Note: This page contains sample records for the topic eeg alpha phenotypes from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

PSYCHOPHYSICS OF EEG ALPHA STATE DISCRIMINATION  

PubMed Central

Nearly all research in neurofeedback since the 1960s has focused on training voluntary control over EEG constructs. By contrast, EEG state discrimination training focuses on awareness of subjective correlates of EEG states. This study presents the first successful replication of EEG alpha state discrimination first reported by Kamiya (1962). A 150-second baseline was recorded in 106 participants. During the task, low (<30th percentile of the baseline) and high alpha events (>70th percentile) triggered a prompt. Participants indicated “high” or “low” with a keypress response and received immediate feedback. Seventy-five percent of participants achieved significant discrimination within nine sessions, with a significant learning curve effect. Performance was significantly related to physical properties of the EEG signal, including magnitude, duration, and absolute vs. relative amplitude. These results are consistent with a conceptualization of EEG state discrimination as a sensory modality, although it is also intricately related to voluntary control of these states.

Frederick, Jon A.

2012-01-01

2

HTR3B is associated with alcoholism with antisocial behavior and alpha EEG power--an intermediate phenotype for alcoholism and co-morbid behaviors  

PubMed Central

Alcohol use disorders (AUD) with co-morbid antisocial personality disorder (ASPD) have been associated with serotonin (5-HT) dysfunction. 5-HT3 receptors are potentiated by ethanol and appear to modulate reward. 5-HT3 receptor antagonists may be useful in the treatment of early-onset alcoholics with co-morbid ASPD. Low-voltage alpha electroencephalogram (EEG) power, a highly heritable trait, has been associated with both AUD and ASPD. A recent whole genome linkage scan in one of our samples, Plains American Indians (PI), has shown a suggestive linkage peak for alpha power at the 5-HT3R locus. We tested whether genetic variation within the HTR3A and HTR3B genes influences vulnerability to AUD with comorbid ASPD (AUD + ASPD) and moderates alpha power. Our study included three samples: 284 criminal alcoholic Finnish Caucasians and 234 controls; two independent community-ascertained samples with resting EEG recordings: a predominantly Caucasian sample of 191 individuals (Bethesda) and 306 PI. In the Finns, an intronic HTR3B SNP rs3782025 was associated with AUD + ASPD (P = .004). In the Bethesda sample, the same allele predicted lower alpha power (P = 7.37e-5). Associations between alpha power and two other HTR3B SNPs were also observed among PI (P = .03). One haplotype in the haplotype block at the 3? region of the gene that included rs3782025 was associated with AUD + ASPD in the Finns (P = .02) and with reduced alpha power in the Bethesda population (P = .00009). Another haplotype in this block was associated with alpha power among PI (P = .03). No associations were found for HTR3A. Genetic variation within HTR3B may influence vulnerability to develop AUD with comorbid ASPD. 5-HT3R might contribute to the imbalance between excitation and inhibition that characterize the brain of alcoholics.

Ducci, Francesca; Enoch, Mary-Anne; Yuan, Qiaoping; Shen, Pei-Hong; White, Kenneth V.; Hodgkinson, Colin; Albaugh, Bernard; Virkkunen, Matti; Goldman, David

2009-01-01

3

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.

Fink, Andreas; Benedek, Mathias

2014-01-01

4

Eeg alpha, skin conductance and hypnotizability in antarctica  

Microsoft Academic Search

On the basis of alternative hypotheses in the literature, 9 invited Ss undergoing wintering-over isolation at Scott Base, Antarctica, were tested for EEG alpha and hypnotizability. 8-channels of EEG, bipolar skin conductance (SC) and hypnotizability data were collected at Scott Base prior to and following the wintering-over isolation. Significant increases in alpha density and hypnotizability were found in Ss following

Arreed F. Barabasz

1980-01-01

5

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

6

Clinical and EEG phenotypes of epilepsy in the baboon ( Papio hamadryas spp.)  

Microsoft Academic Search

Spontaneous seizures have been reported in several baboon subspecies housed at the Southwest Foundation for Biomedical Research (SFBR), including Papio hamadryas anubis as well as cynocephalus\\/anubis and other hybrids. This study classified clinical and electroencephalographic (EEG) phenotypes in these subspecies based upon interictal and ictal findings, as well as photosensitivity, by scalp EEG. One hundred baboons underwent 1-h EEG studies

C. Ákos Szabó; M. Michelle Leland; Koyle Knape; James J. Elliott; Vicky Haines; Jeff T. Williams

2005-01-01

7

Alpha 1 antitrypsin phenotypes and alcoholic pancreatitis.  

PubMed Central

Altered frequencies of alpha 1 antitrypsin phenotypes have been reported in patients with chronic pancreatitis, suggesting a possible genetic basis for individual susceptibility to this disease. Alpha 1 antitrypsin phenotypes, with particular regard to alcoholic pancreatitis, were studied. Patients with alcoholic pancreatitis were compared with alcoholic control subjects with no history of pancreatic disease. Serum alpha 1 antitrypsin concentrations were raised in pancreatitis patients sampled within one month of an acute attack of pancreatitis, but otherwise values were similar to those of control subjects. There were no significant differences in alpha 1 antitrypsin phenotypes between alcoholics with pancreatitis and alcoholic control subjects. This study of alpha 1 antitrypsin phenotypes provides no evidence of an inherited susceptibility to alcoholic pancreatitis.

Haber, P S; Wilson, J S; McGarity, B H; Hall, W; Thomas, M C; Pirola, R C

1991-01-01

8

Finding thalamic BOLD correlates to posterior alpha EEG.  

PubMed

Oscillatory electrical brain activity in the alpha (8-13 Hz) band is a prominent feature of human electroencephalography (EEG) during alert wakefulness, and is commonly thought to arise primarily from the occipital and parietal parts of the cortex. While the thalamus is considered to play a supportive role in the generation and modulation of cortical alpha rhythms, its precise function remains controversial and incompletely understood. To address this, we evaluated the correlation between the blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) signals in the thalamus and the spontaneous modulation of posterior alpha rhythms based on EEG-fMRI data acquired concurrently during an eyes-closed task-free condition. We observed both negative and positive correlations in the thalamus. The negative correlations were mostly seen within the visual thalamus, with a preference for the pulvinar over lateral geniculate nuclei. The positive correlations were found at the anterior and medial dorsal nuclei. Through functional connectivity analysis of the fMRI data, the pulvinar was found to be functionally associated with the same widespread cortical visual areas where the fMRI signals were negatively correlated with the posterior alpha modulation. In contrast, the dorsal nuclei were part of a distinct functional network that included brain stem, cingulate cortex and cerebellum. These observations are consistent with previous animal electrophysiology studies and the notion that the visual thalamus, and the pulvinar in particular, is intimately involved in the generation and spontaneous modulation of posterior alpha rhythms, facilitated by its reciprocal and widespread interaction with the cortical visual areas. We further postulate that the anterior and medial dorsal nuclei, being part of the ascending neuromodulatory system, may indirectly modulate cortical alpha rhythms by affecting vigilance and arousal levels. PMID:22986355

Liu, Zhongming; de Zwart, Jacco A; Yao, Bing; van Gelderen, Peter; Kuo, Li-Wei; Duyn, Jeff H

2012-11-15

9

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

10

EEG spectral phenotypes: heritability and association with marijuana and alcohol dependence in an American Indian community study  

PubMed Central

Native Americans have some of the highest rates of marijuana and alcohol use and abuse, yet neurobiological measures associated with dependence on these substances in this population remain unknown. The present investigation evaluated the heritability of spectral characteristics of the electroencephalogram (EEG) and their correlation with marijuana and alcohol dependence in an American Indian community. Participants (n=626) were evaluated for marijuana (MJ) and alcohol (ALC) dependence, as well as other psychiatric disorders. EEGs were collected from six cortical sites and spectral power determined in five frequency bands (delta 1.0–4.0 Hz, theta 4.0–7.5 Hz, alpha 7.5–12.0 Hz, low beta 12.0–20.0 Hz and high beta/gamma 20–50 Hz). The estimated heritability (h2) of the EEG phenotypes was calculated using SOLAR, and ranged from 0.16 to 0.67. Stepwise linear regression was used to detect correlations between MJ and ALC dependence and the spectral characteristics of the EEG using a model that took into account: age, gender, Native American Heritage (NAH) and a lifetime diagnosis of antisocial personality and/or conduct disorder (ASPD/CD). Increases in spectral power in the delta frequency range, were significantly correlated with gender (p<0.001) and marijuana dependence (p<0.003). Gender, age, NAH and ASPD/CD were all significantly (p<0.001) correlated with theta, alpha and beta band power, whereas alcohol dependence (p<0.01), gender (p<0.001), and ASPD/CD (p<0.001) were all correlated with high beta/gamma band power. These data suggest that the traits of EEG delta and high beta /gamma activity are correlated with MJ dependence and alcohol dependence, respectively, in this community sample of Native Americans.

Ehlers, Cindy L.; Phillips, Evelyn; Gizer, Ian R.; Gilder, David A.; Wilhelmsen, Kirk C.

2009-01-01

11

Common and specific genetic influences on EEG power bands delta, theta, alpha, and beta.  

PubMed

It is difficult to study the genetic basis of psychological function/dysfunction due to its etiological complexity. Instead, we studied a biological marker, EEG power, which is associated with various psychological phenotypes and is closer to gene function. Previous studies have consistently demonstrated high heritability of EEG band power, but less is known about how common or specific genes influence each power band. For 519 adolescent twin pairs, spectral powers were calculated for delta, theta, alpha, and beta bands at bilateral occipital and frontal sites. All four bands were entered into a multivariate genetic model, with occipital and frontal sites modelled separately. Variance was decomposed into additive (A) and dominant (D) genetic factors, and common (C) and unique (E) environmental factors. Band heritabilities were higher at occipital (0.75-0.86) than frontal sites (0.46-0.80). Both common and specific genetic factors influenced the bands, with common genetic and specific genetic factors having more influence in the occipital and frontal regions, respectively. Non-additive genetic effects on beta power and a common environment effect on delta, theta, and alpha powers were observed in the frontal region. PMID:17316957

Zietsch, Brendan P; Hansen, Jonathan L; Hansell, Narelle K; Geffen, Gina M; Martin, Nicholas G; Wright, Margaret J

2007-05-01

12

[Alpha band coherence analysis of EEG in healthy adult's and Alzheimer's type dementia patients].  

PubMed

We studied the occipital inter-hemispheric coherence (IHCoh) of EEG (electrodes O1-O2) for alpha band (alpha1 - 8,0 to 10,0 Hz and alpha2 - 10,1 to 12,5 Hz) in healthy adults and Alzheimer's type dementia (ATD) subjects, to observe if there is any significant difference between these two groups that could help in the early diagnosis of ATD. We found a decrease of occipital IHCoh in ATD group for both alpha sub-bands. We believe that Coh analysis of EEG is a powerful auxiliary method in ATD diagnosis. PMID:10849626

Anghinah, R; Kanda, P A; Jorge, M S; Lima, E E; Pascuzzi, L; Melo, A C

2000-06-01

13

Task-related modulation of anterior theta and posterior alpha EEG reflects top-down preparation  

PubMed Central

Background Prestimulus EEG alpha activity in humans has been considered to reflect ongoing top-down preparation for the performance of subsequent tasks. Since theta oscillations may be related to poststimulus top-down processing, we investigated whether prestimulus EEG theta activity also reflects top-down cognitive preparation for a stimulus. Results We recorded EEG data from 15 healthy controls performing a color and shape discrimination task, and used the wavelet transformation to investigate the time course and power of oscillatory activity in the signals. We observed a relationship between both anterior theta and posterior alpha power in the prestimulus period and the type of subsequent task. Conclusions Since task-differences were reflected in both theta and alpha activities prior to stimulus onset, both prestimulus theta (particularly around the anterior region) and prestimulus alpha (particularly around the posterior region) activities may reflect prestimulus top-down preparation for the performance of subsequent tasks.

2010-01-01

14

EEG alpha distinguishes between cuneal and precuneal activation in working memory  

Microsoft Academic Search

In the literature on EEG during working memory (WM), the role of alpha power (8–13 Hz) during WM retention has remained unclear.We recorded EEG while 18 subjects retained sets of consonants in memory for 3 s; setsize (ss4, ss6, ss8) determines memory workload.Theta power (4–8 Hz) increased with workload in all subjects in middle frontal electrodes. Using ICA, the increase in theta could

Lars Michels; Morteza Moazami-Goudarzi; Daniel Jeanmonod; Johannes Sarnthein

2008-01-01

15

Music perception and imagery in EEG: alpha band effects of task and stimulus.  

PubMed

Previous work has shown that mental imagination of sound generally elicits an increase of alpha band activity (8-12 Hz) in the electroencephalogram (EEG). In addition, alpha activity has been shown to be related to aspects of music processing. In the current study, EEG signatures were investigated for perception and imagery of two different natural musical phrases. The responses are compared between tasks and between stimuli. For all tasks and stimuli, posterior alpha band activity was seen, but differences are shown in the power of this response. As expected, imagery resulted in a significantly stronger alpha activation than perception. The comparison of the averaged responses to the stimuli also showed a difference in alpha power, although this effect is seen in different directions. These results are interpreted to indicate that both the tasks and the stimuli modulate an attentional network, which may relate to the inhibition of non-task relevant cortical areas, as well as engagement with the music. PMID:21945480

Schaefer, Rebecca S; Vlek, Rutger J; Desain, Peter

2011-12-01

16

EEG Alpha Asymmetry in Schizophrenia, Depression, PTSD, Panic Disorder, ADHD and Conduct Disorder  

Microsoft Academic Search

Models of laterality infer distinct aspects of EEG alpha asymmetry in clinical disorders, which has been replicated for over three decades. This biomarker now requires a more fine-grained assessment of its clinical utility as a diagnostic and treatment predictive marker. Here, within the same study we assessed resting brain laterality across six clinical disorders, for which deviant laterality has been

Evian Gordon; Donna M. Palmer; Nicholas Cooper

2010-01-01

17

Restricted environmental stimulation and the enhancement of hypnotizability: Pain, EEG alpha, skin conductance and temperature responses  

Microsoft Academic Search

Restricted environmental stimulation procedures were used with 10 Ss. The Stanford Hypnotic Clinical Scale: Adult (SHCS) of Morgan and J. R. Hilgard (1975), modified to include a posthypnotic suggestion for an analgesic reaction, and pain threshold and tolerance tests were administered prior to restricted environmental stimulation technique (REST), immediately after REST, and 10–14 days later. Occipital EEG alpha, skin conductance,

Arreed F. Barabasz

1982-01-01

18

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.

19

[EEG alpha band coherence analysis in healthy adults: preliminary results].  

PubMed

We studied the occipital inter-hemispheric coherence of Electroencephalogram (electrodes O1-O2) for alpha band (alpha1--8.0 to 10.0 Hz and alpha2--10.1 to 12.5 Hz) in two groups of healthy individuals (young adults and subjects older than 50 years-old), to assess if there is significant difference between this two age groups. No significant difference in alpha band coherences was found between these two age groups. PMID:15830070

Anghinah, Renato; Caramelli, Paulo; Takahashi, Daniel Yassumasa; Nitrini, Ricardo; Sameshima, Koichi

2005-03-01

20

Changes in EEG mean frequency and spectral purity during spontaneous alpha blocking.  

PubMed

Spontaneously occurring brief periods of lower voltage irregular activity occurring amid a background of alpha activity (i.e., alpha blocking) in eyes-closed resting occipital EEG recordings from 32 healthy human subjects have been investigated to determine the extent of changes of mean frequency and of spectral purity (degree of regularity/irregularity of the EEG activity) during such periods. New methods for determining mean frequency and spectral purity (the latter as a new measure, the Spectral Purity Index, which has a maximum value of 1.0 for a pure sine wave) permit their conjoint evaluation over a 0.5 sec window that is advanced along the EEG in 0.1 sec steps, thus permitting almost continuous feature extraction. The findings indicate that, although spectral purity invariably decreased during the periods of lower voltage irregular activity, the mean frequency remained relatively unaltered, i.e., it remained unchanged or it increased or decreased slightly but at most by 2.5 Hz. These results suggest that, at least for the periods of lower voltage irregular activity occurring spontaneously amid an alpha background during eyes-closed occipital EEG recordings, it may be inaccurate (as some authors have already suggested) to use the term 'low-voltage fast (or beta) activity.' PMID:1697252

Goncharova, I I; Barlow, J S

1990-09-01

21

Accordance between EEG alpha power and dual task performance for different visual cognitive tasks.  

PubMed

Evidence from clinical and experimental studies suggests that the left hemisphere is preferentially engaged in language processing and mathematical-analytic tasks while the right is involved with spatial relations and synthetic tasks. The purpose of the present study was to investigate accordance between dual task paradigm (effects of concurrent cognitive tasks on right- and left-hand finger tapping frequency) and EEG alpha power changes, which are used to conduct research in lateralization of cognitive function. Subjects performed reading, face recognition and line orientation tasks. First, the EEG was recorded during the tasks and, after six months, the dual task was carried out using the same cognitive tasks. Statistical analysis yielded no significant main effect for the hemispheres, performing hand and three cognitive tasks separately for the dual task and the EEG alpha power changes. However, significant correlation between the two methods was found, indicating the left parietal activation for the reading task, the right temporal activation for the line orientation task, and both hemispheric activation for the face recognition task. Results first suggest a significant accordance between dual task performance and EEG alpha asymmetry studies. PMID:11699330

Kalaycio?lu, C; Nalçaci, E

2001-08-01

22

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.

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

2014-01-01

23

Brain oscillations and human memory: EEG correlates in the upper alpha and theta band.  

PubMed

The EEG was recorded while subjects judged whether sequentially presented feature-concept pairs are semantically congruent. Later and without prior warning they had to perform a semantic and episodic memory task. The results show that the upper alpha band is most sensitive to the encoding and processing of semantic information. It is only the upper alpha band that distinguishes between good and bad semantic memory performers and that shows significant correlations with semantic memory performance during that time period, semantic processing actually takes place. Even when the influence of episodic memory was removed by partial correlations, a reliable association between upper alpha desynchronization and semantic memory was observed. PMID:9464642

Klimesch, W; Doppelmayr, M; Pachinger, T; Ripper, B

1997-11-28

24

Spontaneous Slow Fluctuation of EEG Alpha Rhythm Reflects Activity in Deep-Brain Structures: A Simultaneous EEG-fMRI Study  

PubMed Central

The emergence of the occipital alpha rhythm on brain electroencephalogram (EEG) is associated with brain activity in the cerebral neocortex and deep brain structures. To further understand the mechanisms of alpha rhythm power fluctuation, we performed simultaneous EEGs and functional magnetic resonance imaging recordings in human subjects during a resting state and explored the dynamic relationship between alpha power fluctuation and blood oxygenation level-dependent (BOLD) signals of the brain. Based on the frequency characteristics of the alpha power time series (APTS) during 20-minute EEG recordings, we divided the APTS into two components: fast fluctuation (0.04–0.167 Hz) and slow fluctuation (0–0.04 Hz). Analysis of the correlation between the MRI signal and each component revealed that the slow fluctuation component of alpha power was positively correlated with BOLD signal changes in the brain stem and the medial part of the thalamus and anterior cingulate cortex, while the fast fluctuation component was correlated with the lateral part of the thalamus and the anterior cingulate cortex, but not the brain stem. In summary, these data suggest that different subcortical structures contribute to slow and fast modulations of alpha spectra on brain EEG.

Omata, Kei; Hanakawa, Takashi; Morimoto, Masako; Honda, Manabu

2013-01-01

25

Mobile phone emission modulates interhemispheric functional coupling of EEG alpha rhythms.  

PubMed

We tested the working hypothesis that electromagnetic fields from mobile phones (EMFs) affect interhemispheric synchronization of cerebral rhythms, an important physiological feature of information transfer into the brain. Ten subjects underwent two electroencephalographic (EEG) recordings, separated by 1 week, following a crossover double-blind paradigm in which they were exposed to a mobile phone signal (global system for mobile communications; GSM). The mobile phone was held on the left side of the subject head by a modified helmet, and orientated in the normal position for use over the ear. The microphone was orientated towards the corner of the mouth, and the antenna was near the head in the parietotemporal area. In addition, we positioned another similar phone (but without battery) on the right side of the helmet, to balance the weight and to prevent the subject localizing the side of GSM stimulation (and consequently lateralizing attention). In one session the exposure was real (GSM) while in the other it was Sham; both sessions lasted 45 min. Functional interhemispheric connectivity was modelled using the analysis of EEG spectral coherence between frontal, central and parietal electrode pairs. Individual EEG rhythms of interest were delta (about 2-4 Hz), theta (about 4-6 Hz), alpha 1 (about 6-8 Hz), alpha 2 (about 8-10 Hz) and alpha 3 (about 10-12 Hz). Results showed that, compared to Sham stimulation, GSM stimulation modulated the interhemispheric frontal and temporal coherence at alpha 2 and alpha 3 bands. The present results suggest that prolonged mobile phone emission affects not only the cortical activity but also the spread of neural synchronization conveyed by interhemispherical functional coupling of EEG rhythms. PMID:17432975

Vecchio, Fabrizio; Babiloni, Claudio; Ferreri, Florinda; Curcio, Giuseppe; Fini, Rita; Del Percio, Claudio; Rossini, Paolo Maria

2007-03-01

26

EEG alpha and cortical inhibition in affective attention.  

PubMed

Recent progress in cognitive neuroscience suggests that alpha activity may reflect selective cortical inhibition involved in signal amplification, rather than neural idling. Unfortunately, these theoretical advances remain largely ignored in affective neuroscience. To address this limitation the present paper proposes a novel research avenue aimed at using alpha to elucidate cortical inhibitory mechanisms involved in affective processes. The proposal is illustrated by developing inhibitory accounts of affective attention and affective tuning phenomena. The emergent predictions were tested using event-related perturbations from 73 students evaluating affective and nonaffective aspects of five types of emotional images. The results revealed that upper alpha power was increased by affective content in general and aversive stimuli in particular from 350 ms at posterior and from 575 ms at central sites. The evaluation task interacted with affective content only at a liberal statistical significance level in late posterior alpha. These results are generally in line with the proposed inhibitory accounts of affective attention and tuning, although the evidence is preliminary rather than conclusive. As confirmation of functional origins of alpha in affect remains beyond the scope of a single study, this paper aims to inspire further extrapolation of the inhibitory account of alpha within affective neuroscience. PMID:23643563

Uusberg, Andero; Uibo, Helen; Kreegipuu, Kairi; Allik, Jüri

2013-07-01

27

The hemodynamic response of the alpha rhythm: an EEG/fMRI study.  

PubMed

EEG was recorded during fMRI scanning of 16 normal controls in resting condition with eyes closed. Time variations of the occipital alpha band amplitudes were correlated to the fMRI signal variations to obtain insight into the hemodynamic correlates of the EEG alpha activity. Contrary to earlier studies, no a priori assumptions were made on the expected shape of the alpha band response function (ARF). The ARF of different brain regions and subjects were explored and compared. It was found that: (1) the ARF of the thalamus is mainly positive. (2) The ARFs at the occipital and left and right parietal points are similar in amplitude and timing. (3) The peak time of the thalamus is a few seconds earlier than that of occipital and parietal cortex. (4) No systematic BOLD activity was found preceding the alpha band activity, although in the two subjects with the strongest alpha band power such correlation was present. (5) There is a strong and immediate positive correlation at the eyeball, and a strong negative correlation at the back of the eye. Furthermore, it was found that in one subject the cortical ARF was positive, contrary to the other subjects. Finally, a cluster analysis of the observed ARF, in combination with a Modulated Sine Model (MSM) fit to the estimated ARF, revealed that within the cortex the ARF peak time shows a spatial pattern that may be interpreted as a traveling wave. The spatial pattern of alpha band response function represents the combined effect of local differences in electrical alpha band activity and local differences in the hemodynamic response function (HRF) onto these electrical activities. To disentangle the contributions of both factors, more advanced integration of EEG inverse modeling and hemodynamic response modeling is required in future studies. PMID:17336548

de Munck, J C; Gonçalves, S I; Huijboom, L; Kuijer, J P A; Pouwels, P J W; Heethaar, R M; Lopes da Silva, F H

2007-04-15

28

Event-related EEG theta and alpha band oscillatory responses during language translation  

Microsoft Academic Search

Recent investigations on oscillatory EEG dynamics by means of event-related synchronisation and desynchronisation (ERS\\/ERD) suggest that first language semantic information processing is primarily reflected in the theta (4–7Hz) and alpha (7–13Hz) frequency bands. In this pilot study we explore whether similar ERS\\/ERD patterns emerge during language translation and which frequency bands sensitively respond to the difficulty of translation and the

Roland H. Grabner; Clemens Brunner; Robert Leeb; Christa Neuper; Gert Pfurtscheller

2007-01-01

29

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

30

EEG Alpha Rhythm Frequency and Intelligence in Normal Adults.  

ERIC Educational Resources Information Center

Scores on Raven's Progressive Matrices correlated positively with electroencephalogram-recorded alpha rhythm frequency (AF) in 101 healthy male adults, as did one test of verbal ability and one of mental performance. However, AF did not show significant relationships with general intelligence or spatial and arithmetic abilities. (SLD)

Anokhin, Andrey; Vogel, Friedrich

1996-01-01

31

Tracking EEG changes in response to alpha and beta binaural beats.  

PubMed

A binaural beat can be produced by presenting two tones of a differing frequency, one to each ear. Such auditory stimulation has been suggested to influence behaviour and cognition via the process of cortical entrainment. However, research so far has only shown the frequency following responses in the traditional EEG frequency ranges of delta, theta and gamma. Hence a primary aim of this research was to ascertain whether it would be possible to produce clear changes in the EEG in either the alpha or beta frequency ranges. Such changes, if possible, would have a number of important implications as well as potential applications. A secondary goal was to track any observable changes in the EEG throughout the entrainment epoch to gain some insight into the nature of the entrainment effects on any changes in an effort to identify more effective entrainment regimes. Twenty two healthy participants were recruited and randomly allocated to one of two groups, each of which was exposed to a distinct binaural beat frequency for ten 1-minute epochs. The first group listened to an alpha binaural beat of 10Hz and the second to a beta binaural beat of 20Hz. EEG was recorded from the left and right temporal regions during pre-exposure baselines, stimulus exposure epochs and post-exposure baselines. Analysis of changes in broad-band and narrow-band amplitudes, and frequency showed no effect of binaural beat frequency eliciting a frequency following effect in the EEG. Possible mediating factors are discussed and a number of recommendations are made regarding future studies, exploring entrainment effects from a binaural beat presentation. PMID:23085086

Vernon, D; Peryer, G; Louch, J; Shaw, M

2014-07-01

32

Correlation between quantitative-EEG alterations and age in patients with interferon-alpha-treated hepatitis C.  

PubMed

The authors recently observed alterations in the quantitative EEG findings in patients with chronic hepatitis C who were treated with interferon-alpha (IFN-alpha). However, the factors that influenced such EEG alterations remain unclear. The authors evaluated the correlation between QEEG alterations that occurred during IFN-alpha treatment and the age of 98 patients with chronic hepatitis C. These patients underwent blind, prospective, and serial quantitative EEG examinations. IFN-alpha was administered intramuscularly at 9 x 10 IU daily for the first 4 weeks and then three times per week for the next 20 weeks. Serial EEGs were obtained before, at 2 and 4 weeks, and at 2 to 3 days after the treatment. The absolute powers of each frequency band at different stages of the treatment were determined by QEEG. The ages of the patients were classified into five groups: 20 to 29, 30 to 39, 40 to 49, 50 to 59, and > or =60 years. The relationship between the alterations in power values and age was statistically evaluated. As the age of the patients increased, the alterations in power values for the slow waves, alpha 2, and fast waves during IFN-alpha treatment became more remarkable, and significant (repeated-measure analysis of variance; P < 0.0001). The alterations of EEG occurring during IFN-alpha treatment were marked in older patients. PMID:15689713

Kamei, Satoshi; Oga, Kentaro; Matsuura, Masato; Tanaka, Naohide; Kojima, Takuya; Arakawa, Yasuyuki; Matsukawa, Yoshihiro; Mizutani, Tomohiko; Sakai, Teiichiro; Ohkubo, Hitoshi; Matsumura, Hiroshi; Moriyama, Mitsuhiko; Hirayanagi, Kaname

2005-01-01

33

Contribution of neurophysiological endophenotype, individual frequency of EEG alpha oscillations, to mechanisms of emotional reactivity.  

PubMed

We studied the relationship between individual alpha frequency (IAF) of EEG (neurophysiological endophenotype reflecting individual predisposition to efficacious cognitive and creative activity) and individual emotional reactivity. The psychophysiological study included healthy men in two models of evoked emotions - anxious apprehension (awaiting of inescapable aversive punishment) and discrete (opposite) emotions. Analysis of self-report, multichannel EEG, galvanic skin response, and cardiovascular reactivity showed that individuals with high IAF are characterized by predominance of parasympathetic influences in autonomic regulation circuit, proactive strategies of coping with inescapable threat, higher activity of positive emotional attitude and availability of memory traces about positive experience. Individuals with low IAF demonstrate predominance of sympathetic influences and maladaptive avoidance-like coping with inescapable threat and insufficiency of positive emotional activation mechanisms. It is suggested that IAF participates in the formation of individual emotional space and strategies of coping with emotional challenges. PMID:24824678

Tumyalis, A V; Aftanas, L I

2014-04-01

34

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

35

Validation of a neurofeedback paradigm: Manipulating frontal EEG alpha-activity and its impact on mood.  

PubMed

It is claimed that neurofeedback (NF) is an effective treatment for a variety of psychiatric disorders. NF, within an operant conditioning framework, helps individuals to regulate cortical electroencephalographic (EEG) activity while receiving feedback from a visual or acoustic signal. For example, changing asymmetry between left and right frontal brain alpha activity by NF, is claimed to be an efficacious treatment for major depressive disorder. However, the specificity of this intervention in occasioning electrophysiological changes at target locations and target wave-frequencies, and its relation to changes in mood, has not been established. During a single session of NF, it was tested if the balance between left and right frontal alpha-activity could be changed, regardless of direction, in 40 healthy females. Furthermore, we investigated whether this intervention was electrophysiologically specific and if it was associated with changes in mood. Participants were able to decrease or increase frontal alpha-asymmetry during the intervention. However, no changes in mood were observed. Changes in EEG activity were specific in terms of location and wave-frequency. PMID:23773999

Peeters, Frenk; Ronner, Jacco; Bodar, Lonneke; van Os, Jim; Lousberg, Richel

2014-07-01

36

ADHD Familial Loading and Abnormal EEG Alpha Asymmetry in Children with ADHD1  

PubMed Central

Objective Abnormal brain laterality (ABL) is indicated in ADHD. ADHD and brain laterality are heritable. Genetic factors contributing to lateralization of brain function may contribute to ADHD. If so, increased ADHD family loading should be associated with greater ABL. Previous studies have shown increased rightward alpha asymmetry in ADHD. We tested whether this was more pronounced in ADHD children with increased ADHD family loading. Methods We compared EEG alpha asymmetry at rest and during the Conner’s Continuous Performance Test (CPT) in ADHD children with and without ADHD affected parents, and replicated our findings in a second larger sample. The replication study additionally stratified the parent-affected sample by parental persistent versus non-persistent ADHD status, increased spatial resolution of EEG measures, and assessed low versus high alpha. Results Study-1: The parent-affected group showed increased rightward asymmetry across frontal and central regions and reduced rightward parietal asymmetry during an eyes closed (EC) condition, as well as increasing rightward parietal asymmetry with advancing age during the CPT. Study-2 replicated these findings and further delineated influences of low versus high alpha, recording site, and effects of parental persistent versus non-persistent ADHD status. Conclusion Increased ADHD familial loading was associated with increased rightward frontal asymmetry. In contrast, increased rightward parietal asymmetry was associated with reduced ADHD family loading. Frontal results are consistent with an ADHD endophenotype. Parietal results suggest an ADHD adaptive trait prevalent with less ADHD family loading. Age effects indicate a unique developmental course among ADHD children whose parents have non-persistent ADHD.

Hale, T. Sigi; Smalley, Susan L.; Dang, Jeff; Hanada, Grant; Macion, James; Loo, Sandra K.

2010-01-01

37

Event-related EEG theta and alpha band oscillatory responses during language translation.  

PubMed

Recent investigations on oscillatory EEG dynamics by means of event-related synchronisation and desynchronisation (ERS/ERD) suggest that first language semantic information processing is primarily reflected in the theta (4-7 Hz) and alpha (7-13 Hz) frequency bands. In this pilot study we explore whether similar ERS/ERD patterns emerge during language translation and which frequency bands sensitively respond to the difficulty of translation and the translation success. Thirteen female students of translation and interpreting were visually presented high and low frequency English words that had to be translated into German. Time-frequency representations of ERS/ERD between 2 and 50 Hz displayed a theta ERS response about 200-600 ms after word presentation, a beta ERD from about 400 ms, and alpha ERS and ERD patterns about 200-400 ms after word presentation. Statistical analyses of the ERS/ERD data in the theta (4-7 Hz), two alpha frequency bands (7-10 Hz and 10-13 Hz), and a beta band (20-30 Hz) predominantly revealed: (a) higher parietal theta ERS and frontal upper alpha ERD during the translation of low as compared to high frequency words, and (b) generally stronger ERD in the lower alpha band and larger left-hemispheric upper alpha ERD for successfully translated in contrast to not translated low frequency words. These findings provide first evidence of the sensitivity of the theta and alpha ERS/ERD measure to lexical-semantic processes involved in language translation. PMID:17303508

Grabner, Roland H; Brunner, Clemens; Leeb, Robert; Neuper, Christa; Pfurtscheller, Gert

2007-04-01

38

[The relationship of visual illusions to the frequency and phase shift of rhythmic photostimulation synchronized with the EEG alpha wave].  

PubMed

Under flicker stimulation through the closed eyes, synchronized with different phases of the EEG alpha wave, all 18 subjects systematically perceived the illusory visual objects (ring, circle, spiral, or curvilinear grid). Most frequently, they saw a ring or a circle, a little less frequently, a three-dimensional spiral, and at last-a curvilinear grid. The incidence of the ring and spiral illusion was the highest when the stimulation frequency strictly coincided with the individual dominant frequency of the alpha-rhythm. On the contrary, the grid illusion appeared more frequently when the stimulation frequency differed from that of the alpha-rhythm by 1-2 Hz. No significant effect was found of the alpha wave phase, which triggered the photostimulation, on the probability of the illusion perception. The revealed phenomena are probably explained by summation of the spreading alpha wave (the "scanning" hypothesis) with the isorhythmical afferent excitation evoked by flashes due to the quasi-stroboscopic effect. PMID:9273785

Kamenkovich, V M; Bark, E D; Shevelev, I A; Sharaev, G A

1997-01-01

39

Association between COMT Val158Met genotype and EEG alpha peak frequency tested in two independent cohorts.  

PubMed

This study could not confirm the association between the Catechol-O-Methyltransferase Val158Met polymorphism (COMT) and electroencephalographic (EEG) alpha peak frequency (APF) in two independent cohorts of 187 (96 depressed and 91 healthy participants) and 413 healthy participants. If COMT and APF play a role in depression or antidepressant treatment response, they do not have a shared pathway. We emphasize the importance of publishing null-findings for obtaining more accurate overall estimates of genetic effects. PMID:24889847

Veth, Cornelis P M; Arns, Martijn; Drinkenburg, Wilhelmus; Talloen, Willem; Peeters, Pieter J; Gordon, Evian; Buitelaar, Jan K

2014-09-30

40

Effects of Instructions and Biofeedback on EEG-Alpha Production and the Effects of EEG-Alpha Biofeedback Training for Controlling Arousal in a Subsequent Stressful Situation.  

ERIC Educational Resources Information Center

Results indicate that the instructions (and related information concerning alpha) rather than the biofeedback are critical in alpha biofeedback training and that this training does not appear to have utility for controlling arousal under stress. (Author)

Holmes, David S.; And Others

1980-01-01

41

EEG upper/low alpha frequency power ratio relates to temporo-parietal brain atrophy and memory performances in mild cognitive impairment  

PubMed Central

Objective: Temporo-parietal cortex thinning is associated to mild cognitive impairment (MCI) due to Alzheimer disease (AD). The increase of EEG upper/low alpha power ratio has been associated with AD-converter MCI subjects. We investigated the association of alpha3/alpha2 ratio with patterns of cortical thickness in MCI. Materials and Methods: Seventy-four adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording and high resolution 3D magnetic resonance imaging. Alpha3/alpha2 power ratio as well as cortical thickness was computed for each subject. Three MCI groups were detected according to increasing tertile values of upper/low alpha power ratio. Difference of cortical thickness among the groups was estimated. Pearson’s r was used to assess the topography of the correlation between cortical thinning and memory impairment. Results: High upper/low alpha power ratio group had total cortical gray matter volume reduction of 471 mm2 than low upper/low alpha power ratio group (p < 0.001). Upper/low alpha group showed a similar but less marked pattern (160 mm2) of cortical thinning when compared to middle upper/low alpha power ratio group (p < 0.001). Moreover, high upper/low alpha group had wider cortical thinning than other groups, mapped to the Supramarginal and Precuneus bilaterally. Finally, in high upper/low alpha group temporo-parietal cortical thickness was correlated to memory performance. No significant cortical thickness differences was found between middle and low alpha3/alpha2 power ratio groups. Conclusion: High EEG upper/low alpha power ratio was associated with temporo-parietal cortical thinning and memory impairment in MCI subjects. The combination of EEG upper/low alpha ratio and cortical thickness measure could be useful for identifying individuals at risk for progression to AD dementia and may be of value in clinical context.

Moretti, Davide V.; Paternico, Donata; Binetti, Giuliano; Zanetti, Orazio; Frisoni, Giovanni B.

2013-01-01

42

Different slopes for different folks: alpha and delta EEG power predict subsequent video game learning rate and improvements in cognitive control tasks.  

PubMed

We hypothesized that control processes, as measured using electrophysiological (EEG) variables, influence the rate of learning of complex tasks. Specifically, we measured alpha power, event-related spectral perturbations (ERSPs), and event-related brain potentials during early training of the Space Fortress task, and correlated these measures with subsequent learning rate and performance in transfer tasks. Once initial score was partialled out, the best predictors were frontal alpha power and alpha and delta ERSPs, but not P300. By combining these predictors, we could explain about 50% of the learning rate variance and 10%-20% of the variance in transfer to other tasks using only pretraining EEG measures. Thus, control processes, as indexed by alpha and delta EEG oscillations, can predict learning and skill improvements. The results are of potential use to optimize training regimes. PMID:23095124

Mathewson, Kyle E; Basak, Chandramallika; Maclin, Edward L; Low, Kathy A; Boot, Walter R; Kramer, Arthur F; Fabiani, Monica; Gratton, Gabriele

2012-12-01

43

Resting and task-elicited prefrontal EEG alpha asymmetry in depression: support for the capability model.  

PubMed

The capability model of frontal electroencephalographic (EEG) asymmetry suggests that brain activity during emotional challenge will be a more powerful indicator of predispositions toward psychopathology than activity observed at rest. EEG data were assessed during a resting baseline and a facial emotion task, wherein individuals with (n = 143) and without (n = 163) lifetime major depressive disorder (MDD) made approach (angry and happy) and withdrawal (afraid and sad) facial expressions. EEG asymmetry during emotional challenge was a more powerful indicator of MDD status than resting asymmetry for average, Cz, and linked mastoid references, results in support of the capability model. However, current-source-density (CSD) transformed asymmetry was indicative of lifetime MDD status under resting and task-elicited conditions. Findings suggest that CSD-transformed data may be more robust indicators of trait frontal EEG asymmetry. PMID:24611480

Stewart, Jennifer L; Coan, James A; Towers, David N; Allen, John J B

2014-05-01

44

Genetic and Environmental Influences on Frontal EEG Asymmetry and Alpha Power in 9-10 Year Old Twins  

PubMed Central

Modest genetic influences on frontal EEG asymmetry have been found in adults, but little is known about its genetic origins in children. Resting frontal asymmetry and alpha power were examined in 951 9–10-year-old twins. Results showed that in both males and females: (1) a modest but significant amount of variance in frontal asymmetry was accounted for by genetic factors (11–27%) with the remainder accounted for by non-shared environmental influences, and (2) alpha power were highly heritable, with 70–85% of the variance accounted for by genetic factors. Results suggest that the genetic architecture of frontal asymmetry and alpha power in late childhood are similar to that in adulthood and that the high non-shared environmental influences on frontal asymmetry may reflect environmentally-influenced individual differences in the maturation of frontal cortex as well as state-dependent influences on specific measurements.

Gao, Yu; Tuvblad, Catherine; Raine, Adrian; Lozano, Dora I.; Baker, Laura A.

2008-01-01

45

Development of psychomotor tempó (tapping speed and stability) and EEG alpha frequency in 7 to 15-years-old children.  

PubMed

The psychomotor tempo (tapping) and its relation to alpha frequency was investigated in 100 7- to 15-year-old children. The frequency of alpha rhythm increased in proportion to age, and the maximum and preferential tapping frequencies revealed an increasing tendency, too. Mainly the preferential tapping frequency correlated with the age-dependent increment of EEG alpha frequency. Simultaneously, the variability of the tapping frequency decreased. During a phase of relatively stable tapping performance regular fluctuations in the tapping frequency occurred with a period duration between 0.67 and 13.3 s. These oscillations of the motor activity developed during ontogenesis: The slow fluctuations were found in all groups, whereas those with shorter periods were best pronounced in the older children. The development of EEG and psychomotor indices are assumed to be based on the morphological and functional maturation of the developing brain. Therefore, they may be used as a tool to assess the normal and disturbed brain development. PMID:4060987

Roth, N; Wündrich, B; Pögelt, B

1985-09-01

46

Sensitivity of alpha and beta oscillations to sensorimotor characteristics of action: an EEG study of action production and gesture observation.  

PubMed

The sensorimotor experiences we gain when performing an action have been found to influence how our own motor systems are activated when we observe others performing that same action. Here we asked whether this phenomenon applies to the observation of gesture. Would the sensorimotor experiences we gain when performing an action on an object influence activation in our own motor systems when we observe others performing a gesture for that object? Participants were given sensorimotor experience with objects that varied in weight, and then observed video clips of an actor producing gestures for those objects. Electroencephalography (EEG) was recorded while participants first observed either an iconic gesture (pantomiming lifting an object) or a deictic gesture (pointing to an object) for an object, and then grasped and lifted the object indicated by the gesture. We analyzed EEG during gesture observation to determine whether oscillatory activity was affected by the observer's sensorimotor experiences with the object represented in the gesture. Seeing a gesture for an object previously experienced as light was associated with a suppression of power in alpha and beta frequency bands, particularly at posterior electrodes. A similar pattern was found when participants lifted the light object, but over more diffuse electrodes. Moreover, alpha and beta bands at right parieto-occipital electrodes were sensitive to the type of gesture observed (iconic vs. deictic). These results demonstrate that sensorimotor experience with an object affects how a gesture for that object is processed, as measured by the gesture-observer's EEG, and suggest that different types of gestures recruit the observer's own motor system in different ways. PMID:22910276

Quandt, Lorna C; Marshall, Peter J; Shipley, Thomas F; Beilock, Sian L; Goldin-Meadow, Susan

2012-10-01

47

Distribution of alpha 1-antitrypsin (PI) phenotypes in chromosome abnormalities.  

PubMed

PI phenotypes (including subtypes) were determined for 168 individuals with chromosomal abnormalities ascertained in Adelaide. These included patients with mosaicism, trisomy 21, trisomy 13, trisomy 18, and various sex chromosome aberrations (45,X, 47,XXX, 47,XXY, 47, XYY, and 48,XXXY). Data did not support an existing proposition that mildly deficient PI phenotypes predispose to abnormal chromosome segregation during mitosis of meiosis. Phenotypic distributions of each group were statistically similar to control populations of cord bloods and bloods donors. PMID:6971795

Mulley, J C; Sutherland, G R

1981-01-01

48

EEG alpha oscillations during the performance of verbal creativity tasks: differential effects of sex and verbal intelligence.  

