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Sample records for eeg alpha phenotypes

  1. Magnetic Resonance Therapy Improves Clinical Phenotype and EEG Alpha Power in Posttraumatic Stress Disorder

    PubMed Central

    Taghva, Alexander; Silvetz, Robert; Ring, Alex; Kim, Keun-young A.; Murphy, Kevin T.; Liu, Charles Y.; Jin, Yi

    2015-01-01

    Background: Posttraumatic stress disorder (PTSD) is a disabling and prevalent psychiatric disorder with limited effective treatment options. In addition to the clinical features of the disease, pathologic changes in the electroencephalogram (EEG), including decreased alpha power, have been reported. Objectives: To determine if magnetic brain stimulation can induce normalization of EEG abnormalities and improve clinical symptoms in PTSD in a preliminary, open-label evaluation. Materials and Methods: We reviewed prospectively-collected data on 21 veterans that were consecutively-treated for PTSD. Magnetic resonance therapy (MRT) was administered for two weeks at treatment frequencies based on frequency-domain analysis of each patient’s dominant alpha-band EEG frequencies and resting heart rate. Patients were evaluated on the PTSD checklist (PCL-M) and pre- and post-treatment EEGs before and after MRT. Results: Of the 21 patients who initiated therapy, 16 completed treatment. Clinical improvements on the PCL-M were seen in these 16 patients, with an average pre-treatment score of 54.9 and post-treatment score of 31.8 (P < 0.001). In addition, relative global EEG alpha-band (8 - 13 Hz) power increased from 32.0 to 38.5 percent (P = 0.013), and EEG delta-band (1 - 4 Hz) power decreased from 32.3 percent to 26.8 percent (P = 0.028). Conclusions: These open-label data show trends toward normalization of EEG and concomitant clinical improvement using magnetic stimulation for PTSD. PMID:26839865

  2. Low voltage alpha EEG phenotype is associated with reduced amplitudes of alpha event-related oscillations, increased cortical phase synchrony, and a low level of response to alcohol.

    PubMed

    Ehlers, Cindy L; Wills, Derek N; Phillips, Evelyn; Havstad, James

    2015-10-01

    Low voltage EEG (LVEEG) is a heritable phenotype that differs depending on ancestral heritage, yet its impact on brain networks and cognition remain relatively unexplored. In this study we assessed energy and task related phase locking of event-related oscillation (EROs), behavioral responses, measures of IQ and personality, and expected responses to alcohol in a large sample of individuals with LVEEG compared to those with higher voltage variants. Participants (n=762) were recruited from a Native American community and completed a diagnostic interview, the Quick Test, the Subjective High Assessment Scale Expectation Version (SHAS-E) and the Maudsley Personality Inventory. Clinical and spectral analyzed EEGs were collected for determination of the presence of a LVEEG variant. EROs were generated using a facial expression recognition task. Participants with LVEEG (n=451) were significantly more likely to be older, married and have higher degrees of Native American heritage but did not differ in gender, income or education. Individuals with LVEEG were also found to have decreased energy in their alpha EROs, increased phase locking between stimulus trials, and increased phase-locking between cortical brain areas. No significant differences in the cognitive tests, personality variables or alcohol dependence or anxiety diagnoses were found, however, individuals with LVEEG did report a larger number of drinks ever consumed in a 24-h period and a less intense expected response to alcohol. These data suggest that alpha power in the resting EEG is highly associated with energy and cortical connectivity measures generated by event-related stimuli, as well as potentially increased risk for alcohol use. PMID:26151497

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

    PubMed Central

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

    2009-01-01

    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. PMID:19185213

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

    PubMed

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

    2009-02-01

    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. PMID:19185213

  5. EEG alpha power and creative ideation☆

    PubMed Central

    Fink, Andreas; Benedek, Mathias

    2014-01-01

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

  6. EEG alpha power and creative ideation.

    PubMed

    Fink, Andreas; Benedek, Mathias

    2014-07-01

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

  7. Relationship of genetically transmitted alpha EEG traits to anxiety disorders and alcoholism

    SciTech Connect

    Enoch, M.A.; Rohrbaugh, W.; Harris, C.R.

    1995-10-09

    We tested the hypothesis that a heritable EEG trait, the low voltage alpha (LV), is associated with psychiatric disorders. Modest to moderate evidence for genetic linkage of both panic disorder and the low voltage alpha trait to the same region of chromosome 20q has recently been reported, raising the issue of whether there is a phenotypic correlation between these traits. A total of 124 subjects including 50 unrelated index subjects and 74 relatives were studied. Alpha EEG power was measured and EEG phenotypes were impressionistically classified. Subjects were psychiatrically interviewed using the SADS-L and blind-rated by RDC criteria. Alcoholics were four times more likely to be LV (including so-called borderline low voltage alpha) than were nonalcoholic, nonanxious subjects. Alcoholics with anxiety disorder are 10 times more likely to be LV. However, alcoholics without anxiety disorder were similar to nonalcoholics in alpha power. An anxiety disorder (panic disorder, phobia, or generalized anxiety) was found in 14/17 LV subjects as compared to 34/101 of the rest of the sample (P < 0.01). Support for these observations was found in the unrelated index subjects in whom no traits would be shared by familial clustering. Lower alpha power in anxiety disorders was not state-dependent, as indicated by the Spielberger Anxiety Scale. Familial covariance of alpha power was 0.25 (P < 0.01). These findings indicate there may be a shared factor underlying the transmissible low voltage alpha EEG variant and vulnerability to anxiety disorders with associated alcoholism. This factor is apparently not rare, because LV was found in approximately 10% of unrelated index subjects and 5% of subjects free of alcoholism and anxiety disorders. 43 refs., 1 fig., 3 tabs.

  8. Theta and alpha EEG frequency interplay in subjects with mild cognitive impairment: evidence from EEG, MRI, and SPECT brain modifications

    PubMed Central

    Moretti, Davide V.

    2015-01-01

    Background: Temporo-parietal and medial temporal cortex atrophy are associated with mild cognitive impairment (MCI) due to Alzheimer disease (AD) as well as the reduction of regional cerebral blood perfusion in hippocampus. Moreover, the increase of EEG alpha3/alpha2 power ratio has been associated with MCI due to AD and with an increase in theta frequency power in a group of subjects with impaired cerebral perfusion in hippocampus. Methods: Seventy four adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording and high resolution 3D magnetic resonance imaging (MRI). Among the patients, a subset of 27 subjects underwent also perfusion single-photon emission computed tomography and hippocampal atrophy evaluation. 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 alpha3/alpha2 power ratio and difference of cortical thickness among the groups estimated. Results: Higher alpha3/alpha2 power ratio group had wider cortical thinning than other groups, mapped to the Supramarginal and Precuneus bilaterally. Subjects with higher alpha3/alpha2 frequency power ratio showed a constant trend to a lower perfusion than lower alpha3/alpha2 group. Moreover, this group correlates with both a bigger hippocampal atrophy and an increase of theta frequency power. Conclusion: Higher EEG alpha3/alpha2 power ratio was associated with temporo-parietal cortical thinning, hippocampal atrophy and reduction of regional cerebral perfusion in medial temporal cortex. In this group an increase of theta frequency power was detected inMCI subjects. The combination of higher EEG alpha3/alpha2 power ratio, cortical thickness measure and regional cerebral perfusion reveals a complex interplay between EEG cerebral rhythms, structural and functional brain modifications. PMID:25926789

  9. Endotoxin enhances EEG alpha and beta power in human sleep.

    PubMed

    Trachsel, L; Schreiber, W; Holsboer, F; Pollmächer, T

    1994-03-01

    Endotoxin, a lipopolysaccharide (0.4 or 0.8 ng/kg body weight), was injected at 1900 hours in 17 healthy men in a single-blind, placebo-controlled experiment. The administration was followed by a 4-hour period of quiet wakefulness in bed (light intensity < 200 lux). Unlimited sleep was allowed after 2300 hours (lights off) until the next morning. The electroencephalogram (EEG), electromyogram, electrooculogram, electrocardiogram and rectal temperature were recorded throughout the experimental session. Standard sleep stages were assessed, and the EEG was submitted to a state-specific, serial spectral analysis. Endotoxin administration induced a rise of body temperature and heart rate, which started approximately 2 hours after the injection and persisted through most of the sleep period. Sleep latency remained unchanged, whereas rapid eye movement (REM) sleep latency increased from 60.3 to 89.0 minutes (paired t test; p = 0.06) compared to control values. Stage 2 sleep was elevated from 45.5 to 49.0% of time in bed (p < 0.05), and total nonrapid eye movement (NREM) sleep from 64.2 to 69.1% (p < 0.05). No significant change could be observed in slow-wave sleep (SWS, stages 3 and 4). During the first 4 hours of the sleep period, NREM sleep EEG spectral power was distinctly and markedly increased between 8 and 12 Hz (alpha) and 15 and 20 Hz (beta) (p < 0.05), whereas at the same time EEG power between 1 and 8 Hz (delta, theta) was not significantly changed. We conclude that in humans the primary host response induced by endotoxin initially suppresses REM sleep and increases stage 2 NREM sleep, but does not affect SWS. No clear modification of sleep EEG delta activity could be observed after endotoxin injection, despite marked endocrinological and physiological changes such as the elevation of body temperature. Numerous factors related to the human primary host response may be responsible for the EEG intensification of the alpha and beta range. PMID:8036367

  10. Intra-cortical propagation of EEG alpha oscillations.

    PubMed

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

    2014-12-01

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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

    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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

    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…

  13. Alpha-band EEG activity in perceptual learning

    PubMed Central

    Bays, Brett C.; Visscher, Kristina M.; Le Dantec, Christophe C.; Seitz, Aaron R.

    2015-01-01

    In studies of perceptual learning (PL), subjects are typically highly trained across many sessions to achieve perceptual benefits on the stimuli in those tasks. There is currently significant debate regarding what sources of brain plasticity underlie these PL-based learning improvements. Here we investigate the hypothesis that PL, among other mechanisms, leads to task automaticity, especially in the presence of the trained stimuli. To investigate this hypothesis, we trained participants for eight sessions to find an oriented target in a field of near-oriented distractors and examined alpha-band activity, which modulates with attention to visual stimuli, as a possible measure of automaticity. Alpha-band activity was acquired via electroencephalogram (EEG), before and after training, as participants performed the task with trained and untrained stimuli. Results show that participants underwent significant learning in this task (as assessed by threshold, accuracy, and reaction time improvements) and that alpha power increased during the pre-stimulus period and then underwent greater desynchronization at the time of stimulus presentation following training. However, these changes in alpha-band activity were not specific to the trained stimuli, with similar patterns of posttraining alpha power for trained and untrained stimuli. These data are consistent with the view that participants were more efficient at focusing resources at the time of stimulus presentation and are consistent with a greater automaticity of task performance. These findings have implications for PL, as transfer effects from trained to untrained stimuli may partially depend on differential effort of the individual at the time of stimulus processing. PMID:26370167

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

    PubMed

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

    2010-01-15

    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 (h(2)) 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. PMID:19748744

  15. Spatial Organization of Alpha Range Potentials on EEG and Logical Thinking Effectiveness.

    PubMed

    Dzhebrailova, T D; Korobeinikova, I I; Dudnik, E N; Karatygin, N A

    2015-06-01

    We studied spatial organization of EEG alpha range potentials in volunteers with different results of tasks requiring logical thinking. The examinees with higher cognitive test performance have more labile coherent associations of EEG alpha range potentials, which manifested in changes in the level and structure of these associations at different stages of the test. In individuals with poor results, the number of significant coherent associations and their structure do not change during the problem solving process. PMID:26095515

  16. Neuronal generators of posterior EEG alpha reflect individual differences in prioritizing personal spirituality

    PubMed Central

    Tenke, C. E.; Kayser, J.; Miller, L.; Warner, V.; Wickramaratne, P.; Weissman, M. M.; Bruder, G. E.

    2013-01-01

    Prominent posterior EEG alpha is associated with depression and clinical response to antidepressants. Given that religious belief was protective against depression in a longitudinal study of familial risk, we hypothesized that individuals who differed by strength of spiritual beliefs might also differ in EEG alpha. Clinical evaluations and self-reports of the importance of religion or spirituality (R/S) were obtained from 52 participants, and again at 10-y followup when EEG was measured. EEG alpha was quantified using frequency PCA of current source densities (CSD-fPCA). Participants who rated R/S as highly important at initial assessment showed greater alpha compared to those who did not. Those who rated R/S important in both sessions showed greater alpha than those who changed their ratings. EEG differences were particularly well-defined for participants with lifetime depression. Findings extend the view of alpha as a marker for affective processes, suggesting an association with the ontogenesis of spirituality. PMID:23998996

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

    PubMed Central

    2013-01-01

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

  18. EEG alpha frequency correlates of burnout and depression: The role of gender.

    PubMed

    Tement, Sara; Pahor, Anja; Jauovec, Norbert

    2016-02-01

    EEG alpha frequency band biomarkers of depression are widely explored. Due to their trait-like features, they may help distinguish between depressive and burnout symptomatology, which is often referred to as "work-related depression". The present correlational study strived to examine whether individual alpha frequency (IAF), power, and coherence in the alpha band can provide evidence for establishing burnout as a separate diagnostic entity. Resting EEG (eyes closed) was recorded in 117 individuals (42 males). In addition, the participants filled-out questionnaires of burnout and depression. Regression analyses highlighted the differential value of IAF and power in predicting burnout and depression. IAF was significantly related to depressive symptomatology, whereas power was linked mostly to burnout. Moreover, seven out of twelve interactions between EEG indicators and gender were significant. Connectivity patterns were significant for depression displaying gender-related differences. The results offer tentative support for establishing burnout as a separate clinical syndrome. PMID:26631352

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

    PubMed

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

    2011-12-01

    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

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

    PubMed Central

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

    2014-01-01

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

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

    ERIC Educational Resources Information Center

    Lally, Marianne B.

    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…

  2. EEG alpha activity is associated with individual differences in post-break improvement.

    PubMed

    Lim, Julian; Quevenco, Frances-Catherine; Kwok, Kenneth

    2013-08-01

    Continuous EEG activity has been used increasingly as a marker of mental and cognitive states, with previous work linking particular neural patterns to conditions of arousal or fatigue. This approach is more commonly used to assess task-related, as opposed to resting-state activity. In this study, we recorded the EEG of 31 healthy individuals as they performed two sessions of a 65-minute auditory oddball task, one with, and one without a 5-minute break opportunity. Over the course of the task, reaction times, as well as EEG power in theta and lower alpha bands increased in both conditions, but did not differ significantly between conditions. Over the period of the break, delta and theta EEG activity decreased significantly in comparison with activity in the equivalent period in the no-break condition. Individual differences in response to the break were observed, with approximately half the subjects showing an improvement, and half showing a decline. These individual differences were correlated both with decreases in theta activity, as well as resting upper alpha power during the period of the break. Our results suggest that tonic EEG activity during resting periods is meaningfully related to behavioral change between individuals based on physiological or psychological factors that remain to be explored. PMID:23523810

  3. EEG

    MedlinePlus

    Abnormal results on an EEG test may be due to: Abnormal bleeding (hemorrhage) An abnormal structure in the brain (such as a brain tumor ) Tissue death due to a blockage in blood flow (cerebral infarction) Drug or ...

  4. EEG alpha synchronization is related to top-down processing in convergent and divergent thinking

    PubMed Central

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

    2011-01-01

    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 demands and to specific cognitive process involved in creative thinking. To this end, EEG was measured during a convergent and a divergent thinking task (i.e., creativity-related task) which once were processed involving low and once involving high internal processing demands. High internal processing demands were established by masking the stimulus (after encoding) and thus preventing further bottom-up processing. Frontal alpha synchronization was observed during convergent and divergent thinking only under exclusive top-down control (high internal processing demands), but not when bottom-up processing was allowed (low internal processing demands). We conclude that frontal alpha synchronization is related to top-down control rather than to specific creativity-related cognitive processes. Frontal alpha synchronization, which has been observed in a variety of different creativity tasks, thus may not reflect a brain state that is specific for creative cognition but can probably be attributed to high internal processing demands which are typically involved in creative thinking. PMID:21925520

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-01-01

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

  7. Topographic deficits in alpha-range resting EEG activity and steady state visual evoked responses in schizophrenia.

    PubMed

    Goldstein, Michael R; Peterson, Michael J; Sanguinetti, Joseph L; Tononi, Giulio; Ferrarelli, Fabio

    2015-10-01

    Deficits in both resting alpha-range (8-12Hz) electroencephalogram (EEG) activity and steady state evoked potential (SSVEP) responses have been reported in schizophrenia. However, the topographic specificity of these effects, the relationship between resting EEG and SSVEP, as well as the impact of antipsychotic medication on these effects, have not been clearly delineated. The present study sought to address these questions with 256 channel high-density EEG recordings in a group of 13 schizophrenia patients, 13 healthy controls, and 10 non-schizophrenia patients with psychiatric diagnoses currently taking antipsychotic medication. At rest, the schizophrenia group demonstrated decreased alpha EEG power in frontal and occipital areas relative to healthy controls. With SSVEP stimulation centered in the alpha band (10Hz), but not with stimulation above (15Hz) or below (7Hz) this range, the occipital deficit in alpha power was partially reverted. However, the frontal deficit persisted and contributed to a significantly reduced topographic relationship between occipital and frontal alpha activity for resting EEG and 10Hz SSVEP alpha power in schizophrenia patients. No significant differences were observed between healthy and medicated controls or between medicated controls and schizophrenia. These findings suggest a potential intrinsic deficit in frontal eyes-closed EEG alpha oscillations in schizophrenia, whereby potent visual stimulation centered in that frequency range results in an increase in the occipital alpha power of these patients, which however does not extend to frontal regions. Future research to evaluate the cortical and subcortical mechanisms of these effects is warranted. PMID:26159669

  8. Interval analysis of interictal EEG: pathology of the alpha rhythm in focal epilepsy

    NASA Astrophysics Data System (ADS)

    Pyrzowski, Jan; Siemiński, Mariusz; Sarnowska, Anna; Jedrzejczak, Joanna; Nyka, Walenty M.

    2015-11-01

    The contemporary use of interictal scalp electroencephalography (EEG) in the context of focal epilepsy workup relies on the visual identification of interictal epileptiform discharges. The high-specificity performance of this marker comes, however, at a cost of only moderate sensitivity. Zero-crossing interval analysis is an alternative to Fourier analysis for the assessment of the rhythmic component of EEG signals. We applied this method to standard EEG recordings of 78 patients divided into 4 subgroups: temporal lobe epilepsy (TLE), frontal lobe epilepsy (FLE), psychogenic nonepileptic seizures (PNES) and nonepileptic patients with headache. Interval-analysis based markers were capable of effectively discriminating patients with epilepsy from those in control subgroups (AUC~0.8) with diagnostic sensitivity potentially exceeding that of visual analysis. The identified putative epilepsy-specific markers were sensitive to the properties of the alpha rhythm and displayed weak or non-significant dependences on the number of antiepileptic drugs (AEDs) taken by the patients. Significant AED-related effects were concentrated in the theta interval range and an associated marker allowed for identification of patients on AED polytherapy (AUC~0.9). Interval analysis may thus, in perspective, increase the diagnostic yield of interictal scalp EEG. Our findings point to the possible existence of alpha rhythm abnormalities in patients with epilepsy.

  9. Interval analysis of interictal EEG: pathology of the alpha rhythm in focal epilepsy

    PubMed Central

    Pyrzowski, Jan; Siemiński, Mariusz; Sarnowska, Anna; Jedrzejczak, Joanna; Nyka, Walenty M.

    2015-01-01

    The contemporary use of interictal scalp electroencephalography (EEG) in the context of focal epilepsy workup relies on the visual identification of interictal epileptiform discharges. The high-specificity performance of this marker comes, however, at a cost of only moderate sensitivity. Zero-crossing interval analysis is an alternative to Fourier analysis for the assessment of the rhythmic component of EEG signals. We applied this method to standard EEG recordings of 78 patients divided into 4 subgroups: temporal lobe epilepsy (TLE), frontal lobe epilepsy (FLE), psychogenic nonepileptic seizures (PNES) and nonepileptic patients with headache. Interval-analysis based markers were capable of effectively discriminating patients with epilepsy from those in control subgroups (AUC~0.8) with diagnostic sensitivity potentially exceeding that of visual analysis. The identified putative epilepsy-specific markers were sensitive to the properties of the alpha rhythm and displayed weak or non-significant dependences on the number of antiepileptic drugs (AEDs) taken by the patients. Significant AED-related effects were concentrated in the theta interval range and an associated marker allowed for identification of patients on AED polytherapy (AUC~0.9). Interval analysis may thus, in perspective, increase the diagnostic yield of interictal scalp EEG. Our findings point to the possible existence of alpha rhythm abnormalities in patients with epilepsy. PMID:26553287

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

    PubMed Central

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

    2013-01-01

    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. PMID:23824708

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

    PubMed

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

    2013-01-01

    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. PMID:23824708

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

    PubMed

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

    2014-12-01

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

  13. EEG Alpha and Beta Activity in Normal and Deaf Subjects.

    ERIC Educational Resources Information Center

    Waldron, Manjula; And Others

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

  14. EEG Alpha Rhythm Frequency and Intelligence in Normal Adults.

    ERIC Educational Resources Information Center

    Anokhin, Andrey; Vogel, Friedrich

    1996-01-01

    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)

  15. EEG alpha blocking correlated with perception of inner light during zen meditation.

    PubMed

    Lo, Pei-Chen; Huang, Ming-Liang; Chang, Kang-Ming

    2003-01-01

    According to the experimental results and practitioners' subjective experience, we report some hypotheses that may account for meditative phenomena during the practice of Zen-Buddhism. Orthodox Zen-Buddhist practitioners, aiming to prove the most original true-self, discover and uncover the inner energy or light on the way towards their goal. Perception of the inner light can be comprehended as resonance. Uncovering the inner energy optimizes physiological and mental health. In the meditation experiment, a significant correlation was observed between perception of the inner light and electroencephalographic (EEG) alpha blockage. We further examined this phenomenon by recording the EEG from subjects during a blessing that the subjects did not know being given. During the blessing period, significant alpha blocking was observed in experimental subjects who had been practicing meditation for years in preparation for being in resonance with the inner light. This report provides a new insight into the debate that meditation benefits our health. PMID:14587885

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

    PubMed

    Stinson, Bruce; Arthur, David

    2013-08-01

    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

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

    PubMed Central

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

    2014-01-01

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

  18. The validity of individual frontal alpha asymmetry EEG neurofeedback.

    PubMed

    Quaedflieg, C W E M; Smulders, F T Y; Meyer, T; Peeters, F; Merckelbach, H; Smeets, T

    2016-01-01

    Frontal asymmetry in alpha oscillations is assumed to be associated with psychopathology and individual differences in emotional responding. Brain-activity-based feedback is a promising tool for the modulation of cortical activity. Here, we validated a neurofeedback protocol designed to change relative frontal asymmetry based on individual alpha peak frequencies, including real-time average referencing and eye-correction. Participants (N = 60) were randomly assigned to a right, left or placebo neurofeedback group. Results show a difference in trainability between groups, with a linear change in frontal alpha asymmetry over time for the right neurofeedback group during rest. Moreover, the asymmetry changes in the right group were frequency and location specific, even though trainability did not persist at 1 week and 1 month follow-ups. On the behavioral level, subjective stress on the second test day was reduced in the left and placebo neurofeedback groups, but not in the right neurofeedback group. We found individual differences in trainability that were dependent on training group, with participants in the right neurofeedback group being more likely to change their frontal asymmetry in the desired direction. Individual differences in trainability were also reflected in the ability to change frontal asymmetry during the feedback. PMID:26163671

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

    PubMed Central

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

    2015-01-01

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

  20. Posterior EEG alpha at rest and during task performance: Comparison of current source density and field potential measures.

    PubMed

    Tenke, Craig E; Kayser, Jürgen; Abraham, Karen; Alvarenga, Jorge E; Bruder, Gerard E

    2015-09-01

    Resting and task-related EEG alpha are used in studies of cognition and psychopathology. Although Laplacian methods have been applied, apprehensions about loss of global activity dissuade researchers from greater use except as a supplement to reference-dependent measures. The unfortunate result has been continued reliance on reference strategies that differ across labs, and a systemic preference for a montage-dependent average reference over true reference-free measures. We addressed these concerns by comparing resting- and task-related EEG alpha using three EEG transformations: nose- (NR) and average-referenced (AR) EEG, and the corresponding CSD. Amplitude spectra of resting and prestimulus task-related EEG (novelty oddball) and event-related spectral perturbations were scaled to equate each transformation. Alpha measures quantified for 8-12 Hz bands were: 1) net amplitude (eyes-closed minus eyes-open) and 2) overall amplitude (eyes-closed plus eyes-open); 3) task amplitude (prestimulus baseline) and 4) task event-related desynchronization (ERD). Mean topographies unambiguously represented posterior alpha for overall, net and task, as well as poststimulus alpha ERD. Topographies were similar for the three transformations, but differed in dispersion, CSD being sharpest and NR most broadly distributed. Transformations also differed in scale, AR showing less attenuation or spurious secondary maxima at anterior sites, consistent with simulations of distributed posterior generators. Posterior task alpha and alpha ERD were positively correlated with overall alpha, but not with net alpha. CSD topographies consistently and appropriately represented posterior EEG alpha for all measures. PMID:26026372

  1. Visual dream content, graphical representation and EEG alpha activity in congenitally blind subjects.

    PubMed

    Bértolo, Helder; Paiva, Teresa; Pessoa, Lara; Mestre, Tiago; Marques, Raquel; Santos, Rosa

    2003-02-01

    It is currently claimed that congenitally blind do not have visual imagery and are therefore unable to present visual contents in their dreams. The aim of our study was to quantitatively evaluate the existence of visual imagery in born-blind dreams and to correlate it with objective measures, such as sleep EEG frequency components, namely with alpha attenuation (regarded as an indicator of visual activity), and graphical analysis of dream pictorial representations. The investigation was carried out via simultaneous recordings of dream reports and polysomnography, during nocturnal sleep at volunteers' homes; scheduled regular awakenings during the night provided the data for dream and EEG analysis. In the morning, subjects were asked to make a drawing of their dream images. Congenitally blind (n=10) were comparable to normal sighted subjects (n=9): the two groups presented equivalent visual activity indices, and no differences in the analysis of graphical representation of dreaming imagery. However, blind subjects presented a lower rate of dream recall than sighted (27% versus 42%). Both groups had significant negative correlation between Visual Activity Index (VAI) and alpha power in the central and occipital O2 derivations (blind: C4: r=-0.615, P<0.005; O2: r=-0.608, P<0.006; sighted: C4: r=-0.633, P<0.01; O2: r=-0.506, P<0.05). This correlation was weaker for the blind in O1 (r=-0.573, P<0.05) and non-existent for the sighted. Blind individuals have significantly lower alpha activity in the central derivation. In conclusion, the congenitally blind have visual content in their dreams and are able to draw it and, as expected, their VAI is negatively correlated with EEG alpha power. PMID:12527101

  2. Brief Report: Reduced Temporal-Central EEG Alpha Coherence During Joint Attention Perception in Adolescents with Autism Spectrum Disorder.

    PubMed

    Jaime, Mark; McMahon, Camilla M; Davidson, Bridget C; Newell, Lisa C; Mundy, Peter C; Henderson, Heather A

    2016-04-01

    Although prior studies have demonstrated reduced resting state EEG coherence in adults with autism spectrum disorder (ASD), no studies have explored the nature of EEG coherence during joint attention. We examined the EEG coherence of the joint attention network in adolescents with and without ASD during congruent and incongruent joint attention perception and an eyes-open resting condition. Across conditions, adolescents with ASD showed reduced right hemisphere temporal-central alpha coherence compared to typically developing adolescents. Greater right temporal-central alpha coherence during joint attention was positively associated with social cognitive performance in typical development but not in ASD. These results suggest that, in addition to a resting state, EEG coherence during joint attention perception is reduced in ASD. PMID:26659813

  3. EEG alpha band synchrony predicts cognitive and motor performance in patients with ischemic stroke.

    PubMed

    Dubovik, Sviatlana; Ptak, Radek; Aboulafia, Tatiana; Magnin, Cécile; Gillabert, Nicole; Allet, Lara; Pignat, Jean-Michel; Schnider, Armin; Guggisberg, Adrian G

    2013-01-01

    Functional brain networks are known to be affected by focal brain lesions. However, the clinical relevance of these changes remains unclear. This study assesses resting-state functional connectivity (FC) with electroencephalography (EEG) and relates observed topography of FC to cognitive and motor deficits in patients three months after ischemic stroke. Twenty patients (mean age 61.3 years, range 37-80, 9 females) and nineteen age-matched healthy participants (mean age 66.7 years, range 36-88, 13 females) underwent a ten-minute EEG-resting state examination. The neural oscillations at each grey matter voxel were reconstructed using an adaptive spatial filter and imaginary component of coherence (IC) was calculated as an index of FC. Maps representing mean connectivity value at each voxel were correlated with the clinical data. Compared to healthy controls, alpha band IC of stroke patients was locally reduced in brain regions critical to observed behavioral deficits. A voxel-wise Pearson correlation of clinical performances with FC yielded maps of the neural structures implicated in motor, language, and executive function. This correlation was again specific to alpha band coherence. Ischemic lesions decrease the synchrony of alpha band oscillations between affected brain regions and the rest of the brain. This decrease is linearly related to cognitive and motor deficits observed in the patients. PMID:22713421

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

    SciTech Connect

    Devinsky, O.; Sato, S.; Conwit, R.A.; Schapiro, M.B. )

    1990-01-01

    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.

  5. Regarding the database for the Peniston alpha-theta EEG biofeedback protocol.

    PubMed

    Graap, K; Freides, D

    1998-12-01

    Five papers by Peniston and colleagues, which constitute the basic literature for alpha-theta EEG biofeedback treatment for alcoholism and posttraumatic stress disorder, are reviewed. As a result, we raise three questions: (a) Are the samples studied independent? (b) What was the clinical status of the participants prior to treatment? (c) What treatment did the participants actually receive? In seeking answers to these questions we aim to strengthen the database for neurofeedback with specific procedural information so that claims of efficacy can be tested and accepted or rejected on an objective basis. PMID:10457816

  6. Detecting Driver Mental Fatigue Based on EEG Alpha Power Changes during Simulated Driving

    PubMed Central

    GHARAGOZLOU, Faramarz; NASL SARAJI, Gebraeil; MAZLOUMI, Adel; NAHVI, Ali; MOTIE NASRABADI, Ali; RAHIMI FOROUSHANI, Abbas; ARAB KHERADMAND, Ali; ASHOURI, Mohammadreza; SAMAVATI, Mehdi

    2015-01-01

    Background: Driver fatigue is one of the major implications in transportation safety and accounted for up to 40% of road accidents. This study aimed to analyze the EEG alpha power changes in partially sleep-deprived drivers while performing a simulated driving task. Methods: Twelve healthy male car drivers participated in an overnight study. Continuous EEG and EOG records were taken during driving on a virtual reality simulator on a monotonous road. Simultaneously, video recordings from the driver face and behavior were performed in lateral and front views and rated by two trained observers. Moreover, the subjective self-assessment of fatigue was implemented in every 10-min interval during the driving using Fatigue Visual Analog Scale (F-VAS). Power spectrum density and fast Fourier transform (FFT) were used to determine the absolute and relative alpha powers in the initial and final 10 minutes of driving. Results: The findings showed a significant increase in the absolute alpha power (P = 0.006) as well as F-VAS scores during the final section of driving (P = 0.001). Meanwhile, video ratings were consistent with subjective self-assessment of fatigue. Conclusion: The increase in alpha power in the final section of driving indicates the decrease in the level of alertness and attention and the onset of fatigue, which was consistent with F-VAS and video ratings. The study suggested that variations in alpha power could be a good indicator for driver mental fatigue, but for using as a countermeasure device needed further investigations. PMID:26811821

  7. EEG Alpha and Gamma Modulators Mediate Motion Sickness-Related Spectral Responses.

    PubMed

    Chuang, Shang-Wen; Chuang, Chun-Hsiang; Yu, Yi-Hsin; King, Jung-Tai; Lin, Chin-Teng

    2016-03-01

    Motion sickness (MS) is a common experience of travelers. To provide insights into brain dynamics associated with MS, this study recruited 19 subjects to participate in an electroencephalogram (EEG) experiment in a virtual-reality driving environment. When riding on consecutive winding roads, subjects experienced postural instability and sensory conflict between visual and vestibular stimuli. Meanwhile, subjects rated their level of MS on a six-point scale. Independent component analysis (ICA) was used to separate the filtered EEG signals into maximally temporally independent components (ICs). Then, reduced logarithmic spectra of ICs of interest, using principal component analysis, were decomposed by ICA again to find spectrally fixed and temporally independent modulators (IMs). Results demonstrated that a higher degree of MS accompanied increased activation of alpha ([Formula: see text]) and gamma ([Formula: see text]) IMs across remote-independent brain processes, covering motor, parietal and occipital areas. This co-modulatory spectral change in alpha and gamma bands revealed the neurophysiological demand to regulate conflicts among multi-modal sensory systems during MS. PMID:26790485

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

    PubMed

    Kalauzi, Aleksandar; Vuckovic, Aleksandra; Bojić, Tijana

    2015-03-01

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

  9. Effects of Physical Exercise on Individual Resting State EEG Alpha Peak Frequency

    PubMed Central

    Gutmann, Boris; Mierau, Andreas; Hülsdünker, Thorben; Przyklenk, Axel; Strüder, Heiko Klaus

    2015-01-01

    Previous research has shown that both acute and chronic physical exercises can induce positive effects on brain function and this is associated with improvements in cognitive performance. However, the neurophysiological mechanisms underlying the beneficial effects of exercise on cognitive processing are not well understood. This study examined the effects of an acute bout of physical exercise as well as four weeks of exercise training on the individual resting state electroencephalographic (EEG) alpha peak frequency (iAPF), a neurophysiological marker of the individual's state of arousal and attention, in healthy young adults. The subjects completed a steady state exercise (SSE) protocol or an exhaustive exercise (EE) protocol, respectively, on two separate days. EEG activity was recorded for 2 min before exercise, immediately after exercise, and after 10 min of rest. All assessments were repeated following four weeks of exercise training to investigate whether an improvement in physical fitness modulates the resting state iAPF and/or the iAPF response to an acute bout of SSE and EE. The iAPF was significantly increased following EE (P = 0.012) but not following SSE. It is concluded that the iAPF is increased following intense exercise, indicating a higher level of arousal and preparedness for external input. PMID:25759762

  10. Effects of physical exercise on individual resting state EEG alpha peak frequency.

    PubMed

    Gutmann, Boris; Mierau, Andreas; Hlsdnker, Thorben; Hildebrand, Carolin; Przyklenk, Axel; Hollmann, Wildor; Strder, Heiko Klaus

    2015-01-01

    Previous research has shown that both acute and chronic physical exercises can induce positive effects on brain function and this is associated with improvements in cognitive performance. However, the neurophysiological mechanisms underlying the beneficial effects of exercise on cognitive processing are not well understood. This study examined the effects of an acute bout of physical exercise as well as four weeks of exercise training on the individual resting state electroencephalographic (EEG) alpha peak frequency (iAPF), a neurophysiological marker of the individual's state of arousal and attention, in healthy young adults. The subjects completed a steady state exercise (SSE) protocol or an exhaustive exercise (EE) protocol, respectively, on two separate days. EEG activity was recorded for 2?min before exercise, immediately after exercise, and after 10?min of rest. All assessments were repeated following four weeks of exercise training to investigate whether an improvement in physical fitness modulates the resting state iAPF and/or the iAPF response to an acute bout of SSE and EE. The iAPF was significantly increased following EE (P = 0.012) but not following SSE. It is concluded that the iAPF is increased following intense exercise, indicating a higher level of arousal and preparedness for external input. PMID:25759762

  11. Modulation of Alpha Oscillations in the Human EEG with Facial Preference

    PubMed Central

    Kang, Jae-Hwan; Kim, Su Jin; Cho, Yang Seok; Kim, Sung-Phil

    2015-01-01

    Facial preference that results from the processing of facial information plays an important role in social interactions as well as the selection of a mate, friend, candidate, or favorite actor. However, it still remains elusive which brain regions are implicated in the neural mechanisms underlying facial preference, and how neural activities in these regions are modulated during the formation of facial preference. In the present study, we investigated the modulation of electroencephalography (EEG) oscillatory power with facial preference. For the reliable assessments of facial preference, we designed a series of passive viewing and active choice tasks. In the former task, twenty-four face stimuli were passively viewed by participants for multiple times in random order. In the latter task, the same stimuli were then evaluated by participants for their facial preference judgments. In both tasks, significant differences between the preferred and non-preferred faces groups were found in alpha band power (8–13 Hz) but not in other frequency bands. The preferred faces generated more decreases in alpha power. During the passive viewing task, significant differences in alpha power between the preferred and non-preferred face groups were observed at the left frontal regions in the early (0.15–0.4 s) period during the 1-s presentation. By contrast, during the active choice task when participants consecutively watched the first and second face for 1 s and then selected the preferred one, an alpha power difference was found for the late (0.65–0.8 s) period over the whole brain during the first face presentation and over the posterior regions during the second face presentation. These results demonstrate that the modulation of alpha activity by facial preference is a top-down process, which requires additional cognitive resources to facilitate information processing of the preferred faces that capture more visual attention than the non-preferred faces. PMID:26394328

  12. Childhood EEG frontal alpha power as a predictor of adolescent antisocial behavior: A twin heritability study

    PubMed Central

    Niv, Sharon; Ashrafulla, Syed; Tuvblad, Catherine; Joshi, Anand; Raine, Adrian; Leahy, Richard; Baker, Laura A.

