. However, in this paper, image enhancement of Flat EEG (fEEG) during epileptic seizures using intuitionistic fuzzy set (IFS) is presented and compared.

Zenian, Suzelawati; Ahmad, Tahir; Idris, Amidora

2014-07-01

244

Monte Carlo Simulation Studies of EEG and MEG Localization Accuracy  

E-print Network

Monte Carlo Simulation Studies of EEG and MEG Localization Accuracy Arthur K. Liu, Anders M. Dale activity. The accuracy of source localization depends on numerous factors, including the specific inverse approach and source model, fundamental differences in EEG and MEG data, and the accuracy of the volume

Sereno, Martin

245

A Mixture of Experts Network Structure for EEG Signals Classification  

Microsoft Academic Search

This paper illustrates the use of mixture of experts (ME) network structure to guide model selection for classification of electroencephalogram (EEG) signals. Expectation-maximization (EM) algorithm was used for training the ME so that the learning process is decoupled in a manner that fits well with the modular structure. The EEG signals were decomposed into time-frequency representations using discrete wavelet transform

I. Guler; E. Derya Ubeyli; N. Fatma Guler

2005-01-01

246

EEG Neurofeedback Treatment of Patients with Down Syndrome  

Microsoft Academic Search

Introduction: Down syndrome is the most common identifiable cause of intellectual disability, accounting for almost one third of cases and approximately 1 in 800 births. Neurofeedback (NF) is an operant conditioning method for retraining brain wave (EEG) patterns. An increasing number of clinicians use operant conditioning of EEG activity as a method of helping children with Attention Deficit Hyperactivity and

Tanju Sürmeli; Ayben Ertem

2007-01-01

247

Emotion recognition from EEG using higher order crossings  

Microsoft Academic Search

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

Panagiotis C. Petrantonakis; Leontios J. Hadjileontiadis

2010-01-01

248

EEG Markers for Attention Deficit Disorder: Pharmacological and Neurofeedback Applications.  

ERIC Educational Resources Information Center

Examined contribution of EEG findings in the classification and treatment of attention deficit and related behavioral problems in children. Found that quantitative EEG methods disclosed patterns of abnormality in children with ADD, suggested improved guidelines for pharmacological treatment, and introduced neurofeedback, a behavioral treatment for…

Sterman, M. Barry

2000-01-01

249

Juvenile myoclonic epilepsy: A clinical and sleep EEG study  

Microsoft Academic Search

Juvenile myoclonic epilepsy (JME) is characterized by myoclonic jerks on awakening, generalized tonic–clonic seizures (GTCS) and is associated with absence seizures in more than one third of cases. Fifteen patients with juvenile myoclonic epilepsy were studied with regard to their clinical profile, EEG data and sleep EEG findings. There was a delay in the diagnosis of JME (mean of 3.5

A. K. Dhanuka; B. K. Jain; Singh Daljit; D. Maheshwari

2001-01-01

250

Classification of EEG abnormalities in partial epilepsy with simultaneous EEG-fMRI recordings.  

PubMed

Scalp EEG recordings and the classification of interictal epileptiform discharges (IED) in patients with epilepsy provide valuable information about the epileptogenic network, particularly by defining the boundaries of the "irritative zone" (IZ), and hence are helpful during pre-surgical evaluation of patients with severe refractory epilepsies. The current detection and classification of epileptiform signals essentially rely on expert observers. This is a very time-consuming procedure, which also leads to inter-observer variability. Here, we propose a novel approach to automatically classify epileptic activity and show how this method provides critical and reliable information related to the IZ localization beyond the one provided by previous approaches. We applied Wave_clus, an automatic spike sorting algorithm, for the classification of IED visually identified from pre-surgical simultaneous Electroencephalogram-functional Magnetic Resonance Imagining (EEG-fMRI) recordings in 8 patients affected by refractory partial epilepsy candidate for surgery. For each patient, two fMRI analyses were performed: one based on the visual classification and one based on the algorithmic sorting. This novel approach successfully identified a total of 29 IED classes (compared to 26 for visual identification). The general concordance between methods was good, providing a full match of EEG patterns in 2 cases, additional EEG information in 2 other cases and, in general, covering EEG patterns of the same areas as expert classification in 7 of the 8 cases. Most notably, evaluation of the method with EEG-fMRI data analysis showed hemodynamic maps related to the majority of IED classes representing improved performance than the visual IED classification-based analysis (72% versus 50%). Furthermore, the IED-related BOLD changes revealed by using the algorithm were localized within the presumed IZ for a larger number of IED classes (9) in a greater number of patients than the expert classification (7 and 5, respectively). In contrast, in only one case presented the new algorithm resulted in fewer classes and activation areas. We propose that the use of automated spike sorting algorithms to classify IED provides an efficient tool for mapping IED-related fMRI changes and increases the EEG-fMRI clinical value for the pre-surgical assessment of patients with severe epilepsy. PMID:24830841

Pedreira, C; Vaudano, A E; Thornton, R C; Chaudhary, U J; Vulliemoz, S; Laufs, H; Rodionov, R; Carmichael, D W; Lhatoo, S D; Guye, M; Quian Quiroga, R; Lemieux, L

2014-10-01

251

Multimodal emotion recognition using EEG and eye tracking data.  

PubMed

This paper presents a new emotion recognition method which combines electroencephalograph (EEG) signals and pupillary response collected from eye tracker. We select 15 emotional film clips of 3 categories (positive, neutral and negative). The EEG signals and eye tracking data of five participants are recorded, simultaneously, while watching these videos. We extract emotion-relevant features from EEG signals and eye tracing data of 12 experiments and build a fusion model to improve the performance of emotion recognition. The best average accuracies based on EEG signals and eye tracking data are 71.77% and 58.90%, respectively. We also achieve average accuracies of 73.59% and 72.98% for feature level fusion strategy and decision level fusion strategy, respectively. These results show that both feature level fusion and decision level fusion combining EEG signals and eye tracking data can improve the performance of emotion recognition model. PMID:25571125

Wei-Long Zheng; Bo-Nan Dong; Bao-Liang Lu

2014-08-01

252

Amplitude Integrated EEG: The Child Neurologist’s Perspective  

PubMed Central

Neurologists increasingly recognize that critically ill patients are at high risk for seizures - particularly non-convulsive seizures - and that neuromonitoring is a useful tool for diagnosing seizures and assessing brain function in these patients. Amplitude-integrated electroencephalography (aEEG) is a simplified bedside neurophysiology tool that has become widely used in neonates over the past decade. Despite widespread interest by both neurologists and neonatologists in continuous brain monitoring, aEEG has been largely ignored by neurologists, forcing neonatologists to “go it alone” when interpreting data from this bedside tool. Although aEEG cannot replace conventional EEG for background monitoring and detection of seizures, it remains a useful instrument that complements conventional EEG, is being widely adopted by neonatologists, and should be supported by neonatal neurologists. PMID:23690296

Glass, Hannah C.; Wusthoff, Courtney J.; Shellhaas, Renée A.

2014-01-01

253

Asthma Phenotypes: Nonallergic (Intrinsic) Asthma.  

PubMed

The definition of nonallergic asthma includes that subset of subjects with asthma and with whom allergic sensitization cannot be demonstrated. These individuals should have negative skin prick test or in vitro specific-IgE test to a panel of seasonal and perennial allergens. Nonallergic asthma occurs in 10% to 33% of individuals with asthma and has a later onset than allergic asthma, with a female predominance. Nonallergic asthma appears to be more severe than allergic asthma in many cases and may be less responsive to standard therapy. Although many of the immunopathologic features of nonallergic asthma are similar to those observed with allergic asthma, some differences have been described, including a higher expression of RANTES in mucosa and bronchoalveolar lavage fluid, as well as a higher GM-CSF receptor alpha expression. Unbiased statistical methods, such as cluster analysis and latent class analysis, indicate that the lack of atopy is not the most important defining factor in assigning an individual to many specific phenotypes but rather is more important in some phenotypes than others, and appears to modulate the clinical expression of the disease. Despite an appreciation of this clinical entity for many years, many of its clinical implications remain unclear. PMID:25439352

Peters, Stephen P

254

Computer-aided diagnosis of alcoholism-related EEG signals.  

PubMed

Alcoholism is a severe disorder that affects the functionality of neurons in the central nervous system (CNS) and alters the behavior of the affected person. Electroencephalogram (EEG) signals can be used as a diagnostic tool in the evaluation of subjects with alcoholism. The neurophysiological interpretation of EEG signals in persons with alcoholism (PWA) is based on observation and interpretation of the frequency and power in their EEGs compared to EEG signals from persons without alcoholism. This paper presents a review of the known features of EEGs obtained from PWA and proposes that the impact of alcoholism on the brain can be determined by computer-aided analysis of EEGs through extracting the minute variations in the EEG signals that can differentiate the EEGs of PWA from those of nonaffected persons. The authors advance the idea of automated computer-aided diagnosis (CAD) of alcoholism by employing the EEG signals. This is achieved through judicious combination of signal processing techniques such as wavelet, nonlinear dynamics, and chaos theory and pattern recognition and classification techniques. A CAD system is cost-effective and efficient and can be used as a decision support system by physicians in the diagnosis and treatment of alcoholism especially those who do not specialize in alcoholism or neurophysiology. It can also be of great value to rehabilitation centers to assess PWA over time and to monitor the impact of treatment aimed at minimizing or reversing the effects of the disease on the brain. A CAD system can be used to determine the extent of alcoholism-related changes in EEG signals (low, medium, high) and the effectiveness of therapeutic plans. PMID:25461226

Acharya, U Rajendra; S, Vidya; Bhat, Shreya; Adeli, Hojjat; Adeli, Amir

2014-12-01

255

Evidence of a Faster Posterior Dominant EEG Rhythm in Children with Autism  

ERIC Educational Resources Information Center

Multiple electroencephalography (EEG) abnormalities have been associated with autism. In the course of clinical work, we have observed a posterior dominant EEG rhythm at higher frequency in children with autism. To test this observation, 56 EEG tracings of children with autism were compared to the EEGs of age-matched controls. Children with autism…

Gregory, Michael D.; Mandelbaum, David E.

2012-01-01

256

Genetic disposition to alcoholism. An EEG study in alcoholics and their relatives  

Microsoft Academic Search

Family, twin, and adoption studies have shown that genetic factors are involved in the etiology of alcoholism. Based on earlier EEG findings in alcoholics and on the known genetic determination of the alcohol effect on the EEG, the hypothesis was tested whether the resting EEG reflects a certain disposition to alcoholism. Resting EEGs were examined for 115 alcoholics (78 males,

Peter Propping; Jens Krüger; Norbert Mark

1981-01-01

257

Estimating Single-Trial Responses in EEG  

NASA Technical Reports Server (NTRS)

Accurate characterization of single-trial field potential responses is critical from a number of perspectives. For example, it allows differentiation of an evoked response from ongoing EEG. We previously developed the multiple component Event Related Potential (mcERP) algorithm to improve resolution of the single-trial evoked response. The mcERP model states that multiple components, each specified by a stereotypic waveform varying in latency and amplitude from trial to trial, comprise the evoked response. Application of the mcERP algorithm to simulated data with three independent, synthetic components has shown that the model is capable of separating these components and estimating their variability. Application of the model to single trial, visual evoked potentials recorded simultaneously from all V1 laminae in an awake, fixating macaque yielded local and far-field components. Certain local components estimated by the model were distributed in both granular and supragranular laminae. This suggests a linear coupling between the responses of thalamo-recipient neuronal ensembles and subsequent responses of supragranular neuronal ensembles, as predicted by the feedforward anatomy of V1. Our results indicate that the mcERP algorithm provides a valid estimation of single-trial responses. This will enable analyses that depend on trial-to-trial variations and those that require separation of the evoked response from background EEG rhythms

Shah, A. S.; Knuth, K. H.; Truccolo, W. A.; Mehta, A. D.; Fu, K. G.; Johnston, T. A.; Ding, M.; Bressler, S. L.; Schroeder, C. E.; Clancy, Daniel (Technical Monitor)

2002-01-01

258

Nonlinear analysis of EEG for epileptic seizures  

SciTech Connect

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.

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

259

Dynamic EEG Changes during Cigarette Smoking  

Microsoft Academic Search

Electroencephalograms were monitored before, during and after smoking a single cigarette. Quantitative analysis indicated that smoking produced a characteristic psychostimulant profile involving power reductions in delta and theta and increases in both alpha power and peak alpha frequency. Puff-by-puff analysis yielded similar patterns with the effects emerging by the fourth puff. Delta reductions were evident during the act of puffing

Verner J. Knott

1988-01-01

260

Correlation between computed tomography and voltage and current source density spectral EEG parameters in patients with brain lesions.  

PubMed

In a group of patients with space-occupying brain lesions, CT measurements were correlated with absolute power (AP) and relative power (RP) of the delta, theta, alpha and beta EEG bands, calculated from the raw EEG potentials (EEGp) and from the Laplacian estimates also called "current source densities" (CSD). Rank correlations were calculated between the number of abnormal values in each band and the following CT measures: volume of the lesion and of the edema, density of the edema, percentage of ventricular collapse and midline shift. Abnormal spectral values are those which are significantly higher than the norm for the same age, in the delta and theta bands, and significantly lower in the alpha and beta bands. Spectral parameters obtained from the CSD showed higher correlations with CT measures than those calculated from the EEGp. In the Laplacian, all CT measures had a significant correlation with delta AP. Theta AP was significantly correlated with the volume and density of the edema, as well as with midline shift. Significant correlations were also observed with delta and alpha RP. However, changes in RP were considered to be a consequence of the increase in delta AP. Canonical correlation analyses between AP and RP calculated from EEGp or CSD and the first 3 CT measures showed that the volume of the lesion was only correlated with delta AP and RP. The volume and density of the edema showed a significant correlation with delta, theta and alpha AP calculated from EEGp and only with theta and alpha AP in the Laplacian. Since the EEGp tends to produce a more extensive and diffuse picture of abnormality, whereas the Laplacian acts as a spatial filter emphasizing local sources over distant sources, we concluded that edema is related not to delta activity, but to the theta and alpha power. PMID:7691550

Harmony, T; Fernández-Bouzas, A; Marosi, E; Fernández, T; Bernal, J; Rodríguez, M; Reyes, A; Silva, J; Alonso, M; Casian, G

1993-10-01

261

Topographical frequency dynamics within EEG and MEG sleep spindles  

PubMed Central

Objective Spindles are rhythmic bursts of 10–16Hz activity, lasting ~1s, occur during normal stage 2 sleep. Spindles are slower in frontal EEG and possibly MEG. The posterior-fast EEG pattern may predominate early in the spindle, and the anterior-slow pattern late. We aimed to determine the proportion of spindles showing this spatio-spectro-temporal interaction for EEG, and whether it occurs in MEG. Methods We recorded high density EEG and MEG from 7 healthy subjects during normal stage 2 sleep. High vs. low frequency (12 vs. 14 Hz) power was measured early vs. late (25th–45th vs. 55th–75th duration percentile) in 183 spindle discharges. Results The predicted spatio-spectro-temporal interaction was shown by 48% of EEG and 34% of MEG spindles (chance=25%). Topographically, high frequency EEG power was greatest at midline central contacts, and low frequency power at midline frontal. This frequency-specific topography was fixed over the course of the spindle. Conclusions An evolution from posterior-fast to anterior-slow generators commonly occurs during spindles, and this is visible with EEG and to a lesser extent, MEG. Significance The spatio-spectral-temporal evolution of spindles may reflect their possible involvement in coordinating cortical activity during consolidation. PMID:20637689

Dehghani, Nima; Cash, Sydney S.; Halgren, Eric

2010-01-01

262

Higher-Order Spectrum in Understanding Nonlinearity in EEG Rhythms  

PubMed Central

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. PMID:22400046

Pradhan, Cauchy; Jena, Susant K.; Nadar, Sreenivasan R.; Pradhan, N.

2012-01-01

263

Mobile Collection and Automated Interpretation of EEG Data  

NASA Technical Reports Server (NTRS)

A system that would comprise mobile and stationary electronic hardware and software subsystems has been proposed for collection and automated interpretation of electroencephalographic (EEG) data from subjects in everyday activities in a variety of environments. By enabling collection of EEG data from mobile subjects engaged in ordinary activities (in contradistinction to collection from immobilized subjects in clinical settings), the system would expand the range of options and capabilities for performing diagnoses. Each subject would be equipped with one of the mobile subsystems, which would include a helmet that would hold floating electrodes (see figure) in those positions on the patient s head that are required in classical EEG data-collection techniques. A bundle of wires would couple the EEG signals from the electrodes to a multi-channel transmitter also located in the helmet. Electronic circuitry in the helmet transmitter would digitize the EEG signals and transmit the resulting data via a multidirectional RF patch antenna to a remote location. At the remote location, the subject s EEG data would be processed and stored in a database that would be auto-administered by a newly designed relational database management system (RDBMS). In this RDBMS, in nearly real time, the newly stored data would be subjected to automated interpretation that would involve comparison with other EEG data and concomitant peer-reviewed diagnoses stored in international brain data bases administered by other similar RDBMSs.

Mintz, Frederick; Moynihan, Philip

2007-01-01

264

Optimal spatial filtering of single trial EEG during imagined hand movement  

Microsoft Academic Search

The development of an EEG-based brain-computer interface (BCI) requires rapid and reliable discrimination of EEG patterns, e. g., associated with motor imagery. One sided hand movement imagination results in EEG changes located at contra- and ipsilateral central areas. We demonstrate that spatial filters for multi-channel EEG effectively extract discriminatory information from two populations of single-trial EEG, recorded during left and

H. Ramoser; J. Müller-gerking; G. Pfurtscheller

1998-01-01

265

Correlation of EEG activities between slow-wave sleep and wakefulness in patients with supra-tentorial stroke.  

PubMed

Using topographic EEG mapping, we studied the relationships between delta activity during slow-wave sleep (SWS) and the background EEG activity during wakefulness, in 11 normal subjects and 35 stroke patients with unilateral supra-tentorial lesions. Delta-1 power during SWS showed a significant positive correlation with alpha-1 power during wakefulness, in both hemispheres. Delta-1 and delta-2 power during SWS correlated positively not only with alpha-2 power, but also with delta-1 and delta-2 power during wakefulness in the affected hemisphere. these figures indicate that the amount of delta activity during SWS can be associated with that of alpha activity during wakefulness. A close negative correlation was observed between delta power during SWS and the age of the subjects in the patient group. The Barthel index showed no significant correlation with delta-1 or delta-2 power in either hemisphere in patient group. Our results suggest that delta activity during SWS may be associated with dysfunction of the cerebral cortex in stroke patients as well as in normal aged subjects. PMID:8728417

Yokoyama, E; Nagata, K; Hirata, Y; Satoh, Y; Watahiki, Y; Yuya, H

1996-01-01

266

Wireless brain-machine interface using EEG and EOG: brain wave classification and robot control  

NASA Astrophysics Data System (ADS)

A brain-machine interface (BMI) links a user's brain activity directly to an external device. It enables a person to control devices using only thought. Hence, it has gained significant interest in the design of assistive devices and systems for people with disabilities. In addition, BMI has also been proposed to replace humans with robots in the performance of dangerous tasks like explosives handling/diffusing, hazardous materials handling, fire fighting etc. There are mainly two types of BMI based on the measurement method of brain activity; invasive and non-invasive. Invasive BMI can provide pristine signals but it is expensive and surgery may lead to undesirable side effects. Recent advances in non-invasive BMI have opened the possibility of generating robust control signals from noisy brain activity signals like EEG and EOG. A practical implementation of a non-invasive BMI such as robot control requires: acquisition of brain signals with a robust wearable unit, noise filtering and signal processing, identification and extraction of relevant brain wave features and finally, an algorithm to determine control signals based on the wave features. In this work, we developed a wireless brain-machine interface with a small platform and established a BMI that can be used to control the movement of a robot by using the extracted features of the EEG and EOG signals. The system records and classifies EEG as alpha, beta, delta, and theta waves. The classified brain waves are then used to define the level of attention. The acceleration and deceleration or stopping of the robot is controlled based on the attention level of the wearer. In addition, the left and right movements of eye ball control the direction of the robot.