PubMed

Task-related power changes in the EEG alpha band were analyzed in 31 participants (17 males and 14 females) during performance of two verbal creativity tasks. Participants were confronted with verbal problems that are in need of explanation (insight problems) and utopian situations that will actually never happen. In both tasks they were instructed to generate as many but also as unusual, unique or original ideas as possible. To assess brain responses that come along with highly original ideas, individual responses were divided into more and less original ideas (within each participant). Creative problem solving was generally accompanied by lower levels of cortical arousal (i.e., increases in alpha power from a pre-stimulus reference to an activation interval). Additionally, more original (vs. less original) responses were associated with a stronger task-related alpha synchronization in posterior (particularly centroparietal) cortices. Task-related alpha power changes during creative problem solving were also moderated by verbal IQ and sex. PMID:16503062

Fink, Andreas; Neubauer, Aljoscha C

2006-10-01

49

Modulation of t1alpha expression with alveolar epithelial cell phenotype in vitro.  

PubMed

T1alpha is a recently identified gene expressed in the adult rat lung by alveolar type I (AT1) epithelial cells but not by alveolar type II (AT2) epithelial cells. We evaluated the effects of modulating alveolar epithelial cell (AEC) phenotype in vitro on T1alpha expression using either soluble factors or changes in cell shape to influence phenotype. For studies on the effects of soluble factors on T1alpha expression, rat AT2 cells were grown on polycarbonate filters in serum-free medium (MDSF) or in MDSF supplemented with either bovine serum (BS, 10%), rat serum (RS, 5%), or keratinocyte growth factor (KGF, 10 ng/ml) from either day 0 or day 4 through day 8 in culture. For studies on the effects of cell shape on T1alpha expression, AT2 cells were plated on thick collagen gels in MDSF supplemented with BS. Gels were detached on either day 1 (DG1) or day 4 (DG4) or were left attached until day 8. RNA and protein were harvested at intervals between days 1 and 8 in culture, and T1alpha expression was quantified by Northern and Western blotting, respectively. Expression of T1alpha progressively increases in AEC grown in MDSF +/- BS between day 1 and day 8 in culture, consistent with transition toward an AT1 cell phenotype. Exposure to RS or KGF from day 0 prevents the increase in T1alpha expression on day 8, whereas addition of either factor from day 4 through day 8 reverses the increase. AEC cultured on attached gels express high levels of T1alpha on days 4 and 8. T1alpha expression is markedly inhibited in both DG1 and DG4 cultures, consistent with both inhibition and reversal of the transition toward the AT1 cell phenotype. These results demonstrate that both soluble factors and alterations in cell shape modulate T1alpha expression in parallel with AEC phenotype and provide further support for the concept that transdifferentiation between AT2 and AT1 cell phenotypes is at least partially reversible. PMID:9688947

Borok, Z; Danto, S I; Lubman, R L; Cao, Y; Williams, M C; Crandall, E D

1998-07-01

50

Simplified alpha1-antitrypsin phenotyping by immunofixation of acid-starch gels.  

PubMed

Immunofixation of acid-starch gels represents a simplified method for alpha1-antitrypsin phenotyping. This technique reduces the amount of work and time involved in phenotyping by eliminating the need for crossed-immunoelectrophoresis. Its major purpose is to directly enhance the staining quality of the minor bands, especially the Z bands on the acid-starch gel. It is hoped that this modified method will allow more wide-spread use of antitrypsin phenotyping, especially in the routine clinical chemistry laboratory. PMID:1083884

Lieberman, J; Gaidulis, L

1976-04-01

51

The impact of audio-visual stimulation on alpha brain oscillations: An EEG study  

Microsoft Academic Search

Many studies investigated the brain responses as a reaction in auditory or visual stimuli separately. However a few studies have been published so far investigating the interactions of the two aforementioned stimuli. The current study comes to examine the impact of the audio-visual stimulation with binaural beats and flickering light in four different colors on low and upper alpha oscillations.

Christos N. Moridis; Manousos A. Klados; Ioannis A. Kokkinakis; Vasileios Terzis; Anastasios A. Economides; Anna Karlovasitou; Panagiotis D. Bamidis; Vasileios E. Karabatakis

2010-01-01

52

An empirical study on the relations between EEG alpha-beta entropy & EQ- IQ test scores  

Microsoft Academic Search

In this paper, the relationship between the subjects' brain waves and the relative Emotional Quotient (EQ) and Intelligence Quotient (IQ) has been investigated. In this study, the intensity of correlation between the entropy of Alpha and Beta brain waves and the IQ and EQ has been evaluated over thirty healthy subjects (15 males, 15 females, and aged 21–25 year old)

Sarah Vakili; Nima Tehranchian; Maryam Tajziehchi; Iman Mohammad Rezazadeh; Xiangyu Wang

2012-01-01

53

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

54

Negative Covariation between Task-related Responses in Alpha/Beta-Band Activity and BOLD in Human Sensorimotor Cortex: an EEG and fMRI Study of Motor Imagery and Movements  

PubMed Central

Similar to the occipital alpha rhythm, electroencephalographic (EEG) signals in the alpha- and beta-frequency bands can be suppressed by movement or motor imagery and have thus been thought to represent the “idling state” of the sensorimotor cortex. A negative correlation between spontaneous alpha EEG and blood-oxygen-level-dependent (BOLD) signals has been reported in combined EEG and fMRI (functional Magnetic Resonance Imaging) experiments when subjects stayed at the resting state or alternated between the resting state and a task. However, the precise nature of the task-induced alpha modulation remains elusive. It was not clear whether alpha/beta rhythm suppressions may co-vary with BOLD when conducting tasks involving varying activations of the cortex. Here, we quantified the task-evoked responses of BOLD and alpha/beta-band power of EEG directly in the cortical source domain, by using source imaging technology, and examined their covariation across task conditions in a mixed block and event-related design. In this study, 13 subjects performed tasks of right hand, right foot or left hand movement and motor imagery when EEG and fMRI data were separately collected. Task-induced increase of BOLD signal and decrease of EEG amplitudes in alpha and beta bands were shown to be co-localized at the somatotopic sensorimotor cortex. At the corresponding regions, the reciprocal changes of the two signals co-varied in the magnitudes across imagination and movement conditions. The spatial correspondence and negative covariation between the two measurements was further shown to exist at somatotopic brain regions associated with different body parts. These results suggest an inverse functional coupling between task-induced changes of BOLD and low-frequency EEG signals.

Yuan, Han; Liu, Tao; Szarkowski, Rebecca; Rios, Cristina; Ashe, James; He, Bin

2009-01-01

55

Alpha-locus hexosaminidase genetic compound with juvenile gangliosidosis phenotype: clinical, genetic, and biochemical studies.  

PubMed Central

A 3-year-old boy developed progressive neurological deterioration in his third year, characterized by dementia, ataxia, myoclonic jerks, and bilateral macular cherry-red spots. Hexosaminidase A (HEX A) was partially decreased in the patient's serum, leukocytes, and cultured skin fibroblasts. Hexosaminidase was studied in serum and leukocytes from family members. Four members of the paternal branch appeared to be carriers of classical infantile Tay-Sachs allele, HEX alpha 2, probably receiving the gene from one great-grandparent of Ashkenazi origin. In the maternal branch, no one was a carrier of classical infantile Tay-Sachs disease, but five individuals were carriers of a milder alpha-locus defect. The patient, therefore, was a genetic compound of two different alpha-locus hexosaminidase mutations. At least 21 families with late-infantile or juvenile GM2 gangliosidosis have been reported, 18 of them with alpha-locus mutations, and three with beta-locus mutations. Genetic compounds of hexosaminidase have been reported in at least seven families, five with alpha-locus mutations and two with beta-locus mutations. The compound had the phenotype of infantile Tay-Sachs disease in one family, infantile Sandhoff disease in another, and the normal phenotype in the rest.

Johnson, W G; Cohen, C S; Miranda, A F; Waran, S P; Chutorian, A M

1980-01-01

56

Prenatal skeletal dysplasia phenotype in severe MLII alpha/beta with novel GNPTAB mutation.  

PubMed

We report a neonate who was diagnosed as a case of skeletal dysplasia during pregnancy, and was subsequently diagnosed as a case of MLII alpha/beta on the basis of clinical and radiological findings and molecular testing of the parents. A novel GNPTAB mutation c.1701delC [p.F566LfsX5] was identified in the father. The case reiterates the severe prenatal phenotype of MLII alpha/beta which mimics skeletal dysplasia and illustrates the utility of molecular genetic analysis in confirmation of diagnosis and subsequent genetic counselling. PMID:24685522

Aggarwal, Shagun; Coutinho, Maria Francisca; Dalal, Ashwin B; Mohamed Nurul Jain, S Jamal; Prata, Maria João; Alves, Sandra

2014-06-01

57

MeCP2+/- mouse model of RTT reproduces auditory phenotypes associated with Rett syndrome and replicate select EEG endophenotypes of autism spectrum disorder.  

PubMed

Impairments in cortical sensory processing have been demonstrated in Rett syndrome (RTT) and Autism Spectrum Disorders (ASD) and are thought to contribute to high-order phenotypic deficits. However, underlying pathophysiological mechanisms for these abnormalities are unknown. This study investigated auditory sensory processing in a mouse model of RTT with a heterozygous loss of MeCP2 function. Cortical abnormalities in a number of neuropsychiatric disorders, including ASD are reflected in auditory evoked potentials and fields measured by EEG and MEG. One of these abnormalities, increased latency of cortically sourced components, is associated with language and developmental delay in autism. Additionally, gamma-band abnormalities have recently been identified as an endophenotype of idiopathic autism. Both of these cortical abnormalities are potential clinical endpoints for assessing treatment. While ascribing similar mechanisms of idiopathic ASD to Rett syndrome (RTT) has been controversial, we sought to determine if mouse models of RTT replicate these intermediate phenotypes. Mice heterozygous for the null mutations of the gene MeCP2, were implanted for EEG. In response to auditory stimulation, these mice recapitulated specific latency differences as well as select gamma and beta band abnormalities associated with ASD. MeCP2 disruption is the predominant cause of RTT, and reductions in MeCP2 expression predominate in ASD. This work further suggests a common cortical pathophysiology for RTT and ASD, and indicates that the MeCP2+/- model may be useful for preclinical development targeting specific cortical processing abnormalities in RTT with potential relevance to ASD. PMID:22249109

Liao, Wenlin; Gandal, Michael J; Ehrlichman, Richard S; Siegel, Steven J; Carlson, Greg C

2012-04-01

58

Neutralizing TNF-alpha activity modulates T-cell phenotype and function in experimental autoimmune uveoretinitis.  

PubMed

Inhibiting TNF-alpha activity prevents tissue destruction without inhibiting retinal T cell infiltration in experimental autoimmune uveoretinitis (EAU) in Lewis rats. To further determine the role of TNF-alpha in autoimmune uveitis we characterized T cells isolated from retinae after treatment with a TNF-alpha antagonist. TNF-alpha activity was neutralized in vivo with a p55 TNF-alpha receptor-Ig fusion protein (sTNFr-Ig), administered 8 and 10 days after induction of EAU with heterologous retinal antigens. Retinal T-cell phenotype expression was examined by flow cytometry with respect to OX22 status (CD45RBlow or CD45RBhigh), activation (OX40 and CD25 expression) and rate of T-cell apoptosis (Annexin V+PI- expression). Lymphocyte reactivity was assessed by proliferation responses and cytokine production to retinal antigens. Despite greater than 40% of CD4+ T cells being activated at the height of disease, the proportion of OX22low expression was reduced and T cells exhibited reduced IFN-gamma and elevated IL-4 production. Retinal T cells maintained antigen-specific proliferation and demonstrated a low apoptotic rate. Although in both animal groups, comparable numbers of T cells were isolated, neutralizing TNF activity suppressed Th1 effector mechanisms protecting against target organ damage. PMID:9693974

Dick, A D; Duncan, L; Hale, G; Waldmann, H; Isaacs, J

1998-06-01

59

HIF-1{alpha} Mediates Tumor Hypoxia to Confer a Perpetual Mesenchymal Phenotype for Malignant Progression  

NSDL National Science Digital Library

Although tumor progression involves genetic and epigenetic alterations to normal cellular biology, the underlying mechanisms of these changes remain obscure. Numerous studies have shown that hypoxia-inducible factor 1&alpha; (HIF-1&alpha;) is overexpressed in many human cancers and up-regulates a host of hypoxia-responsive genes for cancer growth and survival. We recently identified an alternative mechanism of HIF-1&alpha; function that induces genetic alterations by suppressing DNA repair. Here, we show that long-term hypoxia, which mimics the tumor microenvironment, drives a perpetual epithelial-mesenchymal transition (EMT) through up-regulation of the zinc finger E-box binding homeobox protein ZEB2, whereas short-term hypoxia induces a reversible EMT that requires the transcription factor Twist1. Moreover, we show that the perpetual EMT driven by chronic hypoxia depends on HIF-1&alpha; induction of genetic alterations rather than its canonical transcriptional activator function. These mesenchymal tumor cells not only acquire tumorigenicity but also display characteristics of advanced cancers, including necrosis, aggressive invasion, and metastasis. Hence, these results reveal a mechanism by which HIF-1&alpha; promotes a perpetual mesenchymal phenotype, thereby advancing tumor progression.

Young-Gun Yoo (University of Utah;Department of Neurosurgery REV); Jared Christensen (University of Utah;Department of Neurosurgery REV); Jie Gu (University of Utah;Department of Neurosurgery REV); L. Eric Huang (University of Utah;Department of Neurosurgery REV)

2011-06-21

60

"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.

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

2014-01-01

61

Embryonic endocrine pancreas and mature beta cells acquire alpha and PP cell phenotypes upon Arx misexpression.  

PubMed

Aristaless-related homeobox (Arx) was recently demonstrated to be involved in pancreatic alpha cell fate specification while simultaneously repressing the beta and delta cell lineages. To establish whether Arx is not only necessary, but also sufficient to instruct the alpha cell fate in endocrine progenitors, we used a gain-of-function approach to generate mice conditionally misexpressing this factor. Mice with forced Arx expression in the embryonic pancreas or in developing islet cells developed a dramatic hyperglycemia and eventually died. Further analysis demonstrated a drastic loss of beta and delta cells. Concurrently, a remarkable increase in the number of cells displaying alpha cell or, strikingly, pancreatic polypeptide (PP) cell features was observed. Notably, the ectopic expression of Arx induced in embryonic or adult beta cells led to a loss of the beta cell phenotype and a concomitant increase in a number of cells with alpha or PP cell characteristics. Combining quantitative real-time PCR and lineage-tracing experiments, we demonstrate that, in adult mice, the misexpression of Arx, rather than its overexpression, promotes a conversion of beta cells into glucagon- or PP-producing cells in vivo. These results provide important insights into the complex mechanisms underlying proper pancreatic endocrine cell allocation and cell identity acquisition. PMID:17404619

Collombat, Patrick; Hecksher-Sørensen, Jacob; Krull, Jens; Berger, Joachim; Riedel, Dietmar; Herrera, Pedro L; Serup, Palle; Mansouri, Ahmed

2007-04-01

62

Mindfulness-based cognitive therapy (MBCT), cognitive style, and the temporal dynamics of frontal EEG alpha asymmetry in recurrently depressed patients.  

PubMed

Mindfulness-based cognitive therapy (MBCT), a meditation-based maintenance therapy, reduces the relapse risk in individuals suffering from major depressive disorder (MDD). However, only a few studies investigated the psychophysiological mechanisms underlying this protective effect. We examined effects of MBCT on trait rumination and mindfulness, as indicators of global cognitive style, as well as on residual depressive symptoms in a group of recurrently depressed patients (n=78) in remission. Additionally, alpha asymmetry in resting-state electroencephalogram (EEG) was assessed. Alpha asymmetry has been found to be predictive of affective style and a pattern indicative of stronger relative right-hemispheric anterior cortical activity may represent a trait marker for the vulnerability to develop MDD. In line with previous findings, residual depressive symptoms and trait rumination decreased, whereas trait mindfulness increased following MBCT, while no such changes took place in a wait-list control group. Mean values of alpha asymmetry, on the other hand, remained unaffected by training, and shifted systematically toward a pattern indicative of stronger relative right-hemispheric anterior cortical activity in the whole sample. These findings provide further support for the protective effect of MBCT. In the examined patients who were at an extremely high risk for relapse, however, this effect did not manifest itself on a neurophysiological level in terms of alpha asymmetry, where a shift, putatively indicative of increased vulnerability, was observed. PMID:21884751

Keune, Philipp M; Bostanov, Vladimir; Hautzinger, Martin; Kotchoubey, Boris

2011-12-01

63

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.

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

2011-01-01

64

Prestimulus oscillations in the alpha band of the EEG are modulated by the difficulty of feature discrimination and predict activation of a sensory discrimination process.  

PubMed

Recent work has demonstrated that the occipital-temporal N1 component of the ERP is sensitive to the difficulty of visual discrimination, in a manner that cannot be explained by simple differences in low-level visual features, arousal, or time on task. These observations provide evidence that the occipital-temporal N1 component is modulated by the application of top-down control. However, the timing of this control process remains unclear. Previous work has demonstrated proactive, top-down modulation of cortical excitability for cued spatial attention or feature selection tasks. Here, the possibility that a similar top-down process facilitates performance of a difficult stimulus discrimination task is explored. Participants performed an oddball task at two levels of discrimination difficulty, with difficulty manipulated by modulating the similarity between target and nontarget stimuli. Discrimination processes and cortical excitability were assessed via the amplitude of the occipital-temporal N1 component and prestimulus alpha oscillation of the EEG, respectively. For correct discriminations, prestimulus alpha power was reduced, and the occipital-temporal N1 was enhanced in the hard relative to the easy condition. Furthermore, within the hard condition, prestimulus alpha power was reduced, and the occipital-temporal N1 was enhanced for correct relative to incorrect discriminations. The generation of ERPs contingent on relative prestimulus alpha power additionally suggests that diminished alpha power preceding stimulus onset is related to enhancement of the occipital-temporal N1. As in spatial attention, proactive control appears to enhance cortical excitability and facilitate discrimination performance in tasks requiring nonspatial, feature-based attention, even in the absence of competing stimulus features. PMID:24405187

Roberts, Daniel M; Fedota, John R; Buzzell, George A; Parasuraman, Raja; McDonald, Craig G

2014-08-01

65

The dynamics of EEG entropy.  

PubMed

The scaling properties of human EEG have so far been analyzed predominantly in the framework of detrended fluctuation analysis (DFA). In particular, these studies suggested the existence of power-law correlations in EEG. In DFA, EEG time series are tacitly assumed to be made up of fluctuations, whose scaling behavior reflects neurophysiologically important information and polynomial trends. Even though these trends are physiologically irrelevant, they must be eliminated (detrended) to reliably estimate such measures as Hurst exponent or fractal dimension. Here, we employ the diffusion entropy method to study the scaling behavior of EEG. Unlike DFA, this method does not rely on the assumption of trends superposed on EEG fluctuations. We find that the growth of diffusion entropy of EEG increments of awake subjects with closed eyes is arrested only after approximately 0.5 s. We demonstrate that the salient features of diffusion entropy dynamics of EEG, such as the existence of short-term scaling, asymptotic saturation, and alpha wave modulation, may be faithfully reproduced using a dissipative, first-order, stochastic differential equation-an extension of the Langevin equation. The structure of such a model is utterly different from the "noise+trend" paradigm of DFA. Consequently, we argue that the existence of scaling properties for EEG dynamics is an open question that necessitates further studies. PMID:19669909

Ignaccolo, Massimiliano; Latka, Mirek; Jernajczyk, Wojciech; Grigolini, Paolo; West, Bruce J

2010-03-01

66

Phenotype and Genotype in Mucolipidoses II and III alpha/beta: A Study of 61 Probands  

PubMed Central

Objectives Mucolipidoses II and III alpha/beta (ML II and ML III) are lysosomal disorders in which the essential mannose-6-phosphate recognition marker is not synthesized onto lysosomal hydrolases and other glycoproteins. The disorders are caused by mutations in GNPTAB, which encodes two of three subunits of the heterohexameric enzyme, N-acetylglucosamine-1-phosphotransferase. Clinical, biochemical, and molecular findings in 61 probands (63 patients) are presented in order to provide a broad perspective of these mucolipidoses. Methods GNPTAB was sequenced in all probands and/or parents. Activity of several lysosomal enzymes was measured in plasma, and GlcNac-1-phosphotransferase was assayed in leukocytes. Thirty-six patients were studied in detail, allowing extensive clinical data to be abstracted. Results ML II correlates with near total absence of phosphotransferase activity resulting from homozygosity or compound heterozygosity for frameshift or nonsense mutations. Craniofacial and orthopedic manifestations are evident at birth, skeletal findings become more obvious within the first year, and growth is severely impaired. Speech, ambulation, and cognitive function are impaired. ML III retains a low level of phosphotransferase activity due to at least one missense or splice site mutation. The phenotype is milder with minimal delays in milestones, the appearance of facial coarsening by early school age, and slowing of growth after age four years. Conclusions Fifty-one pathogenic changes in GNPTAB are presented, including 42 novel mutations. Ample clinical information improves criteria for delineation of ML II and ML III. Phenotype-genotype correlations suggested in more general terms in earlier reports on smaller groups of patients are specified and extended.

Cathey, Sara S.; Leroy, Jules G.; Wood, Tim; Eaves, Karisa; Simensen, Richard J.; Kudo, Mariko; Stevenson, Roger E.; Friez, Michael J.

2013-01-01

67

[Theta and alpha-band EEG spatial synchronization under the conditions of visual set, formed to an angry face expression. A study of 5-11-year-old children].  

PubMed

EEG coherence in theta and alpha bands during set-forming and set-shifting was studied in 5-6-year-old (n=18) and 10-11-year-old (n=25) children. Set was formed to visual stimuli (facial photos with emotionally negative expression). Younger children displayed smaller coherence values, especially in the right hemisphere, than older ones. We also revealed differences in theta and alpha band coherence in cases of a rigid and a plastic set. For example, EEG-coherence values were smaller when cognitive processes were relatively rigid (i.e., in a case of a slower set-shifting). A strong correlation between electrophysiological and behavioral data supports the hypothesis that cortico-hippocampal and fronto-thalamic brain integration systems participate in facial expression recognition and provide cognition flexibility. PMID:22117452

Kostandov, É A; Farber, D A; Cheremushkin, N E; Petrenko, N E; Ashkinazi, M L

2011-01-01

68

Heritability of EEG Coherence in a large sib-pair population?  

PubMed Central

The additive genetic heritability of bipolar EEG coherence in a sample of 305 non-twin sibships comprising 690 individuals (age range 7–65) was estimated. Heritabilities were examined in 6 frequency bands for each of 15 coherence pairs, both inter-hemispheric and intrahemispheric. The heritabilities of the bipolar EEG coherence ranged from 0.22 to 0.63 in 79 of the 90 phenotypes which had coherences high enough to provide meaningful values for the estimation of heritability. Heritabilities were greatest in the low and high alpha frequency bands, while theta and beta bands had comparable heritabilities. Coherences themselves were greatest in the low and high alpha frequency bands, while theta coherences were somewhat larger than beta. Higher heritability values were not associated with higher coherences. The examination of bivariate genetic correlations suggests that there is a difference between theta and alpha bands in genetic control of interhemispheric coherence.

Chorlian, David B.; Tang, Yongqiang; Rangaswamy, Madhavi; O'Connor, Sean; Rohrbaugh, John; Taylor, Robert; Porjesz, Bernice

2007-01-01

69

BrainResonance: An EEG-Based System for Human Interaction  

Microsoft Academic Search

BrainResonance is an Electroencephalogram (EEG)-based system proposed to explore the feasibility of using EEG signals for human interaction. EEG signals that measure human brain activities were captured from two users simultaneously in real- time. The correlation values of their EEG alpha and beta rhythms were computed and used to drive a visual feedback system that was in the form of

Zhangbo Liu

70

Adenovirus-mediated hepatocyte nuclear factor-4{alpha} overexpression maintains liver phenotype in cultured rat hepatocytes  

SciTech Connect

Hepatocyte nuclear factor 4{alpha} (HNF-4{alpha}) is a transcription factor that controls embryonal liver development and that maintains and regulates gene expression in adult liver cells. We have previously demonstrated that transient overexpression of HNF-4{alpha} up-regulates a number of liver-specific genes in hepatoma cell lines. In this study, we extend these studies by assessing the functional role of HNF-4{alpha} in regulating cellular viability and liver-specific functions of primary rat hepatocytes. In cells transfected with an adenovirus vector carrying rat HNF-4{alpha} cDNA, induction and maintenance of liver-specific genes and functions were observed over a long-term culture, which might be associated with the prevention of a rapid loss of the mitochondrial membrane potential. In addition, we demonstrated that transthyretin mRNA was up-regulated by HNF-4{alpha} in primary hepatocytes, but not in hepatoma cells. These results indicate that HNF-4{alpha} plays a role in the maintenance of morphologically and biochemically functional hepatocytes and that the difference in expression of liver-specific genes induced by HNF-4{alpha} may depend on a differentiation state of cells.

Naiki, Takafumi [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Nagaki, Masahito [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan)]. E-mail: mnagaki@cc.gifu-u.ac.jp; Asano, Takahiko [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Kimata, Takayuki [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Moriwaki, Hisataka [Department of Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan)

2005-09-23

71

A challenging diagnosis of alpha-1-antitrypsin deficiency: identification of a patient with a novel F/Null phenotype  

PubMed Central

Alpha-1-antitrypsin (A1AT) deficiency is a genetic disease characterized by low levels and/or function of A1AT protein. A1AT deficiency can result in the development of COPD, liver disease, and certain skin conditions. The disease can be diagnosed by demonstrating a low level of A1AT protein and genotype screening for S and Z mutations, which are the most common. However, there are many genetic variants in A1AT deficiency, and this screening may miss rarer cases, such as those caused by dysfunctional protein. We identified a patient with a previously unreported F/null phenotype that was missed by routine screening. This case highlights the wide variation in possible mutations, limitations in diagnostics, and the importance of combining clinical suspicion with measurement of protein levels, phenotypic analysis, and in appropriate cases expanded genetic analysis.

2011-01-01

72

Lung fibroblast alpha-smooth muscle actin expression and contractile phenotype in bleomycin-induced pulmonary fibrosis.  

PubMed Central

The emergence of the myofibroblast phenotype (characterized by alpha-smooth muscle actin expression) in wound healing and in tissues undergoing fibrosis is thought to be responsible for the increased contractility of the affected tissues. In bleomycin-induced pulmonary fibrosis, the myofibroblast is also responsible for the observed increase in collagen gene expression. To evaluate further these phenotypic changes in lung fibroblasts, contractile and other phenotypic properties of fibroblasts isolated from lungs of rats with bleomycin-induced fibrosis were compared with those of normal rats using in vitro models. Pulmonary fibrosis was induced in rats by endotracheal injection on day 0, and 7 and 14 days later the animals were sacrificed and lung fibroblasts isolated. Using immunofluorescence, < 10% of fibroblasts from control animals express alpha-smooth muscle actin when cultured as a monolayer. In contrast, 19% and 21% of cells from day 7 and day 14 bleomycin-treated animals, respectively, expressed this actin and with greater intensity than in control lung cells. This increase in actin expression was associated with enhanced contractility when evaluated using a three-dimensional cell culture model consisting of fibroblast-populated collagen gels. This enhanced contractility was abolished by treatment with antibody to transforming growth factor-beta (TGF-beta), whereas exogenous TGF-beta 1 and serum-stimulated contraction of control lung fibroblasts. TGF-beta 1 gene expression was greater in cells from bleomycin-treated animals than those from control lungs. These results show that cells with the myofibroblast phenotype are more abundant in fibrotic lung, and that these cells possess greater contractile capacity in vitro at least partly by virtue of their enhanced endogenous TGF-beta 1 gene expression. Images Figure 4 Figure 5 Figure 9

Zhang, H. Y.; Gharaee-Kermani, M.; Zhang, K.; Karmiol, S.; Phan, S. H.

1996-01-01

73

Treatment of a depressive disorder patient with EEG-driven photic stimulation  

Microsoft Academic Search

This study examined the effects of electroencephalographic-(EEG-) driven photic stimulation on a case of depressive disorder, as measured by a psychometric test of mood states, EEG parameters, and several autonomic indices. The EEG-driven photic stimulation enhances the alpha rhythm of brain waves using photic signals, the brightness of which is modulated by a subject's own alpha rhythm. The patient was

Hiroaki Kumano; Harumi Horie; Tomoko Shidara; Tomifusa Kuboki; Hiroyuki Suematsu; Mitsuo Yasushi

1996-01-01

74

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

75

PEG-IFN Alpha but Not Ribavirin Alters NK Cell Phenotype and Function in Patients with Chronic Hepatitis C  

PubMed Central

Background Ribavirin (RBV) remains part of several interferon-free treatment strategies even though its mechanisms of action are still not fully understood. One hypothesis is that RBV increases responsiveness to type I interferons. Pegylated Interferon alpha (PEG-IFNa) has recently been shown to alter natural killer (NK) cell function possibly contributing to control of hepatitis C virus (HCV) infection. However, the effects of ribavirin alone or in combination with IFNa on NK cells are unknown. Methods Extensive ex vivo phenotyping and functional analysis of NK cells from hepatitis C patients was performed during antiviral therapy. Patients were treated for 6 weeks with RBV monotherapy (n?=?11), placebo (n?=?13) or PEG-IFNa-2a alone (n?=?6) followed by PEG-IFNa/RBV combination therapy. The effects of RBV and PEG-IFNa-2a on NK cells were also studied in vitro after co-culture with K562 or Huh7.5 cells. Results Ribavirin monotherapy had no obvious effects on NK cell phenotype or function, neither ex vivo in patients nor in vitro. In contrast, PEG-IFNa-2a therapy was associated with an increase of CD56bright cells and distinct changes in expression profiles leading to an activated NK cell phenotype, increased functionality and decline of terminally differentiated NK cells. Ribavirin combination therapy reduced some of the IFN effects. An activated NK cell phenotype during therapy was inversely correlated with HCV viral load. Conclusions PEG-IFNa activates NK cells possibly contributing to virological responses independently of RBV. The role of NK cells during future IFN-free combination therapies including RBV remains to be determined.

Markova, Antoaneta A.; Mihm, Ulrike; Schlaphoff, Verena; Lunemann, Sebastian; Filmann, Natalie; Bremer, Birgit; Berg, Thomas; Sarrazin, Christoph; Zeuzem, Stefan; Manns, Michael P.; Cornberg, Markus; Herrmann, Eva; Wedemeyer, Heiner

2014-01-01

76

EEG spectrum as information carrier.  

PubMed

Spontaneous and provoked changes of vigilance and consciousness are determined by TCS (thalamocortical system) activity. This is relatively easy to monitor using EEG, which is a complex curve but open to analysis, e.g., by means of FFT (fast Fourier transformation). Twenty six persons (six normal controls, twelve epileptics, eight dements) had EEG recorded during rest, reaction to sound, and perception to simple tones or chords from Smetana's symphonic poem Vysehrad. The length of reaction time was found dependent on FFT changes: the longer the time, the higher are the delta and the lower the alpha activities in the EEG spectrum. However, with alpha increasing during relaxation, the reaction time grew longer regardless of whether delta had increased due to hyperventilation, sleep or subclinical epileptic discharges. During the perception of tones, FFT showed changes in the alpha and delta bands different from those during the perception of chords, and different again during relaxation, and that in both normal controls and epileptics. The demented persons revealed no discernible FFT differences in the perception of either tones or chords, the only differences were found in the resting sections of the spectrum. One and the same stimulus produced a stereotype FFT response, i.e., different stimuli elicited different FFT response in healthy and epileptic persons. The dements responded to identical stimuli differently, and had stereotype FFT response elicited by the same stimuli. The results suggest that FFT can represent the information content of the EEG curve and, indirectly, also that of micro-EEG as it reverberates between the thalamus and the cortex in the form of neuronal activity impulsations. This interneuronal impulsation coding is disordered in dements with atrophy of the cortex; it is marked, on the one hand, by increased variability in the perception of identical stimuli, and, on the other hand, by impaired differentiation, and, consequently, by increasingly stereotype responses to different stimuli. PMID:11221466

Faber, J; Srutová, L; Pilarová, M; Vucková, Z; Böhmová, D; Dobosová, L

1999-01-01

77

EEG alterations during treatment with olanzapine  

Microsoft Academic Search

The aim of this naturalistic observational study was to investigate EEG alterations in patients under olanzapine treatment\\u000a with a special regard to olanzapine dose and plasma concentration. Twenty-two in-patients of a psychiatric university ward\\u000a with the monodiagnosis of paranoid schizophrenia (ICD-10: F20.0), who received a monotherapy of olanzapine were included in\\u000a this study. All patients had a normal alpha-EEG before

Detlef DegnerMichael; Michael A. Nitsche; Frank Bias; Eckart Rüther; Udo Reulbach

78

Intravenous administration of alpha-1-proteinase inhibitor in patients of PiZ and PiM phenotype. Preliminary report  

SciTech Connect

Nine patients with moderate pulmonary emphysema, six of PiZ phenotype and three of PiM phenotype, have received a single intravenous infusion of alpha-1-proteinase inhibitor (human) (A1PI), in a dose of 60 mg/kg over a 30-minute period. They also received a tracer dose (300 microCi) of /sup 131/I-labeled A1PI. No active or passive immunization against hepatitis was given. No acute toxicity was observed. Compared with baseline data, significant elevations of serum A1PI (measured both antigenically and as anti-elastase activity) occurred, with a serum half-life approximating 110 hours. Bronchoalveolar lavage fluid, obtained 48 hours after infusion, reflected a significant increase in A1PI concentration versus baseline bronchoalveolar lavage fluid values. Serial gamma camera images of the lungs confirmed persistence of enhanced lung radioactivity for several days. Urinary desmosine excretion did not change following A1PI infusion. During the period of follow-up thus far, no patient has had chronic toxicity, results of liver function tests have been stable, and there has been no development of hepatitis B antigen or antibodies to hepatitis B surface or core antigens.

Moser, K.M.; Smith, R.M.; Spragg, R.G.; Tisi, G.M.

1988-06-24

79

Studying spontaneous EEG activity with fMRI  

Microsoft Academic Search

The multifaceted technological challenge of acquiring simultaneous EEG-correlated fMRI data has now been met and the potential exists for mapping electrophysiological activity with unprecedented spatio-temporal resolution. Work has already begun on studying a host of spontaneous EEG phenomena ranging from alpha rhythm and sleep patterns to epileptiform discharges and seizures, with far reaching clinical implications. However, the transformation of EEG

A. Salek-Haddadi; K. J. Friston; L. Lemieux; D. R. Fish

2003-01-01

80

Changes in the spectral power and coherence of the EEG alpha rhythm in humans performing grasp efforts by the right and left arm  

Microsoft Academic Search

We compared changes in the EEG indices in healthy dextral volunteers performing static force grasps by the arm. Three test\\u000a modes were used: (i) performance of two successive grasps by the dominant (right) arm (test A), (ii) performance of two successive\\u000a grasps by the subdominant (left) arm (test B), and (iii) performance of the grasps first by the right arm

E. P. Man’kovskaya

2006-01-01

81

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.

2014-01-01

82

Association of tumour necrosis factor alpha variants with the CF pulmonary phenotype  

PubMed Central

Background: The pulmonary phenotype in patients with cystic fibrosis (CF), even in those with the same CF transmembrane conductance regulator (CFTR) genotype, is variable and must therefore be influenced by secondary genetic factors as well as environmental factors. Possible candidate genes that modulate the CF lung phenotype may include proinflammatory cytokines. One such protein is tumour necrosis factor ? (TNF?), a member of the immune system. Methods: Three polymorphic loci in the promoter (–851c/t, –308g/a, –238g/a) and one polymorphic locus in intron 1 (+691g ins/del) of the TNF? gene were typed by a single nucleotide primer extension assay in CF patients and healthy controls. Spirometric data and first age of infection with Pseudomonas aeruginosa were collected retrospectively from patients' medical records. Results: An association was found between the TNF? +691g ins/del polymorphic locus and severity of CF lung disease. Patients heterozygous for +691g ins and +691g del were more likely to have better pulmonary function (mean (SD) forced expiratory volume in 1 second (FEV1) 79.7 (12.8)% predicted) than patients homozygous for +691g ins (mean (SD) FEV1 67.5 (23.0)% predicted; p = 0.008, mean difference 12.2%, 95% CI 3.5 to 21.0). Also, patients heterozygous for +691g ins and +691g del were more likely to have an older first age of infection with P aeruginosa (mean (SD) 11.4 (6.0) years) than patients homozygous for +691g ins (mean (SD) 8.3 (4.6) years; p = 0.018, mean difference 3.1 years, 95% CI 0.5 to 5.6). An association was also found with the –851c/t polymorphic locus. In the group of patients with more severe FEV1% predicted, a higher proportion of patients were homozygous for the –851c allele than in the other group of patients (p = 0.04, likelihood ratio ?2, odds ratio = 2.4). Conlusion: TNF? polymorphisms are associated with the severity of CF lung disease in Czech and Belgian patients with CF.

Yarden, J; Radojkovic, D; De Boeck, K; Macek, M; Zemkova, D; Vavrova, V; Vlietinck, R; Cassiman, J; Cuppens, H

2005-01-01

83

Topographic brain mapping of EEG after ergotalkaloids in elderlies  

Microsoft Academic Search

Previous investigations have demonstrated that ergotalkaloids produce oppositional EEG changes to (pathological) aging i.e. decrease of delta\\/theta and increase of alpha or alphaadjacent activity indicating increased vigilance (Saletu and Grfinberger, 1985). As these drug related changes are rather subtle and essential changes may only be detected by multilead analysis, topographic brain mapping of the EEG has been used in the

B. Saletu; P. Anderer; J. Griinberger; M. Frey; D. H. Meier

1989-01-01

84

The Utility of EEG Band Power Analysis in the Study of Infancy and Early Childhood  

Microsoft Academic Search

Research employing electroencephalographic (EEG) techniques with infants and young children has flourished in recent years due to increased interest in understanding the neural processes involved in early social and cognitive development. This review focuses on the functional characteristics of the alpha, theta, and gamma frequency bands in the developing EEG. Examples of how analyses of EEG band power have been

Joni N. Saby; Peter J. Marshall

2012-01-01

85

The Effects of Mobile Phone Usage on Human Brainwave Using EEG  

Microsoft Academic Search

The aim of this research is to investigate any effects of mobile phone usage on human brainwaves using electroencephalograph (EEG) particularly on alpha wave. EEG signals were recorded from thirty samples that make calls from a mobile phone to another party without conversation. The mobile phone is strapped to the right ear. The EEG recording took place before, during and

Zunairah Hj Murat; Ros Shilawani S. AbdulKadir; Roshakimah Mohd Isa; Mohd Nasir Taib

2011-01-01

86

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.

Kraus, Teresa; Cherry, Mohamad

2014-01-01

87

[Phenotypic manifestation and trans-conversion of primary genetic material damages considered in the alpha-test on the yeast Saccharomyces cerevisiae].  

PubMed

Primary (spontaneous and externally induces) damages to genetic material frequently lead to heritable changes (gene mutations, chromosome aberrations and nondisjunction), which may cause cancer inherent and inborn diseases. It is suggested that primary damages may affect a phenotype until they are repaired or become mutations during inaccurate repair The alpha-test on the yeast Saccharomyces cerevisiae can answer the fundamental questions as the nature of primary damages that can be phenotypically manifested, their occurrence, conversion to each other and repair or conversion to heritable changes in genetic material. PMID:22250397

Stepchenkova, E I; Kochenova, O V; Zhuk, A S; Andre?chuk, Iu V; Inge-Vechtomov, S G

2011-01-01

88

Restoration of growth phenotypes of Escherichia coli DH5alpha in minimal media through reversal of a point mutation in purB.  

PubMed

A point mutation (E115K) resulting in slower growth of Escherichia coli DH5alpha and XL1-Blue in minimal media was identified in the purB gene, coding for adenylosuccinate lyase (ASL), through complementation with an E. coli K-12 genomic library and serial subcultures. Chromosomal modification reversing the mutation to the wild type restored growth phenotypes in minimal media. PMID:20675450

Jung, Suk-Chae; Smith, Chris L; Lee, Ki-Sung; Hong, Min-Eui; Kweon, Dae-Hyuk; Stephanopoulos, Gregory; Jin, Yong-Su

2010-09-01

89

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

90

Quantitative EEG analysis in post-traumatic anosmia.  

PubMed

Many objective and quantitative methods have been developed to create a procedure or a device to prove, describe and quantify olfactory deficit and anosmia, especially after a head trauma. Electrophysiological testing throughout olfactoelectroencephalography (olfactoEEG) is based on brain activity desynchronisation, and on the subsequent disappearance of alpha activity on the posterior regions after an olfactory stimulus. Yet traditional evaluation of EEG can be difficult, because of little or hardly detectable alpha activity on the posterior regions ('alpha rare'). The aim of this study was to evaluate the Olfactory Stop Reaction (OSR) by means of frequency band power calculation and subsequent topographical mapping in patients with post-traumatic anosmia, who presented 'alpha rare' EEG. Twenty-five consecutive patients, affected by anosmia caused by head trauma, were submitted to an EEG recording with olfactory stimulation. After signal processing and analysis, an Olfactory Stop Reaction was detected in 17 out of 25 patients; moreover, in these patients we detected a significant decrease in alpha band power in the occipital regions and an increase in theta band power on midline frontal and central regions after olfactory stimulation. In the remaining eight patients, no significant variation in band power was observed. In conclusion, an objective evaluation of the olfactory function with this method of automatic EEG signal analysis allows the limits given by psychophysical methods and traditional EEG to be overcome and attempts to fulfil the requirements for standardization of olfactory function evalution. PMID:17113930

Bonanni, E; Borghetti, D; Fabbrini, M; Maestri, M; Cignoni, F; Sartucci, F; Murri, L

2006-12-11

91

Normal "suspicious" EEG.  

PubMed

The EEG is a unique measure of electrical brain function and is widely used in patients with seizures. Many normal variants and variations of normal EEG have a predilection for the temporal lobe and mimic epileptiform discharges. The high prevalence of temporal lobe epilepsy and the propensity for normal variants to occupy the temporal lobe may result in an undesired bias, leading to misidentification of normal waveforms. Learning the common pitfalls, such as the variations of normal EEG, benign variants, and common artifacts, are essential lessons in EEG. Continuing education and acquiring experience in EEG interpretation are the basic tools to ensure patient safety. Above all, judging the results of the EEG interpretation in light of the patient's clinical symptoms is a prerequisite to ensure proper management. PMID:23267043

Tatum, William O

2013-01-01

92

The preliminary study on the effect of nasyid music and rock music on brainwave signal using EEG  

Microsoft Academic Search

This preliminary study analyzes the effect of nasyid music and rock music on brainwave signal particularly focusing on alpha wave. EEG data were recorded from 30 students from Faculty of Electrical Engineering, UiTM age 18 to 27 years old. Students were interviewed before EEG recording to find out their music preference. Using EEG, the brainwave signal of the sample is

Ros Shilawani S. Abdul Kadir; Mohd Hafizi Ghazali; Zunairah Hj. Murat; Mohd Nasir Taib; Husna Abdul Rahman; Siti Armiza Mohd Aris

2010-01-01

93

The Utility of EEG Band Power Analysis in the Study of Infancy and Early Childhood  

PubMed Central

Research employing electroencephalographic (EEG) techniques with infants and young children has flourished in recent years due to increased interest in understanding the neural processes involved in early social and cognitive development. This review focuses on the functional characteristics of the alpha, theta, and gamma frequency bands in the developing EEG. Examples of how analyses of EEG band power have been applied to specific lines of developmental research are also discussed. These examples include recent work on the infant mu rhythm and action processing, frontal alpha asymmetry and approach-withdrawal tendencies, and EEG power measures in the study of early psychosocial adversity.

Saby, Joni N.; Marshall, Peter J.