    2015-01-01

    High EEG frontal alpha power (FAP) is thought to represent a state of low arousal in the brain, which has been related in past research to antisocial behavior (ASB). We investigated a longitudinal sample of 900 twins in two assessments in late childhood and mid-adolescence to verify whether relationships exist between FAP and both aggressive and nonaggressive ASB. ASB was measured by the Child Behavioral Checklist, and FAP was calculated using connectivity analysis methods that used principal components analysis to derive power of the most dominant frontal activation. Significant positive predictive relationships emerged in males between childhood FAP and adolescent aggressive ASB using multilevel mixed modeling. No concurrent relationships were found. Using bivariate biometric twin modeling analysis, the relationship between childhood FAP and adolescent aggressive ASB in males was found to be entirely due to genetic factors, which were correlated r = 0.22. PMID:25456277

  13. Childhood EEG frontal alpha power as a predictor of adolescent antisocial behavior: a twin heritability study.

    PubMed

    Niv, Sharon; Ashrafulla, Syed; Tuvblad, Catherine; Joshi, Anand; Raine, Adrian; Leahy, Richard; Baker, Laura A

    2015-02-01

    High EEG frontal alpha power (FAP) is thought to represent a state of low arousal in the brain, which has been related in past research to antisocial behavior (ASB). We investigated a longitudinal sample of 900 twins in two assessments in late childhood and mid-adolescence to verify whether relationships exist between FAP and both aggressive and nonaggressive ASB. ASB was measured by the Child Behavioral Checklist, and FAP was calculated using connectivity analysis methods that used principal components analysis to derive power of the most dominant frontal activation. Significant positive predictive relationships emerged in males between childhood FAP and adolescent aggressive ASB using multilevel mixed modeling. No concurrent relationships were found. Using bivariate biometric twin modeling analysis, the relationship between childhood FAP and adolescent aggressive ASB in males was found to be entirely due to genetic factors, which were correlated r=0.22. PMID:25456277

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  16. Increase of theta frequency is associated with reduction in regional cerebral blood flow only in subjects with mild cognitive impairment with higher upper alpha/low alpha EEG frequency power ratio

    PubMed Central

    Moretti, Davide V.; Prestia, Annapaola; Binetti, Giuliano; Zanetti, Orazio; Frisoni, Giovanni B.

    2013-01-01

    Background: Several biomarkers have been proposed for detecting Alzheimer's disease (AD) in its earliest stages, that is, in the predementia stage. In an attempt to find noninvasive biomarkers, researchers have investigated the feasibility of neuroimaging tools, such as MRI, SPECT as well as neurophysiological measurements using EEG. Moreover, the increase of EEG alpha3/alpha2 frequency power ratio has been associated with AD-converters subjects with mild cognitive impairment (MCI). Objective: To study the association of alpha3/alpha2 frequency power ratio with regional cerebral blood flow (rCBF) changes in subjects with MCI. Methods: Twenty-seven adult subjects with MCI underwent EEG recording and perfusion single-photon emission computed tomography (SPECT) evaluation. The alpha3/alpha2 frequency power ratio was computed for each subject. Two groups were obtained according to the median values of alpha3/alpha2, at a cut-off of 1.17. Correlation between brain perfusion and EEG markers were detected. Results: Subjects with higher alpha3/alpha2 frequency power ratio showed a constant trend to a lower perfusion than low alpha3/alpha2 group. The two groups were significantly different as about the hippocampal volume and correlation with the theta frequency activity. Conclusion: There is a complex interplay between cerebral blood flow, theta frequency activity, and hippocampal volume in MCI patients with prodromal Alzheimer's disease, characterized by higher EEG alpha3/alpha2 frequency power ratio. PMID:24367305

  17. Reactivity of hemodynamic responses and functional connectivity to different states of alpha synchrony: a concurrent EEG-fMRI study

    PubMed Central

    Wu, Lei; Eichele, Tom; Calhoun, Vince D.

    2011-01-01

    Concurrent EEG-fMRI studies have provided increasing details of the dynamics of intrinsic brain activity during the resting state. Here, we investigate a prominent effect in EEG during relaxed resting, i.e. the increase of the alpha power when the eyes are closed compared to when the eyes are open. This phenomenon is related to changes in thalamo-cortical and cortico-cortical synchronization. In order to investigate possible changes to EEG-fMRI coupling and fMRI functional connectivity during the two states we adopted a data-driven approach that fuses the multimodal data on the basis of parallel ICA decompositions of the fMRI data in the spatial domain and of the EEG data in the spectral domain. The power variation of a posterior alpha component was used as a reference function to deconvolve the hemodynamic responses from occipital, frontal, temporal, and subcortical fMRI components. Additionally, we computed the functional connectivity between these components. The results showed widespread alpha hemodynamic responses and high functional connectivity during eyes-closed (EC) rest, while eyes open (EO) resting abolished many of the hemodynamic responses and markedly decreased functional connectivity. These data suggest that generation of local hemodynamic responses is highly sensitive to state changes that do not involve changes of mental effort or awareness. They also indicate the localized power differences in posterior alpha between EO and EC in resting state data are accompanied by spatially widespread amplitude changes in hemodynamic responses and inter-regional functional connectivity, i.e. low frequency hemodynamic signals display an equivalent of alpha reactivity. PMID:20510374

  18. 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

    Holmes, David S.; And Others

    1980-01-01

    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)

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

    PubMed Central

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

    2013-01-01

    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. PMID:24187540

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

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

    PubMed Central

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

    2008-01-01

    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. PMID:19386046

  3. Audio-Visual and Autogenic Relaxation Alter Amplitude of Alpha EEG Band, Causing Improvements in Mental Work Performance in Athletes.

    PubMed

    Mikicin, Mirosław; Kowalczyk, Marek

    2015-09-01

    The aim of the present study was to investigate the effect of regular audio-visual relaxation combined with Schultz's autogenic training on: (1) the results of behavioral tests that evaluate work performance during burdensome cognitive tasks (Kraepelin test), (2) changes in classical EEG alpha frequency band, neocortex (frontal, temporal, occipital, parietal), hemisphere (left, right) versus condition (only relaxation 7-12 Hz). Both experimental (EG) and age-and skill-matched control group (CG) consisted of eighteen athletes (ten males and eight females). After 7-month training EG demonstrated changes in the amplitude of mean electrical activity of the EEG alpha bend at rest and an improvement was significantly changing and an improvement in almost all components of Kraepelin test. The same examined variables in CG were unchanged following the period without the intervention. Summing up, combining audio-visual relaxation with autogenic training significantly improves athlete's ability to perform a prolonged mental effort. These changes are accompanied by greater amplitude of waves in alpha band in the state of relax. The results suggest usefulness of relaxation techniques during performance of mentally difficult sports tasks (sports based on speed and stamina, sports games, combat sports) and during relax of athletes. PMID:26016588

  4. Sensitivity of Alpha and Beta Oscillations to Sensorimotor Characteristics of Action: An EEG Study of Action Production and Gesture Observation

    PubMed Central

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

    2012-01-01

    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

  5. Placebo Analgesia Changes Alpha Oscillations Induced by Tonic Muscle Pain: EEG Frequency Analysis Including Data during Pain Evaluation

    PubMed Central

    Li, Linling; Wang, Hui; Ke, Xijie; Liu, Xiaowu; Yuan, Yuan; Zhang, Deren; Xiong, Donglin; Qiu, Yunhai

    2016-01-01

    Placebo exhibits beneficial effects on pain perception in human experimental studies. Most of these studies demonstrate that placebo significantly decreased neural activities in pain modulatory brain regions and pain-evoked potentials. This study examined placebo analgesia-related effects on spontaneous brain oscillations. We examined placebo effects on four order-fixed 20-min conditions in two sessions: isotonic saline-induced control conditions (with/without placebo) followed by hypertonic saline-induced tonic muscle pain conditions (with/without placebo) in 19 subjects using continuous electroencephalography (EEG) recording. Placebo treatment exerted significant analgesic effects in 14 placebo responders, as subjective intensity of pain perception decreased. Frequency analyses were performed on whole continuous EEG data, data during pain perception rating and data after rating. The results in the first two cases revealed that placebo induced significant increases and a trend toward significant increases in the amplitude of alpha oscillation during tonic muscle pain compared to control conditions in frontal-central regions of the brain, respectively. Placebo-induced decreases in the subjective intensity of pain perception significantly and positively correlated with the increases in the amplitude of alpha oscillations during pain conditions. In conclusion, the modulation effect of placebo treatment was captured when the pain perception evaluating period was included. The strong correlation between the placebo effect on reported pain perception and alpha amplitude suggest that alpha oscillations in frontal-central regions serve as a cortical oscillatory basis of the placebo effect on tonic muscle pain. These results provide important evidence for the investigation of objective indicators of the placebo effect.

  6. Spectral features of EEG alpha activity in human REM sleep: two variants with different functional roles?

    PubMed

    Cantero, J L; Atienza, M; Salas, R M

    2000-09-15

    Evidence suggests that an important contribution of spectral power in the alpha range is characteristic of human REM sleep. This contribution is, in part, due to the appearance of well-defined bursts of alpha activity not associated with arousals during both tonic and phasic REM fragments. The present study aims at determining if the REM-alpha bursts constitute a different alpha variant from the REM background alpha activity. Since previous findings showed a selective suppression of background alpha activity over occipital regions during phasic REM fragments and, on the other hand, the density of alpha bursts seem to be independent of the presence or absence of rapid eye movements, one expects to find the same spectral power contribution of alpha bursts in tonic and phasic REM fragments. The results indicated that REM-alpha bursts showed a similar power contribution and topographic distribution (maximum energy over occipital regions) both in tonic and phasic REM fragments. This suggests that two variants of alpha activity with different functional roles are present during the human REM sleep: i) background alpha activity, modulated over occipital regions by the presence of rapid eye movements, which may be an electrophysiological correlate of the visual dream contents; and ii) REM-alpha bursts, independent of the presence of rapid eye movements, which could be facilitating the connection between the dreaming brain and the external world, working as a micro-arousal in this brain state. PMID:11007441

  7. Differential interaction between iron and mutant alpha-synuclein causes distinctive Parkinsonian phenotypes in Drosophila.

    PubMed

    Zhu, Zhou-Jing; Wu, Ka-Chun; Yung, Wing-Ho; Qian, Zhong-Ming; Ke, Ya

    2016-04-01

    Alpha-synuclein aggregation is the central hallmark of both sporadic and familial Parkinson's disease (PD). Patients with different PD-causing genetic defects of alpha-synuclein usually show distinctive clinical features that are atypical to sporadic PD. Iron accumulation is invariably found in PD. Recent studies showed that mutant and wild-type alpha-synuclein may have differential interaction with iron and mutant alpha-synuclein toxicity could be preferentially exacerbated by iron. We hence hypothesized that iron overload could selectively influence mutant alpha-synuclein toxicity and disease phenotypes. To test the hypothesis, we investigated if Drosophila melanogaster over-expressing A53T, A30P, and wild-type (WT) alpha-synuclein have different responses to iron treatment. We showed that iron treatment induced similar reduction of survival rate in all flies but induced a more severe motor decline in A53T and A30P mutant alpha-synuclein expressing flies, suggesting interaction between mutant alpha-synuclein and iron. Although no significant difference in total head iron content was found among these flies, we demonstrated that iron treatment induced selective DA neuron loss in motor-related PPM3 cluster only in the flies that express A53T and A30P mutant alpha-synuclein. We provided the first in vivo evidence that iron overload could induce distinctive neuropathology and disease phenotypes in mutant but not WT alpha-synuclein expressing flies, providing insights to the cause of clinical features selectively exhibited by mutant alpha-synuclein carriers. PMID:26769358

  8. Developmental aspects of language lateralization in delta, theta, alpha and beta EEG bands.

    PubMed

    Spironelli, Chiara; Angrilli, Alessandro

    2010-10-01

    This study aimed to clarify the functional role of several EEG bands across age by analyzing language hemispheric lateralization in three linguistic tasks. Twenty-eight children, 22 young adults and 20 middle-aged participants were administered the same sample of written words and normalized amplitudes of δ, ϑ, α and β bands were analyzed. Only young adults showed rightwards lateralization in δ frequency band. Task-dependent right-lateralization marked adults' ϑ and α distributions, whereas only linguistic vs. non-linguistic differences were found in children. Concerning the high-beta band, all groups showed left-lateralized linguistic effects. In adults slow rhythms represent indices of active inhibition of task-irrelevant regions, but in children they marked incomplete automated linguistic processing. The high-beta band revealed task-relevant left hemisphere linguistic activity in all groups, therefore representing the most reliable EEG marker of language hemispheric dominance in children and adults. PMID:20659528

  9. Alpha desynchronization and fronto-parietal connectivity during spatial working memory encoding deficits in ADHD: A simultaneous EEG-fMRI study.

    PubMed

    Lenartowicz, Agatha; Lu, Steven; Rodriguez, Cameron; Lau, Edward P; Walshaw, Patricia D; McCracken, James T; Cohen, Mark S; Loo, Sandra K

    2016-01-01

    The underlying mechanisms of alpha band (8-12 Hz) neural oscillations are of importance to the functioning of attention control systems as well as to neuropsychiatric conditions that are characterized by deficits of that system, such as attention deficit hyperactivity disorder (ADHD). The objectives of the present study were to test if visual encoding-related alpha event-related desynchronization (ERD) correlates with fronto-parieto-occipital connectivity, and whether this is disrupted in ADHD during spatial working memory (SWM) performance. We acquired EEG concurrently with fMRI in thirty boys (12-16 yrs. old, 15 with ADHD), during SWM encoding. Psychophysiological connectivity analyses indicated that alpha ERD during SWM encoding was associated with both occipital activation and fronto-parieto-occipital functional connectivity, a finding that expands on prior associations between alpha ERD and occipital activation. This finding provides novel support for the interpretation of alpha ERD (and the associated changes in occipital activation) as a phenomenon that involves, and perhaps arises as a result of, top-down network interactions. Alpha ERD was associated less strongly with occipital activity, but associated more strongly with fronto-parieto-occipital connectivity in ADHD, consistent with a compensatory attentional response. Additionally, we illustrate that degradation of EEG data quality by MRI-amplified motion artifacts is robust to existing cleaning algorithms and is significantly correlated with hyperactivity symptoms and the ADHD Combined Type diagnosis. We conclude that persistent motion-related MR artifacts in EEG data can increase variance and introduce bias in interpretation of group differences in populations characterized by hypermobility - a clear limitation of current-state EEG-fMRI methodology. PMID:26955516

  10. Effects of Heart Rate Variability Biofeedback on EEG Alpha Asymmetry and Anxiety Symptoms in Male Athletes: A Pilot Study.

    PubMed

    Dziembowska, Inga; Izdebski, Paweł; Rasmus, Anna; Brudny, Janina; Grzelczak, Marta; Cysewski, Piotr

    2016-06-01

    Heart rate variability biofeedback (HRV-BFB) has been shown as useful tool to manage stress in various populations. The present study was designed to investigate whether the biofeedback-based stress management tool consisting of rhythmic breathing, actively self-generated positive emotions and a portable biofeedback device induce changes in athletes' HRV, EEG patterns, and self-reported anxiety and self-esteem. The study involved 41 healthy male athletes, aged 16-21 (mean 18.34 ± 1.36) years. Participants were randomly divided into two groups: biofeedback and control. Athletes in the biofeedback group received HRV biofeedback training, athletes in the control group didn't receive any intervention. During the randomized controlled trial (days 0-21), the mean anxiety score declined significantly for the intervention group (change-4 p < 0.001) but not for the control group (p = 0.817). In addition, as compared to the control, athletes in biofeedback group showed substantial and statistically significant improvement in heart rate variability indices and changes in power spectra of both theta and alpha brain waves, and alpha asymmetry. These changes suggest better self-control in the central nervous system and better flexibility of the autonomic nervous system in the group that received biofeedback training. A HRV biofeedback-based stress management tool may be beneficial for stress reduction for young male athletes. PMID:26459346

  11. The Diagnostic Value of Alpha-1-Antitrypsin Phenotype in Patients with Granulomatosis with Polyangiitis

    PubMed Central

    2016-01-01

    The deficiency of alpha-1 protease inhibitor, or alpha-1-antitrypsin (A1AT), predisposes to chronic lung diseases and extrapulmonary pathology. Besides classical manifestations, such as pulmonary emphysema and liver disease, alpha-1-antitrypsin deficiency (A1ATD) is also known to be associated with granulomatosis with polyangiitis (GPA or Wegener's granulomatosis). The aim of our study was to evaluate the frequency of allelic isoforms of A1AT and their clinical significance among GPA patients. Detailed clinical information, including Birmingham Vasculitis Activity Score (BVAS), incidence of lung involvement, anti-proteinase 3 (PR3) antibodies concentrations, and other laboratory data were collected in 38 GPA patients. We also studied serum samples obtained from 46 healthy donors. In all collected samples A1AT phenotyping by isoelectrofocusing (IEF) and turbidimetric A1AT measurement were performed. Abnormal A1AT variants were found in 18.4% (7/38) of cases: 1 ZZ, 4 MZ, 2 MF, and only 1 MZ in control group (2%). The mean A1AT concentration in samples with atypical A1AT phenotypes was significantly lower (P = 0.0038) than in normal A1AT phenotype. We found that patients with abnormal A1AT phenotypes had significantly higher vasculitis activity (BVAS) as well as anti-PR3 antibodies concentration. We conclude that A1AT deficiency should be considered in all patients with GPA.

  12. Neural correlates underlying insight problem solving: Evidence from EEG alpha oscillations.

    PubMed

    Cao, Zhipeng; Li, Yadan; Hitchman, Glenn; Qiu, Jiang; Zhang, Qinglin

    2015-09-01

    Previous studies on insight problem solving using Chinese logogriphs as insight problems only investigated the time- and phase-locked changes of electrocortical responses triggered by Chinese logogriphs, but did not focus on what kind of brain state facilitates individuals to solve insight problems. To investigate this, we focused on participants' alpha activities (8-12 Hz) that closely correlates with insight problem solving and defocused attention while they were solving Chinese logogriphs. Results indicated that in the time window of 800-1400 ms after the presentation of target logogriphs, alpha power over parieto-central electrodes decreased relative to the reference interval in both the successful and unsuccessful logogriphs solving conditions. However, alpha power increased at parieto-occipital electrode sites in successful conditions compared with that in unsuccessful condition. The decrease in alpha activity in both conditions may reflect the cognitive demands in solving the target logogriphs. Furthermore, difference in alpha power between the successful and unsuccessful conditions at parieto-occipital electrode sites is associated with the process of heuristic information. Alpha synchronization observed in the successful condition compared to the unsuccessful condition might reflect a state of defocused attention that facilitates insight problem solving. PMID:26048161

  13. Phenotypic classification of male pseudohermaphroditism due to steroid 5{alpha}-reductase 2 deficiency

    SciTech Connect

    Sinnecker, G.H.G; Hiort, O.; Kruse, K.; Dibbelt, L.

    1996-05-03

    Conversion of testosterone (T) to dihydrotestosterone (DHT) in genital tissue is catalysed by the enzyme 5{alpha}-reductase 2, which is encoded by the SRD5A2 gene. The potent androgen DHT is required for full masculinization of the external genitalia. Mutations of the SRD5A2 gene inhibit enzyme activity, diminish DHT formation, and hence cause masculinization defects of varying degree. The classical syndrome, formerly described as pseudovaginal perineoscrotal hypospadias, is characterized by a predominantly female phenotype at birth and significant virilization without gynecomastia at puberty. We investigated nine patients with steroid 5{alpha}-reductase 2 deficiency (SRD). T/DHT-ratios were highly increased in the classical syndrome, but variable in the less severe affected patients. Mutations in the SRD5A2 gene had been characterized using PCR-SSCP analysis and direct DNA sequencing. A small deletion was encountered in two patients, while all other patients had single base mutations which result in amino acid substitutions. We conclude that phenotypes may vary widely in patients with SRD5A2 gene mutations spanning the whole range from completely female to normal male without distinctive clinical signs of the disease. Hence, steroid 5{alpha}-reductase deficiency should be considered not only in sex reversed patients with female or ambiguous phenotypes, but also in those with mild symptoms of undermasculinization as encountered in patients with hypospadias and/or micropenis. A classification based on the severity of the masculinization defect may be used for correlation of phenotypes with enzyme activities and genotypes, and for comparisons of phenotypes between different patients as the basis for clinical decisions to be made in patients with pseudohermaphroditism due to steroid 5{alpha}-reductase 2 deficiency. 22 refs., 2 figs., 2 tabs.

  14. Brief Report: Reduced Temporal-Central EEG Alpha Coherence during Joint Attention Perception in Adolescents with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Jaime, Mark; McMahon, Camilla M.; Davidson, Bridget C.; Newell, Lisa C.; Mundy, Peter C.; Henderson, Heather A.

    2016-01-01

    Although prior studies have demonstrated reduced resting state EEG coherence in adults with autism spectrum disorder (ASD), no studies have explored the nature of EEG coherence during joint attention. We examined the EEG coherence of the joint attention network in adolescents with and without ASD during congruent and incongruent joint attention…

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

    PubMed Central

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

    1980-01-01

    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. PMID:6772023

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

    PubMed Central

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

    2011-01-01

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

  17. Amino acid substitutions in the Dictyostelium G alpha subunit G alpha 2 produce dominant negative phenotypes and inhibit the activation of adenylyl cyclase, guanylyl cyclase, and phospholipase C.

    PubMed Central

    Okaichi, K; Cubitt, A B; Pitt, G S; Firtel, R A

    1992-01-01

    Previous studies have demonstrated that the Dictyostelium G alpha subunit G alpha 2 is essential for the cAMP-activation of adenylyl cyclase and guanylyl cyclase and that g alpha 2 null mutants do not aggregate. In this manuscript, we extend the analysis of the function of G alpha 2 in regulating downstream effectors by examining the in vivo developmental and physiological phenotypes of both wild-type and g alpha 2 null cells carrying a series of mutant G alpha 2 subunits expressed from the cloned G alpha 2 promoter. Our results show that wild-type cells expressing G alpha 2 subunits carrying mutations G40V and Q208L in the highly conserved GAGESG (residues 38-43) and GGQRS (residues 206-210) domains, which are expected to reduce the intrinsic GTPase activity, are blocked in multicellular development. Analysis of down-stream effector pathways essential for mediating aggregation indicates that cAMP-mediated activation of guanylyl cyclase and phosphatidylinositol-phospholipase C (PI-PLC) is almost completely inhibited and that there is a substantial reduction of cAMP-mediated activation of adenylyl cyclase. Moreover, neither mutant G alpha 2 subunit can complement g alpha 2 null mutants. Expression of G alpha 2(G43V) and G alpha 2(G207V) have little or no effect on the effector pathways and can partially complement g alpha 2 null cells. Our results suggest a model in which the dominant negative phenotypes resulting from the expression of G alpha 2(G40V) and G alpha 2(Q208L) are due to a constitutive adaptation of the effectors through a G alpha 2-mediated pathway. Analysis of PI-PLC in g alpha 2 null mutants and in cell lines expressing mutant G alpha 2 proteins also strongly suggests that G alpha 2 is the G alpha subunit that directly activates PI-PLC during aggregation. Moreover, overexpression of wild-type G alpha 2 results in the ability to precociously activate guanylyl cyclase by cAMP in vegetative cells, suggesting that G alpha 2 may be rate limiting in the developmental regulation of guanylyl cyclase activation. In agreement with previous results, the activation of adenylyl cyclase, while requiring G alpha 2 function in vivo, does not appear to be directly carried out by the G alpha 2 subunit. Our data are consistent with adenylyl cyclase being directly activated by either another G alpha subunit or by beta gamma subunits released on activation of the G protein containing G alpha 2. Images PMID:1355376

  18. Pupil Dilation and EEG Alpha Frequency Band Power Reveal Load on Executive Functions for Link-Selection Processes during Text Reading

    PubMed Central

    Scharinger, Christian; Kammerer, Yvonne; Gerjets, Peter

    2015-01-01

    Executive working memory functions play a central role in reading comprehension. In the present research we were interested in additional load imposed on executive functions by link-selection processes during computer-based reading. For obtaining process measures, we used a methodology of concurrent electroencephalographic (EEG) and eye-tracking data recording that allowed us to compare epochs of pure text reading with epochs of hyperlink-like selection processes in an online reading situation. Furthermore, this methodology allowed us to directly compare the two physiological load-measures EEG alpha frequency band power and pupil dilation. We observed increased load on executive functions during hyperlink-like selection processes on both measures in terms of decreased alpha frequency band power and increased pupil dilation. Surprisingly however, the two measures did not correlate. Two additional experiments were conducted that excluded potential perceptual, motor, or structural confounds. In sum, EEG alpha frequency band power and pupil dilation both turned out to be sensitive measures for increased load during hyperlink-like selection processes in online text reading. PMID:26076026

  19. Pupil Dilation and EEG Alpha Frequency Band Power Reveal Load on Executive Functions for Link-Selection Processes during Text Reading.

    PubMed

    Scharinger, Christian; Kammerer, Yvonne; Gerjets, Peter

    2015-01-01

    Executive working memory functions play a central role in reading comprehension. In the present research we were interested in additional load imposed on executive functions by link-selection processes during computer-based reading. For obtaining process measures, we used a methodology of concurrent electroencephalographic (EEG) and eye-tracking data recording that allowed us to compare epochs of pure text reading with epochs of hyperlink-like selection processes in an online reading situation. Furthermore, this methodology allowed us to directly compare the two physiological load-measures EEG alpha frequency band power and pupil dilation. We observed increased load on executive functions during hyperlink-like selection processes on both measures in terms of decreased alpha frequency band power and increased pupil dilation. Surprisingly however, the two measures did not correlate. Two additional experiments were conducted that excluded potential perceptual, motor, or structural confounds. In sum, EEG alpha frequency band power and pupil dilation both turned out to be sensitive measures for increased load during hyperlink-like selection processes in online text reading. PMID:26076026

  20. Spontaneous EEG alpha oscillation interacts with positive and negative BOLD responses in the visual-auditory cortices and default-mode network.

    PubMed

    Mayhew, Stephen D; Ostwald, Dirk; Porcaro, Camillo; Bagshaw, Andrew P

    2013-08-01

    The human brain is continually, dynamically active and spontaneous fluctuations in this activity play a functional role in affecting both behavioural and neuronal responses. However, the mechanisms through which this occurs remain poorly understood. Simultaneous EEG-fMRI is a promising technique to study how spontaneous activity modulates the brain's response to stimulation, as temporal indices of ongoing cortical excitability can be integrated with spatially localised evoked responses. Here we demonstrate an interaction between the ongoing power of the electrophysiological alpha oscillation and the magnitude of both positive (PBR) and negative (NBR) fMRI responses to two contrasts of visual checkerboard reversal. Furthermore, the amplitude of pre-stimulus EEG alpha-power significantly modulated the amplitude and shape of subsequent PBR and NBR to the visual stimulus. A nonlinear reduction of visual PBR and an enhancement of auditory NBR and default-mode network NBR were observed in trials preceded by high alpha-power. These modulated areas formed a functionally connected network during a separate resting-state recording. Our findings suggest that the "baseline" state of the brain exhibits considerable trial-to-trial variability which arises from fluctuations in the balance of cortical inhibition/excitation that are represented by respective increases/decreases in the power of the EEG alpha oscillation. The consequence of this spontaneous electrophysiological variability is modulated amplitudes of both PBR and NBR to stimulation. Fluctuations in alpha-power may subserve a functional relationship in the visual-auditory network, acting as mediator for both short and long-range cortical inhibition, the strength of which is represented in part by NBR. PMID:23507378

  1. 'SZ like' alpha 1-antitrypsin phenotypes in PI ZZ children with liver disease.

    PubMed

    Whitehouse, D B; Lovegrove, J U; Mieli-Vergani, G; Mowat, A P; Hopkinson, D A

    1994-01-01

    Using high resolution isoelectric focusing, alpha 1-antitrypsin phenotypes were studied in 106 individuals of the PI ZZ genotype including 71 with liver disease, 22 with chest disease and 13 healthy subjects. The resulting Z patterns were found to be highly variable. In the majority of cases (89/106) the maximum staining intensity was either in the most basic isoform or shared equally between two basic isoforms of the Z phenotype. However, in 17 cases there was a marked intensification of the more acidic isoforms resulting in a pattern which closely resembled the SZ phenotype. This 'SZ like' pattern occurred more frequently in the liver group (16/71) than the chest group (0/22) or healthy (1/13) controls. One possible consequence of the 'SZ like' pattern is confusion with the genuine SZ phenotype leading to misclassification. If this were so, there could be an erroneous exaggeration of the actual incidence of childhood liver disease associated with PI SZ. PMID:8031012

  2. Atrophy and lower regional perfusion of temporo-parietal brain areas are correlated with impairment in memory performances and increase of EEG upper alpha power in prodromal Alzheimer’s disease

    PubMed Central

    Moretti, Vito Davide

    2015-01-01

    Background: Temporo-parietal cortex thinning is associated with mild cognitive impairment (MCI) due to Alzheimer’s disease (AD). The increase of the EEG upper/low alpha power ratio has been associated with MCI due to AD subjects and to the atrophy of temporo-parietal brain areas. Moreover, subjects with a higher alpha3/alpha2 frequency power ratio showed lower brain perfusion than in the low alpha3/alpha2 group. The two groups have significantly different hippocampal volumes and correlation with the theta frequency activity. Methods: 74 adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording, and high resolution 3D magnetic resonance imaging (MRI). 27 of them underwent EEG recording and perfusion single-photon emission computed tomography (SPECT) evaluation. The alpha3/alpha2 power ratio as well as cortical thickness was computed for each subject. The difference in cortical thickness between the groups was estimated. Pearson’s r was used to assess the correlation topography between cortical thinning as well as between brain perfusion and memory impairment. Results: In the higher upper/low alpha group, memory impairment was more pronounced both in the MRI group and the SPECT MCI group. Moreover, it was correlated with greater cortical atrophy and lower perfusional rate in temporo-parietal cortex. Conclusion: High EEG upper/low alpha power ratio was associated with cortical thinning lower perfusion in temporo-parietal. Moreover, atrophy and lower perfusional rate were both significantly correlated with memory impairment in MCI subjects. The increase of EEG upper/low alpha frequency power ratio could be useful for identifying individuals at risk for progression to AD dementia and may be of value in the clinical context. PMID:26389016

  3. Resting state glutamate predicts elevated pre-stimulus alpha during self-relatedness: A combined EEG-MRS study on "rest-self overlap".

    PubMed

    Bai, Yu; Nakao, Takashi; Xu, Jiameng; Qin, Pengmin; Chaves, Pedro; Heinzel, Alexander; Duncan, Niall; Lane, Timothy; Yen, Nai-Shing; Tsai, Shang-Yueh; Northoff, Georg

    2016-06-01

    Recent studies have demonstrated neural overlap between resting state activity and self-referential processing. This "rest-self" overlap occurs especially in anterior cortical midline structures like the perigenual anterior cingulate cortex (PACC). However, the exact neurotemporal and biochemical mechanisms remain to be identified. Therefore, we conducted a combined electroencephalography (EEG)-magnetic resonance spectroscopy (MRS) study. EEG focused on pre-stimulus (e.g., prior to stimulus presentation or perception) power changes to assess the degree to which those changes can predict subjects' perception (and judgment) of subsequent stimuli as high or low self-related. MRS measured resting state concentration of glutamate, focusing on PACC. High pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power significantly correlated with both perception of stimuli judged to be highly self-related and with resting state glutamate concentrations in the PACC. In sum, our results show (i) pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power and resting state glutamate concentration to mediate rest-self overlap that (ii) dispose or incline subjects to assign high degrees of self-relatedness to perceptual stimuli. PMID:26207415

  4. Alpha1-antitrypsin phenotypes and lung function in a moderately polluted northern Ontario community.

    PubMed Central

    Ostrow, D. N.; Manfreda, J.; Dorman, T.; Cherniack, R. M.

    1978-01-01

    To determine whether persons with intermediate value alpha1-antitrypsin phenotypes living in a polluted environment manifest significant abnormalities in lung function, a study was undertaken of an age-, sex- and smoking-stratified sample of 391 persons from the town of Fort Frances, Ont., which has elevated values of total dustfall, suspended particulates and hydrogen sulfide. Indices of pulmonary function were derived from the maximum expiratory flow and the single breath expiratory flow and the single breath expiratory nitrogen washout curves. The percentage frequency of the M, MS and MZ pheontypes was 91.7, 7.3 and 0.8, respectively. There was no significant difference between the M and MS groups as indicated by the nitrogen washout curve and maximum expiratory flow curve. There was no significant difference between the three MZ subjects and the M group. In both M and MS groups smokers displayed evidence of airflow obstruction when compared with nonsmokers. It would appear that, when compared with M subjects, persons with the MS phenotype living in a moderately polluted area show no changes in indicators of pulmonary function, including tests of early airway disease, that cannot be attributed to their smoking habit. PMID:306869

  5. Alpha1-antitrypsin phenotypes and lung function in a moderately polluted northern Ontario community.

    PubMed

    Ostrow, D N; Manfreda, J; Dorman, T; Cherniack, R M

    1978-03-18

    To determine whether persons with intermediate value alpha1-antitrypsin phenotypes living in a polluted environment manifest significant abnormalities in lung function, a study was undertaken of an age-, sex- and smoking-stratified sample of 391 persons from the town of Fort Frances, Ont., which has elevated values of total dustfall, suspended particulates and hydrogen sulfide. Indices of pulmonary function were derived from the maximum expiratory flow and the single breath expiratory flow and the single breath expiratory nitrogen washout curves. The percentage frequency of the M, MS and MZ pheontypes was 91.7, 7.3 and 0.8, respectively. There was no significant difference between the M and MS groups as indicated by the nitrogen washout curve and maximum expiratory flow curve. There was no significant difference between the three MZ subjects and the M group. In both M and MS groups smokers displayed evidence of airflow obstruction when compared with nonsmokers. It would appear that, when compared with M subjects, persons with the MS phenotype living in a moderately polluted area show no changes in indicators of pulmonary function, including tests of early airway disease, that cannot be attributed to their smoking habit. PMID:306869

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

    PubMed Central

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

    2013-01-01

    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. PMID:19617216

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

    SciTech Connect

    Villard, L.; Lossi, A.M.; Fontes, M.