Oh, Sechang; Kumar, Prashanth S.; Kwon, Hyeokjun; Varadan, Vijay K.

2012-04-01

267

Fractal Dimension of EEG Activity Senses Neuronal Impairment in Acute Stroke  

PubMed Central

The brain is a self-organizing system which displays self-similarities at different spatial and temporal scales. Thus, the complexity of its dynamics, associated to efficient processing and functional advantages, is expected to be captured by a measure of its scale-free (fractal) properties. Under the hypothesis that the fractal dimension (FD) of the electroencephalographic signal (EEG) is optimally sensitive to the neuronal dysfunction secondary to a brain lesion, we tested the FD’s ability in assessing two key processes in acute stroke: the clinical impairment and the recovery prognosis. Resting EEG was collected in 36 patients 4–10 days after a unilateral ischemic stroke in the middle cerebral artery territory and 19 healthy controls. National Health Institute Stroke Scale (NIHss) was collected at T0 and 6 months later. Highuchi FD, its inter-hemispheric asymmetry (FDasy) and spectral band powers were calculated for EEG signals. FD was smaller in patients than in controls (1.447±0.092 vs 1.525±0.105) and its reduction was paired to a worse acute clinical status. FD decrease was associated to alpha increase and beta decrease of oscillatory activity power. Larger FDasy in acute phase was paired to a worse clinical recovery at six months. FD in our patients captured the loss of complexity reflecting the global system dysfunction resulting from the structural damage. This decrease seems to reveal the intimate nature of structure-function unity, where the regional neural multi-scale self-similar activity is impaired by the anatomical lesion. This picture is coherent with neuronal activity complexity decrease paired to a reduced repertoire of functional abilities. FDasy result highlights the functional relevance of the balance between homologous brain structures’ activities in stroke recovery. PMID:24967904

Zappasodi, Filippo; Olejarczyk, Elzbieta; Marzetti, Laura; Assenza, Giovanni; Pizzella, Vittorio; Tecchio, Franca

2014-01-01

268

Alpha-1 Antitrypsin Deficiency  

MedlinePLUS

... Liver > Liver Disease Information > Alpha-1 Antitrypsin Deficiency Alpha-1 Antitrypsin Deficiency Explore this section to learn more about alpha-1 antitrypsin deficiency, including a description of the ...

269

[Changes of EEG power spectrum in response to the emotional auditory stimuli in patients in acute and recovery stages of TBI (traumatic brain injury)].  

PubMed

We investigated variability of responses to emotionally important auditory stimulation in different groups of TBI (Traumatic Brain Injury) in acute state or recovery. The patients sampling consisted of three different groups: patients in coma or vegetative state, patients with Severe and Moderate TBI in recovery period. Subjects were stimulated with auditory stimuli containing important physiological sounds (coughing, vomiting), emotional sounds (laughing, crying), nature sounds (bird song, barking), unpleasant household sounds (nails scratching the glass), natural sounds (sea, rain, fire) and neutral sounds (white noise). The background encephalographic activity was registered during at least 7 minutes. EEG was recorded while using portable device "Entsefalan". Significant differences of power of the rhythmic activity registered during the presentation of different types of stimuli were analyzed using Mathlab and Statistica 6.0. Results showed that EEG-response to the emotional stimuli differed depending on consciousness level, stimuli type, severity of TBI. Most valuable changes in EEG spectrum power for a patient with TBI were found for unpleasant auditory stimulation. Responsiveness to the pleasant stimulation could be registered in later stages of coming out of coma than to unpleasant stimulation. Alpha-activity is reducing in patients with TBI: the alpha rhythm depression is most evident in the control group, less in group after moderate TBI, and even less in group after severe TBI. Patients in coma or vegetative state didn't show any response in rhythmic power in the frequency of alpha rhythm. PMID:25508396

2013-01-01

270

[Changes of EEG power spectrum in response to the emotional auditory stimuli in patients in acute and recovery stages of TBI (traumatic brain injury)].  

PubMed

We investigated variability of responses to emotionally important auditory stimulation in different groups of TBI (Traumatic Brain Injury) in acute state or recovery. The patients sampling consisted of three different groups: patients in coma or vegetative state, patients with Severe and Moderate TBI in recovery period. Subjects were stimulated with auditory stimuli containing important physiological sounds (coughing, vomiting), emotional sounds (laughing, crying), nature sounds (bird song, barking), unpleasant household sounds (nails scratching the glass), natural sounds (sea, rain, fire) and neutral sounds (white noise). The background encephalographic activity was registered during at least 7 minutes. EEG was recorded while using portable device "Entsefalan". Significant differences of power of the rhythmic activity registered during the presentation of different types of stimuli were analyzed using Mathlab and Statistica 6.0. Results showed that EEG-response to the emotional stimuli differed depending on consciousness level, stimuli type, severity of TBI. Most valuable changes in EEG spectrum power for a patient with TBI were found for unpleasant auditory stimulation. Responsiveness to the pleasant stimulation could be registered in later stages of coming out of coma than to unpleasant stimulation. Alpha-activity is reducing in patients with TBI: the alpha rhythm depression is most evident in the control group, less in group after moderate TBI, and even less in group after severe TBI. Patients in coma or vegetative state didn't show any response in rhythmic power in the frequency of alpha rhythm. PMID:25464765

Portnova, G V; Gladun, K V; Sharova, E A; Ivanitski?, A M

2013-01-01

271

Never Resting Brain: Simultaneous Representation of Two Alpha Related Processes in Humans  

PubMed Central

Brain activity is continuously modulated, even at “rest”. The alpha rhythm (8–12 Hz) has been known as the hallmark of the brain's idle-state. However, it is still debated if the alpha rhythm reflects synchronization in a distributed network or focal generator and whether it occurs spontaneously or is driven by a stimulus. This EEG/fMRI study aimed to explore the source of alpha modulations and their distribution in the resting brain. By serendipity, while computing the individually defined power modulations of the alpha-band, two simultaneously occurring components of these modulations were found. An ‘induced alpha’ that was correlated with the paradigm (eyes open/ eyes closed), and a ‘spontaneous alpha’ that was on-going and unrelated to the paradigm. These alpha components when used as regressors for BOLD activation revealed two segregated activation maps: the ‘induced map’ included left lateral temporal cortical regions and the hippocampus; the ‘spontaneous map’ included prefrontal cortical regions and the thalamus. Our combined fMRI/EEG approach allowed to computationally untangle two parallel patterns of alpha modulations and underpin their anatomical basis in the human brain. These findings suggest that the human alpha rhythm represents at least two simultaneously occurring processes which characterize the ‘resting brain’; one is related to expected change in sensory information, while the other is endogenous and independent of stimulus change. PMID:19096714

Arieli, Amos; Zhdanov, Andrey; Hendler, Talma

2008-01-01

272

Recent EEG and ERP Findings in Substance Abusers  

PubMed Central

Research on electroencephalographic (EEG) correlates of substance use has a long history. The present paper provides a review of recent studies – 2001 to the present – with a focus on EEG findings in human participants characterized by a history of chronic substance use, abuse or dependence. In some areas (e.g., alcohol and cocaine dependence), the field has attempted to build upon earlier work by incorporating different methodologies or pursuing research questions of a transdisciplinary nature. New areas of inquiry, such as the investigation of EEG differences among users of ecstasy (MDMA) and methamphetamine, have emerged, primarily as a result of an alarming rise in popularity of these drugs. PMID:19534304

Ceballos, Natalie A.; Bauer, Lance O.; Houston, Rebecca J.

2009-01-01

273

Rational manipulation of digital EEG: pearls and pitfalls.  

PubMed

The advent of digital EEG has provided greater flexibility and more opportunities in data analysis to optimize the diagnostic yield. Changing the filter settings, sensitivity, montages, and time-base are possible rational manipulations to achieve this goal. The options to use polygraphy, video, and quantification are additional useful features. Aliasing and loss of data are potential pitfalls in the use of digital EEG. This review illustrates some common clinical scenarios where rational manipulations can enhance the diagnostic EEG yield and potential pitfalls in the process. PMID:25462135

Seneviratne, Udaya

2014-12-01

274

Melancholia EEG classification based on CSSD and SVM  

NASA Astrophysics Data System (ADS)

It takes an important role to get the disease information from melancholia electroencephalograph (EEG). Firstly, A common spatial subspace decomposition (CSSD) method was used to extract features from 16-channel EEG of melancholia and normal healthy persons. Then based on support vector machines (SVM), a classifier was designed to train and test its classification capability between Melancholia and healthy persons. The results indicated that the proposed method can reach a higher accuracy as 95% in EEG classification, while the accuracy of the method based on wavelet is only 88%.That is, the proposed method is feasible for the melancholia diagnosis and research.

Shi, Jian-Jun; Yuan, Qing-Wu; Zhou, La-Wu

2011-10-01

275

No effects of a single 3G UMTS mobile phone exposure on spontaneous EEG activity, ERP correlates, and automatic deviance detection.  

PubMed

Potential effects of a 30?min exposure to third generation (3G) Universal Mobile Telecommunications System (UMTS) mobile phone-like electromagnetic fields (EMFs) were investigated on human brain electrical activity in two experiments. In the first experiment, spontaneous electroencephalography (sEEG) was analyzed (n?=?17); in the second experiment, auditory event-related potentials (ERPs) and automatic deviance detection processes reflected by mismatch negativity (MMN) were investigated in a passive oddball paradigm (n?=?26). Both sEEG and ERP experiments followed a double-blind protocol where subjects were exposed to either genuine or sham irradiation in two separate sessions. In both experiments, electroencephalograms (EEG) were recorded at midline electrode sites before and after exposure while subjects were watching a silent documentary. Spectral power of sEEG data was analyzed in the delta, theta, alpha, and beta frequency bands. In the ERP experiment, subjects were presented with a random series of standard (90%) and frequency-deviant (10%) tones in a passive binaural oddball paradigm. The amplitude and latency of the P50, N100, P200, MMN, and P3a components were analyzed. We found no measurable effects of a 30?min 3G mobile phone irradiation on the EEG spectral power in any frequency band studied. Also, we found no significant effects of EMF irradiation on the amplitude and latency of any of the ERP components. In summary, the present results do not support the notion that a 30?min unilateral 3G EMF exposure interferes with human sEEG activity, auditory evoked potentials or automatic deviance detection indexed by MMN. PMID:22674213

Trunk, Attila; Stefanics, Gábor; Zentai, Norbert; Kovács-Bálint, Zsófia; Thuróczy, György; Hernádi, István

2013-01-01

276

Gelastic seizures: Incidence, clinical and EEG features in adult patients undergoing video-EEG telemetry.  

PubMed

This study aimed to determine clinical features of adult patients with gelastic seizures recorded on video -electroencephalography (EEG) over a 5-year period. We screened video-EEG telemetry reports for the occurrence of the term "gelastic" seizures, and assessed the semiology, EEG features, and duration of those seizures. Gelastic seizures were identified in 19 (0.8%) of 2,446 admissions. The presumed epileptogenic zone was in the hypothalamus in one third of the cases, temporal lobe epilepsy was diagnosed in another third, and the remainder of the cases presenting with gelastic seizures were classified as frontal, parietal lobe epilepsy or remained undetermined or were multifocal. Gelastic seizures were embedded in a semiology, with part of the seizure showing features of automotor seizures. A small proportion of patients underwent epilepsy surgery. Outcome of epilepsy surgery was related to the underlying pathology; two patients with hippocampal sclerosis had good outcomes following temporal lobe resection and one of four patients with hypothalamic hamartomas undergoing gamma knife surgery had a good outcome. PMID:25516460

Kovac, Stjepana; Diehl, Beate; Wehner, Tim; Fois, Chiara; Toms, Nathan; Walker, Matthew C; Duncan, John S

2015-01-01

277

Assessment of cortical response during motor task in adults by a multimodality approach based on fNIRS-EEG, fMRI-EEG, and TMS  

NASA Astrophysics Data System (ADS)

A multimodality approach based on fNIRS-EEG, fMRI-EEG and TMS was used on adult volunteers during motor task aiming at optimizing a functional imaging procedure to be eventually used on patients with movement disorders.

Torricelli, Alessandro; Contini, Davide; Caffini, Matteo; Zucchelli, Lucia; Cubeddu, Rinaldo; Spinelli, Lorenzo; Molteni, Erika; Bianchi, Anna Maria; Baselli, Giuseppe; Cerutti, Sergio; Visani, Elisa; Gilioli, Isabella; Rossi Sebastiano, Davide; Schiaffi, Elena; Panzica, Ferruccio; Franceschetti, Silvana

2011-07-01

278

A coarse-grained analysis of the functional brain connectivity from EEG recordings of a visuo-perceptual discrimination task  

NASA Astrophysics Data System (ADS)

We report the emergent functional connectivity of cortical areas during a visuo-perceptual discrimination task with or without the retention in memory of the location of visual targets using EEG. The networks were computed using multivariate Granger causality on groups of electrodes reflecting coarse-grained brain areas. The analysis showed that at alpha band (8-12Hz) there are no significant differences. In contrast, in beta and gamma band, we identified a top-down information flow pattern which was evident for the task that required the activation of the working memory mechanism.

Protopapa, Foteini; Mylonas, Dimitris; Smyrnis, Nikolaos; Siettos, Constantinos

2013-10-01

279

Biomechanics Phenotypic plasticity in  

E-print Network

Biomechanics Phenotypic plasticity in juvenile jellyfish medusae facilitates effective animal and altered functionality. Previous studies have indicated that Scyphozoan jellyfish ontogeny accommo- dates; ontogeny; jellyfish 1. INTRODUCTION The swimming and feeding performance of marine ani- mals depends

Dabiri, John O.

280

Phenotypic Variation in Plants  

NSDL National Science Digital Library

This resource is a detailed manual of protocols and instructional information for carrying out an undergraduate laboratory exercise in ecology and evolutionary biolog. Students examine the causes of phenotypic variation in Brassica rapa. This exercise provides an excellent example of potential factors associated with the causes of phenotypic variation for lower division undergraduates, but could also be expanded upon to allow unique scientific inquiry in labs for upper-division undergrads. It includes student outlines, instructor's notes, and suggested questions for laboratory reports.

Lawrence Blumer (Morehouse College;)

1997-01-01

281

Disabling conditional inferences: an EEG study.  

PubMed

Although the Modus Ponens inference is one of the most basic logical rules, decades of conditional reasoning research show that it is often rejected when people consider stored background knowledge about potential disabling conditions. In the present study we used EEG to identify neural markers of this process. We presented participants with many and few disabler conditionals for which retrieval of disabling conditions was likely or unlikely. As in classic behavioral studies we observed that participants accepted the standard MP conclusion less for conditionals with many disablers. The key finding was that the presentation of the standard MP conclusion also resulted in a more pronounced N2 and less pronounced P3b for the many disabler conditionals. This specific N2/P3b pattern has been linked to the violation and satisfaction of expectations, respectively. Thereby, the present ERP findings support the idea that disabler retrieval lowers reasoners' expectations that the standard MP conclusion can be drawn. PMID:24508764

Bonnefond, Mathilde; Kaliuzhna, Mariia; Van der Henst, Jean-Baptiste; De Neys, Wim

2014-04-01

282

Simple and difficult mathematics in children: a minimum spanning tree EEG network analysis.  

PubMed

Sensor-level network characteristics associated with arithmetic tasks varying in complexity were estimated using tools from modern network theory. EEG signals from children with math difficulties (MD) and typically achieving controls (NI) were analyzed using minimum spanning tree (MST) indices derived from Phase Lag Index values - a graph method that corrects for comparison bias. Results demonstrated progressive modulation of certain MST parameters with increased task difficulty. These findings were consistent with more distributed network activation in the theta band, and greater network integration (i.e., tighter communication between involved regions) in the alpha band as task demands increased. There was also evidence of stronger intraregional signal inter-dependencies in the higher frequency bands during the complex math task. Although these findings did not differ between groups, several MST parameters were positively correlated with individual performance on psychometric math tasks involving similar operations, especially in the NI group. The findings support the potential utility of MST analyses to evaluate function-related electrocortical reactivity over a wide range of EEG frequencies in children. PMID:24887585

Vourkas, Michael; Karakonstantaki, Eleni; Simos, Panagiotis G; Tsirka, Vasso; Antonakakis, Marios; Vamvoukas, Michael; Stam, Cornelis; Dimitriadis, Stavros; Micheloyannis, Sifis

2014-07-25

283

Internal and external spatial attention examined with lateralized EEG power spectra.  

PubMed

Several authors argued that retrieval of an item from visual short term memory (internal spatial attention) and focusing attention on an externally presented item (external spatial attention) are similar. Part of the neuroimaging support for this view may be due to the employed experimental procedures. Furthermore, as internal spatial attention may have a more induced than evoked nature some effects may not have been visible in event related analyses of the electroencephalogram (EEG), which limits the possibility to demonstrate differences. In the current study, a colored frame cued which stimulus, one out of four presented in separate quadrants, required a response, which depended on the form of the cued stimulus (circle or square). Importantly, the frame occurred either before (precue), simultaneously with (simultaneous cue), or after the stimuli (postcue). The precue and simultaneous cue condition both concern external attention, while the postcue condition implies the involvement of internal spatial attention. Event-related lateralizations (ERLs), reflecting evoked effects, and lateralized power spectra (LPS), reflecting both evoked and induced effects, were determined. ERLs revealed a posterior contralateral negativity (PCN) only in the precue condition. LPS analyses on the raw EEG showed early increased contralateral theta power at posterior sites and later increased ipsilateral alpha power at occipito-temporal sites in all cue conditions. Responses were faster when the internally or externally attended location corresponded with the required response side than when not. These findings provide further support for the view that internal and external spatial attention share their underlying mechanism. PMID:25130665

Van der Lubbe, Rob H J; Bundt, Carsten; Abrahamse, Elger L

2014-10-01

284

EEG precursors of detected and missed targets during free-viewing search.  