2012-01-01

94

Single Channel Wireless EEG: Proposed Application in Train Drivers  

Microsoft Academic Search

Electroencephalography (EEG) can be used as an indicator of fatigue. Several studies have shown that slow wave brain activities, delta (0-4 Hz) and theta (4-8 Hz), increase as an individual becomes fatigued, while the fast brain activities, alpha (8-13 Hz) and beta (13-35 Hz), decrease. However, an EEG is a complex piece of equipment that is generally used in laboratory

Surya Darma Ridwan; Robert Thompson; Budi Thomas Jap; Sara Lal; Peter Fischer

2008-01-01

95

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

96

A better oscillation detection method robustly extracts EEG rhythms across brain state changes: the human alpha rhythm as a test case.  

PubMed

Oscillatory activity is a principal mode of operation in the brain. Despite an intense resurgence of interest in the mechanisms and functions of brain rhythms, methods for the detection and analysis of oscillatory activity in neurophysiological recordings are still highly variable across studies. We recently proposed a method for detecting oscillatory activity from time series data, which we call the BOSC (Better OSCillation detection) method. This method produces systematic, objective, and consistent results across frequencies, brain regions and tasks. It does so by modeling the functional form of the background spectrum by fitting the empirically observed spectrum at the recording site. This minimizes bias in oscillation detection across frequency, region and task. Here we show that the method is also robust to dramatic changes in state that are known to influence the shape of the power spectrum, namely, the presence versus absence of the alpha rhythm, and can be applied to independent components, which are thought to reflect underlying sources, in addition to individual raw signals. This suggests that the BOSC method is an effective tool for measuring changes in rhythmic activity in the more common research scenario wherein state is unknown. PMID:20807577

Whitten, Tara A; Hughes, Adam M; Dickson, Clayton T; Caplan, Jeremy B

2011-01-15

97

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

98

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.

Brown, Timothy; Johnson, Robin; Milavetz, Gary

2013-01-01

99

Widespread EEG Changes Precede Focal Seizures  

PubMed Central

The process by which the brain transitions into an epileptic seizure is unknown. In this study, we investigated whether the transition to seizure is associated with changes in brain dynamics detectable in the wideband EEG, and whether differences exist across underlying pathologies. Depth electrode ictal EEG recordings from 40 consecutive patients with pharmacoresistant lesional focal epilepsy were low-pass filtered at 500 Hz and sampled at 2,000 Hz. Predefined EEG sections were selected immediately before (immediate preictal), and 30 seconds before the earliest EEG sign suggestive of seizure activity (baseline). Spectral analysis, visual inspection and discrete wavelet transform were used to detect standard (delta, theta, alpha, beta and gamma) and high-frequency bands (ripples and fast ripples). At the group level, each EEG frequency band activity increased significantly from baseline to the immediate preictal section, mostly in a progressive manner and independently of any modification in the state of vigilance. Preictal increases in each frequency band activity were widespread, being observed in the seizure-onset zone and lesional tissue, as well as in remote regions. These changes occurred in all the investigated pathologies (mesial temporal atrophy/sclerosis, local/regional cortical atrophy, and malformations of cortical development), but were more pronounced in mesial temporal atrophy/sclerosis. Our findings indicate that a brain state change with distinctive features, in the form of unidirectional changes across the entire EEG bandwidth, occurs immediately prior to seizure onset. We postulate that these changes might reflect a facilitating state of the brain which enables a susceptible region to generate seizures.

Perucca, Piero; Dubeau, Francois; Gotman, Jean

2013-01-01

100

Electroencephalogram (EEG) (For Parents)  

MedlinePLUS

... problems such as sleep disorders and changes in behavior. EEGs are sometimes used to evaluate brain activity after a severe head injury or before heart or liver transplantation. Preparation If ...

101

EEG-Based \\  

Microsoft Academic Search

Recently, EEG-based technology has become more popular in “serious” games designs and developments since new wireless headsets that meet consumer demand for wear ability, price, portability and ease-of-use are coming to the market. Originally, EEG-based technologies were used in neurofeedback games and brain-computer interfaces. Now, such technologies could be used in entertainment, e-learning and new medical applications. In this paper,

Qiang Wang; Olga Sourina; Minh Khoa Nguyen

2010-01-01

102

Computer analysis of EEG activity in dementia of the Alzheimer's type and Huntington's disease.  

PubMed

Computer analysis of the EEG was obtained in the course of evaluation of 35 patients with Dementia of the Alzheimer's Type (DAT) and Huntington's disease (HD), and compared to 20 age-matched normal controls. On-line computer analysis of the EEG consisted of: 1) compressed spectral array (CSA) displays (2-6 channels); 2) relative frequency power (4 bands) and 3) an averaged frequency power function [( alpha/alpha + theta power (microV 2)] X 100 = % EEG Power function). Frequency power reflected increased theta, and reduced alpha components, in patient groups. Significant correlation was obtained between % EEG Power function, and clinical stage of dementia. This function correctly identified 17/25 DAT, and 7/10 HD patients, and gave additional quantification to the primary EEG. PMID:2139184

Streletz, L J; Reyes, P F; Zalewska, M; Katz, L; Fariello, R G

1990-01-01

103

Initial investigation of brainwave synchronization after five sessions of Horizontal Rotation intervention using EEG  

Microsoft Academic Search

This research investigates the effects of five sessions of Horizontal Rotation (HR) on human brainwaves synchronization using EEG. EEG signals were captured from 42 participants before and after undergoing HR using two-channel bipolar connection in a controlled environment. The signals were filtered and classified into the four frequency bands; Delta, Theta, Alpha and Beta. Graphs were plotted and paired T-test

Z. H. Murat; M. N. Taib; Z. M. Hanafiah; S. Lias; R. S. S. A. Kadir; H. A. Rahman

2009-01-01

104

Evaluation of an adaptive automation system using three EEG indices with a visual tracking task  

Microsoft Academic Search

A system was evaluated for use in adaptive automation using two experiments with electroencephalogram (EEG) indices based on the beta, alpha, and theta bandwidths. Subjects performed a compensatory tracking task while their EEG was recorded and converted to one of three engagement indices: ?\\/(?+?), ?\\/?, or 1\\/?. In experiment one, the tracking task was switched between manual and automatic modes

Frederick G Freeman; Peter J Mikulka; Lawrence J Prinzel; Mark W Scerbo

1999-01-01

105

Quantitative EEG Markers in Mild Cognitive Impairment: Degenerative versus Vascular Brain Impairment  

PubMed Central

We evaluated the relationship between brain rhythmicity and both the cerebrovascular damage (CVD) and amygdalohippocampal complex (AHC) atrophy, as revealed by scalp electroencephalography (EEG) in a cohort of subjects with mild cognitive impairment (MCI). All MCI subjects underwent EEG recording and magnetic resonance imaging. EEGs were recorded at rest. Relative power was separately computed for delta, theta, alpha1, alpha2, and alpha3 frequency bands. In the spectral band power the severity of CVD was associated with increased delta power and decreased alpha2 power. No association of vascular damage was observed with alpha3 power. Moreover, the theta/alpha1 ratio could be a reliable index for the estimation of the individual extent of CV damage. On the other side, the group with moderate hippocampal atrophy showed the highest increase of alpha2 and alpha3 power. Moreover, when the amygdalar and hippocampal volumes are separately considered, within amygdalohippocampal complex (AHC), the increase of theta/gamma ratio is best associated with amygdalar atrophy whereas alpha3/alpha2 ratio is best associated with hippocampal atrophy. CVD and AHC damages are associated with specific EEG markers. So far, these EEG markers could have a prospective value in differential diagnosis between vascular and degenerative MCI.

Moretti, D. V.; Zanetti, O.; Binetti, G.; Frisoni, G. B.

2012-01-01

106

[EEG changes with unblocking of acoustic and visual sensory canals].  

PubMed

Modally specific and supramodal components of EEG dynamics, related to involuntary reorientation of anticipatory attention from internal into external, were studied using unblocking of either visual or acoustic apparatus. EEG registration took place while the examinees were in the resting states: with opened eyes; with closed eyes; with closed eyes and inserted noise-protective earplugs. Averaged values of EEG power in each of the derivations and of EEG coherence in each of the derivation pairs were calculated for an every examinee and for each of the states. The estimations were done in delta, theta, alphal, alpha2, beta1, beta2, gamma frequency bands. The received results support an idea about manifestation of both supramodal and modally specific components in brain mechanisms of involuntary anticipatory attention. These results seem to be of certain interest for existing discussion on divergence and convergence between systemic mechanisms of visual and auditory attention. PMID:21542328

Bo?tsova, Iu A; Dan'ko, S G

2011-01-01

107

Does EEG Montage Influence Alzheimer's Disease Electroclinic Diagnosis?  

PubMed Central

There is not a specific Alzheimer's disease (AD) diagnostic test. AD diagnosis relies on clinical history, neuropsychological, and laboratory tests, neuroimaging and electroencephalography. Therefore, new approaches are necessary to enable earlier and more accurate diagnosis and to measure treatment results. Quantitative EEG (qEEG) can be used as a diagnostic tool in selected cases. The aim of this study was to answer if distinct electrode montages have different sensitivity when differentiating controls from AD patients. We analyzed EEG spectral peaks (delta, theta, alpha, beta, and gamma bands), and we compared references (Biauricular, Longitudinal bipolar, Crossed bipolar, Counterpart bipolar, and Cz reference). Support Vector Machines and Logistic Regression classifiers showed Counterpart bipolar montage as the most sensitive electrode combination. Our results suggest that Counterpart bipolar montage is the best choice to study EEG spectral peaks of controls versus AD.

Trambaiolli, L. R.; Lorena, A. C.; Fraga, F. J.; Kanda, P. A. M. K.; Nitrini, R.; Anghinah, R.

2011-01-01

108

Does EEG montage influence Alzheimer's disease electroclinic diagnosis?  

PubMed

There is not a specific Alzheimer's disease (AD) diagnostic test. AD diagnosis relies on clinical history, neuropsychological, and laboratory tests, neuroimaging and electroencephalography. Therefore, new approaches are necessary to enable earlier and more accurate diagnosis and to measure treatment results. Quantitative EEG (qEEG) can be used as a diagnostic tool in selected cases. The aim of this study was to answer if distinct electrode montages have different sensitivity when differentiating controls from AD patients. We analyzed EEG spectral peaks (delta, theta, alpha, beta, and gamma bands), and we compared references (Biauricular, Longitudinal bipolar, Crossed bipolar, Counterpart bipolar, and Cz reference). Support Vector Machines and Logistic Regression classifiers showed Counterpart bipolar montage as the most sensitive electrode combination. Our results suggest that Counterpart bipolar montage is the best choice to study EEG spectral peaks of controls versus AD. PMID:21629711

Trambaiolli, L R; Lorena, A C; Fraga, F J; Kanda, P A M K; Nitrini, R; Anghinah, R

2011-01-01

109

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.

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

2012-01-01

110

Telemetered EEG in schizophrenia: spectral analysis during abnormal behaviour episodes.  

PubMed Central

In an attempt to detect electroencephalographic (EEG) changes associated with characteristic clinical signs and symptoms of schizophrenia, power spectra were derived from scalp EEGs of schizophrenic patients recorded by telemetry during free behaviour on their psychiatric wards. Power spectra from EEG epochs coincident with psychomotor blocking, stereotyped automatism or hallucinations were compared with spectra derived during periods of relatively normal behaviour, during performance of specific tasks and spectra from control subjects. Ramp spectra, characterised by a smooth decline in power from lowest to highest frequencies, previously found in conjunction with subcortical spike activity of epilepsy were not found in any control subject, but appeared in spectra from schizophrenic patients during catatonic episodes, hallucinatory periods and visual checking. Schizophrenic patients also had more slow activity and less alpha activity in their EEGs than normal control subjects. Images

Stevens, J R; Livermore, A

1982-01-01

111

Tumor necrosis factor-alpha promoter variants and iron phenotypes in 785 Hemochromatosis and Iron Overload Screening (HEIRS) Study participants  

PubMed Central

We sought to determine if TNF promoter variants could explain iron phenotype heterogeneity in adults with previous HFE genotyping. HEIRS Study participants genotyped for C282Y and H63D were designated as high transferrin saturation (TS) and/or serum ferritin (SF) (high TS/SF), low TS/SF, or controls. We grouped 191 C282Y homozygotes as high TS/SF, low TS/SF, or controls, and 594 other participants by race/ethnicity as high TS/SF or controls. Using denaturing high-performance liquid chromatography (DHPLC), we screened the TNF promoter region in each participant. We performed multiple regression analyses in C282Y homozygotes using age, sex, HEIRS Study Field Center, and positivity for TNF ?308G?A and ?238G?A to determine if these attributes predicted ln TS or ln SF. DHPLC analyses were successful in 99.3% of 791 participants and detected 9 different variants; TNF ?308G?A and ?238G?A were the most prevalent. Most subjects positive for variants were heterozygous. The phenotype frequencies of each variant did not differ significantly (p <0.05) across subgroups of C282Y homozygotes, or across white, black, Hispanic, and Asian non-C282Y homozygotes subgrouped as high TS/SF phenotypes and controls. TNF ?308G?A positivity was a significant predictor of initial screening ln TS but not ln SF; TNF ?238G?A predicted neither ln TS nor ln SF. We conclude that TNF promoter variants have little, if any, effect on initial screening SF values in adults with or without C282Y homozygosity. We cannot exclude a possible association of homozygosity for TNF promoter variants on TS and SF values.

Acton, Ronald T.; Barton, James C.; Leiendecker-Foster, Catherine; Zaun, Christopher; McLaren, Christine E.; Eckfeldt, John H.

2013-01-01

112

The combination of exercise training and alpha-lipoic acid treatment has therapeutic effects on the pathogenic phenotypes of Alzheimer's disease in NSE/APPsw-transgenic mice.  

PubMed

Exercise training was suggested as a practical therapeutic strategy for human subjects suffering from Alzheimer's disease (AD) in our previous study. Therefore, the purpose of this study was to investigate the effects of combining exercise training with the administration of antioxidants on the pathological phenotype of AD. To accomplish this, non-transgenic mice (Non-Tg) and NSE/APPsw Tg mice were treated with alpha-lipoic acid and treadmill exercised for 16 weeks, after which their brains were evaluated to determine whether any changes in the pathological phenotype-related factors occurred. The results indicated that (i) the combination-applied (COMA) Tg group with exercise training (ET) and alpha-lipoic acid administration (LA) showed ameliorated spatial learning and memory compared to the sedentary (SED)-Tg and single-treatment groups; (ii) there were no differences in the level of Abeta-42 peptides across groups; (iii) the level of glucose transporter-1 and brain-derived neurotrophic factor proteins were highly increased in the COMA group, (iv) ET and LA did not induce a synergistic effect on the expression of heat shock protein-70 and apoptotic proteins including Bax and caspase-3; (v) the levels of SOD-1 and CAT suppressing oxidative stress were extensively higher in the COMA than in the single-treated groups and (vi) there were no significant differences across groups regarding these serum characteristics, although these levels were lower than the SED-Tg group. Taken together, these results suggest that the combination with ET and LA may contribute to protect the neuron injury induced by Abeta peptides and may be considered an effective therapeutic strategy for human subjects suffering from AD. PMID:20127037

Cho, Joon Y; Um, Hyun S; Kang, Eun B; Cho, In H; Kim, Chul H; Cho, Jung S; Hwang, Dae Y

2010-03-01

113

Contrasting skeletal phenotypes in mice with an identical mutation targeted to thyroid hormone receptor alpha1 or beta.  

PubMed

Thyroid hormone (T(3)) regulates bone turnover and mineralization in adults and is essential for skeletal development. Surprisingly, we identified a phenotype of skeletal thyrotoxicosis in T(3) receptor beta(PV) (TRbeta(PV)) mice in which a targeted frameshift mutation in TRbeta results in resistance to thyroid hormone. To characterize mechanisms underlying thyroid hormone action in bone, we analyzed skeletal development in TRalpha1(PV) mice in which the same PV mutation was targeted to TRalpha1. In contrast to TRbeta(PV) mice, TRalpha1(PV) mutants exhibited skeletal hypothyroidism with delayed endochondral and intramembranous ossification, severe postnatal growth retardation, diminished trabecular bone mineralization, reduced cortical bone deposition, and delayed closure of the skull sutures. Skeletal hypothyroidism in TRalpha1(PV) mutants was accompanied by impaired GH receptor and IGF-I receptor expression and signaling in the growth plate, whereas GH receptor and IGF-I receptor expression and signaling were increased in TRbeta(PV) mice. These data indicate that GH receptor and IGF-I receptor are physiological targets for T(3) action in bone in vivo. The divergent phenotypes observed in TRalpha1(PV) and TRbeta(PV) mice arise because the pituitary gland is a TRbeta-responsive tissue, whereas bone is TRalpha responsive. These studies provide a new understanding of the complex relationship between central and peripheral thyroid status. PMID:16051666

O'Shea, Patrick J; Bassett, J H Duncan; Sriskantharajah, Srividya; Ying, Hao; Cheng, Sheue-yann; Williams, Graham R

2005-12-01

114

Spatial localization of EEG electrodes  

Microsoft Academic Search

Aim of the studyAn important goal for EEG-based functional brain studies is to estimate the location of brain sources that produce the scalp-recorded signals. Such source localization requires locating precisely the position of the EEG sensors. This review describes and compares different methods that are used for localizing EEG sensors.

L. Koessler; L. Maillard; A. Benhadid; J.-P. Vignal; M. Braun; H. Vespignani

2007-01-01

115

Cortical dynamics of human scalp EEG origins in a visually guided motor execution.  

PubMed

The EEG mu rhythm is often used as an index of activation in the sensorimotor cortex. However, the blur caused by volume conduction makes it difficult to identify the exact origin of the EEG rhythm in the brain using only the human scalp EEG. In this study, simultaneous fMRI and EEG measurements were performed during a visually guided motor execution task in order to investigate whether the mu rhythm in the scalp EEG is an indication of the activity in the sensorimotor cortex. In addition, a new method was proposed for reconstruction of the cortical EEG activity through the fusion of fMRI and EEG data. A suppression of mu rhythm appeared around the lateral central electrode sites, just above the sensorimotor cortex, in association with the activity in that region. During a visually guided motor execution task, the alpha rhythms at the occipital electrode sites and the alpha rhythm at the central electrode sites also showed a correlation with the fMRI signal in the occipital and the supplementary motor cortices, respectively. This method allows the investigation of the scalp EEG origin with the spatial precision of fMRI, while retaining dynamic properties of the cortex with the temporal precision of EEG. PMID:22659479

Mizuhara, Hiroaki

2012-09-01

116

EEG-fMRI  

PubMed Central

Objective: In patients with nonlesional frontal lobe epilepsy (FLE), the delineation of the epileptogenic zone is difficult. Therefore these patients are often not considered for surgery due to an unclear seizure focus. The aim of this study was to investigate whether EEG-fMRI can add useful information in the preoperative evaluation of these patients. Methods: Nine nonlesional FLE patients were studied with EEG-fMRI using a 3 T scanner. Spike-related blood oxygen level dependent (BOLD) signal changes were compared to the topography of the spikes and to PET and SPECT results if available. The structural MRIs were reviewed for subtle abnormalities in areas that showed BOLD responses. For operated patients, postoperative resection and histology were compared to BOLD responses. Results: Concordance between spike localization and positive BOLD response was found in 8 patients. PET and SPECT investigations corresponded with BOLD signal changes in 6 of 7 investigations. In 2 cases, reviewing the structural MRI guided by EEG-fMRI data resulted in considering a suspicious deep sulcus. Two patients were operated. In 1, the resected cortex corresponded with the suspicious sulcus and fMRI results and histology showed cortical dysplasia. In another, histology revealed an extended microdysgenesis not visible on structural MRI. EEG-fMRI had shown activation just adjacent to the resected pathologic area. Conclusions: Our study provides different types of support (topography, concordance with PET and SPECT, structural peculiarities, postoperative histology) that EEG-fMRI may help to delineate the epileptic focus in patients with nonlesional frontal lobe epilepsy, a challenging group in the preoperative evaluation. GLOSSARY BOLD = blood oxygen level dependent; FLE = frontal lobe epilepsy; fMRI = functional MRI; HFR = hemodynamic response function; IED = interictal epileptiform discharges; TE = echo time; TR = repetition time.

Moeller, F; Tyvaert, L; Nguyen, D K.; LeVan, P; Bouthillier, A; Kobayashi, E; Tampieri, D; Dubeau, F; Gotman, J

2009-01-01

117

Specific EEG Changes Associated with Atrophy of Hippocampus in Subjects with Mild Cognitive Impairment and Alzheimer's Disease  

PubMed Central

We evaluated the association between hippocampal atrophy and increase of the EEG markers alpha3/alpha2 relative power ratio in mild cognitive impairment (MCI) and Alzheimer's disease patients. Seventy-nine subjects with MCI and 11 patients with AD underwent EEG recording and MRI scan. The MCI group was subdivided in three subgroups according to growing hippocampal atrophy. The groups were characterized by alpha3/alpha2 relative power ratio. In AD patients group mapped hippocampal regions were computed and related with alpha3/alpha2 power ratio. Results show that the increase of alpha3/alpha2 power ratio is correlated with atrophy of hippocampus both in MCI and in Alzheimer's disease patients. This finding confirms the possible diagnostic role of EEG markers as diagnostic and prognostic factors in patient with prodromal and declared Alzheimer's disease.

Moretti, D. V.; Prestia, A.; Fracassi, C.; Binetti, G.; Zanetti, O.; Frisoni, G. B.

2012-01-01

118

A specific microdomain ("glycosynapse 3") controls phenotypic conversion and reversion of bladder cancer cells through GM3-mediated interaction of alpha3beta1 integrin with CD9.  

PubMed

Cell motility is highly dependent on the organization and function of microdomains composed of integrin, proteolipid/tetraspanin CD9, and ganglioside (Ono, M., Handa, K., Sonnino, S., Withers, D. A., Nagai, H., and Hakomori, S. (2001) Biochemistry 40, 6414-6421; Kawakami, Y., Kawakami, K., Steelant, W. F. A., Ono, M., Baek, R. C., Handa, K., Withers, D. A., and Hakomori, S. (2002) J. Biol. Chem. 277, 34349-34358), later termed "glycosynapse 3" (Hakomori, S., and Handa, K. (2002) FEBS Lett. 531, 88-92, 2002). Human bladder cancer cell lines KK47 (noninvasive and nonmetastatic) and YTS1 (highly invasive and metastatic), both derived from transitional bladder epithelia, are very similar in terms of integrin composition and levels of tetraspanin CD9. Tetraspanin CD82 is absent in both. The major difference is in the level of ganglioside GM3, which is several times higher in KK47 than in YTS1. We now report that the GM3 level reflects glycosynapse function as follows: (i) a stronger interaction of integrin alpha3 with CD9 in KK47 than in YTS1; (ii) conversion of benign, low motility KK47 to invasive, high motility cells by depletion of GM3 by P4 (D-threo-1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol) treatment or by knockdown of CD9 by the RNA interference method; (iii) reversion of high motility YTS1 to low motility phenotype like that of KK47 by exogenous GM3 addition, whereby the alpha3-to-CD9 interaction was enhanced; (iv) low GM3 level activated c-Src in YTS1 or in P4-treated KK47, and high GM3 level by exogenous addition caused Csk translocation into glycosynapse, with subsequent inhibition of c-Src activation; (v) inhibition of c-Src by "PP2" in YTS1 greatly reduced cell motility. Thus, GM3 in glycosynapse 3 plays a dual role in defining glycosynapse 3 function. One is by modulating the interaction of alpha3 with CD9; the other is by activating or inhibiting the c-Src activity, possibly through Csk translocation. High GM3 level decreases tumor cell motility/invasiveness, whereas low GM3 level enhances tumor cell motility/invasiveness. Oncogenic transformation and its reversion can be explained through the difference in glycosynapse organization. PMID:16103120

Mitsuzuka, Koji; Handa, Kazuko; Satoh, Makoto; Arai, Yoichi; Hakomori, Senitiroh

2005-10-21

119

Low levels of tumor necrosis factor alpha increase tumor growth by inducing an endothelial phenotype of monocytes recruited to the tumor site.  

PubMed

Microenvironmental cues instruct infiltrating tumor-associated myeloid cells to drive malignant progression. A subpopulation of tumor-associated myeloid cells coexpressing endothelial and myeloid markers, although rare in peripheral blood, are primarily associated with tumors where they enhance tumor growth and angiogenesis. These biphenotypic vascular leukocytes result from the endothelial differentiation of myeloid progenitors, a process regulated by tumor necrosis factor (TNF)alpha in vitro. An in vivo increase in tumor-derived TNFalpha expression promoted tumor growth and vascularity of mouse melanoma, lung cancer, and mammary tumors. Notably, tumor growth was accompanied by a significant increase in myeloid/endothelial biphenotypic populations. TNFalpha-associated tumor growth, vascularity, and generation of tumor vascular leukocytes in mouse melanoma tumors were dependent on intact host TNFalpha receptors. Importantly, TNFalpha-expressing tumors did not exhibit increased inflammation over control tumors, suggesting a unique action related to myeloid to endothelial differentiation. Our studies suggest that TNFalpha constitutes a tumor microenvironment signal that biases recruited monocytes toward a proangiogenic/provasculogenic myeloid/endothelial phenotype. PMID:19118019

Li, Bin; Vincent, Alicia; Cates, Justin; Brantley-Sieders, Dana M; Polk, D Brent; Young, Pampee P

2009-01-01

120

Two novel functional mutations in the Na+,K+-ATPase alpha2-subunit ATP1A2 gene in patients with familial hemiplegic migraine and associated neurological phenotypes.  

PubMed

Mutations in the ATP1A2 gene, encoding the alpha2-subunit of the Na+,K+-ATPase, are associated with familial hemiplegic migraine type 2. The majority of ATP1A2 mutations were reported in patients with hemiplegic migraine without any additional neurological findings. Here, we report on two novel ATP1A2 mutations that were identified in two Portuguese probands with hemiplegic migraine and interesting additional clinical features. The proband's of family 1 (with a V362E mutation) had mood alterations, classified as a borderline personality. The proband in family 2 (with a P796S mutation) had mild mental impairment, in addition to hemiplegic migraine; more severe mental retardation was observed in his brother, who also had hemiplegic migraine and carried the same mutation. Cell-survival assays clearly showed abnormal functioning of mutant Na+,K+-ATPase, indicating that both ATP1A2 mutants are disease causing. Additionally, our results suggest a possible causal relationship of the ATP1A2 mutations with the complex clinical phenotypes observed in the probands. PMID:18028456

Castro, M-J; Nunes, B; de Vries, B; Lemos, C; Vanmolkot, K R J; van den Heuvel, J J M W; Temudo, T; Barros, J; Sequeiros, J; Frants, R R; Koenderink, J B; Pereira-Monteiro, J M; van den Maagdenberg, A M J M

2008-01-01

121

Analysis of brainwave dominant after horizontal rotation (HR) intervention using EEG for Theta and Delta frequency bands  

Microsoft Academic Search

This paper presents analysis of brainwave dominant after horizontal rotation (HR) intervention using EEG. It was conducted by interviewed all samples. Then, EEG signals were captured from the samples before and after under-going three sessions of HR. Basically, brainwave has four frequency bands which are Alpha, Beta, Theta and Delta. However, this paper will only focus on theta and delta.

R. S. S. A. Kadir; N. Ismail; H. A. Rahman; M. N. Taib; Z. H. Murat; S. Lias

2009-01-01

122

Topographic quantitative EEG sequelae of chronic marihuana use: a replication using medically and psychiatrically screened normal subjects  

Microsoft Academic Search

In two previous studies it was reported that chronic marihuana (THC) use was associated with unique quantitative EEG features which were present in the non-intoxicated state. THC users, as contrasted with controls, had significant elevations of Absolute Power, Relative Power, and Coherence of alpha activity over the bilateral frontal cortex. Furthermore, a quantitative EEG discriminant function analyses permitted a 95%

Frederick A Struve; John J Straumanis; Gloria Patrick; John Leavitt; Joseph E Manno; Barbara R Manno

1999-01-01

123

Osteogenesis imperfecta. The position of substitution for glycine by cysteine in the triple helical domain of the pro alpha 1(I) chains of type I collagen determines the clinical phenotype.  

PubMed Central

Skin fibroblasts grown from three individuals with osteogenesis imperfecta (OI) each synthesized a population of normal type I collagen molecules and additional molecules that had one or two alpha 1(I) chains that contained a cysteine residue within the triple-helical domain, a region from which cysteine normally is excluded. The patients had very different phenotypes. One patient with OI type I had a population of alpha 1(I) chains in which glycine at position 94 of the triple helix was substituted by cysteine; a patient with OI type III had a population of alpha 1(I) chains in which glycine at position 526 of the triple helix was substituted by cysteine; and the third patient, with OI type II, had a cysteine for glycine substitution at position 718 of the alpha 1(I) chain. From all three patients, molecules that contained two mutant chains formed interchain, intramolecular disulfide bonds, and although less stable to thermal denaturation than normal molecules, they were more stable than molecules that contained only a single mutant chain. These findings indicate that substitutions for glycine within the triple-helical domain of the alpha 1(I) chain are not invariably lethal and that their phenotypic effect largely depends on the nature of the substituting residue and its location in the chain. Images

Starman, B J; Eyre, D; Charbonneau, H; Harrylock, M; Weis, M A; Weiss, L; Graham, J M; Byers, P H

1989-01-01

124

Diagnostic accuracy of microEEG: a miniature, wireless EEG device.  

PubMed

Measuring the diagnostic accuracy (DA) of an EEG device is unconventional and complicated by imperfect interrater reliability. We sought to compare the DA of a miniature, wireless, battery-powered EEG device ("microEEG") to a reference EEG machine in emergency department (ED) patients with altered mental status (AMS). Two hundred twenty-five ED patients with AMS underwent 3 EEGs. Two EEGs, EEG1 (Nicolet Monitor, "reference") and EEG2 (microEEG) were recorded simultaneously with EEG cup electrodes using a signal splitter. The remaining study, EEG3, was recorded with microEEG using an electrode cap immediately before or after EEG1/EEG2. The official EEG1 interpretation was considered the gold standard (EEG1-GS). EEG1, 2, and 3 were de-identified and blindly interpreted by two independent readers. A generalized mixed linear model was used to estimate the sensitivity and specificity of these interpretations relative to EEG1-GS and to compute a diagnostic odds ratio (DOR). Seventy-nine percent of EEG1-GS were abnormal. Neither the DOR nor the ?f representing interrater reliabilities differed significantly between EEG1, EEG2, and EEG3. The mean setup time was 27 min for EEG1/EEG2 and 12 min for EEG3. The mean electrode impedance of EEG3 recordings was 12.6 k? (SD: 31.9 k?). The diagnostic accuracy of microEEG was comparable to that of the reference system and was not reduced when the EEG electrodes had high and unbalanced impedances. A common practice with many scientific instruments, measurement of EEG device DA provides an independent and quantitative assessment of device performance. PMID:24727466

Grant, Arthur C; Abdel-Baki, Samah G; Omurtag, Ahmet; Sinert, Richard; Chari, Geetha; Malhotra, Schweta; Weedon, Jeremy; Fenton, Andre A; Zehtabchi, Shahriar

2014-05-01

125

Decreased EEG synchronization in Alzheimer's disease and mild cognitive impairment.  

PubMed

The hypothesis of a functional disconnection of neuro-cognitive networks in patients with mild cognitive impairment (MCI) and Alzheimer Dementia was investigated using baseline resting EEG data. EEG databases from New York (264 subjects) and Stockholm (155 subjects), including healthy controls and patients with varying degrees of cognitive decline or Alzheimer Dementia were analyzed using Global Field Synchronization (GFS), a novel measure of global EEG synchronization. GFS reflects the global amount of phase-locked activity at a given frequency by a single number; it is independent of the recording reference and of implicit source models. Patients showed decreased GFS values in Alpha, Beta, and Gamma frequency bands, and increased GFS values in the Delta band, confirming the hypothesized disconnection syndrome. The results are discussed within the framework of current knowledge about the functional significance of the affected frequency bands. PMID:15582746

Koenig, T; Prichep, L; Dierks, T; Hubl, D; Wahlund, L O; John, E R; Jelic, V

2005-02-01

126

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

127

Volumetric Differences in Mapped Hippocampal Regions Correlate with Increase of High Alpha Rhythm in Alzheimer's Disease  

PubMed Central

Objective. The increase of high alpha relative to low alpha power has been recently demonstrated as a reliable EEG marker of hippocampal atrophy conversion of patients with mild cognitive impairment (MCI) in Alzheimer's disease (AD). In the present study we test the reliability of this EEG index in subjects with AD. Methods. Correlation between EEG markers and volumetric differences in mapped hippocampal regions was estimated in AD patients. Results. Results show that the increase of alpha3/alpha2 power ratio is correlated with atrophy of mapped hippocampal regions in Alzheimer's disease. Conclusions. The findings confirm the possible diagnostic role of EEG markers.

Moretti, D. V.; Prestia, A.; Fracassi, C.; Geroldi, C.; Binetti, G.; Rossini, P. M.; Zanetti, O.; Frisoni, G. B.

2011-01-01

128

Human T-cell receptor (TCR) alpha/beta + CD4-CD8- T cells express oligoclonal TCRs, share junctional motifs across TCR V beta-gene families, and phenotypically resemble memory T cells.  

PubMed Central

Most human T cells express the TCR alpha/beta and either CD4 or CD8 molecules (single positive, SP); however, small numbers lack CD4 and CD8. In inbred mice, alpha/beta CD4-CD8- (double negative, DN) T cells preferentially express certain beta variable region (V beta) families and may arise via unique developmental pathways. Increased percentages of alpha/beta DN T cells have been identified in some human and murine autoimmune and immunodeficiency diseases. However, their contribution to disease pathology or normal immunity is unknown. To study the cell surface phenotype and TCR diversity of human alpha/beta DN T cells, these cells were isolated from the peripheral blood of healthy adults. The proportion of alpha/beta DN T cells expressing molecules associated with activation (HLA-DR), previous exposure to antigen (CD45RO), and cytotoxic function (CD56, CD57, and CD11b) was increased relative to SP T cells. The TCR V beta repertoire of alpha/beta DN T cells was different from that of alpha/beta SP T cells, although most major gene families were present. For example, higher proportions of V beta 11, a minor gene family in peripheral blood leukocytes, were found in most alpha/beta DN T-cell samples. In contrast to mice, no dominant V beta family was used consistently in different human individuals. Within an individual alpha/beta DN T cells possessed an oligoclonal TCR beta repertoire with conservation of several distinct junctional amino acid motifs with one joined to three different V beta genes in two individuals, suggesting that these cells have undergone a selection process driven by a limited set of ligands. The possibility that they may represent, at least in part, originally SP T cells anergized by down-modulation of CD4 or CD8 must also be entertained. Overall, this study demonstrates that human peripheral blood alpha/beta DN T cells possess unique phenotypic and TCR beta repertoire characteristics when compared with the major alpha/beta SP T cell populations and thus may serve specialized immunologic functions and/or have an unusual origin. Images Fig. 4

Brooks, E G; Balk, S P; Aupeix, K; Colonna, M; Strominger, J L; Groh-Spies, V

1993-01-01

129

Respiratory Cycle-Related EEG Changes: Response to CPAP  

PubMed Central

Study Objectives: Respiratory cycle-related EEG changes (RCREC) quantify statistically significant synchrony between respiratory cycles and EEG spectral power, vary to some extent with work of breathing, and may help to predict sleepiness in patients with obstructive sleep apnea. This study was designed to assess the acute response of RCREC to relief of upper airway obstruction by positive airway pressure (PAP). Design: Comparison of RCREC between baseline diagnostic polysomnograms and PAP titration studies. Setting: Accredited academic sleep disorders center. Patients: Fifty adults referred for suspected sleep disordered breathing. Interventions: For each recording, the RCREC in specific physiologic EEG frequency ranges were computed as previously described for the last 3 h of sleep not occupied by apneic events. Results: The sample included 27 women; mean age was 47 ± 11 (SD) years; and median respiratory disturbance index at baseline was 24 (inter-quartile range 15-43). Decrements in RCREC, from baseline to PAP titration, reached 43%, 24%, 14%, 22%, and 31% for delta (P = 0.0004), theta (P = 0.01), alpha (P = 0.10), sigma (P = 0.08), and beta (P = 0.01) EEG frequency ranges, respectively. Within each specific sleep stage, these reductions from baseline to PAP studies in synchrony between EEG power and respiratory cycles still reached significance (P < 0.05) for one or more EEG frequency ranges and for all frequency ranges during REM sleep. Conclusions: RCREC tends to diminish acutely with alleviation of upper airway obstruction by PAP. These data in combination with previous observations support the hypothesis that RCREC reflect numerous, subtle, brief, but consequential inspiratory microarousals. Citation: Chervin RD; Shelgikar AV; Burns JW. Respiratory cycle-related EEG changes: response to CPAP. SLEEP 2012;35(2):203-209.

Chervin, Ronald D.; Shelgikar, Anita Valanju; Burns, Joseph W.

2012-01-01

130

Heritability of EEG coherence in a large sib-pair population  

Microsoft Academic Search

The additive genetic heritability of bipolar EEG coherence in a sample of 305 non-twin sibships comprising 690 individuals (age range 7–65) was estimated. Heritabilities were examined in 6 frequency bands for each of 15 coherence pairs, both interhemispheric and intrahemispheric. The heritabilities of the bipolar EEG coherence ranged from 0.22 to 0.63 in 79 of the 90 phenotypes which had

David B. Chorlian; Yongqiang Tang; Madhavi Rangaswamy; Sean O’Connor; John Rohrbaugh; Robert Taylor; Bernice Porjesz

2007-01-01

131

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.

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

2010-01-01

132

Complex dynamics of epileptic EEG  

Microsoft Academic Search

Electroencephalogram (EEG) - the recorded representation of electrical activity of the brain contain useful information about the state of the brain. Recent studies indicate that nonlinear methods can extract valuable information from neuronal dynamics. We compare the dynamical properties of EEG signals of healthy subjects with epileptic subjects using nonlinear time series analysis techniques. Chaotic invariants like correlation dimension (D2)

N. Kannathal; Sadasivan K Puthusserypady; Lim Choo Min

2004-01-01

133

Relationship of Resting EEG with Anatomical MRI Measures in Individuals at High and Low Risk for Depression  

PubMed Central

Studies have found abnormalities of resting EEG measures of hemispheric activity in depressive disorders. Similar EEG findings and a prominent thinning of the cortical mantle have been reported for persons at risk for depression. The correspondence between EEG alpha power and magnetic resonance imaging (MRI) measures of cortical thickness was examined in a multi-generational study of individuals at risk for depression. Seventy-five participants underwent resting EEG and approximately 5 years later underwent MRI scanning. High-risk participants (n=37) were biological descendants of probands having major depression and low-risk participants (n=38) were descendants of individuals without a history of depression. EEG alpha power was interpolated across the surface of a template brain and coregistered with measures of cortical thickness. Voxel-wise correlations of cortical thickness and alpha power were computed while covarying for age and gender. The high-risk group, when compared to the low-risk group, showed greater alpha asymmetry in an eyes-closed condition, with relatively less activity over right parietal cortex. Alpha power correlated inversely with cortical thickness, particularly over the right posterior region, indicating that EEG evidence of reduced cortical activity was associated with increased cortical thinning. This is the first report of widespread correlation of EEG alpha activity with MRI measures of cortical thickness. Although both EEG and MRI measures are associated with risk for depression, we did not detect evidence that cortical thickness mediated the alpha asymmetry findings. Thus, alpha asymmetry, alone or in combination with MRI, may be a marker of vulnerability for a familial form of depression.

Bruder, Gerard E.; Bansal, Ravi; Tenke, Craig E.; Liu, Jun; Hao, Xuejun; Warner, Virginia; Peterson, Bradley S.; Weissman, Myrna M.

2011-01-01

134

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.

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

2008-01-01

135

Emotion processing in Parkinson's disease: an EEG spectral power study.  

PubMed

Objective: Although an emotional deficit is a common finding in Parkinson's disease (PD), its neurobiological mechanism on emotion recognition is still unknown. This study examined the emotion processing deficits in PD patients using electroencephalogram (EEG) signals in response to multimodal stimuli. Method: EEG signals were investigated on both positive and negative emotions in 14 PD patients and 14 aged-matched normal controls (NCs). The relative power (i.e., ratio of EEG signal power in each frequency band compared to the total EEG power) was computed over three brain regions: the anterior (AF3, F7, F3, F4, F8 and AF4), central (FC5 and FC6) and posterior (T7, P7, O1, O2, P8 and T8) regions for theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz) and gamma (30-60 Hz) frequency sub-bands, respectively. Results: Behaviorally, PD patients showed decreased performance in classifying emotional stimuli as measured by subjective ratings. EEG power at theta, alpha, beta, and gamma bands in all regions were significantly different between the NC and PD groups during both the emotional tasks, with p-values less than 0.05. Furthermore, an increase of relative spectral powers in the theta and gamma bands and a decrease of relative powers in the alpha and beta bands were observed for PD patients compared with NCs during emotional information processing. Conclusion: The results suggest the possibility of the existence of a distinctive neurobiological substrate of PD patients during emotional information processing. Also, these distributed spectral powers in different frequency bands might provide meaningful information about emotional processing in PD patients. PMID:24168328

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

2014-07-01

136

Monitoring carotid test occlusions with continuous EEG and clinical examination.  

PubMed

We routinely monitor invasive neuroradiologic carotid balloon test occlusions with continuous polygraph and quantitative EEG along with repeated detailed clinical examinations. Four of 17 consecutive cases showed changes during carotid occlusion. In one instance, an immediate delta increase was accompanied by slurred speech and aphasia. Another showed alpha attenuation without clinical change. A third patient had significant clinical change without EEG change. Nine of the 17 cases underwent permanent therapeutic carotid occlusion as treatment of an intracerebral vascular abnormality. Seven of these nine had no EEG or clinical changes during monitoring and have had no functional abnormalities on follow-up. The patient with focal alpha attenuation had an accidental balloon detachment but has had no functional or structural neurologic abnormalities. The patient with minor regional increased delta received a permanent carotid occlusion and went on to develop clinical signs 24 h later. We believe that continuous EEG monitoring and repeated clinical examinations provide useful ways of evaluating cerebral circulation during carotid test occlusions. PMID:8408601

Cloughesy, T F; Nuwer, M R; Hoch, D; Vinuela, F; Duckwiler, G; Martin, N

1993-07-01

137

Use of EEG digital filtering and display for HPNS diagnosis.  

PubMed

Divers show symptoms of a condition known as the high pressure nervous syndrome (HPNS) at depths greater than about 180 m. A symptom that possibly lends itself to an objective diagnosis is a change in the frequency content of the EEG signal with increased slow wave (theta, 4-8 Hz) and decreased fast wave (alpha, 8-13 Hz) activity. Therefore, a method was developed, first, to obtain the power in the EEG frequency bands by digital filtering and, second, to display band-indices and ratios during a dive, in a format suitable for rapid appraisal. The formulas for the cascaded 2nd order Butterworth bandpass filters are given together with the corresponding FORTRAN program. EEG signals from 3 subjects taped during the Duke University Atlantis IV dive to a depth of 650 m were analyzed and displayed by the above method as well as by a Fast Fourier Transfer signal analyzer. The results suggest the theta: alpha ratio, which is a one-parameter EEG evaluation in the frequency domain, is a valuable descriptor for the objective HPNS diagnosis. PMID:3705252

Bennett, P B; Janke, N; Kolb, M; Schwieger, E

1986-03-01

138

The spatiospectral characterization of brain networks: fusing concurrent EEG spectra and fMRI maps  

PubMed Central

Different imaging modalities capture different aspects of brain activity. Functional Magnetic Resonance Imaging (fMRI) reveals intrinsic networks whose BOLD signals have periods from 100s (0.01 Hz) to about 10s (0.1 Hz). Electroencephalographic (EEG) recordings, in contrast, commonly reflect cortical electrical fluctuations with periods up to 20 ms (50 Hz) or above. We examined the correspondence between intrinsic fMRI and EEG network activity at rest in order to characterize brain networks both spatially (with fMRI) and spectrally (with EEG). Brain networks were separately identified within the concurrently recorded fMRI and EEG at the aggregate group level with group independent component analysis and the association between spatial fMRI and frequency by spatial EEG sources was examined by deconvolving their component time courses. The two modalities are considered linked if the estimated impulse response function (IRF) is significantly non-zero at biologically plausible delays. We found that negative associations were primarily present within two of five alpha components, which highlights the importance of considering multiple alpha sources in EEG-fMRI. Positive associations were primarily present within the lower (e.g. delta and theta) and higher (e.g. upper beta and lower gamma) spectral regions, sometimes within the same fMRI components. Collectively, the results demonstrate a promising approach to characterize brain networks spatially and spectrally, and reveal that positive and negative associations appear within partially distinct regions of the EEG spectrum.