    1996-03-01

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

  8. Regional electroencephalogram (EEG) alpha power and asymmetry in older adults: a study of short-term test–retest reliability

    PubMed Central

    Mathewson, Karen J.; Hashemi, Ali; Sheng, Bruce; Sekuler, Allison B.; Bennett, Patrick J.; Schmidt, Louis A.

    2015-01-01

    Although regional alpha power and asymmetry measures have been widely used as indices of individual differences in emotional processing and affective style in younger populations, there have been relatively few studies that have examined these measures in older adults. Here, we examined the short-term test–retest reliability of resting regional alpha power (7.5–12.5 Hz) and asymmetry in a sample of 38 active, community-dwelling older adults (M age = 71.2, SD = 6.5 years). Resting electroencephalogram recordings were made before and after a perceptual computer task. Pearson and intra-class correlations indicated acceptable test–retest reliability for alpha power and asymmetry measures in all regions. Interestingly, alpha asymmetry appeared to be less affected by the task than was alpha power. Findings suggest that alpha asymmetry may reflect more enduring, “trait-like” characteristics, while alpha power may reflect more “state-like” processes in older adults. PMID:26441639

  9. EEG, ERPs and food consumption.

    PubMed

    Hoffman, L D; Polich, J

    1998-06-01

    Baseline electroencephalographic (EEG) and auditory event-related brain potentials (ERPs) were assessed in subjects before and after consuming food and under eyes open and closed recording conditions in an attempt to replicate and extend previous food--ERP effects. Subjects were assessed the morning after fasting from the previous night, before and after eating a standard lunch. Delta- band EEG spectral power decreased and theta- and early alpha-band frequency increased after food consumption. However, in contrast to previous reports, P300 amplitude was unaffected by food consumption and peak latency increased. The strength of the correlational association between background EEG activity and P300 measures decreased for the delta- and theta- bands, but increased for the early and late alpha- bands. The findings suggest that food consumption affects general arousal, rather than specific cognitive EEG or ERP factors and are discussed with respect to previous EEG-ERP findings on food intake. PMID:9700015

  10. EEG synchronization and migraine

    NASA Astrophysics Data System (ADS)

    Stramaglia, Sebastiano; Angelini, Leonardo; Pellicoro, Mario; Hu, Kun; Ivanov, Plamen Ch.

    2004-03-01

    We investigate phase synchronization in EEG recordings from migraine patients. We use the analytic signal technique, based on the Hilbert transform, and find that migraine brains are characterized by enhanced alpha band phase synchronization in presence of visual stimuli. Our findings show that migraine patients have an overactive regulatory mechanism that renders them more sensitive to external stimuli.

  11. Auditory cortical deactivation during speech production and following speech perception: an EEG investigation of the temporal dynamics of the auditory alpha rhythm

    PubMed Central

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

    2015-01-01

    Sensorimotor integration (SMI) across the dorsal stream enables online monitoring of speech. Jenson et al. (2014) used independent component analysis (ICA) and event related spectral perturbation (ERSP) analysis of electroencephalography (EEG) data to describe anterior sensorimotor (e.g., premotor cortex, PMC) activity during speech perception and production. The purpose of the current study was to identify and temporally map neural activity from posterior (i.e., auditory) regions of the dorsal stream in the same tasks. Perception tasks required “active” discrimination of syllable pairs (/ba/ and /da/) in quiet and noisy conditions. Production conditions required overt production of syllable pairs and nouns. ICA performed on concatenated raw 68 channel EEG data from all tasks identified bilateral “auditory” alpha (α) components in 15 of 29 participants localized to pSTG (left) and pMTG (right). ERSP analyses were performed to reveal fluctuations in the spectral power of the α rhythm clusters across time. Production conditions were characterized by significant α event related synchronization (ERS; pFDR < 0.05) concurrent with EMG activity from speech production, consistent with speech-induced auditory inhibition. Discrimination conditions were also characterized by α ERS following stimulus offset. Auditory α ERS in all conditions temporally aligned with PMC activity reported in Jenson et al. (2014). These findings are indicative of speech-induced suppression of auditory regions, possibly via efference copy. The presence of the same pattern following stimulus offset in discrimination conditions suggests that sensorimotor contributions following speech perception reflect covert replay, and that covert replay provides one source of the motor activity previously observed in some speech perception tasks. To our knowledge, this is the first time that inhibition of auditory regions by speech has been observed in real-time with the ICA/ERSP technique. PMID:26500519

  12. Auditory cortical deactivation during speech production and following speech perception: an EEG investigation of the temporal dynamics of the auditory alpha rhythm.

    PubMed

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

    2015-01-01

    Sensorimotor integration (SMI) across the dorsal stream enables online monitoring of speech. Jenson et al. (2014) used independent component analysis (ICA) and event related spectral perturbation (ERSP) analysis of electroencephalography (EEG) data to describe anterior sensorimotor (e.g., premotor cortex, PMC) activity during speech perception and production. The purpose of the current study was to identify and temporally map neural activity from posterior (i.e., auditory) regions of the dorsal stream in the same tasks. Perception tasks required "active" discrimination of syllable pairs (/ba/ and /da/) in quiet and noisy conditions. Production conditions required overt production of syllable pairs and nouns. ICA performed on concatenated raw 68 channel EEG data from all tasks identified bilateral "auditory" alpha (α) components in 15 of 29 participants localized to pSTG (left) and pMTG (right). ERSP analyses were performed to reveal fluctuations in the spectral power of the α rhythm clusters across time. Production conditions were characterized by significant α event related synchronization (ERS; pFDR < 0.05) concurrent with EMG activity from speech production, consistent with speech-induced auditory inhibition. Discrimination conditions were also characterized by α ERS following stimulus offset. Auditory α ERS in all conditions temporally aligned with PMC activity reported in Jenson et al. (2014). These findings are indicative of speech-induced suppression of auditory regions, possibly via efference copy. The presence of the same pattern following stimulus offset in discrimination conditions suggests that sensorimotor contributions following speech perception reflect covert replay, and that covert replay provides one source of the motor activity previously observed in some speech perception tasks. To our knowledge, this is the first time that inhibition of auditory regions by speech has been observed in real-time with the ICA/ERSP technique. PMID:26500519

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

    SciTech Connect

    Naiki, Takafumi; Nagaki, Masahito . E-mail: mnagaki@cc.gifu-u.ac.jp; Asano, Takahiko; Kimata, Takayuki; Moriwaki, Hisataka

    2005-09-23

    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.

  14. COMT polymorphism modulates the resting-state EEG alpha oscillatory response to acute nicotine in male non-smokers

    PubMed Central

    Bowers, H.; Smith, D.; de la Salle, S.; Choueiry, J.; Impey, D.; Philippe, T.; Dort, H.; Millar, A.; Daigle, M.; Albert, P. R.; Beaudoin, A.; Knott, V.

    2015-01-01

    Performance improvements in cognitive tasks requiring executive functions are evident with nicotinic acetylcholine receptor (nAChR) agonists, and activation of the underlying neural circuitry supporting these cognitive effects is thought to involve dopamine neurotransmission. As individual difference in response to nicotine may be related to a functional polymorphism in the gene encoding catechol-O-methyltransferase (COMT), an enzyme that strongly influences cortical dopamine metabolism, this study examined the modulatory effects of the COMT Val158Met polymorphism on the neural response to acute nicotine as measured with resting-state electroencephalographic (EEG) oscillations. In a sample of 62 healthy non-smoking adult males, a single dose (6 mg) of nicotine gum administered in a randomized, double-blind, placebo-controlled design was shown to affect α oscillatory activity, increasing power of upper α oscillations in frontocentral regions of Met/Met homozygotes and in parietal/occipital regions of Val/Met heterozygotes. Peak α frequency was also found to be faster with nicotine (vs. placebo) treatment in Val/Met heterozygotes, who exhibited a slower α frequency compared to Val/Val homozygotes. The data tentatively suggest that interindividual differences in brain α oscillations and their response to nicotinic agonist treatment are influenced by genetic mechanisms involving COMT. PMID:26096691

  15. COMT polymorphism modulates the resting-state EEG alpha oscillatory response to acute nicotine in male non-smokers.

    PubMed

    Bowers, H; Smith, D; de la Salle, S; Choueiry, J; Impey, D; Philippe, T; Dort, H; Millar, A; Daigle, M; Albert, P R; Beaudoin, A; Knott, V

    2015-07-01

    Performance improvements in cognitive tasks requiring executive functions are evident with nicotinic acetylcholine receptor (nAChR) agonists, and activation of the underlying neural circuitry supporting these cognitive effects is thought to involve dopamine neurotransmission. As individual difference in response to nicotine may be related to a functional polymorphism in the gene encoding catechol-O-methyltransferase (COMT), an enzyme that strongly influences cortical dopamine metabolism, this study examined the modulatory effects of the COMT Val158Met polymorphism on the neural response to acute nicotine as measured with resting-state electroencephalographic (EEG) oscillations. In a sample of 62 healthy non-smoking adult males, a single dose (6 mg) of nicotine gum administered in a randomized, double-blind, placebo-controlled design was shown to affect α oscillatory activity, increasing power of upper α oscillations in frontocentral regions of Met/Met homozygotes and in parietal/occipital regions of Val/Met heterozygotes. Peak α frequency was also found to be faster with nicotine (vs. placebo) treatment in Val/Met heterozygotes, who exhibited a slower α frequency compared to Val/Val homozygotes. The data tentatively suggest that interindividual differences in brain α oscillations and their response to nicotinic agonist treatment are influenced by genetic mechanisms involving COMT. PMID:26096691

  16. Fabry disease: thirty-five mutations in the alpha-galactosidase A gene in patients with classic and variant phenotypes.

    PubMed Central

    Eng, C. M.; Ashley, G. A.; Burgert, T. S.; Enriquez, A. L.; D'Souza, M.; Desnick, R. J.

    1997-01-01

    BACKGROUND: Fabry disease, an X-linked inborn error of glycosphingolipid catabolism, results from mutations in the alpha-galactosidase A (alpha-Gal A) gene located at Xq22.1. To determine the nature and frequency of the molecular lesions causing the classical and milder variant Fabry phenotypes and for precise carrier detection, the alpha-Gal A lesions in 42 unrelated Fabry hemizygotes were determined. MATERIALS AND METHODS: Genomic DNA was isolated from affected probands and their family members. The seven alpha-galactosidase A exons and flanking intronic sequences were PCR amplified and the nucleotide sequence was determined by solid-phase direct sequencing. RESULTS: Two patients with the mild cardiac phenotype had missense mutations, I9IT and F113L, respectively. In 38 classically affected patients, 33 new mutations were identified including 20 missense (MIT, A31V, H46R, Y86C, L89P, D92Y, C94Y, A97V, R100T, Y134S, G138R, A143T, S148R, G163V, D170V, C202Y, Y216D, N263S, W287C, and N298S), two nonsense (Q386X, W399X), one splice site mutation (IVS4 + 2T-->C), and eight small exonic insertions or deletions (304del1, 613del9, 777del1, 1057del2, 1074del2, 1077del1, 1212del3, and 1094ins1), which identified exon 7 as a region prone to gene rearrangements. In addition, two unique complex rearrangements consisting of contiguous small insertions and deletions were found in exons 1 and 2 causing L45R/H46S and L120X, respectively. CONCLUSIONS: These studies further define the heterogeneity of mutations causing Fabry disease, permit precise carrier identification and prenatal diagnosis in these families, and facilitate the identification of candidates for enzyme replacement therapy. Images FIG. 2 PMID:9100224

  17. Lipid metabolism during aging of high-alpha-linolenate-phenotype potato tubers.

    PubMed

    Zabrouskov, Vladimir; Knowles, N Richard

    2002-06-01

    Previous studies demonstrated that high levels of alpha-linolenate in cell membranes of potato tubers (achieved by overexpressing fatty acid desaturases) enhances lipid peroxidation, oxidative stress, and tuber metabolic rate, effectively accelerating the physiological age of tubers. This study details the changes in lipid molecular species of microsomal and mitochondrial membranes from wild-type (WT) and high-alpha-linolenate tubers during aging. The microsomal and mitochondrial polar lipids of high-alpha-linolenate tubers were dominated by 18:3/18:3 and 16:0/18:3 molecular species. Relative to WT tubers, high-alpha-linolenate tubers had a substantially higher 16:0/18:n to 18:n/18:n molecular species ratio in mitochondria and microsomes, potentially reflecting a compensatory response to maintain membrane biophysical properties in the face of increased unsaturation. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) accounted for 53 and 37% of polar lipids, respectively, in mitochondria from younger WT and high-alpha-linolenate tubers. The relative proportions of these phospholipids (PL) did not change during aging of WT tubers. In contrast, PE increased to dominate the PL pool of mitochondria during aging of high-alpha-linolenate tubers. While aging effected an increase in mitochondrial 18:3-bearing PCs and PEs in WT tubers, the concentration of 18:3-bearing PCs fell with a concomitant increase in 18:3-bearing PEs during aging of high-alpha-linolenate tubers. These age- and high-alpha-linolenate-induced changes had no effect on the respiration rate and functional integrity of isolated mitochondria. Differential increases in the respiration rates of WT and high-alpha-linolenate tubers during aging were therefore a consequence of unsaturation-dependent alterations in the microenvironments of cells. Microsomal 18:3-bearing PCs, PEs, digalactosyldiacylglycerols (DGDG), and monogalactosyldiacylglycerols all increased in WT tubers during aging. In contrast, a selective loss of 18:3-bearing PCs and DGDGs from microsomes of high-alpha-linolenate tubers likely reflects a greater susceptibility of membranes to peroxidative catabolism during aging. Aging resulted in an increase in sterol/PL ratio in microsomes from WT tubers, due primarily to a decline in PL. In high-alpha-linolenate tubers, the increase in sterol/PL ratio during aging was due to increases in Delta 5-avenasterol and stigmasterol, indicating membrane rigidification and likely contributing to increased membrane permeability. Age-induced changes in 18:3-bearing lipids in membranes of transformed tubers are discussed relative to the development of oxidative stress and accelerated aging. PMID:12051691

  18. Interferon-alpha and interferon-gamma differentially affect pancreatic beta-cell phenotype and function.

    PubMed

    Baldeón, M E; Chun, T; Gaskins, H R

    1998-07-01

    To better clarify individual roles of interferon (IFN)-alpha and IFN-gamma in beta-cell pathology during the onset of type 1 diabetes mellitus, we compared the effects of these cytokines on insulin production and major histocompatibility complex (MHC) gene expression in pancreatic beta-cell lines. IFN-gamma but not IFN-alpha decreased secreted and intracellular insulin concentrations in betaTC6-F7 and betaTC3 cells. Likewise, IFN-gamma but not IFN-alpha treatment of beta-cells upregulated mRNA expression of MHC class IA antigen-processing genes and surface expression of class IA molecules. Alternatively, class IA MHC expression was upregulated by IFN-gamma and IFN-alpha in the P388D1 macrophage cell line. The observation of constitutive Ifn-alpha6 mRNA expression by a differentiated beta-cell line substantiates previous indications that local expression of IFN-alpha in islets may trigger insulitis. Evidence that IFN-gamma, a product of infiltrating leukocytes, directly decreases beta-cell glucose sensitivity and increases MHC class IA cell surface expression supports the postulate that IFN-gamma magnifies the insulitic process. PMID:9688831

  19. CRB2 Mutations Produce a Phenotype Resembling Congenital Nephrosis, Finnish Type, with Cerebral Ventriculomegaly and Raised Alpha-Fetoprotein

    PubMed Central

    Slavotinek, Anne; Kaylor, Julie; Pierce, Heather; Cahr, Michelle; DeWard, Stephanie J.; Schneidman-Duhovny, Dina; Alsadah, Adnan; Salem, Fadi; Schmajuk, Gabriela; Mehta, Lakshmi

    2015-01-01

    We report five fetuses and a child from three families who shared a phenotype comprising cerebral ventriculomegaly and echogenic kidneys with histopathological findings of congenital nephrosis. The presenting features were greatly elevated maternal serum alpha-fetoprotein (MSAFP) or amniotic fluid alpha-fetoprotein (AFAFP) levels or abnormalities visualized on ultrasound scan during the second trimester of pregnancy. Exome sequencing revealed deleterious sequence variants in Crumbs, Drosophila, Homolog of, 2 (CRB2) consistent with autosomal-recessive inheritance. Two fetuses with cerebral ventriculomegaly and renal microcysts were compound heterozygotes for p.Asn800Lys and p.Trp759Ter, one fetus with renal microcysts was a compound heterozygote for p.Glu643Ala and p.Asn800Lys, and one child with cerebral ventriculomegaly, periventricular heterotopias, echogenic kidneys, and renal failure was homozygous for p.Arg633Trp in CRB2. Examination of the kidneys in one fetus showed tubular cysts at the corticomedullary junction and diffuse effacement of the epithelial foot processes and microvillous transformation of the renal podocytes, findings that were similar to those reported in congenital nephrotic syndrome, Finnish type, that is caused by mutations in nephrin (NPHS1). Loss of function for crb2b and nphs1 in Danio rerio were previously shown to result in loss of the slit diaphragms of the podocytes, leading to the hypothesis that nephrosis develops from an inability to develop a functional glomerular barrier. We conclude that the phenotype associated with CRB2 mutations is pleiotropic and that the condition is an important consideration in the evaluation of high MSAFP/AFAFP where a renal cause is suspected. PMID:25557780

  20. P2Y receptor signaling regulates phenotype and IFN-alpha secretion of human plasmacytoid dendritic cells.

    PubMed

    Shin, Amanda; Toy, Tracey; Rothenfusser, Simon; Robson, Neil; Vorac, Julia; Dauer, Marc; Stuplich, Moritz; Endres, Stefan; Cebon, Jonathan; Maraskovsky, Eugene; Schnurr, Max

    2008-03-15

    Plasmacytoid dendritic cells (PDCs) play powerful regulatory roles in innate and adaptive immune responses and are a major source of type I interferon (IFN) following viral infection. During inflammation and mechanical stress, cells release nucleotides into the extracellular space where they act as signaling molecules via G protein-coupled P2Y receptors. We have previously reported on the regulation of myeloid dendritic cell (DC) function by nucleotides. Here, we report that human PDCs express several subtypes of P2Y receptors and mobilize intracellular calcium in response to nucleotide exposure. As a functional consequence, PDCs acquire a mature phenotype that is further enhanced in the context of CD40 ligation. Strikingly, nucleotides strongly inhibit IFN-alpha secretion induced by influenza virus or CpG-A. This effect is most pronounced for the uridine nucleotides UDP and UTP and the sugar nucleotide UDP-glucose, ligands of P2Y(6), P2Y(4), and P2Y(14), respectively. Nucleotide-induced inhibition of IFN-alpha production is blocked by suramin, a P2Y receptor antagonist. Pharmacological data point toward a role of protein kinase C in the negative regulation of type I IFN. Manipulating PDC function with P2Y receptor agonists may offer novel therapeutic strategies for autoimmune diseases or cancer. PMID:17993619

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

    SciTech Connect

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

    1988-06-24

    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.

  2. Identification of distinct human invariant natural killer T-cell response phenotypes to alpha-galactosylceramide

    PubMed Central

    Croudace, Joanne E; Curbishley, Stuart M; Mura, Manuela; Willcox, Carrie R; Illarionov, Petr A; Besra, Gurdyal S; Adams, David H; Lammas, David A

    2008-01-01

    Background Human CD1d-restricted, invariant natural killer T cells (iNKT) are a unique class of T lymphocytes that recognise glycolipid antigens such as ?-galactosylceramide (?GalCer) and upon T cell receptor (TCR) activation produce both Th1 and Th2 cytokines. iNKT cells expand when cultured in-vitro with ?GalCer and interleukin 2 (IL-2) in a CD1d-restricted manner. However, the expansion ratio of human iNKT cells varies between individuals and this has implications for attempts to manipulate this pathway therapeutically. We have studied a panel of twenty five healthy human donors to assess the variability in their in-vitro iNKT cell expansion responses to stimulation with CD1d ligands and investigated some of the factors that may influence this phenomenon. Results Although all donors had comparable numbers of circulating iNKT cells their growth rates in-vitro over 14 days in response to a range of CD1d ligands and IL-2 were highly donor-dependent. Two reproducible donor response patterns of iNKT expansion were seen which we have called 'strong' or 'poor' iNKT responders. Donor response phenotype did not correlate with age, gender, frequency of circulating iNKT, or with the CD1d ligand utilised. Addition of exogenous recombinant human interleukin 4 (IL-4) to 'poor' responder donor cultures significantly increased their iNKT proliferative capacity, but not to levels equivalent to that of 'strong' responder donors. However in 'strong' responder donors, addition of IL-4 to their cultures did not significantly alter the frequency of iNKT cells in the expanded CD3+ population. Conclusion (i) in-vitro expansion of human iNKT cells in response to CD1d ligand activation is highly donor variable, (ii) two reproducible patterns of donor iNKT expansion were observed, which could be classified into 'strong' and 'poor' responder phenotypes, (iii) donor iNKT response phenotypes did not correlate with age, gender, frequency of circulating iNKT cells, or with the CD1d ligand utilised, (iv) addition of IL-4 to 'poor' but not 'strong' responder donor cultures significantly increased their in-vitro iNKT cell expansion to ?GalCer. PMID:19055753

  3. EEG Recorded from the Ear: Characterizing the Ear-EEG Method

    PubMed Central

    Mikkelsen, Kaare B.; Kappel, Simon L.; Mandic, Danilo P.; Kidmose, Preben

    2015-01-01

    Highlights Auditory middle and late latency responses can be recorded reliably from ear-EEG.For sources close to the ear, ear-EEG has the same signal-to-noise-ratio as scalp.Ear-EEG is an excellent match for power spectrum-based analysis. A method for measuring electroencephalograms (EEG) from the outer ear, so-called ear-EEG, has recently been proposed. The method could potentially enable robust recording of EEG in natural environments. The objective of this study was to substantiate the ear-EEG method by using a larger population of subjects and several paradigms. For rigor, we considered simultaneous scalp and ear-EEG recordings with common reference. More precisely, 32 conventional scalp electrodes and 12 ear electrodes allowed a thorough comparison between conventional and ear electrodes, testing several different placements of references. The paradigms probed auditory onset response, mismatch negativity, auditory steady-state response and alpha power attenuation. By comparing event related potential (ERP) waveforms from the mismatch response paradigm, the signal measured from the ear electrodes was found to reflect the same cortical activity as that from nearby scalp electrodes. It was also found that referencing the ear-EEG electrodes to another within-ear electrode affects the time-domain recorded waveform (relative to scalp recordings), but not the timing of individual components. It was furthermore found that auditory steady-state responses and alpha-band modulation were measured reliably with the ear-EEG modality. Finally, our findings showed that the auditory mismatch response was difficult to monitor with the ear-EEG. We conclude that ear-EEG yields similar performance as conventional EEG for spectrogram-based analysis, similar timing of ERP components, and equal signal strength for sources close to the ear. Ear-EEG can reliably measure activity from regions of the cortex which are located close to the ears, especially in paradigms employing frequency-domain analyses. PMID:26635514

  4. Developing of EEG print and its preliminary technical application.

    PubMed

    Takigawa, M; Fukuzako, H; Ueyama, K; Takeuchi, K; Fukuzako, T; Nomaguchi, M

    1994-03-01

    In this report, we discuss a method called "EEG print" to represent EEG contrast mapping in time and frequency domains simultaneously. A bank of bandpass FIR (Finite Impulse Response) digital filters is used to obtain EEG prints. EEG prints were taken from four areas (F3, F4, O1 and O2) of EEG when healthy subjects were at rest with their eyes closed. The pattern of the prints was classified into four types: alpha type, beta type, alpha + beta type and complex type. It was found that EEG prints may vary from person-to-person but they usually do not vary much between the four areas for a given person. The method is further modified to obtain "differential EEG prints" to investigate whether meaningful higher frequency EEG components exist. Differentiation of EEG resulted in marked intensification of the fast waves, using 0.14 Hz as the critical point. In differential EEG print with higher order differentiation, amplification in the high frequency components increase their frequency. As a result, it is possible to observe variations in the high frequency components, which are otherwise not detectable in the usual EEG print. EEG print can be used for representing the function of the brain. Using the method for classification of EEG print patterns, described in this paper, we can clarify not only the characteristics of the normal brain but also the pathophysiology of mentally-ill patients. PMID:7933722

  5. Overexpression of synphilin-1 promotes clearance of soluble and misfolded alpha-synuclein without restoring the motor phenotype in aged A30P transgenic mice.

    PubMed

    Casadei, Nicolas; Pöhler, Anne-Maria; Tomás-Zapico, Cristina; Torres-Peraza, Jesús; Schwedhelm, Ivo; Witz, Annemarie; Zamolo, Irina; De Heer, Raymond; Spruijt, Berry; Noldus, Lucas P J J; Klucken, Jochen; Lucas, José J; Kahle, Philipp J; Krüger, Rejko; Riess, Olaf; Nuber, Silke

    2014-02-01

    Lewy bodies and neurites are the pathological hallmark of Parkinson's disease. These structures are composed of fibrillized and ubiquitinated alpha-synuclein suggesting that impaired protein clearance is an important event in aggregate formation. The A30P mutation is known for its fast oligomerization, but slow fibrillization rate. Despite its toxicity to neurons, mechanisms involved in either clearance or conversion of A30P alpha-synuclein from its soluble state into insoluble fibrils and their effects in vivo are poorly understood. Synphilin-1 is present in Lewy bodies, interacting with alpha-synuclein in vivo and in vitro and promotes its sequestration into aggresomes, which are thought to act as cytoprotective agents facilitating protein degradation. We therefore crossed animals overexpressing A30P alpha-synuclein with synphilin-1 transgenic mice to analyze its impact on aggregation, protein clearance and phenotype progression. We observed that co-expression of synphilin-1 mildly delayed the motor phenotype caused by A30P alpha-synuclein. Additionally, the presence of N- and C-terminal truncated alpha-synuclein species and fibrils were strongly reduced in double-transgenic mice when compared with single-transgenic A30P mice. Insolubility of mutant A30P and formation of aggresomes was still detectable in aged double-transgenic mice, paralleled by an increase of ubiquitinated proteins and high autophagic activity. Hence, this study supports the notion that co-expression of synphilin-1 promotes formation of autophagic-susceptible aggresomes and consecutively the degradation of human A30P alpha-synuclein. Notably, although synphilin-1 overexpression significantly reduced formation of fibrils and astrogliosis in aged animals, a similar phenotype is present in single- and double-transgenic mice suggesting additional neurotoxic processes in disease progression. PMID:24064336

  6. Genetic Analysis of the Pathogenic Molecular Sub-phenotype Interferon Alpha Identifies Multiple Novel Loci Involved in Systemic Lupus Erythematosus

    PubMed Central

    Kariuki, Silvia N.; Ghodke-Puranik, Yogita; Dorschner, Jessica M.; Chrabot, Beverly S.; Kelly, Jennifer A.; Tsao, Betty P.; Kimberly, Robert P.; Alarcón-Riquelme, Marta E.; Jacob, Chaim O.; Criswell, Lindsey A.; Sivils, Kathy L.; Langefeld, Carl D.; Harley, John B.; Skol, Andrew D.; Niewold, Timothy B.

    2014-01-01

    Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disorder characterized by inflammation of multiple organ systems and dysregulated interferon responses. SLE is both genetically and phenotypically heterogeneous, greatly reducing the power of case-control studies in SLE. Elevated circulating interferon alpha (IFN-α) is a stable, heritable trait in SLE, which has been implicated in primary disease pathogenesis. 40–50% of patients have high IFN-α, and high levels correspond with clinical differences. To study genetic heterogeneity in SLE, we performed a case-case study comparing patients with high vs. low IFN-α in over 1550 SLE cases, including GWAS and replication cohorts. In meta-analysis, the top associations in European ancestry were PRKG1 rs7897633 (PMeta=2.75 × 10−8) and PNP rs1049564 (PMeta=1.24 × 10−7). We also found evidence for cross-ancestral background associations with the ANKRD44 and PLEKHF2 loci. These loci have not been previously identified in case-control SLE genetic studies. Bioinformatic analyses implicated these loci functionally in dendritic cells and natural killer cells, both of which are involved in IFN-α production in SLE. As case-control studies of heterogeneous diseases reach a limit of feasibility with respect to subject number and detectable effect size, the study of informative pathogenic subphenotypes becomes an attractive strategy for genetic discovery in complex disease. PMID:25338677

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

    PubMed Central

    Kraus, Teresa; Cherry, Mohamad

    2014-01-01

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

  8. Test-retest reliability of cognitive EEG

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  9. Preserved functional autonomic phenotype in adult mice overexpressing moderate levels of human alpha-synuclein in oligodendrocytes.

    PubMed

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

    2014-11-01

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

  10. Fluctuations between sleep and wakefulness: wake-like features indicated by increased EEG alpha power during different sleep stages in nightmare disorder.

    PubMed

    Simor, Pter; Horvth, Klra; Ujma, Pter P; Gombos, Ferenc; Bdizs, Rbert

    2013-12-01

    Although a growing body of research indicates that frequent nightmares are related to impaired sleep regulation, the pathophysiology of nightmare disorder is far from being fully understood. We examined the relative spectral power values for NREM and REM sleep separately in 19 individuals with nightmare disorder and 21 healthy controls, based on polysomnographic recordings of the second nights' laboratory sleep. Nightmare subjects compared to controls exhibited increased relative high alpha (10-14.5Hz) and fronto-central increases in high delta (3-4Hz) power during REM sleep, and a trend of increased fronto-central low alpha (7.75-9Hz) power in NREM sleep. These differences were independent of the confounding effects of waking emotional distress. High REM alpha and low NREM alpha powers were strongly related in nightmare but not in control subjects. The topographical distribution and spectral components of REM alpha activity suggest that nightmare disordered subjects are characterized by wake-like electroencephalographic features during REM sleep. PMID:23831546

  11. Longitudinal study of EEG frequency maturation and power changes in children on the Russian North.

    PubMed

    Soroko, S I; Shemyakina, N V; Nagornova, Zh V; Bekshaev, S S

    2014-11-01

    The aim of the study was to reveal longitudinal changes in electroencephalogram spectral power and frequency (percentage frequency composition of EEG and alpha peak frequency) patterns in normal children from northern Russia. Fifteen children (9 girls and 6 boys) participated in the study. The resting state (eyes closed) EEGs were recorded yearly (2005-2013) from age 8 to age 16-17 for each child. EEG frequency patterns were estimated as the percentages of waves with a 1 Hz step revealed by measuring the interval durations between points crossing zero (isoline) by a curve. EEG spectral power changes were analyzed for delta (1.5-4 Hz), theta (4-7.5 Hz), alpha-1 (7.5-9.5 Hz), alpha-2 (9.5-12.5 Hz), beta-1 (12.5-18 Hz) and beta-2 (18-30 Hz) bands. According to the frequency composition of the EEG signals fast synchronous, polymorphous synchronous, polymorphous desynchronous and slow synchronous types of children EEG were revealed. These EEG types were relatively stable during adolescence. In these EEG types, the frequency patterns and spectral power dynamics with age had several common and specific features. Slow wave percentage and spectral power in the delta band remarkably decreased with age in all groups. Starting from the theta band the EEG types were characterized by different EEG spectral power changes with age. In fast synchronous EEG type, the theta and alpha-1 EEG power decreased, and the alpha-2 power increased in the occipital and parietal areas. The polymorphous synchronous type was characterized by increased both the alpha-1 and alpha-2 power with regional peculiarities. In the polymorphous desynchronous type spectral power in all bands decreased with age, and in the slow synchronous type, the alpha-1 power massively increased with age. Obtained results suggest predictive strength of the spatial-frequency patterns in EEG for its following maturation through the years. PMID:25219895

  12. Effects of 2G and 3G mobile phones on human alpha rhythms: Resting EEG in adolescents, young adults, and the elderly.