PubMed

When scanning a scene, the target of our search may be in plain sight and yet remain unperceived. Conversely, at other times the target may be perceived in the periphery prior to fixation. There is ample behavioral and neurophysiological evidence to suggest that in some constrained visual-search tasks, targets are detected prior to fixational eye movements. However, limited human data are available during unconstrained search to determine the time course of detection, the brain areas involved, and the neural correlates of failures to detect a foveated target. Here, we recorded and analyzed electroencephalographic (EEG) activity during free-viewing visual search, varying the task difficulty to compare neural signatures for detected and unreported ("missed") targets. When carefully controlled to remove eye-movement-related potentials, saccade-locked EEG shows that: (a) "Easy" targets may be detected as early as 150 ms prior to foveation, as indicated by a premotor potential associated with a button response; (b) object-discriminating occipital activity emerges during the saccade to target; and (c) success and failures to detect a target are accompanied by a modulation in alpha-band power over fronto-central areas as well as altered saccade dynamics. Taken together, these data suggest that target detection during free viewing can begin prior to and continue during a saccade, with failure or success in reporting a target possibly resulting from inhibition or activation of fronto-central processing areas associated with saccade control. PMID:24222183

Dias, João C; Sajda, Paul; Dmochowski, Jacek P; Parra, Lucas C

2013-01-01

285

Temporal dynamics of EEG activity during short- and long-wavelength light exposures in the early morning  

PubMed Central

Background It is well known that exposure to light, especially of short wavelength, enhances human alertness during the nighttime. However, more information is needed to elucidate the effects of light wavelength on alertness at other times of day. The present study investigated how two narrowband light spectra affected human alertness during the morning after awakening. We measured electroencephalography (EEG) during 48-minute exposure to narrowband short- and long-wavelength light and darkness in the early morning. Results Power densities of EEG during each light exposure were calculated. The time course of EEG power indicated that, compared with remaining in darkness, the power in the alpha frequency range (8–13 Hz) was significantly lower after approximately 30 minutes of exposures to both the short- and the long-wavelength light. Conclusions These results suggest that not only short-wavelength light but also long-wavelength light, which does not suppress melatonin levels at night, can affect alertness in the early morning. These results suggest that the alerting effects of light in the early morning hours may be mediated by mechanisms other than those that are exclusively sensitive to short-wavelength light. PMID:24568149

2014-01-01

286

EEG classification in a single-trial basis for vowel speech perception using multivariate empirical mode decomposition  

NASA Astrophysics Data System (ADS)

Objective. The objective of this study is to find components that might be related to phoneme representation in the brain and to discriminate EEG responses for each speech sound on a trial basis. Approach. We used multivariate empirical mode decomposition (MEMD) and common spatial pattern for feature extraction. We chose three vowel stimuli, /a/, /i/ and /u/, based on previous findings, such that the brain can detect change in formant frequency (F2) of vowels. EEG activity was recorded from seven native Korean speakers at Gwangju Institute of Science and Technology. We applied MEMD over EEG channels to extract speech-related brain signal sources, and looked for the intrinsic mode functions which were dominant in the alpha bands. After the MEMD procedure, we applied the common spatial pattern algorithm for enhancing the classification performance, and used linear discriminant analysis (LDA) as a classifier. Main results. The brain responses to the three vowels could be classified as one of the learned phonemes on a single-trial basis with our approach. Significance. The results of our study show that brain responses to vowels can be classified for single trials using MEMD and LDA. This approach may not only become a useful tool for the brain-computer interface but it could also be used for discriminating the neural correlates of categorical speech perception.

Kim, Jongin; Lee, Suh-Kyung; Lee, Boreom

2014-06-01

287

Generation and Reproductive Phenotypes of Mice Lacking Estrogen Receptor beta  

Microsoft Academic Search

Estrogens influence the differentiation and maintenance of reproductive tissues and affect lipid metabolism and bone remodeling. Two estrogen receptors (ERs) have been identified to date, ERalpha and ERbeta . We previously generated and studied knockout mice lacking estrogen receptor alpha and reported severe reproductive and behavioral phenotypes including complete infertility of both male and female mice and absence of breast

John H. Krege; Jeffrey B. Hodgin; John F. Couse; Eva Enmark; Margaret Warner; Joel F. Mahler; Madhabananda Sar; Kenneth S. Korach; Jan-Ake Gustafsson; Oliver Smithies

1998-01-01

288

Multimodal Spatial Calibration for Accurately Registering EEG Sensor Positions  

PubMed Central

This paper proposes a fast and accurate calibration method to calibrate multiple multimodal sensors using a novel photogrammetry system for fast localization of EEG sensors. The EEG sensors are placed on human head and multimodal sensors are installed around the head to simultaneously obtain all EEG sensor positions. A multiple views' calibration process is implemented to obtain the transformations of multiple views. We first develop an efficient local repair algorithm to improve the depth map, and then a special calibration body is designed. Based on them, accurate and robust calibration results can be achieved. We evaluate the proposed method by corners of a chessboard calibration plate. Experimental results demonstrate that the proposed method can achieve good performance, which can be further applied to EEG source localization applications on human brain. PMID:24803954

Chen, Shengyong; Xiao, Gang; Li, Xiaoli

2014-01-01

289

Performance prediction using EEG and trial-invariant characteristic signals.  

PubMed

One of the most important parts of all applications trying to discriminate between a person's different mental tasks using their recorded EEG data is the process of feature construction. A common practice for this is to exploit an apriori knowledge about the nature of the mental processes of interest and their impact on the EEG signals. However, the use of features constructed in this way is restricted to applications concerning the corresponding mental processes. We present here a novel method for EEG data classification which is very general as it makes no assumptions about the nature of the EEG signals. It is based on the construction of a characteristic signal for each class which remains as invariant as possible over the trials belonging to that class. We use the proposed method in combination with a novel method for channel selection in an oddball experiment to predict a person's quick or late response. PMID:19163241

Varnavas, Andreas; Petrou, Maria

2008-01-01

290

Fractal Dimension in Eeg Signals during Muscle Fatigue  

NASA Astrophysics Data System (ADS)

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.

Huang, Haibin; Yao, Bin; Yue, Guang; Brown, Robert; Jing, Liu

2003-10-01

291

EEG (ELECTROENCEPHALOGRAM) AS A CROSS SPECIES INDICATOR OF NEUROTOXICITY  

EPA Science Inventory

The electroencephalogram (EEG) is a promising measure in the field of neurotoxicology. It can be well quantified by techniques which can be interpreted both physically and statistically. Such quantification schemes are briefly discussed in this paper. However, the quantification ...

292

Functional EEG mapping and SPECT in detoxified male alcoholics.  

PubMed

Fifteen alcoholics diagnosed according to DSM-III-R, who were detoxified for at least 2 weeks and showed no clinical withdrawal signs, were investigated with 16 channel EEG mapping during resting, manumotor and music perception conditions, and were compared with 13 control persons. Single photon emission computed tomography (SPECT) using hexa-methyl-propilene-amine-oxime (HMPAO) labeled with 99m-technetium (99mTc) as tracer was performed separately (in patients only) and submitted to semiquantitative region of interest (ROI) analysis in 2 slices, 6 and 10 cm above canthomeatal line, respectively. Resting EEG showed increased power values in fast beta frequency band for the detoxified alcoholics. On cortical stimulation, patients showed signs of pathological EEG reactivity. Correlations of EEG parameters to cerebral blood flow (CBF) values (patients only) yielded coefficients around zero for all frequency bands (signs of uncoupling). All findings point to organic brain dysfunctions in these patients which extend beyond the period of withdrawal. PMID:9224905

Günther, W; Müller, N; Knesewitsch, P; Haag, C; Trapp, W; Banquet, J P; Stieg, C; Alper, K R

1997-01-01

293

EEG-BASED SPEECH RECOGNITION Impact of Temporal Effects  

E-print Network

: Electroencephalography; Speech Recognition; Unspoken Speech. Abstract: In this paper, we investigate the use INTRODUCTION 1.1 Motivation Electroencephalography (EEG) has proven to be use- ful for a multitude of new

Schultz, Tanja

294

Coercively Adjusted Auto Regression Model for Forecasting in Epilepsy EEG  

PubMed Central

Recently, data with complex characteristics such as epilepsy electroencephalography (EEG) time series has emerged. Epilepsy EEG data has special characteristics including nonlinearity, nonnormality, and nonperiodicity. Therefore, it is important to find a suitable forecasting method that covers these special characteristics. In this paper, we propose a coercively adjusted autoregression (CA-AR) method that forecasts future values from a multivariable epilepsy EEG time series. We use the technique of random coefficients, which forcefully adjusts the coefficients with ?1 and 1. The fractal dimension is used to determine the order of the CA-AR model. We applied the CA-AR method reflecting special characteristics of data to forecast the future value of epilepsy EEG data. Experimental results show that when compared to previous methods, the proposed method can forecast faster and accurately. PMID:23710252

Kim, Sun-Hee; Faloutsos, Christos; Yang, Hyung-Jeong

2013-01-01

295

Detection of artifacts from high energy bursts in neonatal EEG.  

PubMed

Detection of non-cerebral activities or artifacts, intermixed within the background EEG, is essential to discard them from subsequent pattern analysis. The problem is much harder in neonatal EEG, where the background EEG contains spikes, waves, and rapid fluctuations in amplitude and frequency. Existing artifact detection methods are mostly limited to detect only a subset of artifacts such as ocular, muscle or power line artifacts. Few methods integrate different modules, each for detection of one specific category of artifact. Furthermore, most of the reference approaches are implemented and tested on adult EEG recordings. Direct application of those methods on neonatal EEG causes performance deterioration, due to greater pattern variation and inherent complexity. A method for detection of a wide range of artifact categories in neonatal EEG is thus required. At the same time, the method should be specific enough to preserve the background EEG information. The current study describes a feature based classification approach to detect both repetitive (generated from ECG, EMG, pulse, respiration, etc.) and transient (generated from eye blinking, eye movement, patient movement, etc.) artifacts. It focuses on artifact detection within high energy burst patterns, instead of detecting artifacts within the complete background EEG with wide pattern variation. The objective is to find true burst patterns, which can later be used to identify the Burst-Suppression (BS) pattern, which is commonly observed during newborn seizure. Such selective artifact detection is proven to be more sensitive to artifacts and specific to bursts, compared to the existing artifact detection approaches applied on the complete background EEG. Several time domain, frequency domain, statistical features, and features generated by wavelet decomposition are analyzed to model the proposed bi-classification between burst and artifact segments. A feature selection method is also applied to select the feature subset producing highest classification accuracy. The suggested feature based classification method is executed using our recorded neonatal EEG dataset, consisting of burst and artifact segments. We obtain 78% sensitivity and 72% specificity as the accuracy measures. The accuracy obtained using the proposed method is found to be about 20% higher than that of the reference approaches. Joint use of the proposed method with our previous work on burst detection outperforms reference methods on simultaneous burst and artifact detection. As the proposed method supports detection of a wide range of artifact patterns, it can be improved to incorporate the detection of artifacts within other seizure patterns and background EEG information as well. PMID:24209926

Bhattacharyya, Sourya; Biswas, Arunava; Mukherjee, Jayanta; Majumdar, Arun Kumar; Majumdar, Bandana; Mukherjee, Suchandra; Singh, Arun Kumar

2013-11-01

296

Dynamic links between theta executive functions and alpha storage buffers in auditory and visual working memory  

PubMed Central

Working memory (WM) tasks require not only distinct functions such as a storage buffer and central executive functions, but also coordination among these functions. Neuroimaging studies have revealed the contributions of different brain regions to different functional roles in WM tasks; however, little is known about the neural mechanism governing their coordination. Electroencephalographic (EEG) rhythms, especially theta and alpha, are known to appear over distributed brain regions during WM tasks, but the rhythms associated with task-relevant regional coupling have not been obtained thus far. In this study, we conducted time–frequency analyses for EEG data in WM tasks that include manipulation periods and memory storage buffer periods. We used both auditory WM tasks and visual WM tasks. The results successfully demonstrated function-specific EEG activities. The frontal theta amplitudes increased during the manipulation periods of both tasks. The alpha amplitudes increased during not only the manipulation but also the maintenance periods in the temporal area for the auditory WM and the parietal area for the visual WM. The phase synchronization analyses indicated that, under the relevant task conditions, the temporal and parietal regions show enhanced phase synchronization in the theta bands with the frontal region, whereas phase synchronization between theta and alpha is significantly enhanced only within the individual areas. Our results suggest that WM task-relevant brain regions are coordinated by distant theta synchronization for central executive functions, by local alpha synchronization for the memory storage buffer, and by theta–alpha coupling for inter-functional integration. PMID:20525081

Kawasaki, Masahiro; Kitajo, Keiichi; Yamaguchi, Yoko

2010-01-01

297

An analysis of EEG when acupuncture with wavelet entropy.  

PubMed

Wavelet energy entropy derived from wavelet multi-revolution decomposition, reconstruction and Shannon entropy can signify the complexity of unsteady EEG signals in both time domain and frequency domain. Firstly, the paper gives an introduction of the methods about wavelet energy entropy. Then the EEG signals when acupuncture is analyzed and some conclusions are addressed by using wavelet energy entropy, relative wavelet energy entropy and the time evolution of them. PMID:19162857

Li, Nuo; Wang, Jiang; Deng, Bin; Dong, Feng

2008-01-01

298

Design of Cranial Electrotherapy Stimulator and Analyzing It with EEG  

Microsoft Academic Search

\\u000a To design a portable low cost Cranial Electrotherapy Stimulator (CES) and to study the corresponding brain activity electrically.\\u000a The designed stimulator was used as an external trigger and the impact was analyzed using 20 lead EEG electrode system with\\u000a standard recording protocol. Subjects were tested under this and their corresponding normal and varying EEG with CES were\\u000a noted. Result showed

Gopalakrishnan Narayanamurthy; Mahesh Veezhinathan

299

Recording the sleep EEG with periorbital skin electrodes  

Microsoft Academic Search

The aim of the study was to examine whether the typical changes of the EEG in the course of a sleep episode can be recorded by skin electrodes placed at the outer canthi of the eyes. In sleep recording from young, healthy subjects, the signals from the electro-oculogram (EOG, El-A2) derivation and a central scalp EEG derivation (C3-A2) were compared.

Esther Werth; Alexander A. Borbely

1995-01-01

300

Measurement and modification of the EEG and related behavior  

NASA Technical Reports Server (NTRS)

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 will be able to detect appropriate changes in brain function, and feed this information to on-board computers for modification of mission requirements and/or crew status.

Sterman, M. B.

1991-01-01

301

Avoiding the pitfalls of EEG interpretation in childhood epilepsy.  

PubMed

The accurate interpretation of the electroencephalogram (EEG) of infants and children being evaluated for suspected epilepsy is based on the appreciation of normal and expected age-dependent characteristics, an awareness of the significance of both epileptiform and non-epileptiform activity, and the correlation of epileptiform abnormalities with clinical findings. Avoiding the pitfalls of pediatric EEG interpretation include the recognition of such normal EEG features in wakefulness as posterior slow waves of youth, mu rhythm, and lambda waves. In addition, the understanding of age-dependent characteristics of EEG state-changes is essential, such as: monorhythmic and paroxysmal hypnagogic hypersynchrony, special features of vertex transients and sleep spindles, positive occipital sharp transients, initial arousal responses and post-arousal hypersynchrony. The EEG response to activation procedures such as hyperventilation and photic stimulation may also be a source of confusion. Patterns of uncertain diagnostic significance also may be present in children, including 14- and 6-Hz bursts and rhythmic temporal theta bursts of drowsiness (the so-called psychomotor variant). Some nonepileptiform EEG abnormalities may also be misinterpreted as epileptiform. The determination of the clinical significance of spike foci and generalized abortive spike-and-wave may pose more of a problem as a potential pitfall than the identification by visual analysis of these interictal discharges. Another problem posed to the electroencephalographer is the determination of the EEG response to antiepileptic drug therapy including effect on spike foci, generalized spike-and-wave and electrical seizure activity, and effect on background activity. The recognition of the differences between the EEG of children and adults will provide the basis for more accurate interpretation and assist the electroencephalographer in avoiding the identification of normal, age-dependent features as epileptiform. PMID:8647051

Mizrahi, E M

1996-01-01

302

Positive sharp waves in the EEG of children and adults.  

PubMed

Interictal epileptiform discharges (IEDs) with negative polarity have been extensively studied in the EEG literature. However, little attention has been drawn to IED with positive polarity [positive sharp waves (PSWs)]. In this paper, we discuss pathophysiological, neuroimaging, and clinical correlates of this pattern in a heterogeneous group of children and adults who demonstrated PSW in their scalp EEG. We prospectively reviewed the EEGs of 1,250 patients from a heterogeneous population over a period of 1 year. Thirty-one patients had PSW in their EEG. We documented EEG parameters as well as demographic, clinical, and neuroimaging data. Statistical analysis was performed to correlate the aforementioned data. The analysis showed that PSW is an epileptogenic pattern with localizing significance, occurring primarily in the younger age groups. Furthermore, there was a strong association of PSW with chronic and/or static CNS pathology, in particular, congenital CNS anomalies, often accompanied by psychomotor retardation. Patients with "multifocal'' PSW invariably exhibited severe intellectual and motor deficits associated consistently with a variety of congenital CNS insults. PSW is a rare and under-reported EEG abnormality which, similar to negative IED, signifies focal epileptogenecity. The presence of PSW should prompt neuroimaging studies to investigate an associated chronic/static CNS pathology, in particular, congenital CNS anomalies. This association is particularly strong when PSW is multifocal in which case patients present with severe intellectual and motor deficits. PMID:24281945

Janati, A Bruce; Umair, Muhammad; Alghasab, Naif Saad; Al-Shurtan, Kareemah Salem

2014-05-01

303

Period-peak analysis of the EEG with microprocessor applications.  

PubMed

This paper describes the development and evaluation of a period-peak algorithm for background analysis of the clinical electroencephalogram (EEG). The procedure is a time-domain method which is harmonious with manual interpretation of the EEG tracing. Conceptually the algorithm functions in 2 modes. Major counts are detected by successive baseline crossings in the period analysis mode. Presence of superimposed activity between major-counts induces a transition to the peak-detection mode. In this manner, period-peak analysis is capable of detecting the simultaneity of slow base-waves and relatively fast superimposed activity in the EEG. Preliminary studies have been conducted in which the analysis results of this procedure were compared to those of other EEG algorithms. In general, the period-peak algorithm offered less bias towards either end of the EEG spectrum. Subsequent to testing of a FORTRAN version, the period-peak algorithm has been implemented in assembly language on a dedicated microprocessor system for on-line analysis of EEG data. PMID:7083831

Palem, K; Barr, R E

1982-04-01

304

Autoregressive model in the Lp norm space for EEG analysis.  

PubMed

The autoregressive (AR) model is widely used in electroencephalogram (EEG) analyses such as waveform fitting, spectrum estimation, and system identification. In real applications, EEGs are inevitably contaminated with unexpected outlier artifacts, and this must be overcome. However, most of the current AR models are based on the L2 norm structure, which exaggerates the outlier effect due to the square property of the L2 norm. In this paper, a novel AR object function is constructed in the Lp (p?1) norm space with the aim to compress the outlier effects on EEG analysis, and a fast iteration procedure is developed to solve this new AR model. The quantitative evaluation using simulated EEGs with outliers proves that the proposed Lp (p?1) AR can estimate the AR parameters more robustly than the Yule-Walker, Burg and LS methods, under various simulated outlier conditions. The actual application to the resting EEG recording with ocular artifacts also demonstrates that Lp (p?1) AR can effectively address the outliers and recover a resting EEG power spectrum that is more consistent with its physiological basis. PMID:25448380

Li, Peiyang; Wang, Xurui; Li, Fali; Zhang, Rui; Ma, Teng; Peng, Yueheng; Lei, Xu; Tian, Yin; Guo, Daqing; Liu, Tiejun; Yao, Dezhong; Xu, Peng

2015-01-30

305

Power spectrum analysis of EEG at diagnosis and follow up of patients with solvent induced chronic toxic encephalopathy.  