Bridwell, David A.; Wu, Lei; Eichele, Tom; Calhoun, Vince D.

2013-01-01

139

The spatiospectral characterization of brain networks: fusing concurrent EEG spectra and fMRI maps.  

PubMed

Different imaging modalities capture different aspects of brain activity. Functional magnetic resonance imaging (fMRI) reveals intrinsic networks whose BOLD signals have periods from 100 s (0.01 Hz) to about 10s (0.1 Hz). Electroencephalographic (EEG) recordings, in contrast, commonly reflect cortical electrical fluctuations with periods up to 20 ms (50 Hz) or above. We examined the correspondence between intrinsic fMRI and EEG network activity at rest in order to characterize brain networks both spatially (with fMRI) and spectrally (with EEG). Brain networks were separately identified within the concurrently recorded fMRI and EEG at the aggregate group level with group independent component analysis and the association between spatial fMRI and frequency by spatial EEG sources was examined by deconvolving their component time courses. The two modalities are considered linked if the estimated impulse response function (IRF) is significantly non-zero at biologically plausible delays. We found that negative associations were primarily present within two of five alpha components, which highlights the importance of considering multiple alpha sources in EEG-fMRI. Positive associations were primarily present within the lower (e.g. delta and theta) and higher (e.g. upper beta and lower gamma) spectral regions, sometimes within the same fMRI components. Collectively, the results demonstrate a promising approach to characterize brain networks spatially and spectrally, and reveal that positive and negative associations appear within partially distinct regions of the EEG spectrum. PMID:23266744

Bridwell, David A; Wu, Lei; Eichele, Tom; Calhoun, Vince D

2013-04-01

140

A Dry EEG-System for Scientific Research and Brain-Computer Interfaces  

PubMed Central

Although it ranks among the oldest tools in neuroscientific research, electroencephalography (EEG) still forms the method of choice in a wide variety of clinical and research applications. In the context of brain–computer interfacing (BCI), EEG recently has become a tool to enhance human–machine interaction. EEG could be employed in a wider range of environments, especially for the use of BCI systems in a clinical context or at the homes of patients. However, the application of EEG in these contexts is impeded by the cumbersome preparation of the electrodes with conductive gel that is necessary to lower the impedance between electrodes and scalp. Dry electrodes could provide a solution to this barrier and allow for EEG applications outside the laboratory. In addition, dry electrodes may reduce the time needed for neurological exams in clinical practice. This study evaluates a prototype of a three-channel dry electrode EEG system, comparing it to state-of-the-art conventional EEG electrodes. Two experimental paradigms were used: first, event-related potentials (ERP) were investigated with a variant of the oddball paradigm. Second, features of the frequency domain were compared by a paradigm inducing occipital alpha. Furthermore, both paradigms were used to evaluate BCI classification accuracies of both EEG systems. Amplitude and temporal structure of ERPs as well as features in the frequency domain did not differ significantly between the EEG systems. BCI classification accuracies were equally high in both systems when the frequency domain was considered. With respect to the oddball classification accuracy, there were slight differences between the wet and dry electrode systems. We conclude that the tested dry electrodes were capable to detect EEG signals with good quality and that these signals can be used for research or BCI applications. Easy to handle electrodes may help to foster the use of EEG among a wider range of potential users.

Zander, Thorsten Oliver; Lehne, Moritz; Ihme, Klas; Jatzev, Sabine; Correia, Joao; Kothe, Christian; Picht, Bernd; Nijboer, Femke

2010-01-01

141

Operant control of EEG and event-related and slow brain potentials  

Microsoft Academic Search

Research on operant control of brain potentials is reviewed. From single-unit firing and spontaneous EEG activity to event-related potentials such as sensory and pain evoked potentials, and slow potential shifts, most of the aspects of electrical brain activity have been investigated. Results produced by conditioning of spontaneous EEG oscillations (alpha and theta) dampened the early enthusiasm: e.g., no increase above

Brigitte Rockstroh; Niels Birbaumer; Thomas Elbert; Werner Lutzenberger

1984-01-01

142

Dry EEG electrodes.  

PubMed

Electroencephalography (EEG) emerged in the second decade of the 20th century as a technique for recording the neurophysiological response. Since then, there has been little variation in the physical principles that sustain the signal acquisition probes, otherwise called electrodes. Currently, new advances in technology have brought new unexpected fields of applications apart from the clinical, for which new aspects such as usability and gel-free operation are first order priorities. Thanks to new advances in materials and integrated electronic systems technologies, a new generation of dry electrodes has been developed to fulfill the need. In this manuscript, we review current approaches to develop dry EEG electrodes for clinical and other applications, including information about measurement methods and evaluation reports. We conclude that, although a broad and non-homogeneous diversity of approaches has been evaluated without a consensus in procedures and methodology, their performances are not far from those obtained with wet electrodes, which are considered the gold standard, thus enabling the former to be a useful tool in a variety of novel applications. PMID:25046013

Lopez-Gordo, M A; Morillo, D Sanchez; Valle, F Pelayo

2014-01-01

143

An alpha modulation index for electroencephalographic studies using complex demodulation  

Microsoft Academic Search

An automated technique for measuring the relative amount of amplitude modulation of electroencephalographic (EEG) alpha activity\\u000a is developed to increase the number of existing tools for differentiating the various types of alpha activity. EEG data collected\\u000a from 12 normal males is used to characterize alpha modulation frequency characteristics. From these findings, a complex demodulation\\u000a method is constructed to extract the

M. J. Schroeder; R. E. Barr

2000-01-01

144

Distinct Transient Outward Potassium Current (Ito) Phenotypes and Distribution of Fast-inactivating Potassium Channel Alpha Subunits in Ferret Left Ventricular Myocytes  

Microsoft Academic Search

The biophysical characteristics and a subunits underlying calcium-independent transient outward potassium current (I to ) phenotypes expressed in ferret left ventricular epicardial (LV epi) and endocardial (LV endo) myocytes were analyzed using patch clamp, fluorescent in situ hybridization (FISH), and immunofluores- cent (IF) techniques. Two distinct I to phenotypes were measured (21-22 8 C) in the majority of LV epi

Mulugu V. Brahmajothi; Donald L. Campbell; Randall L. Rasmusson; Michael J. Morales; James S. Trimmer; Jeanne M. Nerbonne; Harold C. Strauss

1999-01-01

145

Phenotypic consequences of deletion of the {gamma}{sub 3}, {alpha}{sub 5}, or {beta}{sub 3} subunit of the type A {gamma}-aminobutyric acid receptor in mice  

SciTech Connect

Three genes (Gabrg3, Gabra5, and Gabrb3) encoding the {gamma}{sub 3}, {alpha}{sub 5}, and {beta}{sub 3} subunits of the type A {gamma}-aminobutyric acid receptor, respectively, are known to map near the pink-eyed dilution (p) locus in mouse chromosome 7. This region shares homology with a segment of human chromosome 15 that is implicated in Angelman syndrome, an inherited neurobehavioral disorder. By mapping Gabrg3-Gabra5-Gabrb3-telomere. Like Gabrb3, neither the Gabra5 nor Gabrg3 gene is functionally imprinted in adult mouse brain. Mice deleted for all three subunits die at birth with a cleft palate, although there are rare survivors ({approximately} 5%) that do not have a cleft palate but do exhibit a neurological abnormality characterized by tremor, jerky gait, and runtiness. The authors have previously suggested that deficiency of the {beta}{sub 3} subunit may be responsible for the clefting defect. Most notably, however, in this report they describe mice carrying two overlapping, complementing p deletions that fail to express the {gamma}{sub 3} transcript, as well as mice from another line that express neither the {gamma}{sub 3} nor {alpha}{sub 5} transcripts. Surprisingly, mice from both of these lines are phenotypically normal and do not exhibit any of the neurological symptoms characteristic of the rare survivors that are deleted for all three ({gamma}{sub 3}, {alpha}{sub 5}, and {beta}{sub 3}) subunits. These mice therefore provide a whole-organism type A {gamma}-aminobutyric-acid receptor background that is devoid of any receptor subtypes that normally contain the {gamma}{sub 3} and/or {alpha}{sub 5} subunits. The absence of an overt neurological phenotype in mice lacking the {gamma}{sub 3} and/or {alpha}{sub 5} subunits also suggests that mutations in these genes are unlikely to provide useful animal models for Angelman syndrome in humans.

Culia, C.T.; Stubbs, L.J.; Montgomery, C.S.; Russell, L.B.; Rinchik, E.M. [Oak Ridge National Lab., TN (United States)

1994-03-29

146

A restriction fragment length polymorphism in the pigeon pro alpha 2(1) collagen gene: lack of an allelic association with an atherogenic phenotype in pigeons genetically susceptible to the development of spontaneous atherosclerosis.  

PubMed

A high frequency restriction fragment length polymorphism (RFLP) at the 3'-end of the pigeon pro alpha 2(1) collagen gene was detected using the restriction endonuclease EcoR1. The distribution of this allelic variant was analyzed in DNA isolated from White Carneau pigeons genetically susceptible to the development of spontaneous atherosclerosis. The atherogenic phenotype in individual pigeons was measured by the determination of total cholesterol and cholesterol ester levels in the celiac focus of the thoracic aorta of adult White Carneau pigeons. Aortic wall cholesterol levels correlated with an increase in lesion size. No correlation, however, was observed between allelic variants of the pigeon pro alpha 2(1) collagen gene and the atherogenic phenotype in White Carneau pigeons suggesting lack of linkage between this allelic marker and the genetic susceptibility to spontaneous atherogenesis. This is the first study of its kind in this animal model and serves to provide a basis for the further analysis of co-segregation of RFLPS in candidate genes to this polygenic phenotype. PMID:1685110

Boyd, C D; Song, J Y; Kniep, A C; Park, H S; Fastnacht, C; Smith, E C; Smith, S C

1991-01-01

147

EEG and Cerebral Blood Flow Velocity Abnormalities in Chronic Cocaine Users  

PubMed Central

EEG and cerebral blood flow abnormalities have been documented in chronic cocaine abusers. To identify possible relationships between EEG and blood flow changes and their relationship to the intensity of cocaine use, we recorded the resting eyes-closed EEG and anterior (ACA) and middle (MCA) cerebral artery blood flow velocity during systole (VS) and diastole (VD) by transcranial Doppler (TCD) sonography of 99 (76 male, 23 female; mean [SD] age 34.3 [5.2] years, 8.6 [5.5] years of cocaine use, 17.8 [7.7] days of cocaine use in month prior to screening) cocaine users within 5 days of admission to a closed research unit. Forty-two non-drug-using, age-matched control subjects (22 male, 20 female) were tested as outpatients. A 3-minute period of resting EEG was recorded from 16 standard scalp electrodes. Artifact-free EEG was converted to six frequency bands (delta, theta, alpha1, alpha2, beta1 and beta2) using a Fast Fourier Transform. Pulsatility index (PI) was calculated as a measure of small vessel resistance. Cocaine users had decreased VD and increased PI in the MCA, with no difference in VS, and reduced EEG theta, beta1 and beta2 absolute power in posterior brain regions. Recent cocaine use was positively associated with MCA PI (r = 0.27, p < 0.001) and negatively associated with low frequency EEG power (delta power: r = ?0.25, p < 0.002; theta power: r = ?0.29, p< 0.001). EEG beta1 (r = ?0.211, p < 0.05) and beta2 (r = ?0.176, p < 0.05) power measures were correlated with PI. These observations suggest that EEG and TCD changes reflect related physiological processes during early cocaine abstinence.

Copersino, Marc L.; Herning, Ronald I.; Better, Warren; Cadet, Jean-Lud; Gorelick, David A.

2012-01-01

148

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

149

[Quantitative and topographic EEG brain mapping: a study of normal adult population].  

PubMed

We studied the electric brain activity during wakefulness in 20 Brazilian people through digital EEG and spectral analysis in order to propose a standardization for Brazilian adult population. All this group is healthy with laboratory examinations and mini-mental state (scores higher than 27) evaluation normal. After Fourier fast transformation (FFT) calculation, we found a histogram display with monomodal distribution, with higher values in alpha band. Analyzing the average of these results, different standards from the analogical traditional EEG were found, as the distribution of alpha band and delta activity behavior. The beta 2 and beta 3 behavior showed a diffuse distribution, that is not the usual. By the other hand, other findings are congruent to the analogical EEG as the alpha posterior predominance and the bigger presence of theta activity at the central regions. PMID:9686121

Anghinah, R; Kanda, P A; Jorge, M S; Melo, A C

1998-03-01

150

The functional Val158Met polymorphism of COMT predicts interindividual differences in brain alpha oscillations in young men.  

PubMed

Individual patterns of the electroencephalogram (EEG) in wakefulness and sleep are among the most heritable traits in humans, yet distinct genetic and neurochemical mechanisms underlying EEG phenotypes are largely unknown. A functional polymorphism in the gene encoding catechol-O-methyltransferase (COMT), an enzyme playing an important role in cortical dopamine metabolism, causes a common substitution of methionine (Met) for valine (Val) at codon 158 of COMT protein. Val allele homozygotes exhibit higher COMT activity and lower dopaminergic signaling in prefrontal cortex than Met/Met homozygotes. Evidence suggests that this polymorphism affects executive functions in healthy individuals. We hypothesized that it also modulates functional aspects of EEG in wakefulness and sleep. EEG recordings were conducted twice on separate occasions in 10 Val/Val and 12 Met/Met allele carriers (all men) in wakefulness, and in baseline and recovery sleep before and after 40 h prolonged waking. During sleep deprivation, subjects received placebo and modafinil in randomized, cross-over manner. We show that the Val158Met polymorphism predicts stable and frequency-specific, interindividual variation in brain alpha oscillations. Alpha peak frequency in wakefulness was 1.4 Hz slower in Val/Val genotype than in Met/Met genotype. Moreover, Val/Val allele carriers exhibited less 11-13 Hz activity than Met/Met homozygotes in wakefulness, rapid-eye-movement (REM) sleep, and non-REM sleep. This difference was resistant against the effects of sleep deprivation and modafinil. The data demonstrate that mechanisms involving COMT contribute to interindividual differences in brain alpha oscillations, which are functionally related to executive performance such as counting tendency on a random number generation task in young adults. PMID:19726643

Bodenmann, Sereina; Rusterholz, Thomas; Dürr, Roland; Stoll, Claudia; Bachmann, Valérie; Geissler, Eva; Jaggi-Schwarz, Karin; Landolt, Hans-Peter

2009-09-01

151

Effects of early intervention on EEG power and coherence in previously institutionalized children in Romania.  

PubMed

Two groups of Romanian children were compared on spectral power and coherence in the electroencephalogram (EEG) in early childhood. One group consisted of previously institutionalized children who had been randomly assigned to a foster care intervention at a mean age of 23 months. The second group had been randomized to remain in institutional care. Because of a policy of noninterference, a number of these children also experienced placement into alternative family care environments. There were minimal group differences between the foster care and institutionalized groups in EEG power and coherence across all measured frequency bands at 42 months of age. However, age at foster care placement within the foster care group was correlated with certain measures of EEG power and coherence. Earlier age at foster care placement was associated with increased alpha power and decreased short-distance EEG coherence. Further analyses separating age at placement from duration of intervention suggest that this effect may be more robust for EEG coherence than EEG band power. Supplementary analyses examined whether the EEG measures mediated changes in intellectual abilities within the foster care children, but no clear evidence of mediation was observed. PMID:18606035

Marshall, Peter J; Reeb, Bethany C; Fox, Nathan A; Nelson, Charles A; Zeanah, Charles H

2008-01-01

152

Exon-intron structure of the human neuronal nicotinic acetylcholine receptor {alpha}4 subunit (CHRNA4)  

SciTech Connect

The human neuronal nicotinic acetylcholine receptor {alpha}4 subunit gene (CHRNA4) is located in the candidate region for three different phenotypes: benign familial neonatal convulsions, autosomal dominant nocturnal frontal lobe epilepsy, and low-voltage EEG. Recently, a missense mutation in transmembrane domain 2 of CHRNA4 was found to be associated with autosomal dominant nocturnal frontal lobe epilepsy in one extended pedigree. We have determined the genomic organization of CHRNA4, which consists of six exons distributed over approximately 17 kb of genomic DNA. The nucleotide sequence obtained from the genomic regions adjacent to the exon boundaries enabled us to develop a set of primer pairs for PCR amplification of the complete coding region. The sequence analysis provides the basis for a comprehensive mutation screening of CHRNA4 in the above-mentioned phenotypes and possibly in other types of idopathic epilepsies. 29 refs., 3 figs., 1 tab.

Steinlein, O.; Weiland, S.; Stoodt, J.; Propping, P. [Univ. of Bonn (Germany)] [Univ. of Bonn (Germany)

1996-03-01

153

Optimizing microsurgical skills with EEG neurofeedback  

PubMed Central

Background By enabling individuals to self-regulate their brainwave activity in the field of optimal performance in healthy individuals, neurofeedback has been found to improve cognitive and artistic performance. Here we assessed whether two distinct EEG neurofeedback protocols could develop surgical skill, given the important role this skill plays in medicine. Results National Health Service trainee ophthalmic microsurgeons (N = 20) were randomly assigned to either Sensory Motor Rhythm-Theta (SMR) or Alpha-Theta (AT) groups, a randomized subset of which were also part of a wait-list 'no-treatment' control group (N = 8). Neurofeedback groups received eight 30-minute sessions of EEG training. Pre-post assessment included a skills lab surgical procedure with timed measures and expert ratings from video-recordings by consultant surgeons, together with state/trait anxiety self-reports. SMR training demonstrated advantages absent in the control group, with improvements in surgical skill according to 1) the expert ratings: overall technique (d = 0.6, p < 0.03) and suture task (d = 0.9, p < 0.02) (judges' intraclass correlation coefficient = 0.85); and 2) with overall time on task (d = 0.5, p = 0.02), while everyday anxiety (trait) decreased (d = 0.5, p < 0.02). Importantly the decrease in surgical task time was strongly associated with SMR EEG training changes (p < 0.01), especially with continued reduction of theta (4–7 Hz) power. AT training produced marginal improvements in technique and overall performance time, which were accompanied by a standard error indicative of large individual differences. Notwithstanding, successful within session elevation of the theta-alpha ratio correlated positively with improvements in overall technique (r = 0.64, p = 0.047). Conclusion SMR-Theta neurofeedback training provided significant improvement in surgical technique whilst considerably reducing time on task by 26%. There was also evidence that AT training marginally reduced total surgery time, despite suboptimal training efficacies. Overall, the data set provides encouraging evidence of optimised learning of a complex medical specialty via neurofeedback training.

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

2009-01-01

154

Bristle-sensors--low-cost flexible passive dry EEG electrodes for neurofeedback and BCI applications.  

PubMed

In this paper, we present a new, low-cost dry electrode for EEG that is made of flexible metal-coated polymer bristles. We examine various standard EEG paradigms, such as capturing occipital alpha rhythms, testing for event-related potentials in an auditory oddball paradigm and performing a sensory motor rhythm-based event-related (de-) synchronization paradigm to validate the performance of the novel electrodes in terms of signal quality. Our findings suggest that the dry electrodes that we developed result in high-quality EEG recordings and are thus suitable for a wide range of EEG studies and BCI applications. Furthermore, due to the flexibility of the novel electrodes, greater comfort is achieved in some subjects, this being essential for long-term use. PMID:21436526

Grozea, Cristian; Voinescu, Catalin D; Fazli, Siamac

2011-04-01

155

Bristle-sensors—low-cost flexible passive dry EEG electrodes for neurofeedback and BCI applications  

NASA Astrophysics Data System (ADS)

In this paper, we present a new, low-cost dry electrode for EEG that is made of flexible metal-coated polymer bristles. We examine various standard EEG paradigms, such as capturing occipital alpha rhythms, testing for event-related potentials in an auditory oddball paradigm and performing a sensory motor rhythm-based event-related (de-) synchronization paradigm to validate the performance of the novel electrodes in terms of signal quality. Our findings suggest that the dry electrodes that we developed result in high-quality EEG recordings and are thus suitable for a wide range of EEG studies and BCI applications. Furthermore, due to the flexibility of the novel electrodes, greater comfort is achieved in some subjects, this being essential for long-term use.

Grozea, Cristian; Voinescu, Catalin D.; Fazli, Siamac

2011-04-01

156

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

157

[A comparison of the results of topographic EEG mapping with the data from a neurological examination and computed tomography of the brain].  

PubMed

The data of topographic EEG brain mapping were compared to neurological evidence and CT data in 6 patients with organic lesions (sequelae of vertebrobasilar ischemic stroke, brain atrophy, brain tumor). Cortical activity typical for these nosological entities appeared on the EEG maps. In 5 out of 6 patients foci of alpha- and delta-activity indicated the location of the lesion. The authors suggest that EEG brain mapping of the large number of patients with neural and mental diseases will provide insight into pathogenetic mechanisms of these diseases. The authors also think it necessary for patients undergoing EEG brain mapping to be examined neurologically. PMID:8009928

Lukacher, G Ia; Strelets, V B; Marsakova, G D; Golikova, Zh V

1994-01-01

158

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.

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

2013-01-01

159

Diagnostic usefulness of linear and nonlinear quantitative EEG analysis in Alzheimer's disease.  

PubMed

The sensitivity of the EEG in early AD is somewhat limited. In this respect spectral analysis is little better than visual assessment. In this study we address the question whether a new type of EEG analysis derived from chaos theory can improve the sensitivity of the EEG. EEGs were recorded in 15 control subjects and 15 patients with mild AD. The EEG recorded at 02 and 01 during eyes closed and eyes open conditions was subjected to spectral analysis (relative power) and nonlinear analysis (calculation of the correlation dimension D2). AD patients had more relative theta power and impaired reactivity in alpha, delta and theta bands. Also, reactivity of the D2 was impaired in AD subjects. For a specificity of 100%, relative theta power had the highest sensitivity (46.7%). Alpha band reactivity at O1 had a sensitivity of 40% and D2 reactivity at O1 had a sensitivity of 33.3%. Combining theta power with alpha reactivity resulted in a sensitivity of 53.3%; combining theta with D2 reactivity resulted in a sensitivity of 60%. Used in isolation, linear analysis was superior in differentiating AD patients from controls. The best results were obtained by combining linear with nonlinear measures. This approach does not seem practical yet, but deserves further study. PMID:8681465

Stam, C J; Jelles, B; Achtereekte, H A; van Birgelen, J H; Slaets, J P

1996-04-01

160

[Post-radiation effect on the interhemispheric asymmetry in EEG and thermography characteristics].  

PubMed

Complex analysis of EEG and thermographic parameters carried out in 10 healthy subjects and 34 patients, Chernobyl clean-up participants revealed a correlation between EEG and brain temperature changes in the baseline state and during mental arithmetic. During cognitive activity the maximal increase in the average EEG coherence and temperature shifts in healthy subjects were observed in the left frontotemporal and right parietotemporal areas. In patients changes in both parameters under study were most pronounced, the interhemispheric relations were impaired. The visual analysis revealed "flat" and "hypersynchronous" EEG types in patients. The dominant pathologic activity in the betal range indicative of mediobasal and oral brainstem lesions was characteristic of the flat EEG. This type of activity was observed in 60% of patients. In these cases, a general decrease in EEG coherence and temperature was most pronounced in the left hemisphere. The hypersynchronou EEG type (40% patients) was characterized by paroxysmal activity in the theta and alpha ranges suggesting diencephalic brain lesions. In these cases, EEG coherence and temperature were more variable; changes in the right hemisphere were significant, be it increase or decrease. Our complex approach to investigation of brain activity in different aspects seems to be promising in estimation of the brain functional state both in healthy persons and patients in remote terms after exposure to radiation. The specific hemispheric temperature changes revealed in Chernobyl patients especially during cognitive activity can be the sequels of postradiation disorders of vascular neuro-circulation. The EEG findings suggest subcortical disorders at different levels (diencephalic or brainstem) and functional failure of the right or left hemispheres in remote terms after exposure to radiation. PMID:14598548

Zhavoronkova, L A; Gabova, A V; Kuznetsova, G D; Sel'ski?, A G; Pasechnik, V I; Kholodova, N B; Ianovich, A V

2003-01-01

161

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

162

EEG source analysis using space mapping techniques  

Microsoft Academic Search

The electroencephalogram (EEG) measures potential differences, generated by electrical activity in brain tissue, between scalp electrodes. The EEG potentials can be calculated by the quasi-static Poisson equation in a certain head model. It is well known that the electrical dipole (source) which best fits the measured EEG potentials is obtained by an inverse problem. The dipole parameters are obtained by

G. Crevecoeur; H. Hallez; P. Van Hese; Y. D’Asseler; L. Dupre; R. Van de Walle

2008-01-01

163

EEG classification using generative independent component analysis  

Microsoft Academic Search

We present an application of Independent Component Analysis (ICA) to the dis- crimination of mental tasks for EEG-based Brain Computer Interface systems. ICA is most commonly used with EEG for artifact identification with little work on the use of ICA for direct discrimination of different types of EEG signals. By view- ing ICA as a generative model, we can use

Silvia Chiappa; David Barber

2006-01-01

164

EEG signal analysis: a survey.  

PubMed

The EEG (Electroencephalogram) signal indicates the electrical activity of the brain. They are highly random in nature and may contain useful information about the brain state. However, it is very difficult to get useful information from these signals directly in the time domain just by observing them. They are basically non-linear and nonstationary in nature. Hence, important features can be extracted for the diagnosis of different diseases using advanced signal processing techniques. In this paper the effect of different events on the EEG signal, and different signal processing methods used to extract the hidden information from the signal are discussed in detail. Linear, Frequency domain, time - frequency and non-linear techniques like correlation dimension (CD), largest Lyapunov exponent (LLE), Hurst exponent (H), different entropies, fractal dimension(FD), Higher Order Spectra (HOS), phase space plots and recurrence plots are discussed in detail using a typical normal EEG signal. PMID:20433058

Subha, D Puthankattil; Joseph, Paul K; Acharya U, Rajendra; Lim, Choo Min

2010-04-01

165

EEG correlates of time-varying BOLD functional connectivity  

PubMed Central

Recent resting-state fMRI studies have shown that the apparent functional connectivity (FC) between brain regions may undergo changes on time-scales of seconds to minutes, the basis and importance of which are largely unknown. Here, we examine the electrophysiological correlates of within-scan FC variations during a condition of eyes-closed rest. A sliding window analysis of simultaneous EEG-fMRI data was performed to examine whether temporal variations in coupling between three major networks (default mode; DMN, dorsal attention; DAN, and salience network; SN) are associated with temporal variations in mental state, as assessed from the amplitude of alpha and theta oscillations in the EEG. In our dataset, alpha power showed a significant inverse relationship with the strength of connectivity between DMN and DAN. In addition, alpha power covaried with the spatial extent of anticorrelation between DMN and DAN, with higher alpha power associated with larger anticorrelation extent. Results suggest an electrical signature of the time-varying FC between the DAN and DMN, potentially reflecting neural and state-dependent variations.

Chang, Catie; Liu, Zhongming; Chen, Michael C.; Liu, Xiao; Duyn, Jeff H.

2013-01-01

166

Pharmaco-EEG in psychiatry.  

PubMed

In spite of its origins deeply rooted in the discipline, pharmaco-EEG applications in psychiatry remain limited to its achievements in the field of psychotropic drugs classification and, in few instances, discovery. In the present paper two attempts to transfer pharmaco-EEG methods to psychiatric clinical routine will be described: 1) monitoring of psychotropic drug toxicity at the central nervous system level, and 2) prediction of clinical response to treatment with psychotropic drugs. Both applications have been the object of several investigations providing promising and sometimes consistent findings which, however, had no impact on clinical practice. For the first topic, the review is limited to antipsychotics, lithium and recreational drugs, as for other psychotropic drugs mostly case studies are available, while for the response prediction it will include antipsychotics, antidepressants, anxiolytics, psychostimulants and nootropics. In spite of several methodological limitations, pharmaco-EEG studies dealing with monitoring of antipsychotic- and lithium-induced EEG abnormalities went close to, but never became, a clinical routine. EEG studies of recreational drugs are flawed by several limitations, and failed, so far, to identify reliable indices of CNS toxicity to be used in clinical settings. Several QEEG studies on early predictors of treatment response to first generation antipsychotics have produced consistent findings, but had no clinical impact. For other psychotropic drug classes few and inconsistent reports have appeared. Pharmaco-EEG had the potential for important clinical applications, but so far none of them entered clinical routine. The ability to upgrade theories and methods and promote large scale studies represent the future challenge. PMID:16733940

Mucci, Armida; Volpe, Umberto; Merlotti, Eleonora; Bucci, Paola; Galderisi, Silvana

2006-04-01

167

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

168

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

169

The EEG after alcohol administration in men at risk for alcoholism.  

PubMed

The biologic sons of alcoholics constitute a group at high risk (HR) for alcoholism. A 0.5-g/kg dose of alcohol was administered to HR and control subjects aged 19 to 21 years. Blood alcohol concentration measurements failed to distinguish HR from control subjects, but quantitative measurements of EEG alpha activity differentiated them. The HR subjects exhibited greater increases in slow alpha energy and greater decreases of fast alpha energy after alcohol administration than controls; the HR subjects also showed greater decreases in mean alpha frequency after alcohol administration. These EEG findings suggest that subjects at high risk for alcoholism are physiologically more sensitive to alcohol than control subjects. PMID:6870482

Pollock, V E; Volavka, J; Goodwin, D W; Mednick, S A; Gabrielli, W F; Knop, J; Schulsinger, F

1983-08-01

170

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.

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

171

Resting State EEG Power and Coherence Abnormalities in Bipolar Disorder and Schizophrenia  

PubMed Central

Resting state electroencephalogram (EEG) abnormalities in schizophrenia and bipolar disorder patients suggest alterations in neural oscillatory activity. However, few studies directly compare these anomalies between patient groups, and none have examined EEG coherence. Therefore, this study investigated whether these electrophysiological characteristics differentiate clinical populations from one another, and from non-psychiatric controls. To address this question, resting EEG power and coherence were assessed in 76 bipolar patients (BP), 132 schizophrenia patients (SZ), and 136 non-psychiatric controls (NC). We conducted separate repeated-measures ANOVAs to examine group differences within seven frequency bands across several brain regions. BP showed significantly greater power relative to SZ at higher frequencies including Beta and Gamma across all regions. In terms of intra-hemispheric coherence, while SZ generally exhibited higher coherence at Delta compared to NC and BP, both SZ and BP showed higher coherence at Alpha1 and Alpha2. In contrast, BP and HC showed higher coherence within hemispheres compared to SZ at Beta 1. In terms of inter-hemispheric coherence, SZ displayed higher coherence compared to NC at temporal sites at both Alpha1 and Alpha2. Taken together, BP exhibited increased high frequency power with few disruptions in neural synchronization. In contrast, SZ generally exhibited enhanced synchronization within and across hemispheres. These findings suggest that resting EEG can be a sensitive measure for differentiating between clinical disorders.

Kam, Julia W. Y.; Bolbecker, Amanda R.; O'Donnell, Brian F.; Hetrick, William P.; Brenner, Colleen A.

2014-01-01

172

EEG oscillatory states as neuro-phenomenology of consciousness as revealed from patients in vegetative and minimally conscious states.  

PubMed

The value of resting electroencephalogram (EEG) in revealing neural constitutes of consciousness (NCC) was examined. We quantified the dynamic repertoire, duration and oscillatory type of EEG microstates in eyes-closed rest in relation to the degree of expression of clinical self-consciousness. For NCC a model was suggested that contrasted normal, severely disturbed state of consciousness and state without consciousness. Patients with disorders of consciousness were used. Results suggested that the repertoire, duration and oscillatory type of EEG microstates in resting condition quantitatively related to the level of consciousness expression in brain-damaged patients and healthy-conscious subjects. Specifically, results demonstrated that (a) decreased number of EEG microstate types was associated with altered states of consciousness, (b) unawareness was associated with the lack of diversity in EEG alpha-rhythmic microstates, and (c) the probability for the occurrence and duration of delta-, theta- and slow-alpha-rhythmic microstates were associated with unawareness, whereas the probability for the occurrence and duration of fast-alpha-rhythmic microstates were associated with consciousness. In conclusion, resting EEG has a potential value in revealing NCC. This work may have implications for clinical care and medical-legal decisions in patients with disorders of consciousness. PMID:22054641

Fingelkurts, Alexander A; Fingelkurts, Andrew A; Bagnato, Sergio; Boccagni, Cristina; Galardi, Giuseppe

2012-03-01

173

HIF-1 Alpha-Induced Up-Regulation of miR-9 Contributes to Phenotypic Modulation in Pulmonary Artery Smooth Muscle Cells During Hypoxia.  

PubMed

Pulmonary artery smooth muscle cells (PASMCs) are associated with the development of hypoxic pulmonary hypertension (HPH). Recent studies have implicated a critical role for microRNAs (miRNAs) in HPH; however, their expression and regulation in hypoxia-mediated phenotypic modulation of PASMCs remains largely unclear. Here, we report that miR-9 was induced in hypoxia and involved in a hypoxia-induced phenotypic switch in rat primary PASMCs. Knockdown of miR-9 followed by hypoxia exposure attenuated PASMCs proliferation and enhanced the expression of contractile genes in vascular smooth muscle cells (VSMCs), while overexpression of miR-9 in normoxia promoted a proliferative phenotype in PASMCs. The primary transcripts of miR-9-1 and miR-9-3, but not miR-9-2, increased dramatically after hypoxia, whereas silencing of the hypoxia-associated transcription factor HIF-1? following hypoxia exposure abolished the enhancement of both primary transcripts in PASMCs. Using in silico analysis, we found three putative HIF-1? binding motifs on miR-9-1 and one motif on miR-9-3 located within the 5-kb region upstream of the transcriptional start sites. Chromatin immunoprecipitation assay revealed that hypoxia enhanced the direct interaction between HIF-1? and the regulatory elements of miR-9-1 and miR-9-3. Reporter assays showed that the regulatory regions of miR-9-1 and miR-9-3 behaved as enhancers in a HIF-1?-dependent manner during hypoxia. Taken together, our data uncover a regulatory mechanism involving HIF-1?-mediated up-regulation of miR-9, which plays a role in the hypoxia-induced phenotypic switch of PASMCs. J. Cell. Physiol. 229: 1511-1520, 2014. © 2014 Wiley Periodicals, Inc. PMID:24615545

Shan, Fabo; Li, Junxia; Huang, Qing-Yuan

2014-10-01

174

Observations on EEG patterns in neurally-mediated syncope: an inspective and quantitative study.  

PubMed

We performed an observational EEG study in 43 patients with neurally-mediated syncope in basal condition and during hyperventilation (HV), and compared it with 32 healthy controls. On blind analysis at rest, EEG was classified as normal in 47% of patients (vs. 94% of controls, P < 0.001). More abundant and pronounced delta-theta activities and alpha slowing were found in patients than in control subjects on both visual inspection and quantitative spectral analysis. During prolonged HV, the EEG remained normal in 21% of patients only. Slow activities became more evident in patients than in control subjects, and intermittent rhythmic delta activity appeared in 40% of syncopal patients. These "pseudoparoxysmal" EEG changes differed from the common slowings induced by HV in adult subjects and were not observed in our control subjects. Moreover, these distinctive EEG changes, a common finding in syncopal patients, could not be confused with epileptiform activity of any kind. Further studies will clarify the pathophysiology of these EEG modifications. PMID:15639129

Mecarelli, O; Pulitano, P; Vicenzini, E; Vanacore, N; Accornero, N; De Marinis, M

2004-12-01

175

Utilization of a two-channel, microprocessor-based EEG device for monitoring cognitively vulnerable patients.  

PubMed

Several experiments were conducted to validate the use of a two-channel microprocessor-based electroencephalographic (EEG) device for detecting changes in EEG background rhythm in the clinic or at the bedside. The reliability of background measures in healthy individuals was evaluated by obtaining EEG data on 20 control subjects on two occasions separated by at least 1 day. The sensitivity to an experimental toxic encephalopathy was evaluated using measures of EEG and the Buschke Memory Selective Reminding Test after the administration of scopolamine hydrobromide, 0.86 mg subcutaneously, to three healthy volunteers. Postdrug measures of the EEG showed significant group differences from controls at 1 and 2 hours for relative alpha and relative theta power. The drug-induced change for each individual exceeded the predicted range calculated from data on control subjects. These findings suggest the feasibility and the potential utility of this method. This approach was extended to the elderly with measures on 102 subjects (average age, 85 years) living in an institutional setting. EEG measures in the population were of acceptable reliability and were significantly correlated with Mini-Mental State Examination (MMSE) scores (r = -.375 for theta and .357 for beta). Preliminary findings suggest that this method may detect metabolic encephalopathies in the elderly. The study demonstrates the potential value of this approach and suggests the need for further research. PMID:2282132

Katz, I R; Sussman, N M; Mossey, J; Muenz, L; Harner, R N; Jethanandani, V

1990-01-01

176

Evaluation of EEG features in decoding individual finger movements from one hand.  

PubMed

With the advancements in modern signal processing techniques, the field of brain-computer interface (BCI) is progressing fast towards noninvasiveness. One challenge still impeding these developments is the limited number of features, especially movement-related features, available to generate control signals for noninvasive BCIs. A few recent studies investigated several movement-related features, such as spectral features in electrocorticography (ECoG) data obtained through a spectral principal component analysis (PCA) and direct use of EEG temporal data, and demonstrated the decoding of individual fingers. The present paper evaluated multiple movement-related features under the same task, that is, discriminating individual fingers from one hand using noninvasive EEG. The present results demonstrate the existence of a broadband feature in EEG to discriminate individual fingers, which has only been identified previously in ECoG. It further shows that multiple spectral features obtained from the spectral PCA yield an average decoding accuracy of 45.2%, which is significantly higher than the guess level (P < 0.05) and other features investigated (P < 0.05), including EEG spectral power changes in alpha and beta bands and EEG temporal data. The decoding of individual fingers using noninvasive EEG is promising to improve number of features for control, which can facilitate the development of noninvasive BCI applications with rich complexity. PMID:23710250

Xiao, Ran; Ding, Lei

2013-01-01

177

Estimation of neurophysiological parameters from the waking EEG using a biophysical model of brain dynamics.  

PubMed

This paper presents the results from using electroencephalographic (EEG) data to estimate the values of key neurophysiological parameters using a detailed biophysical model of brain activity. The model incorporates spatial and temporal aspects of cortical function including axonal transmission delays, synapto-dendritic rates, range-dependent connectivities, excitatory and inhibitory neural populations, and intrathalamic, intracortical, corticocortical and corticothalamic pathways. Parameter estimates were obtained by fitting the model's theoretical spectrum to EEG spectra from each of 100 healthy human subjects. Statistical analysis was used to infer significant parameter variations occurring between eyes-closed and eyes-open states, and a correlation matrix was used to investigate links between the parameter variations and traditional measures of quantitative EEG (qEEG). Accurate fits to all experimental spectra were observed, and both inter-subject and between-state variability were accounted for by the variance in the fitted biophysical parameters, which were in turn consistent with known independent experimental and theoretical estimates. These values thus provide physiological information regarding the state. transitions (eyes-closed vs. eyes-open) and phenomena including cortical idling and alpha desynchronization. The parameters are also consistent with traditional qEEG, but are more informative, since they provide links to underlying physiological processes. To our knowledge, this is the first study where a detailed biophysical model of the brain is used to estimate neurophysiological parameters underlying the transitions in a broad range (0.25-50 Hz) of EEG spectra obtained from a large set of human data. PMID:15501472

Rowe, Donald L; Robinson, Peter A; Rennie, Christopher J

2004-12-01

178

High gamma mapping using EEG  

PubMed Central

High gamma (HG) power changes during motor activity, especially at frequencies above 70 Hz, play an important role in functional cortical mapping and as control signals for BCI (brain computer interface) applications. Most studies of HG activity have used ECoG (electrocorticography) which provides high-quality spatially localized signals, but is an invasive method. Recent studies have shown that non-invasive modalities such as EEG and MEG can also detect task related HG power changes. We show here that a 27 channel EEG (electroencephalography) montage provides high-quality spatially localized signals non-invasively for HG frequencies ranging from 83 to 101 Hz. We used a generic head model, a weighted minimum norm least squares (MNLS) inverse method, and a self-paced finger movement paradigm. The use of an inverse method enables us to map the EEG onto a generic cortex model. We find the HG activity during the task to be well localized in the contralateral motor area. We find HG power increases prior to finger movement, with average latencies of 462 ms and 82 ms before EMG (electromyogram) onset. We also find significant phase-locking between contra- and ipsilateral motor areas over a similar HG frequency range; here the synchronization onset precedes the EMG by 400 ms. We also compare our results to ECoG data from a similar paradigm and find EEG mapping and ECoG in good agreement. Our findings demonstrate that mapped EEG provides information on two important parameters for functional mapping and BCI which are usually only found in HG of ECoG signals: spatially localized power increases and bihemispheric phase-locking.

Darvas, F.; Scherer, R.; Ojemann, J. G.; Rao, R.P.; Miller, K.J.; Sorensen, L. B.

2009-01-01

179

High gamma mapping using EEG.  

PubMed

High gamma (HG) power changes during motor activity, especially at frequencies above 70 Hz, play an important role in functional cortical mapping and as control signals for BCI (brain-computer interface) applications. Most studies of HG activity have used ECoG (electrocorticography) which provides high-quality spatially localized signals, but is an invasive method. Recent studies have shown that non-invasive modalities such as EEG and MEG can also detect task-related HG power changes. We show here that a 27 channel EEG (electroencephalography) montage provides high-quality spatially localized signals non-invasively for HG frequencies ranging from 83 to 101 Hz. We used a generic head model, a weighted minimum norm least squares (MNLS) inverse method, and a self-paced finger movement paradigm. The use of an inverse method enables us to map the EEG onto a generic cortex model. We find the HG activity during the task to be well localized in the contralateral motor area. We find HG power increases prior to finger movement, with average latencies of 462 ms and 82 ms before EMG (electromyogram) onset. We also find significant phase-locking between contra- and ipsilateral motor areas over a similar HG frequency range; here the synchronization onset precedes the EMG by 400 ms. We also compare our results to ECoG data from a similar paradigm and find EEG mapping and ECoG in good agreement. Our findings demonstrate that mapped EEG provides information on two important parameters for functional mapping and BCI which are usually only found in HG of ECoG signals: spatially localized power increases and bihemispheric phase-locking. PMID:19715762

Darvas, F; Scherer, R; Ojemann, J G; Rao, R P; Miller, K J; Sorensen, L B

2010-01-01

180

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.

Vakalopoulos, Costa

2014-01-01

181

Noninvasive epileptic seizure localization from stochastic behavior of short duration interictal high density scalp EEG data.  