    PubMed

    Croft, R J; Leung, S; McKenzie, R J; Loughran, S P; Iskra, S; Hamblin, D L; Cooper, N R

    2010-09-01

    The present study was conducted to determine whether adolescents and/or the elderly are more sensitive to mobile phone (MP)-related bioeffects than young adults, and to determine this for both 2nd generation (2G) GSM, and 3rd generation (3G) W-CDMA exposures. To test this, resting alpha activity (8-12 Hz band of the electroencephalogram) was assessed because numerous studies have now reported it to be enhanced by MP exposure. Forty-one 13-15 year olds, forty-two 19-40 year olds, and twenty 55-70 year olds were tested using a double-blind crossover design, where each participant received Sham, 2G and 3G exposures, separated by at least 4 days. Alpha activity, during exposure relative to baseline, was recorded and compared between conditions. Consistent with previous research, the young adults' alpha was greater in the 2G compared to Sham condition, however, no effect was seen in the adolescent or the elderly groups, and no effect of 3G exposures was found in any group. The results provide further support for an effect of 2G exposures on resting alpha activity in young adults, but fail to support a similar enhancement in adolescents or the elderly, or in any age group as a function of 3G exposure. PMID:20564174

  13. The effects of centrally acting drugs on the EEG correlates of meditation.

    PubMed

    Sim, M K; Tsoi, W F

    1992-09-01

    The present study investigated the effects of three centrally acting drugs on the significant increase in the intermediate alpha frequency of the electroencephalogram (EEG) that accompanied meditation in a male volunteer. When compared to the EEG recorded before each of the three drugs was administered, naloxone tended to enhance the increase in the power of the intermediate alpha EEG (9.4-10.4 Hz), while diazepam tended to spread the increase to the slow (7.4-9.4 Hz) alpha EEG, and flumazenil was without much effect on the overall EEG pattern. However, these EEG changes when compared to similar changes obtained with saline administration were not significantly different from the latter. Thus, it is unlikely that the EEG correlates of meditation are causally related to the rise or fall of endogenous opioid peptides or benzodiazepinelike substances in the brain. PMID:1515478

  14. Measuring directional coupling between EEG sources.

    PubMed

    Gómez-Herrero, Germán; Atienza, Mercedes; Egiazarian, Karen; Cantero, Jose L

    2008-11-15

    Directional connectivity in the brain has been typically computed between scalp electroencephalographic (EEG) signals, neglecting the fact that correlations between scalp measurements are partly caused by electrical conduction through the head volume. Although recently proposed techniques are able to identify causality relationships between EEG sources rather than between recording sites, most of them need a priori assumptions about the cerebral regions involved in the EEG generation. We present a novel methodology based on multivariate autoregressive (MVAR) modeling and Independent Component Analysis (ICA) able to determine the temporal activation of the intracerebral EEG sources as well as their approximate locations. The direction of synaptic flow between these EEG sources is then estimated using the directed transfer function (DTF), and the significance of directional coupling strength evaluated with surrogated data. The reliability of this approach was assessed with simulations manipulating the number of data samples, the depth and orientation of the equivalent source dipoles, the presence of different noise sources, and the violation of the non-Gaussianity assumption inherent to the proposed technique. The simulations showed the superior accuracy of the proposed approach over other traditional techniques in most tested scenarios. Its validity was also evaluated analyzing the generation mechanisms of the EEG-alpha rhythm recorded from 20 volunteers under resting conditions. Results suggested that the major generation mechanism underlying EEG-alpha oscillations consists of a strong bidirectional feedback between thalamus and cuneus. The precuneus also seemed to actively participate in the generation of the alpha rhythm although it did not exert a significant causal influence neither on the thalamus nor on the cuneus. All together, these results suggest that the proposed methodology is a promising non-invasive approach for studying directional coupling between mutually interconnected neural populations. PMID:18707006

  15. The Mozart Effect: A quantitative EEG study.

    PubMed

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

    2015-09-01

    The aim of this study is to investigate the influence of Mozart's music on brain activity through spectral analysis of the EEG in young healthy adults (Adults), in healthy elderly (Elderly) and in elderly with Mild Cognitive Impairment (MCI). EEG recording was performed at basal rest conditions and after listening to Mozart's K448 or "Fur Elise" Beethoven's sonatas. After listening to Mozart, an increase of alpha band and median frequency index of background alpha rhythm activity (a pattern of brain wave activity linked to memory, cognition and open mind to problem solving) was observed both in Adults and in Elderly. No changes were observed in MCI. After listening to Beethoven, no changes in EEG activity were detected. This results may be representative of the fact that said Mozart's music is able to "activate" neuronal cortical circuits related to attentive and cognitive functions. PMID:26036835

  16. EEG findings in fetal alcohol syndrome and Down syndrome children.

    PubMed

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

    1996-01-01

    Results from previous studies evaluating the electroencephalograms (EEGs) of infants born to alcoholic mothers suggest that the neonatal EEG may be a sensitive measure of prenatal ethanol exposure. Few studies, however, have examined EEG records of adolescent children with fetal alcohol syndrome (FAS). The present study investigated the resting EEG recordings of 18 matched triads of FAS, Down syndrome, and normal control subjects. Significant reductions in mean power of the alpha frequencies (7.5-12 Hz) were seen for both clinical groups, however, each syndrome appeared to have distinct EEG spectral distributions. Down syndrome children overall had diffuse EEG slowing while the EEG records of the FAS children showed reduced power, particularly in the alpha frequencies in the absence of significant slow activity. In the Down syndrome children, significant decreases in alpha power was seen in posterior cortical regions, whereas FAS children were more affected in the left hemisphere. This study suggests that certain EEG variables may be helpful in characterizing the neurophysiology of FAS. PMID:8689990

  17. Human EEG spectra before and during cannabis hallucinations.

    PubMed

    Koukkou, M; Lehmann, D

    1976-12-01

    EEG correlates of subjective experiences induced by delta9-trans-tetrahydrocannabinol (THC) and EEG correlates of individual disposition to such experiences were investigated. Twelve normal volunteers took 200 mug/kg THC orally. The subjects were asked to signal subjective experiences. The EEG was analyzed (period analysis) before and repeatedly after THC injestion, during resting, attention, eye closure, visual hallucinations, and body image disturbances. EEG frequency spectra differed significantly between resting and visual hallucinations and body image disturbances. The differences included slower alpha and more theta during THC experiences, reminiscent of initial drowsiness EEG, and of some results in schizophrenia. The differences between spectra during visual hallucinations and during body image disturbances indicate different functional brain states. Subjects with a high tendency to cannabinol induced experiences exhibited resting spectra before and after THC with higher modal alpha frequences (reminiscent of subjects with high neuroticism scores) than subjects with a low tendency. PMID:999986

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

    PubMed

    Itil, T M

    1978-03-01

    The results of the qualitative but particularly the quantitative EEG-studies indicate that 1. The EEG of adult schizophrenics is characterized by an appearance of excessive fast activity along with some slow waves and the lack of alpha-activity. 2. Excessive fast activity and lack of alpha-waves have also been found in the EEGs of psychotic children and most interestingly in children whose parents (particularly the mother) are schizophrenic (high risk children). 3. Based on the studies during sleep and investigations with neuroleptics, it was established that the origin of the excess fast activity in schizophrenia cannot be the muscle potential. Particularly the excess fast activity in high risk children for schizophrenia goes against the muscle potential hypothesis. 4. The quantitative EEG changes seen in schizophrenia show similarity to those seen after hallucinogenic compounds particularly after anticholinergic hallucinogenics. 5. All neuroleptics (major tranquilizers) produce quantitative EEG alterations which are almost diametrically opposite to those seen in schizoprenia. PMID:416942

  19. Quantitative EEG analysis in post-traumatic anosmia.

    PubMed

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

    2006-12-11

    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

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

    PubMed Central

    Saby, Joni N.; Marshall, Peter J.

    2012-01-01

    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. PMID:22545661

  1. [EEG monitoring of epilepsy].

    PubMed

    Peleteiro Fernández, M

    1999-05-01

    Electroencephalography (EEG) constitutes an integral part of the diagnostic process in epilepsy. It is the most important method of investigation in the management of epilepsy and has been widely developed in the last few decades. At present, technological development has provided us with the digital EEG and miniaturization of the equipment with which we are able to register as many channels as necessary in any circumstance and for an indefinite period of time, and together with the development of information technology we are now able to obtain rapid and effective analysis of large amounts of data and a reduction in the number of apparatus. These changes have revolutionized EEG. The EEG which has been used as a diagnostic procedure a posteriori, has increasing application in the direct monitoring of cerebral function. Prolonged EEG monitoring or that performed in the ambulatory, in intensive care units and the video EEG are increasingly accessible and necessary tools for the management of epilepsy. PMID:10379161

  2. Modeling and detecting deep brain activity with MEG & EEG.

    PubMed

    Attal, Yohan; Bhattacharjee, Manik; Yelnik, Jerome; Cottereau, Benoit; Lefèvre, Julien; Okada, Yoshio; Bardinet, Eric; Chupin, Marie; Baillet, Sylvain

    2007-01-01

    We introduce an anatomical and electrophysiological model of deep brain structures dedicated to magnetoencephalography (MEG) and electroencephalography (EEG) source imaging. So far, most imaging inverse models considered that MEG/EEG surface signals were predominantly produced by cortical, hence superficial, neural currents. Here we question whether crucial deep brain structures such as the basal ganglia and the hippocampus may also contribute to distant, scalp MEG and EEG measurements. We first design a realistic anatomical and electrophysiological model of these structures and subsequently run Monte-Carlo experiments to evaluate the respective sensitivity of the MEG and EEG to signals from deeper origins. Results indicate that MEG/EEG may indeed localize these deeper generators, which is confirmed here from experimental MEG data reporting on the modulation of alpha brain waves. PMID:18003114

  3. Resting state EEG correlates of memory consolidation.

    PubMed

    Brokaw, Kate; Tishler, Ward; Manceor, Stephanie; Hamilton, Kelly; Gaulden, Andrew; Parr, Elaine; Wamsley, Erin J

    2016-04-01

    Numerous studies demonstrate that post-training sleep benefits human memory. At the same time, emerging data suggest that other resting states may similarly facilitate consolidation. In order to identify the conditions under which non-sleep resting states benefit memory, we conducted an EEG (electroencephalographic) study of verbal memory retention across 15min of eyes-closed rest. Participants (n=26) listened to a short story and then either rested with their eyes closed, or else completed a distractor task for 15min. A delayed recall test was administered immediately following the rest period. We found, first, that quiet rest enhanced memory for the short story. Improved memory was associated with a particular EEG signature of increased slow oscillatory activity (<1Hz), in concert with reduced alpha (8-12Hz) activity. Mindwandering during the retention interval was also associated with improved memory. These observations suggest that a short period of quiet rest can facilitate memory, and that this may occur via an active process of consolidation supported by slow oscillatory EEG activity and characterized by decreased attention to the external environment. Slow oscillatory EEG rhythms are proposed to facilitate memory consolidation during sleep by promoting hippocampal-cortical communication. Our findings suggest that EEG slow oscillations could play a significant role in memory consolidation during other resting states as well. PMID:26802698

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

    PubMed

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

    2016-03-01

    Spectral power (SP) of EEG alpha and beta-2 frequencies in different cortical areas has been used for neurofeedback training to control a graphic interface in different scenarios. The results show that frequency range and brain cortical areas are associated with high or low efficiency of voluntary control. Overall, EEG phenomena observed in the course of training are largely general changes involving extensive brain areas and frequency bands. Finally, we have demonstrated EEG patterns that dynamically switch with a specific feature in different tasks within one training, after a relatively short period of training. PMID:26912214

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

    PubMed

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

    2015-01-01

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

  6. An EEG-Based Fatigue Detection and Mitigation System.

    PubMed

    Huang, Kuan-Chih; Huang, Teng-Yi; Chuang, Chun-Hsiang; King, Jung-Tai; Wang, Yu-Kai; Lin, Chin-Teng; Jung, Tzyy-Ping

    2016-06-01

    Research has indicated that fatigue is a critical factor in cognitive lapses because it negatively affects an individual's internal state, which is then manifested physiologically. This study explores neurophysiological changes, measured by electroencephalogram (EEG), due to fatigue. This study further demonstrates the feasibility of an online closed-loop EEG-based fatigue detection and mitigation system that detects physiological change and can thereby prevent fatigue-related cognitive lapses. More importantly, this work compares the efficacy of fatigue detection and mitigation between the EEG-based and a nonEEG-based random method. Twelve healthy subjects participated in a sustained-attention driving experiment. Each participant's EEG signal was monitored continuously and a warning was delivered in real-time to participants once the EEG signature of fatigue was detected. Study results indicate suppression of the alpha- and theta-power of an occipital component and improved behavioral performance following a warning signal; these findings are in line with those in previous studies. However, study results also showed reduced warning efficacy (i.e. increased response times (RTs) to lane deviations) accompanied by increased alpha-power due to the fluctuation of warnings over time. Furthermore, a comparison of EEG-based and nonEEG-based random approaches clearly demonstrated the necessity of adaptive fatigue-mitigation systems, based on a subject's cognitive level, to deliver warnings. Analytical results clearly demonstrate and validate the efficacy of this online closed-loop EEG-based fatigue detection and mitigation mechanism to identify cognitive lapses that may lead to catastrophic incidents in countless operational environments. PMID:27121994

  7. Identifying periods of drowsy driving using EEG.

    PubMed

    Brown, Timothy; Johnson, Robin; Milavetz, Gary

    2013-01-01

    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

  8. Widespread EEG Changes Precede Focal Seizures

    PubMed Central

    Perucca, Piero; Dubeau, François; Gotman, Jean

    2013-01-01

    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. PMID:24260523

  9. Sleep EEG Fingerprints Reveal Accelerated Thalamocortical Oscillatory Dynamics in Williams Syndrome

    ERIC Educational Resources Information Center

    Bodizs, Robert; Gombos, Ferenc; Kovacs, Ilona

    2012-01-01

    Sleep EEG alterations are emerging features of several developmental disabilities, but detailed quantitative EEG data on the sleep phenotype of patients with Williams syndrome (WS, 7q11.23 microdeletion) is still lacking. Based on laboratory (Study I) and home sleep records (Study II) here we report WS-related features of the patterns of…

  10. Sleep EEG Fingerprints Reveal Accelerated Thalamocortical Oscillatory Dynamics in Williams Syndrome

    ERIC Educational Resources Information Center

    Bodizs, Robert; Gombos, Ferenc; Kovacs, Ilona

    2012-01-01

    Sleep EEG alterations are emerging features of several developmental disabilities, but detailed quantitative EEG data on the sleep phenotype of patients with Williams syndrome (WS, 7q11.23 microdeletion) is still lacking. Based on laboratory (Study I) and home sleep records (Study II) here we report WS-related features of the patterns of

  11. Melatonin for sleep EEG.

    PubMed

    Milstein, V; Small, J G; Spencer, D W

    1998-01-01

    Melatonin 3 mg and secobarbital 100 mg assigned randomly were given to 40 psychiatric patients for sleep induction during EEG recording. Nine patients who did sleep naturally comprised a comparison group. EEGs were read blind; most were interpreted as mildly abnormal or within normal limits. No statistically significant differences between the three groups were observed in response to photic stimulation, hyperventilation or in frequency of paroxysmal variants. The electroencephalographer was able to identify the melatonin patients significantly more accurately than those who received secobarbital on the basis of lack of EEG manifestations of fast frequencies typical of barbiturate effects. Self-assessments of drowsiness, anxiety and performance on a perceptual-motor task were similar in the melatonin and secobarbital patients. However, the secobarbital group showed more impairment on a locomotion test than those who received melatonin or slept spontaneously. The results suggest that melatonin is a plausible alternative for EEG sleep sedation, especially for ambulatory patients. PMID:9472426

  12. EEG correlates of social interaction at distance

    PubMed Central

    Giroldini, William; Pederzoli, Luciano; Bilucaglia, Marco; Caini, Patrizio; Ferrini, Alessandro; Melloni, Simone; Prati, Elena; Tressoldi, Patrizio

    2016-01-01

    This study investigated EEG correlates of social interaction at distance between twenty-five pairs of participants who were not connected by any traditional channels of communication. Each session involved the application of 128 stimulations separated by intervals of random duration ranging from 4 to 6 seconds. One of the pair received a one-second stimulation from a light signal produced by an arrangement of red LEDs, and a simultaneous 500 Hz sinusoidal audio signal of the same length. The other member of the pair sat in an isolated sound-proof room, such that any sensory interaction between the pair was impossible. An analysis of the Event-Related Potentials associated with sensory stimulation using traditional averaging methods showed a distinct peak at approximately 300 ms, but only in the EEG activity of subjects who were directly stimulated. However, when a new algorithm was applied to the EEG activity based on the correlation between signals from all active electrodes, a weak but robust response was also detected in the EEG activity of the passive member of the pair, particularly within 9 – 10 Hz in the Alpha range. Using the Bootstrap method and the Monte Carlo emulation, this signal was found to be statistically significant. PMID:26966513

  13. EEG correlates of social interaction at distance.

    PubMed

    Giroldini, William; Pederzoli, Luciano; Bilucaglia, Marco; Caini, Patrizio; Ferrini, Alessandro; Melloni, Simone; Prati, Elena; Tressoldi, Patrizio

    2015-01-01

    This study investigated EEG correlates of social interaction at distance between twenty-five pairs of participants who were not connected by any traditional channels of communication. Each session involved the application of 128 stimulations separated by intervals of random duration ranging from 4 to 6 seconds. One of the pair received a one-second stimulation from a light signal produced by an arrangement of red LEDs, and a simultaneous 500 Hz sinusoidal audio signal of the same length. The other member of the pair sat in an isolated sound-proof room, such that any sensory interaction between the pair was impossible. An analysis of the Event-Related Potentials associated with sensory stimulation using traditional averaging methods showed a distinct peak at approximately 300 ms, but only in the EEG activity of subjects who were directly stimulated. However, when a new algorithm was applied to the EEG activity based on the correlation between signals from all active electrodes, a weak but robust response was also detected in the EEG activity of the passive member of the pair, particularly within 9 - 10 Hz in the Alpha range. Using the Bootstrap method and the Monte Carlo emulation, this signal was found to be statistically significant. PMID:26966513

  14. [The EEG and thinking].

    PubMed

    Petsche, H

    1990-12-01

    The on-going EEG contains information on thinking strategies during cognitive and creative tasks and during listening to music. This was demonstrated by a method taking use of the fact that both the amount of local current production and the degree of electric coupling of brain regions is characteristically changed by mental tasks. In groups of volunteers the significant changes of absolute power and coherence caused by different mental tasks are computed and entered into schematic brain maps (EEG probability maps). The results indicate the existence of general brain strategies even in mental activities as specific as those referred to above. Moreover, several relationships between EEG, psychological test scores, degree of special education and intelligence were found. Studies with extreme value validation according to intelligence and creativity test scores yielded significant differences between the groups of the best and the poorest performers during a creative task in the EEG. The EEG thus can be conceived of as deterministic chaos with different degrees of organization according to its information content. In this context, the question arises as to a possible function of the EEG for the optimization of thinking processes. PMID:2127009

  15. EEG correlates of emotions in dream narratives from typical young adults and individuals with autistic spectrum disorders.

    PubMed

    Daoust, Anne-Marie; Lusignan, Félix-Antoine; Braun, Claude M J; Mottron, Laurent; Godbout, Roger

    2008-03-01

    The relationship between emotional dream content and Alpha and Beta REM sleep EEG activity was investigated in typical individuals and in Autistic Spectrum Disorders (ASD). Dream narratives of persons with ASD contained fewer emotional elements. In both groups, emotions correlated positively with slow Alpha (8.0-10.0 Hz) spectral power over parieto-occipital and left central regions, as well as with a right occipital EEG asymmetry. Slow Alpha activity in ASD individuals was lower over midline and parasagittal areas and higher over lateral areas compared to controls. Both groups displayed a right-biased slow Alpha activity for midparietal and occipital (significantly higher in control) sites. Results indicate that Alpha EEG activity may represent a neurophysiological substrate associated with emotional dream content. Distinctive Alpha EEG patterns and asymmetries suggest that dream generation implies different brain connectivity in ASD. PMID:18047484

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

    PubMed Central

    Stevens, J R; Livermore, A

    1982-01-01

    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 PMID:7086451

  17. Hypermethods for EEG hyperscanning.

    PubMed

    Babiloni, Fabio; Cincotti, Febo; Mattia, Donatella; Mattiocco, Marco; De Vico Fallani, Fabrizio; Tocci, Andrea; Bianchi, Luigi; Marciani, Maria Grazia; Astolfi, Laura

    2006-01-01

    Until now, in EEG studies the activity of the brain during simple or complex tasks have been recorded in a single subject. Often, during such EEG recordings, subjects interacts with the external devices or the researchers in order to reproduce conditions similar to the those usually occurring in the real-life. However, in order to study the concurrent activity in subjects interacting in cooperation or competition activities, the issue of the simultaneous recording of their brain activity became mandatory. The simultaneous recording of hemodynamic or neuroelectric activity of the brain is called "hyperscanning". We would like present results obtained by EEG hyperscannings performed on a group of subjects engaged in cooperative games. The EEG hyperscannings have been performed with the simultaneous use of high resolution EEG devices on groups of three and four subjects while they were playing cooperative games. The analysis of such data have been conducted with analysis method that taken into account the particular nature of the data simultaneously gathered from different subjects. We called these methods hypermethods. In particular, we estimate the concurrent activity in multiple brains of the group and we depicted the causal connections between regions of different brains (hyperconnectivity). The resulting causality patterns will link certain areas of the brain of a subject to the waveforms obtained from the other brain areas of another subject of the same group. Results obtained in a study of several groups recorded by the hyperscanning reveals causal links between prefrontal areas of the different subjects when they are performing cooperative games in different frequency bands. Hypermethods for hyperscanning will open a different area for the study of neuroscience, in which the activity of multiple brains during social cooperation could be investigated. In such area the importance of EEG will be relevant due to its temporal and spatial resolution now obtainable w- ith the high resolution EEG techniques. PMID:17945788

  18. [EEG synchronisation in autistic children. Analysis of coherency].

    PubMed

    Luschekina, E A; Haerdinova, O Yu; Novototsky-Vlasov, V Yu; Luschekin, V S; Strelets, V B

    2015-01-01

    EEG study of 5-7 years boys with autism revealed lower values of coherence in background delta, theta and alpha bands and higher values of coherence in background beta 1, beta 2 and gamma bands. Healthy boys showed higher values of beta and gamma coherence during cognitive task. Autistic persons demonstrated higher values of theta coherence during cognitive task. PMID:25966574

  19. Invasive EEG explorations.

    PubMed

    Taussig, D; Montavont, A; Isnard, J

    2015-03-01

    The Wada test was adapted from the procedure described by Wada in 1964. It still has a role in the prognostic evaluation of memory disorders after mesial temporal lobectomy. The test consists of injecting a short-acting anesthetic into one hemisphere, under continuous EEG monitoring and during carotid catheterization, to verify the function of contralateral structures. Intracranial EEG recordings deliver signals with few artifacts, and which are quite specific of the zone explored. Three types of electrodes are in common use: (a) foramen ovale (FO) electrodes: electrodes can be inserted directly, without any stereotactic procedure, to provide easy and comparative EEG recordings of the lower and middle portions of the temporal lobe close to the hippocampus. These allow validation of the temporal lobe origin of seizures using FO electrodes recording coupled with scalp EEG; (b): subdural strip or grip electrodes. This relatively aggressive technique carries infectious and hemorrhagic risks and does not allow the exploration of deep cortical structures. However, it permits precise functional cortical mapping via electrical stimulation because of dense and regular positioning of electrodes over the cortical convexity; (c) stereotactically implanted depth electrodes (stereo-electroencephalography [SEEG]). Electrodes are individually planned and inserted within the brain parenchyma through small burr holes. This technique is less aggressive than subdural grid exploration. However it offers relatively limited spatial sampling that may be less well adapted to precise functional evaluation. It allows recording from deep cortical structures and can be argued to be the gold standard of presurgical EEG exploration. PMID:25703438

  20. [Age Effect on Relationship Between Intelligence and EEG Characteristics].

    PubMed

    Belousova, L V; Razumnikova, O M; Volf, N V

    2015-01-01

    Age effect on EEG correlates of psychometrically estimated intelligence (IQ) in the younger (N = 132, age mean = 21.8 ± 3.1) and elder groups (N = 84, age mean = 64.1 ± 6.6) was studied. Regression analysis of individual alpha peak frequency's meanings, total power of biopotentials in eight frequency ranges indicated that a decrease of IQ correlates with age increase, or with decrease of individual alpha peak frequency with positive contribution of the alpha3 power and negative--of the beta1. High meaning of the alpha3 power and low meaning of the beta1 are the predictors of high intelligence in the younger group. High intelligence in the elder group is accompanied by a trend to increase of the individual alpha peak frequency and to decrease of the theta/beta1 power ration together with significant decrease of the alpha3/alpha2 power ratio. PMID:26841657

  1. Hypnagogic imagery and EEG activity.

    PubMed

    Hayashi, M; Katoh, K; Hori, T

    1999-04-01

    The relationships between hypnagogic imagery and EEG activity were studied. 7 subjects (4 women and 3 men) reported the content of hypnagogic imagery every minute and the hypnagogic EEGs were classified into 5 stages according to Hori's modified criteria. The content of the hypnagogic imagery changed as a function of the hypnagogic EEG stages. PMID:10483662

  2. EEG activity during the performance of complex mental problems.

    PubMed

    Jausovec, N; Jausovec, K

    2000-04-01

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

  3. Flexible electroencephalogram (EEG) headband

    NASA Technical Reports Server (NTRS)

    Raggio, L. J.

    1973-01-01

    Headband incorporates sensors which are embedded in sponges and are exposed only on surface that touches skin. Electrode sponge system is continually fed electrolyte through forced feed vacuum system. Headband may be used for EEG testing in hospitals, clinical laboratories, rest homes, and law enforcement agencies.

  4. EEG data compression techniques.

    PubMed

    Antoniol, G; Tonella, P

    1997-02-01

    In this paper, electroencephalograph (EEG) and Holter EEG data compression techniques which allow perfect reconstruction of the recorded waveform from the compressed one are presented and discussed. Data compression permits one to achieve significant reduction in the space required to store signals and in transmission time. The Huffman coding technique in conjunction with derivative computation reaches high compression ratios (on average 49% on Holter and 58% on EEG signals) with low computational complexity. By exploiting this result a simple and fast encoder/decoder scheme capable of real-time performance on a PC was implemented. This simple technique is compared with other predictive transformations, vector quantization, discrete cosine transform (DCT), and repetition count compression methods. Finally, it is shown that the adoption of a collapsed Huffman tree for the encoding/decoding operations allows one to choose the maximum codeword length without significantly affecting the compression ratio. Therefore, low cost commercial microcontrollers and storage devices can be effectively used to store long Holter EEG's in a compressed format. PMID:9214790

  5. Functional phenotype of phosphoinositide 3-kinase p85alpha-null platelets characterized by an impaired response to GP VI stimulation.

    PubMed

    Watanabe, Naohide; Nakajima, Hideaki; Suzuki, Hidenori; Oda, Atsushi; Matsubara, Yumiko; Moroi, Masaaki; Terauchi, Yasuo; Kadowaki, Takashi; Suzuki, Harumi; Koyasu, Shigeo; Ikeda, Yasuo; Handa, Makoto

    2003-07-15

    Phosphoinositide 3-kinases (PI3Ks), a family of lipid kinases comprising 3 classes with multiple isoforms, have been shown to participate in different phases of platelet signaling. To investigate the roles that enzymes play in platelet function in vivo and determine which isoforms are important for particular signaling events, we analyzed platelet function of gene knockout mice deficient in the p85alpha regulatory subunit of heterodimeric class IA PI3K. The kinase activity of p85alpha-/- platelets was only 5% of the activity of platelets from wild-type littermates. Platelet aggregation induced by adenosine diphosphate (ADP), thrombin, U46619, phorbol 12-myristate 13-acetate (PMA), or botrocetin was not defective in p85alpha-/- mice, compared with wild-type animals. In contrast, aggregation induced by collagen and collagen-related peptide (CRP) was partially but readily impaired in p85alpha-/- mice. Both P-selectin expression and fibrinogen binding in response to CRP were also decreased to a similar extent in p85alpha-/- platelets. Platelets from p85alpha-/- mice appeared to spread poorly over a CRP-coated surface with intact filopodial protrusions. Significant attenuation of CRP-induced tyrosine phosphorylation in known PI3K effectors such as Btk, Tec, PKB/Akt, and phospholipase Cgamma2 were observed with p85alpha-/- platelets, whereas no alteration was noted in upstream molecules of Syk, LAT, and SLP-76. Considered as a whole, these results provide the first genetic evidence that PI3K p85alpha plays a significant role in platelet function, almost exclusively in the glycoprotein (GP) VI/Fc receptor gamma chain complex-mediated signaling pathway. PMID:12649157

  6. Motion and ballistocardiogram artifact removal for interleaved recording of EEG and EPs during MRI.

    PubMed

    Bonmassar, Giorgio; Purdon, Patrick L; Jääskeläinen, Iiro P; Chiappa, Keith; Solo, Victor; Brown, Emery N; Belliveau, John W

    2002-08-01

    Artifacts generated by motion (e.g., ballistocardiac) of the head inside a high magnetic field corrupt recordings of EEG and EPs. This paper introduces a method for motion artifact cancellation. This method is based on adaptive filtering and takes advantage of piezoelectric motion sensor information to estimate the motion artifact noise. This filter estimates the mapping between motion sensor and EEG space, subtracting the motion-related noise from the raw EEG signal. Due to possible subject motion and changes in electrode impedance, a time-varying mapping of the motion versus EEG is required. We show that this filter is capable of removing both ballistocardiogram and gross motion artifacts, restoring EEG alpha waves (8-13 Hz), and visual evoked potentials (VEPs). This adaptive filter outperforms the simple band-pass filter for alpha detection because it is also capable of reducing noise within the frequency band of interest. In addition, this filter also removes the transient responses normally visible in the EEG window after echo planar image acquisition, observed during interleaved EEG/fMRI recordings. Our adaptive filter approach can be implemented in real-time to allow for continuous monitoring of EEG and fMRI during clinical and cognitive studies. PMID:12202099

  7. EEG INDICES OF TONIC PAIN-RELATED ACTIVITY IN THE SOMATOSENSORY CORTICES

    PubMed Central

    Dowman, Robert; Rissacher, Daniel; Schuckers, Stephanie

    2009-01-01

    Objective To identify EEG features that index pain-related cortical activity, and to identify factors that can mask the pain-related EEG features and/or produce features that can be misinterpreted as pain-specific. Methods The EEG was recorded during 3 conditions presented in counterbalanced order: a tonic cold pain condition, and pain anticipation and arithmetic control conditions. The EEG was also recorded while the subjects made a wincing facial expression to estimate the contribution of scalp EMG artifacts to the pain-related EEG features. Results Alpha amplitudes decreased over the contralateral temporal scalp and increased over the posterior scalp during the cold pain condition. There was an increase in gamma band activity during the cold pain condition at most electrode locations that was due to EMG artifacts. Conclusions The decrease in alpha over the contralateral temporal scalp during cold pain is consistent with pain-related activity in the primary somatosensory cortex and/or the somatosensory association areas located in the parietal operculum and/or insula. This study also identified factors that might mask the pain-related EEG features and/or generate EEG features that could be misinterpreted as being pain-specific. These include (but are not limited to) an increase in alpha generated in the visual cortex that results from attention being drawn towards the pain; the widespread increase in gamma band activity that results from scalp EMG generated by the facial expressions that often accompany pain; and the possibility that non-specific changes in the EEG over time mask the pain-related EEG features when the pain and control conditions are given in the same order across subjects. Significance This study identified several factors that need to be controlled and/or isolated in order to successfully record EEG features that index pain-related activity in the somatosensory cortices. PMID:18337168

  8. Atypical Alpha Asymmetry in Adults with ADHD

    ERIC Educational Resources Information Center

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

    2009-01-01

    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…

  9. Association of EEG, MRI, and regional blood flow biomarkers is predictive of prodromal Alzheimer’s disease

    PubMed Central

    Moretti, Davide Vito

    2015-01-01

    Background Thinning in the temporoparietal cortex, hippocampal atrophy, and a lower regional blood perfusion is connected with prodromal stage of Alzheimer’s disease (AD). Of note, an increase of electroencephalography (EEG) upper/low alpha frequency power ratio has also been associated with these major landmarks of prodromal AD. Methods Clinical and neuropsychological assessment, EEG recording, and high-resolution three-dimensional magnetic resonance imaging were done in 74 grown up subjects with mild cognitive impairment. This information was gathered and has been assessed 3 years postliminary. EEG recording and perfusion single-photon emission computed tomography assessment was done in 27 subjects. Alpha3/alpha2 frequency power ratio, including cortical thickness, was figured for every subject. Contrasts in cortical thickness among the groups were assessed. Pearson’s r relationship coefficient was utilized to evaluate the quality of the relationship between cortical thinning, brain perfusion, and EEG markers. Results The higher alpha3/alpha2 frequency power ratio group corresponded with more prominent cortical decay and a lower perfusional rate in the temporoparietal cortex. In a subsequent meetup after 3 years, these patients had AD. Conclusion High EEG upper/low alpha power ratio was connected with cortical diminishing and lower perfusion in the temporoparietal brain area. The increase in EEG upper/low alpha frequency power ratio could be helpful in recognizing people in danger of conversion to AD dementia and this may be quality information in connection with clinical assessment. PMID:26604762

  10. How to use: amplitude-integrated EEG (aEEG).

    PubMed

    Shah, Nidhi Agrawal; Wusthoff, Courtney Jane

    2015-04-01

    Amplitude-integrated electroencephalography (aEEG) is a method for continuous monitoring of brain activity that is increasingly used in the neonatal intensive care unit. In its simplest form, aEEG is a processed single-channel electroencephalogram that is filtered and time-compressed. Current evidence demonstrates that aEEG is useful to monitor cerebral background activity, diagnose and treat seizures and predict neurodevelopmental outcomes for preterm and term infants. This review aims to explain the fundamentals behind aEEG and its clinical applications. PMID:25035312

  11. EEG analyses with SOBI.

    SciTech Connect

    Glickman, Matthew R.; Tang, Akaysha

    2009-02-01

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

  12. Electroencephalograph (EEG) study of brain bistable illusion

    NASA Astrophysics Data System (ADS)

    Meng, Qinglei; Hong, Elliot; Choa, Fow-Sen

    2015-05-01

    Bistable illusion reflects two different kinds of interpretations for a single image, which is currently known as a competition between two groups of antagonism of neurons. Recent research indicates that these two groups of antagonism of neurons express different comprehension, while one group is emitting a pulse, the other group will be restrained. On the other hand, when this inhibition mechanism becomes weaker, the other antagonism neurons group will take over the interpretation. Since attention plays key roles controlling cognition, is highly interesting to find the location and frequency band used by brain (with either top-down or bottom-up control) to reach deterministic visual perceptions. In our study, we used a 16-channel EEG system to record brain signals from subjects while conducting bistable illusion testing. An extra channel of the EEG system was used for temporal marking. The moment when subjects reach a perception switch, they click the channel and mark the time. The recorded data were presented in form of brain electrical activity map (BEAM) with different frequency bands for analysis. It was found that the visual cortex in the on the right side between parietal and occipital areas was controlling the switching of perception. In the periods with stable perception, we can constantly observe all the delta, theta, alpha and beta waves. While the period perception is switching, almost all theta, alpha, and beta waves were suppressed by delta waves. This result suggests that delta wave may control the processing of perception switching.

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

    SciTech Connect

    Steinlein, O.; Weiland, S.; Stoodt, J.; Propping, P.

    1996-03-01

    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.