PubMed Central

Electroencephalographic changes have been studied in a group of 32 men aged 30-65 (mean 49) with diagnosed chronic toxic encephalopathy. The group had been carefully scrutinised for other possible causes of brain dysfunction and the diagnosis was based on neuraesthenic symptoms and pathological psychometric performance. The EEGs were recorded from four areas of the brain and the power spectrum analysed. Comparisons have been made with a group of 50 healthy male workers with no occupational exposure to solvents. For 24 of the 32 patients a follow up EEG recording was made after 17-75 months (mean 33). The results showed a doubling of the EEG power in the patients for all four recording channels with a significant reduction at follow up but not to the level of the control group. No exposure effect relation could be established. Acute exposure at the time of the first recording, exposure free, or follow up time did not influence the results. The frequency of the dominant EEG activity and the relative frequency distribution were equal in the two groups and did not change during the follow up period. Five of the 32 subjects took benzodiazepine drugs regularly and they had greater total power in all four recording channels compared with the other 27 patients; the difference was not statistically significant. The relative frequency distribution showed less alpha- and more theta- and beta-power in these five subjects. A reduction in total power during follow up was also found in the subgroup that took benzodiazepines.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3395583

Orbaek, P; Rosén, I; Svensson, K

1988-01-01

306

EEG Source Reconstruction Reveals Frontal-Parietal Dynamics of Spatial Conflict Processing  

PubMed Central

Cognitive control requires the suppression of distracting information in order to focus on task-relevant information. We applied EEG source reconstruction via time-frequency linear constrained minimum variance beamforming to help elucidate the neural mechanisms involved in spatial conflict processing. Human subjects performed a Simon task, in which conflict was induced by incongruence between spatial location and response hand. We found an early (?200 ms post-stimulus) conflict modulation in stimulus-contralateral parietal gamma (30–50 Hz), followed by a later alpha-band (8–12 Hz) conflict modulation, suggesting an early detection of spatial conflict and inhibition of spatial location processing. Inter-regional connectivity analyses assessed via cross-frequency coupling of theta (4–8 Hz), alpha, and gamma power revealed conflict-induced shifts in cortical network interactions: Congruent trials (relative to incongruent trials) had stronger coupling between frontal theta and stimulus-contrahemifield parietal alpha/gamma power, whereas incongruent trials had increased theta coupling between medial frontal and lateral frontal regions. These findings shed new light into the large-scale network dynamics of spatial conflict processing, and how those networks are shaped by oscillatory interactions. PMID:23451201

Cohen, Michael X; Ridderinkhof, K. Richard

2013-01-01

307

A novel self-guided approach to alpha activity training.  

PubMed

Fifty healthy participants took part in a double-blind placebo-controlled study in which they were either given auditory alpha activity (8-12Hz) training (N=18), random beta training (N=12), or no training at all (N=20). A novel wireless electrode system was used for training without instructions, involving water-based electrodes mounted in an audio headset. Training was applied approximately at central electrodes. Post-training measurement using a conventional full-cap EEG system revealed a 10% increase in alpha activity at posterior sites compared to pre-training levels, when using the conventional index of alpha activity and a non-linear regression fit intended to model individual alpha frequency. This statistically significant increase was present only in the group that received the alpha training, and remained evident at a 3 month follow-up session, especially under eyes open conditions where an additional 10% increase was found. In an exit interview, approximately twice as many participants in the alpha training group (53%) mentioned that the training was relaxing, compared to those in either the beta (20%) or no training (21%) control groups. Behavioural measures of stress and relaxation were indicative of effects of alpha activity training but failed to reach statistical significance. These results are discussed in terms of a lack of statistical power. Overall, results suggest that self-guided alpha activity training using this novel system is feasible and represents a step forward in the ease of instrumental conditioning of brain rhythms. PMID:22119661

van Boxtel, Geert J M; Denissen, Ad J M; Jäger, Mark; Vernon, David; Dekker, Marian K J; Mihajlovi?, Vojkan; Sitskoorn, Margriet M

2012-03-01

308

Early effect of NEURAPAS® balance on current source density (CSD) of human EEG  

PubMed Central

Psychiatric patients often suffer from stress, anxiety and depression. Various plant extracts are known to fight stress (valerian), anxiety (passion flower) or depression (St. John's wort). NEURAPAS® balance is a mixture of these three extracts and has been designed to cover this complex of psychiatric conditions. The study was initiated to quantitatively assess the effect of this combination on brain electric activity. Method Quantitative electroencephalogram (EEG) current source density (CSD) recording from 16 healthy male and female human volunteers (average age 49 years) was used in a randomized, placebo-controlled cross over study. Recordings were performed 0. 5, 1. 5, 3 and 4 hours after administration of the preparations under the conditions of 6 min eyes open and 5 min d2 concentration test, mathematical calculation test and memory test, respectively. All variables (electric power within 6 frequency ranges at 17 electrode positions) were fed into a linear discriminant analysis (eyes open condition). In the presence of mental load these variables were used to construct brain maps of frequency changes. Results Under the condition of mental load, centro-parietal spectral power remained statistically significantly lower within alpha1, alpha2 and beta1 frequencies in the presence of verum in comparison to placebo. Discriminant analysis revealed a difference to placebo 3 and 4 hours after intake of 6 tablets of NEURAPAS® balance. Data location within the polydimensional space was projected into the area of the effects of sedative and anti-depressive reference drugs tested earlier under identical conditions. Results appeared closer to the effects of fluoxetine than to St. John's wort. Conclusions Analysis of the neurophysiological changes following the intake of NEURAPAS® balance revealed a similarity of frequency changes to those of calming and anti-depressive drugs on the EEG without impairment of cognition. Trial registration ClinicalTrials.gov: NCT01047605 PMID:21810233

2011-01-01

309

Simultaneous recording of MEG, EEG and intracerebral EEG during visual stimulation: from feasibility to single-trial analysis.  

PubMed

Electroencephalography (EEG), magnetoencephalography (MEG), and intracerebral stereotaxic EEG (SEEG) are the three neurophysiological recording techniques, which are thought to capture the same type of brain activity. Still, the relationships between non-invasive (EEG, MEG) and invasive (SEEG) signals remain to be further investigated. In early attempts at comparing SEEG with either EEG or MEG, the recordings were performed separately for each modality. However such an approach presents substantial limitations in terms of signal analysis. The goal of this technical note is to investigate the feasibility of simultaneously recording these three signal modalities (EEG, MEG and SEEG), and to provide strategies for analyzing this new kind of data. Intracerebral electrodes were implanted in a patient with intractable epilepsy for presurgical evaluation purposes. This patient was presented with a visual stimulation paradigm while the three types of signals were simultaneously recorded. The analysis started with a characterization of the MEG artifact caused by the SEEG equipment. Next, the average evoked activities were computed at the sensor level, and cortical source activations were estimated for both the EEG and MEG recordings; these were shown to be compatible with the spatiotemporal dynamics of the SEEG signals. In the average time-frequency domain, concordant patterns between the MEG/EEG and SEEG recordings were found below the 40 Hz level. Finally, a fine-grained coupling between the amplitudes of the three recording modalities was detected in the time domain, at the level of single evoked responses. Importantly, these correlations have shown a high level of spatial and temporal specificity. These findings provide a case for the ability of trimodal recordings (EEG, MEG, and SEEG) to reach a greater level of specificity in the investigation of brain signals and functions. PMID:24862073

Dubarry, Anne-Sophie; Badier, Jean-Michel; Trébuchon-Da Fonseca, Agnès; Gavaret, Martine; Carron, Romain; Bartolomei, Fabrice; Liégeois-Chauvel, Catherine; Régis, Jean; Chauvel, Patrick; Alario, F-Xavier; Bénar, Christian-G

2014-10-01

310

ALPHA OMEGA ALPHA National Honor Medical Society  

E-print Network

12/6/2012 1 ALPHA OMEGA ALPHA National Honor Medical Society www.alphaomegaalpha.org AA and Leadership The Alpha Omega Alpha honor medical society was organized in 1902 to "recognize and perpetuate Enter into a contract with patients and society Build a foundation of medical professionalism Define

311

IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. 55, NO. 3, MARCH 2008 1103 Array Response Kernels for EEG and MEG in  

E-print Network

for electroencephalography (EEG) and magnetoencephalography (MEG), assuming that a multilayer el- lipsoidal geometry signal, electroencephalography (EEG), ellipsoidal head model, magnetoencephalography (MEG), N20 response related to the localization of brain activity sources using electroencephalography (EEG) and magnetoen

Nehorai, Arye

312

[Detection of spikes in epileptic EEG based on Multiresolution Tsallis' entropy].  

PubMed

In this paper, the detection of the spikes in the epileptic EEG signal was studied based on Multiresolution Tsallis' entropy (MRET). First, EEG signals were decomposed into wavelet series, and then, at every scale, the abnormal spikes were distinguished from normal background EEG activities by using MRET. The analysis of 6 patients' EEG data showed that the abnormal epileptiform spikes in EEG can be accurately detected with this method, which opens up the perspectives of building up automatic detection devices for spikes in EEG. Compared with the Shannon entropy, the MRET provides one with more detailed information. PMID:11605493

Tang, S; Zhang, H; Zheng, C

2001-09-01

313

Potential for unreliable interpretation of EEG recorded with microelectrodes  

PubMed Central

SUMMARY PURPOSE Recent studies in epilepsy, cognition, and brain machine interfaces have shown the utility of recording intracranial EEG (iEEG) with greater spatial resolution. Many of these studies utilize microelectrodes connected to specialized amplifiers that are optimized for such recordings. We recently measured the impedances of several commercial microelectrodes and demonstrated that they will distort iEEG signals if connected to clinical EEG amplifiers commonly used in most centers. In this study we demonstrate the clinical implications of this effect and identify some of the potential difficulties in using microelectrodes. METHODS Human iEEG data were digitally filtered to simulate the signal recorded by a hybrid grid (2 macro- and 8 microelectrodes) connected to a standard EEG amplifier. The filtered EEG data were read by three trained epileptologists, and high frequency oscillations (HFOs) detected with a well-known algorithm. The filtering method was verified experimentally by recording an injected EEG signal in a saline bath with the same physical acquisition system used to generate the model. Several electrodes underwent scanning electron microscopy (SEM). KEY FINDINGS Macroelectrode recordings were unaltered compared to the source iEEG signal, but microelectrodes attenuated low frequencies. The attenuated signals were difficult to interpret: all three clinicians changed their clinical scoring of slowing and seizures when presented with the same data recorded on different electrodes. The HFO detection algorithm was oversensitive with microelectrodes, classifying many more HFOs than when the same data were recorded with macroelectrodes. In addition, during experimental recordings the microelectrodes produced much greater noise as well as large baseline fluctuations, creating sharply-contoured transients, and superimposed “false” HFOs. SEM of these microelectrodes demonstrated marked variability in exposed electrode surface area, lead fractures, and sharp edges. SIGNIFICANCE Microelectrodes should not be used with low impedance (< 1G?) amplifiers due to severe signal attenuation and variability that changes clinical interpretations. The current method of preparing microelectrodes can leave sharp edges and nonuniform amounts of exposed wire. Even when recorded with higher impedance amplifiers, microelectrode data is highly prone to artifacts that are difficult to interpret. Great care must be taken when analyzing iEEG from high impedance microelectrodes. PMID:23647099

Stacey, William C.; Kellis, Spencer; Greger, Bradley; Butson, Christopher R.; Patel, Paras R.; Assaf, Trevor; Mihaylova, Temenuzhka; Glynn, Simon

2013-01-01

314

SlimQuick™ - associated hepatotoxicity in a woman with alpha-1 antitrypsin heterozygosity  

PubMed Central

Green tea (Camellia sinensis)-associated hepatotoxicity is reported. However, the presence of alpha-1 antitrypsin MZ phenotype as a predisposing factor to green tea-associated drug-induced liver injury (DILI) is unknown. A previously healthy woman with alpha-1 antitrypsin MZ phenotype who took SlimQuick™, an herbal supplement containing green tea extract, developed severe hepatotoxicity requiring corticosteroid treatment. Green tea-associated hepatotoxicity is reviewed and alpha-1 antitrypsin MZ phenotype as a predisposing factor to green tea-associated DILI is discussed. Liver biopsy demonstrated marked inflammation with necrosis suggestive of toxic injury with diffuse alpha-1 antitrypsin globule deposition on immunostaining. Corticosteroid therapy resulted in rapid clinical improvement. Alpha-1 antitrypsin MZ phenotype may increase vulnerability to herbal hepatotoxicity. PMID:22567188

Weinstein, Douglas H; Twaddell, William S; Raufman, Jean-Pierre; Philosophe, Benjamin; Mindikoglu, Ayse L

2012-01-01

315

SlimQuick™ - associated hepatotoxicity in a woman with alpha-1 antitrypsin heterozygosity.  

PubMed

Green tea (Camellia sinensis)-associated hepatotoxicity is reported. However, the presence of alpha-1 antitrypsin MZ phenotype as a predisposing factor to green tea-associated drug-induced liver injury (DILI) is unknown. A previously healthy woman with alpha-1 antitrypsin MZ phenotype who took SlimQuick™, an herbal supplement containing green tea extract, developed severe hepatotoxicity requiring corticosteroid treatment. Green tea-associated hepatotoxicity is reviewed and alpha-1 antitrypsin MZ phenotype as a predisposing factor to green tea-associated DILI is discussed. Liver biopsy demonstrated marked inflammation with necrosis suggestive of toxic injury with diffuse alpha-1 antitrypsin globule deposition on immunostaining. Corticosteroid therapy resulted in rapid clinical improvement. Alpha-1 antitrypsin MZ phenotype may increase vulnerability to herbal hepatotoxicity. PMID:22567188

Weinstein, Douglas H; Twaddell, William S; Raufman, Jean-Pierre; Philosophe, Benjamin; Mindikoglu, Ayse L

2012-04-27

316

The Effects of l theanine on Alpha-Band Oscillatory Brain Activity During a VisuoSpatial Attention Task  

Microsoft Academic Search

Background\\/Objectives Ingestion of the non-proteinic amino acid l-theanine (?-glutamylethylamide) has been shown to influence oscillatory brain activity in the alpha band (8–14 Hz) in humans\\u000a during resting electroencephalographic (EEG) recordings and also during cognitive task performance. We have previously shown\\u000a that ingestion of a 250-mg dose of l-theanine significantly reduced tonic (background) alpha power during a demanding intersensory (auditory-visual) attentional cueing

Manuel Gomez-Ramirez; Simon P. Kelly; Jennifer L. Montesi; John J. Foxe

2009-01-01

317

EEG and Autonomic Responses During Performance of Matching and Non-Matching to Sample Working Memory Tasks with Emotional Content  

PubMed Central

Working memory (WM) is a memory system responsible for the temporary storage of information and its utilization in problem solving. The central executive is theorized as the controller of storage functions that support WM. Neurophysiological data suggest that electroencephalographic (EEG) theta and alpha oscillations in frontal and midline regions are involved in neural communication between the central executive and storage functions during WM performance. Emotion is known to modulate several memory systems, including WM, through central and peripheral pathways. However, the physiological effect (EEG; autonomic nervous activity) of emotion over WM are not well described. In this study we aimed to identify physiological responses related to emotional WM performance. EEG (21 channels), heart rate (HR), and galvanic skin response (GSR) recordings were obtained from 54 volunteers while performing delayed matching and non-matching to sample tasks (DMTS/DNMTS). Emotional and neutral pictures from the International Affective Picture System and geometric figures were used as stimuli. As expected, WM performance was accompanied by presence of theta (frontal and midline electrodes) and alpha power (parietal electrodes). Beta and gamma oscillations were concentrated in frontopolar and left temporal regions. The DNMTS task was accompanied by higher increases in beta power, HR, and GSR compared to the DMTS task. Correlation analyses showed a positive tendency for gamma in the Fp2 site, ratio of LF/HF and skin conductance in both tasks. The HR results indicate an inverse reaction related to parasympathetic and sympathetic nervous system during the performance of the tasks. Taken together, our results contribute to elucidate the complex interactions between central and autonomic nervous systems in the modulation of emotional WM tasks. PMID:22203795

Garcia, Ana; Uribe, Carlos Enrique; Tavares, Maria Clotilde H.; Tomaz, Carlos

2011-01-01

318

The Role of Personalization and Multiple EEG and Sound Features Selection in Real Time Sonification for Neurofeedback  

E-print Network

for extracting, processing and displaying Electroencephalography data (EEG) with different sonification strate (Neuroelectrics, 2013) now allow a low cost and wearable electroencephalography (EEG) sensing in out

319

Analysis of generalized interictal discharges using quantitative EEG.  

PubMed

Experimental evidence from animal models of the absence seizures suggests a focal source for the initiation of generalized spike-and-wave (GSW) discharges. Furthermore, clinical studies indicate that patients diagnosed with idiopathic generalized epilepsy (IGE) exhibit focal electroencephalographic abnormalities, which involve the thalamo-cortical circuitry. This circuitry is a key network that has been implicated in the initiation of generalized discharges, and may contribute to the pathophysiology of GSW discharges. Quantitative electroencephalogram (qEEG) analysis may be able to detect abnormalities associated with the initiation of GSW discharges. The objective of this study was to determine whether interictal GSW discharges exhibit focal characteristics using qEEG analysis. In this study, 75 EEG recordings from 64 patients were analyzed. All EEG recordings analyzed contained at least one GSW discharge. EEG recordings were obtained by a 22-channel recorder with electrodes positioned according to the international 10-20 system of electrode placement. EEG activity was recorded for 20 min including photic stimulation and hyperventilation. The EEG recordings were visually inspected, and the first unequivocally confirmed generalized spike was marked for each discharge. Three methods of source imaging analysis were applied: dipole source imaging (DSI), classical LORETA analysis recursively applied (CLARA), and equivalent dipole of independent components with cluster analysis. A total of 753 GSW discharges were identified and spatiotemporally analyzed. Source evaluation analysis using all three techniques revealed that the frontal lobe was the principal source of GSW discharges (70%), followed by the parietal and occipital lobes (14%), and the basal ganglia (12%). The main anatomical sources of GSW discharges were the anterior cingulate cortex (36%) and the medial frontal gyrus (23%). Source analysis did not reveal a common focal source of GSW discharges. However, there was a predominance of GSW discharges originating from the cingulate gyrus and the frontal lobe. PMID:25277883

da Silva Braga, Aline Marques; Fujisao, Elaine Keiko; Betting, Luiz Eduardo

2014-12-01

320

Ictal kissing with subdural EEG recording?  

PubMed Central

Purpose Ictal kissing has been described in the literature. Five cases were reported and associated with temporal lobe epilepsy lateralizing to the nondominant hemisphere. Methods A case of ictal kissing was identified. The aim was to demonstrate the clinical, clinical and electrophysiological features (as recorded by subdural electrodes). The surgical procedure, histopathology, and imaging data were reviewed and correlated with the literature. Results A 29-year-old right-handed female, who presented with ictal right hand left arm dystonic posturing, and lip smacking, was studied. The automatism was usually followed by prolonged emotional gestures and by hugging and kissing her relative and/or attendant nurse. Magnetic resonance imaging of the brain showed right small cortical and subcortical lesions of the right inferior frontal lobe with gliosis but without mass effect and normal-sized hippocampi. The PET scan showed hypometabolism of the right temporal lobe. Neuropsychological evaluation showed deficit in her nonverbal memory. The subdural electrodes showed high amplitude spikes over right mesial temporal lobe strips. The offsite of the ictal discharges was usually at the right frontal strips. Right standard temporal lobectomy with amygdalohippocampectomy and right inferior frontal lesionectomy were performed. The patient continued to be seizure-free for one year postoperatively. Conclusion Our case report supports with subdural EEG recording the findings of the few reported cases of ictal kissing behavior lateralized to the nondominant hemisphere. However, the affectionate kissing behavior was associated with spread of the epileptic discharges to the right frontal lobe.