PubMed

The stochastic behavior of the phase synchronization index (SI) in different EEG bands was examined for noninvasive localization of the epileptogenic areas from the short duration (30-60 s), seizure-free and spike-free high density (256 channel) scalp EEG data. We also examined the cross-frequency and cross-electrode coupling in different EEG bands. EEG data of four subjects was used. The seizure areas were localized with subdural recordings with an 8×8 grid electrode array. It was found that the stochastic behavior of the SI in low gamma band (30-50 Hz) was higher in epileptogenic areas. The beta (12-30 Hz) band also showed similar tendencies. The stochastic behavior in theta (3-7 Hz) band was depressed in the seizure area while it was widespread in large areas over the scalp in the alpha (7-12 Hz) band. The stochastic behavior of the cross-frequency and cross-electrode couplings in theta-gamma, alpha-gamma and beta-gamma bands were decreased in the seizure areas for all four subjects. These findings suggest that it is possible to localize the epileptogenic areas from the short duration seizure-free and spike-free high density scalp EEG data. PMID:21644027

Ramon, Ceon; Holmes, Mark D

2012-01-01

182

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

PubMed Central

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

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

2011-01-01

183

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

PubMed

Computer-aided diagnosis of neural diseases from EEG signals (or other physiological signals that can be treated as time series, e.g., MEG) is an emerging field that has gained much attention in past years. Extracting features is a key component in the analysis of EEG signals. In our previous works, we have implemented many EEG feature extraction functions in the Python programming language. As Python is gaining more ground in scientific computing, an open source Python module for extracting EEG features has the potential to save much time for computational neuroscientists. In this paper, we introduce PyEEG, an open source Python module for EEG feature extraction. PMID:21512582

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

2011-01-01

184

EEG changes accompanying learned regulation of 12Hz EEG activity  

Microsoft Academic Search

We analyzed 15 sessions of 64-channel electroencephalographic (EEG) data recorded from a highly trained subject during sessions in which he attempted to regulate power at 12 Hz over his left- and right-central scalp to control the altitude of a cursor moving toward target boxes placed at the top-, middle-, or bottom-right of a computer screen. We used infomax independent component

Arnaud Delorme; Scott Makeig

2003-01-01

185

The effects of Dalmane /flurazepam hydrochloride/ on human EEG characteristics.  

NASA Technical Reports Server (NTRS)

Evaluation of the changes in the waking EEGs of six healthy male subjects who received 30 mg daily oral doses of flurazepam hydrochloride for two weeks. A placebo was then substituted for flurazepam for another two weeks. An increase in beta activity with a maximum in fronto-central leads was observed during the test period. A small increase in the mean wavelength of the alpha and theta activities in the central-occipital derivations was also apparent in the subjects during the period.

Frost, J. D., Jr.; Carrie, J. R. G.; Borda, R. P.; Kellaway, P.

1973-01-01

186

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.

Britz, Juliane; Diaz Hernandez, Laura; Ro, Tony; Michel, Christoph M.

2014-01-01

187

EEG-microstate dependent emergence of perceptual awareness.  

PubMed

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

188

Human cortical electroencephalography (EEG) rhythms during the observation of simple aimless movements: a high-resolution EEG study.  

PubMed

In the present high-resolution electroencephalographic (EEG) study, we computed event-related desynchronization and synchronization (ERD/ERS) of alpha (about 10 Hz) and beta (about 20 Hz) rhythms in association with the execution (with visual feedback) and observation of brisk unilateral right and left aimless finger movements. A first scope was to test the topographical "functional equivalence" of cortical rhythmicity related to movement execution and observation, which would represent an ideal cortical observation/execution matching system. A second scope was to evaluate the hypothesis of a left or right hemisphere prevalence of the cortical rhythmicity related to the movement observation compared to the movement execution. EEG (128 electrodes) was recorded in 10 healthy right-handed volunteers. Surface Laplacian estimation spatially enhanced EEG data over a MRI-constraint head model. Under both conditions, ERD peaked during the movement execution or observation and was replaced by a ERS "rebound" or "recovery," which peaked during the postevent period. Topographical results are in favor of a "functional equivalence" (i.e., similar ERD/ERS values in magnitude and timing) of alpha and beta rhythmicity in central scalp regions overlying premotor/primary sensorimotor cortex. On the contrary, the functional equivalence of alpha rhythmicity was negligible (i.e., different ERD/ERS values in magnitude and timing) in parietal-occipital scalp regions overlying posterior parietal and parieto-occipital cortex, which could be the neural substrate to distinguish among the own motor intensions and others' aimless movements (i.e., visuomotor transformation integrated with sensorimotor, postural, and kinematics representations). Finally, the pattern of hemispherical cortical rhythmicity did not support a "simple concentration" of movement observation functions in the left or right hemisphere. PMID:12377134

Babiloni, Claudio; Babiloni, Fabio; Carducci, Filippo; Cincotti, Febo; Cocozza, Guido; Del Percio, Claudio; Moretti, Davide V; Rossini, Paolo Maria

2002-10-01

189

The creative brain: investigation of brain activity during creative problem solving by means of EEG and FMRI.  

PubMed

Cortical activity in the EEG alpha band has proven to be particularly sensitive to creativity-related demands, but its functional meaning in the context of creative cognition has not been clarified yet. Specifically, increases in alpha activity (i.e., alpha synchronisation) in response to creative thinking can be interpreted in different ways: As a functional correlate of cortical idling, as a sign of internal top-down activity or, more specifically, as selective inhibition of brain regions. We measured brain activity during creative thinking in two studies employing different neurophysiological measurement methods (EEG and fMRI). In both studies, participants worked on four verbal tasks differentially drawing on creative idea generation. The EEG study revealed that the generation of original ideas was associated with alpha synchronisation in frontal brain regions and with a diffuse and widespread pattern of alpha synchronisation over parietal cortical regions. The fMRI study revealed that task performance was associated with strong activation in frontal regions of the left hemisphere. In addition, we found task-specific effects in parietotemporal brain areas. The findings suggest that EEG alpha band synchronisation during creative thinking can be interpreted as a sign of active cognitive processes rather than cortical idling. PMID:18266217

Fink, Andreas; Grabner, Roland H; Benedek, Mathias; Reishofer, Gernot; Hauswirth, Verena; Fally, Maria; Neuper, Christa; Ebner, Franz; Neubauer, Aljoscha C

2009-03-01

190

Mahalanobis Distance-Based Classifiers are Able to Recognize EEG patterns by Using Few EEG Electrodes.  

National Technical Information Service (NTIS)

In this paper, we explore the use of quadratic classifiers based on Mahalanobis distance to detect EEG patterns from a reduced set of recording electrodes. Such classifiers used the diagonal and full covariance matrix of EEG spectral features extracted fr...

F. Babiloni L. Bianchi F. Semeraro J. Millan J. Mourinyo

2001-01-01

191

Effets des radiofréquences sur le système nerveux central chez l?homme : EEG, sommeil, cognition, vascularisation  

NASA Astrophysics Data System (ADS)

Most of clinical studies on radiofrequency electromagnetic fields (RF) were directed at mobile phone-related exposures, usually at the level of the head, at their effect on some physiological functions including sleep, brain electrical activity (EEG), cognitive processes, brain vascularisation, and more generally on the cardiovascular and endocrine systems. They were frequently carried out on healthy adults. Effects on the amplitude of EEG alpha waves, mainly during sleep, look reproducible. It would however be important to define more precisely whether and how the absence of electromagnetic disturbance between RF exposure and the recording systems is checked. No consensus arises about cognitive effects. Some effects on cerebral vascularisation need complementary work.

Ghosn, Rania; Villégier, Anne-Sophie; Selmaoui, Brahim; Thuróczy, Georges; de Sèze, René

2013-05-01

192

[Biologic artifacts in quantitative EEG].  

PubMed

We studied the influence of five biologic artifacts sources on quantitative EEG (blinking, forced eyes closure, forced jaw closure, tongue movements and pursuit eyes movements) through both visual and spectral analysis, with the purpose of verifying how do these artifacts can be seen in a cartographic way. We found that the spectrums potentials showed the same topographic display that was found through visual analysis. Visual analysis was superior than the quantitative evaluation to recognise the artifacts, as the former preserved the morphological display of the paroxysms. However it is important know how do the potentials are represented in quantitative maps, so that they can be identified as artifacts and not as pathologic EEG activity. PMID:16791367

Anghinah, Renato; Basile, Luis I; Schmidt, Magali T; Sameshima, Koichi; Gattaz, Wagner Farid

2006-06-01

193

Fast wavelet transformation of EEG.  

PubMed

Wavelet transforms offer certain advantages over Fourier transform techniques for the analysis of EEG. Recent work has demonstrated the applicability of wavelets for both spike and seizure detection, but the computational demands have been excessive. We compare the quality of feature extraction of continuous wavelet transforms using standard numerical techniques, with more rapid algorithms utilizing both polynomial splines and multiresolution frameworks. We further contrast the difference between filtering with and without the use of surrogate data to model background noise, demonstrate the preservation of feature extraction with critical versus redundant sampling, and perform the analyses with wavelets of different shape. Comparison is made with windowed Fourier transforms, similarly filtered, at different data window lengths. We here report a dramatic reduction in computational time required to perform this analysis, without compromising the accuracy of feature extraction. It now appears technically feasible to filter and decompose EEG using wavelet transforms in real time with ordinary microprocessors. PMID:7529683

Schiff, S J; Aldroubi, A; Unser, M; Sato, S

1994-12-01

194

EEG correlates of virtual reality hypnosis.  

PubMed

The study investigated hypnosis-related electroencephalographic (EEG) coherence and power spectra changes in high and low hypnotizables (Stanford Hypnotic Clinical Scale) induced by a virtual reality hypnosis (VRH) induction system. In this study, the EEG from 17 participants (Mean age = 21.35, SD = 1.58) were compared based on their hypnotizability score. The EEG recording associated with a 2-minute, eyes-closed baseline state was compared to the EEG during a hypnosis-related state. This novel induction system was able to produce EEG findings consistent with previous hypnosis literature. Interactions of significance were found with EEG beta coherence. The high susceptibility group (n = 7) showed decreased coherence, while the low susceptibility group (n = 10) demonstrated an increase in coherence between medial frontal and lateral left prefrontal sites. Methodological and efficacy issues are discussed. PMID:19031235

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

2009-01-01

195

[Comparative EEG study in normal and autistic children].  

PubMed

The work represents the results of a comparative study of spectral power as well as averaged coherence in alpha, beta and gamma EEG bands in 5-to-7-year-old autistic and healthy boys in the state of rest and under cognitive load (mental calculation). The mean age of the examined children was 6 years 4 months. In both healthy and autistic children, there was a clear-cut baseline frontal-occipital gradient of the alpha activity. Performance of the cognitive task led to enhancement of spectral power in the alpha1 band and shifting its maximum to the left hemisphere, did not change the activity in the alpha2 band, and considerably increased the spectral power in the alpha3 band. In healthy children, the spectral power and average coherence of the fast rhythms increased in the central and frontal areas of the left hemisphere. The right-side dominance of the spectral power of the alpha band was revealed in autistic children both in the baseline and during cognitive task. The spectral power of the gamma band was higher in autistic children than in healthy children in the baseline. The cognitive task did not change this fast activity in autistic children. PMID:21434401

Lushchekina, E A; Podreznaia, E D; Lushchekin, V S; Strelets, V B

2010-01-01

196

High gamma mapping using EEG  

Microsoft Academic Search

High gamma (HG) power changes during motor activity, especially at frequencies above 70 Hz, play an important role in functional cortical mapping and as control signals for BCI (brain–computer interface) applications. Most studies of HG activity have used ECoG (electrocorticography) which provides high-quality spatially localized signals, but is an invasive method. Recent studies have shown that non-invasive modalities such as EEG

F. Darvas; R. Scherer; J. G. Ojemann; R. P. Rao; K. J. Miller; L. B. Sorensen

2010-01-01

197

EEG Signal Analysis: A Survey  

Microsoft Academic Search

The EEG (Electroencephalogram) signal indicates the electrical activity of the brain. They are highly random in nature and\\u000a may contain useful information about the brain state. However, it is very difficult to get useful information from these signals\\u000a directly in the time domain just by observing them. They are basically non-linear and nonstationary in nature. Hence, important\\u000a features can be

D. Puthankattil Subha; Paul K. Joseph; U. Rajendra Acharya; Choo Min Lim

2010-01-01

198

CARDIAC FIELD ARTIFACT IN SLEEP EEG  

Microsoft Academic Search

Estimates of the cardiac field artifact w ere obtained for each EEG\\/EOG channel of all-night sleep EEG\\/ECG recordings by heartbeat-related averaging of the EEG. These estimates - so-called templates - can be used for minimization of the art i- fact, e. g. by heartbeat-synchronized subtraction o f the template. The 3-dimensional nature of the car- diac field artifact is demonstrated

K. C. Harke; A. Schlögl; P. Anderer; G. Pfurtscheller

1999-01-01

199

Identification of Motor Imagery EEG Signal  

Microsoft Academic Search

To identify subjects by classifying motor imagery EEG signal. Second-order blind identification (SOBI), a blind source separation (BSS) algorithm was applied to preprocess EEG data in for higher signal-to-noise ratio. Subsequently, Fisher distance was used to extract features. Finally, classification of extracted features was performed by back-propagation neural networks. Four types motor imagery EEG of three subjects was classified respectively.

Dan Xiao; Jianfeng Hu

2010-01-01

200

Classification of Long-Term EEG Recordings  

Microsoft Academic Search

\\u000a Computer assisted processing of long-term EEG recordings is gaining a growing importance. To simplify the work of a physician,\\u000a that must visually evaluate long recordings, we present a method for automatic processing of EEG based on learning classifier.\\u000a This method supports the automatic search of long-term EEG recording and detection of graphoelements – signal parts with characteristic\\u000a shape and defined

Karel Kosar; Lenka Lhotská; Vladimir Krajca

2004-01-01

201

Fundamentals of EEG Methodology in Concussion Research  

Microsoft Academic Search

The EEG in humans was first demonstrated by Hans Berger in the 1920s. His initial speculation that EEG could give us insight\\u000a into physiological and cognitive processes has been validated in a variety of situations ranging from sleep to wakefulness\\u000a as well as physiological concomitants of a variety of cognitive events. The current chapter will review basic EEG processes\\u000a and

William J. Ray; Semyon Slobounov

202

Independent EEG Sources Are Dipolar  

PubMed Central

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

Delorme, Arnaud; Palmer, Jason; Onton, Julie; Oostenveld, Robert; Makeig, Scott

2012-01-01

203

Electroencephalographic(EEG)-based communication: EEG control versus system performance in humans  

Microsoft Academic Search

People can learn to control electroencephalographic (EEG) sensorimotor rhythm amplitude so as to move a cursor to select among choices on a computer screen. We explored the dependence of system performance on EEG control. Users moved the cursor to reach a target at one of four possible locations. EEG control was measured as the correlation (r2) between rhythm amplitude and

Hesham Sheikh; Dennis J. McFarland; William A. Sarnacki; Jonathan R. Wolpaw

2003-01-01

204

Mahalanobis distance-based classifiers are able to recognize EEG patterns by using few EEG electrodes  

Microsoft Academic Search

We explore the use of quadratic classifiers based on Mahalanobis distance to detect EEG patterns from a reduced set of recording electrodes. Such classifiers used the diagonal and full covariance matrix of EEG spectral features extracted from EEG data. Such data were recorded from a group of 8 healthy subjects with 4 electrodes, placed in C3, P3, C4, P4 position

Fabio Babiloni; Luigi Bianchi; Francesco Semeraro; J. del R Millan; J. Mourino; A. Cattini; S. Salinari; M. G. Marciani; F. Cincotti

2001-01-01

205

Residual brain dysfunction observed one year post-mild traumatic brain injury: Combined EEG and balance study  

PubMed Central

Objectives There is still considerable debate and controversy about whether EEG can be used as a robust clinical tool for assessment of mild traumatic brain injury (MTBI). Nonhomogeneous subject populations, inaccurate assessment of severity of brain injury, time since injury when EEG testing was performed, the lack of EEG research conducted serially and in conjunction with other behavioral measures as injury evolves over time may contribute to the existing controversies. In this study, we implemented a concussion assessment protocol combining a series of EEG and balance measures throughout one year post-injury to document the efficacy of EEG and balance measures as relate to differential recovery of patients suffering from MTBI. Methods Three hundred and eighty subjects at risk for MTBI were initially recruited for baseline testing. Forty nine from this initial subjects pool subsequently suffered a single episode of concussive blow and were tested on day 7, 15, 30 days, 6 months and 12 months post-injury. EEGs were recorded while sitting, standing on the force plate and then on a foam base of support with eyes open/closed conditions. EEG alpha power (8–12 Hz) and its percent suppression from sitting to standing postures were computed. The center of pressure (COP) measures were obtained from the force platform and analyzed for eyes open and eyes closed conditions. Results Percent alpha power suppression from sitting to standing postural conditions significantly increased in MTBI subjects shortly after the injury (p < 0.01). Percent alpha power suppression significantly correlated with increased area of COP during standing posture with eye closed (r2 = 0.53, p < 0.01). The magnitude of alpha power suppression predicted the rate of recovery of this measure in sub-acute and chronic phases of injury (r2 = 0.609, p < 0.01). Finally, 85% of MTBI subjects who showed more than 20% of alpha power suppression in the acute phase of injury did not return to pre-injury status up to 12 months post-injury. Conclusions The efficacy of serially implemented EEG measures in conjunction with balance assessment over the course of MTBI evolution to document residual cerebral dysfunction was demonstrated. Specifically, alteration of EEG alpha power dynamics in conjunction with balance data in the acute phase of injury with respect to baseline measures may predict the rate of recovery from a single concussive blow. Significance Neurophysiological measures are excellent tools to assess the status and prognosis of patients with MTBI.

Slobounov, Semyon; Sebastianelli, Wayne; Hallett, Mark

2012-01-01

206

The effects of 10 Hz repetitive transcranial magnetic stimulation on resting EEG power spectrum in healthy subjects.  

PubMed

10 Hz rTMS over the left prefrontal cortex may be useful in the treatment of depressive disorders. However, the effects of 10 Hz rTMS applied in potentially effective doses on electroencephalographic activity are not well studied. Using EEG, we aimed to investigate the neurobiological effects of the 10 Hz rTMS set of parameters currently used for depression treatment in a sample of healthy subjects. In 18 healthy subjects, either 10 Hz real rTMS or sham stimulation were given in a crossover design. Real rTMS stimulation was carried out with an intensity of 110% of motor threshold (MT) over the left dorsolateral prefrontal cortex. For the sham condition, the coil was angled over a parietotemporal position and the intensity was reduced to 90% of MT. EEG recordings were taken before and after a single rTMS session. EEG power spectrum was extracted using the complex demodulation method and changes in power were evaluated statistically. Real 10 Hz rTMS induced an overall increase in delta power. This increase prevailed throughout the sample, whereas effects on the power of the alpha, beta and theta EEG bands were highly variable. Sham stimulation had no substantial effects on the EEG power spectrum. Furthermore, no changes in EEG asymmetry were detected. Real 10 Hz rTMS applied at 2000 stimuli and 110% intensity may induce significant changes in resting EEG in healthy subjects. PMID:17478041

Griskova, Inga; Ruksenas, Osvaldas; Dapsys, Kastytis; Herpertz, Sabine; Höppner, Jacqueline

2007-05-29

207

EEG Evolution in Sturge-Weber Syndrome  

PubMed Central

SUMMARY The EEG in Sturge-Weber syndrome (SWS) was theorized over 50 years ago as changing over time from normality to focal asymmetry to lastly epileptiform. We sought to validate these findings in a larger cohort today. Children with confirmed SWS and routine EEG at our center were evaluated retrospectively. An EEG score (0–3) was created and linked to patient current age, overall neurologic function, and seizure frequency. Eighty-one EEGs from 44 patients with SWS (mean age 2.0 years (range: 0.2 – 37.9 years) were evaluated and assigned an EEG score. The mean age for patients with an EEG score of 0–1 (normal or focal slowing) was 3.2 years (SEM 0.6), whereas those with an EEG score of 2–3 (focal sharp waves or frequent spike-wave bursts) was 8.7 years (SEM 1.7) (p=0.006). There was no correlation between the EEG score and either the SWS overall neuroscore or seizure subscore (measuring frequency). The EEG in patients with SWS does appear to evolve over time, becoming more abnormal with more frequent epileptiform activity, as suspected in smaller studies decades ago. This progressive change, however, did not correlate with the child’s neurologic function or seizure frequency.

Kossoff, Eric H.; Bachur, Cathy; Quain, Angela M.; Ewen, Joshua B.; Comi, Anne M.

2014-01-01

208

Ellen R. Grass Lecture: extraordinary EEG.  

PubMed

The electroencephalogram (EEG) is a unique measure of the electrical function of the brain. Cerebral sources of EEG potentials expressed by the human brain have been recorded on the surface of the scalp for almost 100 years. With the advances in digital technology, present day EEG has evolved to include specialized techniques that offer new capabilities never realized before. Refined intracranial recording techniques and multi-channel systems now permit access to regions of the brain that have previously been off limits to conventional EEG recording. Extraordinary biorhythms beyond 1 to 35 Hz that have been typically used in routine EEG are now exploring extreme bandwidths that may disclose epileptogenic regions and their yield causative networks involved in generating seizures. These spectral frequencies ranging from infraslow activity to high frequency oscillations have far reaching implications for people with uncontrolled seizures. Micro-EEG recordings are now shedding light on electrophysiological recordings of single columns of neuronal activity in clinical research expanding our understanding of epilepsy to the cellular level. Beyond the routine application of EEG analyzed for clinical use, special EEG techniques now provide a window to reveal detailed information about the seizure onset zone in patients with epilepsy, as well as advance our understanding of the functional processes of the brain itself. These breakthroughs will allow EEG-based treatment alternatives. PMID:24783746

Tatum, William O

2014-03-01

209

Effects of Ayahuasca on the human EEG.  

PubMed

EEG data were recorded under field conditions from 11 members of the Santo Daime Doctrine, a Brazilian shamanistic religion, before and after ingesting the psychoactive alkaloid preparation, ayahuasca, or daime, as they term it. Post-ingestion, we observed increases in power in the 36-44 Hz frequency band ("40 Hz") from the left occipital-temporal-parietal scalp electrodes in the eyes-closed condition, which extended to most of the posterior scalp in the eyes-open condition. The results are consistent with many reports that ayahuasca intensifies visual imagery. These results are discussed in terms of a thalamocortical model of the role of 40 Hz activity in brain function and conscious experience. We also noted tendencies toward decreases in the power of slow (theta and alpha) brain rhythms, and increases in the 14-30 Hz beta band, in accord with studies reported 30 years ago with other consciousness-altering compounds. Analysis of four ayahuasca samples yielded an average composition per ingested dose (75 ml) of 55.6 mg harmine, 43.9 mg tetrahydroharmine, 41.3 mg N,N-dimethyltryptamine (DMT), 4.6 mg harmaline, and 3.1 mg harmol. The DMT appeared to be of sufficient concentration to promote psychoactive effects, while the ?-carbolines functioned to supply MAO inhibitors necessary to prevent degradation of DMT and to maintain its oral activity. PMID:23195759

Don, N S; McDonough, B E; Moura, G; Warren, C A; Kawanishi, K; Tomita, H; Tachibana, Y; Böhlke, M; Farnsworth, N R

1998-04-01

210

Estimating brain load from the EEG.  

PubMed

Modern work requires cognitively demanding multitasking and the need for sustained vigilance, which may result in work-related stress and may increase the possibility of human error. Objective methods for estimating cognitive overload and mental fatigue of the brain on-line, during work performance, are needed. We present a two-channel electroencephalography (EEG)-based index, theta Fz/alpha Pz ratio, potentially implementable into a compact wearable device. The index reacts to both acute external and cumulative internal load. The index increased with the number of tasks to be performed concurrently (p = 0.004) and with increased time awake, both after normal sleep (p = 0.002) and sleep restriction (p = 0.004). Moreover, the increase of the index was more pronounced in the afternoon after sleep restriction (p = 0.006). As a measure of brain state and its dynamics, the index can be considered equivalent to the heartbeat, an indicator of the cardiovascular state, thus inspiring the name "brainbeat". PMID:19618092

Holm, Anu; Lukander, Kristian; Korpela, Jussi; Sallinen, Mikael; Müller, Kiti M I

2009-01-01

211

The neurobiology of the EEG biomarker as a predictor of treatment response in depression.  

PubMed

The management of depression remains a constant challenge in clinical practice. This is largely due to the fact that initial treatments frequently do not lead to remission and recovery. The current treatment approach involves lengthy trial-and-error periods. It would be beneficial to have early reliable predictors to determine whether patients will respond to treatment or not. Electroencephalography (EEG) derived biomarkers namely change in the activity of EEG frequency bands, hemispheric alpha asymmetry, theta cordance, the antidepressant treatment response index (ATR) and evoked potentials have all been shown to predict response to a variety of antidepressant medications. However, the neurobiology in support of this association has been largely unexplored. In this review, we discuss biological mechanisms for each EEG derived biomarker predictive of treatment response. Validating such biomarkers will not only greatly aid clinicians in selecting antidepressant treatment for individual patients but will also provide a critical step in drug discovery. PMID:22569197

Baskaran, Anusha; Milev, Roumen; McIntyre, Roger S

2012-09-01

212

Acquired somatic ATRX mutations in myelodysplastic syndrome associated with alpha thalassemia (ATMDS) convey a more severe hematologic phenotype than germline ATRX mutations.  

PubMed

Acquired somatic mutations in ATRX, an X-linked gene encoding a chromatin-associated protein, were recently identified in 4 patients with the rare subtype of myelodysplastic syndrome (MDS) associated with thalassemia (ATMDS). Here we describe a series of novel point mutations in ATRX detected in archival DNA samples from marrow and/or blood of patients with ATMDS by use of denaturing high-performance liquid chromatography (DHPLC), a technique sensitive to low-level mosaicism. Two of the new mutations result in changes in amino acids altered in previously described pedigrees with germ line ATRX mutations (ATR-X syndrome), but the hematologic abnormalities were much more severe in the patients with ATMDS than in the corresponding constitutional cases. In one ATMDS case where DNA samples from several time points were available, the proportion of ATRX-mutant subclones correlated with changes in the amount of hemoglobin H. This study strengthens the link between acquired, somatic ATRX mutations and ATMDS, illustrates how molecular defects associated with MDS and other hematologic malignancies masked by somatic mosaicism may be detected by DHPLC, and shows that additional factors increase the severity of the hematologic phenotype of ATRX mutations in ATMDS. PMID:14592816

Steensma, David P; Higgs, Douglas R; Fisher, Chris A; Gibbons, Richard J

2004-03-15

213

Preterm EEG: A Multimodal Neurophysiological Protocol  

PubMed Central

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.

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

2012-01-01

214

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

215

TNFalpha up-regulates SLUG via the NF-kappaB/HIF1alpha axis, which imparts breast cancer cells with a stem cell-like phenotype  

PubMed Central

Extracellular and intracellular mediators of inflammation, such as Tumor Necrosis Factor alpha (TNF?) and NF-kappaB (NF-?B), play major roles in breast cancer pathogenesis, progression and relapse. SLUG, a mediator of the epithelial-mesenchymal transition process, is over-expressed in CD44+/CD24? tumor initiating breast cancer cells and in basal-like carcinoma, a subtype of aggressive breast cancer endowed with a stem cell-like gene expression profile. Cancer stem cells also over-express members of the pro-inflammatory NF-?B network, but their functional relationship with SLUG expression in breast cancer cells remains unclear. Here, we show that TNF? treatment of human breast cancer cells up-regulates SLUG with a dependency on canonical NF-?B/HIF1? signaling, which is strongly enhanced by p53 inactivation. Moreover, SLUG up-regulation engenders breast cancer cells with stem cell-like properties including enhanced expression of CD44 and Jagged-1 in conjunction with ER? down-regulation, growth as mammospheres and extracellular matrix invasiveness. Our results reveal a molecular mechanism whereby TNF?, a major pro-inflammatory cytokine, imparts breast cancer cells with stem cell-like features, which are connected to increased tumor aggressiveness.

Storci, Gianluca; Sansone, Pasquale; Mari, Sara; D'Uva, Gabriele; Tavolari, Simona; Guarnieri, Tiziana; Taffurelli, Mario; Ceccarelli, Claudio; Santini, Donatella; Chieco, Pasquale; Marcu, Kenneth B.; Bonafe, Massimiliano

2010-01-01

216

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.

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

2013-01-01

217

Segregation of the thalamic alpha rhythms from cortical alpha activity using the Savit-Green S-statistic and estimated correlation dimension.  

PubMed

The large-amplitude, occipital alpha rhythm of the human electroencephalogram (EEG) is associated in normal subjects with a state of relaxed wakefulness. We analyzed resting eyes-open and eyes-closed human EEG data using three measures: power in the 8-12-Hz alpha frequency band, estimated correlation dimension (D2), and the Savit-Green S-statistic. At occipital loci, two groups of points were evident in the scatterplot of S vs. estimated D2. Group A was of higher dimension and consisted of predominantly eyes-open records. Group B was of lower dimension and consisted of more eyes-closed than eyes-open records. Furthermore, Group B had a broad range of alpha power, with alpha power being negatively correlated with estimated D2 (higher alpha power associated with lower dynamical complexity). In contrast, Group A had a very small range of low alpha power, and was positively correlated with estimated D2 (higher alpha power associated with increased dynamical complexity). Our results indicate that Group B EEG (the alpha rhythm) and Group A EEG (EEG containing 'other' alpha activity) have fundamentally different dynamical properties. PMID:9203008

Pritchard, W S; Duke, D W

1997-06-01

218

Atypical EEG Power Correlates With Indiscriminately Friendly Behavior in Internationally Adopted Children  

PubMed Central

While effects of institutional care on behavioral development have been studied extensively, effects on neural systems underlying these socioemotional and attention deficits are only beginning to be examined. The current study assessed electroencephalogram (EEG) power in 18-month-old internationally adopted, post-institutionalized children (n = 37) and comparison groups of non-adopted children (n = 47) and children internationally adopted from foster care (n = 39). For their age, post-institutionalized children had an atypical EEG power distribution, with relative power concentrated in lower frequency bands compared to non-adopted children. Both internationally adopted groups had lower absolute alpha power than non-adopted children. EEG power was not related to growth at adoption or to global cognitive ability. Atypical EEG power distribution at 18 months predicted indiscriminate friendliness and poorer inhibitory control at 36 months. Both post-institutionalized and foster care children were more likely than non-adopted children to exhibit indiscriminate friendliness. Results are consistent with a cortical hypoactivation model of the effects of early deprivation on neural development and provide initial evidence associating this atypical EEG pattern with indiscriminate friendliness. Outcomes observed in the foster care children raise questions about the specificity of institutional rearing as a risk factor and emphasize the need for broader consideration of the effects of early deprivation and disruptions in care.

Tarullo, Amanda R.; Garvin, Melissa C.; Gunnar, Megan R.

2012-01-01

219

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

PubMed

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

2008-09-19

220

Characterizing Alzheimer's Disease Severity via Resting-Awake EEG Amplitude Modulation Analysis  

PubMed Central

Changes in electroencephalography (EEG) amplitude modulations have recently been linked with early-stage Alzheimer’s disease (AD). Existing tools available to perform such analysis (e.g., detrended fluctuation analysis), however, provide limited gains in discriminability power over traditional spectral based EEG analysis. In this paper, we explore the use of an innovative EEG amplitude modulation analysis technique based on spectro-temporal signal processing. More specifically, full-band EEG signals are first decomposed into the five well-known frequency bands and the envelopes are then extracted via a Hilbert transform. Each of the five envelopes are further decomposed into four so-called modulation bands, which were chosen to coincide with the delta, theta, alpha and beta frequency bands. Experiments on a resting-awake EEG dataset collected from 76 participants (27 healthy controls, 27 diagnosed with mild-AD, and 22 with moderate-AD) showed significant differences in amplitude modulations between the three groups. Most notably, i) delta modulation of the beta frequency band disappeared with an increase in disease severity (from mild to moderate AD), ii) delta modulation of the theta band appeared with an increase in severity, and iii) delta modulation of the beta frequency band showed to be a reliable discriminant feature between healthy controls and mild-AD patients. Taken together, it is hoped that the developed tool can be used to assist clinicians not only with early detection of Alzheimer’s disease, but also to monitor its progression.

Fraga, Francisco J.; Falk, Tiago H.; Kanda, Paulo A. M.; Anghinah, Renato

2013-01-01

221

Simultaneous recording of pupillary hippus and EEG  

Microsoft Academic Search

Pupillary hippus was observed and recorded in a man of 44 years, who had epileptic seizures, chronic alcoholism with liver disease and Primidon intoxication, during a period of unconsciousness of 24 h. During this time the simultaneous records of the EEG and pupillogram over a long period of time revealed that the basic EEG rhythm and hippus had the same

A. Mfiller-Jensen; R. Hagenah

1978-01-01

222

Microfiche data reduction for the EEG laboratory.  

PubMed

A convenient, low cost microfiche system for the random access, storage and retrieval of EEG data is described. Some of the more important advantages of microfilm in an EEG laboratory are: enormous data reductions; reduced operating costs; simplified records handling; improved communications between electroencephalographers; and access to an expanding number of inexpensive publications and reference materials. PMID:6851187

Gibbs, E L; Gibbs, T J

1983-04-01

223

EEG Analysis for Brainwave Balancing Index (BBI)  

Microsoft Academic Search

The purpose of this research is to establish the fundamental brainwave balancing index (BBI) using EEG signals. Brainwave signals from EEG were measured and analyzed using intelligent signal processing techniques and specific algorithm. Consequently, the signals were statistically correlated with established psychoanalysis techniques to produce BBI system. The result shows that the PSD analysis provides reliable BBI with 80% conformity.

Z. H. Murat; M. N. Taib; S. Lias; R. S. S. A. Kadir; N. Sulaiman; M. Mustafa

2010-01-01

224

Development of Brainwave Balancing Index Using EEG  

Microsoft Academic Search

In this research, Wireless EEG equipment via Bluetooth technology named g-Mobilab was used to measure the brainwave signals in the right and left frontal area of the brain. The recorded EEG signals were channelled into an automatic artifact removal analysis whereby signals above values of 100 micro-volts were removed by means of a program using Matlab. Consequently, Power Spectral Density

Zunairah Hj. Murat; Mohd Nasir Taib; Sahrim Lias; Ros Shilawani S. Abdul Kadir; Norizam Sulaiman; Zodie Mohd Hanafiah

2011-01-01

225

Eeg Changes in Perceptual and Sensory Deprivation.  

National Technical Information Service (NTIS)

Observations on changes in the EEG produced by 7-14 days sensory and perceptual deprivation in healthy young adults have been explored and attempts made to correlate the EEG changes with other factors. Continuous exposure to unpatterned light and noise pr...

M. G. Saunders J. P. Zubek

1967-01-01

226

Estimating Alertness from the EEG Power Spectrum  

Microsoft Academic Search

In tasks requiring sustained attention, human alertness varies on a minute time scale. This can have seriousconsequences in occupations ranging from air traffic control to monitoring of nuclear power plants. Changesin the electroencephalographic (EEG) power spectrum accompany these fluctuations in the level of alertness,as assessed by measuring simultaneous changes in EEG and performance on an auditory monitoring task. Bycombining power

Tzyy-ping Jung; Scott Makeig; Magnus Stensmo; Terrence J. Sejnowski

1997-01-01

227

A full digital video EEG system  

Microsoft Academic Search

Presents a Digital Video Electroencephalogram (EEG) system which synchronizes the video and EEG signals and displays two data on the different monitor. Also this system stores all data on the extra capacity digital media simultaneously. In this system, video images from video camera are encoded to the MPEG-I structure data. The synchronization of two signals is accomplished by calculating video

Sae B. Kim; Yong H. Lee; Ju H. Kim; Sun I. Kim

1999-01-01

228

EEG topography recognition by neural networks  

Microsoft Academic Search

Electroencephalography (EEG) pattern-recognition studies were carried out using EEG topography (readiness potential, or RP, spatiotemporal patterns) generated the moment before voluntary movements of muscles. RPs generated prior to pronouncing syllables and controlling a joystick were studied by experiments and simulation. The spatiotemporal patterns of RPs were measured by multichannel surface electrodes pasted on the subject's scalp. Backpropagation neural networks were

A. Hiraiwa; K. Shimohara; Y. Tokunaga

1990-01-01

229

Phenotype-genotype characterization of alpha-thalassemia mental retardation syndrome due to isolated monosomy of 16p13.3.  

PubMed

An 8-year-old Caucasian girl presented with mild dysmorphic features and intellectual disability (ID) affecting multiple spheres. Dysmorphisms included a high forehead with up-slanting palpebral fissures, prominent nasal root and bridge, flattened maxilla, high-arched palate, and anterior frenulum. Structural brain anomalies included reduced periventricular white matter volume and thin corpus callosum. The presence of HbH bodies and her clinical presentation raised suspicion for autosomal alpha-thalassemia mental retardation syndrome (ATR-16). Whole-genome array analysis at 1 Mb resolution was performed, which revealed a sub-microscopic loss of 16p involving clones RP11-344L6 at 0.1 Mb, RP1-121I4 at 0.2 Mb and RP11-334D3 at 1 Mb. FISH confirmed deletion (del) of the terminal clone (RP1-121I4) on 16pter, which was de novo in origin. The more proximal clone RP11-334D3 (at 1 Mb) showed diminished FISH signal intensity on one of the homologues, suggesting that one breakpoint occurred within this clone. Quantitative PCR (qPCR) confirmed a de novo deletion encompassing SOX8 (at 0.97 Mb). ATR-16 is characterized by ID with mild, nonspecific dysmorphic features, and is associated with terminal del16p (MIM No. 141750). Cases of isolated monosomy for 16p are rarely described; such descriptions help to delineate the syndrome in the absence of confounding karyotypic anomalies. We describe detailed molecular cytogenetic and clinical findings relating to a subject with ATR-16. PMID:18076105

Gibson, William T; Harvard, Chansonette; Qiao, Ying; Somerville, Martin J; Lewis, M E Suzanne; Rajcan-Separovic, Evica

2008-01-15

230

Estimation of the propagation direction and spectral properties of the EEG signals registered during sevoflurane anaesthesia using Directed Transfer Function method  

NASA Astrophysics Data System (ADS)

The aim of this study was to estimate spectral properties and propagation of the EEG signals registered during sevoflurane anaesthesia between individual EEG recording channels. The intensities of activity flows were calculated for delta, theta, alpha and beta waves using the Directed Transfer Function integration procedure. It was found that delta waves played the dominant role in the EEG signal propagation during anesthesia and it was suggested that theta and alpha waves propagation could be related to the processes participating in the wakefulness control. Data obtained with DTF method were compared with data received from the analysis of cerebral blood flow with the use of PET in other laboratory. This study showed that analysis of the EEG signal propagation is useful for better understanding and thus safer induction of anaesthesia procedure.

Olejarczyk, Elzbieta; Kaminski, Maciej; Marciniak, Radoslaw; Byrczek, Tomasz; Stasiowski, Michal; Jalowiecki, Przemyslaw; Sobieszek, Aleksander; Zmyslowski, Wojciech

2011-01-01

231

Neural network based EEG denoising.  

PubMed

A novel filter is proposed by applying back propagation neural network (BPNN) ensemble where the noisy signal and the reference one are the same in a learning process. This neural network (NN) ensemble filter not only well reduces additive and multiplicative white noise inside signals, but also preserves signals' characteristics. It is proved that the reduction of noise using NN ensemble filter is better than the improved epsilon nonlinear filter and single NN filter while signal to noise ratio is smaller. The performance of the NN ensemble filter is demonstrated in computer simulations and actual electroencephalogram (EEG) signals processing. PMID:19162643

Chen, Yongjian; Akutagawa, Masatake; Katayama, Masato; Zhang, Qinyu; Kinouchi, Yohsuke

2008-01-01

232

Abnormal dynamics of EEG oscillations in schizophrenia patients on multiple time scales.  

PubMed

Neuronal oscillations reflect the activity of neuronal ensembles engaged in integrative cognition, and may serve as a functional measure for the cognitive impairment in schizophrenia. This study aims to reveal the abnormal amplitude dynamics of electroencephalogram (EEG) oscillations in schizophrenia patients on multiple time scales. EEGs were recorded from schizophrenia patients ( n = 19) and healthy controls ( n = 16) while they were at resting state with eyes closed, at resting state with eyes open, and at watching video. Detrended fluctuation analysis and measures of life-time and waiting-time were used to characterize the abnormal dynamics of EEG oscillations on both long (1-20 s) and short (?1 s) time scales. Abnormal dynamics of EEG oscillations in alpha and beta bands were observed. In particular, compared with healthy controls, schizophrenia patients have smaller DFA exponent (implying weaker long-range temporal correlation) in the left fronto-temporal area and smaller DFA exponent, smaller life-time (indicating shorter oscillation burst), and smaller waiting-time in the occipital area in beta band at resting state with eyes open. In addition, schizophrenia patients have larger DFA exponent, larger life-time, and larger waiting-time at some clustered channels in the temporo-parietal area in alpha band at watching video. The present results provide new insights for cognitive deficits and the underlying neuronal dysfunction in schizophrenia. PMID:24845286

Sun, Junfeng; Tang, Yingying; Lim, Kelvin O; Wang, Jijun; Tong, Shanbao; Li, Hui; He, Bin

2014-06-01

233

Neural Correlates of Action Observation and Execution in 14-Month-Old Infants: An Event-Related EEG Desynchronization Study  

ERIC Educational Resources Information Center

There is increasing interest in neurobiological methods for investigating the shared representation of action perception and production in early development. We explored the extent and regional specificity of EEG desynchronization in the infant alpha frequency range (6-9 Hz) during action observation and execution in 14-month-old infants.…

Marshall, Peter J.; Young, Thomas; Meltzoff, Andrew N.

2011-01-01

234

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

235

Bimodal BCI using simultaneously NIRS and EEG.  

PubMed

Although noninvasive brain-computer interfaces (BCI) based on electroencephalographic (EEG) signals have been studied increasingly over the recent decades, their performance is still limited in two important aspects. First, the difficulty of performing a reliable detection of BCI commands increases when EEG epoch length decreases, which makes high information transfer rates difficult to achieve. Second, the BCI system often misclassifies the EEG signals as commands, although the subject is not performing any task. In order to circumvent these limitations, the hemodynamic fluctuations in the brain during stimulation with steady-state visual evoked potentials (SSVEP) were measured using near-infrared spectroscopy (NIRS) simultaneously with EEG. BCI commands were estimated based on responses to a flickering checkerboard (ON-period). Furthermore, an "idle" command was generated from the signal recorded by the NIRS system when the checkerboard was not flickering (OFF-period). The joint use of EEG and NIRS was shown to improve the SSVEP classification. For 13 subjects, the relative improvement in error rates obtained by using the NIRS signal, for nine classes including the "idle" mode, ranged from 85% to 53 %, when the epoch length increase from 3 to 12 s. These results were obtained from only one EEG and one NIRS channel. The proposed bimodal NIRS-EEG approach, including detection of the idle mode, may make current BCI systems faster and more reliable. PMID:24658251

Tomita, Yohei; Vialatte, François-Benoît; Dreyfus, Gérard; Mitsukura, Yasue; Bakardjian, Hovagim; Cichocki, Andrzej

2014-04-01

236

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.

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

2014-01-01

237

Towards wireless emotional valence detection from EEG.  

PubMed

Intelligent affective computers can have many medical and non-medical applications. However today's affective computers are limited in scope by their transferability to other application environments or that they monitor only one aspect of physiological emotion expression. Here, the use of a wireless EEG system, which can be implemented in a body area network, is used to investigate the potential of monitoring emotional valence in EEG, for application in real-life situations. The results show 82% accuracy for automatic classification of positive, negative and neutral valence based on film clip viewing, using features containing information on both the frequency content of the EEG and how this changes over time. PMID:22254773

Brown, Lindsay; Grundlehner, Bernard; Penders, Julien

2011-01-01

238

Quantified EEG in different G situations  

NASA Astrophysics Data System (ADS)

The electrical activity of the brain (EEG) has been recorded during parabolic flights in trained astronauts and non trained volunteers as well. The Fast Fourier analysis of the EEG activity evidenced more asymmetry between the two brain hemispheres in the subjects who suffered from motion sickness than in the others. However, such a FFT classification does not lead to a discrimination between deterministic and stochastic events. Therefore, a first attempt was made to calculate the dimensionality of "chaotic attractors" in the EEG patterns as a function of the different g-epochs of one parabola. Very preliminary results are given here.

de Metz, K.; Quadens, O.; De Graeve, M.