  14. Effects of tobacco smoking on the topographic EEG II.

    PubMed

    Domino, E F; Riskalla, M; Zhang, Y; Kim, E

    1992-07-01

    1. Tobacco smokers are well aware of the long term hazards of tobacco smoking, yet they continue to smoke. Presumably people smoke because of short term gains due to nicotine. 2. The mechanism by which nicotine is a drug reinforcer still needs a great deal of study. The specific aim of the present study was to determine the effects of tobacco smoking on the topographic EEG of 12 hr deprived heavy tobacco smokers. 3. Seven normal adult tobacco smokers of mixed sex were recruited into the study and compared with six normal nonsmokers of similar age and sex. 4. A Grass Model 8-24D EEG and 16 different scalp monopolar electrodes were used to record the EEG using both ears as reference before and after smoking. EKG lead II was recorded on channel 17. Blood pressure was measured by auscultation. Exhaled CO was measured using a CO detector. Computer analysis of the EEG data was run of line on a Zenith 386/25 microcomputer using RHYTHM 7.1. The same system was used to store the EEG in digitized form. The maximum number of 4 sec artifact free epochs in a 3 min recording period with eyes open and then closed was used before and after low and high nicotine tobacco or sham smoking. 5. The hypothesis of this research was confirmed, i.e., that tobacco smoking of high nicotine cigarettes (about 2.0 mg/cigarette) would cause a shift in EEG alpha rhythm to higher frequencies in more diffuse midline cortical structures. In other studies an increase in alpha rhythm has been correlated with an awake relaxed behavioral state. 6. A heart rate increase was a more sensitive index of tobacco smoking than an increase in arterial blood pressure. Exhaled smoking CO levels correlated with the nicotine and tar content of the cigarette. PMID:1641492

  15. Model driven EEG/fMRI fusion of brain oscillations.

    PubMed

    Valdes-Sosa, Pedro A; Sanchez-Bornot, Jose Miguel; Sotero, Roberto Carlos; Iturria-Medina, Yasser; Aleman-Gomez, Yasser; Bosch-Bayard, Jorge; Carbonell, Felix; Ozaki, Tohru

    2009-09-01

    This article reviews progress and challenges in model driven EEG/fMRI fusion with a focus on brain oscillations. Fusion is the combination of both imaging modalities based on a cascade of forward models from ensemble of post-synaptic potentials (ePSP) to net primary current densities (nPCD) to EEG; and from ePSP to vasomotor feed forward signal (VFFSS) to BOLD. In absence of a model, data driven fusion creates maps of correlations between EEG and BOLD or between estimates of nPCD and VFFS. A consistent finding has been that of positive correlations between EEG alpha power and BOLD in both frontal cortices and thalamus and of negative ones for the occipital region. For model driven fusion we formulate a neural mass EEG/fMRI model coupled to a metabolic hemodynamic model. For exploratory simulations we show that the Local Linearization (LL) method for integrating stochastic differential equations is appropriate for highly nonlinear dynamics. It has been successfully applied to small and medium sized networks, reproducing the described EEG/BOLD correlations. A new LL-algebraic method allows simulations with hundreds of thousands of neural populations, with connectivities and conduction delays estimated from diffusion weighted MRI. For parameter and state estimation, Kalman filtering combined with the LL method estimates the innovations or prediction errors. From these the likelihood of models given data are obtained. The LL-innovation estimation method has been already applied to small and medium scale models. With improved Bayesian computations the practical estimation of very large scale EEG/fMRI models shall soon be possible. PMID:19107753

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

    PubMed

    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

    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 κf 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 kΩ (SD: 31.9 kΩ). 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

  17. Brain Oscillations in Sport: Toward EEG Biomarkers of Performance.

    PubMed

    Cheron, Guy; Petit, Géraldine; Cheron, Julian; Leroy, Axelle; Cebolla, Anita; Cevallos, Carlos; Petieau, Mathieu; Hoellinger, Thomas; Zarka, David; Clarinval, Anne-Marie; Dan, Bernard

    2016-01-01

    Brain dynamics is at the basis of top performance accomplishment in sports. The search for neural biomarkers of performance remains a challenge in movement science and sport psychology. The non-invasive nature of high-density electroencephalography (EEG) recording has made it a most promising avenue for providing quantitative feedback to practitioners and coaches. Here, we review the current relevance of the main types of EEG oscillations in order to trace a perspective for future practical applications of EEG and event-related potentials (ERP) in sport. In this context, the hypotheses of unified brain rhythms and continuity between wake and sleep states should provide a functional template for EEG biomarkers in sport. The oscillations in the thalamo-cortical and hippocampal circuitry including the physiology of the place cells and the grid cells provide a frame of reference for the analysis of delta, theta, beta, alpha (incl.mu), and gamma oscillations recorded in the space field of human performance. Based on recent neuronal models facilitating the distinction between the different dynamic regimes (selective gating and binding) in these different oscillations we suggest an integrated approach articulating together the classical biomechanical factors (3D movements and EMG) and the high-density EEG and ERP signals to allow finer mathematical analysis to optimize sport performance, such as microstates, coherency/directionality analysis and neural generators. PMID:26955362

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

    NASA Astrophysics Data System (ADS)

    Teplan, Michal; Krakovská, Anna; Špajdel, Marián

    2014-08-01

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

  19. Brain Oscillations in Sport: Toward EEG Biomarkers of Performance

    PubMed Central

    Cheron, Guy; Petit, Géraldine; Cheron, Julian; Leroy, Axelle; Cebolla, Anita; Cevallos, Carlos; Petieau, Mathieu; Hoellinger, Thomas; Zarka, David; Clarinval, Anne-Marie; Dan, Bernard

    2016-01-01

    Brain dynamics is at the basis of top performance accomplishment in sports. The search for neural biomarkers of performance remains a challenge in movement science and sport psychology. The non-invasive nature of high-density electroencephalography (EEG) recording has made it a most promising avenue for providing quantitative feedback to practitioners and coaches. Here, we review the current relevance of the main types of EEG oscillations in order to trace a perspective for future practical applications of EEG and event-related potentials (ERP) in sport. In this context, the hypotheses of unified brain rhythms and continuity between wake and sleep states should provide a functional template for EEG biomarkers in sport. The oscillations in the thalamo-cortical and hippocampal circuitry including the physiology of the place cells and the grid cells provide a frame of reference for the analysis of delta, theta, beta, alpha (incl.mu), and gamma oscillations recorded in the space field of human performance. Based on recent neuronal models facilitating the distinction between the different dynamic regimes (selective gating and binding) in these different oscillations we suggest an integrated approach articulating together the classical biomechanical factors (3D movements and EMG) and the high-density EEG and ERP signals to allow finer mathematical analysis to optimize sport performance, such as microstates, coherency/directionality analysis and neural generators. PMID:26955362

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

    PubMed Central

    2013-01-01

    Background Emotion-related attentional bias is implicated in the aetiology and maintenance of anxiety disorders. Electroencephalogram (EEG) biofeedback can obviously improve the anxiety disorders and reduce stress level, and can also enhance attention performance in healthy subjects. The present study examined the effects and mechanisms of EEG biofeedback training on the attentional bias of high trait anxiety (HTA) individuals toward negative stimuli. Results Event-related potentials were recorded while HTA (n=24) and nonanxious (n=21) individuals performed the color-word emotional Stroop task. During the emotional Stroop task, HTA participants showed longer reaction times and P300 latencies induced by negative words, compared to nonanxious participants. The EEG biofeedback significantly decreased the trait anxiety inventory score and reaction time in naming the color of negative words in the HTA group. P300 latencies evoked by negative stimuli in the EEG biofeedback group were significantly reduced after the alpha training, while no significant changes were observed in the sham biofeedback group after the intervention. Conclusion The prolonged P300 latency is associated with attentional bias to negative stimuli in the HTA group. EEG biofeedback training demonstrated a significant improvement of negative emotional attentional bias in HTA individuals, which may be due to the normalization of P300 latency. PMID:24099141

  1. Simultaneous MEG and intracranial EEG recordings during attentive reading.

    PubMed

    Dalal, Sarang S; Baillet, Sylvain; Adam, Claude; Ducorps, Antoine; Schwartz, Denis; Jerbi, Karim; Bertrand, Olivier; Garnero, Line; Martinerie, Jacques; Lachaux, Jean-Philippe

    2009-05-01

    The relationship between neural oscillations recorded at various spatial scales remains poorly understood partly due to an overall dearth of studies utilizing simultaneous measurements. In an effort to study quantitative markers of attention during reading, we performed simultaneous magnetoencephalography (MEG) and intracranial electroencephalography (iEEG) recordings in four epileptic patients. Patients were asked to attend to a specific color when presented with an intermixed series of red words and green words, with words of a given color forming a cohesive story. We analyzed alpha, beta, and gamma band oscillatory responses to the word presentation and compared the strength and spatial organization of those responses in both electrophysiological recordings. Time-frequency analysis of iEEG revealed a network of clear attention-modulated high gamma band (50-150 Hz) power increases and alpha/beta (9-25 Hz) suppressions in response to the words. In addition to analyses at the sensor level, MEG time-frequency analysis was performed at the source level using a sliding window beamformer technique. Strong alpha/beta suppressions were observed in MEG reconstructions, in tandem with iEEG effects. While the MEG counterpart of high gamma band enhancement was difficult to interpret at the sensor level in two patients, MEG time-frequency source reconstruction revealed additional activation patterns in accordance with iEEG results. Importantly, iEEG allowed us to confirm that several sources of gamma band modulation observed with MEG were indeed of cortical origin rather than EMG muscular or ocular artifact. PMID:19349241

  2. Plasma levels of elastase-specific fibrinopeptides correlate with proteinase inhibitor phenotype. Evidence for increased elastase activity in subjects with homozygous and heterozygous deficiency of alpha 1-proteinase inhibitor.

    PubMed Central

    Weitz, J I; Silverman, E K; Thong, B; Campbell, E J

    1992-01-01

    There is indirect evidence that unopposed human neutrophil elastase (HNE) is responsible for emphysema in patients with alpha 1-proteinase inhibitor (Pi) deficiency. To directly explore this possibility, we developed an assay for fibrinopeptide A alpha 1-21 and its degradation products and used it to measure HNE activity in 128 subjects of known Pi phenotype. The mean elastase-specific fibrinopeptide (ESF) level in 49 deficient PiZ individuals is significantly higher than that in 56 PiMZ heterozygotes (4.5 and 1.5 nM, respectively; P less than 0.01), while the mean ESF value in heterozygotes is significantly elevated over that in 23 normal PiM subjects (1.5 and 0.6 nM, respectively; P less than 0.01), consistent with increased HNE activity in those deficient in the major regulator of the enzyme. These results are not due to differences in smoking history because after correction for pack-years of smoking, ESF values in PiZ subjects are fourfold higher than those in PiMZ individuals (P = 0.005), while the ESF levels in heterozygotes are threefold higher than those in PiM subjects (P = 0.02). In addition, this analysis suggests that cigarette smoking and alpha 1-proteinase inhibitor deficiency have additive effects on ESF levels thereby explaining why PiZ and some PiMZ individuals are at especially high risk for the development of lung disease if they smoke. Finally, the observation that ESF levels in nonsmoking PiZ subjects are inversely related to the percent of predicted forced expiratory volume in 1 s (FEV 1%) provides direct support for the concept that unregulated HNE activity causes alveolar septal destruction in patients with alpha 1-proteinase inhibitor deficiency. PMID:1541671

  3. EEG activity in Carmelite nuns during a mystical experience.

    PubMed

    Beauregard, Mario; Paquette, Vincent

    2008-10-17

    Mystical experiences relate to a fundamental dimension of human existence. These experiences, which are characterized by a sense of union with God, are commonly reported across all cultures. To date, no electroencephalography (EEG) study has been conducted to identify the neuroelectrical correlates of such experiences. The main objective of this study was to measure EEG spectral power and coherence in 14 Carmelite nuns during a mystical experience. EEG activity was recorded from 19 scalp locations during a resting state, a control condition and a mystical condition. In the mystical condition compared to control condition, electrode sites showed greater theta power at F3, C3, P3, Fz, Cz and Pz, and greater gamma1 power was detected at T4 and P4. Higher delta/beta ratio, theta/alpha ratio and theta/beta ratio were found for several electrode sites. In addition, FP1-C3 pair of electrodes displayed greater coherence for theta band while F4-P4, F4-T6, F8-T6 and C4-P4 pairs of electrodes showed greater coherence for alpha band. These results indicate that mystical experiences are mediated by marked changes in EEG power and coherence. These changes implicate several cortical areas of the brain in both hemispheres. PMID:18721862

  4. EEG sources in a group of patients with major depressive disorders.

    PubMed

    Ricardo-Garcell, Josefina; Gonzlez-Olvera, Jorge J; Miranda, Edgar; Harmony, Thala; Reyes, Ernesto; Almeida, Luis; Galn, Ldice; Daz, Daniela; Ramrez, Lizeth; Fernndez-Bouzas, Antonio; Aubert, Eduardo

    2009-01-01

    EEG sources were assessed in a group of patients with major moderate-severe depressive disorder (MDD) as classified by trained clinicians according to DSM-IV criteria. Frequency Domain Variable Resolution Electromagnetic Tomography (FD-VARETA) was used to calculate EEG sources. The Z-values indicated that EEG sources were abnormal (increase in current density) in all patients, with most demonstrating abnormal EEG sources in both hemispheres but with maximal inverse solution located primarily in the right. Twenty-nine patients had a predominant topography of the abnormal EEG maximal inverse solution in the frontal lobes. The remaining seven patients had a bilateral abnormal increase in current density in the superior parietal lobe. The EEG maximal abnormal inverse solution frequency was observed in both hemispheres such that the increases in current density were prevalent in alpha and theta bands. The results suggest that any of the two hemispheres could be affected by MDD, but abnormal EEG sources can be found more frequently in the right one, with the maximal abnormal inverse solution at the alpha and theta bands in frontal and parietal cortices. PMID:18755226

  5. Diagnostic Accuracy of microEEG: A Miniature, Wireless EEG Device

    PubMed Central

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

    2014-01-01

    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). 225 ED patients with AMS underwent 3 EEGs. EEG1 (Nicolet Monitor, reference) and EEG2 (microEEG) were recorded simultaneously with EEG cup electrodes using a signal splitter. 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 & specificity of these interpretations relative to EEG1-GS, and to compute a diagnostic odds ratio (DOR). 79% of EEG1-GS were abnormal. Neither the DOR nor ?f representing interrater reliabilities differed significantly between EEG1, EEG2, and EEG3. Mean setup time was 27 minutes for EEG1/EEG2 and 12 minutes for EEG3. Mean electrode impedance of EEG3 recordings was 12.6 k? (SD 31.9 k?). DA 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

  6. EEG Topographic Mapping of Visual and Kinesthetic Imagery in Swimmers.

    PubMed

    Wilson, V E; Dikman, Z; Bird, E I; Williams, J M; Harmison, R; Shaw-Thornton, L; Schwartz, G E

    2016-03-01

    This study investigated differences in QEEG measures between kinesthetic and visual imagery of a 100-m swim in 36 elite competitive swimmers. Background information and post-trial checks controlled for the modality of imagery, swimming skill level, preferred imagery style, intensity of image and task equality. Measures of EEG relative magnitude in theta, low (7-9 Hz) and high alpha (8-10 Hz), and low and high beta were taken from 19 scalp sites during baseline, visual, and kinesthetic imagery. QEEG magnitudes in the low alpha band during the visual and kinesthetic conditions were attenuated from baseline in low band alpha but no changes were seen in any other bands. Swimmers produced more low alpha EEG magnitude during visual versus kinesthetic imagery. This was interpreted as the swimmers having a greater efficiency at producing visual imagery. Participants who reported a strong intensity versus a weaker feeling of the image (kinesthetic) had less low alpha magnitude, i.e., there was use of more cortical resources, but not for the visual condition. These data suggest that low band (7-9 Hz) alpha distinguishes imagery modalities from baseline, visual imagery requires less cortical resources than kinesthetic imagery, and that intense feelings of swimming requires more brain activity than less intense feelings. PMID:26420001

  7. Classification of Single Normal and Alzheimer's Disease Individuals from Cortical Sources of Resting State EEG Rhythms

    PubMed Central

    Babiloni, Claudio; Triggiani, Antonio I.; Lizio, Roberta; Cordone, Susanna; Tattoli, Giacomo; Bevilacqua, Vitoantonio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Millán-Calenti, José C.; Buján, Ana; Tortelli, Rosanna; Cardinali, Valentina; Barulli, Maria Rosaria; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Frisoni, Giovanni B.; del Percio, Claudio

    2016-01-01

    Previous studies have shown abnormal power and functional connectivity of resting state electroencephalographic (EEG) rhythms in groups of Alzheimer's disease (AD) compared to healthy elderly (Nold) subjects. Here we tested the best classification rate of 120 AD patients and 100 matched Nold subjects using EEG markers based on cortical sources of power and functional connectivity of these rhythms. EEG data were recorded during resting state eyes-closed condition. Exact low-resolution brain electromagnetic tomography (eLORETA) estimated the power and functional connectivity of cortical sources in frontal, central, parietal, occipital, temporal, and limbic regions. Delta (2–4 Hz), theta (4–8 Hz), alpha 1 (8–10.5 Hz), alpha 2 (10.5–13 Hz), beta 1 (13–20 Hz), beta 2 (20–30 Hz), and gamma (30–40 Hz) were the frequency bands of interest. The classification rates of interest were those with an area under the receiver operating characteristic curve (AUROC) higher than 0.7 as a threshold for a moderate classification rate (i.e., 70%). Results showed that the following EEG markers overcame this threshold: (i) central, parietal, occipital, temporal, and limbic delta/alpha 1 current density; (ii) central, parietal, occipital temporal, and limbic delta/alpha 2 current density; (iii) frontal theta/alpha 1 current density; (iv) occipital delta/alpha 1 inter-hemispherical connectivity; (v) occipital-temporal theta/alpha 1 right and left intra-hemispherical connectivity; and (vi) parietal-limbic alpha 1 right intra-hemispherical connectivity. Occipital delta/alpha 1 current density showed the best classification rate (sensitivity of 73.3%, specificity of 78%, accuracy of 75.5%, and AUROC of 82%). These results suggest that EEG source markers can classify Nold and AD individuals with a moderate classification rate higher than 80%. PMID:26941594

  8. Classification of Single Normal and Alzheimer's Disease Individuals from Cortical Sources of Resting State EEG Rhythms.

    PubMed

    Babiloni, Claudio; Triggiani, Antonio I; Lizio, Roberta; Cordone, Susanna; Tattoli, Giacomo; Bevilacqua, Vitoantonio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Millán-Calenti, José C; Buján, Ana; Tortelli, Rosanna; Cardinali, Valentina; Barulli, Maria Rosaria; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Frisoni, Giovanni B; Del Percio, Claudio

    2016-01-01

    Previous studies have shown abnormal power and functional connectivity of resting state electroencephalographic (EEG) rhythms in groups of Alzheimer's disease (AD) compared to healthy elderly (Nold) subjects. Here we tested the best classification rate of 120 AD patients and 100 matched Nold subjects using EEG markers based on cortical sources of power and functional connectivity of these rhythms. EEG data were recorded during resting state eyes-closed condition. Exact low-resolution brain electromagnetic tomography (eLORETA) estimated the power and functional connectivity of cortical sources in frontal, central, parietal, occipital, temporal, and limbic regions. Delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), beta 2 (20-30 Hz), and gamma (30-40 Hz) were the frequency bands of interest. The classification rates of interest were those with an area under the receiver operating characteristic curve (AUROC) higher than 0.7 as a threshold for a moderate classification rate (i.e., 70%). Results showed that the following EEG markers overcame this threshold: (i) central, parietal, occipital, temporal, and limbic delta/alpha 1 current density; (ii) central, parietal, occipital temporal, and limbic delta/alpha 2 current density; (iii) frontal theta/alpha 1 current density; (iv) occipital delta/alpha 1 inter-hemispherical connectivity; (v) occipital-temporal theta/alpha 1 right and left intra-hemispherical connectivity; and (vi) parietal-limbic alpha 1 right intra-hemispherical connectivity. Occipital delta/alpha 1 current density showed the best classification rate (sensitivity of 73.3%, specificity of 78%, accuracy of 75.5%, and AUROC of 82%). These results suggest that EEG source markers can classify Nold and AD individuals with a moderate classification rate higher than 80%. PMID:26941594

  9. Altered resting-state EEG source functional connectivity in schizophrenia: the effect of illness duration

    PubMed Central

    Di Lorenzo, Giorgio; Daverio, Andrea; Ferrentino, Fabiola; Santarnecchi, Emiliano; Ciabattini, Fabio; Monaco, Leonardo; Lisi, Giulia; Barone, Ylenia; Di Lorenzo, Cherubino; Niolu, Cinzia; Seri, Stefano; Siracusano, Alberto

    2015-01-01

    Despite the increasing body of evidence supporting the hypothesis of schizophrenia as a disconnection syndrome, studies of resting-state EEG Source Functional Connectivity (EEG-SFC) in people affected by schizophrenia are sparse. The aim of the present study was to investigate resting-state EEG-SFC in 77 stable, medicated patients with schizophrenia (SCZ) compared to 78 healthy volunteers (HV). In order to study the effect of illness duration, SCZ were divided in those with a short duration of disease (SDD; n = 25) and those with a long duration of disease (LDD; n = 52). Resting-state EEG recordings in eyes closed condition were analyzed and lagged phase synchronization (LPS) indices were calculated for each ROI pair in the source-space EEG data. In delta and theta bands, SCZ had greater EEG-SFC than HV; a higher theta band connectivity in frontal regions was observed in LDD compared with SDD. In the alpha band, SCZ showed lower frontal EEG-SFC compared with HV whereas no differences were found between LDD and SDD. In the beta1 band, SCZ had greater EEG-SFC compared with HVs and in the beta2 band, LDD presented lower frontal and parieto-temporal EEG-SFC compared with HV. In the gamma band, SDD had greater connectivity values compared with LDD and HV. This study suggests that resting state brain network connectivity is abnormally organized in schizophrenia, with different patterns for the different EEG frequency components and that EEG can be a powerful tool to further elucidate the complexity of such disordered connectivity. PMID:25999835

  10. Quantitative EEG of Rapid-Eye-Movement Sleep: A Marker of Amnestic Mild Cognitive Impairment.

    PubMed

    Brayet, Pauline; Petit, Dominique; Frauscher, Birgit; Gagnon, Jean-François; Gosselin, Nadia; Gagnon, Katia; Rouleau, Isabelle; Montplaisir, Jacques

    2016-04-01

    The basal forebrain cholinergic system, which is impaired in early Alzheimer's disease, is more crucial for the activation of rapid-eye-movement (REM) sleep electroencephalogram (EEG) than it is for wakefulness. Quantitative EEG from REM sleep might thus provide an earlier and more accurate marker of the development of Alzheimer's disease in subjects with mild cognitive impairment (MCI) subjects than that from wakefulness. To assess the superiority of the REM sleep EEG as a screening tool for preclinical Alzheimer's disease, 22 subjects with amnestic MCI (a-MCI; 63.9 ± 7.7 years), 10 subjects with nonamnestic MCI (na-MCI; 64.1 ± 4.5 years) and 32 controls (63.7 ± 6.6 years) participated in the study. Spectral analyses of the waking EEG and REM sleep EEG were performed and the [(delta + theta)/(alpha + beta)] ratio was used to assess between-group differences in EEG slowing. The a-MCI subgroup showed EEG slowing in frontal lateral regions compared to both na-MCI and control groups. This EEG slowing was present in wakefulness (compared to controls) but was much more prominent in REM sleep. Moreover, the comparison between amnestic and nonamnestic subjects was found significant only for the REM sleep EEG. There was no difference in EEG power ratio between na-MCI and controls for any of the 7 cortical regions studied. These findings demonstrate the superiority of the REM sleep EEG in the discrimination between a-MCI and both na-MCI and control subjects. PMID:26323578

  11. EEG Studies with Young Children.

    ERIC Educational Resources Information Center

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

    2000-01-01

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

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

    PubMed

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

    2014-10-01

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

  13. Postictal generalized EEG suppression

    PubMed Central

    Lamberts, Robert J.; Gaitatzis, Athanasios; Sander, Josemir W.; Elger, Christian E.

    2013-01-01

    Objective: To determine the consistency and facilitating cofactors of postictal generalized EEG suppression (PGES) of >20 seconds after convulsive seizures (CS), a suggested predictor of sudden unexpected death in epilepsy risk. Methods: We retrospectively reviewed video-EEG data of people with ≥2 recorded CS. Presence and duration of PGES were assessed by 2 independent observers blinded to patient status. Intraindividual consistency of PGES >20 seconds was determined and correlations with clinical characteristics were analyzed after correction for individual effects and the varying number of seizures. Results: One hundred fifty-four seizures in 59 people were analyzed. PGES >20 seconds was found in 37 individuals (63%) and 57 (37%) of CS. The proportion of persons in whom PGES occurred consistently (presence or absence of PGES >20 seconds in all CS) was lower in those with more CS. PGES of >20 seconds was more frequent in seizures arising from sleep (odds ratio 3.29, 95% confidence interval 1.21–8.96) and when antiepileptic medication was tapered (odds ratio 4.80, 95% confidence interval 1.27–18.14). Conclusion: Apparent PGES consistency was less frequent in people with more CS recorded, suggesting that PGES is an inconsistent finding in any one individual. Thus, we believe that PGES >20 seconds is not a reliable predictor of sudden unexpected death in epilepsy. Sleep and antiepileptic drug reduction appear to facilitate the occurrence of PGES. PMID:23966251

  14. Dry EEG Electrodes

    PubMed Central

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

    2014-01-01

    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

  15. EEG recording and analysis for sleep research.

    PubMed

    Campbell, Ian G

    2009-10-01

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

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

    PubMed Central

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

    2015-01-01

    Summary Lysosomal α-galactosidase A (α-Gal) is the enzyme deficient in Fabry disease (FD), an X-linked glycosphingolipidosis caused by pathogenic mutations affecting the GLA gene. The early-onset, multi-systemic FD classical phenotype is associated with absent or severe enzyme deficiency, as measured by in vitro assays, but patients with higher levels of residual α-Gal activity may have later-onset, more organ-restricted clinical presentations. A change in the codon 118 of the wild-type α-Gal sequence, replacing basic arginine by a potentially sulfhydryl-binding cysteine residue – GLA p.(Arg118Cys) –, has been recurrently described in large FD screening studies of high-risk patients. Although the Cys118 allele is associated with high residual α-Gal activity in vitro, it has been classified as a pathogenic mutation, mainly on the basis of theoretical arguments about the chemistry of the cysteine residue. However its pathogenicity has never been convincingly demonstrated by pathology criteria. We reviewed the clinical, biochemical and histopathology data obtained from 22 individuals of Portuguese and Spanish ancestry carrying the Cys118 allele, including 3 homozygous females. Cases were identified either on the differential diagnosis of possible FD manifestations and on case-finding studies (n=11; 4 males), or on unbiased cascade screening of probands’ close relatives (n=11; 3 males). Overall, those data strongly suggest that the GLA p.(Arg118Cys) variant does not segregate with FD clinical phenotypes in a Mendelian fashion, but might be a modulator of the multifactorial risk of cerebrovascular disease, since the allelic frequency in stroke patients was 0.0087 (p=0.0185 vs the general population). The Cys118 allelic frequency in healthy Portuguese adults (n=696) has been estimated as 0.001, therefore not qualifying for “rare” condition. PMID:25468652

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

    PubMed

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

    2015-02-01

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

  18. A capacitive, biocompatible and adhesive electrode for long-term and cap-free monitoring of EEG signals

    NASA Astrophysics Data System (ADS)

    Lee, Seung Min; Kim, Jeong Hun; Byeon, Hang Jin; Choi, Yoon Young; Park, Kwang Suk; Lee, Sang-Hoon

    2013-06-01

    Objective. Long-term electroencephalogram (EEG) monitoring broadens EEG applications to various areas, but it requires cap-free recording of EEG signals. Our objective here is to develop a capacitive, small-sized, adhesive and biocompatible electrode for the cap-free and long-term EEG monitoring. Approach. We have developed an electrode made of polydimethylsiloxane (PDMS) and adhesive PDMS for EEG monitoring. This electrode can be attached to a hairy scalp and be completely hidden by the hair. We tested its electrical and mechanical (adhesive) properties by measuring voltage gain to frequency and adhesive force using 30 repeat cycles of the attachment and detachment test. Electrode performance on EEG was evaluated by alpha rhythm detection and measuring steady state visually evoked potential and N100 auditory evoked potential. Main results. We observed the successful recording of alpha rhythm and evoked signals to diverse stimuli with high signal quality. The biocompatibility of the electrode was verified and a survey found that the electrode was comfortable and convenient to wear. Significance. These results indicate that the proposed EEG electrode is suitable and convenient for long term EEG monitoring.

  19. Modulation of the COMT Val158Met polymorphism on resting-state EEG power

    PubMed Central

    Solís-Ortiz, Silvia; Pérez-Luque, Elva; Gutiérrez-Muñoz, Mayra

    2015-01-01

    The catechol-O-methyltransferase (COMT) Val158Met polymorphism impacts cortical dopamine (DA) levels and may influence cortical electrical activity in the human brain. This study investigated whether COMT genotype influences resting-state electroencephalogram (EEG) power in the frontal, parietal and midline regions in healthy volunteers. EEG recordings were conducted in the resting-state in 13 postmenopausal healthy woman carriers of the Val/Val genotype and 11 with the Met/Met genotype. The resting EEG spectral absolute power in the frontal (F3, F4, F7, F8, FC3 and FC4), parietal (CP3, CP4, P3 and P4) and midline (Fz, FCz, Cz, CPz, Pz and Oz) was analyzed during the eyes-open and eyes-closed conditions. The frequency bands considered were the delta, theta, alpha1, alpha2, beta1 and beta2. EEG data of the Val/Val and Met/Met genotypes, brain regions and conditions were analyzed using a general linear model analysis. In the individuals with the Met/Met genotype, delta activity was increased in the eyes-closed condition, theta activity was increased in the eyes-closed and in the eyes-open conditions, and alpha1 band, alpha2 band and beta1band activity was increased in the eyes-closed condition. A significant interaction between COMT genotypes and spectral bands was observed. Met homozygote individuals exhibited more delta, theta and beta1 activity than individuals with the Val/Val genotype. No significant interaction between COMT genotypes and the resting-state EEG regional power and conditions were observed for the three brain regions studied. Our findings indicate that the COMT Val158Met polymorphism does not directly impact resting-state EEG regional power, but instead suggest that COMT genotype can modulate resting-state EEG spectral power in postmenopausal healthy women. PMID:25883560

  20. Ballistocardiogram Artifact Removal with a Reference Layer and Standard EEG Cap

    PubMed Central

    Luo, Qingfei; Huang, Xiaoshan; Glover, Gary H.

    2014-01-01

    Background In simultaneous EEG-fMRI, the EEG recordings are severely contaminated by ballistocardiogram (BCG) artifacts, which are caused by cardiac pulsations. To reconstruct and remove the BCG artifacts, one promising method is to measure the artifacts in the absence of EEG signal by placing a group of electrodes (BCG electrodes) on a conductive layer (reference layer) insulated from the scalp. However, current BCG reference layer (BRL) methods either use a customized EEG cap composed of electrode pairs, or need to construct the custom reference layer through additional model-building experiments for each EEG-fMRI experiment. These requirements have limited the versatility and efficiency of BRL. The aim of this study is to propose a more practical and efficient BRL method and compare its performance with the most popular BCG removal method, the optimal basis sets (OBS) algorithm. New Method By designing the reference layer as a permanent and reusable cap, the new BRL method is able to be used with a standard EEG cap, and no extra experiments and preparations are needed to use the BRL in an EEG-fMRI experiment. Results The BRL method effectively removed the BCG artifacts from both oscillatory and evoked potential scalp recordings and recovered the EEG signal. Comparison with Existing Method Compared to the OBS, this new BRL method improved the contrast-to-noise ratios of the alpha-wave, visual, and auditory evoked potential signals by 101%, 76%, and 75% respectively, employing 160 BCG electrodes. Using only 20 BCG electrodes, the BRL improved the EEG signal by 74%/26%/41% respectively. Conclusion The proposed method can substantially improve the EEG signal quality compared with traditional methods. PMID:24960423

  1. Power spectral density and coherence analysis of Alzheimer's EEG.

    PubMed

    Wang, Ruofan; Wang, Jiang; Yu, Haitao; Wei, Xile; Yang, Chen; Deng, Bin

    2015-06-01

    In this paper, we investigate the abnormalities of electroencephalograph (EEG) signals in the Alzheimer's disease (AD) by analyzing 16-scalp electrodes EEG signals and make a comparison with the normal controls. The power spectral density (PSD) which represents the power distribution of EEG series in the frequency domain is used to evaluate the abnormalities of AD brain. Spectrum analysis based on autoregressive Burg method shows that the relative PSD of AD group is increased in the theta frequency band while significantly reduced in the alpha2 frequency bands, particularly in parietal, temporal, and occipital areas. Furthermore, the coherence of two EEG series among different electrodes is analyzed in the alpha2 frequency band. It is demonstrated that the pair-wise coherence between different brain areas in AD group are remarkably decreased. Interestingly, this decrease of pair-wise electrodes is much more significant in inter-hemispheric areas than that in intra-hemispheric areas. Moreover, the linear cortico-cortical functional connectivity can be extracted based on coherence matrix, from which it is shown that the functional connections are obviously decreased, the same variation trend as relative PSD. In addition, we combine both features of the relative PSD and the normalized degree of functional network to discriminate AD patients from the normal controls by applying a support vector machine model in the alpha2 frequency band. It is indicated that the two groups can be clearly classified by the combined feature. Importantly, the accuracy of the classification is higher than that of any one feature. The obtained results show that analysis of PSD and coherence-based functional network can be taken as a potential comprehensive measure to distinguish AD patients from the normal, which may benefit our understanding of the disease. PMID:25972978

  2. Envelope responses in single-trial EEG indicate attended speaker in a ‘cocktail party’

    NASA Astrophysics Data System (ADS)

    Horton, Cort; Srinivasan, Ramesh; D'Zmura, Michael

    2014-08-01

    Objective. Recent studies have shown that auditory cortex better encodes the envelope of attended speech than that of unattended speech during multi-speaker (‘cocktail party’) situations. We investigated whether these differences were sufficiently robust within single-trial electroencephalographic (EEG) data to accurately determine where subjects attended. Additionally, we compared this measure to other established EEG markers of attention. Approach. High-resolution EEG was recorded while subjects engaged in a two-speaker ‘cocktail party’ task. Cortical responses to speech envelopes were extracted by cross-correlating the envelopes with each EEG channel. We also measured steady-state responses (elicited via high-frequency amplitude modulation of the speech) and alpha-band power, both of which have been sensitive to attention in previous studies. Using linear classifiers, we then examined how well each of these features could be used to predict the subjects’ side of attention at various epoch lengths. Main results. We found that the attended speaker could be determined reliably from the envelope responses calculated from short periods of EEG, with accuracy improving as a function of sample length. Furthermore, envelope responses were far better indicators of attention than changes in either alpha power or steady-state responses. Significance. These results suggest that envelope-related signals recorded in EEG data can be used to form robust auditory BCI’s that do not require artificial manipulation (e.g., amplitude modulation) of stimuli to function.

  3. Analysis of postarousal EEG activity during somnambulistic episodes.

    PubMed

    Zadra, Antonio; Pilon, Mathieu; Joncas, Steve; Rompré, Sylvie; Montplaisir, Jacques

    2004-09-01

    Early studies found that electroencephalographic (EEG) recordings during somnambulistic episodes were characterized by a combination of alpha, theta, and delta frequencies, without evidence of clear wakefulness. Three postarousal EEG patterns associated with slow-wave sleep (SWS) arousals were recently identified in adults with sleepwalking and sleep terrors. The goal of the present study was to evaluate the distribution of these postarousal EEG patterns in 10 somnambulistic patients (three males, seven females, mean age: 25.1, SD: 4.1) evaluated at baseline and following 38 h of sleep deprivation. A total of 44 behavioral arousals were recorded in the laboratory; seven episodes at baseline (five from SWS, two from stage 2 sleep) and 37 episodes during recovery sleep (30 from SWS, seven from stage 2 sleep). There was no significant difference in the distribution of postarousal EEG patterns identified during baseline and recovery sleep. One pattern, comprised of diffuse rhythmic and synchronous delta activity, was preferentially associated with relatively simple behavioral episodes but did not occur during episodes from stage 2 sleep. Overall, delta activity was detected in 48% of the behavioral episodes from SWS and in 22% of those from stage 2. There was no evidence of complete awakening during any of the episodes. The results support the view of somnambulism as a disorder of arousal and suggest that sleepwalkers' atypical arousal reactions can manifest themselves in stage 2 sleep in addition to SWS. PMID:15339264

  4. Relation between psychometric tests and quantitative topographic EEG in pharmacology.

    PubMed

    Schober, F; Dimpfel, W

    1992-11-01

    Both, psychometric tests and quantitative pharmaco-EEG are accepted as necessary tools in different fields of pharmacology. But using these methods separately, none is able to forward informations about the behavioral performance and the central nervous demand simultaneously. The solution of this problem is a complex psychophysiological set-up. Till today such complex measurement set-ups are a rarity. The main reason is the impossibility of EEG recordings during psychometric tests without different artefacts. In the present paper we demonstrate by using our own CATEEM-System in connection with the IBIS-Psychometry-system the possibility to get artefact free EEG recordings during psychometric test conditions. The different mental loads at different tests are producing a graduated increase in the delta and theta frequency range of the EEG of the fronto-temporal region and the occipital region of the cortex. During the tests a decrease of alpha-activity is seen generally. These effects can be described quantitatively as the topographical distribution of frequency changes. The present data are in line with the knowledge about the functional and anatomical structure of the human brain. PMID:1490768

  5. Effect of donepezil on EEG spectral analysis in Alzheimer's disease.

    PubMed

    Balkan, Sevin; Yaraş, Nazmi; Mihçi, Ebru; Dora, Babür; Ağar, Aysel; Yargiçoğlu, Piraye

    2003-09-01

    EEG spectral analysis allows a quantitative analysis of changes in the frequency bands during disease progression in Alzheimer's disease (AD) and could be used to monitor treatment and disease progression. Eighteen patients with probable AD were evaluated by Folstein Mini Mental State Examination (MMSE) and EEG spectral analysis before donepezil treatment, 2 months after 5 mg/day and 4 months after the dose was raised to 10 mg/day. EEG evaluations were done in 4 derivations (T3-T5, T4-T6, C3-P3, C4-P4). Six months after treatment there was a significant reduction in the temporal delta amplitudes and an increase in the amplitudes of all the other frequency ranges including theta amplitudes both in the temporal and centroparietal derivations. MMSE scores increased during treatment but the change was not significant. These findings show that donepezil exerts a positive effect on EEG in AD by decreasing delta activity and increasing alpha and beta activity. The increase in theta activity after treatment may reflect a therapeutic shift of delta activity to theta activity. PMID:14626697

  6. Effects of Early Intervention on EEG Power and Coherence in Previously Institutionalized Children in Romania

    PubMed Central

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

    2012-01-01

    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. Due to a policy of non-interference, 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

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  8. Effect of Low-Level Laser Stimulation on EEG Power in Normal Subjects with Closed Eyes

    PubMed Central

    Chang, Yang-Chyuan

    2013-01-01

    In a previous study, we found that the low-level laser (LLL) stimulation at the palm with a frequency of 10 Hz was able to induce significant brain activation in normal subjects with opened eyes. However, the electroencephalography (EEG) changes to LLL stimulation in subjects with closed eyes have not been studied. In the present study, the laser array stimulator was applied to deliver insensible laser stimulations to the palm of the tested subjects with closed eyes (the laser group). The EEG activities before, during, and after the laser stimulation were collected. The EEG amplitude powers of each EEG frequency band at 19 locations were calculated. These power data were then analyzed by SPSS software using repeated-measure ANOVAs and appropriate posthoc tests. We found a pronounced decrease in the EEG power in alpha-bandwidth during laser simulation and then less decrease in the EEG power in delta-bandwidth in normal subjects with laser stimulation. The EEG power in beta-bandwidth in the right occipital area also decreased significantly in the laser group. We suggest that LLL stimulation might be conducive to falling into sleep in patients with sleep problems. PMID:24288562

  9. Optimizing microsurgical skills with EEG neurofeedback

    PubMed Central

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

    2009-01-01

    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. PMID:19630948

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

    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.