Alsemari, Abdulaziz; Alotaibi, Faisal; Baz, Salah

2013-01-01

321

Genetic resources for phenotyping  

Technology Transfer Automated Retrieval System (TEKTRAN)

Phenotyping of structured populations, along with molecular genotyping, will be essential for marker development in peanut. This research is essential for making the peanut genome sequence and genomic tools useful to breeders because it makes the connection between genes, gene markers, genetic maps...

322

EEG Power Spectra of Adolescent Poor Readers.  

ERIC Educational Resources Information Center

Electroencephalographic power spectra were studied in two poor-reading adolescent groups (n=38), dysphonetic and phonetic. Significant Group x Hemisphere effects were found in the alpha and beta bands, with the phonetic group showing right greater than left asymmetry. Results suggest more circumscribed and mature processing in the phonetically…

Ackerman, Peggy T.; McPherson, W. Brian; Oglesby, D. Michael; Dykman, Roscoe A.

1998-01-01

323

Brain-computer interface design using alpha wave  

NASA Astrophysics Data System (ADS)

A brain-computer interface (BCI) is a novel communication system that translates brain activity into commands for a computer or other electronic devices. BCI system based on non-invasive scalp electroencephalogram (EEG) has become a hot research area in recent years. BCI technology can help improve the quality of life and restore function for people with severe motor disabilities. In this study, we design a real-time asynchronous BCI system using Alpha wave. The basic theory of this BCI system is alpha wave-block phenomenon. Alpha wave is the most prominent wave in the whole realm of brain activity. This system includes data acquisition, feature selection and classification. The subject can use this system easily and freely choose anyone of four commands with only short-time training. The results of the experiment show that this BCI system has high classification accuracy, and has potential application for clinical engineering and is valuable for further research.

Zhao, Hai-Bin; Wang, Hong; Liu, Chong; Li, Chun-Sheng

2009-12-01

324

Brain-computer interface design using alpha wave  

NASA Astrophysics Data System (ADS)

A brain-computer interface (BCI) is a novel communication system that translates brain activity into commands for a computer or other electronic devices. BCI system based on non-invasive scalp electroencephalogram (EEG) has become a hot research area in recent years. BCI technology can help improve the quality of life and restore function for people with severe motor disabilities. In this study, we design a real-time asynchronous BCI system using Alpha wave. The basic theory of this BCI system is alpha wave-block phenomenon. Alpha wave is the most prominent wave in the whole realm of brain activity. This system includes data acquisition, feature selection and classification. The subject can use this system easily and freely choose anyone of four commands with only short-time training. The results of the experiment show that this BCI system has high classification accuracy, and has potential application for clinical engineering and is valuable for further research.

Zhao, Hai-bin; Wang, Hong; Liu, Chong; Li, Chun-sheng

2010-01-01

325

IMPROVING SEPARABILITY OF EEG SIGNALS DURING MOTOR IMAGERY WITH AN EFFICIENT CIRCULAR LAPLACIAN  

E-print Network

in the scalp-recorded electroencephalo- graph (EEG). Depending on the part of the body imagined moving to the diffusion of the skull and the skin. To recover the focal activities, EEG potentials National ICT Australia

Hong,Seokhee

326

A Framework for Content-based Retrieval of EEG with Applications to Neuroscience and Beyond.  

PubMed

This paper introduces a prototype framework for content-based EEG retrieval (CBER). Like content-based image retrieval, the proposed framework retrieves EEG segments similar to the query EEG segment in a large database. Such retrieval of EEG can be used to assist data mining of brain signals by allowing researchers to understand the association between brain patterns, responses, and the environment. Retrieval might also be used to enhance the accuracy of Brain Computer Interface (BCI) systems by providing related samples for training. We present key components of CBER and explain how to handle the distinctive characteristics of EEG. To demonstrate the feasibility of the framework, we implemented a simple EEG database of about 37,000 samples from more than 100 subjects. We ran two retrieval scenarios with a set of EEG features and evaluation metrics. The results of finding similar subjects clearly demonstrate the potential of CBER in many EEG applications. PMID:24770451

Su, Kyungmin; Robbins, Kay A

2013-01-01

327

OPTIMAL SPATIAL FILTERING FOR AUDITORY STEADY-STATE RESPONSE DETECTION USING HIGH-DENSITY EEG  

E-print Network

steady-state responses (ASSRs) in the brain, which can be measured using electroencephalography (EEG adja- cent neurons in the brain and can be measured from the scalp using electroencephalography (EEG

328

Acquiring simultaneous EEG and functional MRIq Robin I. Goldmana,*, John M. Sternb  

E-print Network

Objective: Electroencephalography (EEG) is a challenge to record simultaneously with functional MRI (f rights reserved. Keywords: Electroencephalography; Functional MRI; Artifact; Brain mapping; Localization, Evoked response potential 1. Introduction Electroencephalography (EEG) has been a key tool in the study

Gabrieli, John

329

Sleep and EEG spectra in the pigeon ( Columba livia ) under baseline conditions and after sleep deprivation  

Microsoft Academic Search

Sleep in adult domestic pigeons was studied by continuous 24-h recording of the EEG, EMG and EOG. Vigilance states were scored on the basis of behavioral observations, visual scoring of the polygraph records, and EEG power spectra.

Irene Tobler; Alexander A. Borbély

1988-01-01

330

Textile Electrodes for EEG Recording — A Pilot Study  

PubMed Central

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

Löfhede, Johan; Seoane, Fernando; Thordstein, Magnus

2012-01-01

331

Nonlinear EEG Decoding Based on a Particle Filter Model  

PubMed Central

While the world is stepping into the aging society, rehabilitation robots play a more and more important role in terms of both rehabilitation treatment and nursing of the patients with neurological diseases. Benefiting from the abundant contents of movement information, electroencephalography (EEG) has become a promising information source for rehabilitation robots control. Although the multiple linear regression model was used as the decoding model of EEG signals in some researches, it has been considered that it cannot reflect the nonlinear components of EEG signals. In order to overcome this shortcoming, we propose a nonlinear decoding model, the particle filter model. Two- and three-dimensional decoding experiments were performed to test the validity of this model. In decoding accuracy, the results are comparable to those of the multiple linear regression model and previous EEG studies. In addition, the particle filter model uses less training data and more frequency information than the multiple linear regression model, which shows the potential of nonlinear decoding models. Overall, the findings hold promise for the furtherance of EEG-based rehabilitation robots. PMID:24949420

Hong, Jun

2014-01-01

332

Quantitative EEG patterns of differential in-flight workload  

NASA Technical Reports Server (NTRS)

Four test pilots were instrumented for in-flight EEG recordings using a custom portable recording system. Each flew six, two minute tracking tasks in the Calspan NT-33 experimental trainer at Edwards AFB. With the canopy blacked out, pilots used a HUD display to chase a simulated aircraft through a random flight course. Three configurations of flight controls altered the flight characteristics to achieve low, moderate, and high workload, as determined by normative Cooper-Harper ratings. The test protocol was administered by a command pilot in the back seat. Corresponding EEG and tracking data were compared off-line. Tracking performance was measured as deviation from the target aircraft and combined with control difficulty to achieve an estimate of 'cognitive workload'. Trended patterns of parietal EEG activity at 8-12 Hz were sorted according to this classification. In all cases, high workload produced a significantly greater suppression of 8-12 Hz activity than low workload. Further, a clear differentiation of EEG trend patterns was obtained in 80 percent of the cases. High workload produced a sustained suppression of 8-12 Hz activity, while moderate workload resulted in an initial suppression followed by a gradual increment. Low workload was associated with a modulated pattern lacking any periods of marked or sustained suppression. These findings suggest that quantitative analysis of appropriate EEG measures may provide an objective and reliable in-flight index of cognitive effort that could facilitate workload assessment.

Sterman, M. B.; Mann, C. A.; Kaiser, D. A.

1993-01-01

333

Is routine electroencephalography (EEG) a useful biomarker for pharmacoresistant epilepsy?  

PubMed

People with seizure disorders who have been treated at the Kork Epilepsy Center over a prolonged time period and who thus provide data concerning the chronic course of epilepsy were investigated in order to address the potential role of electroencephalography (EEG) as a biomarker for pharmacoresistant epilepsy. Clinical course and the corresponding findings from their first recorded EEG, their first EEG following appropriate treatment, and their last EEG were compared. Furthermore, we investigated if interictal epileptiform discharges (IEDs) differ in amplitude and morphology if recorded in long-term seizure-free patients. The early cessation of IEDs was a relatively good marker for a good prognosis, especially in idiopathic generalized epilepsies. However, persistent IEDs had no major impact on the long-term prognosis. We found no differences between IEDs in seizure-free patients or patients with ongoing seizures. Therefore, in our hands, routine EEG was not an appropriate biomarker for the prediction of pharmacoresistant epilepsy. Additional factors such as etiology and pathophysiology also need to be considered. PMID:23646974

Steinhoff, Bernhard J; Scholly, Julia; Dentel, Christel; Staack, Anke Maren

2013-05-01

334

Quantitative change of EEG and respiration signals during mindfulness meditation  

PubMed Central

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

2014-01-01

335

Object-based attentional selection modulates anticipatory alpha oscillations  

PubMed Central

Visual cortical alpha oscillations are involved in attentional gating of incoming visual information. It has been shown that spatial and feature-based attentional selection result in increased alpha oscillations over the cortical regions representing sensory input originating from the unattended visual field and task-irrelevant visual features, respectively. However, whether attentional gating in the case of object based selection is also associated with alpha oscillations has not been investigated before. Here we measured anticipatory electroencephalography (EEG) alpha oscillations while participants were cued to attend to foveal face or word stimuli, the processing of which is known to have right and left hemispheric lateralization, respectively. The results revealed that in the case of simultaneously displayed, overlapping face and word stimuli, attending to the words led to increased power of parieto-occipital alpha oscillations over the right hemisphere as compared to when faces were attended. This object category-specific modulation of the hemispheric lateralization of anticipatory alpha oscillations was maintained during sustained attentional selection of sequentially presented face and word stimuli. These results imply that in the case of object-based attentional selection—similarly to spatial and feature-based attention—gating of visual information processing might involve visual cortical alpha oscillations. PMID:25628554

Knakker, Balázs; Weiss, Béla; Vidnyánszky, Zoltán

2015-01-01

336

Seizure identification in the ICU using quantitative EEG displays(e–Pub ahead of print)  

PubMed Central

Objective: To evaluate the diagnostic accuracy of 2 quantitative EEG display tools, color density spectral array (CDSA) and amplitude-integrated EEG (aEEG), for seizure identification in the intensive care unit (ICU). Methods: A set of 27 continuous EEG recordings performed in pediatric ICU patients was transformed into 8-channel CDSA and aEEG displays. Three neurophysiologists underwent 2 hours of training to identify seizures using these techniques. They were then individually presented with a series of CDSA and aEEG displays, blinded to the raw EEG, and asked to mark any events suspected to be seizures. Their performance was compared to seizures identified on the underlying conventional EEG. Results: The 27 EEG recordings contained 553 discrete seizures over 487 hours. The median sensitivity for seizure identification across all recordings was 83.3% using CDSA and 81.5% using aEEG. However, among individual recordings, the sensitivity ranged from 0% to 100%. Factors reducing the sensitivity included low-amplitude, short, and focal seizures. False-positive rates were generally very low, with misidentified seizures occurring once every 17–20 hours. Conclusions: Both CDSA and aEEG demonstrate acceptable sensitivity and false-positive rates for seizure identification among critically ill children. Accuracy of these tools would likely improve during clinical use, when findings can be correlated in real-time with the underlying raw EEG. In the hands of neurophysiologists, CDSA and aEEG displays represent useful screening tools for seizures during continuous EEG monitoring in the ICU. The suitability of these tools for bedside use by ICU nurses and physicians requires further study. GLOSSARY aEEG = amplitude-integrated EEG; CDSA = color density spectral array; FFT = fast-Fourier transformation; ICU = intensive care unit. PMID:20861452

Stewart, C.P.; Otsubo, H.; Ochi, A.; Sharma, R.; Hutchison, J.S.; Hahn, C.D.

2010-01-01

337

System Level spatial-frequency EEG changes coincident with a 90-day cogntive-behavioral therapy program for couples in relationship distress.  

PubMed

Evaluating relationship intervention programs traditionally involves the use of self-report surveys or observational studies to assess changes in behavior. Instead, to investigate intervention-related changes in behavior, our study evaluates spatial-frequency electroencephalography (EEG) patterns from the brains of couples participating in an Imago Relationship workshop and 12 weeks of group counseling sessions lasting approximately 90 days. This explorative study recorded 32-channel EEGs from nine committed distressed couples prior to, during and immediately following the Imago Relationship Therapy program. A repeated measures t-Test approach was applied to investigate if significant group level brain pattern changes could be identified in key resting state networks in the brains of the participants that could be correlated with changes in relationship outcome. The study results show that significant reductions in EEG power in the alpha2, beta3 and gamma bands were evident in the averaged brain activity in the pre-frontal, frontal and temporal-parietal cortices that are anatomically associated with the frontal executive, default mode and salience networks of the human brain. Our current understanding of system level neural connectivity and network dynamics strongly indicates that each of these systems is integrally required in learning and implementing a complex communication process taught in the Imago intervention. Thus, a high degree of hemispheric lateralization is consistent with our understanding of language function and mood regulation in the brain and is consistent with recent research into the use of resting frontal EEG asymmetry as an indicator of behavioral changes in distressed couples undergoing a program for relationship improvement. Although preliminary, these results further indicate that the EEG is an inexpensive and easily quantifiable measure, and possibly predictor, of behavioral changes in response to a cognitive behavioral intervention. PMID:25274224

DuRousseau, Donald R; Beeton, Theresa A

2014-10-01

338

Towards a unified understanding of event-related changes in the EEG: the firefly model of synchronization through cross-frequency phase modulation.  

PubMed

Although event-related potentials (ERPs) are widely used to study sensory, perceptual and cognitive processes, it remains unknown whether they are phase-locked signals superimposed upon the ongoing electroencephalogram (EEG) or result from phase-alignment of the EEG. Previous attempts to discriminate between these hypotheses have been unsuccessful but here a new test is presented based on the prediction that ERPs generated by phase-alignment will be associated with event-related changes in frequency whereas evoked-ERPs will not. Using empirical mode decomposition (EMD), which allows measurement of narrow-band changes in the EEG without predefining frequency bands, evidence was found for transient frequency slowing in recognition memory ERPs but not in simulated data derived from the evoked model. Furthermore, the timing of phase-alignment was frequency dependent with the earliest alignment occurring at high frequencies. Based on these findings, the Firefly model was developed, which proposes that both evoked and induced power changes derive from frequency-dependent phase-alignment of the ongoing EEG. Simulated data derived from the Firefly model provided a close match with empirical data and the model was able to account for i) the shape and timing of ERPs at different scalp sites, ii) the event-related desynchronization in alpha and synchronization in theta, and iii) changes in the power density spectrum from the pre-stimulus baseline to the post-stimulus period. The Firefly Model, therefore, provides not only a unifying account of event-related changes in the EEG but also a possible mechanism for cross-frequency information processing. PMID:23049827

Burgess, Adrian P

2012-01-01

339

Towards a Unified Understanding of Event-Related Changes in the EEG: The Firefly Model of Synchronization through Cross-Frequency Phase Modulation  

PubMed Central

Although event-related potentials (ERPs) are widely used to study sensory, perceptual and cognitive processes, it remains unknown whether they are phase-locked signals superimposed upon the ongoing electroencephalogram (EEG) or result from phase-alignment of the EEG. Previous attempts to discriminate between these hypotheses have been unsuccessful but here a new test is presented based on the prediction that ERPs generated by phase-alignment will be associated with event-related changes in frequency whereas evoked-ERPs will not. Using empirical mode decomposition (EMD), which allows measurement of narrow-band changes in the EEG without predefining frequency bands, evidence was found for transient frequency slowing in recognition memory ERPs but not in simulated data derived from the evoked model. Furthermore, the timing of phase-alignment was frequency dependent with the earliest alignment occurring at high frequencies. Based on these findings, the Firefly model was developed, which proposes that both evoked and induced power changes derive from frequency-dependent phase-alignment of the ongoing EEG. Simulated data derived from the Firefly model provided a close match with empirical data and the model was able to account for i) the shape and timing of ERPs at different scalp sites, ii) the event-related desynchronization in alpha and synchronization in theta, and iii) changes in the power density spectrum from the pre-stimulus baseline to the post-stimulus period. The Firefly Model, therefore, provides not only a unifying account of event-related changes in the EEG but also a possible mechanism for cross-frequency information processing. PMID:23049827

Burgess, Adrian P.

2012-01-01

340

Frontal EEG asymmetry moderates the effects of stressful life events on internalizing symptoms in children at familial-risk for depression  

PubMed Central

This study examined whether frontal alpha electroencephalographic (EEG) asymmetry moderates the association between stressful life events and depressive symptoms in children at familial-risk for depression. Participants included 135 children ages 6 to 13, whose mothers had either a history of depression or no history of major psychiatric conditions. Frontal EEG was recorded while participants watched emotion-eliciting films. Symptoms and stressful life events were obtained via the Child Behavior Check List and a clinical interview, respectively. High-risk children displayed greater relative right lateral frontal activation (F7/F8) than their low-risk peers during the films. For high-risk children, greater relative left lateral frontal activation moderated the association between stressful life events and internalizing symptoms. Specifically, greater relative left lateral frontal activation mitigated the effects of stress in at-risk children. PMID:22220930

Lopez-Duran, Nestor L.; Nusslock, Robin; George, Charles; Kovacs, Maria

2011-01-01

341

Acute effects of MDMA (3,4-methylenedioxymethamphetamine) on EEG oscillations: alone and in combination with ethanol or THC (delta-9-tetrahydrocannabinol)  

PubMed Central

Rationale Typical users of 3,4-methylenedioxymethamphetamine (MDMA or “ecstasy”) are polydrug users, combining MDMA with alcohol or cannabis [most active compound: delta-9-tetrahydrocannabinol (THC)]. Objectives The aim of the present study was to investigate whether co-administration of alcohol or THC with MDMA differentially affects ongoing electroencephalogram (EEG) oscillations compared to the administration of each drug alone. Methods In two separate experiments, 16 volunteers received four different drug conditions: (1) MDMA (100 mg); (2) alcohol clamp (blood alcohol concentration?=?0.6‰) or THC (inhalation of 4, 6 and 6 mg, interval of 1.5 h); (3) MDMA in combination with alcohol or THC; and (4) placebo. Before and after drug administration, electroencephalography was recorded during an eyes closed resting state. Results Theta and alpha power increased after alcohol intake compared to placebo and reduced after MDMA intake. No interaction between alcohol and MDMA was found. Significant MDMA × THC effects for theta and lower-1-alpha power indicated that the power attenuation after the combined intake of MDMA and THC was less than the sum of each drug alone. For the lower-2-alpha band, the intake of MDMA or THC alone did not significantly affect power, but the intake of combined MDMA and THC significantly decreased lower-2-alpha power. Conclusions The present findings indicate that the combined intake of MDMA and THC, but not of MDMA and alcohol, affects ongoing EEG oscillations differently than the sum of either one drug alone. Changes in ongoing EEG oscillations may be related to the impaired task performance that has often been reported after drug intake. PMID:20924751

Dumont, Glenn J. H.; van Gerven, Joop M. A.; Buitelaar, Jan K.; Verkes, Robbert-Jan

2010-01-01

342

EEG Estimates of Cognitive Workload and Engagement Predict Math Problem Solving Outcomes  

ERIC Educational Resources Information Center

In the present study, the authors focused on the use of electroencephalography (EEG) data about cognitive workload and sustained attention to predict math problem solving outcomes. EEG data were recorded as students solved a series of easy and difficult math problems. Sequences of attention and cognitive workload estimates derived from the EEG

Beal, Carole R.; Galan, Federico Cirett

2012-01-01

343

The Effects of EEG Biofeedback Training on Hyperactive and/or Learning Disabled Children.  