239

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

240

Adrenocorticotropin-related modulation of the human EEG and individual variability  

Microsoft Academic Search

During a 6-h period in resting conditions, the blood concentrations at rest of cortisol, glucose and the adrenocorticotropic hormone (ACTH) varied spontaneously within physiological ranges in eight healthy male volunteers (24.5±1.7 years), without pulsatile changes, correlation among variables, or indications of stress response. The power of the 6.5–14.0 Hz physiological `alpha' rhythm of the electroencephalogram (EEG) proved inverted-U correlated with

Walter G Sannita; Alberto Loizzo; Sergio Garbarino; Diana Gesino; Simona Massimilla; Carla Ogliastro

1999-01-01

241

Oscillatory EEG Correlates of Arithmetic Strategies: A Training Study  

PubMed Central

There has been a long tradition of research on mathematics education showing that children and adults use different strategies to solve arithmetic problems. Neurophysiological studies have recently begun to investigate the brain correlates of these strategies. The existing body of data, however, reflect static end points of the learning process and do not provide information on how brain activity changes in response to training or intervention. In this study, we explicitly address this issue by training participants in using fact retrieval strategies. We also investigate whether brain activity related to arithmetic fact learning is domain-specific or whether this generalizes to other learning materials, such as the solution of figural-spatial problems. Twenty adult students were trained on sets of two-digit multiplication problems and figural-spatial problems. After the training, they were presented with the trained and untrained problems while their brain activity was recorded by means of electroencephalography (EEG). In both problem types, the training resulted in accuracies over 90% and significant decreases in solution times. Analyses of the oscillatory EEG data also revealed training effects across both problem types. Specifically, we observed training-related activity increases in the theta band (3–6?Hz) and decreases in the lower alpha band (8–10?Hz), especially over parietooccipital and parietal brain regions. These results provide the first evidence that a short-term fact retrieval training results in significant changes in oscillatory EEG activity. These findings further corroborate the role of the theta band in the retrieval of semantic information from memory and suggest that theta activity is sensitive to fact retrieval not only in mental arithmetic but also in other domains.

Grabner, Roland H.; De Smedt, Bert

2012-01-01

242

Oscillatory EEG correlates of arithmetic strategies: a training study.  

PubMed

There has been a long tradition of research on mathematics education showing that children and adults use different strategies to solve arithmetic problems. Neurophysiological studies have recently begun to investigate the brain correlates of these strategies. The existing body of data, however, reflect static end points of the learning process and do not provide information on how brain activity changes in response to training or intervention. In this study, we explicitly address this issue by training participants in using fact retrieval strategies. We also investigate whether brain activity related to arithmetic fact learning is domain-specific or whether this generalizes to other learning materials, such as the solution of figural-spatial problems. Twenty adult students were trained on sets of two-digit multiplication problems and figural-spatial problems. After the training, they were presented with the trained and untrained problems while their brain activity was recorded by means of electroencephalography (EEG). In both problem types, the training resulted in accuracies over 90% and significant decreases in solution times. Analyses of the oscillatory EEG data also revealed training effects across both problem types. Specifically, we observed training-related activity increases in the theta band (3-6?Hz) and decreases in the lower alpha band (8-10?Hz), especially over parietooccipital and parietal brain regions. These results provide the first evidence that a short-term fact retrieval training results in significant changes in oscillatory EEG activity. These findings further corroborate the role of the theta band in the retrieval of semantic information from memory and suggest that theta activity is sensitive to fact retrieval not only in mental arithmetic but also in other domains. PMID:23162495

Grabner, Roland H; De Smedt, Bert

2012-01-01

243

Genetic overlap between ADHD symptoms and EEG theta power.  

PubMed

Biological markers that are grounded in neuroscience may facilitate understanding of the pathophysiology of complex psychiatric disorders. One of the most consistent and robust neural abnormalities in attention deficit hyperactivity disorder (ADHD) is increased EEG power in the theta band at rest (4-8Hz). The present study used a twin design to estimate the extent of genetic overlap between increased theta power and risk for ADHD in order to validate theta power as a marker of genetic risk for ADHD. At rest, EEG was measured in 30 monozygotic and dizygotic adolescent twin pairs concordant or discordant for high ADHD symptom scores and 37 monozygotic and dizygotic control twin pairs with low ADHD symptom scores. Structural equation modelling was used to estimate the heritability of theta power and partition the genetic and environmental contributions to the overlap between ADHD and theta power. A significant phenotypic correlation between ADHD symptoms and elevated theta power was found. Theta power demonstrated moderate to high heritability estimates (0.77) and moderate genetic correlations with ADHD (0.35) suggesting shared genetic influences. Increased theta power is a candidate biological marker of genetic risk for ADHD, which warrants further investigation of the neurobiological mechanisms that underlie the genetic relationship. PMID:24752036

Tye, Charlotte; Rijsdijk, Fruhling; McLoughlin, Gráinne

2014-06-01

244

Anoxic-ischemic alpha coma: prognostic significance of the incomplete variant.  

PubMed

The prognostic significance of post-anoxic-ischemic alpha coma (AC) is controversial. We recorded somatosensory evoked potentials (SEPs) and performed serial electroencephalography (EEG) in a 60-year-old woman in coma after cardiac arrest. The first EEG was recorded after 48 hours (GCS=5; E1-V1-M3); brain-stem reflexes were preserved. The EEG pattern showed monotonous alpha frequencies (10-11 Hz) with posterior predominance; acoustic and noxious stimuli evoked EEG reactivity. Early cortical SEPs (72 h) were normal. On the fifth day (GCS=8; E4-V1-M3), the EEG alpha pattern was replaced by a diffuse delta activity; rhythmic theta changes appeared spontaneously or in response to stimuli. The patient regained consciousness on the tenth day and EEG showed posterior theta activity (6-7 c/s) partially reactive to stimuli. At the 6-month follow-up, cognitive evaluation showed mild dementia. Recent studies identified two forms of AC. Patients with complete AC have an outcome that is almost invariably poor. Conversely, incomplete AC (posteriorly accentuated alpha frequency, reactive and with SEPs mostly normal) reflects a less severe degree of anoxic-ischemic encephalopathy. The case we report should be classified, according to the SEPs and EEG features, as incomplete AC. The fact that the patient has regained consciousness, even if with residual cognitive impairment, confirms the need to distinguish this variant from complete AC. PMID:14767685

Fossi, S; Amantini, A; Grippo, A; Cossu, C; Boni, N; Pinto, F

2004-02-01

245

EEG power mapping, dipole source and coherence analysis in Chernobyl patients.  

PubMed

EEG power mapping, coherence analysis, source localization of epileptiform activity and psychoneurological investigations were performed in 100 patients (males, 25-45 years old, right-handed), who took part in the cleaning of the Chernobyl disaster in 1986-1987, and compared with a control group (healthy persons of the same age). Neuropsychological studies showed autonomic, endocrine, emotional and other disorders in all patients. About 70% of all patients had paroxysmal EEG activity and intermittent seizures sometimes associated with loss of consciousness. EEG power mapping showed higher than normal levels of alpha- and theta-bands power, mainly in the frontal and central areas in the one group of patients. In others, power was lower especially in alpha-band. Paroxysmal waves of alpha- and theta-bands had localization of dipole sources at deeper near midline levels, and as a rule with a shift to the right hemisphere. Paroxysmal beta-waves demonstrated sources of a diffuse character at a more basal level with a shift to the left hemisphere. Interhemispheric coherences had lower values in the frontal and higher in the central leads than in healthy persons. Intrahemispheric coherences were decreased in the left hemisphere and increased in the right, opposite to that in controls. PMID:8793126

Zhavoronkova, L A; Kholodova, N B; Zubovsky, G A; Gogitidze, N V; Koptelov, Y M

1995-01-01

246

Alzheimer's disease qEEG: spectral analysis versus coherence. Which is the best measurement?  

PubMed

There is evidence in electroencephalography that alpha, theta and delta band oscillations reflect cognitive and memory performances and that quantitative techniques can improve the electroencephalogram (EEG) sensitivity. This paper presents the results of comparative analysis of qEEG variables as reliable markers for Alzheimer's disease (AD). We compared the sensitivity and specificity between spectral analysis (spectA) and coherence (Coh) within the same group of AD patients. SpectA and Coh were calculated from EEGs of 40 patients with mild to moderate AD and 40 healthy elderly controls. The peak of spectA was smaller in the AD group than in controls. AD group showed predominance of slow spectA in theta and delta bands and a significant reduction of inter-hemispheric Coh for occipital alpha 2 and beta 1 and for frontal delta sub-band. ROC curve supported that alpha band spectA was more sensitive than coherence to differentiate controls from AD. PMID:22297870

Anghinah, Renato; Kanda, Paulo Afonso Medeiros; Lopes, Helder Frederico; Basile, Luis Fernando Hindi; Machado, Sérgio; Ribeiro, Pedro; Velasques, Bruna; Sameshima, Koichi; Takahashi, Daniel Yasumasa; Pinto, Lécio Figueira; Caramelli, Paulo; Nitrini, Ricardo

2011-12-01

247

Biofeedback as a placebo: Anxiety reduction facilitated by training in either suppression or enhancement of alpha brainwaves  

Microsoft Academic Search

Assessed the differential effects (on experiential reports of anxiety) of actual performance and perceived success at an EEG biofeedback task. 10 college students who were high in trait anxiety (MMPI, State-Trait Anxiety Inventory) underwent training in either the suppression of enhancement of EEG alpha activity with the expectation that success at their biofeedback task would result in reductions of chronic

William B. Plotkin; Kathleen M. Rice

1981-01-01

248

Event-related synchronization (ERS) in the alpha band — an electrophysiological correlate of cortical idling: A review  

Microsoft Academic Search

EEG desynchronization is a reliable correlate of excited neural structures or activated cortical areas. EEG synchronization within the alpha band may be an electrophysiological correlate of deactivated cortical areas. Such areas are not processing sensory information or motor output and can be considered to be in an idling state. One example of such an idling cortical area is the enhancement

G. Pfurtscheller; A. Stancák; Ch. Neuper

1996-01-01

249

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 ...

250

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

251

Projection versus prewhitening for EEG interference suppression.  

PubMed

Suppression of strong, spatially correlated background interference is a challenge associated with electroencephalography (EEG) source localization problems. The most common way of dealing with such interference is through the use of a prewhitening transformation based on an estimate of the covariance of the interference plus noise. This approach is based on strong assumptions regarding temporal stationarity of the data, which do not commonly hold in EEG applications. In addition, prewhitening cannot typically be implemented directly due to ill conditioning of the covariance matrix, and ad hoc regularization is often necessary. Using both simulation examples and experiments involving real EEG data with auditory evoked responses, we demonstrate that a straightforward interference projection method is significantly more robust than prewhitening for EEG source localization. PMID:22333979

Wu, Shun Chi; Swindlehurst, A Lee; Wang, Po T; Nenadic, Zoran

2012-05-01

252

Quantitative EEG investigations of genital exhibitionism  

Microsoft Academic Search

Forty-three male genital exhibitionists and 46 normal controls, all right handed, and matched for age, sex, and education, were studied with quantitative EEG during resting conditions, with eyes open and eyes closed, and during two cognitive tasks (Vocabulary subtest of the WAIS-R, oral word fluency), and during spatial cognitive processing (Block Design subtest of the WAIS-R). Results indicated that EEG

P. Flor-Henry; R. A. Lang; Z. J. Koles; R. R. Frenzel

1988-01-01

253

Genetic influences on bipolar EEG power spectra  

Microsoft Academic Search

The EEG bipolar power spectra provide more localization than spectral measures obtained from monopolar referencing strategies, and have been shown to be useful endophenotypes of psychiatric disorders such as alcoholism. We estimated the additive genetic heritability of resting bipolar EEG power spectra in a large sample of non-twin sibling pairs. The corresponding heritabilities ranged between 0.220 and 0.647 and were

Yongqiang Tang; David B. Chorlian; Madhavi Rangaswamy; Bernice Porjesz; Lance Bauer; Samuel Kuperman; Sean O'Connor; John Rohrbaugh; Marc Schuckit; Arthur Stimus; Henri Begleiter

2007-01-01

254

A wireless multichannel EEG recording platform  

Microsoft Academic Search

A wireless multichannel data acquisition system is being designed for ElectroEncephaloGraphy (EEG) recording. The system is based on a custom integrated circuit (ASIC) for signal conditioning, amplification and digitization and also on commercial components for RF transmission. It supports the RF transmission of a 32-channel EEG recording sampled at 1 kHz with a 12-bit resolution. The RF communication uses the

S. Filipe; G. Charvet; M. Foerster; J. Porcherot; J. F. Beche; S. Bonnet; P. Audebert; G. Regis; B. Zongo; S. Robinet; C. Condemine; C. Mestais; R. Guillemaud

2011-01-01

255

Automated diagnosis of epileptic EEG using entropies  

Microsoft Academic Search

Epilepsy is a neurological disorder characterized by the presence of recurring seizures. Like many other neurological disorders, epilepsy can be assessed by the electroencephalogram (EEG). The EEG signal is highly non-linear and non-stationary, and hence, it is difficult to characterize and interpret it. However, it is a well-established clinical technique with low associated costs. In this work, we propose a

U. Rajendra Acharya; Filippo Molinari; S. Vinitha Sree; Subhagata Chattopadhyay; Kwan-Hoong Ng; Jasjit S. Suri

256

Sleep EEG Provides Biomarkers in Depression  

Microsoft Academic Search

Patients with depression frequently report impaired sleep. Objective sleep is recorded by sleep electroencephalogram (EEG).\\u000a Characteristic sleep-EEG changes in affective disorders include disinhibition of rapid-eye-movement (REM) sleep (shortened\\u000a REM latency, prolonged first REM periods, elevated REM density, and a measure of the amount of REMs), impaired sleep continuity\\u000a and changes of nonREM sleep (decreases of slow wave sleep and stage

Mayumi Kimura; Axel Steiger

257

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.

Fingelkurts, Al. A; Fingelkurts, An. A

2010-01-01

258

EEG analysis with nonlinear excitable media.  

PubMed

The detection of patterns embedded within a complex, nonstationary, and noisy background activity is a crucial and important task in EEG analysis. The authors present a biologically inspired, analog approach to EEG analysis that is conceptually different from a variety of statistical approaches currently used. A nonlinear, excitable, spatially extended medium that is composed of diffusively coupled model neurons is considered. When EEG recordings are applied as local perturbations to such an excitable neural tissue, the induced transient changes in the dynamics of the perturbed system can be regarded as an instantaneous characterization of transient processes in the brain reflected by the EEG, e.g., in the form of a sequence of correlated dynamical events (patterns). Nonlinear excitable media can be implemented in form of an array of locally coupled integrated analog nonlinear electrical circuits called cellular neural networks, which represent a next evolutionary step in the parallel analog computer architecture. Using cellular neural networks, the authors show that the concept of signal-induced pattern generation allows an almost instantaneous and unsupervised detection of seizure onsets in EEG recordings. In addition, they show that a cellular neural network can be trained in a supervised way to approximate the degree of synchronization in EEG recordings. The resulting pattern-recognition device may be suitable for the prediction of epileptic seizures. PMID:16357636

Chernihovskyi, Anton; Mormann, Florian; Müller, Markus; Elger, Christian E; Baier, Gerold; Lehnertz, Klaus

2005-10-01

259

Differences in the perceived music pleasantness between monolateral cochlear implanted and normal hearing children assessed by EEG.  

PubMed

The perception of the music in cochlear implanted (CI) patients is an important aspect of their quality of life. In fact, the pleasantness of the music perception by such CI patients can be analyzed through a particular analysis of EEG rhythms. Studies on healthy subjects show that exists a particular frontal asymmetry of the EEG alpha rhythm which can be correlated with pleasantness of the perceived stimuli (approach-withdrawal theory). In particular, here we describe differences between EEG activities estimated in the alpha frequency band for a monolateral CI group of children and a normal hearing one during the fruition of a musical cartoon. The results of the present analysis showed that the alpha EEG asymmetry patterns related to the normal hearing group refers to a higher pleasantness perception when compared to the cerebral activity of the monolateral CI patients. In fact, the present results support the statement that a monolateral CI group could perceive the music in a less pleasant way when compared to normal hearing children. PMID:24110962

Vecchiato, G; Maglione, A G; Scorpecci, A; Malerba, P; Graziani, I; Cherubino, P; Astolfi, L; Marsella, P; Colosimo, A; Babiloni, Fabio

2013-01-01

260

EEG identification of subgroups of men at risk for alcoholism?  

PubMed

Biological sons of male alcoholics constitute one group at high risk (HR) for the development of alcoholism, and were the subjects of this study. A low dose of alcohol (0.5 g/kg) was administered to HR and control subjects. On the basis of changes in the electroencephalographic (EEG) mean alpha frequency that occurred following alcohol administration, two HR subgroups were identified. Measures obtained after alcohol administration, comprising self-ratings and an observer's assessment, distinguished the HR subgroups and control subjects; measures of visuomotor performance did not. The findings are discussed in relation to two current etiological theories bearing on the development of alcoholism: a biopsychological perspective and an initial tolerance for alcohol effects. PMID:3237902

Pollock, V E; Gabrielli, W F; Mednick, S A; Goodwin, D W

1988-10-01

261

Power spectral EEG analysis and EEG variability in obsessive-compulsive disorder  

Microsoft Academic Search

Summary Spectral EEG characteristics of thirteen patients with severe Obsessive-Compulsive Disorder (OCD) were investigated topographically. The finding of predominantly left posterior frontal to mid-temporal theta-2 is discussed in light of previous EEG studies and recent neuroradiologic findings.

Peter Perros; Edwin S. Young; James J. Ritson; Greg W. Price; Peter Mann

1992-01-01

262

Quality of EEG in simultaneous EEG-fMRI for epilepsy  

Microsoft Academic Search

It is now possible to record the EEG continuously during fMRI studies. This is a very promising methodology that combines knowledge about neuronal activity and its metabolic response. The EEG recorded inside the fMRI scanner is, however, heavily contaminated by artifacts caused by the high intensity magnetic field and rapidly changing field gradients. Methods have been reported in the literature

Christian-G Bénar; Yahya Aghakhani; Yunhua Wang; Aaron Izenberg; Abdullah Al-Asmi; François Dubeau; Jean Gotman

2003-01-01

263

Evaluation of an adaptive automation system using three EEG indices with a visual tracking task.  

PubMed

A system was evaluated for use in adaptive automation using two experiments with electroencephalogram (EEG) indices based on the beta, alpha, and theta bandwidths. Subjects performed a compensatory tracking task while their EEG was recorded and converted to one of three engagement indices: beta/(alpha + theta), beta/alpha, or 1/alpha. In experiment one, the tracking task was switched between manual and automatic modes depending on whether the subject's engagement index was increasing or decreasing under a positive or negative feedback condition. Subjects were run for three consecutive 16-min trials. In experiment two, the task was switched depending on whether the absolute level of the engagement index for the subject was above or below baseline levels. It was hypothesized that negative feedback would produce more switches between manual and automatic modes, and that the beta/(alpha + theta) index would be most effective. The results confirmed these hypotheses. Tracking performance was better under negative feedback in both experiments; also, the use of absolute levels of engagement in experiment two resulted in better performance. There were no systematic changes in these effects over three 16-min trials. The implications for the use of such systems for adaptive automation are discussed. PMID:10378439

Freeman, F G; Mikulka, P J; Prinzel, L J; Scerbo, M W

1999-05-01

264

EEG Sleep Spectra in Older Adults Across All Circadian Phases During NREM Sleep  

PubMed Central

Study Objectives: Healthy aging is associated with changes in sleep-wake regulation, and those changes often lead to problems sleeping, both during the night and during daytime. We aimed to examine the electroencephalographic (EEG) sleep spectra during non-rapid eye movement (NREM) sleep when sleep was scheduled at all times of day. Design/Interventions: After three 24-h baseline (BL) days, participants were scheduled to live on 20-hour “days” consisting of 6.7 hours of bed rest and 13.3 hours of wakefulness for 12 consecutive days (forced desynchrony, FD). The EEG was recorded from a central derivation during all scheduled sleep episodes, with subsequent visual scoring and spectral analysis. Setting: Intensive Physiological Monitoring Unit of the Brigham & Women's Hospital General Clinical Research Center. Participants: Twenty-four healthy older subjects (64.2 ± 6.3 yr; 13 women, 11 men) Measurements and Results: Compared with BL nights, EEG activity in the slow wave (0.5 to 5.25 Hz), theta (6 to 6.25 and 7 Hz), alpha (10 to 11.25 Hz), and high spindle range (14.5 to 15.5 Hz) was significantly greater during FD, when subjects slept across many times of day and night. During FD, there was a significant interaction between homeostatic and circadian factors, such that EEG delta activity (0.5 to 1.5 Hz) was higher in the biological morning/early afternoon than at other times. EEG activity was significantly increased in almost all frequency ranges (0.5 to 21 Hz) during the biological day, as compared with the biological night, except for the lower EEG spindle range (12.25 to 14 Hz). Overall, EEG beta activity was positively correlated with wakefulness and negatively correlated with total sleep time. Conclusion: Our findings provide some new evidence for the underlying mechanisms that contribute to age-related difficulties in sleep consolidation, especially when sleep occurs during the daytime. Citation: Münch M; Silva EJ; Ronda JM; Czeisler CA; Duffy JF. EEG sleep spectra in older adults across all circadian phases during NREM sleep. SLEEP 2010;33(3):389-401.

Munch, Mirjam; Silva, Edward J.; Ronda, Joseph M.; Czeisler, Charles A.; Duffy, Jeanne F.

2010-01-01

265

Adrenocorticotropin-related modulation of the human EEG and individual variability.  

PubMed

During a 6-h period in resting conditions, the blood concentrations at rest of cortisol, glucose and the adrenocorticotropic hormone (ACTH) varied spontaneously within physiological ranges in eight healthy male volunteers (24.5+/-1.7 years), without pulsatile changes, correlation among variables, or indications of stress response. The power of the 6.5-14.0 Hz physiological 'alpha' rhythm of the electroencephalogram (EEG) proved inverted-U correlated with the ACTH concentration (with maximum power at 12-14 pmol/l ACTH) but was independent from the extent of ACTH change or from cortisol/glucose concentrations. Two subgroups of subjects with low/high EEG power values could be separated depending on ACTH concentration, with estimated cut-off at 7-8 pmol/l. A direct ACTH modulation of brain electrophysiology or common factors (e.g. the corticotropin-releasing hormone) pacing both ACTH and EEG are suggested and may account for individual EEG differences. PMID:10218877

Sannita, W G; Loizzo, A; Garbarino, S; Gesino, D; Massimilla, S; Ogliastro, C

1999-03-12

266

Mal-Adaptation of Event-Related EEG Responses Preceding Performance Errors  

PubMed Central

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.

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

2010-01-01

267

Relationship between EEG power and rhythm synchronization in health and cognitive pathology.  

PubMed

We report here studies of comparative measures of spectral density and cortical interactions in EEG rhythms in health and schizophrenia. In healthy subjects, all rhythms were symmetrical and synchronous. In "acute" schizophrenia, unlike the situation in health, there was asymmetry (predominantly right-sided) in the distribution of the spectral power of EEG rhythms. In chronic patients, asymmetry was less marked, though the power of most EEG rhythms was significantly lower than in the other two study groups. "Acute" patients showed a lack of interhemisphere interactions for all rhythms apart from the alpha rhythm, while the number of cortical interactions in chronic patients was rather lower than that in the "acute" patients, though there were significantly fewer than in healthy subjects. In addition, the gamma range showed only one interhemisphere association in the posterior areas. These neurophysiological characteristics may underlie a number of the impairments of mental activity in patients with schizophrenia. These data may also indicate that the linkage between power characteristics and synchronization of EEG rhythms is a necessary condition for normal perceptive and cognitive activity and the organization of behavior. PMID:16783519

Strelets, V B; Garakh, Zh V; Novototskii-Vlasov, V Yu; Magomedov, R A

2006-07-01

268

Spatial and temporal EEG dynamics of dual-task driving performance  

PubMed Central

Background Driver distraction is a significant cause of traffic accidents. The aim of this study is to investigate Electroencephalography (EEG) dynamics in relation to distraction during driving. To study human cognition under a specific driving task, simulated real driving using virtual reality (VR)-based simulation and designed dual-task events are built, which include unexpected car deviations and mathematics questions. Methods We designed five cases with different stimulus onset asynchrony (SOA) to investigate the distraction effects between the deviations and equations. The EEG channel signals are first converted into separated brain sources by independent component analysis (ICA). Then, event-related spectral perturbation (ERSP) changes of the EEG power spectrum are used to evaluate brain dynamics in time-frequency domains. Results Power increases in the theta and beta bands are observed in relation with distraction effects in the frontal cortex. In the motor area, alpha and beta power suppressions are also observed. All of the above results are consistently observed across 15 subjects. Additionally, further analysis demonstrates that response time and multiple cortical EEG power both changed significantly with different SOA. Conclusions This study suggests that theta power increases in the frontal area is related to driver distraction and represents the strength of distraction in real-life situations.

2011-01-01

269

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

270

Ordinal patterns in epileptic brains: Analysis of intracranial EEG and simultaneous EEG-fMRI  

NASA Astrophysics Data System (ADS)

Epileptic seizures are associated with high behavioral stereotypy of the patients. In the EEG of epilepsy patients characteristic signal patterns can be found during and between seizures. Here we use ordinal patterns to analyze EEGs of epilepsy patients and quantify the degree of signal determinism. Besides relative signal redundancy and the fraction of forbidden patterns we introduce the fraction of under-represented patterns as a new measure. Using the logistic map, parameter scans are performed to explore the sensitivity of the measures to signal determinism. Thereafter, application is made to two types of EEGs recorded in two epilepsy patients. Intracranial EEG shows pronounced determinism peaks during seizures. Finally, we demonstrate that ordinal patterns may be useful for improving analysis of non-invasive simultaneous EEG-fMRI.

Rummel, C.; Abela, E.; Hauf, M.; Wiest, R.; Schindler, K.

2013-06-01

271

EEG features extraction for motor imagery.  

PubMed

Motor imagery is the mental simulation of a motor act that includes preparation for movement, passive observations of action and mental operations of motor representations implicitly or explicitly. Motor imagery as preparation for immediate movement likely involves the motor executive brain regions. Implicit mental operations of motor representations are considered to underlie cognitive functions. Another problem concerning neuro-imaging studies on motor imagery is that the performance of imagination is very difficult to control. The ability of an individual to control its EEG may enable him to communicate without being able to control their voluntary muscles. Communication based on EEG signals does not require neuromuscular control and the individuals who have neuromuscular disorders and who may have no more control over any of their conventional communication abilities may still be able to communicate through a direct brain-computer interface. A brain-computer interface replaces the use of nerves and muscles and the movements they produce with electrophysiological signals and is coupled with the hardware and software that translate those signals into physical actions. One of the most important components of a brain-computer interface is the EEG feature extraction procedure. This paper presents an approach that uses self-organizing fuzzy neural network based time series prediction that performs EEG feature extraction in the time domain only. EEG is recorded from two electrodes placed on the scalp over the motor cortex. EEG signals from each electrode are predicted by a single fuzzy neural network. Features derived from the mean squared error of the predictions and from the mean squared of the predicted signals are extracted from EEG data by means of a sliding window. The architecture of the two auto-organizing fuzzy neural networks is a network with multi inputs and single output. PMID:17945624

Cososchi, Stefan; Strungaru, Rodica; Ungureanu, Alexandru; Ungureanu, Mihaela

2006-01-01

272

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

273

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.

Cannon, Rex L.; Trudeau, David L.

2008-01-01

274

EEG patterns from acute to chronic stroke phases in focal cerebral ischemic rats: correlations with functional recovery.  

PubMed

Monitoring the neural activities from the ischemic penumbra provides critical information on neurological recovery after stroke. The purpose of this study is to evaluate the temporal alterations of neural activities using electroencephalography (EEG) from the acute phase to the chronic phase, and to compare EEG with the degree of post-stroke motor function recovery in a rat model of focal ischemic stroke. Male Sprague-Dawley rats were subjected to 90 min transient middle cerebral artery occlusion surgery followed by reperfusion for seven days (n = 58). The EEG signals were recorded at the pre-stroke phase (0 h), acute phase (3, 6 h), subacute phase (12, 24, 48, 72 h) and chronic phase (96, 120, 144, 168 h) (n = 8). This study analyzed post-stroke seizures and polymorphic delta activities (PDAs) and calculated quantitative EEG parameters such as the alpha-to-delta ratio (ADR). The ADR represented the ratio between alpha power and delta power, which indicated how fast the EEG activities were. Forelimb and hindlimb motor functions were measured by De Ryck's test and the beam walking test, respectively. In the acute phase, delta power increased fourfold with the occurrence of PDAs, and the histological staining showed that the infarct was limited to the striatum and secondary sensory cortex. In the subacute phase, the alpha power reduced to 50% of the baseline, and the infarct progressed to the forelimb cortical region. ADRs reduced from 0.23 ± 0.09 to 0.04 ± 0.01 at 3 h in the acute phase and gradually recovered to 0.22 ± 0.08 at 168 h in the chronic phase. In the comparison of correlations between the EEG parameters and the limb motor function from the acute phase to the chronic phase, ADRs were found to have the highest correlation coefficients with the beam walking test (r = 0.9524, p < 0.05) and De Ryck's test (r = 0.8077, p < 0.05). This study measured EEG activities after focal cerebral ischemia and showed that functional recovery was closely correlated with the neural activities in the penumbra. Longitudinal EEG monitoring at different phases after a stroke can provide information on the neural activities, which are well correlated with the motor function recovery. PMID:23524534

Zhang, Shao-jie; Ke, Zheng; Li, Le; Yip, Shea-ping; Tong, Kai-yu

2013-04-01

275

Synchronization of EEG: bivariate and multivariate measures.  

PubMed

Synchronization behavior of electroencephalographic (EEG) signals is important for decoding information processing in the human brain. Modern multichannel EEG allows a transition from traditional measurements of synchronization in pairs of EEG signals to whole-brain synchronization maps. The latter can be based on bivariate measures (BM) via averaging over pair-wise values or, alternatively, on multivariate measures (MM), which directly ascribe a single value to the synchronization in a group. In order to compare BM versus MM, we applied nine different estimators to simulated multivariate time series with known parameters and to real EEGs.We found widespread correlations between BM and MM, which were almost frequency-independent for all the measures except coherence. The analysis of the behavior of synchronization measures in simulated settings with variable coupling strength, connection probability, and parameter mismatch showed that some of them, including S-estimator, S-Renyi, omega, and coherence, aremore sensitive to linear interdependences,while others, like mutual information and phase locking value, are more responsive to nonlinear effects. Onemust consider these properties together with the fact thatMM are computationally less expensive and, therefore, more efficient for the large-scale data sets than BM while choosing a synchronization measure for EEG analysis. PMID:24216751

Jalili, Mahdi; Barzegaran, Elham; Knyazeva, Maria G

2014-03-01

276

Insights on the neural basis of motor plasticity induced by theta burst stimulation from TMS-EEG.  

PubMed

Transcranial magnetic stimulation (TMS) is a useful tool to induce and measure plasticity in the human brain. However, the cortical effects are generally indirectly evaluated with motor-evoked potentials (MEPs) reflective of modulation of cortico-spinal excitability. In this study, we aim to provide direct measures of cortical plasticity by combining TMS with electroencephalography (EEG). Continuous theta-burst stimulation (cTBS) was applied over the primary motor cortex (M1) of young healthy adults, and we measured modulation of (i) MEPs, (ii) TMS-induced EEG evoked potentials (TEPs), (iii) TMS-induced EEG synchronization and (iv) eyes-closed resting EEG. Our results show the expected cTBS-induced decrease in MEP size, which we found to be paralleled by a modulation of a combination of TEPs. Furthermore, we found that cTBS increased the power in the theta band of eyes-closed resting EEG, whereas it decreased single-pulse TMS-induced power in the theta and alpha bands. In addition, cTBS decreased the power in the beta band of eyes-closed resting EEG, whereas it increased single-pulse TMS-induced power in the beta band. We suggest that cTBS acts by modulating the phase alignment between already active oscillators; it synchronizes low-frequency (theta and/or alpha) oscillators and desynchronizes high-frequency (beta) oscillators. These results provide novel insight into the cortical effects of cTBS and could be useful for exploring cTBS-induced plasticity outside of the motor cortex. PMID:23190020

Vernet, Marine; Bashir, Shahid; Yoo, Woo-Kyoung; Perez, Jennifer M; Najib, Umer; Pascual-Leone, Alvaro

2013-02-01

277

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.

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

2014-01-01

278

Automatic classification algorithms of the EEG monitor Narcotrend for routinely recorded EEG data from general anaesthesia: a validation study.  

PubMed

Impacts of hypnotic drugs on brain function are reflected in the EEG. The EEG monitor Narcotrend performs an automatic classification of the EEG using a scale which was proposed by Kugler for visual evaluation of the EEG. In this article the results of a validation study of the automatic classification algorithms implemented in the EEG monitor Narcotrend are presented. Visual and automatic classification of EEG data recorded in routine clinical practice were compared. The correlation between visual and automatic assessment was high (Spearman rank correlation r = 0.90, prediction probability Pk = 0.90) and a sufficient agreement between visual and automatic assessment was achieved for 92% of the analysed EEG epochs. The results of the study suggest that the automatic classification algorithms implemented in the EEG monitor Narcotrend yield a reliable assessment of the depth of hypnosis. PMID:11921636

Schultz, B; Grouven, U; Schultz, A

2002-01-01

279

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.

280

Topographical EEG Mapping in a Case of Recurrent Sleep Terrors  

Microsoft Academic Search

Sleep terrors are characterized by marked CNS arousal and typically occur during stage 3-4 sleep within the first NREM cycle. Studies of the EEG during sleep terrors suggest that delta power and synchrony in the EEG may be important physiological markers of sleep terror presence and intensity. An EEG mapping study was undertaken with a single participant who experienced three

Antonio L. Zadra; Tore A. Nielsen

1998-01-01

281

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

282

[Autoregressive model order property for sleep EEG].  

PubMed

Traditional sleep scoring system describes the sleep EEG characterized by features in time domain as well as frequency domain. Power Spectral Density (PSD) is one of the well-used methods to observe the occurrence of specified rhythms. However, the parameter model based PSD estimation is used with the assumption that the model order is determined as low as possible through prior knowledge. This paper briefs the development of Autoregressive Model Order (ARMO) criterion, and provides the distribution of ARMOs for specified sleep EEG, which shows that ARMOs concentrate on several well separated regions that are indicative of the microstructure and transition states. This study suggests the promising perspective of ARMO as a special EEG feature for weighing complexity, randomness and rhythm components. PMID:15250141

Wang, Tao; Wang, Guohui; Feng, Huanqing

2004-06-01

283

A wireless multichannel EEG recording platform.  

PubMed

A wireless multichannel data acquisition system is being designed for ElectroEncephaloGraphy (EEG) recording. The system is based on a custom integrated circuit (ASIC) for signal conditioning, amplification and digitization and also on commercial components for RF transmission. It supports the RF transmission of a 32-channel EEG recording sampled at 1 kHz with a 12-bit resolution. The RF communication uses the MICS band (Medical Implant Communication Service) at 402-405 Mhz. This integration is a first step towards a lightweight EEG cap for Brain Computer Interface (BCI) studies. Here, we present the platform architecture and its submodules. In vivo validations are presented with noise characterization and wireless data transfer measurements. PMID:22255783

Filipe, S; Charvet, G; Foerster, M; Porcherot, J; Bêche, J F; Bonnet, S; Audebert, P; Régis, G; Zongo, B; Robinet, S; Condemine, C; Mestais, C; Guillemaud, R

2011-01-01

284

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

PubMed

A design for a modular, compact, and accurate wireless electroencephalograph (EEG) system is proposed. EEG is the only non-invasive measure for neuronal function of the brain. Using a number of digital signal processing (DSP) techniques, this neuronal function can be acquired and processed into meaningful representations of brain activity. The system described here utilizes Bluetooth to wirelessly transmit the digitized brain signal for an end application use. In this way, the system is portable, and modular in terms of the device to which it can interface. Brain Computer Interface (BCI) has become a popular extension of EEG systems in modern research. This design serves as a platform for applications using BCI capability. PMID:24111196

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

2013-01-01

285

Multivariate temporal dictionary learning for EEG.  

PubMed

This article addresses the issue of representing electroencephalographic (EEG) signals in an efficient way. While classical approaches use a fixed Gabor dictionary to analyze EEG signals, this article proposes a data-driven method to obtain an adapted dictionary. To reach an efficient dictionary learning, appropriate spatial and temporal modeling is required. Inter-channels links are taken into account in the spatial multivariate model, and shift-invariance is used for the temporal model. Multivariate learned kernels are informative (a few atoms code plentiful energy) and interpretable (the atoms can have a physiological meaning). Using real EEG data, the proposed method is shown to outperform the classical multichannel matching pursuit used with a Gabor dictionary, as measured by the representative power of the learned dictionary and its spatial flexibility. Moreover, dictionary learning can capture interpretable patterns: this ability is illustrated on real data, learning a P300 evoked potential. PMID:23428648

Barthélemy, Q; Gouy-Pailler, C; Isaac, Y; Souloumiac, A; Larue, A; Mars, J I

2013-04-30

286

EEG should be performed during induced hypothermia.  

PubMed

Induced hypothermia has improved neurological outcome after cardiac arrest. Even though anoxic insults to the brain often provoke epileptic activity, it is unclear whether EEG monitoring is necessary in these patients. We report the case of a 53-year-old female who suffered cardiac arrest. During induced hypothermia extensive shivering was managed by sedation and curare. After their discontinuation convulsions appeared and status epilepticus was disclosed on EEG recording, and was treated by thiopental infusion for 10 days. The patient recovered slowly and has now regained independent living (CPC 1). In induced hypothermia several factors including the use of curare, may conceal clinical signs of epileptic activity. We therefore suggest a broader use of EEG in these patients. PMID:16325321

Hovland, Anders; Nielsen, Erik Waage; Klüver, Jens; Salvesen, Rolf

2006-01-01

287

Magnesium valproate in learning disabled children with interictal paroxysmal EEG patterns: Preliminary report.  

PubMed

Previous studies have investigated whether routine use of antiepileptic drugs is adequate to improve cognitive abilities in children who are learning disabled not otherwise specified (LD NOS) and who display interictal paroxysmal patterns in the electroencephalogram (EEG) but do not have epilepsy, and the findings of these studies have been controversial. In the current study, 112 LD children without epilepsy were assessed; however, only 18 met the strict inclusion/exclusion criteria in order to obtain a homogeneous sample. These children showed interictal paroxysmal patterns in the EEG, and a randomized, double-blind trial was carried out on them. The children were treated with either magnesium valproate (MgV; 20mg/kg/day) or a placebo for six months, and differences in WISC subtests, in a computerized reading skills battery (BTL) and EEG recordings were evaluated between groups before and after the treatment period. Performance IQ score and several items of the BTL (rhymes and ordering of words) improved in children who received MgV, whereas no changes were observed in the placebo group. No changes in the number of interictal paroxysmal patterns were observed in any group; however increased EEG currents at 10.92 and 12.87Hz (alpha band) in posterior regions and decreased currents in frequencies within the theta band (3.90, 4.29 and 5.07Hz) in frontal regions and at 4.68 and 5.46Hz in the parietal cortex were observed, suggesting an improvement in EEG maturation. PMID:21291957

Porras-Kattz, Eneida; Harmony, Thalía; Ricardo-Garcell, Josefina; Galán, Lídice; Fernández, Thalía; Prado-Alcalá, Roberto; Avecilla-Ramírez, Gloria; Sánchez-Moreno, Liliana; Barrera-Reséndiz, Jesús; Corsi-Cabrera, María; Valencia-Solís, Elizabeth

2011-04-01

288

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)

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

1994-01-01

289

CRS-R score in disorders of consciousness is strongly related to spectral EEG at rest.  

PubMed

Patients suffering from disorders of consciousness still present a diagnostic challenge due to the fact that their assessment is mainly based on behavioral scales with their motor responses often being strongly impaired. We therefore focused on resting electroencephalography (EEG) in order to reveal potential alternative measures of the patient's current state independent of rather complex abilities (e.g., language comprehension). Resting EEG was recorded in nine minimally conscious state (MCS) and eight vegetative state/unresponsive wakefulness syndrome (VS/UWS) patients. Behavioral assessments were conducted using the Coma-Recovery Scale-Revised (CRS-R). The signal was analyzed in the frequency domain and association between resting EEG and CRS-R score as well as clinical diagnosis were calculated using Pearson correlation and repeated-measures ANOVAs. The analyses revealed robust positive correlations between CRS-R score and ratios between frequencies above 8 Hz and frequencies below 8 Hz. Furthermore, the frequency of the spectral peak was also highly indicative of the patient's CRS-R score. Concerning differences between clinical diagnosis and healthy controls, it could be revealed that while VS/UWS patients showed higher delta and theta activity than controls, MCS did not differ from controls in this frequency range. Alpha activity, on the other hand, was strongly decreased in both patient groups as compared to controls. The strong relationship between various resting EEG parameters and CRS-R score provides significant clinical relevance. Not only is resting activity easily acquired at bedside, but furthermore, it does not depend on explicit cooperation of the patient. Especially in cases where behavioral assessment is difficult or ambiguous, spectral analysis of resting EEG can therefore complement clinical diagnosis. PMID:23765089

Lechinger, Julia; Bothe, Kathrin; Pichler, Gerald; Michitsch, Gabriele; Donis, Johann; Klimesch, Wolfgang; Schabus, Manuel

2013-09-01

290

Interictal functional connectivity of human epileptic networks assessed by intracerebral EEG and BOLD signal fluctuations.  

PubMed

In this study, we aimed to demonstrate whether spontaneous fluctuations in the blood oxygen level dependent (BOLD) signal derived from resting state functional magnetic resonance imaging (fMRI) reflect spontaneous neuronal activity in pathological brain regions as well as in regions spared by epileptiform discharges. This is a crucial issue as coherent fluctuations of fMRI signals between remote brain areas are now widely used to define functional connectivity in physiology and in pathophysiology. We quantified functional connectivity using non-linear measures of cross-correlation between signals obtained from intracerebral EEG (iEEG) and resting-state functional MRI (fMRI) in 5 patients suffering from intractable temporal lobe epilepsy (TLE). Functional connectivity was quantified with both modalities in areas exhibiting different electrophysiological states (epileptic and non affected regions) during the interictal period. Functional connectivity as measured from the iEEG signal was higher in regions affected by electrical epileptiform abnormalities relative to non-affected areas, whereas an opposite pattern was found for functional connectivity measured from the BOLD signal. Significant negative correlations were found between the functional connectivities of iEEG and BOLD signal when considering all pairs of signals (theta, alpha, beta and broadband) and when considering pairs of signals in regions spared by epileptiform discharges (in broadband signal). This suggests differential effects of epileptic phenomena on electrophysiological and hemodynamic signals and/or an alteration of the neurovascular coupling secondary to pathological plasticity in TLE even in regions spared by epileptiform discharges. In addition, indices of directionality calculated from both modalities were consistent showing that the epileptogenic regions exert a significant influence onto the non epileptic areas during the interictal period. This study shows that functional connectivity measured by iEEG and BOLD signals give complementary but sometimes inconsistent information in TLE. PMID:21625517

Bettus, Gaelle; Ranjeva, Jean-Philippe; Wendling, Fabrice; Bénar, Christian G; Confort-Gouny, Sylviane; Régis, Jean; Chauvel, Patrick; Cozzone, Patrick J; Lemieux, Louis; Bartolomei, Fabrice; Guye, Maxime

2011-01-01

291

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

292

Autism and EEG phase reset: deficient GABA mediated inhibition in thalamo-cortical circuits.  

PubMed

The purpose of this study was to explore the relationship between electroencephalogram (EEG) phase reset in autism spectrum disorder (ASD) subjects as compared to age matched control subjects. The EEG was recorded from 19 scalp locations from 54 autistic subjects and 241 control subjects ranging in age from 2.6 years to 11 years. Complex demodulation was used to compute instantaneous phase differences between all pairs of electrodes and the 1st and 2nd derivatives were used to measure phase reset by phase shift duration and phase lock duration. In both short (6 cm) and long (21-24 cm) inter-electrode distances phase shift duration in ASD subjects was significantly shorter in all frequency bands but especially in the alpha-1 frequency band (8-10 Hz) (p < .0001). Phase lock duration was significantly longer in the alpha-2 frequency band (10-12 Hz) in ASD subjects (p < .0001). An anatomical gradient was present with the occipital-parietal regions the most significant. The findings in this study support the hypothesis that neural resource recruitment occurs in the lower frequency bands and especially the alpha-1 frequency band while neural resource allocation occurs in the alpha-2 frequency band. The results are consistent with a general GABA inhibitory neurotransmitter deficiency resulting in reduced number and/or strength of thalamo-cortical connections in autistic subjects. PMID:20183733

Thatcher, Robert W; North, Duane M; Neubrander, James; Biver, Carl J; Cutler, Stewart; Defina, Phillip

2009-01-01

293

Routine electroencephalographic (EEG) monitoring during carotid endarterectomy.  