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

    PubMed

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

    2011-04-01

    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

  13. Frontal alpha asymmetry and sexually motivated states.

    PubMed

    Prause, Nicole; Staley, Cameron; Roberts, Verena

    2014-03-01

    Anterior alpha asymmetry of electroencephalographic (EEG) signals has been suggested to index state approach (or avoidance) motivation. This model has not yet been extended to high approach-motivation sexual stimuli, which may represent an important model of reward system function. Sixty-five participants viewed a neutral and a sexually motivating film while their EEG was recorded, and reported their sexual feelings after each film. Greater alpha power in the left hemisphere during sexually motivated states was evident. A positive relationship between self-reported mental sexual arousal and alpha asymmetry was identified, where coherence between these indicators was higher in women. Notably, coherence was stronger when mental versus physical sexual arousal was rated. Alpha asymmetry appears to offer a new method for further examining this novel coherence pattern across men and women. PMID:24460762

  14. EEG frequency analysis in obsessive-compulsive disorder.

    PubMed

    Drake, M E; Pakalnis, A; Newell, S A

    1996-01-01

    The cerebral basis of obsessions and compulsions has attracted increasing attention in neuropsychology and neuropsychiatry. Clinical and imaging studies have suggested frontal lobe dysfunction in some cases of obsessive-compulsive disorder and Tourette syndrome with obsessional symptoms. We compared EEG spectral measures in 20 such patients not taking medications and 12 neurologically intact unmedicated controls. EEG was recorded from O1-A1+A2, O2-A1+A2, Fz-A1+A2, F7-C3, F8-C4, T5-O1 and T6-O2. One-minute epochs of artifact-free EEG were used for compressed spectral array and calculation of time domain descriptors. We measured modal alpha frequency (MAF), maximal alpha frequency (MxAF), spectral edge frequency and spectral mobility in left and right frontal regions (MOLF and MORF). MAF and MxAF were reduced in the frontal regions in patients as compared to controls, and MOLF and MORF were both lower. No significant differences between patients and controls were found in the temporal or occipital areas. These observations support the suggestions of a physiologic basis for obsessions and compulsions, and of frontal lobe disturbance in their pathophysiology. PMID:8927236

  15. Spectral analysis of EEG in normal and sulfite oxidase deficient rats under sulfite administration.

    PubMed

    Ozkaya, Yaşar Gül; Küçükatay, Vural; Savcioğlu, Feyza; Ağar, Aysel; Yargicoğlu, Piraye; Onal, Mehmet Zülküf

    2006-11-01

    This article investigated the possible neurotoxic effect of sulfite in normal and sulfite oxidase (SOX) deficients rats by evaluating EEG spectral analysis. Rats were divided into four groups: control (C), sulfite treated (25 mg/kg) (ST), SOX deficient (SD), and sulfite treated SOX deficient (STSD) groups. The qEEG spectral analyses of two spectral parameters including power and relative power were performed. The mean power of SD group was found to be increased compared to the all other groups and returned to control levels after sulfite administration. The power of the four frequency bands (delta, theta, alpha, beta) of the SD group corresponds to the mean power. EEG relative power increased in the delta band with concomitant decreases in power measured in the alpha frequency range. It was concluded that exogenous administration of sulfite affected the brain electrical activity in SOX deficiency, and improved neuroprotection. PMID:17000536

  16. Distinguishing Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion from Prolonged Febrile Seizures by Acute Phase EEG Spectrum Analysis

    PubMed Central

    Oguri, Masayoshi; Saito, Yoshiaki; Fukuda, Chisako; Kishi, Kazuko; Yokoyama, Atsushi; Lee, Sooyoung; Torisu, Hiroyuki; Toyoshima, Mitsuo; Sejima, Hitoshi; Kaji, Shunsaku; Hamano, Shin-ichiro; Okanishi, Toru; Tomita, Yutaka; Maegaki, Yoshihiro

    2016-01-01

    Background To differentiate the features of electroencephalography (EEG) after status epileptics in febrile children with final diagnosis of either febrile seizure (FS) or acute encephalopathy for an early diagnosis. Methods We retrospectively collected data from 68 children who had status epilepticus and for whom EEGs were recorded within 120 h. These included subjects with a final diagnosis of FS (n = 20), epileptic status (ES; n = 11), acute encephalopathy with biphasic seizures and late reduced diffusion (AESD; n = 18), mild encephalopathy with a reversible splenial lesion (MERS; n = 7), other febrile encephalopathies (n = 10), hypoxic-ischemic encephalopathy (n = 1), and intracranial bleeding (n = 1). Initially, all EEGs were visually assessed and graded, and correlation with outcome was explored. Representative EEG epochs were then selected for quantitative analyses. Furthermore, data from AESD (n = 7) and FS (n = 16) patients for whom EEG was recorded within 24 h were also compared. Results Although milder and most severe grades of EEG correlated with neurological outcome, the outcome of moderate EEG severity group was variable and was not predictable from usual inspection. Frequency band analysis revealed that solid delta power was not significantly different among the five groups (AESD, MERS, FS, ES and control), and that MERS group showed the highest theta band power. The ratios of delta/alpha and (delta + theta)/(alpha + beta) band powers were significantly higher in the AESD group than in other groups. The alpha and beta band powers in EEGs within 24 h from onset were significantly lower in the AESD group. The band powers and their ratios showed earlier improvement towards 24 h in FS than in AESD. Conclusion Sequential EEG recording up to 24 h from onset appeared to be helpful for distinction of AESD from FS before emergence of the second phase of AESD. PMID:27046946

  17. A correlation study of contingent negative variation, reaction time, and EEG power spectrum in control and psychopathological populations.

    PubMed

    Mantanus, H; Timsit-Berthier, M; Gerono, A; von Frenckell, R

    1981-12-01

    Contingent negative variation (CNV), reaction time (RT), and EEG power spectrum were measured in a group of 27 neurotics and 26 controls subjects, male and female, aged 18 to 38. CNV was recorded with a 1 sec interstimulus interval and averaged over 48 trials. Two spectral analyses of the EEG were performed, the first during the 1 sec period preceding S1 (spontaneous EEG), the second during the S1-S2 interval (activated EEG). For each group of subjects, we calculated the correlations between four measures of CNV amplitude, RT duration, and the relative powers of the delta, theta, alpha and beta activities during spontaneous and activated EEG. In neurotic subjects there was an absence of correlation between the pre- and post-imperative segments of the CNV, and between early CNV amplitude and per cent alpha power. Both groups shared in common strong correlations relating CNV amplitude and RT length, on the one hand, and the different components of the EEG spectrum, on the other hand, Principal component analysis applied to the pooled data revealed different factors for CNV and EEG parameters, suggesting independence of the neurophysiological mechanisms implied in the two phenomena. PMID:7342992

  18. [General Features of the Formation of EEG Wave Structure in Children and Adolescents Living in Northern European Russia].

    PubMed

    Soroko, S I; Bekshaev, S S; Rozhkov, V P; Nagornova, Zh V; Shemyakina, N V

    2015-01-01

    The article presents the results of the analysis of EEG wave structure formation in children and adolescents aged 7-18 years living under severe conditions of the North. The approaches developed in discrete mathematics (the graph theory, the theory of network flows) were used to assess the time-frequency transformations of EEG patterns. We evaluated conditional probabilities of reciprocal transitions between the components of six frequency bands of E EG (delta, theta, alpha-1, alpha-2, beta-1, beta-2). We described age- and sex-related features as well as regional specificities of the EEG wave structure. We defined the age periods of reorganization of diffuse EEG activities into the main EEG rhythms; the role of distinct rhythms in the maintenance of the EEG wave structure and its dynamic rearrangements was also discussed. The age-related changes of the structure of EEG patterns form some general picture of the morphofunctional development of brain in children and adolescents at different stages of postnatal ontogenesis under severe climate and socio-economic conditions of the North. PMID:26485790

  19. Plastic modulation of PTSD resting-state networks by EEG neurofeedback

    PubMed Central

    Kluetsch, Rosemarie C.; Ros, Tomas; Théberge, Jean; Frewen, Paul A.; Calhoun, Vince D.; Schmahl, Christian; Jetly, Rakesh; Lanius, Ruth A.

    2015-01-01

    Objective Electroencephalographic (EEG) neurofeedback training has been shown to produce plastic modulations in salience network and default mode network functional connectivity in healthy individuals. In this study, we investigated whether a single session of neurofeedback training aimed at the voluntary reduction of alpha rhythm (8–12 Hz) amplitude would be related to differences in EEG network oscillations, functional MRI (fMRI) connectivity, and subjective measures of state anxiety and arousal in a group of individuals with PTSD. Method 21 individuals with PTSD related to childhood abuse underwent 30 minutes of EEG neurofeedback training preceded and followed by a resting-state fMRI scan. Results Alpha desynchronizing neurofeedback was associated with decreased alpha amplitude during training, followed by a significant increase (‘rebound’) in resting-state alpha synchronization. This rebound was linked to increased calmness, greater salience network connectivity with the right insula, and enhanced default mode network connectivity with bilateral posterior cingulate, right middle frontal gyrus, and left medial prefrontal cortex. Conclusion Our study represents a first step in elucidating the potential neurobehavioral mechanisms mediating the effects of neurofeedback treatment on regulatory systems in PTSD. Moreover, it documents for the first time a spontaneous EEG ‘rebound’ after neurofeedback, pointing to homeostatic/compensatory mechanisms operating in the brain. PMID:24266644

  20. EEG deficits in chronic marijuana abusers during monitored abstinence: preliminary findings.

    PubMed

    Herning, Ronald I; Better, Warren; Tate, Kimberly; Cadet, Jean L

    2003-05-01

    Cognitive, cerebrovascular, and psychiatric impairments have been documented with chronic marijuana users. To better understand the nature and duration of these neurocognitive changes in marijuana abusers, we recorded the resting EEG of 29 abstinent chronic marijuana abusers and 21 control subjects. The marijuana abusers were tested twice: the first evaluation occurred within 72 hours of admission to the inpatient research unit; the second evaluation occurred after 28 to 30 days of monitored abstinence. A three-minute period of EEG was recorded during resting eyes-closed conditions from eight electrodes (F(3), C(3), P(3), O(1), F(4), C(4), P(4), and O(2)). The artifacted EEG was converted to six frequency bands (delta, theta, alpha(1), alpha(2), beta(1), and beta(2)) using a fast Fourier transform. During early abstinence, absolute power was significantly lower (p < 0.05) for the marijuana abusers than for the control subjects for the theta and alpha(1) bands. These reductions in theta and alpha(1) power persisted for 28 days of monitored abstinence. These EEG changes, together with cerebral blood flow deficits, might underlie the cognitive alterations observed in marijuana abusers. Additional research is needed to determine how long these deficits persist during abstinence and if treatment with neuroprotective agents may reverse them. PMID:12853297

  1. [Changes in the Spectral Characteristics of EEG during Neurofeedback Training].

    PubMed

    Kiroy, V N; Lazurenko, D M; Shepelev, I E; Minyaeva, N R; Aslanyan, E V; Bakhtin, O M; Shaposhnikov, D G; Vladimirskiy, B M

    2015-01-01

    We used the ratio of spectral characteristics of the EEG alpha and beta frequencies recorded in 10 apparently healthy subjects (university students) to control a computer cursor in the graphic interface in three scenarios with the use of neurofeedback. Our results showed that the scenario which uses the power of alpha- and beta-2-frequencies provided the highest accuracy and the best speed control. The parameters of beta-1-frequency were found to be less effective since an increase or a decrease of their power could result from an increase or a decrease of the power of alpha- and beta-2-frequencies. However, the subjects got the skill of cursor control with efficiency of 81%, gradually growing during learning, after a relatively short period of time (5 trainings per 2 weeks). PMID:26237948

  2. Discrete Scale Invariance of Human Large EEG Voltage Deflections is More Prominent in Waking than Sleep Stage 2

    PubMed Central

    Zorick, Todd; Mandelkern, Mark A.

    2015-01-01

    Electroencephalography (EEG) is typically viewed through the lens of spectral analysis. Recently, multiple lines of evidence have demonstrated that the underlying neuronal dynamics are characterized by scale-free avalanches. These results suggest that techniques from statistical physics may be used to analyze EEG signals. We utilized a publicly available database of fourteen subjects with waking and sleep stage 2 EEG tracings per subject, and observe that power-law dynamics of critical-state neuronal avalanches are not sufficient to fully describe essential features of EEG signals. We hypothesized that this could reflect the phenomenon of discrete scale invariance (DSI) in EEG large voltage deflections (LVDs) as being more prominent in waking consciousness. We isolated LVDs, and analyzed logarithmically transformed LVD size probability density functions (PDF) to assess for DSI. We find evidence of increased DSI in waking, as opposed to sleep stage 2 consciousness. We also show that the signatures of DSI are specific for EEG LVDs, and not a general feature of fractal simulations with similar statistical properties to EEG. Removing only LVDs from waking EEG produces a reduction in power in the alpha and beta frequency bands. These findings may represent a new insight into the understanding of the cortical dynamics underlying consciousness. PMID:26696860

  3. Discrete Scale Invariance of Human Large EEG Voltage Deflections is More Prominent in Waking than Sleep Stage 2.

    PubMed

    Zorick, Todd; Mandelkern, Mark A

    2015-01-01

    Electroencephalography (EEG) is typically viewed through the lens of spectral analysis. Recently, multiple lines of evidence have demonstrated that the underlying neuronal dynamics are characterized by scale-free avalanches. These results suggest that techniques from statistical physics may be used to analyze EEG signals. We utilized a publicly available database of fourteen subjects with waking and sleep stage 2 EEG tracings per subject, and observe that power-law dynamics of critical-state neuronal avalanches are not sufficient to fully describe essential features of EEG signals. We hypothesized that this could reflect the phenomenon of discrete scale invariance (DSI) in EEG large voltage deflections (LVDs) as being more prominent in waking consciousness. We isolated LVDs, and analyzed logarithmically transformed LVD size probability density functions (PDF) to assess for DSI. We find evidence of increased DSI in waking, as opposed to sleep stage 2 consciousness. We also show that the signatures of DSI are specific for EEG LVDs, and not a general feature of fractal simulations with similar statistical properties to EEG. Removing only LVDs from waking EEG produces a reduction in power in the alpha and beta frequency bands. These findings may represent a new insight into the understanding of the cortical dynamics underlying consciousness. PMID:26696860

  4. EEG signal analysis: a survey.

    PubMed

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

    2010-04-01

    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

  5. Detection of EEG-resting state independent networks by eLORETA-ICA method

    PubMed Central

    Aoki, Yasunori; Ishii, Ryouhei; Pascual-Marqui, Roberto D.; Canuet, Leonides; Ikeda, Shunichiro; Hata, Masahiro; Imajo, Kaoru; Matsuzaki, Haruyasu; Musha, Toshimitsu; Asada, Takashi; Iwase, Masao; Takeda, Masatoshi

    2015-01-01

    Recent functional magnetic resonance imaging (fMRI) studies have shown that functional networks can be extracted even from resting state data, the so called “Resting State independent Networks” (RS-independent-Ns) by applying independent component analysis (ICA). However, compared to fMRI, electroencephalography (EEG) and magnetoencephalography (MEG) have much higher temporal resolution and provide a direct estimation of cortical activity. To date, MEG studies have applied ICA for separate frequency bands only, disregarding cross-frequency couplings. In this study, we aimed to detect EEG-RS-independent-Ns and their interactions in all frequency bands. We applied exact low resolution brain electromagnetic tomography-ICA (eLORETA-ICA) to resting-state EEG data in 80 healthy subjects using five frequency bands (delta, theta, alpha, beta and gamma band) and found five RS-independent-Ns in alpha, beta and gamma frequency bands. Next, taking into account previous neuroimaging findings, five RS-independent-Ns were identified: (1) the visual network in alpha frequency band, (2) dual-process of visual perception network, characterized by a negative correlation between the right ventral visual pathway (VVP) in alpha and beta frequency bands and left posterior dorsal visual pathway (DVP) in alpha frequency band, (3) self-referential processing network, characterized by a negative correlation between the medial prefrontal cortex (mPFC) in beta frequency band and right temporoparietal junction (TPJ) in alpha frequency band, (4) dual-process of memory perception network, functionally related to a negative correlation between the left VVP and the precuneus in alpha frequency band; and (5) sensorimotor network in beta and gamma frequency bands. We selected eLORETA-ICA which has many advantages over the other network visualization methods and overall findings indicate that eLORETA-ICA with EEG data can identify five RS-independent-Ns in their intrinsic frequency bands, and correct correlations within RS-independent-Ns. PMID:25713521

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

    PubMed

    Vakalopoulos, Costa

    2014-01-01

    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 Gαi/o-mediated transduction of inhibitory interneurons. Cognitively, alpha and delta EEG measures are proposed to indicate automatic and flexible strategies, respectively. Sleep is associated with marked changes in relative neuromodulator levels corresponding to EEG markers of distinct stages. Sleep studies on memory consolidation present some of the strongest evidence yet for the respective roles of monoaminergic and cholinergic projections in declarative and non-declarative memory processes, a key theoretical premise for understanding the data. Affective dysregulation is reflected in altered EEG patterns during sleep. PMID:24782698

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

    PubMed Central

    Vakalopoulos, Costa

    2014-01-01

    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 Gαi/o-mediated transduction of inhibitory interneurons. Cognitively, alpha and delta EEG measures are proposed to indicate automatic and flexible strategies, respectively. Sleep is associated with marked changes in relative neuromodulator levels corresponding to EEG markers of distinct stages. Sleep studies on memory consolidation present some of the strongest evidence yet for the respective roles of monoaminergic and cholinergic projections in declarative and non-declarative memory processes, a key theoretical premise for understanding the data. Affective dysregulation is reflected in altered EEG patterns during sleep. PMID:24782698

  8. EEG changes and serum anticholinergic activity measured in patients with delirium in the intensive care unit.

    PubMed

    Plaschke, K; Hill, H; Engelhardt, R; Thomas, C; von Haken, R; Scholz, M; Kopitz, J; Bardenheuer, H J; Weisbrod, M; Weigand, M A

    2007-12-01

    The aim of this study was to examine whether serum anticholinergic activity (SAA) is a reliable indicator of delirium in the ICU, and whether there is a significant correlation between SAA and quantitative electroencephalographic (EEG) data in delirious patients. In a prospective cohort study, we assessed ICU patients diagnosed with delirium (n = 37). EEG measurements and blood analysis including SAA were performed 48 h following ICU admission. The presence of delirium was evaluated using the Confusion Assessment Method for critically ill patients in ICU (CAM-ICU). The SAA level was measured using a competitive radioreceptor binding assay for muscarinergic receptors and quantitative EEG was measured using the CATEEM system. We found that, under comparable conditions, patients in the delirium group showed a higher relative EEG theta power and a reduced alpha power (n = 17) than did the non-delirious patients (n = 20). No difference in measured SAA levels were seen; therefore, there was no correlation between SAA and EEG measurements in delirious patients. We conclude that, in contrast to the EEG, the SAA level cannot be proposed as a tool for diagnosing delirium in ICU patients. PMID:17991256

  9. Can arousing feedback rectify lapses in driving? Prediction from EEG power spectra

    NASA Astrophysics Data System (ADS)

    Lin, Chin-Teng; Huang, Kuan-Chih; Chuang, Chun-Hsiang; Ko, Li-Wei; Jung, Tzyy-Ping

    2013-10-01

    Objective. This study explores the neurophysiological changes, measured using an electroencephalogram (EEG), in response to an arousing warning signal delivered to drowsy drivers, and predicts the efficacy of the feedback based on changes in the EEG. Approach. Eleven healthy subjects participated in sustained-attention driving experiments. The driving task required participants to maintain their cruising position and compensate for randomly induced lane deviations using the steering wheel, while their EEG and driving performance were continuously monitored. The arousing warning signal was delivered to participants who experienced momentary behavioral lapses, failing to respond rapidly to lane-departure events (specifically the reaction time exceeded three times the alert reaction time). Main results. The results of our previous studies revealed that arousing feedback immediately reversed deteriorating driving performance, which was accompanied by concurrent EEG theta- and alpha-power suppression in the bilateral occipital areas. This study further proposes a feedback efficacy assessment system to accurately estimate the efficacy of arousing warning signals delivered to drowsy participants by monitoring the changes in their EEG power spectra immediately thereafter. The classification accuracy was up 77.8% for determining the need for triggering additional warning signals. Significance. The findings of this study, in conjunction with previous studies on EEG correlates of behavioral lapses, might lead to a practical closed-loop system to predict, monitor and rectify behavioral lapses of human operators in attention-critical settings.

  10. Rhythmic activity in EEG and sleep in rats with absence epilepsy.

    PubMed

    Sitnikova, Evgenia; Hramov, Alexander E; Grubov, Vadim; Koronovsky, Alexey A

    2016-01-01

    This study examines the hypothesis that absence epilepsy is accompanied by disturbances of rhythmic activity in EEG during sleep. Sleep-wake architecture and time-frequency parameters of EEG were analyzed during drowsiness and sleep in WAG/Rij rats with genetic predisposition to absence epilepsy. The incidence of seizures varied in a group of 10 rats, in which 5 individuals did not develop epileptic discharges in their EEG (asymptomatic rats). In contrast to asymptomatic, symptomatic subjects (1) displayed less percentage of wakefulness EEG pattern and more non-REM sleep, (2) showed higher beta and less delta EEG power in frontal cortex during non-REM sleep. Mid-frequency oscillations, such as sleep spindles and 5-9Hz oscillations, were detected in EEG automatically and underwent time-frequency analysis by means of skeletons of wavelet surfaces. Some mid-frequency oscillations showed "complex" frequency structure, consisting of the dominant and subdominant components. "Complex" sleep spindles more frequently appeared in asymptomatic rats than in symptomatic, whereas the dominant frequency of these spindles in symptomatic rats was higher than in asymptomatic (12.7 vs 11.9Hz). In general, low-frequency components were readily integrated in sleep spindles in asymptomatic WAG/Rij rats, and decrease in number of "complex" sleep spindles may be associated with epileptic phenotype. PMID:26608255

  11. Use of EEG to track visual attention in two dimensions

    NASA Astrophysics Data System (ADS)

    Coleman, Robert Alan

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

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    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.

  13. Alpha Thalassemia

    MedlinePlus

    Alpha Thalassemia Physicians often mistake alpha thalassemia trait for iron deficiency anemia and incorrectly prescribe iron supplements that have no effect 1 on the anemia. αα αα Normal alpha globin genes ...

  14. Low levels of sarin affect the EEG in marmoset monkeys: a pilot study.

    PubMed

    van Helden, Herman P M; Vanwersch, Raymond A P; Kuijpers, Willem C; Trap, Henk C; Philippens, Ingrid H C; Benschop, Hendrik P

    2004-01-01

    The main purpose of this pilot study was to estimate the lowest observable adverse effect level (LOAEL) for the electroencephalogram (EEG) upon long-term, low-level exposure of vehicle-pretreated and pyridostigmine-pretreated marmoset monkeys to sarin vapour. This is the C.t value (t=5 h) of exposure at which the EEG becomes significantly different from that resulting from air exposure of the same animals. The LOAELs for effects on the EEG in vehicle- and pyridostigmine-pretreated marmosets appeared to be 0.2 and 0.1 mg min m(-3), respectively. Comparatively, the latter LOAEL values are at least an order of magnitude lower than the previously established LOAEL for miosis and only 2-5 times higher than the lowest observable effect level (LOEL) of bound sarin in blood. The second aim of the study was to analyse the EEG of the same marmosets again during a 5-h exposure to air 1 year after exposure to sarin vapour. All the marmosets still demonstrated significant (P <0.05) EEG differences. In most vehicle-pretreated marmosets the energy (microV2) per EEG band was higher than that observed 1 year earlier, which might indicate that neurons had become more sensitive to excitation. This phenomenon was less pronounced in pyridostigmine-pretreated animals. Visual examination of the EEG records revealed clear bursts of alpha frequencies (ca. 9 Hz), resembling sleep-spindles, that were present more frequently in both groups of exposed marmosets than in naive animals. These late changes in spindle oscillation might be the result of changes in the cholinergic system due to exposure to sarin vapour 1 year previously. In conclusion, EEG abnormalities persisting for more than 1 year may occur in humans during long-term (5 h) exposure to subclinical levels of sarin that are not detectable by the currently fielded alarm systems. PMID:15558834

  15. Hypercapnia is a Key Correlate of EEG Activation and Daytime Sleepiness in Hypercapnic Sleep Disordered Breathing Patients

    PubMed Central

    Wang, David; Piper, Amanda J.; Yee, Brendon J.; Wong, Keith K.; Kim, Jong-Won; D'Rozario, Angela; Rowsell, Luke; Dijk, Derk-Jan; Grunstein, Ronald R.

    2014-01-01

    Background: The key determinants of daytime drowsiness in sleep disordered breathing (SDB) are unclear. Hypercapnia has not been examined as a potential contributor due to the lack of reliable measurement during sleep. To overcome this limitation, we studied predominantly hypercapnic SDB patients to investigate the role of hypercapnia on EEG activation and daytime sleepiness. Methods: We measured overnight polysomnography (PSG), arterial blood gases, and Epworth Sleepiness Scale in 55 severe SDB patients with obesity hypoventilation syndrome or overlap syndrome (COPD+ obstructive sleep apnea) before and ∼3 months after positive airway pressure (PAP) treatment. Quantitative EEG analyses were performed, and the Delta/ Alpha ratio was used as an indicator of EEG activation. Results: After the PAP treatment, these patients showed a significant decrease in their waking pCO2, daytime sleepiness, as well as all key breathing/oxygenation parameters during sleep. Overnight Delta/Alpha ratio of EEG was significantly reduced. There is a significant cross-correlation between a reduced wake pCO2, a faster (more activated) sleep EEG (reduced Delta/Alpha ratio) and reduced daytime sleepiness (all p < 0.05) with PAP treatment. Multiple regression analyses showed the degree of change in hypercapnia to be the only significant predictor for both ESS and Delta/ Alpha ratio. Conclusions: Hypercapnia is a key correlate of EEG activation and daytime sleepiness in hypercapnic SDB patients. The relationship between hypercapnia and sleepiness may be mediated by reduced neuro-electrical brain activity. Commentary: A commentary on this article appears in this issue on page 523. Citation: Wang D, Piper AJ, Yee BJ, Wong KK, Kim JW, D'Rozario A, Rowsell L, Dijk DJ, Grunstein RR. Hypercapnia is a key correlate of EEG activation and daytime sleepiness in hypercapnic sleep disordered breathing patients. J Clin Sleep Med 2014;10(5):517-522. PMID:24910553

  16. Effects of Manual Lymph Drainage of the Neck on EEG in Subjects with Psychological Stress

    PubMed Central

    Shim, Jung-Myo; Kim, Sung-Joong

    2014-01-01

    [Purpose] The present study investigated the effect of manual lymph drainage (MLD) of the neck on electroencephalography (EEG) in subjects with psychological stress. [Methods] Twenty-six subjects were randomly allocated to receive one 15-min session of either MLD or resting on a bed (control). [Results] Analysis of EEG in the MLD group showed a significant increase in relaxation, manifested as an increase in average absolute and relative delta and alpha activity. [Conclusion] It is suggested that MLD provides acute neural effects that increase relaxation in subjects with psychological stress. PMID:24567691

  17. EEG-microstate dependent emergence of perceptual awareness

    PubMed Central

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

    2014-01-01

    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

  18. Resting State EEG Hemispheric Power Asymmetry in Children with Dyslexia

    PubMed Central

    Papagiannopoulou, Eleni A.; Lagopoulos, Jim

    2016-01-01

    Dyslexia is a neurodevelopmental disorder estimated to affect between 4 and 7% of the population. It is often referred to as a learning disability and is characterized by deficits in the linguistic system. To better understand the neural underpinnings of dyslexia, we examined the electroencephalography (EEG) power spectra between pre-adolescents with dyslexia and neurotypical control children during eyes closed state. We reported the differences in spontaneous oscillatory activity of each major EEG band (delta, theta, alpha, and beta) adopting a global as well as in a region-by-region and hemispheric approach to elucidate whether there are changes in asymmetry in children with dyslexia compared to controls. We also examined the relationship between EEG power spectra and clinical variables. The findings of our study confirm the presence of an atypical linguistic network, evident in children with dyslexia. This abnormal network hallmarked by a dominance of theta activity suggests that these abnormalities are present prior to these children learning to read, thus implicating delayed maturation and abnormal hypoarousal mechanisms. PMID:26942169

  19. Subtractive Fuzzy Classifier Based Driver Distraction Levels Classification Using EEG

    PubMed Central

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

    2013-01-01

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

  20. Resting State EEG Hemispheric Power Asymmetry in Children with Dyslexia.

    PubMed

    Papagiannopoulou, Eleni A; Lagopoulos, Jim

    2016-01-01

    Dyslexia is a neurodevelopmental disorder estimated to affect between 4 and 7% of the population. It is often referred to as a learning disability and is characterized by deficits in the linguistic system. To better understand the neural underpinnings of dyslexia, we examined the electroencephalography (EEG) power spectra between pre-adolescents with dyslexia and neurotypical control children during eyes closed state. We reported the differences in spontaneous oscillatory activity of each major EEG band (delta, theta, alpha, and beta) adopting a global as well as in a region-by-region and hemispheric approach to elucidate whether there are changes in asymmetry in children with dyslexia compared to controls. We also examined the relationship between EEG power spectra and clinical variables. The findings of our study confirm the presence of an atypical linguistic network, evident in children with dyslexia. This abnormal network hallmarked by a dominance of theta activity suggests that these abnormalities are present prior to these children learning to read, thus implicating delayed maturation and abnormal hypoarousal mechanisms. PMID:26942169

  1. EEG-MEG Integration Enhances the Characterization of Functional and Effective Connectivity in the Resting State Network

    PubMed Central

    Mideksa, Kidist Gebremariam; Anwar, Abdul Rauf; Stephani, Ulrich; Deuschl, Günther; Freitag, Christine M.; Siniatchkin, Michael

    2015-01-01

    At the sensor level many aspects, such as spectral power, functional and effective connectivity as well as relative-power-ratio ratio (RPR) and spatial resolution have been comprehensively investigated through both electroencephalography (EEG) and magnetoencephalography (MEG). Despite this, differences between both modalities have not yet been systematically studied by direct comparison. It remains an open question as to whether the integration of EEG and MEG data would improve the information obtained from the above mentioned parameters. Here, EEG (64-channel system) and MEG (275 sensor system) were recorded simultaneously in conditions with eyes open (EO) and eyes closed (EC) in 29 healthy adults. Spectral power, functional and effective connectivity, RPR, and spatial resolution were analyzed at five different frequency bands (delta, theta, alpha, beta and gamma). Networks of functional and effective connectivity were described using a spatial filter approach called the dynamic imaging of coherent sources (DICS) followed by the renormalized partial directed coherence (RPDC). Absolute mean power at the sensor level was significantly higher in EEG than in MEG data in both EO and EC conditions. At the source level, there was a trend towards a better performance of the combined EEG+MEG analysis compared with separate EEG or MEG analyses for the source mean power, functional correlation, effective connectivity for both EO and EC. The network of coherent sources and the spatial resolution were similar for both the EEG and MEG data if they were analyzed separately. Results indicate that the combined approach has several advantages over the separate analyses of both EEG and MEG. Moreover, by a direct comparison of EEG and MEG, EEG was characterized by significantly higher values in all measured parameters in both sensor and source level. All the above conclusions are specific to the resting state task and the specific analysis used in this study to have general conclusion multi-center studies would be helpful. PMID:26509448

  2. Effects of nootropics on the EEG in conscious rats and their modification by glutamatergic inhibitors.

    PubMed

    Vorobyov, Vasily; Kaptsov, Vladimir; Kovalev, Georgy; Sengpiel, Frank

    2011-05-30

    To study the effects of acute and repeated injections of nootropics and to learn how glutamate receptors might be involved in their mediation, the frequency spectra of cortical and hippocampal electroencephalogram (EEG) were analyzed in non-narcotized rats subcutaneously injected repeatedly with Piracetam (400mg/kg) or its analogue, Noopept (0.2mg/kg), after intracerebroventricular infusions of saline (5 ?l) or the antagonists of NMDA and quisqualate/AMPA receptors: CPP (0.1 nmol) and GDEE (1 ?mol), respectively. Piracetam increased alpha/beta1 EEG activity in the left frontal cortex, and alpha activity in both the right cortex and hippocampus, with a 10-min latency and 40-min duration. Noopept increased alpha/beta1 activity, with 30-min latency and 40-min duration in all brain areas. CPP pretreatment eliminated Piracetam EEG effects; reduced Noopept effects in the cortex and completely suppressed them in the hippocampus. After four injections of Piracetam, EEG effects were very small in the cortex, and completely lacking in the hippocampus, while GDEE pretreatment partially recovered them. The effect of Noopept in the alpha/beta1 ranges was replaced by increased beta2 activity after the eighth injection, while no effects were observed after the ninth one. GDEE pretreatment restored the effect of Noopept in the beta2 frequency range. These results demonstrate similarities in EEG effects and their mediatory mechanisms for Piracetam and its much more effective analogue, Noopept. Activation of NMDA receptors is involved in the effects of a single injection of the nootropics, whereas activation of quisqualate/AMPA receptors is associated with the decrease in their efficacy after repeated use. PMID:21414388

  3. Changes preceding interictal epileptic EEG abnormalities: Comparison between EEG/fMRI and intracerebral EEG

    PubMed Central

    Pittau, Francesca; LeVan, Pierre; Moeller, Friederike; Gholipour, Taha; Haegelen, Claire; Zelmann, Rina; Dubeau, François; Gotman, Jean

    2013-01-01

    Summary Purpose In simultaneous scalp electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), blood oxygen level dependent (BOLD) changes occurring before the spike have been sometimes described but could not be explained. To characterize the origin of this prespike BOLD signal change, we looked for electrographic changes in stereo-EEG (SEEG) possibly preceding the scalp spike in patients that showed early BOLD response in EEG/fMRI. Methods We studied four patients with drug-resistant focal epilepsy who underwent EEG/fMRI, showed a pres-pike BOLD response, and were then studied with depth electrodes for presurgical localization of the epileptic generator. Early BOLD responses in the region of the spike field were analyzed using models with hemodynamic response functions (HRFs) peaking from −9 to +9 s around the spike. SEEG recordings in the period and location corresponding to the early HRF responses were analyzed to detect if electrographic changes were present in the SEEG before the scalp abnormality. Key Findings One of the four patients presented a SEEG interictal discharge in the period corresponding to the early BOLD response. In the other three, no electrographic changes were detected in the SEEG in the period corresponding to early BOLD changes. Significance Although the early BOLD activity may sometimes be explained by a synchronized neural discharge detectable with SEEG but not visible on the scalp EEG, in most cases the early BOLD response reflects a metabolic phenomenon that does not appear to result from a synchronized neuronal discharge. Prespike metabolic responses can result from synchronized or nonsynchronized neuronal activity, or from nonneuronal mechanisms including glia. PMID:21671923

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

    PubMed

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

    2014-03-01

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

  5. Genetics Home Reference: mucolipidosis III alpha/beta

    MedlinePlus

    ... Simensen RJ, Kudo M, Stevenson RE, Friez MJ. Phenotype and genotype in mucolipidoses II and III alpha/ ... mutation analysis of 40 Japanese patients showed genotype-phenotype correlation. J Hum Genet. 2009 Mar;54(3): ...