ERIC Educational Resources Information Center

The literature review presents an explanation of biofeedback and a critical evaluation of the research pertaining to electroencephalographic (EEG) biofeedback training for the hyperactive and/or learning disabled child. Three hypotheses are examined: whether EEG biofeedback training is efficacious; whether EEG biofeedback training is more…

Kassel, Steve

344

EEG denoising with a recurrent quantum neural network for a brain-computer interface  

Microsoft Academic Search

Brain-computer interface (BCI) technology is a means of communication that allows individuals with severe movement disability to communicate with external assistive devices using the electroencephalogram (EEG) or other brain signals. This paper presents an alternative neural information processing architecture using the Schrwave equation (SWE) for enhancement of the raw EEG signal. The raw EEG signal obtained during the motor imagery

Vaibhav Gandhi; Vipul Arora; Laxmidhar Behera; Girijesh Prasad; Damien Coyle; TM McGinnity

2011-01-01

345

Canonical decomposition of ictal scalp EEG reliably detects the seizure onset zone  

Microsoft Academic Search

Long-term electroencephalographic (EEG) recordings are important in the presurgical evaluation of refractory partial epilepsy for the delineation of the irritative and ictal onset zones. In this paper we introduce a new algorithm for an automatic, fast and objective localizing of the ictal onset zone in ictal EEG recordings. We extracted the potential distribution of the ictal activity from EEG using

M. De Vos; A. Vergult; L. De Lathauwer; W. De Clercq; S. Van Huffel; P. Dupont; A. Palmini; W. Van Paesschen

2007-01-01

346

Alpha-1 Antitrypsin Deficiency  

MedlinePLUS

... page from the NHLBI on Twitter. What Is Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (an-tee-TRIP-sin) deficiency, or ... deficiency as it relates to lung disease. Overview Alpha-1 antitrypsin, also called AAT, is a protein ...

347

Liver and Alpha-1  

MedlinePLUS

... Resources CSL Behring Grifols The mission of the Alpha-1 Foundation is to provide the leadership and ... more information, visit: www.alpha-1foundation.org. The Alpha-1 Association is the leading national patient membership ...

348

Alpha One Foundation  

MedlinePLUS

What is Alpha-1? A lpha-1 Antitrypsin Deficiency (Alpha-1) is a genetic (inherited) condition – it is passed from parents to their children through their genes. Alpha-1 may result in serious lung disease in ...

349

An EEG (electroencephalogram) recording system with carbon wire electrodes for simultaneous EEG-fMRI (functional magnetic resonance imaging) recording  

PubMed Central

Simultaneous EEG-fMRI (Electroencephalography-functional Magnetic Resonance Imaging) recording provides a means for acquiring high temporal resolution electrophysiological data and high spatial resolution metabolic data of the brain in the same experimental runs. Carbon wire electrodes (not metallic EEG electrodes with carbon wire leads) are suitable for simultaneous EEG-fMRI recording, because they cause less RF (radio-frequency) heating and susceptibility artifacts than metallic electrodes. These characteristics are especially desirable for recording the EEG in high field MRI scanners. Carbon wire electrodes are also comfortable to wear during long recording sessions. However, carbon electrodes have high electrode-electrolyte potentials compared to widely used Ag/AgCl (silver/silver-chloride) electrodes, which may cause slow voltage drifts. This paper introduces a prototype EEG recording system with carbon wire electrodes and a circuit that suppresses the slow voltage drift. The system was tested for the voltage drift, RF heating, susceptibility artifact, and impedance, and was also evaluated in a simultaneous ERP (event-related potential)-fMRI experiment. PMID:18588913

Negishi, Michiro; Abildgaard, Mark; Laufer, Ilan; Nixon, Terry; Constable, Robert Todd

2008-01-01

350

Multi-dipole EEG source localization using particle swarm optimization.  

PubMed

The multi-dipole EEG source localization problem is (usually) highly nonlinear with a non-convex cost function. Moreover, the gray matter tissue is located in several disjunct regions in the head which leads to a non-continuous solution space. For solving this problem an efficient algorithm which can handle multi-source activities is needed. In this paper, a modified particle swarm optimization (MPSO) method is proposed to solve the multi-dipole EEG source localization. The method is tested on synthetic EEG signals generated from two strong active sources and a noisy background source. The results show that using the new method is a reliable choice when we deal with a strong multi-active source scenario, in which a single dipole source localization may fail. PMID:24111195

Shirvany, Yazdan; Edelvik, Fredrik; Persson, Mikael

2013-01-01

351

Classification of independent components of EEG into multiple artifact classes.  

PubMed

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 found that automatic separation of multiple artifact classes is possible with a small feature set. Our method can reduce manual workload and allow for the selective removal of artifact classes. Identifying artifacts during EEG recording may be used to instruct subjects to refrain from activity causing them. PMID:25048104

Frølich, Laura; Andersen, Tobias S; Mørup, Morten

2015-01-01

352

Dynamic dictionary for combined EEG compression and seizure detection.  

PubMed

A novel technique for real-time electroencephalogram (EEG) compression is proposed in this paper. This technique makes use of the redundancy between the different frequency subbands present in EEG segments of one channel. It uses discrete wavelet transform (DWT) and dynamic reference lists to compute and send the decorrelated subband coefficients. Set partitioning in hierarchical trees (SPIHT) is also used as source coder. Experimental results showed that the proposed method can not only compress EEG channels in one dimension (1- D), but also detect seizure-like activity. A diagnostics-oriented performance assessment was performed to evaluate the performance of both the compression and detection capabilities of the proposed method. In this paper, we show that the algorithm can positively detect seizure sections in the recordings at bitrates down to 2 bits per sample. PMID:24403423

Daou, Hoda; Labeau, Fabrice

2014-01-01

353

HZI systems for EEG parametrization and classification of psychotropic drugs.  

PubMed

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. PMID:419164

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

1979-01-01

354

Sources of abnormal EEG activity in brain infarctions.  

PubMed

EEGs from 16 patients with stroke in three different stages of evolution were recorded. EEG sources were calculated every 0.39 Hz by frequency domain VARETA. The main source was within the delta band in 2 out of 4 chronic patients, and in 67% of the patients in the acute or subacute stages when edema (cytotoxic or vasogenic) was present. Moreover, all patients showed abnormal activity in the theta band. Sources of abnormal activity in cortical or corticosubcortical infarcts were located in the cortex, surrounding the lesion. At the site of the infarct, a decrease of EEG power was observed. Sources of abnormal theta power coincided with edema and/or ischemic penumbra. PMID:11056837

Fernández-Bouzas, A; Harmony, T; Fernández, T; Silva-Pereyra, J; Valdés, P; Bosch, J; Aubert, E; Casián, G; Otero Ojeda, G; Ricardo, J; Hernández-Ballesteros, A; Santiago, E

2000-10-01

355

Mining EEG-fMRI using independent component analysis.  

PubMed

Independent component analysis (ICA) is a multivariate approach that has become increasingly popular for analyzing brain imaging data. In contrast to the widely used general linear model (GLM) that requires the user to parameterize the brain's response to stimuli, ICA allows the researcher to explore the factors that constitute the data and alleviates the need for explicit spatial and temporal priors about the responses. In this paper, we introduce ICA for hemodynamic (fMRI) and electrophysiological (EEG) data processing, and one of the possible extensions to the population level that is available for both data types. We then selectively review some work employing ICA for the decomposition of EEG and fMRI data to facilitate the integration of the two modalities to provide an overview of what is available and for which purposes ICA has been used. An optimized method for symmetric EEG-fMRI decomposition is proposed and the outstanding challenges in multimodal integration are discussed. PMID:19223007

Eichele, Tom; Calhoun, Vince D; Debener, Stefan

2009-07-01

356

EEG predictors of covert vigilant attention  

NASA Astrophysics Data System (ADS)

Objective. The present study addressed the question whether neurophysiological signals exhibit characteristic modulations preceding a miss in a covert vigilant attention task which mimics a natural environment in which critical stimuli may appear in the periphery of the visual field. Approach. Subjective, behavioural and encephalographic (EEG) data of 12 participants performing a modified Mackworth Clock task were obtained and analysed offline. The stimulus consisted of a pointer performing regular ticks in a clockwise sequence across 42 dots arranged in a circle. Participants were requested to covertly attend to the pointer and press a response button as quickly as possible in the event of a jump, a rare and random event. Main results. Significant increases in response latencies and decreases in the detection rates were found as a function of time-on-task, a characteristic effect of sustained attention tasks known as the vigilance decrement. Subjective sleepiness showed a significant increase over the duration of the experiment. Increased activity in the ?-frequency range (8-14 Hz) was observed emerging and gradually accumulating 10 s before a missed target. Additionally, a significant gradual attenuation of the P3 event-related component was found to antecede misses by 5 s. Significance. The results corroborate recent findings that behavioural errors are presaged by specific neurophysiological activity and demonstrate that lapses of attention can be predicted in a covert setting up to 10 s in advance reinforcing the prospective use of brain-computer interface (BCI) technology for the detection of waning vigilance in real-world scenarios. Combining these findings with real-time single-trial analysis from BCI may pave the way for cognitive states monitoring systems able to determine the current, and predict the near-future development of the brain's attentional processes.

Martel, Adrien; Dähne, Sven; Blankertz, Benjamin

2014-06-01

357

Modifications of EEG power spectra in mesial temporal lobe during n-back tasks of increasing difficulty. A sLORETA study  

PubMed Central

The n-back task is widely used to investigate the neural basis of Working Memory (WM) processes. The principal aim of this study was to explore and compare the EEG power spectra during two n-back tests with different levels of difficulty (1-back vs. 3-back). Fourteen healthy subjects were enrolled (seven men and seven women, mean age 31.21 ± 7.05 years, range: 23–48). EEG was recorded while performing the N-back test, by means of 19 surface electrodes referred to joint mastoids. EEG analysis were conducted by means of the standardized Low Resolution brain Electric Tomography (sLORETA) software. The statistical comparison between EEG power spectra in the two conditions was performed using paired t-statistics on the coherence values after Fisher's z transformation available in the LORETA program package. The frequency bands considered were: delta (0.5–4 Hz); theta (4.5–7.5 Hz); alpha (8–12.5 Hz); beta (13–30 Hz); gamma (30.5–100 Hz). Significant changes occurred in the delta band: in the 3-back condition an increased delta power was localized in a brain region corresponding to the Brodmann Area (BA) 28 in the left posterior entorhinal cortex (T = 3.112; p < 0.05) and in the BA 35 in the left perirhinal cortex in the parahippocampal gyrus (T = 2.876; p < 0.05). No significant differences were observed in the right hemisphere and in the alpha, theta, beta, and gamma frequency bands. Our results indicate that the most prominent modification induced by the increased complexity of the task occur in the mesial left temporal lobe structures. PMID:23565085

Imperatori, Claudio; Farina, Benedetto; Brunetti, Riccardo; Gnoni, Valentina; Testani, Elisa; Quintiliani, Maria I.; Del Gatto, Claudia; Indraccolo, Allegra; Contardi, Anna; Speranza, Anna M.; Della Marca, Giacomo

2013-01-01

358

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

PubMed Central

Although efforts to characterize human movement through electroencephalography (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 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 Effort qualities 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 quality (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 quality 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. PMID:24782734

Cruz-Garza, Jesus G.; Hernandez, Zachery R.; Nepaul, Sargoon; Bradley, Karen K.; Contreras-Vidal, Jose L.

2014-01-01

359

Diurnal variation in the quantitative EEG in healthy adult volunteers  

PubMed Central

Aims To define the change in power in standard waveband frequencies of quantitative cortical electroencephalogram (EEG) data over a 24 h period, in a drug free representative healthy volunteer population. Methods This was an open, non randomised study in which 18 volunteers (9 male and 9 female) were studied on 1 study day, over a 24 h period. Volunteers had a cortical EEG recording taken at 0, 2, 4, 6, 8, 10, 12, 16 and 24 h. Each recording lasted for 6 min (3 min eyes open, 3 min eyes closed). All EEG recordings were taken in a quietened ward environment with the curtains drawn round the bed and the volunteer supine. During the 3 min eyes open, volunteers were asked to look at a red circle on a screen at the foot of the bed, and refrain from talking. Results Plots produced of geometric mean power by time of the standard wave band frequencies gave some indication of a circadian rhythm over the 24 h period for ? (4.75–6.75 Hz), ?1 (7.0–9.5 Hz) and ?1 (12.75–18.50 Hz) wavebands. Mixed models were fitted to both the eyes open and eyes closed data which confirmed a change in mean waveband power with time with statistical significance at the conventional 5% level (P < 0.05). Conclusions These data indicate the presence of a diurnal variation in the cortical quantitative EEG. They support the use of a placebo control group when designing clinical trials which utilize quantitative EEG to screen for central nervous system (CNS) activity of pharmaceutical agents, to control for the confounding variable of time of day at which the EEG recordings were made. PMID:10886113

Cummings, L; Dane, A; Rhodes, J; Lynch, P; Hughes, A M

2000-01-01

360

Signal distortion from microelectrodes in clinical EEG acquisition systems  

NASA Astrophysics Data System (ADS)

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 (<60 Hz), which caused significant changes in amplitude, phase, variance and spectral band power. In contrast, there were only minimal changes to the signal content for frequencies above 100 Hz. In order to minimize distortion with microelectrodes, we determined that an acquisition system should have an input impedance of at least 1 G?, 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.

Stacey, William C.; Kellis, Spencer; Patel, Paras R.; Greger, Bradley; Butson, Christopher R.

2012-10-01

361

EEG with triphasic waves in Borrelia burgdorferi meningoencephalitis.  

PubMed

We describe a case of encephalopathy in which the clinical picture and triphasic waves in the EEG indicated a metabolic cause. However, the illness was caused by neuroborreliosis. The occurrence of triphasic waves in the EEG is a strong evidence of metabolic encephalopathy, but triphasic waves are not specific for metabolic encephalopathy. Triphasic waves have been described in a number of non-metabolic encephalopaties and structural brain lesions. To our knowledge, this is the first report of triphasic waves in Borrelia burgdorferi meningoencephalitis. PMID:17661801

Eriksson, B; Wictor, L

2007-08-01

362

Color combinations of visual display terminal (VDT) icon on user preferences and EEG response.  

PubMed

This study explored the effects of color combinations and polarity on user preferences and EEG responses using an icon design for a visual display terminal. 72 college students (M=24.5 yr., SD=2.3 yr.) were tested. The seven color combinations of top 16% with rating scores (5-point scale) over 3.60 almost always included black or white as a target or background, including white-on-black, red-on-black, yellow-on-black, blue-on-white, and black-on-white; the other two preferred color combinations were yellow-on-blue and blue-on-yellow. The eight color combinations of the bottom 16% with rating scores under 2.38 almost always included green, turquoise, or purple as a target or background. Negative image polarity (higher luminance color image shown on a lower luminance color background) was preferred over positive image polarity (lower luminance color image shown on a higher luminance color background) by the subjects. The theta and alpha band power in the right hemisphere were greater than those in the left hemisphere during the experiment. There seemed to be no linear correlation between the rating scores of subjective preferences and brain wave power of theta and alpha bands, so the possibility of using brain wave power to measure subjective preference is questionable. PMID:20499552

Ko, Ya-Hsien; Shen, I-Hsuan; Lee, Der-Song

2010-04-01

363

Phase shifts in alpha-frequency rhythm detected in electroencephalograms influence reaction time.  

PubMed

Although the phase shifts in ongoing oscillations seen in electroencephalograms (EEGs) and magnetoencephalograms are an important factor in discussions of phase dynamics, such as synchrony and reset, few studies have focused specifically on the phase shift. Here we investigate the relationship between phase shifts in alpha-frequency rhythms and reaction times during a visual simple reaction task by applying our previously described method (Naruse et al., 2013), which enables detection of phase shifts from a single EEG trial. In the left, parietal, and occipital areas, the reaction times in the trials in which phase shifts were detected before the button press were significantly longer than in those in which phase shifts were not so detected. These results indicate that phase shifts in the alpha and mu rhythms relate to variability in reaction times. PMID:25150125

Naruse, Yasushi; Takiyama, Ken; Okada, Masato; Umehara, Hiroaki; Sakaguchi, Yutaka

2015-02-01

364

Alpha activity and cardiac correlates: three types of relationships during nocturnal sleep  

Microsoft Academic Search

Objective: We examined simultaneously alpha activity and cardiac changes during nocturnal sleep, in order to differentiate non-rapid eye movement (NREM) sleep, REM sleep, and intra-sleep awakening.Methods: Ten male subjects displaying occasionally spontaneous intra-sleep awakenings underwent EEG and cardiac recordings during one experimental night. The heart rate and heart rate variability were calculated over 5 min periods. Heart rate variability was

J Ehrhart; M Toussaint; C Simon; C Gronfier; R Luthringer; G Brandenberger

2000-01-01

365

Shaping Functional Architecture by Oscillatory Alpha Activity: Gating by Inhibition  

PubMed Central

In order to understand the working brain as a network, it is essential to identify the mechanisms by which information is gated between regions. We here propose that information is gated by inhibiting task-irrelevant regions, thus routing information to task-relevant regions. The functional inhibition is reflected in oscillatory activity in the alpha band (8–13?Hz). From a physiological perspective the alpha activity provides pulsed inhibition reducing the processing capabilities of a given area. Active processing in the engaged areas is reflected by neuronal synchronization in the gamma band (30–100?Hz) accompanied by an alpha band decrease. According to this framework the brain could be studied as a network by investigating cross-frequency interactions between gamma and alpha activity. Specifically the framework predicts that optimal task performance will correlate with alpha activity in task-irrelevant areas. In this review we will discuss the empirical support for this framework. Given that alpha activity is by far the strongest signal recorded by EEG and MEG, we propose that a major part of the electrophysiological activity detected from the working brain reflects gating by inhibition. PMID:21119777

Jensen, Ole; Mazaheri, Ali

2010-01-01

366

Pharmaco-EEG: A Study of Individualized Medicine in Clinical Practice.  