PubMed Central

Controversy continues concerning the advisability of routine shunting, no shunting, or selective shunting during carotid endarterectomy. Because of its reflection of the physiologic state of the end organ, the authors chose routine 18 lead EEG monitoring as a guide to selective shunting and as an indication of adequate shunt function during all carotid endarterectomies performed from December 1977 through July 1982. In that period, 200 patients underwent 219 endarterectomies under general anesthesia and EEG monitoring. Ischemic EEG changes at the time of carotid cross clamping suggested the need for intraluminal shunts in 16% of patients. Insertion of shunts restored the EEG pattern to normal in all instances, although in two patients, adjustment of the shunt was required to maintain this results. EEG changes requiring shunting occurred in 10% of patients with unilateral disease, in 27% of patients with bilateral disease, and in 42% of patients with unilateral stenosis and contralateral occlusion. Twenty-seven patients had small fixed neurologic deficits before operation. Surgery was not delayed in these individuals who demonstrated no increased requirement for shunts and no new postoperative neurologic deficits. In the group of 150 endarterectomies performed as separate procedures, there was one (0.7%) fixed neurologic deficit after operation, one transient deficit (0.7%), and one death (0.7%). Sixty-nine endarterectomies were performed simultaneously with open heart surgery and were associated with one fixed neurologic deficit (1.4%) and two transient deficits (2.9%). All four deaths in this group were attributable to the cardiac surgical procedures. These results indicate that selective shunting based on EEG monitoring permits the safe performance of carotid endarterectomy, even in patients considered to be at high risk for postoperative neurologic deficit.

Whittemore, A D; Kauffman, J L; Kohler, T R; Mannick, J A

1983-01-01

294

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

295

Manual Lymph Drainage Attenuates Frontal EEG Asymmetry in Subjects with Psychological Stress: A Preliminary Study  

PubMed Central

[Purpose] The purpose of this preliminary study was to investigate the effect of manual lymph drainage (MLD) of the neck on frontal electroencephalogram (EEG) asymmetry in subjects with psychological stress. [Subjects] Thirteen subjects with psychological stress participated in the study. [Methods] Subjects received MLD of the neck for 15?min. [Results] Analysis of the frontal asymmetry index showed that the energy shift in the alpha frequency band from the left hemisphere to the right hemisphere after MLD resulted in greater left-side activation (positive asymmetry values), which could be related to the positive emotional state observed particularly in the F7–F8 area. [Conclusion] These preliminary findings suggest that frontal EEG asymmetry was significantly attenuated after MLD.

Shim, Jung-Myo; Kim, Sung-Joong

2014-01-01

296

Fractal Dimension in Epileptic EEG Signal Analysis  

NASA Astrophysics Data System (ADS)

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

Uthayakumar, R.

297

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

298

Sex differences between the combined and inattentive types of attention-deficit/hyperactivity disorder: an EEG perspective.  

PubMed

This study investigated sex differences between the EEGs of Combined and Inattentive types of attention-deficit/hyperactivity disorder (AD/HD) within boys and girls aged 8-12 years. Subject groups included 80 AD/HD Combined type (40 boys and 40 girls), 80 AD/HD Inattentive type (40 boys and 40 girls) and 80 controls (40 boys and 40 girls). An eyes-closed resting EEG was recorded and Fourier transformed to provide estimates for absolute and relative power in the delta, theta, alpha and beta frequency bands, as well as total power and the theta/beta ratio. The boy AD/HD groups, compared with boy controls, had greater absolute and relative theta, greater theta/beta ratio, reduced absolute and relative alpha, and reduced absolute and relative beta. The girl AD/HD groups, compared with girl controls, had greater absolute delta, greater absolute and relative theta, greater theta/beta ratio, greater total power, and reduced relative delta and relative beta. Between AD/HD types, Combined type boys had globally greater absolute and relative theta, greater theta/beta ratio, and less relative alpha than Inattentive type boys. While topographical differences emerged, there were no significant global differences between AD/HD types in girls. That is, EEG differences between AD/HD types are dissimilar in boys and girls. Different EEG maturational patterns between boys and girls also obscure AD/HD-related EEG abnormalities. These results have important implications for our understanding of AD/HD in girls. Ignoring such sex differences may have compromised the value of previous AD/HD investigations, and these sex differences should be recognised in future research. PMID:23603052

Dupuy, Franca E; Barry, Robert J; Clarke, Adam R; McCarthy, Rory; Selikowitz, Mark

2013-09-01

299

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.

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

2014-01-01

300

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.

Barwick, Fiona; Arnett, Peter; Slobounov, Semyon

2011-01-01

301

Artificial neural network based approach to EEG signal simulation.  

PubMed

In this paper a new approach to the electroencephalogram (EEG) signal simulation based on the artificial neural networks (ANN) is proposed. The aim was to simulate the spontaneous human EEG background activity based solely on the experimentally acquired EEG data. Therefore, an EEG measurement campaign was conducted on a healthy awake adult in order to obtain an adequate ANN training data set. As demonstration of the performance of the ANN based approach, comparisons were made against autoregressive moving average (ARMA) filtering based method. Comprehensive quantitative and qualitative statistical analysis showed clearly that the EEG process obtained by the proposed method was in satisfactory agreement with the one obtained by measurements. PMID:23627624

Tomasevic, Nikola M; Neskovic, Aleksandar M; Neskovic, Natasa J

2012-06-01

302

Alpha brainwave training and perception of time passing: Preliminary findings  

Microsoft Academic Search

The ability to generate alpha brainwaves has been associated with the self-regulation of stress. It has been suggested that generation of these brainwaves, above what is to be expected in a normal 24-hour EEG, contributes to an expanded state of consciousness. This study attempted to test Newman's theory that expansion of consciousness could be observed in perception of time passing.

Margaret S. Wacker

1996-01-01

303

Visualizing and Rhyming Cause Differences in Alpha Suppression.  

National Technical Information Service (NTIS)

Alpha rhythms of the EEG are strongest at the occipital regions of the head, and the visual cortex is apparently a major contributor. It has been suggested that visual cortex is involved in forming and processing mental images. The purpose of this experim...

L. Kaufman

1989-01-01

304

Genetics of alcoholism using intermediate phenotypes.  

PubMed

This article represents the proceedings of a symposium at the 2002 meeting of the Research Society on Alcoholism in San Francisco, CA. It was organized by Mary-Anne Enoch and David Goldman and chaired by David Goldman. The presentations were (1) Two functional polymorphisms and their intermediate phenotypes in complex behaviors: COMT/executive cognition and anxiety and HTT/anxiety, by David Goldman; (2) Role of the EEG in determining genetic risk for alcoholism and anxiety disorders, by Mary-Anne Enoch; (3) The response to alcohol as an intermediate phenotype for alcoholism, by Marc A. Schuckit; and (4) Pharmacogenomic approaches to alcoholism treatment: toward a hypothesis, by Bankole A. Johnson. PMID:12605066

Enoch, Mary-Anne; Schuckit, Marc A; Johnson, Bankole A; Goldman, David

2003-02-01

305

A Physiology-Based Seizure Detection System for Multichannel EEG  

PubMed Central

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

Shen, Chia-Ping; Liu, Shih-Ting; Zhou, Wei-Zhi; Lin, Feng-Seng; Lam, Andy Yan-Yu; Sung, Hsiao-Ya; Chen, Wei; Lin, Jeng-Wei; Chiu, Ming-Jang; Pan, Ming-Kai; Kao, Jui-Hung; Wu, Jin-Ming; Lai, Feipei

2013-01-01

306

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.

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

2013-01-01

307

Nonlinear analysis of EEG for epileptic seizures.  

National Technical Information Service (NTIS)

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 EE...

L. M. Hively N. E. Clapp C. S. Daw W. F. Lawkins M. L. Eisenstadt

1995-01-01

308

EEG dipole modeling in complex partial epilepsy  

Microsoft Academic Search

Summary Visual inspection and qualitative impressions of clinical EEG abnormalities are being replaced by quantitative characterization of scalp voltage fields and dipole modeling of underlying cerebral sources. Three approaches have been used in the analysis of focal spikes of complex partial epilepsy. 1) Instantaneous, single dipole, inverse solutions for the voltage topography of the spike peak have revealed two distinct

John S. Ebersole

1991-01-01

309

Inferring Seizure Frequency From Brief EEG Recordings  

PubMed Central

Routine EEGs remain a cornerstone test in caring for people with epilepsy. Although rare, a self-limited seizure (clinical or electrographic only) may be observed during such brief EEGs. The implications of observing a seizure in this situation, especially with respect to inferring the underlying seizure frequency, are unclear. The issue is complicated by the inaccuracy of patient-reported estimations of seizure frequency. The treating clinician is often left to wonder whether the single seizure indicates very frequent seizures, or if it is of lesser significance. We applied standard concepts of probabilistic inference to a simple model of seizure incidence to provide some guidance for clinicians facing this situation. Our analysis establishes upper and lower bounds on the seizure rate implied by observing a single seizure during routine EEG. Not surprisingly, with additional information regarding the expected seizure rate, these bounds can be further constrained. This framework should aid the clinician in applying a more principled approach toward decision making in the setting of a single seizure on a routine EEG.

Westover, M. Brandon; Bianchi, Matt T.; Shafi, Mouhsin; Hoch, Daniel B.; Cole, Andrew J.; Chiappa, Keith; Cash, Sydney S.

2012-01-01

310

Inferring seizure frequency from brief EEG recordings.  

PubMed

Routine EEGs remain a cornerstone test in caring for people with epilepsy. Although rare, a self-limited seizure (clinical or electrographic only) may be observed during such brief EEGs. The implications of observing a seizure in this situation, especially with respect to inferring the underlying seizure frequency, are unclear. The issue is complicated by the inaccuracy of patient-reported estimations of seizure frequency. The treating clinician is often left to wonder whether the single seizure indicates very frequent seizures, or if it is of lesser significance. We applied standard concepts of probabilistic inference to a simple model of seizure incidence to provide some guidance for clinicians facing this situation. Our analysis establishes upper and lower bounds on the seizure rate implied by observing a single seizure during routine EEG. Not surprisingly, with additional information regarding the expected seizure rate, these bounds can be further constrained. This framework should aid the clinician in applying a more principled approach toward decision making in the setting of a single seizure on a routine EEG. PMID:23545768

Westover, M Brandon; Bianchi, Matt T; Shafi, Mouhsin; Hoch, Daniel B; Cole, Andrew J; Chiappa, Keith; Cash, Sydney S

2013-04-01

311

Recipes for the linear analysis of EEG  

Microsoft Academic Search

In this paper, we describe a simple set of “recipes” for the analysis of high spatial density EEG. We focus on a linear integration of multiple channels for extracting individual components without making any spatial or anatomical modeling assumptions, instead requiring particular statistical properties such as maximum difference, maximum power, or statistical independence. We demonstrate how corresponding algorithms, for example,

Lucas C. Parra; Clay D. Spence; Adam D. Gerson; Paul Sajda

2005-01-01

312

Extraction of "deep" components from scalp EEG.  

PubMed

In an attempt to delineate the relative contribution of surface versus deep components in the EEG of patients with 3 per second generalized spike-wave discharges and clinical petit mal seizures, a mathematical method was devised which allows the splitting of the EEG into two major subsystems. It is based on the observation that broad electrical fields tend to represent activity at deeper structures while discrete narrow fields centered at one electrode position tend to be of more superficial origin. Since source derivation intentionally suppresses broad potential fields, a differentiation between superficial and deep activity can be achieved by subtracting the source density values from the corresponding electrode potential values. This will provide those aspects of the EEG which are contributed mainly by deep generators. The resultant data can then be subjected to eigenfunction analysis which yields few uncorrelated components. The percentage of contribution of each electrode to the total component thus derived can then be displayed as a topographic map. When this methodology was applied to ictal EEGs of three patients consistent results were obtained. The "deep" data yielded mainly two components with mutually perpendicular directions. PMID:3152766

Hjorth, B; Rodin, E

1988-01-01

313

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

314

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

315

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

316

Functional connectivity of frontal cortex in healthy and ADHD children reflected in EEG coherence.  

PubMed Central

Abnormal functional brain connectivity is a candidate factor in developmental brain disorders associated with cognitive dysfunction. We analyzed a substantial (ten minute per subject) record of dense array EEG with spectral power and coherence methods in ADHD (n = 42) and Control (n = 21) 10–13 year old children. We found topographically distinct narrow band coherence differences between subject groups: ADHD subjects showed elevated coherence in the lower alpha (8 Hz) band and reduced coherence in the upper alpha (10–11 Hz) band. The 8 Hz ADHD elevation, and a 2–6 Hz Control group coherence elevation, were independent of stimulus presentation. In response to visual stimulation, the ADHD group exhibited reduced evoked potential power and elevated frontal coherence. Only the upper alpha band control group coherence elevation discriminated according to ADHD group medication status. The findings suggest a static state of deficient connectivity in ADHD, and a stimulus induced state of over-connectivity within and between frontal hemispheres.

Murias, Michael; Swanson, James M.; Srinivasan, Ramesh

2007-01-01

317

EEG microstates of wakefulness and NREM sleep.  

PubMed

EEG-microstates exploit spatio-temporal EEG features to characterize the spontaneous EEG as a sequence of a finite number of quasi-stable scalp potential field maps. So far, EEG-microstates have been studied mainly in wakeful rest and are thought to correspond to functionally relevant brain-states. Four typical microstate maps have been identified and labeled arbitrarily with the letters A, B, C and D. We addressed the question whether EEG-microstate features are altered in different stages of NREM sleep compared to wakefulness. 32-channel EEG of 32 subjects in relaxed wakefulness and NREM sleep was analyzed using a clustering algorithm, identifying the most dominant amplitude topography maps typical of each vigilance state. Fitting back these maps into the sleep-scored EEG resulted in a temporal sequence of maps for each sleep stage. All 32 subjects reached sleep stage N2, 19 also N3, for at least 1 min and 45 s. As in wakeful rest we found four microstate maps to be optimal in all NREM sleep stages. The wake maps were highly similar to those described in the literature for wakefulness. The sleep stage specific map topographies of N1 and N3 sleep showed a variable but overall relatively high degree of spatial correlation to the wake maps (Mean: N1 92%; N3 87%). The N2 maps were the least similar to wake (mean: 83%). Mean duration, total time covered, global explained variance and transition probabilities per subject, map and sleep stage were very similar in wake and N1. In wake, N1 and N3, microstate map C was most dominant w.r.t. global explained variance and temporal presence (ratio total time), whereas in N2 microstate map B was most prominent. In N3, the mean duration of all microstate maps increased significantly, expressed also as an increase in transition probabilities of all maps to themselves in N3. This duration increase was partly--but not entirely--explained by the occurrence of slow waves in the EEG. The persistence of exactly four main microstate classes in all NREM sleep stages might speak in favor of an in principle maintained large scale spatial brain organization from wakeful rest to NREM sleep. In N1 and N3 sleep, despite spectral EEG differences, the microstate maps and characteristics were surprisingly close to wakefulness. This supports the notion that EEG microstates might reflect a large scale resting state network architecture similar to preserved fMRI resting state connectivity. We speculate that the incisive functional alterations which can be observed during the transition to deep sleep might be driven by changes in the level and timing of activity within this architecture. PMID:22658975

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

2012-09-01

318

Atypical alpha asymmetry in adults with ADHD*  

PubMed Central

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 asymmetry has been associated with ADHD-like traits such as reduced reward responsiveness, a lack of inhibition toward aversive experience, and increased approach behaviors, and previous work has indicated increased rightward alpha asymmetry in children with ADHD. The current study explores whether increased rightward alpha asymmetry is also evident in adults with ADHD. Method We assessed low (8– 10 Hz) and high (10– 12 Hz) alpha asymmetry in adults with ADHD (n = 29) versus controls (n = 62) during baseline and cognitive activation conditions for nine homologous electrode pairs along the anterior–posterior axis. Result Seven results emerged (p < .05) showing increased rightward alpha asymmetry in adults with ADHD. This occurred in three specific electrode pairs across two testing conditions, and five of six results occurred in the lower alpha band. Finally, post hoc analysis indicated that increased rightward alpha asymmetry was generally associated with greater numbers of ADHD symptoms—with a possible parietal association for inattentive and a fronto-temporal association for hyperactivity symptoms. Conclusions Increased rightward alpha asymmetry previously observed in children with ADHD appears to be a developmentally persistent feature of ADHD.

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

2009-01-01

319

Roles of Adrenergic ?1 and Dopamine D1 and D2 Receptors in the Mediation of the Desynchronization Effects of Modafinil in a Mouse EEG Synchronization Model  

PubMed Central

Background Synchronized electroencephalogram (EEG) activity is observed in pathological stages of cognitive impairment and epilepsy. Modafinil, known to increase the release of catecholamines, is a potent wake-promoting agent, and has shown some abilities to desynchronize EEG,but its receptor mechanisms by which modafinil induces desynchoronization remain to be elucidated. Here we used a pharmacological EEG synchronization model to investigate the involvement of adrenergic ?1 receptors (R, ?1R) and dopamine (DA) D1 and D2 receptors (D1Rs and D2Rs) on modafinil-induced desynchronization in mice. Methodology/Principal Findings Mice were treated with cholinergic receptor antagonist scopolamine and monoamine depletor reserpine to produce experimental EEG synchronization characterized by continuous large-amplitude synchronized activity, with prominent increased delta and decreased theta, alpha, and beta power density. The results showed that modafinil produced an EEG desynchronization in the model. This was characterized by a general decrease in amplitude of all the frequency bands between 0 and 20 Hz, a prominent reduction in delta power density, and an increase in theta power density. Adrenergic ?1R antagonist terazosin (1 mg/kg, i.p.) completely antagonized the EEG desynchronization effects of modafinil at 90 mg/kg. However, DA D1R and D2R blockers partially attenuated the effects of modafinil. The modafinil-induced decrease in the amplitudes of the delta, theta, alpha, and beta waves and in delta power density were completely abolished by pretreatment with a combination of the D1R antagonist SCH 23390 (30 µg/kg) and the D2R antagonist raclopride (2 mg/kg, i.p.). Conclusions/Significance These results suggest that modafinil-mediated desynchronization may be attributed to the activation of adrenergic ?1R, and dopaminergic D1R and D2R in a model of EEG synchronization.

Chen, Chang-Rui; Yang, Su-Rong; Liu, Yuan-Yuan; Qu, Wei-Min; Urade, Yoshihiro; Huang, Zhi-Li

2013-01-01

320

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.

Spence, Sarah J; Schneider, Mark T

2009-01-01

321

Modulation of EEG functional connectivity networks in subjects undergoing repetitive transcranial magnetic stimulation.  

PubMed

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

2014-01-01

322

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.

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

2014-01-01

323

[The EEG rhythms and psychological indices of emotions in reactive depression].  

PubMed

Power and topographic distribution of the EEG rhythms (delta, theta 1, theta 2, alpha, beta 1, and beta 2) were compared with the reactive and personal anxiety levels (by Spilberger) and parameters of subjective emotional semantic space (obtained by the method of subjective scaling). A general decrease in the EEG power was observed in reactive depression, with the exception of the theta-rhythm, the power of which was higher than that in healthy persons. The increase in the theta 2 power in depression was correlated with activation of the right frontal area ("the zone of negative emotions"), and its decrease was associated with activation of the left frontal area ("responsible" for positive emotions), enhancement of positive emotions in semantic emotional space, and with a decrease in personal anxiety. High alpha activity in healthy persons was negatively correlated with the activation of the "zone of negative emotions" while a decrease in the alpha-rhythm power was associated with anxiety enhancement and decrease in contribution of positive emotions in the semantic space. PMID:9182411

Strelets, V B; Danilova, N N; Kornilova, I V

1997-01-01

324

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.

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

2014-01-01

325

[Testing method of human body's current threshold for perception based on EEG analysis].  

PubMed

Electric and electronic products are required to pass through the certification on electrical safety performance before entering into the market in order to reduce electrical shock and electrical fire so as to protect the safety of people and property. The leakage current is the most important factor in testing the electrical safety performance and the test theory is based on the perception current effect and threshold. The traditional method testing the current threshold for perception only depends on the sensing of the human body and is affected by psychological factors. Some authors filter the effect of subjective sensation by using physiological and psychological statistical algorithm in recent years and the reliability and consistency of the experiment data are improved. We established an experiment system of testing the human hody's current threshold for perception based on EEG feature analysis, and obtained 967 groups of data. We used wavelet packet analysis to detect a wave from EEG, and used FFT to do spectral analysis on alpha wave before and after the current flew through the human body. The study has shown that about 97.72% alpha wave energy changes significantly when electrical stimulation occurs. It is well proved that when the EEG feature identification is applied to test the human body current threshold for perception, and meanwhile alpha wave energy change and human body sensing are used together to confirm if the current flowing through the human body reaches the perception threshold, the measurement of the human body current threshold for perception could be carried out objectively and accurately. PMID:24804476

Wang, Xiaofei; Shi, Lijuan; Li, Dong; Zhao, Xu; Shao, Haiming

2014-02-01

326

Screening EEG in Aircrew Selection: Clinical Aerospace Neurology Perspective  

NASA Technical Reports Server (NTRS)

As clinical aerospace neurologists we do not favor using screening EEG in pilot selection on unselected and otherwise asymptomatic individuals. The role of EEG in aviation screening should be as an adjunct to diagnosis, and the decision to disqualify a pilot should never be based solely on the EEG. Although a policy of using a screening EEG in an unselected population might detect an individual with a potentially increased relative risk, it would needlessly exclude many applicants who would probably never have a seizure. A diagnostic test performed on an asymptomatic individual without clinical indications, in a population with a low prevalence of disease (seizure) may be of limited or possibly detrimental value. We feel that rather than do EEGs on all candidates, a better approach would be to perform an EEG for a specific indication, such as family history of seizure, single convulsion (seizure) , history of unexplained loss of consciousness or head injury. Routine screening EEGs in unselected aviation applications are not done without clinical indication in the U.S. Air Force, Navy, or NASA. The USAF discontinued routine screening EEGs for selection in 1978, the U.S. Navy discontinued it in 1981 , and NASA discontinued it in 1995. EEG as an aeromedical screening tool in the US Navy dates back to 1939. The US Navy routinely used EEGs to screen all aeromedical personnel from 1961 to 1981. The incidence of epileptiform activity on EEG in asymptomatic flight candidates ranges from 0.11 to 2.5%. In 3 studies of asymptomatic flight candidates with epileptiform activity on EEG followed for 2 to 15 years, 1 of 31 (3.2%), 1 of 30 (3.3%), and 0 of 14 (0%) developed a seizure, for a cumulative risk of an individual with an epileptiform EEG developing a seizure of 2.67% (2 in 75). Of 28,658 student naval aviation personnel screened 31 had spikes and/or slow waves on EEG, and only 1 later developed a seizure. Of the 28,627 who had a normal EEG, 4 later developed seizures, or .0139% (4/28627). After review of the value of the EEG as a screening tool, the US Navy now uses EEG only for certain clinical indications (head injury, unexplained loss of consciousness, family history of epilepsy, and abnormal neurological exam). Currently the US Navy does not use EEG for screening for any flight applicant without a neurologic indication. In the US Navy, an electroencephalographic pattern is determined to be epileptiform by a neurologist.

Clark, Jonathan B.; Riley, Terrence

2001-01-01

327

Functional coupling of sensorimotor and associative areas during a catching ball task: a qEEG coherence study  

PubMed Central

Background Catching an object is a complex movement that involves not only programming but also effective motor coordination. Such behavior is related to the activation and recruitment of cortical regions that participates in the sensorimotor integration process. This study aimed to elucidate the cortical mechanisms involved in anticipatory actions when performing a task of catching an object in free fall. Methods Quantitative electroencephalography (qEEG) was recorded using a 20-channel EEG system in 20 healthy right-handed participants performed the catching ball task. We used the EEG coherence analysis to investigate subdivisions of alpha (8-12 Hz) and beta (12-30 Hz) bands, which are related to cognitive processing and sensory-motor integration. Results Notwithstanding, we found the main effects for the factor block; for alpha-1, coherence decreased from the first to sixth block, and the opposite effect occurred for alpha-2 and beta-2, with coherence increasing along the blocks. Conclusion It was concluded that to perform successfully our task, which involved anticipatory processes (i.e. feedback mechanisms), subjects exhibited a great involvement of sensory-motor and associative areas, possibly due to organization of information to process visuospatial parameters and further catch the falling object.

2012-01-01

328

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.

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

2013-01-01

329

[Perioperative EEG monitoring: studies of the electrophysiological arousal mechanism].  

PubMed

Electroencephalogram recordings have been advocated for assessment of changes in cerebral function during anaesthesia. Controversy exists on the specificity of EEG parameters indicating depth of anaesthesia, because cortical electrical activity is modulated not only by drugs but also by a variety of exogenous and endogenous stimuli. In clinical practice, EEG measures often fail to accurately predict anaesthetic depth since the effects of nociceptive stimulation on the EEG are still not well defined. Previous reports indicate that in anaesthetised patients sensory stimulation may induce a shift to a dominant EEG frequency with faster waves similar to patterns seen during emergence from anaesthesia under certain circumstances. This electrophysiological arousal (EEG desynchronisation) may be associated with clinical arousal phenomena such as movement and increases in haemodynamic and respiratory activity. However, the mechanism of arousal during emergence from anaesthesia may be quite different from arousal reactions induced by noxious stimulation. Recent studies indicate that surgical stimulation can induce increases in slow wave EEG-activity ("reverse" or "paradoxical" arousal) associated with clinical arousal phenomena. Stimulus related delta patterns also were observed after acoustical or painful stimulation in head injured patients. The occurrence of slow EEG wave patterns may be related to functional blockade of the ascending activating system of the brain stem. In contrast, slowing of the EEG is comparable to EEG changes seen with increasing concentrations of anaesthetics. This indicates the difficulty to discriminate arousal phenomena from drug effects using EEG monitoring alone.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7999933

Bischoff, P

1994-10-01

330

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

331

Status of quantitative EEG (QEEG) in clinical practice, 1994.  

PubMed

Clinical quantitative EEG (qEEG) is a complex specialty that may include not only standard EEG but also digital ("paperless") EEG, topographic mapping, spectral analysis, spectral coherence, long latency and event related potentials (EP), significance probability mapping (SPM), dipole source localization methodology (DLM), and discriminant function analysis. There are three basic clinical uses: non-specific detection of organicity/encephalopathy, specific categorization of disease or clinical condition, and epileptic source localization. Extreme variations exist in the competency of laboratories practicing clinical qEEG; universally agreed upon standards of practice have not been established but there are a number of efforts to do so. As expected, the clinical value of qEEG to patients varies similarly. Criticisms of qEEG have now been answered: Color displays need not be deceptive. Statistical "capitalization upon chance" can be easily avoided. By training and with newer analytic procedures, artifacts can be recognized and often removed. Data based upon spectral analysis and EP can reliably classify clinical conditions thereby demonstrating a greater sensitivity to EEG/EP data than possible by conventional visual inspection. QEEG is clearly of clinical value when performed in concert with standard EEG and analyzed by clinicians with demonstrated competency in standard EEG followed by specialized training and demonstrated competency in qEEG. QEEG is not a simple substitute for conventional EEG and cannot be seen as a substitute for clinical competence. Although continuing to develop, qEEG technology has matured sufficiently and is now well established. Concerns regarding its clinical use have primarily resulted from its misapplication and misinterpretation stemming, largely, from inadequate personnel training and expertise. PMID:7813090

Duffy, F H; Hughes, J R; Miranda, F; Bernad, P; Cook, P

1994-10-01

332

EEG spectro-temporal modulation energy: a new feature for automated diagnosis of Alzheimer's disease.  

PubMed

There is recent indication that Alzheimer's disease (AD) can be characterized by atypical modulation of electrophysiological brain activity caused by fibrillar amyloid deposition in specific regions of the brain, such as those related to cognition and memory. In this paper, we propose to objectively characterize EEG sub-band modulation in an attempt to develop an automated noninvasive AD diagnostics tool. First, multi-channel full-band EEG signals are decomposed into five well-known frequency sub-bands: delta, theta, alpha, beta, and gamma. The temporal amplitude envelope of each sub-band is then computed via a Hilbert transformation. The proposed 'spectro-temporal modulation energy' feature measures the rate with which each sub-band is modulated. Modulation energy features are computed for 19 referential EEG signals and seven bipolar signals. Salient features are then selected and used to train four different classifiers, namely, support vector machines, logistic regression, classification and regression trees, and neural networks. Experiments with a database of 34 participants, 22 of which have been clinically diagnosed with probable-AD, show a neural network classifier achieving over 91% accuracy, thus significantly outperforming a classifier trained with conventional spectral-based features. PMID:22255174

Trambaiolli, Lucas R; Falk, Tiago H; Fraga, Francisco J; Anghinah, Renato; Lorena, Ana C

2011-01-01

333

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

334

Correlated Components of Ongoing EEG Point to Emotionally Laden Attention - A Possible Marker of Engagement?  

PubMed Central

Recent evidence from functional magnetic resonance imaging suggests that cortical hemodynamic responses coincide in different subjects experiencing a common naturalistic stimulus. Here we utilize neural responses in the electroencephalogram (EEG) evoked by multiple presentations of short film clips to index brain states marked by high levels of correlation within and across subjects. We formulate a novel signal decomposition method which extracts maximally correlated signal components from multiple EEG records. The resulting components capture correlations down to a one-second time resolution, thus revealing that peak correlations of neural activity across viewings can occur in remarkable correspondence with arousing moments of the film. Moreover, a significant reduction in neural correlation occurs upon a second viewing of the film or when the narrative is disrupted by presenting its scenes scrambled in time. We also probe oscillatory brain activity during periods of heightened correlation, and observe during such times a significant increase in the theta band for a frontal component and reductions in the alpha and beta frequency bands for parietal and occipital components. Low-resolution EEG tomography of these components suggests that the correlated neural activity is consistent with sources in the cingulate and orbitofrontal cortices. Put together, these results suggest that the observed synchrony reflects attention- and emotion-modulated cortical processing which may be decoded with high temporal resolution by extracting maximally correlated components of neural activity.

Dmochowski, Jacek P.; Sajda, Paul; Dias, Joao; Parra, Lucas C.

2012-01-01

335

Disturbed resting state EEG synchronization in bipolar disorder: A graph-theoretic analysis?  

PubMed Central

Disruption of functional connectivity may be a key feature of bipolar disorder (BD) which reflects disturbances of synchronization and oscillations within brain networks. We investigated whether the resting electroencephalogram (EEG) in patients with BD showed altered synchronization or network properties. Resting-state EEG was recorded in 57 BD type-I patients and 87 healthy control subjects. Functional connectivity between pairs of EEG channels was measured using synchronization likelihood (SL) for 5 frequency bands (?, ?, ?, ?, and ?). Graph-theoretic analysis was applied to SL over the electrode array to assess network properties. BD patients showed a decrease of mean synchronization in the alpha band, and the decreases were greatest in fronto-central and centro-parietal connections. In addition, the clustering coefficient and global efficiency were decreased in BD patients, whereas the characteristic path length increased. We also found that the normalized characteristic path length and small-worldness were significantly correlated with depression scores in BD patients. These results suggest that BD patients show impaired neural synchronization at rest and a disruption of resting-state functional connectivity.

Kim, Dae-Jin; Bolbecker, Amanda R.; Howell, Josselyn; Rass, Olga; Sporns, Olaf; Hetrick, William P.; Breier, Alan; O'Donnell, Brian F.

2013-01-01

336

High dose CART peptide induces abnormal EEG activity and behavioral seizures.  

PubMed

Cocaine- and amphetamine-regulated transcript (CART) peptides are neurotransmitters found throughout the nervous system and in the periphery. CART has an important role in the regulation of food intake, anxiety, endocrine function, and in mesolimbic-mediated reward and reinforcement. This short report casts light upon previous descriptions of presumed behavioral seizure and tremor activity following administration of CART into the central nervous system. By employing electroencephalographic (EEG) recordings, we document the state of cerebrocortical activity. We find that intracerebroventricular (icv) administration of 5 microg of CART 55-102 readily produces an abnormal EEG characterized initially by high amplitude hypersynchronous alpha in the 8-10 Hz range during behavioral wakefulness as manifest in both cortical and hippocampal theta EEG channels. This reliably progressed in three of three animals tested to unequivocal epileptiform activity accompanied by tremors and assumption of a rigid, tonic body posture. The neural substrates underlying this finding are unclear. This novel description of the epileptogenic quality of CART should lend caution to interpretations of the behaviors attributed to CART in other experimental paradigms. PMID:18178249

Keating, Glenda L; Kuhar, Michael J; Rye, David B

2008-04-01

337

Frequency domain models of the EEG.  

PubMed

The structure of the normal resting EEG crosspectrum SVV(omega) is analyzed using complex multivariate statistics. Exploratory data analysis with Principal Component Analysis (PCA) is followed by hypothesis testing and computer simulations related to possible neural generators. The SVV(omega) of 211 normal individuals (ages 5 to 97) may be decomposed into two types of processes: the xi process with spatial isotropicity reflecting diffuse, correlated cortical generators with radial symmetry, and processes that seem to be generated by more spatially concentrated, correlated sources. The latter are reflected as spectral peaks such as the process. The eigenvectors of the xi process are the Spherical Harmonic Functions which explains the recurring pattern of maps characteristic of the spatial PCA of qEEG data. A new method for estimating sources in the frequency domain which fits dipoles to the whole crosspectrum is applied to explain the characteristics of the localized sources. PMID:1510874

Valdés, P; Bosch, J; Grave, R; Hernandez, J; Riera, J; Pascual, R; Biscay, R

1992-01-01

338

Spatiotemporal analysis of prepyriform, visual, auditory, and somesthetic surface EEGs in trained rabbits.  

PubMed

1. Spatial ensemble averages were computed for 64 traces of electroencephalograms (EEGs) simultaneously recorded from 8 x 8 arrays over the epidural surfaces of the prepyriform cortex (PPC) and visual, somatic, and auditory cortices. They revealed a common waveform across each array. Examination of the spatial amplitude modulation (AM) of the waveform revealed classifiable spatial pattern in short time segments. The AM patterns varied within trials after presentation of identical conditioned stimuli, and also between trials with differing stimuli. 2. PPC EEGs revealed strong correlates with the respiratory rhythm; neocortical EEGs did not. 3. Time ensemble averaging of the PPC EEG attenuated the oscillatory bursts, indicating that olfactory gamma oscillations (20-80 Hz) were not phase-locked to the times of stimulus delivery but instead to inhalations. Time ensemble averages of neocortical recordings across trials revealed average evoked potentials starting 30-50 ms after the arrival of the stimulus. 4. Average temporal fast Fourier transform (FFT) power spectral densities (PSDs) from pre- and poststimulus PPC EEG segments revealed a peak of gamma activity in olfactory bursts. 5. The logarithm of the average temporal FFT PSDs from pre- and poststimulus neocortical EEG segments, when plotted against log frequency, revealed 1/f-type spectra in both pre- and poststimulus segments for negative/aversive conditioned stimuli (CS-) and positive/rewarding conditioned stimuli (CS+). The alpha'- and beta'-coefficients from the regression of Eq. 2 onto the average PSDs were significantly different between pre- and poststimulus segments, owing to the evoked potentials, but not between CS- and CS+ stimulus segments. 6. Spatiotemporal patterns were invariant over all frequency bins in the 1/f domain (20-100 Hz). Spatiotemporal patterns in the 2- to 20-Hz domain progressively differed from the invariant patterns with decreasing frequency. 7. In the spatial frequency domain, the logarithm of the average spatial FFT power spectra from pre- and poststimulus neocortical EEG segments, when plotted against the log spatial frequency, fell monotonically from the maximum at the lowest spatial frequency, downwardly curving to a linear 1/f spectral domain. This curve in the 1/f spectral domain extended from 0.133 to 0.880 cycles/mm in the PPC and from 0.095 to 0.624 cycles/mm in the neocortices. 8. Methods of FFT and principal component analysis (PCA) EEG decomposition were used to extract the broad-spectrum waveform common to all 64 EEGs from an array. AM patterns for the FFT and PCA components were derived by regression. They were shown by cross-correlation to yield spatial patterns that were equivalent to each other and to AM patterns from calculation of the 64 root-mean-square amplitudes of the segments. 9. Each spatial AM pattern was expressed by a 1 x 64 column vector and a point in 64-space. Similar patterns formed clusters, and dissimilar patterns gave multiple clusters. A statistical test was devised to evaluate dissimilarity by a Euclidean distance metric in 64-space. 10. Significant spatial pattern classification of CS- versus CS+ trials (below the 1% confidence limit for 20 of each) was found in discrete temporal segments of poststimulus data after digital temporal and spatial filter optimization. 11. Varying the analysis window duration from 10 to 500 ms yielded a window length of 120 ms as optimal for pattern classification. A 120-ms window was subsequently stepped across each record in overlapping intervals of 20 ms. Windows in which episodic, significant CS+/CS- differences occurred lasted 50-200 ms and were separated by 100-200 ms in the poststimulus period. 12. Neocortical spatial patterns changed under reinforcement contingency reversal, showing a lack of invariance in respect to stimuli and a dependence on context and learning, as previously found for the olfactory bulb and PPC. PMID:8836241

Barrie, J M; Freeman, W J; Lenhart, M D

1996-07-01

339

Detection of EEG electrodes in brain volumes.  

PubMed

This paper presents a method to detect 128 EEG electrodes in image study and to merge with the Nuclear Magnetic Resonance volume for better diagnosis. First we propose three hypotheses to define a specific acquisition protocol in order to recognize the electrodes and to avoid distortions in the image. In the second instance we describe a method for segmenting the electrodes. Finally, registration is performed between volume of the electrodes and NMR. PMID:21095810

Graffigna, Juan P; Gómez, M Eugenia; Bustos, José J

2010-01-01

340

Frontal midline EEG dynamics during working memory  

Microsoft Academic Search

We show that during visual working memory, the electroencephalographic (EEG) process producing 5–7 Hz frontal midline theta (fm?) activity exhibits multiple spectral modes involving at least three frequency bands and a wide range of amplitudes. The process accounting for the fm? increase during working memory was separated from 71-channel data by clustering on time\\/frequency transforms of components returned by independent

Julie Onton; Arnaud Delorme; Scott Makeig

2005-01-01

341

EEG Quality:The Image Acquisition Artefact  

Microsoft Academic Search

\\u000a In this chapter, we focus on the artefacts that arise in the EEG during the fMRI acquisition process. Functional MRI using\\u000a echo planar imaging (EPI) sequences involves the application of rapidly varying magnetic field gradients for spatial encoding\\u000a of the MR signal and radiofrequency (RF) pulses for spin excitation (see the chapter “The Basics of Functional Magnetic Resonance\\u000a Imaging”). Early

Petra Ritter; Robert Becker; Frank Freyer; Arno Villringer

342

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.

Nombela, Cristina; Nombela, Manuel; Castell, Pedro; Garcia, Teodoro; Lopez-Coronado, Juan; Herrero, Maria Trinidad

2014-01-01

343

A decision support framework for the discrimination of children with controlled epilepsy based on EEG analysis  

PubMed Central

Background In this work we consider hidden signs (biomarkers) in ongoing EEG activity expressing epileptic tendency, for otherwise normal brain operation. More specifically, this study considers children with controlled epilepsy where only a few seizures without complications were noted before starting medication and who showed no clinical or electrophysiological signs of brain dysfunction. We compare EEG recordings from controlled epileptic children with age-matched control children under two different operations, an eyes closed rest condition and a mathematical task. The aim of this study is to develop reliable techniques for the extraction of biomarkers from EEG that indicate the presence of minor neurophysiological signs in cases where no clinical or significant EEG abnormalities are observed. Methods We compare two different approaches for localizing activity differences and retrieving relevant information for classifying the two groups. The first approach focuses on power spectrum analysis whereas the second approach analyzes the functional coupling of cortical assemblies using linear synchronization techniques. Results Differences could be detected during the control (rest) task, but not on the more demanding mathematical task. The spectral markers provide better diagnostic ability than their synchronization counterparts, even though a combination (or fusion) of both is needed for efficient classification of subjects. Conclusions Based on these differences, the study proposes concrete biomarkers that can be used in a decision support system for clinical validation. Fusion of selected biomarkers in the Theta and Alpha bands resulted in an increase of the classification score up to 80% during the rest condition. No significant discrimination was achieved during the performance of a mathematical subtraction task.

2010-01-01

344

EEG, auditory evoked potentials and evoked rhythmicities in three-year-old children.  

PubMed

According to our working hypothesis, the resonance properties of the brain systems play an important role in internal brain communications (e.g., Ba?ar, 1992; Ba?ar, Ba?ar-Eroglu, Demiralp & Schürmann, 1992). It was assumed that evoked potentials (EPs) reflect brain resonance properties, showing enhancement, time and frequency-locking during the poststimulus period. All these phenomena might be referred to the spontaneous (intrinsic) EEG rhythms according to the excitability rule and the related concept of brain system response susceptibility: a brain system could react to internal or external stimuli producing those rhythms or frequency components, which have already been present in intrinsic or spontaneous activity (Ba?ar, 1980). In order to test the hypothesis of response susceptibility, in the present paper we used an natural model--3-year-old children--to investigate how brain systems respond to external stimulation if their spontaneous rhythms are different in comparison to the spontaneous EEG rhythms in adults. For that purpose we used a combined time and frequency domain approach. The spectral characteristics of the spontaneous EEGs as well as the frequency components of auditory EPs elicited under identical auditory stimulation in 3-year-old children and adults aged 20-22 years were compared. Our observations support the hypothesis for response susceptibility; if in a given frequency channel the spontaneous brain rhythms are missing, they are also absent in the evoked and induced rhythmicities and vice versa: children at 3 years do not create alpha resonance upon sensory stimulation while they do not have developed EEG rhythms in the range of 8-15 Hz. Elicited under identical experimental conditions (auditory stimulation with fixed stimulus parameters) children and adult evoked rhythms differ. It was concluded that the AEPs recorded in 3-year-old children might be regarded mainly as a superposition of rhythmicities in delta and theta ranges. These rhythmicities are prolonged and delayed in comparison to the corresponding rhythms in adults. PMID:8050865

Ba?ar-Eroglu, C; Kolev, V; Ritter, B; Aksu, F; Ba?ar, E

1994-04-01

345

Integrating eye-tracking and wireless Electroencephalogram (EEG) in consumer neuroscience.  

PubMed

Consumer neuroscience addresses marketing relevant problems through the integration and application of neuroscientific theories, concepts, findings and methods to the research discipline of consumer behavior. The key contribution of this paper is to complement the advancement of traditional consumer research through the investigation of the patterns of interdependency between the Electroencephalogram (EEG) signals from the different brain regions while participants undertook a choice task designed to elicit preferences for a marketing product (crackers). Specifically, the task required participants to choose their preferred crackers described by shape (square, triangle, round), flavor (wheat, dark rye, plain) and topping (salt, poppy, no topping).We analyze the Electroencephalogram (EEG) signals collected from the different brain regions using the commercially available 14 channel Emotiv EPOC wireless EEG headset and relate the EEG data to the specific choice options with a Tobii X60 eye tracker. Fifteen participants were recruited for this experiment and were shown 57 choice sets; each choice set described three choice options. The patterns of cortical activity were obtained in the five principal frequency bands, Delta (0 - 4 Hz), Theta (3 - 7 Hz), Alpha (8 - 12 Hz), Beta (13 - 30 Hz), and Gamma (30 - 40 Hz). Our results indicate significant phase synchronization between the left and right frontal and occipital regions indicating interhemispheric communications during the choice task. Our experimental results also show that participants spent more time looking at the non-preferred items in each choice set at the beginning of the experiment (exploration mode), while reducing that time progressively to indicate significant amount of cognitive processing assigned to preferred items (exploitation mode). PMID:24111337

Khushaba, Rami N; Wise, Chelsea; Kodagoda, Sarath; Louviere, Jordan

2013-01-01

346

Sleep stage classification based on EEG Hilbert-Huang transform  

Microsoft Academic Search

The aim of this work is to propose an automatic sleep stage classification technique of electroencephalogram's signals (EEG) using Hilbert-Huang transform. EEG signals are analyzed with the Hilbert-Huang transform, instantaneous frequency with the physical meaning is obtained; The energy-frequency distribution of EEG was used as features parameters for each sleep stage; Ultimately using nearest neighbor method for pattern classification complete

Yi Li; Fan Yingle; Li Gu; Tong Qinye

2009-01-01

347

Using EEG to Study Cognitive Development: Issues and Practices  

PubMed Central

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 research. We also list best practices for incorporating this methodology into the study of early cognitive processes. Consideration of these issues is critical for making an informed decision regarding implementation of EEG methodology.