  6. Multimodal EEG Recordings, Psychometrics and Behavioural Analysis.

    PubMed

    Boeijinga, Peter H

    2015-01-01

    High spatial and temporal resolution measurements of neuronal activity are preferably combined. In an overview on how this approach can take shape, multimodal electroencephalography (EEG) is treated in 2 main parts: by experiments without a task and in the experimentally cued working brain. It concentrates first on the alpha rhythm properties and next on data-driven search for patterns such as the default mode network. The high-resolution volumic distributions of neuronal metabolic indices result in distributed cortical regions and possibly relate to numerous nuclei, observable in a non-invasive manner in the central nervous system of humans. The second part deals with paradigms in which nowadays assessment of target-related networks can align level-dependent blood oxygenation, electrical responses and behaviour, taking the temporal resolution advantages of event-related potentials. Evidence-based electrical propagation in serial tasks during performance is now to a large extent attributed to interconnected pathways, particularly chronometry-dependent ones, throughout a chain including a dorsal stream, next ventral cortical areas taking the flow of information towards inferior temporal domains. The influence of aging is documented, and results of the first multimodal studies in neuropharmacology are consistent. Finally a scope on implementation of advanced clinical applications and personalized marker strategies in neuropsychiatry is indicated. PMID:26901154

  7. Sound fields in biosphere of the mountain streams and their influence on the human EEG

    NASA Astrophysics Data System (ADS)

    Kasprzak, Cezary; Damijan, Zbigniew; Panuszka, Ryszard

    2001-05-01

    Low-frequency acoustics fields in the biosphere of the headwater regions in Poland (Bieszczady Mountains and Tatry Mountains) were researched and the the influence of observed low-frequency acoustics field on changes of human EEG signals was analyzed. Several places were found with specific distribution of sound fields where low frequencies dominated. Interesting parameters of distribution of the riverbeds and physical characterization of flows were determined. Standard EEG signal was recorded from subjects until exposure for 20 min. It was ascertained that spectra of sound-pressure levels were with specific shape, very similar for a group of rivers. The influences of SPL on level of power spectrum of EEG signal were analyzed. Changes in the brain waves were observed with increases in delta and decreases in alpha. Tested subjects reported behavior specific for relaxation.

  8. Improvements in quantitative EEG following consumption of a natural citicoline-enhanced beverage.

    PubMed

    Bruce, Steven E

    2012-06-01

    The present study examined the impact of a taurine-free drink enhanced with citicoline and other natural ingredients on electrophysiological markers of mental alertness. Ten healthy adult participants enrolled in a double-blind, placebo-controlled crossover study and were randomized to receive either placebo or the citicoline supplement on the first visit. Measures of electrical brain activity using electroencephalogram (EEG) were collected 30 min after consuming the beverage. Seven days after the initial assessment participants completed the alternative condition (placebo or citicoline beverage). Compared to placebo, significant improvements were found in frontal alpha EEG and N100 event related potentials (ERP) associated with the citicoline-enhanced supplement. These preliminary findings suggest that a novel brain drink containing compounds known to increase choline in the brain significantly improved attention as measured by ERP and EEG. These findings suggest that a viable and alternative brain supplement without potential compounds such as taurine may augment attentional mechanisms in healthy individuals. PMID:22578105

  9. Eye contact reveals a relationship between Neuroticism and anterior EEG asymmetry.

    PubMed

    Uusberg, Helen; Allik, Jüri; Hietanen, Jari K

    2015-07-01

    Although anterior functional brain asymmetry has been linked to individual differences in affect and motivation, its relations with the Five Factor Model personality traits remain unclear. We investigated anterior EEG alpha-activity asymmetry in response to variable degrees of social contact induced by different gaze directions of a "live" model. Neuroticism was negatively related to the anterior EEG asymmetry scores in response to direct gaze, indicating that higher levels of Neuroticism were associated with avoidance-related, relative right-sided functional brain asymmetry. Neuroticism was also related to behavioral direct gaze avoidance and subjective averted gaze preference. These relationships arose primarily from the Withdrawal aspect factor, suggesting that two subdomains of Neuroticism may be differentially related to approach-avoidance tendencies. These findings demonstrate that experimental manipulations of social contact can reveal personality related differences in anterior EEG asymmetry responsiveness, offering a motivationally salient alternative to resting state measures. PMID:25980386

  10. Artifact: recording EEG in special care units.

    PubMed

    Tatum, William O; Dworetzky, Barbara A; Freeman, W David; Schomer, Donald L

    2011-06-01

    Artifacts may be obtained during routine recording but are more common in special care units (SCUs) outside of the EEG laboratory, where complex electrical currents are present that create a "hostile" environment. Special care units include the epilepsy monitoring unit, neurologic intensive care unit, and operating room, where artifact is present in virtually every recording, increasing with prolonged use. Nonepileptic attacks treated as epileptic seizures have been incorrectly diagnosed and treated due to a misinterpreted EEG. The recent emergence of continuous EEG as a neurophysiologic surrogate for brain function in the neurologic intensive care unit and operating room has also brought a greater amount and new types of EEG artifact. The artifacts encountered in special care units during continuous EEG are becoming more complex and may have adverse therapeutic implications. Our knowledge of artifact needs to parallel our growth in technology to avoid the pitfalls that may be incurred during visual analysis of the EEG. PMID:21633252

  11. On the Individuality of Sleep EEG Spectra

    PubMed Central

    Lewandowski, Achim; Rosipal, Roman; Dorffner, Georg

    2013-01-01

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

  12. Use of EEG to Diagnose ADHD

    PubMed Central

    Lenartowicz, Agatha; Loo, Sandra K.

    2015-01-01

    Electroencephalography (EEG) has, historically, played a focal role in the assessment of neural function in children with attention deficit hyperactivity disorder (ADHD). We review here the most recent developments in the utility of EEG in the diagnosis of ADHD, with emphasis on the most commonly used and emerging EEG metrics and their reliability in diagnostic classification. Considering the clinical heterogeneity of ADHD and the complexity of information available from the EEG signals, we suggest that considerable benefits are to be gained from multivariate analyses and a focus towards understanding of the neural generators of EEG. We conclude that while EEG cannot currently be used as a diagnostic tool, vast developments in analytical and technological tools in its domain anticipate future progress in its utility in the clinical setting. PMID:25234074

  13. Aesthetic preference recognition of 3D shapes using EEG.

    PubMed

    Chew, Lin Hou; Teo, Jason; Mountstephens, James

    2016-04-01

    Recognition and identification of aesthetic preference is indispensable in industrial design. Humans tend to pursue products with aesthetic values and make buying decisions based on their aesthetic preferences. The existence of neuromarketing is to understand consumer responses toward marketing stimuli by using imaging techniques and recognition of physiological parameters. Numerous studies have been done to understand the relationship between human, art and aesthetics. In this paper, we present a novel preference-based measurement of user aesthetics using electroencephalogram (EEG) signals for virtual 3D shapes with motion. The 3D shapes are designed to appear like bracelets, which is generated by using the Gielis superformula. EEG signals were collected by using a medical grade device, the B-Alert X10 from advance brain monitoring, with a sampling frequency of 256 Hz and resolution of 16 bits. The signals obtained when viewing 3D bracelet shapes were decomposed into alpha, beta, theta, gamma and delta rhythm by using time-frequency analysis, then classified into two classes, namely like and dislike by using support vector machines and K-nearest neighbors (KNN) classifiers respectively. Classification accuracy of up to 80 % was obtained by using KNN with the alpha, theta and delta rhythms as the features extracted from frontal channels, Fz, F3 and F4 to classify two classes, like and dislike. PMID:27066153

  14. [Topographic-quantitative EEG-analysis of the paradoxical arousal reaction. EEG changes during urologic surgery using isoflurane/ N2O anesthesia].

    PubMed

    Bischoff, P; Kochs, E; Droese, D; Meyer-Moldenhauer, W H; Schulte am Esch, J

    1993-03-01

    Increases in slow-wave (delta) activity in the EEG may reflect increased depth of anaesthesia provided that hypoxia, haemodynamic instability and drug overdose have been excluded. In contrast, similar intraoperative EEG responses have been described as paradoxical arousal reactions. The aim of this study was to assess the effects of surgical stimulation on spatial EEG changes during anaesthesia with 0.6% isoflurane/66% nitrous oxide. METHODS. The present study investigated changes in EEG power and frequencies in 20 patients (mean age 36 +/- 8 years; ASA I or II) scheduled for elective urological surgery during steady-state anaesthesia with 0.6% isoflurane and 66% nitrous oxide. The following variables were measured: heart rate (HR), mean arterial blood pressure (MAP), end-tidal isoflurane (PetISO) and carbon dioxide concentrations (PetCO2), arterial oxygen saturation (SaO2%) and body temperature (degree C). Patients were randomly assigned to one of two groups: group 1 (n = 10; without surgery) and group 2 (n = 10; with surgical procedure). The EEG was recorded over 20 min. The first 5 min were taken as baseline. In group 2 surgical stimulation (skin incision with subsequent surgical preparation) was started 1-2 min after recording of baseline values. Topographical distribution of EEG output was recorded from 17 electrodes (international 10-20 system), digitized and stored on disk (CATEEM) after establishment of steady-state anaesthesia (PetISO: 0.6%; PetCO2: 35-37 mmHg). Data are given as medium (microV2/Hz) and relative changes (%) +/- SD with respect to baseline. Statistical significance was tested for F4 versus C4 for the delta- and alpha-1-frequency bands using Wilcoxon's test (P < 0.05). RESULTS. In group 1 (without surgical stimulation) all parameters did not change over time. EEG slowing with an increase in power (> 100%) was noted in 8 patients of group 2 (n = 10; during surgical stimulation). By visual inspection of the original EEG tracings paradoxical arousal patterns were seen in these patients. In group 2, delta output changed from 69.6 microV2/Hz (baseline) to 147.4 microV2/Hz at frontal leads (F4) 5-6 min after the start of surgery. Only minimal changes were observed for theta activity. At the same time, in most cases fast wave activity (alpha 1, alpha 2, beta 1 and beta 2) was decreased by more than 50% at identical cortical areas. Increases in MAP were noted continuously after start of surgery up to a maximum of 19.8% from baseline, which became significant at the 16-min level. Heart rate did not change over time. DISCUSSION. Our data demonstrate that EEG slowing may be induced by surgical stimulation during steady-state anaesthesia with 0.6% isoflurane/66% nitrous oxide in oxygen. These findings are consistent with previous reports indicating the occurrence of slow wave patterns following sensory stimulation in comatose patients. Since these events occur predominantly at frontal areas they may not be detected with single-channel parietal recordings. Our data suggest that topographical EEG monitoring may useful for assessing painful events during surgery. Using EEG monoparameters like spectral edge frequency or median the occurrence of paradoxical arousal reactions may be falsely interpreted as an increased depth of anaesthesia. PMID:8480900

  15. Age-dependent electroencephalogram (EEG) patterns during sevoflurane general anesthesia in infants.

    PubMed

    Cornelissen, Laura; Kim, Seong-Eun; Purdon, Patrick L; Brown, Emery N; Berde, Charles B

    2015-01-01

    Electroencephalogram (EEG) approaches may provide important information about developmental changes in brain-state dynamics during general anesthesia. We used multi-electrode EEG, analyzed with multitaper spectral methods and video recording of body movement to characterize the spatio-temporal dynamics of brain activity in 36 infants 0-6 months old when awake, and during maintenance of and emergence from sevoflurane general anesthesia. During maintenance: (1) slow-delta oscillations were present in all ages; (2) theta and alpha oscillations emerged around 4 months; (3) unlike adults, all infants lacked frontal alpha predominance and coherence. Alpha power was greatest during maintenance, compared to awake and emergence in infants at 4-6 months. During emergence, theta and alpha power decreased with decreasing sevoflurane concentration in infants at 4-6 months. These EEG dynamic differences are likely due to developmental factors including regional differences in synaptogenesis, glucose metabolism, and myelination across the cortex. We demonstrate the need to apply age-adjusted analytic approaches to develop neurophysiologic-based strategies for pediatric anesthetic state monitoring. PMID:26102526

  16. Age effects on EEG correlates of the Wisconsin Card Sorting Test

    PubMed Central

    Dias, Nuno S; Ferreira, Daniela; Reis, Joana; Jacinto, Luís R; Fernandes, Luís; Pinho, Francisco; Festa, Joana; Pereira, Mariana; Afonso, Nuno; Santos, Nadine C; Cerqueira, João J; Sousa, Nuno

    2015-01-01

    Body and brain undergo several changes with aging. One of the domains in which these changes are more remarkable relates with cognitive performance. In the present work, electroencephalogram (EEG) markers (power spectral density and spectral coherence) of age-related cognitive decline were sought whilst the subjects performed the Wisconsin Card Sorting Test (WCST). Considering the expected age-related cognitive deficits, WCST was applied to young, mid-age and elderly participants, and the theta and alpha frequency bands were analyzed. From the results herein presented, higher theta and alpha power were found to be associated with a good performance in the WCST of younger subjects. Additionally, higher theta and alpha coherence were also associated with good performance and were shown to decline with age and a decrease in alpha peak frequency seems to be associated with aging. Additionally, inter-hemispheric long-range coherences and parietal theta power were identified as age-independent EEG correlates of cognitive performance. In summary, these data reveals age-dependent as well as age-independent EEG correlates of cognitive performance that contribute to the understanding of brain aging and related cognitive deficits. PMID:26216431

  17. Indicators of sleepiness in an ambulatory EEG study of night driving.

    PubMed

    Papadelis, Christos; Kourtidou-Papadeli, Chrysoula; Bamidis, Panagiotis D; Chouvarda, Ioanna; Koufogiannis, D; Bekiaris, E; Maglaveras, Nikos

    2006-01-01

    Driver sleepiness due to sleep deprivation is a causative factor in 1% to 3% of all motor vehicle crashes. In recent studies, the importance of developing driver fatigue countermeasure devices has been stressed, in order to help prevent driving accidents and errors. Although numerous physiological indicators are available to describe an individual's level of alertness, the EEG signal has been shown to be one of the most predictive and reliable, since it is a direct measure of brain activity. In the present study, multichannel EEG data that were collected from 20 sleep-deprived subjects during real environmental conditions of driving are presented for the first time. EEG data's annotation made by two independent Medical Doctors revealed an increase of slowing activity and an acute increase of the alpha waves 5-10 seconds before driving events. From the EEG data that were collected, the Relative Band Ratio (RBR) of the EEG frequency bands, the Shannon Entropy, and the Kullback-Leibler (KL) Entropy were estimated for each one second segment. The mean values of these measurements were estimated for 5 minutes periods. Analysis revealed a significant increase of alpha waves relevant band ratios (RBR), a decrease of gamma waves RBR, and a significant decrease of KL entropy when the first and the last 5-min periods were compared. A rapid decrease of both Shannon and K-L entropies was observed just before the driving events. Conclusively, EEG can assess effectively the brain activity alterations that occur a few seconds before sleeping/drowsiness events in driving, and its quantitative measurements can be used as potential sleepiness indicators for future development of driver fatigue countermeasure devices. PMID:17946748

  18. Resting State EEG in Children With Learning Disabilities: An Independent Component Analysis Approach.

    PubMed

    Jäncke, Lutz; Alahmadi, Nsreen

    2016-01-01

    In this study, the neurophysiological underpinnings of learning disabilities (LD) in children are examined using resting state EEG. We were particularly interested in the neurophysiological differences between children with learning disabilities not otherwise specified (LD-NOS), learning disabilities with verbal disabilities (LD-Verbal), and healthy control (HC) children. We applied 2 different approaches to examine the differences between the different groups. First, we calculated theta/beta and theta/alpha ratios in order to quantify the relationship between slow and fast EEG oscillations. Second, we used a recently developed method for analyzing spectral EEG, namely the group independent component analysis (gICA) model. Using these measures, we identified substantial differences between LD and HC children and between LD-NOS and LD-Verbal children in terms of their spectral EEG profiles. We obtained the following findings: (a) theta/beta and theta/alpha ratios were substantially larger in LD than in HC children, with no difference between LD-NOS and LD-Verbal children; (b) there was substantial slowing of EEG oscillations, especially for gICs located in frontal scalp positions, with LD-NOS children demonstrating the strongest slowing; (c) the estimated intracortical sources of these gICs were mostly located in brain areas involved in the control of executive functions, attention, planning, and language; and (d) the LD-Verbal children demonstrated substantial differences in EEG oscillations compared with LD-NOS children, and these differences were localized in language-related brain areas. The general pattern of atypical neurophysiological activation found in LD children suggests that they suffer from neurophysiological dysfunction in brain areas involved with the control of attention, executive functions, planning, and language functions. LD-Verbal children also demonstrate atypical activation, especially in language-related brain areas. These atypical neurophysiological activation patterns might provide a helpful guide for rehabilitation strategies to treat the deficiencies in these children with LD. PMID:26545819

  19. EEG Differences Between the Combined and Inattentive Types of Attention-Deficit/Hyperactivity Disorder in Girls: A Further Investigation.

    PubMed

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

    2013-10-16

    This study further investigated electroencephalogram (EEG) differences between girls with the Combined and Inattentive types of attention-deficit/hyperactivity disorder (AD/HD). We selected subjects with widely separated scores on hyperactivity-impulsivity symptoms to behaviorally exaggerate diagnostic group differences. Twenty girls with AD/HD Combined type, 20 girls with AD/HD Inattentive type, and 20 controls (aged 7-12 years) had an eyes-closed resting EEG recorded from 19 electrodes. The EEG was fast Fourier transformed, and estimates for total power, absolute and relative power in the delta, theta, alpha, and beta frequency bands, and the theta/beta ratio were calculated and analyzed in 9 scalp regions. Girls of the Combined type, compared with girls of the Inattentive type, had elevated midline total power, elevated temporal absolute alpha activity, elevated posterior absolute beta activity, reduced right hemisphere relative delta and reduced left hemisphere relative alpha activity, and reduced theta/beta ratio in the left hemisphere. Although topographic differences were again found between the AD/HD types, significant global differences remain elusive in the EEGs of girls with the Combined and Inattentive types. Despite creating behaviorally exaggerated AD/HD type groups, girls' EEG activity failed to replicate differences found previously in mixed-sex groups. The EEG profiles of AD/HD types in girls are markedly different from those found in boys. This reinforces the notion that it is no longer appropriate to apply the male-based literature to all AD/HD groups; rather, the use of single-sex subject groups is necessary in EEG research of AD/HD. PMID:24131620

  20. Modafinil Increases Awake EEG Activation and Improves Performance in Obstructive Sleep Apnea during Continuous Positive Airway Pressure Withdrawal

    PubMed Central

    Wang, David; Bai, Xiao Xue; Williams, Shaun C.; Hua, Shu Cheng; Kim, Jong-Won; Marshall, Nathaniel S.; D'Rozario, Angela; Grunstein, Ronald R.

    2015-01-01

    Objectives: We examined the changes in waking electroencephalography (EEG) biomarkers with modafinil during continuous positive airway pressure (CPAP) withdrawal in patients with obstructive sleep apnea (OSA) to investigate neurophysiological evidence for potential neurocognitive improvements. Design: Randomized double-blind placebo-controlled crossover study. CPAP was used for the first night and then withdrawn for 2 subsequent nights. Each morning after the 2 CPAP withdrawal nights, patients received either 200 mg modafinil or placebo. After a 5-w washout, the procedure repeated with the crossover drug. Setting: University teaching hospital. Participants: Stable CPAP users (n = 23 men with OSA) Measurement and Results: Karolinska Drowsiness Test (KDT) (awake EEG measurement with eyes open and closed), Psychomotor Vigilance Task (PVT), and driving simulator Performance were assessed bihourly during the 3 testing days following CPAP treatment and CPAP withdrawal nights. Compared to placebo, modafinil significantly increased awake EEG activation (faster EEG frequency) with increased alpha/delta (A/D) ratio (P < 0.0001) and fast ratio = (alpha+beta)/(delta+theta) (P < 0.0001) across the 2 days of CPAP withdrawal. The A/D ratio significantly correlated with the driving simulator response time (P = 0.015), steering variation (P = 0.002), and PVT reaction time (P = 0.006). In contrast, individual EEG band power of alpha, beta, theta, and delta did not correlate with any neurocognitive performance. Conclusions: Modafinil administration during continuous positive airway pressure (CPAP) withdrawal increased awake EEG activation, which correlated to improved performance. This study provides supporting neurophysiological evidence that modafinil is a potential short-term treatment option during acute CPAP withdrawal. Citation: Wang D, Bai XX, Williams SC, Hua SC, Kim JW, Marshall NS, D'Rozario A, Grunstein RR. Modafinil increases awake EEG activation and improves performance in obstructive sleep apnea during continuous positive airway pressure withdrawal. SLEEP 2015;38(8):1297–1303. PMID:26158894

  1. 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)

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

    2011-01-01

    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.

  2. Modeling the contribution of lamina 5 neuronal and network dynamics to low frequency EEG phenomena.

    PubMed

    Karameh, Fadi N; Dahleh, Munther A; Brown, Emery N; Massaquoi, Steve G

    2006-10-01

    The Electroencephalogram (EEG) is an important clinical and research tool in neurophysiology. With the advent of recording techniques, new evidence is emerging on the neuronal populations and wiring in the neocortex. A main challenge is to relate the EEG generation mechanisms to the underlying circuitry of the neocortex. In this paper, we look at the principal intrinsic properties of neocortical cells in layer 5 and their network behavior in simplified simulation models to explain the emergence of several important EEG phenomena such as the alpha rhythms, slow-wave sleep oscillations, and a form of cortical seizure. The models also predict the ability of layer 5 cells to produce a resonance-like neuronal recruitment known as the augmenting response. While previous models point to deeper brain structures, such as the thalamus, as the origin of many EEG rhythms (spindles), the current model suggests that the cortical circuitry itself has intrinsic oscillatory dynamics which could account for a wide variety of EEG phenomena. PMID:16897093

  3. EEG and ocular correlates of circadian melatonin phase and human performance decrements during sleep loss

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

    The aim of this study was to quantify the associations between slow eye movements (SEMs), eye blink rate, waking electroencephalogram (EEG) power density, neurobehavioral performance, and the circadian rhythm of plasma melatonin in a cohort of 10 healthy men during up to 32 h of sustained wakefulness. The time course of neurobehavioral performance was characterized by fairly stable levels throughout the first 16 h of wakefulness followed by deterioration during the phase of melatonin secretion. This deterioration was closely associated with an increase in SEMs. Frontal low-frequency EEG activity (1-7 Hz) exhibited a prominent increase with time awake and little circadian modulation. EEG alpha activity exhibited circadian modulation. The dynamics of SEMs and EEG activity were phase locked to changes in neurobehavioral performance and lagged the plasma melatonin rhythm. The data indicate that frontal areas of the brain are more susceptible to sleep loss than occipital areas. Frontal EEG activity and ocular parameters may be used to monitor and predict changes in neurobehavioral performance associated with sleep loss and circadian misalignment.

  4. Decomposing EEG data into space-time-frequency components using Parallel Factor Analysis.

    PubMed

    Miwakeichi, Fumikazu; Martínez-Montes, Eduardo; Valdés-Sosa, Pedro A; Nishiyama, Nobuaki; Mizuhara, Hiroaki; Yamaguchi, Yoko

    2004-07-01

    Finding the means to efficiently summarize electroencephalographic data has been a long-standing problem in electrophysiology. A popular approach is identification of component modes on the basis of the time-varying spectrum of multichannel EEG recordings--in other words, a space/frequency/time atomic decomposition of the time-varying EEG spectrum. Previous work has been limited to only two of these dimensions. Principal Component Analysis (PCA) and Independent Component Analysis (ICA) have been used to create space/time decompositions; suffering an inherent lack of uniqueness that is overcome only by imposing constraints of orthogonality or independence of atoms. Conventional frequency/time decompositions ignore the spatial aspects of the EEG. Framing of the data being as a three-way array indexed by channel, frequency, and time allows the application of a unique decomposition that is known as Parallel Factor Analysis (PARAFAC). Each atom is the tri-linear decomposition into a spatial, spectral, and temporal signature. We applied this decomposition to the EEG recordings of five subjects during the resting state and during mental arithmetic. Common to all subjects were two atoms with spectral signatures whose peaks were in the theta and alpha range. These signatures were modulated by physiological state, increasing during the resting stage for alpha and during mental arithmetic for theta. Furthermore, we describe a new method (Source Spectra Imaging or SSI) to estimate the location of electric current sources from the EEG spectrum. The topography of the theta atom is frontal and the maximum of the corresponding SSI solution is in the anterior frontal cortex. The topography of the alpha atom is occipital with maximum of the SSI solution in the visual cortex. We show that the proposed decomposition can be used to search for activity with a given spectral and topographic profile in new recordings, and that the method may be useful for artifact recognition and removal. PMID:15219576

  5. Phenotyping Bleeding

    PubMed Central

    James, Paula; Coller, Barry S.

    2013-01-01

    Purpose of review Although recorded evidence of phenotyping bleeding disorders extends back two millennia, standardization of phenotyping has only begun in the past half century. This was spurred by the need for greater precision in diagnosing disorders in order to select proper laboratory tests and treatment, and the realization that the bleeding history provides prognostic information about the future risk of bleeding with surgery or invasive procedures. Recent findings New bleeding assessment tools (BATs) have been developed to: 1. evaluate the relative bleeding risks associated with new anticoagulants and antiplatelet agents, 2. assess the efficacy of new thrombopoiesis stimulating agents in preventing hemorrhage in patients with immune thrombocytopenia, and 3. assess complex gene-gene and gene-environment interactions. New web-based systems allow many researchers to collaborate by sharing the same electronic phenotyping infrastructure. Major issues of validation remain, but at present, the data indicate that the new BATs have relatively high negative predictive value for excluding a significant bleeding disorder, but disappointingly low positive predictive values. Summary New instruments to phenotype bleeding have been developed to address a number of different important clinical and research goals. The improved standardization and opportunities for collaborative studies hold promise for maximizing diagnostic, prognostic, and scientific information. PMID:22759628

  6. EEG Changes Due to Experimentally Induced 3G Mobile Phone Radiation.

    PubMed

    Roggeveen, Suzanne; van Os, Jim; Viechtbauer, Wolfgang; Lousberg, Richel

    2015-01-01

    The aim of this study was to investigate whether a 15-minute placement of a 3G dialing mobile phone causes direct changes in EEG activity compared to the placement of a sham phone. Furthermore, it was investigated whether placement of the mobile phone on the ear or the heart would result in different outcomes. Thirty-one healthy females participated. All subjects were measured twice: on one of the two days the mobile phone was attached to the ear, the other day to the chest. In this single-blind, cross-over design, assessments in the sham phone condition were conducted directly preceding and following the mobile phone exposure. During each assessment, EEG activity and radiofrequency radiation were recorded jointly. Delta, theta, alpha, slowbeta, fastbeta, and gamma activity was computed. The association between radiation exposure and the EEG was tested using multilevel random regression analyses with radiation as predictor of main interest. Significant radiation effects were found for the alpha, slowbeta, fastbeta, and gamma bands. When analyzed separately, ear location of the phone was associated with significant results, while chest placement was not. The results support the notion that EEG alterations are associated with mobile phone usage and that the effect is dependent on site of placement. Further studies are required to demonstrate the physiological relevance of these findings. PMID:26053854

  7. Measurement of neural signals from inexpensive, wireless and dry EEG systems.

    PubMed

    Grummett, T S; Leibbrandt, R E; Lewis, T W; DeLosAngeles, D; Powers, D M W; Willoughby, J O; Pope, K J; Fitzgibbon, S P

    2015-07-01

    Electroencephalography (EEG) is challenged by high cost, immobility of equipment and the use of inconvenient conductive gels. We compared EEG recordings obtained from three systems that are inexpensive, wireless, and/or dry (no gel), against recordings made with a traditional, research-grade EEG system, in order to investigate the ability of these 'non-traditional' systems to produce recordings of comparable quality to a research-grade system. The systems compared were: Emotiv EPOC (inexpensive and wireless), B-Alert (wireless), g.Sahara (dry) and g.HIamp (research-grade). We compared the ability of the systems to demonstrate five well-studied neural phenomena: (1) enhanced alpha activity with eyes closed versus open; (2) visual steady-state response (VSSR); (3) mismatch negativity; (4) P300; and (5) event-related desynchronization/synchronization. All systems measured significant alpha augmentation with eye closure, and were able to measure VSSRs (although these were smaller with g.Sahara). The B-Alert and g.Sahara were able to measure the three time-locked phenomena equivalently to the g.HIamp. The Emotiv EPOC did not have suitably located electrodes for two of the tasks and synchronization considerations meant that data from the time-locked tasks were not assessed. The results show that inexpensive, wireless, or dry systems may be suitable for experimental studies using EEG, depending on the research paradigm, and within the constraints imposed by their limited electrode placement and number. PMID:26020164

  8. Coherence in resting-state EEG as a predictor for the recovery from unresponsive wakefulness syndrome.

    PubMed

    Schorr, Barbara; Schlee, Winfried; Arndt, Marion; Bender, Andreas

    2016-05-01

    We investigated differences of EEG coherence within (short-range), and between (long-range) specified brain areas as diagnostic markers for different states in disorders of consciousness (DOC), and their predictive value for recovery from unresponsive wakefulness syndrome (UWS). EEGs of 73 patients and 24 controls were recorded and coma recovery scale- revised (CRS-R) scores were assessed. CRS-R of UWS patients was collected after 12 months and divided into two groups (improved/unimproved). Frontal, parietal, fronto-parietal, fronto-temporal, and fronto-occipital coherence was computed, as well as EEG power over frontal, parietal, occipital, and temporal areas. Minimally conscious patients (MCS) and UWS patients could not be differentiated based on their coherence patterns or on EEG power. Fronto-parietal and parietal coherence could positively predict improvement of UWS patients, i.e. recovery from UWS to MCS. Parietal coherence was significantly higher in delta and theta frequencies in the improved group, as well as the coherence between frontal and parietal regions in delta, theta, alpha, and beta frequencies. High parietal delta and theta, and high fronto-parietal theta and alpha coherence appear to provide strong early evidence for recovery from UWS with high predictive sensitivity and specificity. Short and long-range coherence can have a diagnostic value in the prognosis of recovery from UWS. PMID:26984609

  9. EEG Changes Due to Experimentally Induced 3G Mobile Phone Radiation

    PubMed Central

    Roggeveen, Suzanne; van Os, Jim; Viechtbauer, Wolfgang; Lousberg, Richel

    2015-01-01

    The aim of this study was to investigate whether a 15-minute placement of a 3G dialing mobile phone causes direct changes in EEG activity compared to the placement of a sham phone. Furthermore, it was investigated whether placement of the mobile phone on the ear or the heart would result in different outcomes. Thirty-one healthy females participated. All subjects were measured twice: on one of the two days the mobile phone was attached to the ear, the other day to the chest. In this single-blind, cross-over design, assessments in the sham phone condition were conducted directly preceding and following the mobile phone exposure. During each assessment, EEG activity and radiofrequency radiation were recorded jointly. Delta, theta, alpha, slowbeta, fastbeta, and gamma activity was computed. The association between radiation exposure and the EEG was tested using multilevel random regression analyses with radiation as predictor of main interest. Significant radiation effects were found for the alpha, slowbeta, fastbeta, and gamma bands. When analyzed separately, ear location of the phone was associated with significant results, while chest placement was not. The results support the notion that EEG alterations are associated with mobile phone usage and that the effect is dependent on site of placement. Further studies are required to demonstrate the physiological relevance of these findings. PMID:26053854

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

    ERIC Educational Resources Information Center

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

    2011-01-01

    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.…

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

    ERIC Educational Resources Information Center

    Jausovec, Norbert

    2000-01-01

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

  12. Golf putt outcomes are predicted by sensorimotor cerebral EEG rhythms

    PubMed Central

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

    2008-01-01

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

  13. Golf putt outcomes are predicted by sensorimotor cerebral EEG rhythms.

    PubMed

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

    2008-01-01

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

  14. Analysis of EEG Related Saccadic Eye Movement

    NASA Astrophysics Data System (ADS)

    Funase, Arao; Kuno, Yoshiaki; Okuma, Shigeru; Yagi, Tohru

    Our final goal is to establish the model for saccadic eye movement that connects the saccade and the electroencephalogram(EEG). As the first step toward this goal, we recorded and analyzed the saccade-related EEG. In the study recorded in this paper, we tried detecting a certain EEG that is peculiar to the eye movement. In these experiments, each subject was instructed to point their eyes toward visual targets (LEDs) or the direction of the sound sources (buzzers). In the control cases, the EEG was recorded in the case of no eye movemens. As results, in the visual experiments, we found that the potential of EEG changed sharply on the occipital lobe just before eye movement. Furthermore, in the case of the auditory experiments, similar results were observed. In the case of the visual experiments and auditory experiments without eye movement, we could not observed the EEG changed sharply. Moreover, when the subject moved his/her eyes toward a right-side target, a change in EEG potential was found on the right occipital lobe. On the contrary, when the subject moved his/her eyes toward a left-side target, a sharp change in EEG potential was found on the left occipital lobe.