PubMed

Pharmaco-electroencephalography (Pharmaco-EEG) studies using clinical EEG and quantitative EEG (qEEG) technologies have existed for more than 4 decades. This is a promising area that could improve psychotropic intervention using neurological data. One of the objectives in our clinical practice has been to collect EEG and quantitative EEG (qEEG) data. In the past 5 years, we have identified a subset of refractory cases (n = 386) found to contain commonalities of a small number of electrophysiological features in the following diagnostic categories: mood, anxiety, autistic spectrum, and attention deficit disorders, Four abnormalities were noted in the majority of medication failure cases and these abnormalities did not appear to significantly align with their diagnoses. Those were the following: encephalopathy, focal slowing, beta spindles, and transient discharges. To analyze the relationship noted, they were tested for association with the assigned diagnoses. Fisher's exact test and binary logistics regression found very little (6%) association between particular EEG/qEEG abnormalities and diagnoses. Findings from studies of this type suggest that EEG/qEEG provides individualized understanding of pharmacotherapy failures and has the potential to improve medication selection. PMID:25420624

Swatzyna, Ronald J; Kozlowski, Gerald P; Tarnow, Jay D

2014-11-23

367

Prospects for clinical applications of transcranial magnetic stimulation and real-time EEG in epilepsy.  

PubMed

Recent advances in methods for transcranial magnetic stimulation (TMS) enable its coupling to real-time EEG (TMS-EEG). Although TMS-EEG is applied largely in neurophysiology research, there are prospects for its use in clinical TMS practice, particularly in epilepsy where EEG is already in wide use, and where TMS is emerging as a diagnostic and therapeutic tool. In diagnostic applications, TMS-EEG may provide a useful measure of cortical excitability at baseline or after antiepileptic treatment. For therapeutic purposes, TMS-EEG may be of use in selection of appropriate TMS strength outside of the motor cortex where the threshold for cortical activation is more apparent with the aid of EEG. In other realistic clinical applications, TMS-EEG may be of use in real-time monitoring for epileptiform activity in vulnerable populations where TMS may trigger seizures, or as a component of a responsive neurostimulation setup in which TMS timing is determined by underlying EEG activity. Future trials and evolution of TMS-EEG methods are likely to provide answers as to the actual clinical value of TMS-EEG. PMID:19921417

Rotenberg, Alexander

2010-01-01

368

MRI with and without a high-density EEG cap-what makes the difference?  

PubMed

Besides the benefit of combining electroencephalography (EEG) and magnetic resonance imaging (MRI), much effort has been spent to develop algorithms aimed at successfully cleaning the EEG data from MRI-related gradient and ballistocardiological artifacts. However, there are also studies showing a negative influence of the EEG on MRI data quality. Therefore, in the present study, we focused for the first time on the influence of the EEG on morphometric measurements of T1-weighted MRI data (voxel- and surfaced-based morphometry). Here, we demonstrate a strong influence of the EEG on cortical thickness, surface area, and volume as well as subcortical volumes due to local EEG-related inhomogeneities of the static magnetic (B0) and the gradient field (B1). In a second step, we analyzed the signal-to-noise ratios for both the anatomical and the functional data when recorded simultaneously with EEG and MRI and compared them to the ratios of the MRI data without simultaneous EEG measurements. These analyses revealed consistently lower signal-to-noise ratios for anatomical as well as functional MRI data during simultaneous EEG registration. In contrast, further analyses of T2*-weighted images provided reliable results independent of whether including the individuals' T1-weighted image with or without the EEG cap in the fMRI preprocessing stream. Based on our findings, we strongly recommend against using the structural images obtained during simultaneous EEG-MRI recordings for further anatomical data analysis. PMID:25482268

Klein, Carina; Hänggi, Jürgen; Luechinger, Roger; Jäncke, Lutz

2015-02-01

369

EEG findings in chlor-alkali workers subjected to low long term exposure to mercury vapour.  

PubMed Central

The cerebral effect of long term (mean 15.6, SD 8.9 years) and low (about 25 micrograms/m3 air) exposure to mercury vapour was studied in a group of 41 workers in a chlor-alkali plant and in a group of matched referents by electroencephalography (EEG). In the visually interpreted EEGs only a tendency for an increased number of EEG abnormalities, especially focal ones, could be seen in the exposed subjects. In the computerised EEG (cEEG), however, the exposed workers had significantly slower and more attenuated EEGs than the referants. This difference was most prominent in the occipital region, became milder parietally, and was almost absent frontally. Our results suggest that cEEG may show early effects on the brain of exposure to mercury vapour. PMID:2818969

Piikivi, L; Tolonen, U

1989-01-01

370

Automatic detection of epileptic seizures in long-term EEG records.  

PubMed

Epilepsy is a neurological disorder which affects nearly 1.5% of the world?s total population. Trained physicians and neurologists visually scan the long-term electroencephalographic (EEG) records to identify epileptic seizures. It generally requires many hours to interpret the data. Therefore, tools for quick detection of seizures in long-term EEG records are very useful. This study proposes an algorithm to help detect seizures in long-term iEEG based on low computational costs methods using Spectral Power and Wavelet analysis. The detector was tested on 21 invasive intracranial EEG (iEEG) records. A sensitivity of 85.39% was achieved. The results indicate that the proposed method detects epileptic seizures in long-term iEEG records successfully. Moreover, the algorithm does not require long processing time due to its simplicity. This feature will allow significant time reduction of the visual inspection of iEEG records performed by the specialists. PMID:25531725

Garcés Correa, Agustina; Orosco, Lorena; Diez, Pablo; Laciar, Eric

2015-02-01

371

Centrotemporal spikes during NREM sleep: The promoting action of thalamus revealed by simultaneous EEG and fMRI coregistration?  

PubMed Central

Benign childhood epilepsy with centrotemporal spikes (BECTS) has been investigated through EEG–fMRI with the aim of localizing the generators of the epileptic activity, revealing, in most cases, the activation of the sensory–motor cortex ipsilateral to the centrotemporal spikes (CTS). In this case report, we investigated the brain circuits hemodynamically involved by CTS recorded during wakefulness and sleep in one boy with CTS and a language disorder but without epilepsy. For this purpose, the patient underwent EEG–fMRI coregistration. During the “awake session”, fMRI analysis of right-sided CTS showed increments of BOLD signal in the bilateral sensory–motor cortex. During the “sleep session”, BOLD increments related to right-sided CTS were observed in a widespread bilateral cortical–subcortical network involving the thalamus, basal ganglia, sensory–motor cortex, perisylvian cortex, and cerebellum. In this patient, who fulfilled neither the diagnostic criteria for BECTS nor that for electrical status epilepticus in sleep (ESES), the transition from wakefulness to sleep was related to the involvement of a widespread cortical–subcortical network related to CTS. In particular, the involvement of a thalamic–perisylvian neural network similar to the one previously observed in patients with ESES suggests a common sleep-related network dysfunction even in cases with milder phenotypes without seizures. This finding, if confirmed in a larger cohort of patients, could have relevant therapeutic implication.

Mirandola, Laura; Cantalupo, Gaetano; Vaudano, Anna Elisabetta; Avanzini, Pietro; Ruggieri, Andrea; Pisani, Francesco; Cossu, Giuseppe; Tassinari, Carlo Alberto; Nichelli, Paolo Frigio; Benuzzi, Francesca; Meletti, Stefano

2013-01-01

372

alpha-Thalassaemia in the population of Cyprus.  

PubMed

We have determined the alpha-thalassaemia (alpha-thal) determinants in 78 patients with Hb H disease from Cyprus; 25 were Turkish Cypriots and 53 were Greek Cypriots. Four deletional and three non-deletional alpha-thal alleles were present; the -alpha(3.7 kb) alpha-thal-2 and the --MED-I alpha-thal-1 were most frequently seen; --MED-II and -(alpha)20.5 deletions occurred at considerably lower frequencies. About 15% of all chromosomes carried a non-deletional alpha-thal-2 allele; of these the 5 nucleotide (nt) deletion at the first intervening sequence (IVS-I) donor splice site was present in approximately 8% of all chromosomes. Two types of polyadenylation signal (poly A) mutations were observed. No striking frequency differences were seen between Greek and Turkish Cypriot patients. Combinations of the various types of alpha-thal resulted in eight different forms of Hb H disease. The phenotypes were comparable except for great variations in the level of Hb H which was highest (average approximately 22%) in the 12 patients with the alpha 5nt alpha/--MED-I combination. One patient with the same form of Hb H disease but with an additional beta-thal (IVS-I-110,G-->A) heterozygosity had a most severe microcytosis and hypochromia with < 1% Hb H. Variations in the level of Hb H might correlate with the severity of the disease, although this was not evident from the haematological data. PMID:7734346

Baysal, E; Kleanthous, M; Bozkurt, G; Kyrri, A; Kalogirou, E; Angastiniotis, M; Ioannou, P; Huisman, T H

1995-03-01

373

A strong parietal hub in the small-world network of coloured-hearing synaesthetes during resting state EEG.  

PubMed

We investigated whether functional brain networks are different in coloured-hearing synaesthetes compared with non-synaesthetes. Based on resting state electroencephalographic (EEG) activity, graph-theoretical analysis was applied to functional connectivity data obtained from different frequency bands (theta, alpha1, alpha2, and beta) of 12 coloured-hearing synaesthetes and 13 non-synaesthetes. The analysis of functional connectivity was based on estimated intra-cerebral sources of brain activation using standardized low-resolution electrical tomography. These intra-cerebral sources of brain activity were subjected to graph-theoretical analysis yielding measures representing small-world network characteristics (cluster coefficients and path length). In addition, brain regions with strong interconnections were identified (so-called hubs), and the interconnectedness of these hubs were quantified using degree as a measure of connectedness. Our analysis was guided by the two-stage model proposed by Hubbard and Ramachandran (2005). In this model, the parietal lobe is thought to play a pivotal role in binding together the synaesthetic perceptions (hyperbinding). In addition, we hypothesized that the auditory cortex and the fusiform gyrus would qualify as strong hubs in synaesthetes. Although synaesthetes and non-synaesthetes demonstrated a similar small-world network topology, the parietal lobe turned out to be a stronger hub in synaesthetes than in non-synaesthetes supporting the two-stage model. The auditory cortex was also identified as a strong hub in these coloured-hearing synaesthetes (for the alpha2 band). Thus, our a priori hypotheses receive strong support. Several additional hubs (for which no a priori hypothesis has been formulated) were found to be different in terms of the degree measure in synaesthetes, with synaesthetes demonstrating stronger degree measures indicating stronger interconnectedness. These hubs were found in brain areas known to be involved in controlling memory processes (alpha1: hippocampus and retrosplenial area), executive functions (alpha1 and alpha2: ventrolateral prefrontal cortex; theta: inferior frontal cortex), and the generation of perceptions (theta: extrastriate cortex; beta: subcentral area). Taken together this graph-theoretical analysis of the resting state EEG supports the two-stage model in demonstrating that the left-sided parietal lobe is a strong hub region, which is stronger functionally interconnected in synaesthetes than in non-synaesthetes. The right-sided auditory cortex is also a strong hub supporting the idea that coloured-hearing synaesthetes demonstrate a specific auditory cortex. A further important point is that these hub regions are even differently operating at rest supporting the idea that these hub characteristics are predetermining factors of coloured-hearing synaesthesia. PMID:21923785

Jäncke, Lutz; Langer, Nicolas

2011-09-01

374

EEG evidence for mirror neuron dysfunction in autism spectrum disorders  

Microsoft Academic Search

Autism spectrum disorders (ASD) are largely characterized by deficits in imitation, pragmatic language, theory of mind, and empathy. Previous research has suggested that a dysfunctional mirror neuron system may explain the pathology observed in ASD. Because EEG oscillations in the mu frequency (8–13 Hz) over sensorimotor cortex are thought to reflect mirror neuron activity, one method for testing the integrity

Lindsay M. Oberman; Edward M. Hubbard; Joseph P. McCleery; Eric L. Altschuler; Vilayanur S. Ramachandran; Jaime A. Pineda

2005-01-01

375

Epileptic networks studied with EEG-fMRI  

PubMed Central

SUMMARY It is not easy to determine the location of the cerebral generators and the other brain regions that may be involved at the time of an epileptic spike seen in the scalp EEG. The possibility to combine EEG recording with functional MRI scanning (fMRI) opens the opportunity to uncover the regions of the brain showing changes in metabolism and blood flow in response to epileptic spikes seen in the EEG. These regions are presumably involved in the abnormal neuronal activity at the origin of epileptic discharges. This paper reviews the methodology involved in performing such studies, including the special techniques required for recording the EEG inside the scanner and the statistical issues in analyzing the fMRI signal. We then discuss the results obtained in patients with different types of focal epileptic disorders and in patients with primary generalized epilepsy. The results in general indicate that interictal epileptic discharges may affect brain areas well beyond the presumed region in which they are generated. The noninvasive nature of this method opens new horizons in the investigation of brain regions involved and affected by epileptic discharges. PMID:18304255

Gotman, Jean

2013-01-01

376

Telemetric EEG and the Rat: A Guide For Neuroscientists  

PubMed Central

Telemetric EEG in the rat’s brain has been used for experiments which tests the effects of an antiepileptic compound on it’s antiseizures activity. A simple classification correlating epileptiform discharge and Racine’s behavioral activity is discussed. PMID:23613643

Abdullah, Jafri Malin; Rafiqul Islam, Mohammad

2012-01-01

377

Model-Based Spike Detection of Epileptic EEG Data  

PubMed Central

Accurate automatic spike detection is highly beneficial to clinical assessment of epileptic electroencephalogram (EEG) data. In this paper, a new two-stage approach is proposed for epileptic spike detection. First, the k-point nonlinear energy operator (k-NEO) is adopted to detect all possible spike candidates, then a newly proposed spike model with slow wave features is applied to these candidates for spike classification. Experimental results show that the proposed system, using the AdaBoost classifier, outperforms the conventional method in both two- and three-class EEG pattern classification problems. The proposed system not only achieves better accuracy for spike detection, but also provides new ability to differentiate between spikes and spikes with slow waves. Though spikes with slow waves occur frequently in epileptic EEGs, they are not used in conventional spike detection. Identifying spikes with slow waves allows the proposed system to have better capability for assisting clinical neurologists in routine EEG examinations and epileptic diagnosis. PMID:24048343

Liu, Yung-Chun; Lin, Chou-Ching K.; Tsai, Jing-Jane; Sun, Yung-Nien

2013-01-01

378

Active data selection for motor imagery EEG classification.  

PubMed

Rejecting or selecting data from multiple trials of electroencephalography (EEG) recordings is crucial. We propose a sparsity-aware method to data selection from a set of multiple EEG recordings during motor-imagery tasks, aiming at brain machine interfaces (BMIs). Instead of empirical averaging over sample covariance matrices for multiple trials including low-quality data, which can lead to poor performance in BMI classification, we introduce weighted averaging with weight coefficients that can reject such trials. The weight coefficients are determined by the l1-minimization problem that lead to sparse weights such that almost zero-values are allocated to low-quality trials. The proposed method was successfully applied for estimating covariance matrices for the so-called common spatial pattern (CSP) method, which is widely used for feature extraction from EEG in the two-class classification. Classification of EEG signals during motor imagery was examined to support the proposed method. It should be noted that the proposed data selection method can be applied to a number of variants of the original CSP method. PMID:25248173

Tomida, Naoki; Tanaka, Toshihisa; Ono, Shunsuke; Yamagishi, Masao; Higashi, Hiroshi

2015-02-01

379

EEG power, frequency, asymmetry and coherence in male depression  

Microsoft Academic Search

Quantitative electroencephalographic (EEG) power topography has served as a useful tool for investigating brain regional mechanisms underlying affective disorders. In an attempt to examine the role of gender and widen the scope of the measurement probes used in these investigations, the traditional power and inter-hemispheric power ratio indices were supplemented with intra-hemispheric power ratios, mean frequency and both inter and

Verner Knott; Colleen Mahoney; Sidney Kennedy; Kenneth Evans

2001-01-01

380

Development of wireless high immunity EEG recording system  

Microsoft Academic Search

In this study, a single channel wireless EEG acquisition system is developed for biomedical instrumentation. This system is divided into two parts: analog front end circuit and a digital processing circuit. The analog part includes a protection circuitry, preamplifier, filters, programmable gain amplifier and DRL circuit. Simulation results of this part have shown a low noise level of about 16nV

Hyem Saadi; Merzak Ferroukhi; Mokhtar Attari

2011-01-01

381

Review on solving the inverse problem in EEG source analysis  

Microsoft Academic Search

In this primer, we give a review of the inverse problem for EEG source localization. This is intended for the researchers new in the field to get insight in the state-of-the-art techniques used to find approximate solutions of the brain sources giving rise to a scalp potential recording. Furthermore, a review of the performance results of the different techniques is

Roberta Grech; Tracey Cassar; Joseph Muscat; Kenneth P Camilleri; Simon G Fabri; Michalis Zervakis; Petros Xanthopoulos; Vangelis Sakkalis; Bart Vanrumste

2008-01-01

382

A stochastic model for EEG microstate sequence analysis.  

PubMed

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. PMID:25451473

Gärtner, Matthias; Brodbeck, Verena; Laufs, Helmut; Schneider, Gaby

2015-01-01

383

Pattern Recognition of Human Grasping Operations Based on EEG  

Microsoft Academic Search

The pattern recognition of the complicated grasping operation based on electroencephalography (simply named as EEG) is very helpful on realtime control of the robotic hand. In the paper, a new spectral feature analysis method based on Band Pass Filter (simply named as BPF) and Power Spectral Analysis (simply named as PSA) is presented for discriminating the complicated grasping operations. By

Xiao Dong Zhang; Hyouk Ryeol Choi

2006-01-01

384

MEG and TMS combined with EEG for mapping alcohol effects  

Microsoft Academic Search

Magnetoencephalography (MEG) is a noninvasive method of studying magnetic fields from outside the skull that are generated by at least partially synchronized neuronal populations in the brain. The advantage of MEG over electroencephalography (EEG) is the transparency of the skull, scalp, and brain tissue to the magnetic fields, which facilitates easy localization of the cortical activity. In MEG, alcohol increased

Seppo Kähkönen

2005-01-01

385

EEG phase patterns reflect the selectivity of neural firing.  