Bell, Martha Ann; Cuevas, Kimberly

2012-01-01

348

ERPs correlates of EEG relative beta training in ADHD children  

Microsoft Academic Search

Eighty-six children (ages 9–14) with attention deficit hyperactivity disorder (ADHD) participated in this study. Event-related potentials (ERPs) were recorded in auditory GO\\/NOGO task before and after 15–22 sessions of EEG biofeedback. Each session consisted of 20 min of enhancing the ratio of the EEG power in 15–18 Hz band to the EEG power in the rest of spectrum, and 7–10

Jury D. Kropotov; Vera A. Grin-Yatsenko; Valery A. Ponomarev; Leonid S. Chutko; Elena A. Yakovenko; Inna S. Nikishena

2005-01-01

349

EEG source analysis using space mapping techniques  

NASA Astrophysics Data System (ADS)

The electroencephalogram (EEG) measures potential differences, generated by electrical activity in brain tissue, between scalp electrodes. The EEG potentials can be calculated by the quasi-static Poisson equation in a certain head model. It is well known that the electrical dipole (source) which best fits the measured EEG potentials is obtained by an inverse problem. The dipole parameters are obtained by finding the global minimum of the relative residual energy (RRE). For the first time, the space mapping technique (SM technique) is used for minimizing the RRE. The SM technique aims at aligning two different simulation models: a fine model, accurate but CPU-time expensive, and a coarse model, computationally fast but less accurate than the fine one. The coarse model is a semi-analytical model, the so-called three-shell concentric sphere model. The fine model numerically solves the Poisson equation in a realistic head model. If we use the aggressive space mapping (ASM) algorithm, the errors on the dipole location are too large. The hybrid aggressive space mapping (HASM) on the other hand has better convergence properties, yielding a reduction in dipole location errors. The computational effort of HASM is greater than ASM but smaller than using direct optimization techniques.

Crevecoeur, G.; Hallez, H.; van Hese, P.; D'Asseler, Y.; Dupre, L.; van de Walle, R.

2008-06-01

350

Ictal EEG changes with corpus callosum section.  

PubMed

Corpus callosum section diminishes but does not completely abolish secondary bilaterally synchronous interictal EEG discharges, yet often causes cessation of generalized seizures. The effects of corpus callosum section on ictal EEG patterns have not been described. We contrasted ictal EEG patterns before and after anterior callosotomy in 18 patients and before and after total callosotomy in 10 patients. Bilaterally synchronous seizure onset was disrupted in 5 of 11 anterior section patients and 5 of 5 total section patients. Seven of 18 anterior section patients and 5 of 10 total section patients had more localized seizure onset after the procedure; localization to the frontal lobe was observed after anterior or total section, but only total section patients had newly demonstrated posterior locations of seizure onset. These data suggest that the mechanisms by which bilaterally synchronous interictal and ictal discharges are generated differ. Although brainstem or diencephalic structures may contribute to formation of interictal bilateral synchrony, the corpus callosum may be the only pathway used in producing apparent bilateral synchronous seizure onset in patients with secondarily generalized seizures. PMID:8504788

Spencer, S S; Katz, A; Ebersole, J; Novotny, E; Mattson, R

1993-01-01

351

Lasting Modulation Effects of rTMS on Neural Activity and Connectivity as Revealed by Resting-State EEG.  

PubMed

The long-lasting neuromodulatory effects of repetitive transcranial magnetic stimulation (rTMS) are of great interest for therapeutic applications in various neurological and psychiatric disorders, due to which functional connectivity among brain regions is profoundly disturbed. Classic TMS studies selectively alter neural activity in specific brain regions and observe neural activity changes on nonperturbed areas to infer underlying connectivity and its changes. Less has been indicated in direct measures of functional connectivity and/or neural network and on how connectivity/network alterations occur. Here, we developed a novel analysis framework to directly investigate both neural activity and connectivity changes induced by rTMS from resting-state EEG (rsEEG) acquired in a group of subjects with a chronic disorder of imbalance, known as the mal de debarquement syndrome (MdDS). Resting-state activity in multiple functional brain areas was identified through a data-driven blind source separation analysis on rsEEG data, and the connectivity among them was characterized using a phase synchronization measure. Our study revealed that there were significant long-lasting changes in resting-state neural activity, in theta, low alpha, and high alpha bands and neural networks in theta, low alpha, high alpha and beta bands, over broad cortical areas 4 to 5 h after the last application of rTMS in a consecutive five-day protocol. Our results of rsEEG connectivity further indicated that the changes, mainly in the alpha band, over the parietal and occipital cortices from pre- to post-TMS sessions were significantly correlated, in both magnitude and direction, to symptom changes in this group of subjects with MdDS. This connectivity measure not only suggested that rTMS can generate positive treatment effects in MdDS patients, but also revealed new potential targets for future therapeutic trials to improve treatment effects. It is promising that the new connectivity measure from rsEEG can be used to understand the variability in treatment response to rTMS in brain disorders with impaired functional connectivity and, eventually, to determine individually tailored stimulation parameters and treatment procedures in rTMS. PMID:24686227

Ding, Lei; Shou, Guofa; Yuan, Han; Urbano, Diamond; Cha, Yoon-Hee

2014-07-01

352

Familial clustering and DRD4 effects on EEG Measures in multiplex families with Attention-Deficit Hyperactivity Disorder  

PubMed Central

Objective The current study tests encephalogram (EEG) measures as a potential endophenotype for Attention-Deficit Hyperactivity Disorder (ADHD) by examining sibling and parent-offspring similarity, familial clustering with the disorder, and association with the dopamine receptor D4 (DRD4) candidate gene. Method The sample consists of 531 participants (191 parents and 340 children) from 132 multiplex families with ADHD who participated in a larger genetics study. All members of the families underwent extensive assessment including semi-structured diagnostic interviews and EEG recording. Results Strong sibling similarity and parent-offspring correlations in EEG power emerged, suggesting high trait heritability. Among children, increased theta power was observed among children with ADHD when compared to unaffected children and there were no differences according to ADHD subtype. Within the parent sample, ADHD diagnostic status and ADHD subtype group differences emerged in the theta, alpha and beta frequency bands. DRD4 effects for both parents and children were apparent in the beta frequency band and for children only in the theta frequency band. Conclusions This study suggests that EEG measures are a promising avenue of study in the search for putative endophenotypes for ADHD and that variability at the DRD4 gene may contribute to this endophenotype.

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

2010-01-01

353

Alpha Rhythms in Audition: Cognitive and Clinical Perspectives  

PubMed Central

Like the visual and the sensorimotor systems, the auditory system exhibits pronounced alpha-like resting oscillatory activity. Due to the relatively small spatial extent of auditory cortical areas, this rhythmic activity is less obvious and frequently masked by non-auditory alpha-generators when recording non-invasively using magnetoencephalography (MEG) or electroencephalography (EEG). Following stimulation with sounds, marked desynchronizations can be observed between 6 and 12?Hz, which can be localized to the auditory cortex. However knowledge about the functional relevance of the auditory alpha rhythm has remained scarce so far. Results from the visual and sensorimotor system have fuelled the hypothesis of alpha activity reflecting a state of functional inhibition. The current article pursues several intentions: (1) Firstly we review and present own evidence (MEG, EEG, sEEG) for the existence of an auditory alpha-like rhythm independent of visual or motor generators, something that is occasionally met with skepticism. (2) In a second part we will discuss tinnitus and how this audiological symptom may relate to reduced background alpha. The clinical part will give an introduction into a method which aims to modulate neurophysiological activity hypothesized to underlie this distressing disorder. Using neurofeedback, one is able to directly target relevant oscillatory activity. Preliminary data point to a high potential of this approach for treating tinnitus. (3) Finally, in a cognitive neuroscientific part we will show that auditory alpha is modulated by anticipation/expectations with and without auditory stimulation. We will also introduce ideas and initial evidence that alpha oscillations are involved in the most complex capability of the auditory system, namely speech perception. The evidence presented in this article corroborates findings from other modalities, indicating that alpha-like activity functionally has an universal inhibitory role across sensory modalities.

Weisz, Nathan; Hartmann, Thomas; Muller, Nadia; Lorenz, Isabel; Obleser, Jonas

2011-01-01

354

EEG asymmetry in borderline personality disorder and depression following rejection.  

PubMed

Borderline personality disorder (BPD) and major depressive disorder (MDD) share numerous features, including dysphoric affect, irritability, suicidality, and a heightened sensitivity to perceived interpersonal rejection. However, these disorders are associated with divergent profiles of reactivity to rejection: Individuals with MDD are more likely to respond with withdrawal and isolation, and those with BPD appear to respond with increased approach behaviors and greater hostility. Potential mechanisms underlying these divergent patterns of response have not been elaborated. The goal of the present study was to assess whether prefrontal cortical asymmetry is associated with these behavioral profiles. EEG alpha activity was recorded at baseline and after individuals with BPD, MDD and healthy controls (HCs) participated in a rejection task. Although no differences were found at baseline, results demonstrated that following rejection, individuals with BPD showed greater left cortical activation, consistent with approach motivation, whereas those with MDD showed greater right cortical activation, consistent with withdrawal motivation. HCs evidenced a more balanced cortical profile, as hypothesized. Although BPD and MDD are highly comorbid, are easily confused, and are phenomenologically similar in a number of ways, individuals with these two disorders respond in very different ways to perceived rejection. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24364503

Beeney, Joseph E; Levy, Kenneth N; Gatzke-Kopp, Lisa M; Hallquist, Michael N

2014-04-01

355

Preliminary Study: The Comparison between Hands-Free and Handheld 3G Mobile Phone on Alpha Brainwave  

Microsoft Academic Search

This paper presents a preliminary study on the comparison between hands-free and handheld 3G mobile phone on alpha brainwave signal for thirty samples. The resting alpha brainwave activities were recorded using EEG for three stages which are before, during and after calls. The data analysis involved correlation between left and right brainwaves signals using SPSS (Statistical Package for the Social

Ros Shilawani S. Abdul Kadir; Noor Atisha Aliyasak; Zunairah Hj Murat; Rozita Jailani

2012-01-01

356

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.

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

357

Noisy Galvanic Vestibular Stimulation Modulates the Amplitude of EEG Synchrony Patterns  

PubMed Central

Noisy galvanic vestibular stimulation has been associated with numerous cognitive and behavioural effects, such as enhancement of visual memory in healthy individuals, improvement of visual deficits in stroke patients, as well as possibly improvement of motor function in Parkinson’s disease; yet, the mechanism of action is unclear. Since Parkinson’s and other neuropsychiatric diseases are characterized by maladaptive dynamics of brain rhythms, we investigated whether noisy galvanic vestibular stimulation was associated with measurable changes in EEG oscillatory rhythms within theta (4–7.5 Hz), low alpha (8–10 Hz), high alpha (10.5–12 Hz), beta (13–30 Hz) and gamma (31–50 Hz) bands. We recorded the EEG while simultaneously delivering noisy bilateral, bipolar stimulation at varying intensities of imperceptible currents – at 10, 26, 42, 58, 74 and 90% of sensory threshold – to ten neurologically healthy subjects. Using standard spectral analysis, we investigated the transient aftereffects of noisy stimulation on rhythms. Subsequently, using robust artifact rejection techniques and the Least Absolute Shrinkage Selection Operator regression and cross-validation, we assessed the combinations of channels and power spectral features within each EEG frequency band that were linearly related with stimulus intensity. We show that noisy galvanic vestibular stimulation predominantly leads to a mild suppression of gamma power in lateral regions immediately after stimulation, followed by delayed increase in beta and gamma power in frontal regions approximately 20–25 s after stimulation ceased. Ongoing changes in the power of each oscillatory band throughout frontal, central/parietal, occipital and bilateral electrodes predicted the intensity of galvanic vestibular stimulation in a stimulus-dependent manner, demonstrating linear effects of stimulation on brain rhythms. We propose that modulation of neural oscillations is a potential mechanism for the previously-described cognitive and motor effects of vestibular stimulation, and noisy galvanic vestibular stimulation may provide an additional non-invasive means for neuromodulation of functional brain networks.

Kim, Diana J.; Yogendrakumar, Vignan; Chiang, Joyce; Ty, Edna; Wang, Z. Jane; McKeown, Martin J.

2013-01-01

358

Alpha rhythm and the pineal gland.  

PubMed

Alpha rhythm is classically described as a bilateral posterior rhythm of substantially constant frequency in the range of 8-13 Hz which is enhanced by mental relaxation and blocked by attention. Since the full expression of alpha rhythm has been shown to occur coincident with puberty, it is possible that the establishment of alpha rhythm is subject to neuroendocrine influences which govern psychosexual maturation. There is ample evidence to indicate that the pineal gland is implicated in cerebral maturation and psychosexual development. Nocturnal plasma melatonin levels have been shown to decline progressively throughout childhood reaching a nadir at puberty. Since administration of melatonin has been reported to block alpha rhythm, it is proposed that the progressive decline in melatonin secretion during childhood facilitates the maturation of the alpha rhythm. Consequently, the presence of alpha rhythm could be used as a neurophysiological marker for the activity of the pineal gland and disorders associated with absent or delayed maturation of the alpha rhythm such as autism, dyslexia, personality disorders, epilepsy, Tourette's syndrome, and schizophrenia might be related to disturbances of pineal melatonin functions in early life. Moreover, since the EEG patterns associated with cerebral immaturity (i.e., slowing, absence of alpha activity) are more pronounced in the left hemisphere, this hypothesis implies differential influence of the pineal gland on hemispheric maturation potentially accounting for the vulnerability of the left hemisphere to cerebral insults. PMID:1304557

Sandyk, R

1992-04-01

359

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.

Beniczky, Sandor; Aurlien, Harald; Br?gger, Jan C; Fuglsang-Frederiksen, Anders; Martins-da-Silva, Antonio; Trinka, Eugen; Visser, Gerhard; Rubboli, Guido; Hjalgrim, Helle; Stefan, Hermann; Rosen, Ingmar; Zarubova, Jana; Dobesberger, Judith; Alving, J?rgen; Andersen, Kjeld V; Fabricius, Martin; Atkins, Mary D; Neufeld, Miri; Plouin, Perrine; Marusic, Petr; Pressler, Ronit; Mameniskiene, Ruta; Hopfengartner, Rudiger; Emde Boas, Walter; Wolf, Peter

2013-01-01

360

Oscillatory EEG correlates of arithmetic strategy use in addition and subtraction.  

PubMed

Adults use different strategies in mental arithmetic. For example, they directly retrieve the answer from memory or calculate by means of procedural strategies. Despite growing insight into the hemodynamic and electrophysiological correlates of these strategies, the functional changes in the oscillatory brain dynamics during the use of these strategies remain unknown. In the present high-resolution electroencephalography (EEG) study, we analysed event-related synchronisation (ERS) and desynchronisation (ERD) in the theta and alpha bands while participants solved addition and subtraction problems, which displayed a high probability of retrieval or procedural strategy use. Findings revealed that arithmetic fact retrieval is reflected in left-hemispheric ERS in the theta band, whereas the application of procedural strategies is accompanied by bilateral parietooccipital ERD in the alpha band. The topographical and frequency specificity of the strategy effects provides a start for the development of electrophysiological indices of strategy use in arithmetic. PMID:19452143

De Smedt, Bert; Grabner, Roland H; Studer, Bettina

2009-06-01

361

A neurophysiological signature of motivational incongruence: EEG changes related to insufficient goal satisfaction.  

PubMed

Human behavior and psychological functioning is motivated and guided by individual goals. Motivational incongruence refers to states of insufficient goal satisfaction and is tightly related to psychological problems and even psychopathology. In the present study, individual levels of motivational incongruence were assessed with the incongruence-questionnaire (INC) in a healthy sample. In addition, multi-channel resting-state EEG was measured. Individual variations of EEG synchronization and spectral power were related to individual levels of motivational incongruence. For significant correlations, the relation to intracerebral sources of electrical brain activity was investigated with sLORETA. The results indicate that, even in a healthy sample with rather low degrees of motivational incongruence, this insufficient goal satisfaction is related to consistent changes in resting state brain activity. Upper Alpha band attenuation seems to be most indicative of increased levels of motivational incongruence. This is reflected not only in significantly reduced functional connectivity, but also in changes regarding the level of brain activation, as indicated by significant effects in the spectral power and LORETA analyses. Results are related to research investigating the upper Alpha band and are discussed in the framework of Grawe's consistency theory. PMID:23644257

Stein, Maria; Egenolf, Yvonne; Dierks, Thomas; Caspar, Franz; Koenig, Thomas

2013-07-01

362

Interhemispheric EEG coherence is reduced in auditory cortical regions in schizophrenia patients with auditory hallucinations.  

PubMed

Central auditory processing has been reported to be impaired in schizophrenia patients who experience auditory hallucinations, and interhemispheric transfer in auditory circuits may be compromised. In this study, we used EEG spectral coherence to examine interhemispheric connectivity between cortical areas known to be important in the processing of auditory information. Coherence was compared across three subject groups: schizophrenia patients with a recent history of auditory hallucinations (AH), schizophrenia patients who did not experience auditory hallucinations (nonAH), and healthy controls (HC). Subjects listened to pure tone and word stimuli while EEG was recorded continuously. Upper alpha and upper beta band coherence was calculated from six pairs of electrodes located over homologous auditory areas in the left and right cerebral hemispheres. Significant between-group differences were found on four electrode pairs (C3-C4, C5-C6, Ft7-Ft8 and Cp5-Cp6) in the upper alpha band. Relative to both the HC and nonAH groups, coherence was lower in the AH patients, consistent with the hypothesis that interhemispheric connectivity is reduced in these patients. PMID:23707337

Henshall, Katherine R; Sergejew, Alex A; Rance, Gary; McKay, Colette M; Copolov, David L

2013-07-01

363

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.

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

2014-01-01

364

Developmental trajectories of resting EEG power: an endophenotype of autism spectrum disorder.  

PubMed

Current research suggests that autism spectrum disorder (ASD) is characterized by asynchronous neural oscillations. However, it is unclear whether changes in neural oscillations represent an index of the disorder or are shared more broadly among both affected and unaffected family members. Additionally, it remains unclear how early these differences emerge in development and whether they remain constant or change over time. In this study we examined developmental trajectories in spectral power in infants at high- or low-risk for ASD. Spectral power was extracted from resting EEG recorded over frontal regions of the scalp when infants were 6, 9, 12, 18 and 24 months of age. We used multilevel modeling to assess change over time between risk groups in the delta, theta, low alpha, high alpha, beta, and gamma frequency bands. The results indicated that across all bands, spectral power was lower in high-risk infants as compared to low-risk infants at 6-months of age. Furthermore high-risk infants showed different trajectories of change in spectral power in the subsequent developmental window indicating that not only are the patterns of change different, but that group differences are dynamic within the first two years of life. These findings remained the same after removing data from a subset of participants who displayed ASD related behaviors at 24 or 36 months. These differences in the nature of the trajectories of EEG power represent important endophenotypes of ASD. PMID:22745707

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

2012-01-01

365

[Evidence of a pharmacokinetic-pharmacodynamic relationship between pharmaco-EEG in healthy subjects after administration of cyclandelate].  

PubMed

In an open randomized cross-over study 800 mg cyclandelate (Natil, CAS 456-59-7) was applicated to 24 young, male volunteers. Before and during 24 h after application of a single dose a 17-channel, quantitative topographical pharmaco-EEG was recorded. A significant increase of the spectral power density was observed in the alpha 2, beta 1 and beta 2 frequency bands starting 2 h after application until 4.5 h. The increase in beta 1 and beta 2 power was observed in the parietocentral area of the cortex. The difference between the circadian development of the EEG power and the development after medication was obvious after 3 until 4.5 h. For the beta frequencies only a weak statistical confirmation could be obtained, but for the alpha 2 frequency a significant difference between the circadian and the EEG power under cyclandelate was found using the sign test. Altogether a quantitative effect on brain activity was detected after oral application of cyclandelate, reaching its maximum before the blood concentration of the metabolites cyclandic glucuronide and mandelic acid reached their peak heights. PMID:7986255

Dimpfel, W; Schober, F; Wedekind, W; Kleinbloesem, C; Coors, C

1994-09-01

366

A 200 W Eight-Channel EEG Acquisition ASIC for Ambulatory EEG Systems  

Microsoft Academic Search

The growing interest toward the improvement of patients' quality of life and the use of medical signals in nonmedical applications such as entertainment, sports, and brain-computerinterfaces, requires the implementation of miniaturized and wireless biopotential acquisition systems with ultralow power dissipation. Therefore, this paper presents the implementation of a complete EEG acquisition ASIC tailored towards the needs of such applications, i.e.,

Refet Firat Yazicioglu; Patrick Merken; Robert Puers; Chris Van Hoof

2008-01-01

367

Cortical Networks Generating Movement-Related EEG Rhythms in Alzheimer's Disease: An EEG Coherence Study  

Microsoft Academic Search

Patients with mild Alzheimer's disease (AD) present with abnormally strong values of frontal and ipsilateral central sensorimotor rhythms. The authors tested 2 working hypotheses of the related electroencephalographic (EEG) coherence: disconnection, defined as a sign of a reduced coordination within the frontoparietal and interhemispheric networks, and cooperation, defined as a reflection of the reorganization of the brain sensorimotor networks. Results

Claudio Babiloni; Carlo Miniussi; Davide V. Moretti; Fabrizio Vecchio; Serenella Salinari; Giovanni Frisoni; Paolo Maria Rossini

2004-01-01

368

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

369

EOG and Delta Rhythmicity in Human Sleep EEG.  

National Technical Information Service (NTIS)

The use of electroencephalogram (EEG) is accepted as the only objective method of studying sleep. However, EEG sleep study may not be feasible, although it would be highly desirable, in some non-laboratory operational environments due to difficulties in E...

R. Hilbert P. Naitoh

1972-01-01

370

Concepts and applications of EEG analysis in aviation performance evaluation  

Microsoft Academic Search

Quantitative studies of the human EEG during signal detection, flight simulation and actual flight performance tasks are reviewed here from the perspective of basic animal research on the neurophysiological and functional correlates of relevant rhythmic patterns. Evidence is examined which relates distinct EEG frequency changes to psychomotor behavior, signal processing and intrinsic attentional modulation during complex performance. Findings indicate that

M. B. Sterman; C. A. Mann

1995-01-01

371

Epileptic EEG detection using neural networks and post-classification  

Microsoft Academic Search

Electroencephalogram (EEG) has established itself as an important means of identifying and analyzing epileptic seizure activity in humans. In most cases, identification of the epileptic EEG signal is done manually by skilled professionals, who are small in number. In this paper, we try to automate the detection process. We use wavelet transform for feature extraction and obtain statistical parameters from

Lalit M. Patnaik; Ohil K. Manyam

2008-01-01

372

EEG brainwave pattern for smoking behaviour after Horizontal Rotation treatment  

Microsoft Academic Search

The main focus of this research is to analyze EEG signal of smokers after undergoing Horizontal Rotation (HR) treatment. 21 male smokers were sampled in this study. EEG data was captured before and after HR for 5 sessions. In addition, some demographic data were gathered from the samples to check their smoking habits. It was found that, HR significantly improves

Z. M. Hanafiah; K. F. M. Yunos; Z. H. Murat; M. N. Taib; S. Lias

2009-01-01

373

Multiclass Support Vector Machines for EEG-Signals Classification  

Microsoft Academic Search

In this paper, we proposed the multiclass support vector machine (SVM) with the error-correcting output codes for the multiclass electroencephalogram (EEG) signals classification problem. The probabilistic neural network (PNN) and multilayer perceptron neural network were also tested and benchmarked for their performance on the classification of the EEG signals. Decision making was performed in two stages: feature extraction by computing

Inan Güler; Elif Derya Übeyli

2007-01-01

374

EEG and evoked potentials in the intensive care unit  

Microsoft Academic Search

We review the principal aspects of EEG and evoked potential (EP) neuromonitoring in the intensive care unit. The electrophysiological methods allow functional assessment of comatose patients and can be used (a) as a help to diagnose the origin of coma, (b) as a means to predict outcome, and (c) for monitoring purposes. The combination of the EEG and long-, middle-,

J. M. Guérit

1999-01-01

375

The relationship between quantified EEG and skin conductance level  

Microsoft Academic Search

Electroencephalographic measures (EEG) and skin conductance level (SCL) respectively reflect cerebral cortical activity and sympathetic autonomic activity. Such central and autonomic activities associated with arousal generally have been studied separately, despite their potential to reflect complementary dimensions of reticular-thalamo-hypothalamo-cortical activating networks. In this study, we examined the relationship between cortical (19 EEG sites) and autonomic (SCL) activities recorded simultaneously in

C. L. Lim; R. J. Barry; E. Gordon; A. Sawant; C. Rennie; C. Yiannikas

1996-01-01

376

An empirical EEG analysis in brain death diagnosis for adults  

PubMed Central

Electroencephalogram (EEG) is often used in the confirmatory test for brain death diagnosis in clinical practice. Because EEG recording and monitoring is relatively safe for the patients in deep coma, it is believed to be valuable for either reducing the risk of brain death diagnosis (while comparing other tests such as the apnea) or preventing mistaken diagnosis. The objective of this paper is to study several statistical methods for quantitative EEG analysis in order to help bedside or ambulatory monitoring or diagnosis. We apply signal processing and quantitative statistical analysis for the EEG recordings of 32 adult patients. For EEG signal processing, independent component analysis (ICA) was applied to separate the independent source components, followed by Fourier and time-frequency analysis. For quantitative EEG analysis, we apply several statistical complexity measures to the EEG signals and evaluate the differences between two groups of patients: the subjects in deep coma, and the subjects who were categorized as brain death. We report statistically significant differences of quantitative statistics with real-life EEG recordings in such a clinical study, and we also present interpretation and discussions on the preliminary experimental results.

Cao, Jianting; Cao, Yang; Zhang, Yue; Gu, Fanji; Zhu, Guoxian; Hong, Zhen; Wang, Bin; Cichocki, Andrzej

2008-01-01

377

Discrete wavelet transform based seizure detection in newborns EEG signals  

Microsoft Academic Search

This paper proposes a novel method for detecting newborns seizure events from electroencephalogram (EEG) data. The detection scheme is based on the discrete wavelet transform (DWT) of the EEG signals. The number of zero-crossings, the average distance between adjacent zero-crossings, the number of extrema, and the average distance between adjacent extrema of the wavelet coefficients (WCs) of certain scales are

P. Zarjam; M. Mesbah

2003-01-01

378

Usefulness of video-EEG in the paediatric emergency department.  

PubMed

Over the past two decades the EEG has technically improved from the use of analog to digital machines and more recently to video-EEG systems. Despite these advances, recording a technically acceptable EEG in an electrically hostile environment such as the emergency department (ED) remains a challenge, particularly with infants or young children. In 1996, a meeting of French experts established a set of guidelines for performing an EEG in the ED based on a review of the available literature. The authors highlighted the most suitable indications for an emergency EEG including clinical suspicion of cerebral death, convulsive and myoclonic status epilepticus, focal or generalized relapsing convulsive seizures as well as follow-up of known convulsive patients. They further recommended emergency EEG in the presence of doubt regarding the epileptic nature of the presentation as well as during the initiation or modification of sedation following brain injury. Subsequently, proposals for expanding the use of EEG in emergency patients have been advocated including trauma, vascular and anoxic-ischemic injury due to cardiorespiratory arrest, postinfective encephalopathy and nonconvulsive status epilepticus. The aim of this review is to show the diagnostic importance of video-EEG, as well as highlighting the predictive prognostic factors for positive and negative outcomes, when utilized in the pediatric ED for seizures as well as other neurological presentations. PMID:24917085

Falsaperla, Raffaele; Striano, Pasquale; Parisi, Pasquale; Lubrano, Riccardo; Mahmood, Fahad; Pavone, Piero; Vitaliti, Giovanna

2014-07-01

379

A novel telemetry system for recording EEG in small animals  

Microsoft Academic Search

It has become increasingly evident that continuous EEG monitoring is necessary to observe the development of epilepsy in animals, and to determine the effect of drugs on spontaneous seizures. Telemetric recording systems have been increasingly used to monitor EEG in freely moving animals. One challenge faced by such systems is to monitor frequencies above 80Hz continuously for weeks. We present

Pishan Chang; Kevan S. Hashemi; Matthew C. Walker

2011-01-01

380

Detection of Spikes with Artificial Neural Networks Using Raw EEG  

Microsoft Academic Search

Artificial neural networks (ANN) using raw electroencephalogram (EEG) data were developed and tested off-line to detect transient epileptiform discharges (spike and spike\\/wave) and EMG activity in an ongoing EEG. In the present study, a feedforward ANN with a variable number of input and hidden layer units and two output units was used to optimize the detection system. The ANN system

Ö. Özdamar

1998-01-01

381

Quantitative EEG in hospital encephalopathy: review and microstate analysis.  

PubMed

Hospital-acquired encephalopathy is a widely prevalent disorder. The quantitative changes in EEG associated with this condition have long been noted, including slowing of the background frequency and changes in the frequency band power. EEG has had limited clinical use, despite its ability to continuously track clinical severity. We review the development of the use of EEG and particularly quantitative EEG in the assessment of hospital-acquired encephalopathy. Recent advances in EEG technology have included network and microstate analyses, and continuous EEG monitoring, leading to renewed interest in the use of quantitative EEG. We describe the development of microstate analysis that has allowed novel quantitative analysis of the resting state background. We examined the microstates of 16 inpatients with encephalopathy and 20 control patients. The global variance explained by the four standard resting microstates was smaller in patients with encephalopathy. This suggests a decrease in microstate stability, indicating a breakdown in the resting state network dynamics. Modern analysis and acquisition techniques hold the promise of renewed interest in quantitative EEG techniques in the assessment of hospital-acquired encephalopathy. PMID:24084185

Sarkis, Rani A; Lee, Jong Woo

2013-10-01

382

EEG Cartography of a Night of Sleep and Dreams  

Microsoft Academic Search

A night of sleep has been recorded under the conditions of a sleep laboratory. The subject was a woman of 55 years, well-trained in dream recall. The subject was awakened three times at the end of sleep cycles. EEG was monitored for 7 h with a 16-channel polygraph (REEGA 16, Alvar) connected to two systems of EEG cartography: minicomputers (HP

P. Etevenon; S. Guillou

1986-01-01

383

Wireless recording systems: from noninvasive EEG-NIRS to invasive EEG devices.  

PubMed

In this paper, we present the design and implementation of a wireless wearable electronic system dedicated to remote data recording for brain monitoring. The reported wireless recording system is used for a) simultaneous near-infrared spectrometry (NIRS) and scalp electro-encephalography (EEG) for noninvasive monitoring and b) intracerebral EEG (icEEG) for invasive monitoring. Bluetooth and dual radio links were introduced for these recordings. The Bluetooth-based device was embedded in a noninvasive multichannel EEG-NIRS system for easy portability and long-term monitoring. On the other hand, the 32-channel implantable recording device offers 24-bit resolution, tunable features, and a sampling frequency up to 2 kHz per channel. The analog front-end preamplifier presents low input-referred noise of 5 ? VRMS and a signal-to-noise ratio of 112 dB. The communication link is implemented using a dual-band radio frequency transceiver offering a half-duplex 800 kb/s data rate, 16.5 mW power consumption and less than 10(-10) post-correction Bit-Error Rate (BER). The designed system can be accessed and controlled by a computer with a user-friendly graphical interface. The proposed wireless implantable recording device was tested in vitro using real icEEG signals from two patients with refractory epilepsy. The wirelessly recorded signals were compared to the original signals recorded using wired-connection, and measured normalized root-mean square deviation was under 2%. PMID:23853301

Sawan, Mohamad; Salam, Muhammad T; Le Lan, Jérôme; Kassab, Amal; Gelinas, Sébastien; Vannasing, Phetsamone; Lesage, Frédéric; Lassonde, Maryse; Nguyen, Dang K

2013-04-01

384

Only Low Frequency Event-Related EEG Activity Is Compromised in Multiple Sclerosis: Insights from an Independent Component Clustering Analysis  

PubMed Central

Cognitive impairment (CI), often examined with neuropsychological tests such as the Paced Auditory Serial Addition Test (PASAT), affects approximately 65% of multiple sclerosis (MS) patients. The P3b event-related potential (ERP), evoked when an infrequent target stimulus is presented, indexes cognitive function and is typically compared across subjects' scalp electroencephalography (EEG) data. However, the clustering of independent components (ICs) is superior to scalp-based EEG methods because it can accommodate the spatiotemporal overlap inherent in scalp EEG data. Event-related spectral perturbations (ERSPs; event-related mean power spectral changes) and inter-trial coherence (ITCs; event-related consistency of spectral phase) reveal a more comprehensive overview of EEG activity. Ninety-five subjects (56 MS patients, 39 controls) completed visual and auditory two-stimulus P3b event-related potential tasks and the PASAT. MS patients were also divided into CI and non-CI groups (n?=?18 in each) based on PASAT scores. Data were recorded from 128-scalp EEG channels and 4 IC clusters in the visual, and 5 IC clusters in the auditory, modality were identified. In general, MS patients had significantly reduced ERSP theta power versus controls, and a similar pattern was observed for CI vs. non-CI MS patients. The ITC measures were also significantly different in the theta band for some clusters. The finding that MS patients had reduced P3b task-related theta power in both modalities is a reflection of compromised connectivity, likely due to demyelination, that may have disrupted early processes essential to P3b generation, such as orientating and signal detection. However, for posterior sources, MS patients had a greater decrease in alpha power, normally associated with enhanced cognitive function, which may reflect a compensatory mechanism in response to the compromised early cognitive processing.

Kiiski, Hanni; Reilly, Richard B.; Lonergan, Roisin; Kelly, Siobhan; O'Brien, Marie Claire; Kinsella, Katie; Bramham, Jessica; Burke, Teresa; O Donnchadha, Sean; Nolan, Hugh; Hutchinson, Michael; Tubridy, Niall; Whelan, Robert

2012-01-01

385

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.

2014-01-01

386

Tobacco Smoking Produces Widespread Dominant Brain Wave Alpha Frequency Increases  

PubMed Central

The major pharmacological ingredient in tobacco smoke is nicotine, a mild stimulant known to alter brain electrical activity. The object of this study was to determine if tobacco smoking in humans produces localized or widespread neocortical dominant alpha electroencephalographic (EEG) frequency increases consistent with nicotine stimulation of the brainstem activating system in animals. Twenty-two male volunteer non-deprived tobacco smokers were studied. They were asked not to smoke for at least 1 hr before the experiment in mid-morning as part of their usual smoking schedule. In the laboratory, they sham smoked and then smoked their favorite tobacco cigarette. Two experimental sessions (#1 and #2) were conducted, separated by a one to two month interval. In both sessions, there were minor statistically significant increases in the dominant alpha frequencies after sham smoking. In both sessions, after the subjects smoked a favorite tobacco cigarette there was a significant generalized increase in dominant alpha EEG frequencies in most scalp recording sites. This study demonstrates that tobacco smoking produces widespread bilateral neocortical increases in dominant alpha EEG frequencies consistent with the stimulant effects of nicotine on the brainstem reticular activating system.

Domino, Edward F.; Ni, Lisong; Thompson, Michael; Zhang, Huilea; Shikata, Hiroki; Fukai, Hiromi; Sakaki, Takeshi; Ohya, Ippei

2009-01-01

387

EEG diagnostic and predictive value on HIV infection in childhood.  

PubMed

This prospective study evaluated the electroencephalographic (EEG) diagnostic and prognostic value in childhood HIV infection. It was carried out on 125 subjects and included all Piemonte's seropositive children. The EEG was repeated every three months during the first 15 months of life, and then, at least, annually in the P1 and P2 group. Data of group P2 was compared blindly to that of the seroconverted control group of the same age and risk. EEG results were normal in P0, P1 and control patients. In group P2, EEG was abnormal in 35.5% of subjects, of these 54.6% developed an encephalopathy with a delay of 2.5 months to 2 years 11 months. EEG is therefore useful to evaluate early CNS damage and to identify onset features and evolution of encephalopathy in P2 patients. PMID:7854257

Vigliano, P; Rigardetto, R; Capizzi, G; Arfelli, P; Barbicinti, I; Boffi, P; Bonassi, E; Cavallo, P; Crosa, P; Gandione, M

1994-11-01

388

Using Bayesian Model Selection to Characterize Neonatal Eeg Recordings  

NASA Astrophysics Data System (ADS)

The brains of premature infants must undergo significant maturation outside of the womb and are thus particularly susceptible to injury. Electroencephalographic (EEG) recordings are an important diagnostic tool in determining if a newborn's brain is functioning normally or if injury has occurred. However, interpreting the recordings is difficult and requires the skills of a trained electroencephelographer. Because these EEG specialists are rare, an automated interpretation of newborn EEG recordings would increase access to an important diagnostic tool for physicians. To automate this procedure, we employ Bayesian probability theory to compute the posterior probability for the EEG features of interest and use the results in a program designed to mimic EEG specialists. Specifically, we will be identifying waveforms of varying frequency and amplitude, as well as periods of flat recordings where brain activity is minimal.

Mitchell, Timothy J.

2009-12-01

389

Brain stem reticular formation and activation of the EEG.  

PubMed

1. Stimulation of the reticular formation of the brain stem evokes changes in the EEG, consisting of abolition of synchronized discharge and introduction of low voltage fast activity in its place, which are not mediated by any of the known ascending or descending paths that traverse the brain stem. The alteration is a generalized one but is most pronounced in the ipsilateral hemisphere and, sometimes, in its anterior part. 2. This response can elicited by stimulating the medical bulbar reticular formation, pontile and midbrain tegmentum, and dorsal hypothalamus and subthalamus. The bulbar effect is due to ascending impulses relayed through these more cephalic structures. The excitable substrate possesses a low threshold and responds best to high frequencies of stimulation. 3. Some background synchrony of electrocortical activity is requisite for manifestation of the response. In the "encephale isolé", reticular stimulation has no additional effect upon the fully activated EEG. With synchrony, in spontaneous drowsiness or light chloralosane anesthesia, the effect of reticular stimulation is strikingly like Berger's alpha wave blockade, or any arousal reaction. In full chloralosane anesthesia, high voltage slow waves are blocked but no increase in lower amplitude, fast activity occurs. With barbiturate anesthesia, the reticular response is difficult to elicit or is abolished. 4. In the chloralosane preparation, the secondary cortical response evoked by a sensory volley is generally unaffected by reticular stimulation. Consequent sensory after-discharge is abolished, however, as is pyramidal tract discharge and jerky movements referable to it. Outside the sensory receiving area, secondary responses themselves may be reduced or prevented. 5. The convulsive spikes produced by local strychnine and those of a fit following supramaximal cortical excitation, are not decreased by stimulating the reticular formation. 6. The cortical recruiting response induced by low frequency stimulation of the diffuse thalamic projection system is reduced or abolished by reticular stimulation. 7. There is some indication that the cortical effect of reticular stimulation may be mediated by this diffuse thalamic projection system, for synchronized activity within it is similarly prevented by reticular excitation, and direct high frequency stimulation of this system, within the thalamus, reproduces the reticular response. It is possible, however, that other mechanisms may be involved in its mediation. 8. The reticular response and the arousal reaction to natural stimuli have been compared in the "encéphale isolé", in which EEG synchrony was present during spontaneous relaxation or was produced by recruiting mechanisms, and the two appear identical. 9. The possibility that the cortical arousal reaction to natural stimuli is mediated by collaterals of afferent pathways to the brain stem reticular formation, and thence through the ascending reticular activating system, rather than by intra-cortical spread following the arrival of afferent impulses at the sensory receiving areas of the cortex, is under investigation. 10. The possibility is considered that a background of maintained activity within this ascending brain stem activating system may account for wakefulness, while reduction of its activity either naturally, by barbiturates, or by experimental injury and disease, may respectively precipitate normal sleep, contribute to anesthesia or produce pathological somnolence. PMID:18421835

Moruzzi, G; Magoun, H W

1949-11-01

390

[Structural and functional peculiarity of brain activity to performance and imaginary motor tasks in healthy persons (EEG and fMRI study)].  

PubMed

Bioelectrical (EEG) and hemodynamic (fMRI-response) cerebral reactions to performance and imaginary motor tasks by right or left hand were analyzed in 15 right-handed healthy persons (21-39 years old). During actual movement the main fMRI-response was registered in the area of central gyrus of the hemisphere contralateral to the working hand. Areas of activation were also revealed in the supplemental motor area and the ipsilateral hemisphere of the cerebellum. EEG data showed coherence increase in high frequency alpha- and beta-bands in the activated hemisphere. In imaginary motor tasks the intensity and topography of fMRI-response became the more variable; response was decreased in the motor area and in cerebellum, they increased in the subcortical structures and in the parietal association zones. EEG changes were very variable in this situation also; it was observe an increase of EEG coherence in the right hemisphere for higher frequency of alpha and beta spectral bands. Changes of power spectrum parameters were similar to performance and imaginary motor tasks. Spectrum power and middle frequency of beta band were increased. Topographically these changes did not correspond to activated hemisphere and it was more in the left hemisphere. These changes were reflected nonspecific component of reaction. PMID:24450163

Boldyreva, G N; Sharova, E V; Zhavoronkova, L A; Cheliapina, M V; Dubrovskaia, L P; Simonova, O A; Fadeeva, L M; Pronin, I N; Kornienko, V N

2013-01-01

391

Differences in resting EEG related to ability.  

PubMed

The aim of the present study was to investigate the relationship between different EEG measures (mean power, mean frequency, approximated entropy and coherence), and ability (creativity and intelligence). For that purpose the EEG of 115 student-teachers (Intelligence: M= 115.17; SD = 12.78; IQ(min)= 82; IQ(max)= 136; Creativity - standardized scores: M = 55.97; SD = 10.67; C(min)= 38; C(max)= 84) was recorded while they were resting with eyes open and closed. The study showed only weak correlations between measures based on the level of activity in different areas (mean power, mean frequency and approximated entropy) and creativity. The correlations with IQ scores were even less pronounced. On the other hand, coherence measures showed a much more intense relationship both with creativity as well as with intelligence. In the eyes-open state these differences were mainly distributed over the right hemisphere. The results are discussed in the light of different theories relating brain functioning and ability. PMID:10791685

Jausovec, N; Jausovec, K

2000-01-01

392

Spatiotemporal Analysis of Multichannel EEG: CARTOOL  

PubMed Central

This paper describes methods to analyze the brain's electric fields recorded with multichannel Electroencephalogram (EEG) and demonstrates their implementation in the software CARTOOL. It focuses on the analysis of the spatial properties of these fields and on quantitative assessment of changes of field topographies across time, experimental conditions, or populations. Topographic analyses are advantageous because they are reference independents and thus render statistically unambiguous results. Neurophysiologically, differences in topography directly indicate changes in the configuration of the active neuronal sources in the brain. We describe global measures of field strength and field similarities, temporal segmentation based on topographic variations, topographic analysis in the frequency domain, topographic statistical analysis, and source imaging based on distributed inverse solutions. All analysis methods are implemented in a freely available academic software package called CARTOOL. Besides providing these analysis tools, CARTOOL is particularly designed to visualize the data and the analysis results using 3-dimensional display routines that allow rapid manipulation and animation of 3D images. CARTOOL therefore is a helpful tool for researchers as well as for clinicians to interpret multichannel EEG and evoked potentials in a global, comprehensive, and unambiguous way.

Brunet, Denis; Murray, Micah M.; Michel, Christoph M.

2011-01-01