PubMed

Oscillations are pervasive in encephalographic signals and supposedly reflect cognitive processes and sensory representations. While the relation between oscillation amplitude (power) and sensory-cognitive variables has been extensively studied, recent work reveals that the dynamic oscillation signature (phase pattern) can carry information about such processes to a greater degree than amplitude. To elucidate the neural correlates of oscillatory phase patterns, we compared the stimulus selectivity of neural firing rates and auditory-driven electroencephalogram (EEG) oscillations. We employed the same naturalistic sound stimuli in 2 experiments, one recording scalp EEGs in humans and one recording intracortical local field potentials (LFPs) and single neurons in macaque auditory cortex. Using stimulus decoding techniques, we show that stimulus selective firing patterns imprint on the phase rather than the amplitude of slow (theta band) oscillations in LFPs and EEG. In particular, we find that stimuli which can be discriminated by firing rates can also be discriminated by phase patterns but not by oscillation amplitude and that stimulus-specific phase patterns also persist in the absence of increases of oscillation power. These findings support a neural basis for stimulus selective and entrained EEG phase patterns and reveal a level of interrelation between encephalographic signals and neural firing beyond simple amplitude covariations in both signals. PMID:22345353

Ng, Benedict Shien Wei; Logothetis, Nikos K; Kayser, Christoph

2013-02-01

386

Hemimegalencephaly: Clinical, EEG, neuroimaging, and IMP-SPECT correlation  

SciTech Connect

Iofetamine-single photon emission computed tomography (IMP-SPECT) was performed on 2 girls (5 1/2 and 6 years of age) with histories of intractable seizures, developmental delay, and unilateral hemiparesis secondary to hemimegalencephaly. Electroencephalography (EEG) revealed frequent focal discharges in 1 patient, while a nearly continuous burst suppression pattern over the malformed hemisphere was recorded in the other. IMP-SPECT demonstrated a good correlation with neuroimaging studies. In spite of the different EEG patterns, which had been proposed to predict contrasting clinical outcomes, both IMP-SPECT scans disclosed a similar decrease in tracer uptake in the malformed hemisphere. These results are consistent with the pattern of decreased tracer uptake found in other interictal studies of focal seizures without cerebral malformations. In view of recent recommendations for hemispherectomy in these patients, we suggest that the IMP-SPECT scan be used to compliment EEG as a method to define the extent of abnormality which may be more relevant to long-term prognosis than EEG alone.

Konkol, R.J.; Maister, B.H.; Wells, R.G.; Sty, J.R. (Medical College of Wisconsin, Milwaukee (USA))

1990-11-01

387

EEG Correlates of Emotional Problems and Conduct Disorder in Schoolchildren  

Microsoft Academic Search

The relationships between EEG and the teachers' and parents' ratings of conduct disorder and emotional problems were studied in 20 schoolchildren between the ages of 9 to 13 years. For the assessment of behavioral and emotional problems, we used the Rutter questionnaire for teachers and the Achenbach questionnaire for parents. The intelligence was determined with the Wechsler test. The electroencephalogram

G. G. Knyazev; H. R. Slobodskaya; L. I. Aftanas; N. N. Savina

2002-01-01

388

Health Instruction Packages: Medical Technologies--EEG, Radiology, & Biomedical Photography.  

ERIC Educational Resources Information Center

Text, illustrations, and exercises are utilized in this set of four learning modules to instruct medical technology students in a variety of job-related skills. The first module, "EEG Technology: Measurement Technique of the 'International 10-20 System'" by Dorothea Brittenham, describes a procedure used by electroencephalograph technicians to…

Brittenham, Dorothea; And Others

389

Alphai-Antitrypsin Serum Concentration and Phenotypes in Ulcerative Colitis  

Microsoft Academic Search

96 unrelated patients suffering from ulcerative colitis were typed for the electrophoretic variants of alpha1-antitrypsin (?1-AT). None of the phenotypes showed a definite association with this condition. The serum concentration of ?1-AT was increased compared with healthy control subjects. There was a positive correlation between the serum concentration of ?1-AT and activity of the ulcerative colitis.Copyright © 1984 S. Karger

I. Biemond; W. S. Selby; D. P. Jewell; E. C. Klasen

1984-01-01

390

Preoperational radiation surveillance of the WIPP project by EEG during 1992  

SciTech Connect

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/{mu}g 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.

Kenney, J.W.

1994-02-01

391

An ontology for microbial phenotypes.  

PubMed

BackgroundPhenotypic data are routinely used to elucidate gene function in organisms amenable to genetic manipulation. However, previous to this work, there was no generalizable system in place for the structured storage and retrieval of phenotypic information for bacteria.ResultsThe Ontology of Microbial Phenotypes (OMP) has been created to standardize the capture of such phenotypic information from microbes. OMP has been built on the foundations of the Basic Formal Ontology and the Phenotype and Trait Ontology. Terms have logical definitions that can facilitate computational searching of phenotypes and their associated genes. OMP can be accessed via a wiki page as well as downloaded from SourceForge. Initial annotations with OMP are being made for Escherichia coli using a wiki-based annotation capture system. New OMP terms are being concurrently developed as annotation proceeds.ConclusionsWe anticipate that diverse groups studying microbial genetics and associated phenotypes will employ OMP for standardizing microbial phenotype annotation, much as the Gene Ontology has standardized gene product annotation. The resulting OMP resource and associated annotations will facilitate prediction of phenotypes for unknown genes and result in new experimental characterization of phenotypes and functions. PMID:25433798

Chibucos, Marcus C; Zweifel, Adrienne E; Herrera, Jonathan C; Meza, William; Eslamfam, Shabnam; Uetz, Peter; Siegele, Deborah A; Hu, James C; Giglio, Michelle G

2014-11-30

392

Alpha Band Cortico-Muscular Coherence Occurs in Healthy Individuals during Mechanically-Induced Tremor  

PubMed Central

The present work aimed at investigating the effects of mechanically amplified tremor on cortico-muscular coherence (CMC) in the alpha band. The study of CMC in this specific band is of particular interest because this coherence is usually absent in healthy individuals and it is an aberrant feature in patients affected by pathological tremors; understanding its mechanisms is therefore important. Thirteen healthy volunteers (23±4 years) performed elbow flexor sustained contractions both against a spring load and in isometric conditions at 20% of maximal voluntary isometric contraction (MVC). Spring stiffness was selected to induce instability in the stretch reflex servo loop. 64 EEG channels, surface EMG from the biceps brachii muscle and force were simultaneously recorded. Contractions against the spring resulted in greater fluctuations of the force signal and EMG amplitude compared to isometric conditions (p<.05). During isometric contractions CMC was systematically found in the beta band and sporadically observed in the alpha band. However, during the contractions against the spring load, CMC in the alpha band was observed in 12 out of 13 volunteers. Partial directed coherence (PDC) revealed an increased information flow in the EMG to EEG direction in the alpha band (p<.05). Therefore, coherence in the alpha band between the sensory-motor cortex and the biceps brachii muscle can be systematically induced in healthy individuals by mechanically amplifying tremor. The increased information flow in the EMG to EEG direction may reflect enhanced afferent activity from the muscle spindles. These results may contribute to the understanding of the presence of alpha band CMC in tremor related pathologies by suggesting that the origin of this phenomenon may not only be at cortical level but may also be affected by spinal circuit loops. PMID:25514444

Budini, Francesco; McManus, Lara M.; Berchicci, Marika; Menotti, Federica; Macaluso, Andrea; Di Russo, Francesco; Lowery, Madeleine M.; De Vito, Giuseppe

2014-01-01

393

Propofol Anesthesia and Sleep: A High-Density EEG Study  

PubMed Central

Study Objectives: The electrophysiological correlates of anesthetic sedation remain poorly understood. We used high-density electroencephalography (hd-EEG) and source modeling to investigate the cortical processes underlying propofol anesthesia and compare them to sleep. Design: 256-channel EEG recordings in humans during propofol anesthesia. Setting: Hospital operating room. Patients or Participants: 8 healthy subjects (4 males) Interventions: N/A Measurements and Results: Initially, propofol induced increases in EEG power from 12–25 Hz. Loss of consciousness (LOC) was accompanied by the appearance of EEG slow waves that resembled the slow waves of NREM sleep. We compared slow waves in propofol to slow waves recorded during natural sleep and found that both populations of waves share similar cortical origins and preferentially propagate along the mesial components of the default network. However, propofol slow waves were spatially blurred compared to sleep slow waves and failed to effectively entrain spindle activity. Propofol also caused an increase in gamma (25–40 Hz) power that persisted throughout LOC. Source modeling analysis showed that this increase in gamma power originated from the anterior and posterior cingulate cortices. During LOC, we found increased gamma functional connectivity between these regions compared to the wakefulness. Conclusions: Propofol anesthesia is a sleep-like state and slow waves are associated with diminished consciousness even in the presence of high gamma activity. Citation: Murphy M; Bruno MA; Riedner BA; Boveroux P; Noirhomme Q; Landsness EC; Brichant JF; Phillips C; Massimini M; Laureys S; Tononi G; Boly M. Propofol anesthesia and sleep: a high-density EEG study. SLEEP 2011;34(3):283-291. PMID:21358845

Murphy, Michael; Bruno, Marie-Aurelie; Riedner, Brady A.; Boveroux, Pierre; Noirhomme, Quentin; Landsness, Eric C.; Brichant, Jean-Francois; Phillips, Christophe; Massimini, Marcello; Laureys, Steven; Tononi, Giulio; Boly, Melanie

2011-01-01

394

Reversing pathologically increased EEG power by acoustic coordinated reset neuromodulation  

PubMed Central

Acoustic Coordinated Reset (CR) neuromodulation is a patterned stimulation with tones adjusted to the patient's dominant tinnitus frequency, which aims at desynchronizing pathological neuronal synchronization. In a recent proof-of-concept study, CR therapy, delivered 4–6 h/day more than 12 weeks, induced a significant clinical improvement along with a significant long-lasting decrease of pathological oscillatory power in the low frequency as well as ? band and an increase of the ? power in a network of tinnitus-related brain areas. As yet, it remains unclear whether CR shifts the brain activity toward physiological levels or whether it induces clinically beneficial, but nonetheless abnormal electroencephalographic (EEG) patterns, for example excessively decreased ? and/or ?. Here, we compared the patients' spontaneous EEG data at baseline as well as after 12 weeks of CR therapy with the spontaneous EEG of healthy controls by means of Brain Electrical Source Analysis source montage and standardized low-resolution brain electromagnetic tomography techniques. The relationship between changes in EEG power and clinical scores was investigated using a partial least squares approach. In this way, we show that acoustic CR neuromodulation leads to a normalization of the oscillatory power in the tinnitus-related network of brain areas, most prominently in temporal regions. A positive association was found between the changes in tinnitus severity and the normalization of ? and ? power in the temporal, parietal, and cingulate cortical regions. Our findings demonstrate a widespread CR-induced normalization of EEG power, significantly associated with a reduction of tinnitus severity. PMID:23907785

Adamchic, Ilya; Toth, Timea; Hauptmann, Christian; Tass, Peter Alexander

2014-01-01

395

Correntropy measures to detect daytime sleepiness from EEG signals.  

PubMed

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: ?, 0.1-4?Hz; ?, 4-8?Hz; ?, 8-12?Hz; ?, 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 ? 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). PMID:25237837

Melia, Umberto; Guaita, Marc; Vallverdú, Montserrat; Montserrat, Josep M; Vilaseca, Isabel; Salamero, Manel; Gaig, Carles; Caminal, Pere; Santamaria, Joan

2014-10-01

396

Reversing pathologically increased EEG power by acoustic coordinated reset neuromodulation.  

PubMed

Acoustic Coordinated Reset (CR) neuromodulation is a patterned stimulation with tones adjusted to the patient's dominant tinnitus frequency, which aims at desynchronizing pathological neuronal synchronization. In a recent proof-of-concept study, CR therapy, delivered 4-6 h/day more than 12 weeks, induced a significant clinical improvement along with a significant long-lasting decrease of pathological oscillatory power in the low frequency as well as ? band and an increase of the ? power in a network of tinnitus-related brain areas. As yet, it remains unclear whether CR shifts the brain activity toward physiological levels or whether it induces clinically beneficial, but nonetheless abnormal electroencephalographic (EEG) patterns, for example excessively decreased ? and/or ?. Here, we compared the patients' spontaneous EEG data at baseline as well as after 12 weeks of CR therapy with the spontaneous EEG of healthy controls by means of Brain Electrical Source Analysis source montage and standardized low-resolution brain electromagnetic tomography techniques. The relationship between changes in EEG power and clinical scores was investigated using a partial least squares approach. In this way, we show that acoustic CR neuromodulation leads to a normalization of the oscillatory power in the tinnitus-related network of brain areas, most prominently in temporal regions. A positive association was found between the changes in tinnitus severity and the normalization of ? and ? power in the temporal, parietal, and cingulate cortical regions. Our findings demonstrate a widespread CR-induced normalization of EEG power, significantly associated with a reduction of tinnitus severity. PMID:23907785

Adamchic, Ilya; Toth, Timea; Hauptmann, Christian; Tass, Peter Alexander

2014-05-01

397

Multi-class EEG classification of voluntary hand movement directions  

NASA Astrophysics Data System (ADS)

Objective. Studies have shown that low frequency components of brain recordings provide information on voluntary hand movement directions. However, non-invasive techniques face more challenges compared to invasive techniques. Approach. This study presents a novel signal processing technique to extract features from non-invasive electroencephalography (EEG) recordings for classifying voluntary hand movement directions. The proposed technique comprises the regularized wavelet-common spatial pattern algorithm to extract the features, mutual information-based feature selection, and multi-class classification using the Fisher linear discriminant. EEG data from seven healthy human subjects were collected while they performed voluntary right hand center-out movement in four orthogonal directions. In this study, the movement direction dependent signal-to-noise ratio is used as a parameter to denote the effectiveness of each temporal frequency bin in the classification of movement directions. Main results. Significant (p < 0.005) movement direction dependent modulation in the EEG data was identified largely towards the end of movement at low frequencies (?6 Hz) from the midline parietal and contralateral motor areas. Experimental results on single trial classification of the EEG data collected yielded an average accuracy of (80.24 ± 9.41)% in discriminating the four different directions using the proposed technique on features extracted from low frequency components. Significance. The proposed feature extraction strategy provides very high multi-class classification accuracies, and the results are proven to be more statistically significant than existing methods. The results obtained suggest the possibility of multi-directional movement classification from single-trial EEG recordings using the proposed technique in low frequency components.

Robinson, Neethu; Guan, Cuntai; Vinod, A. P.; Keng Ang, Kai; Tee, Keng Peng

2013-10-01

398

EEG Theta and Alpha Responses Reveal Qualitative Differences in Processing Taxonomic versus Thematic Semantic Relationships  

ERIC Educational Resources Information Center

Despite the importance of semantic relationships to our understanding of semantic knowledge, the nature of the neural processes underlying these abilities are not well understood. In order to investigate these processes, 20 healthy adults listened to thematically related (e.g., leash-dog), taxonomically related (e.g., horse-dog), or unrelated…

Maguire, Mandy J.; Brier, Matthew R.; Ferree, Thomas C.

2010-01-01

399

A Brain-Machine Interface Based on EEG: Extracted Alpha Waves Applied to Mobile Robot  

Microsoft Academic Search

The increasing number of signal processing tools for highly parallel neurophysiological recordings opens up new avenues for connecting technologies directly to neuronal processes. As the understanding is taking a better shape, lot more work to perform is coming up. A simple brain-machine interface may be able to reestablish the broken loop of the persons with motor dysfunction. With time the

Mufti Mahmud; David Hawellek; Aleksander Valjamae

2009-01-01

400

Resting EEG in Alpha and Beta Bands Predicts Individual Differences in Attentional Blink Magnitude  

ERIC Educational Resources Information Center

Accuracy for a second target (T2) is reduced when it is presented within 500 ms of a first target (T1) in a rapid serial visual presentation (RSVP)--an attentional blink (AB). There are reliable individual differences in the magnitude of the AB. Recent evidence has shown that the attentional approach that an individual typically adopts during a…

MacLean, Mary H.; Arnell, Karen M.; Cote, Kimberly A.

2012-01-01

401

A stable pattern of EEG spectral coherence distinguishes children with autism from neuro-typical controls - a large case control study  

PubMed Central

Background The autism rate has recently increased to 1 in 100 children. Genetic studies demonstrate poorly understood complexity. Environmental factors apparently also play a role. Magnetic resonance imaging (MRI) studies demonstrate increased brain sizes and altered connectivity. Electroencephalogram (EEG) coherence studies confirm connectivity changes. However, genetic-, MRI- and/or EEG-based diagnostic tests are not yet available. The varied study results likely reflect methodological and population differences, small samples and, for EEG, lack of attention to group-specific artifact. Methods Of the 1,304 subjects who participated in this study, with ages ranging from 1 to 18 years old and assessed with comparable EEG studies, 463 children were diagnosed with autism spectrum disorder (ASD); 571 children were neuro-typical controls (C). After artifact management, principal components analysis (PCA) identified EEG spectral coherence factors with corresponding loading patterns. The 2- to 12-year-old subsample consisted of 430 ASD- and 554 C-group subjects (n = 984). Discriminant function analysis (DFA) determined the spectral coherence factors' discrimination success for the two groups. Loading patterns on the DFA-selected coherence factors described ASD-specific coherence differences when compared to controls. Results Total sample PCA of coherence data identified 40 factors which explained 50.8% of the total population variance. For the 2- to 12-year-olds, the 40 factors showed highly significant group differences (P < 0.0001). Ten randomly generated split half replications demonstrated high-average classification success (C, 88.5%; ASD, 86.0%). Still higher success was obtained in the more restricted age sub-samples using the jackknifing technique: 2- to 4-year-olds (C, 90.6%; ASD, 98.1%); 4- to 6-year-olds (C, 90.9%; ASD 99.1%); and 6- to 12-year-olds (C, 98.7%; ASD, 93.9%). Coherence loadings demonstrated reduced short-distance and reduced, as well as increased, long-distance coherences for the ASD-groups, when compared to the controls. Average spectral loading per factor was wide (10.1 Hz). Conclusions Classification success suggests a stable coherence loading pattern that differentiates ASD- from C-group subjects. This might constitute an EEG coherence-based phenotype of childhood autism. The predominantly reduced short-distance coherences may indicate poor local network function. The increased long-distance coherences may represent compensatory processes or reduced neural pruning. The wide average spectral range of factor loadings may suggest over-damped neural networks. PMID:22730909

2012-01-01

402

Variations in resting frontal alpha asymmetry between high- and low-neuroticism females across the menstrual cycle.  

PubMed

Resting frontal alpha asymmetry measures the relative activation intensity across the left and right frontal regions that represent emotional experience. Here, the focus is on levels of alpha asymmetry between high- and low-neuroticism females across the menstrual cycle. Resting alpha asymmetry in healthy females who scored high or low on neuroticism was assessed during the menstrual phase, the late follicular phase, and the midlate luteal phase. High-neuroticism females exhibited lower relative left prefrontal activity than did low-neuroticism females during the midlate luteal phase, as indexed by alpha1 and alphaTotal asymmetry scores at the prefrontal electrode positions (FP1/2 ). EEG results demonstrate that the resting frontal alpha asymmetry of high- and low-neuroticism females was moderated by the menstrual cycle, and high-neuroticism females should pay particular attention to their emotional experience during the midlate luteal phase. PMID:25154679

Huang, Yamei; Zhou, Renlai; Cui, Hong; Wu, Mengying; Wang, Qingguo; Zhao, Yan; Liu, Yanfeng

2015-02-01

403

Genotypic-Phenotypic Correlative Studies  

Cancer.gov

The CBRG is a co-sponsor of the Cooperative Family Registry for Colon Cancer, established to support genotypic-phenotpic-correlative studies. The necessity for elucidating the relationship between genotype and phenotype is becoming particularly important when detection methods uncover changes in the genomic DNA without knowing if the changes are causing changes in the phenotype or if the phenotype has an association with clinical outcome.

404

PGC-1alpha deficiency causes multi-system energy metabolic derangements: muscle dysfunction, abnormal weight control and hepatic steatosis.  

PubMed

The gene encoding the transcriptional coactivator peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) was targeted in mice. PGC-1alpha null (PGC-1alpha(-/-)) mice were viable. However, extensive phenotyping revealed multi-system abnormalities indicative of an abnormal energy metabolic phenotype. The postnatal growth of heart and sl