  15. EEG entropy measures in anesthesia

    PubMed Central

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

    2015-01-01

    Highlights: ► Twelve entropy indices were systematically compared in monitoring depth of anesthesia and detecting burst suppression.► Renyi permutation entropy performed best in tracking EEG changes associated with different anesthesia states.► Approximate Entropy and Sample Entropy performed best in detecting burst suppression. Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs' effect is lacking. In this study, we compare the capability of 12 entropy indices for monitoring depth of anesthesia (DoA) and detecting the burst suppression pattern (BSP), in anesthesia induced by GABAergic agents. Methods: Twelve indices were investigated, namely Response Entropy (RE) and State entropy (SE), three wavelet entropy (WE) measures [Shannon WE (SWE), Tsallis WE (TWE), and Renyi WE (RWE)], Hilbert-Huang spectral entropy (HHSE), approximate entropy (ApEn), sample entropy (SampEn), Fuzzy entropy, and three permutation entropy (PE) measures [Shannon PE (SPE), Tsallis PE (TPE) and Renyi PE (RPE)]. Two EEG data sets from sevoflurane-induced and isoflurane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, pharmacokinetic/pharmacodynamic (PK/PD) modeling and prediction probability (Pk) analysis were applied. The multifractal detrended fluctuation analysis (MDFA) as a non-entropy measure was compared. Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline variability, higher coefficient of determination (R2) and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an advantage in computation efficiency compared with MDFA. Conclusion: Each entropy index has its advantages and disadvantages in estimating DoA. Overall, it is suggested that the RPE index was a superior measure. Investigating the advantages and disadvantages of these entropy indices could help improve current clinical indices for monitoring DoA. PMID:25741277

  16. Alpha thalassaemia in Yemeni children with sickle cell disease.

    PubMed

    el-Hazmi, M A; Warsy, A S

    1999-12-01

    Alpha thalassaemia frequently occurs in several of the Middle Eastern populations. This study was conducted on 26 sickle cell disease (SCD) patients from Yemen and 19 normal children (Hb AA) living in Riyadh, Saudi Arabia. Blood samples were extracted by venepuncture, and haematological and biochemical parameters were estimated. DNA was extracted from the buffy coat and analysed for alpha-gene arrangement using Bam HI and Bgl II. The frequency of alpha-gene deletion in the total Yemeni group (26 SCD + 19 Hb AA) was 0.311 for one alpha-gene deletion (-alpha/alpha alpha) and 0.13 for two alpha-gene deletions (-alpha/-alpha). When separated on the basis of the Hb phenotype the alpha-gene deletion frequency was significantly higher (-alpha/alpha alpha = 0.346 and -alpha/-alpha = 0.231) in the SCD patients compared to the normal Hb AA group (-alpha/alpha alpha = 0.263 and -alpha/-alpha = 0). In the Hb AA group one child had triple alpha-gene arrangement (alpha alpha alpha/alpha alpha) giving an overall frequency of triple alpha-gene as 0.022. Haematological parameters showed variations in the SCD patients with and without alpha-gene deletion. This paper shows for the first time that alpha-gene deletion occurs in the Yemenis and the frequency is higher in patients with SCD. Further population-based studies are required to determine the exact frequency of the different types of alpha-thalassaemias in the overall Yemeni population. PMID:10667010

  17. Functional Connectivity Changes in Resting-State EEG as Potential Biomarker for Amyotrophic Lateral Sclerosis

    PubMed Central

    Iyer, Parameswaran Mahadeva; Egan, Catriona; Pinto-Grau, Marta; Burke, Tom; Elamin, Marwa; Nasseroleslami, Bahman; Pender, Niall; Lalor, Edmund C.; Hardiman, Orla

    2015-01-01

    Background Amyotrophic Lateral Sclerosis (ALS) is heterogeneous and overlaps with frontotemporal dementia. Spectral EEG can predict damage in structural and functional networks in frontotemporal dementia but has never been applied to ALS. Methods 18 incident ALS patients with normal cognition and 17 age matched controls underwent 128 channel EEG and neuropsychology assessment. The EEG data was analyzed using FieldTrip software in MATLAB to calculate simple connectivity measures and scalp network measures. sLORETA was used in nodal analysis for source localization and same methods were applied as above to calculate nodal network measures. Graph theory measures were used to assess network integrity. Results Cross spectral density in alpha band was higher in patients. In ALS patients, increased degree values of the network nodes was noted in the central and frontal regions in the theta band across seven of the different connectivity maps (p<0.0005). Among patients, clustering coefficient in alpha and gamma bands was increased in all regions of the scalp and connectivity were significantly increased (p=0.02). Nodal network showed increased assortativity in alpha band in the patients group. The Clustering Coefficient in Partial Directed Connectivity (PDC) showed significantly higher values for patients in alpha, beta, gamma, theta and delta frequencies (p=0.05). Discussion There is increased connectivity in the fronto-central regions of the scalp and areas corresponding to Salience and Default Mode network in ALS, suggesting a pathologic disruption of neuronal networking in early disease states. Spectral EEG has potential utility as a biomarker in ALS. PMID:26091258

  18. EEG Spectral Features Discriminate between Alzheimer’s and Vascular Dementia

    PubMed Central

    Neto, Emanuel; Allen, Elena A.; Aurlien, Harald; Nordby, Helge; Eichele, Tom

    2015-01-01

    Alzheimer’s disease (AD) and vascular dementia (VaD) present with similar clinical symptoms of cognitive decline, but the underlying pathophysiological mechanisms differ. To determine whether clinical electroencephalography (EEG) can provide information relevant to discriminate between these diagnoses, we used quantitative EEG analysis to compare the spectra between non-medicated patients with AD (n = 77) and VaD (n = 77) and healthy elderly normal controls (NC) (n = 77). We use curve-fitting with a combination of a power loss and Gaussian function to model the averaged resting-state spectra of each EEG channel extracting six parameters. We assessed the performance of our model and tested the extracted parameters for group differentiation. We performed regression analysis in a multivariate analysis of covariance with group, age, gender, and number of epochs as predictors and further explored the topographical group differences with pair-wise contrasts. Significant topographical differences between the groups were found in several of the extracted features. Both AD and VaD groups showed increased delta power when compared to NC, whereas the AD patients showed a decrease in alpha power for occipital and temporal regions when compared with NC. The VaD patients had higher alpha power than NC and AD. The AD and VaD groups showed slowing of the alpha rhythm. Variability of the alpha frequency was wider for both AD and VaD groups. There was a general decrease in beta power for both AD and VaD. The proposed model is useful to parameterize spectra, which allowed extracting relevant clinical EEG key features that move toward simple and interpretable diagnostic criteria. PMID:25762978

  19. Radiofrequency signal affects alpha band in resting electroencephalogram.

    PubMed

    Ghosn, Rania; Yahia-Cherif, Lydia; Hugueville, Laurent; Ducorps, Antoine; Lemaréchal, Jean-Didier; Thuróczy, György; de Seze, René; Selmaoui, Brahim

    2015-04-01

    The aim of the present work was to investigate the effects of the radiofrequency (RF) electromagnetic fields (EMFs) on human resting EEG with a control of some parameters that are known to affect alpha band, such as electrode impedance, salivary cortisol, and caffeine. Eyes-open and eyes-closed resting EEG data were recorded in 26 healthy young subjects under two conditions: sham exposure and real exposure in double-blind, counterbalanced, crossover design. Spectral power of EEG rhythms was calculated for the alpha band (8-12 Hz). Saliva samples were collected before and after the study. Salivary cortisol and caffeine were assessed by ELISA and HPLC, respectively. The electrode impedance was recorded at the beginning of each run. Compared with the sham session, the exposure session showed a statistically significant (P < 0.0001) decrease of the alpha band spectral power during closed-eyes condition. This effect persisted in the postexposure session (P < 0.0001). No significant changes were detected in electrode impedance, salivary cortisol, and caffeine in the sham session compared with the exposure one. These results suggest that GSM-EMFs of a mobile phone affect the alpha band within spectral power of resting human EEG. PMID:25695646

  20. Radiofrequency signal affects alpha band in resting electroencephalogram

    PubMed Central

    Ghosn, Rania; Yahia-Cherif, Lydia; Hugueville, Laurent; Ducorps, Antoine; Lemaréchal, Jean-Didier; Thuróczy, György; de Seze, René

    2015-01-01

    The aim of the present work was to investigate the effects of the radiofrequency (RF) electromagnetic fields (EMFs) on human resting EEG with a control of some parameters that are known to affect alpha band, such as electrode impedance, salivary cortisol, and caffeine. Eyes-open and eyes-closed resting EEG data were recorded in 26 healthy young subjects under two conditions: sham exposure and real exposure in double-blind, counterbalanced, crossover design. Spectral power of EEG rhythms was calculated for the alpha band (8–12 Hz). Saliva samples were collected before and after the study. Salivary cortisol and caffeine were assessed by ELISA and HPLC, respectively. The electrode impedance was recorded at the beginning of each run. Compared with the sham session, the exposure session showed a statistically significant (P < 0.0001) decrease of the alpha band spectral power during closed-eyes condition. This effect persisted in the postexposure session (P < 0.0001). No significant changes were detected in electrode impedance, salivary cortisol, and caffeine in the sham session compared with the exposure one. These results suggest that GSM-EMFs of a mobile phone affect the alpha band within spectral power of resting human EEG. PMID:25695646

  1. Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders

    ERIC Educational Resources Information Center

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

    2015-01-01

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

  2. Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders

    ERIC Educational Resources Information Center

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

    2015-01-01

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

  3. Functional Connectivity and Quantitative EEG in Women with Alcohol Use Disorders: A Resting-State Study.

    PubMed

    Herrera-Díaz, Adianes; Mendoza-Quiñones, Raúl; Melie-Garcia, Lester; Martínez-Montes, Eduardo; Sanabria-Diaz, Gretel; Romero-Quintana, Yuniel; Salazar-Guerra, Iraklys; Carballoso-Acosta, Mario; Caballero-Moreno, Antonio

    2016-05-01

    This study was aimed at exploring the electroencephalographic features associated with alcohol use disorders (AUD) during a resting-state condition, by using quantitative EEG and Functional Connectivity analyses. In addition, we explored whether EEG functional connectivity is associated with trait impulsivity. Absolute and relative powers and Synchronization Likelihood (SL) as a measure of functional connectivity were analyzed in 15 AUD women and fifteen controls matched in age, gender and education. Correlation analysis between self-report impulsivity as measured by the Barratt impulsiveness Scale (BIS-11) and SL values of AUD patients were performed. Our results showed increased absolute and relative beta power in AUD patients compared to matched controls, and reduced functional connectivity in AUD patients predominantly in the beta and alpha bands. Impaired connectivity was distributed at fronto-central and occipito-parietal regions in the alpha band, and over the entire scalp in the beta band. We also found that impaired functional connectivity particularly in alpha band at fronto-central areas was negative correlated with non-planning dimension of impulsivity. These findings suggest that functional brain abnormalities are present in AUD patients and a disruption of resting-state EEG functional connectivity is associated with psychopathological traits of addictive behavior. PMID:26660886

  4. Serum anticholinergic activity and cerebral cholinergic dysfunction: An EEG study in frail elderly with and without delirium

    PubMed Central

    Thomas, Christine; Hestermann, Ute; Kopitz, Juergen; Plaschke, Konstanze; Oster, Peter; Driessen, Martin; Mundt, Christoph; Weisbrod, Matthias

    2008-01-01

    Background Delirium increases morbidity, mortality and healthcare costs especially in the elderly. Serum anticholinergic activity (SAA) is a suggested biomarker for anticholinergic burden and delirium risk, but the association with cerebral cholinergic function remains unclear. To clarify this relationship, we prospectively assessed the correlation of SAA with quantitative electroencephalography (qEEG) power, delirium occurrence, functional and cognitive measures in a cross-sectional sample of acutely hospitalized elderly (> 80 y) with high dementia and delirium prevalence. Methods 61 consecutively admitted patients over 80 years underwent an extensive clinical and neuropsychological evaluation. SAA was determined by using radio receptor assay as developed by Tune, and standard as well as quantitative EEGs were obtained. Results 15 patients had dementia with additional delirium (DD) according to expert consensus using DSM-IV criteria, 31 suffered from dementia without delirium (D), 15 were cognitively unimpaired (CU). SAA was clearly detectable in all patients but one (mean 10.9 ± 7.1 pmol/ml), but was not associated with expert-panel approved delirium diagnosis or cognitive functions. Delirium-associated EEG abnormalities included occipital slowing, peak power and alpha decrease, delta and theta power increase and slow wave ratio increase during active delirious states. EEG measures correlated significantly with cognitive performance and delirium severity, but not with SAA levels. Conclusion In elderly with acute disease, EEG parameters reliable indicate delirium, but SAA does not seem to reflect cerebral cholinergic function as measured by EEG and is not related to delirium diagnosis. PMID:18793418

  5. Enhanced connectivity between visual cortex and other regions of the brain in autism: a REM sleep EEG coherence study.

    PubMed

    Léveillé, Cathy; Barbeau, Elise B; Bolduc, Christianne; Limoges, Elyse; Berthiaume, Claude; Chevrier, Elyse; Mottron, Laurent; Godbout, Roger

    2010-10-01

    Functional interregional neural coupling was measured as EEG coherence during REM sleep, a state of endogenous cortical activation, in 9 adult autistic individuals (21.1±4.0 years) and 13 typically developed controls (21.5±4.3 years) monitored for two consecutive nights in a sleep laboratory. Spectral analysis was performed on 60 s of artefact-free EEG samples distributed equally throughout the first four REM sleep periods of the second night. EEG coherence was calculated for six frequency bands (delta, theta, alpha, sigma, beta, and total spectrum) using a 22-electrode montage. The magnitude of coherence function was computed for intra- and interhemispheric pairs of recording sites. Results were compared by Multivariate Analysis of Variance (MANOVA). Each time the autistic group showed a greater EEG coherence than the controls; it involved intrahemispheric communication among the left visual cortex (O1) and other regions either close to or distant from the occipital cortex. In contrast, lower coherence values involved frontal electrodes in the right hemisphere. No significant differences between groups were found for interhemispheric EEG coherence. These results show that the analysis of EEG coherence during REM sleep can disclose patterns of cortical connectivity that can be reduced or increased in adults with autism compared to typically developed individuals, depending of the cortical areas studied. Superior coherence involving visual perceptual areas in autism is consistent with an enhanced role of perception in autistic brain organization. PMID:20717953

  6. Carbon-wire loop based artifact correction outperforms post-processing EEG/fMRI corrections--A validation of a real-time simultaneous EEG/fMRI correction method.

    PubMed

    van der Meer, Johan N; Pampel, André; Van Someren, Eus J W; Ramautar, Jennifer R; van der Werf, Ysbrand D; Gomez-Herrero, German; Lepsien, Jöran; Hellrung, Lydia; Hinrichs, Hermann; Möller, Harald E; Walter, Martin

    2016-01-15

    Simultaneous EEG-fMRI combines two powerful neuroimaging techniques, but the EEG signal suffers from severe artifacts in the MRI environment that are difficult to remove. These are the MR scanning artifact and the blood-pulsation artifact--strategies to remove them are a topic of ongoing research. Additionally large, unsystematic artifacts are produced across the full frequency spectrum by the magnet's helium pump (and ventilator) systems which are notoriously hard to remove. As a consequence, experimenters routinely deactivate the helium pump during simultaneous EEG-fMRI acquisitions which potentially risks damaging the MRI system and necessitates more frequent and expensive helium refills. We present a novel correction method addressing both helium pump and ballisto-cardiac (BCG) artifacts, consisting of carbon-wire loops (CWL) as additional sensors to accurately track unpredictable artifacts related to subtle movements in the scanner, and an EEGLAB plugin to perform artifact correction. We compare signal-to-noise metrics of EEG data, corrected with CWL and three conventional correction methods, for helium pump off and on measurements. Because the CWL setup records signals in real-time, it fits requirements of applications where immediate correction is necessary, such as neuro-feedback applications or stimulation time-locked to specific sleep oscillations. The comparison metrics in this paper relate to: (1) the EEG signal itself, (2) the "eyes open vs. eyes closed" effect, and (3) an assessment of how the artifact corrections impacts the ability to perform meaningful correlations between EEG alpha power and the BOLD signal. Results show that the CWL correction corrects for He pump artifact and also produces EEG data more comparable to EEG obtained outside the magnet than conventional post-processing methods. PMID:26505301

  7. Neural network model of cortical EEG response to olfactory stimuli

    NASA Astrophysics Data System (ADS)

    Dunbar, George L.; Van Toller, Steve

    1995-04-01

    We describe three experiments attempting to model differences in cortical EEG following stimulation with different odors. The data used in these experiments was obtained in previous studies, described briefly here. Subjects sit in an environmentally stabilized low odor cubicle. Twenty-eight electrodes are placed on the scalp and connect the subject to a neurosciences brain imager, which digitizes cortical EEG response. In a given trial, a specific odor is introduced, and the response recorded. In the first experiment, alpha wave data from a subset of ten electrodes and a single subject was used. In the original experiment, the subject was presented with a number of odors and the resulting brain electrical activity was resolved into 16 time slices (5 preceding presentation, 4 during presentation and 7 following presentation). Only data from frames 6, 7 and 8 (during presentation) was used here. A model was constructed to discriminate morning from afternoon responses. The network used measurements from 10 electrodes as input, and backpropagation was used for training. During training, the network was presented with responses to just one odor. Generalization was demonstrated for five other odors. The weights in the network have been analyzed and indicate a role for a specific group of electrode sites in this discrimination. The second experiment involved constructing a network to discriminate cortical EEG responses to two odors. In the original experiment from which we drew our data, fourteen subjects were presented with each odor once. Data from only the frame at first presentation of the odor were used here. Data from three subjects (chosen pseudo-randomly) was selected for use in the generalization phase and dropped from the training set. Output targets were constructed that took account of subjective ratings of `pleasantness.' A feed-forward network with twenty-eight input units was trained using data from the eleven remaining subjects, using conjugate gradient descent.

  8. Early EEG Improvement after Ketogenic Diet Initiation

    PubMed Central

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

    2011-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Dijk, D. J.

    1999-01-01

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

  10. Topographic distribution of homing receptors on B and T cells in human gut-associated lymphoid tissue: relation of L-selectin and integrin alpha 4 beta 7 to naive and memory phenotypes.

    PubMed Central

    Farstad, I. N.; Halstensen, T. S.; Kvale, D.; Fausa, O.; Brandtzaeg, P.

    1997-01-01

    In mice, integrin alpha 4 beta 7 is the main receptor used by lymphocytes that home to the Peyer's patches, although L-selectin contributes to the initial interaction with high endothelial venules. Less is known about the expression and function of these adhesion molecules in humans. The distribution of L-selectin and alpha 4 beta 7 on various B- and T-cell subsets was examined in human Peyer's patches (n = 8) and appendix (n = 4), collectively called gut-associated lymphoid tissue. Multicolor immunophenotyping was performed on cryosections, and dispersed cells were examined by flow cytometry. In cryosections, CD45RA+ T cells around and within interfollicular high endothelial venules, as well as surface (s)IgD+ B lymphocytes in the follicle mantles, often expressed abundant L-selectin but only intermediate levels of alpha 4 beta 7. CD45RO+ T cells and sIgD- B cells expressed higher levels of alpha 4 beta 7 and were often located near putative efferent lymphatics; only a small fraction (< 20%) of such memory cells expressed L-selectin. By flow cytometry, considerably more T than B lymphocytes co-expressed L-selectin and alpha 4 beta 7 (40% versus 25% and 67% versus 39%, respectively). In samples with many L-selectin+ cells (> 30%), more of these lymphocytes co-expressed alpha 4 beta 7 than in samples with few L-selectin+ cells. Because L-selectin and alpha 4 beta 7 were co-expressed on lymphocytes located near high endothelial venules, and because such co-expression was relatively common when many L-selectin+ cells were present, both of these molecules might participate in homing to human gut-associated lymphoid tissue. Such homing is probably most pronounced for T lymphocytes that were found to express L-selectin and alpha 4 beta 7 more often than B lymphocytes. The selective and relatively high expression of alpha 4 beta 7 on memory cells located near efferent lymphatics indicated a different migratory capacity; after exit from gut-associated lymphoid tissue, such stimulated cells might home mainly to mucosal effector sites. Images Figure 1 Figure 2 PMID:9006335

  11. Discriminant analysis and equivalent source localization of the EEG related to cognitive functions.

    PubMed

    Lind, J C; Flor-Henry, P; Koles, Z J

    1999-01-01

    Discriminant analysis and EEG source localization methods were employed to compare groups of normal subjects during different cognitive conditions using 43-channel EEG recordings in the alpha (8-13 Hz) frequency band. Recordings were obtained from 69 dextral females during 2 passive conditions, Eyes-Open and Eyes-Closed, and 2 active conditions, Word-Finding and Dot-Localization. The cross-spectral matrix between all of the electrode sites was used to characterize the EEGs obtained during each condition. The subjects were partitioned into training and test sets and quadratic discriminant functions were constructed from the training sets to classify the EEGs. The discriminant functions successfully classified both the training and test sets at rates approaching 80%. The classification was repeated using only the diagonal (power spectral) elements of the cross-spectral matrices in the discriminant functions and this approach was successful in discriminating between the EEGs from the passive cognitive conditions but failed to discriminate between the EEGs from the active conditions. Source localization using a modified MUSIC algorithm indicated that the centers of brain electrical activity that distinguished the Eyes-Closed condition from the Eyes-Open condition were located in the medial occipital and right frontal regions. Centers of electrical activity that distinguished the Word-Finding condition from the Dot-Localization condition were located in the right medial posterior and left temporal regions. Validation of the locations of the centers of activity was accomplished by repeating the classification procedures using the spatial patterns generated on the scalp by dipole current sources placed at these locations. PMID:10449258

  12. The Sleep EEG as a Marker of Intellectual Ability in School Age Children

    PubMed Central

    Geiger, Anja; Huber, Reto; Kurth, Salomé; Ringli, Maya; Jenni, Oskar G.; Achermann, Peter

    2011-01-01

    Study Objectives: To investigate the within-subject stability in the sleep EEG and the association between the sleep EEG and intellectual abilities in 9- to 12-year-old children. Design: Intellectual ability (WISC-IV, full scale, fluid, and verbal IQ, working memory, speed of processing) were examined and all-night polysomnography was performed (2 nights per subject). Setting: Sleep laboratory. Participants: Fourteen healthy children (mean age 10.5 ± 1.0 years; 6 girls). Measurements and Results: Spectral analysis was performed on artifact-free NREM sleep epochs (C3/A2). To determine intra-individual stability and inter-individual variability of the sleep EEG, power spectra were used as feature vectors for the estimation of Euclidean distances, and intraclass correlation coefficients (ICC) were calculated for the 2 nights. Sleep spindle peaks were identified for each individual and individual sigma band power was determined. Trait-like aspects of the sleep EEG were observed for sleep stage variables and spectral power. Within-subject distances were smaller than between-subject distances and ICC values ranged from 0.72 to 0.96. Correlations between spectral power in individual frequency bins and intelligence scores revealed clusters of positive associations in the alpha, sigma, and beta range for full scale IQ, fluid IQ, and working memory. Similar to adults, sigma power correlated with full scale (r = 0.67) and fluid IQ (r = 0.65), but not with verbal IQ. Spindle peak frequency was negatively related to full scale IQ (r = −0.56). Conclusions: The sleep EEG during childhood shows high within-subject stability and may be a marker for intellectual ability. Citation: Geiger A; Huber R; Kurth S; Ringli M; Jenni OG; Achermann P. The sleep EEG as a marker of intellectual ability in school age children. SLEEP 2011;34(2):181-189. PMID:21286251

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

    PubMed

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

    2014-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  15. The phase of ongoing EEG oscillations predicts visual perception.

    PubMed

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

    2009-06-17

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

  16. Heritability of resting state EEG functional connectivity patterns.

    PubMed

    Schutte, Nienke M; Hansell, Narelle K; de Geus, Eco J C; Martin, Nicholas G; Wright, Margaret J; Smit, Dirk J A

    2013-10-01

    We examined the genetic architecture of functional brain connectivity measures in resting state electroencephalographic (EEG) recordings. Previous studies in Dutch twins have suggested that genetic factors are a main source of variance in functional brain connectivity derived from EEG recordings. In addition, qualitative descriptors of the brain network derived from graph analysis - network clustering and average path length - are also heritable traits. Here we replicated previous findings for connectivity, quantified by the synchronization likelihood, and the graph theoretical parameters cluster coefficient and path length in an Australian sample of 16-year-old twins (879) and their siblings (93). Modeling of monozygotic and dizygotic twins and sibling resemblance indicated heritability estimates of the synchronization likelihood (27-74%) and cluster coefficient and path length in the alpha and theta band (40-44% and 23-40% respectively) and path length in the beta band frequency (41%). This corroborates synchronization likelihood and its graph theoretical derivatives cluster coefficient and path length as potential endophenotypes for behavioral traits and neurological disorders. PMID:23931641

  17. Quantified EEG in different G situations

    NASA Astrophysics Data System (ADS)

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

    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.

  18. [Continuous EEG monitoring for aneurysmal subarachnoid hemorrhage].

    PubMed

    Pugin, D; Vulliemoz, S; Bijlenga, P; Gasche, Y

    2014-12-10

    Subarachnoid hemorrhage (SAH) still carries a high morbidity and mortality, despite improvement in surgical and medical management. Seizures and delayed cerebral ischemia (DCI) secondary to vasospasm or cortical spreading depression are frequent after SAH. Continuous EEG allows early detection of non-convulsive seizures or delayed cerebral ischemia and may become a promissing tool in the monitoring of SAH patients. However, its use in clinical practice is still limited because many resources are required for recording and analyzing continuous EEG. Moreover, we require more data to confirm the relationship between aggressive treatment of non-convulsive seizure or delayed cerebral ischemia triggered by continuous EEG and outcome. PMID:25632630

  19. Towards wireless emotional valence detection from EEG.

    PubMed

    Brown, Lindsay; Grundlehner, Bernard; Penders, Julien

    2011-01-01

    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

  20. Enabling computer decisions based on EEG input

    NASA Technical Reports Server (NTRS)

    Culpepper, Benjamin J.; Keller, Robert M.

    2003-01-01

    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.

  1. The Diagnostic Accuracy of Prolonged Ambulatory Versus Routine EEG.

    PubMed

    Keezer, Mark R; Simard-Tremblay, Elisabeth; Veilleux, Martin

    2016-04-01

    Prolonged ambulatory electroencephalography (paEEG) is increasingly used in clinical practice but its diagnostic accuracy relative to that of routine EEG (rEEG) remains uncertain. We examined a consecutive sample of 72 individuals who had undergone 32-channel paEEG immediately after an rEEG, creating perfectly matched EEG samples. Each recording was prospectively assessed for epileptiform discharges (ED) and nonepileptiform abnormalities. The median paEEG duration was 22.5 hours (interquartile range: 22.0-23.0). The sensitivity of paEEG was 2.23 times greater than that of rEEG [sensitivity ratio: 2.23 (95% CI = 1.49-3.34)] if a positive test was limited to the presence of epileptiform discharges. This benefit of paEEG versus rEEG was no longer evident if the definition of a positive test included nonepileptiform abnormalities (sensitivity ratio 1.26; 95% CI = 1.02-1.55). The specificity of the 2 tests was not evidently different (specificity ratio 0.67; 95% CI = 0.17-2.67). Twenty-six percent of paEEG recorded epileptic seizures while none of the rEEG did (absolute difference 26.0% (95% CI = 11.8-40.2). Our findings quantify the benefit of 32-channel paEEG, relative to rEEG, and support its role in the diagnosis and characterization of epilepsy. PMID:26376916

  2. Brain Networks Responsible for Sense of Agency: An EEG Study

    PubMed Central

    Shim, Miseon; Nahab, Fatta B.; Park, Jihye; Kim, Do-Won; Kakareka, John; Miletta, Nathanial; Hallett, Mark

    2015-01-01

    Background Self-agency (SA) is a person’s feeling that his action was generated by himself. The neural substrates of SA have been investigated in many neuroimaging studies, but the functional connectivity of identified regions has rarely been investigated. The goal of this study is to investigate the neural network related to SA. Methods SA of hand movements was modulated with virtual reality. We examined the cortical network relating to SA modulation with electroencephalography (EEG) power spectrum and phase coherence of alpha, beta, and gamma frequency bands in 16 right-handed, healthy volunteers. Results In the alpha band, significant relative power changes and phase coherence of alpha band were associated with SA modulation. The relative power decrease over the central, bilateral parietal, and right temporal regions (C4, Pz, P3, P4, T6) became larger as participants more effectively controlled the virtual hand movements. The phase coherence of the alpha band within frontal areas (F7-FP2, F7-Fz) was directly related to changes in SA. The functional connectivity was lower as the participants felt that they could control their virtual hand. In the other frequency bands, significant phase coherences were observed in the frontal (or central) to parietal, temporal, and occipital regions during SA modulation (Fz-O1, F3-O1, Cz-O1, C3-T4L in beta band; FP1-T6, FP1-O2, F7-T4L, F8-Cz in gamma band). Conclusions Our study suggests that alpha band activity may be the main neural oscillation of SA, which suggests that the neural network within the anterior frontal area may be important in the generation of SA. PMID:26270552

  3. Automatic seizure detection: going from sEEG to iEEG.

    PubMed

    Henriksen, Jonas; Remvig, Line S; Madsen, Rasmus E; Conradsen, Isa; Kjaer, Troels W; Thomsen, Carsten E; Sorensen, Helge B D

    2010-01-01

    Several different algorithms have been proposed for automatic detection of epileptic seizure based on both scalp and intracranial electroencephalography (sEEG and iEEG). Which modality that renders the best result is hard to assess though. From 16 patients with focal epilepsy, at least 24 hours of ictal and non-ictal iEEG were obtained. Characteristics of the seizures are represented by use of wavelet transformation (WT) features and classified by a support vector machine. When implementing a method used for sEEG on iEEG data, a great improvement in performance was obtained when the high frequency containing lower levels in the WT were included in the analysis. We were able to obtain a sensitivity of 96.4% and a false detection rate (FDR) of 0.20/h. In general, when implementing an automatic seizure detection algorithm made for sEEG on iEEG, great improvement can be obtained if a frequency band widening of the feature extraction is performed. This means that algorithms for sEEG should not be discarded for use on iEEG - they should be properly adjusted as exemplified in this paper. PMID:21095958

  4. Improving N1 classification by grouping EEG trials with phases of pre-stimulus EEG oscillations.

    PubMed

    Han, Li; Liang, Zhang; Jiacai, Zhang; Changming, Wang; Li, Yao; Xia, Wu; Xiaojuan, Guo

    2015-04-01

    A reactive brain-computer interface using electroencephalography (EEG) relies on the classification of evoked ERP responses. As the trial-to-trial variation is evitable in EEG signals, it is a challenge to capture the consistent classification features distribution. Clustering EEG trials with similar features and utilizing a specific classifier adjusted to each cluster can improve EEG classification. In this paper, instead of measuring the similarity of ERP features, the brain states during image stimuli presentation that evoked N1 responses were used to group EEG trials. The correlation between momentary phases of pre-stimulus EEG oscillations and N1 amplitudes was analyzed. The results demonstrated that the phases of time-frequency points about 5.3 Hz and 0.3 s before the stimulus onset have significant effect on the ERP classification accuracy. Our findings revealed that N1 components in ERP fluctuated with momentary phases of EEG. We also further studied the influence of pre-stimulus momentary phases on classification of N1 features. Results showed that linear classifiers demonstrated outstanding classification performance when training and testing trials have close momentary phases. Therefore, this gave us a new direction to improve EEG classification by grouping EEG trials with similar pre-stimulus phases and using each to train unit classifiers respectively. PMID:25852778

  5. The dark side of the alpha rhythm: fMRI evidence for induced alpha modulation during complete darkness.

    PubMed

    Ben-Simon, Eti; Podlipsky, Ilana; Okon-Singer, Hadas; Gruberger, Michal; Cvetkovic, Dean; Intrator, Nathan; Hendler, Talma

    2013-03-01

    The unique role of the EEG alpha rhythm in different states of cortical activity is still debated. The main theories regarding alpha function posit either sensory processing or attention allocation as the main processes governing its modulation. Closing and opening eyes, a well-known manipulation of the alpha rhythm, could be regarded as attention allocation from inward to outward focus though during light is also accompanied by visual change. To disentangle the effects of attention allocation and sensory visual input on alpha modulation, 14 healthy subjects were asked to open and close their eyes during conditions of light and of complete darkness while simultaneous recordings of EEG and fMRI were acquired. Thus, during complete darkness the eyes-open condition is not related to visual input but only to attention allocation, allowing direct examination of its role in alpha modulation. A data-driven ridge regression classifier was applied to the EEG data in order to ascertain the contribution of the alpha rhythm to eyes-open/eyes-closed inference in both lighting conditions. Classifier results revealed significant alpha contribution during both light and dark conditions, suggesting that alpha rhythm modulation is closely linked to the change in the direction of attention regardless of the presence of visual sensory input. Furthermore, fMRI activation maps derived from an alpha modulation time-course during the complete darkness condition exhibited a right frontal cortical network associated with attention allocation. These findings support the importance of top-down processes such as attention allocation to alpha rhythm modulation, possibly as a prerequisite to its known bottom-up processing of sensory input. PMID:23216771

  6. Energetical bases of extraversion: effort, arousal, EEG, and performance.

    PubMed

    Beauducel, André; Brocke, Burkhard; Leue, Anja

    2006-11-01

    This study investigates an extension of H.J. Eysenck's [Eysenck, H.J., 1967. The Biological Basis of Personality. Charles C. Thomas, Springfield, IL] arousal theory of extraversion, incorporating an effort system as a control system for different aspects of arousal. Extraverts were expected to have lower levels of reticocortical arousal than introverts, to invest more effort, and to have lower task performance in a monotonous vigilance task. In a 40-min vigilance task, participants had to react to the shorter of two 1 kHz tones presented binaurally at an event rate of 200 per 10 min. Spontaneous EEG, event-related potential, and performance data of 40 extremely introverted and 41 extremely extraverted students were available for statistical analysis. A tendency for lower arousal levels of extraverts (alpha 2 band), the expected higher effort investment (P300) and a lower performance (hits) of extraverts were found. PMID:16426692

  7. Detection of nocturnal hypoglycemic episodes using EEG signals.

    PubMed

    Nguyen, Hung T; Jones, Timothy W

    2010-01-01

    Hypoglycemia (low blood glucose) or the fear of hypoglycemia constitutes a significant barrier to the achievement of good glycemic control in the insulin treated diabetic patients. By measuring physiological responses derived from EEG and analyzing these, we establish that hypoglycemia can be detected non-invasively. From a clinical study of six children with type 1 diabetes (T1D), associated with hypoglycemic episodes at night, their centroid (centre of gravity) alpha frequency reduced significantly (P〈0.001) and their centroid theta frequency increased significantly (P〈0.02). The overall data were organized into a training set (3 patients) and a test set (another 3 patients) randomly selected. Using the optimal Bayesian neural network which was derived from the training set with the highest log evidence, the estimated blood glucose profiles produced a significant correlation (P〈0.005) against measured values in the test set. PMID:21096665

  8. Differential Oscillatory EEG between Attention Deficit Hyperactivity Disorder Subtypes and Typically Developing Adolescents

    PubMed Central

    Mazaheri, Ali; Fassbender, Catherine; Coffey-Corina, Sharon; Hartanto, Tadeus A.; Schweitzer, Julie B.; Mangun, George R.

    2013-01-01

    Background A neurobiological-based classification of Attention Deficit Hyperactivity Disorder (ADHD) subtypes has thus far remained elusive. The aim of this study was to use oscillatory changes in the electroencephalogram (EEG) related to informative cue processing, motor preparation, and top-down control to investigate neurophysiological differences between typically developing (TD) adolescents, and those diagnosed with predominantly inattentive (IA), or combined (associated with symptoms of inattention, as well as impulsivity/hyperactivity; CB) subtypes of ADHD. Methods EEG was recorded from 57 rigorously screened adolescents (aged 12 to17 years; 23 TD, 17 IA and 17 CB), while they performed a cued flanker task. We examined the oscillatory changes in theta (3–5 Hz), alpha (8–12 Hz) and beta (22–25 Hz) EEG bands following cues that informed participants with which hand they would subsequently be required to respond. Results Relative to TD adolescents the IA group showed significantly less post-cue alpha suppression, suggesting diminished processing of the cue in the visual cortex, whereas the CB group showed significantly less beta suppression at the electrode contralateral to the cued response hand, suggesting poor motor planning. Finally, both ADHD subtypes showed weak functional connectivity between frontal theta and posterior alpha, suggesting common top-down control impairment. Conclusions We found both distinct and common task-related neurophysiological impairments in ADHD subtypes. Our results suggest that task-induced changes in EEG oscillations provide an objective measure, which in conjunction with other sources of information might help distinguish between ADHD subtypes and therefore aid in diagnoses and evaluation of treatment. PMID:24120092

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

    PubMed Central

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

    2010-01-01

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

  10. Ontogenetic patterns of frequency-power spectra elicited by flickering light in children: a comparative study of evoked and background EEGs.

    PubMed

    Vítová, Z; Srajer, J

    1975-01-01

    Frequency-power spectra of the EEG evoked by repeptitive photic stimulation and of the background EEG were studied during childhood in 43 awake subjects aged between 2 months and 14 years. EEG activity was recorded from the middle parieto-occipital region with the aid of a 1-channel analyzer Lysograf-Alvar, analysing 16 frequencies in the range from 2 to 28 c/sec. The responsiveness of the central nervous system to flickering light improved in the course of childhood in parallel with the significant decline of delta activity and with the prominent increase of alpha intensity in the resting EEG. The 4th month of life appeared to be a marked turning point in the development of evoked and background EEGs. From that age, the bioelectric power at the flash rate corresponding to photic "driving" began to increase together with the highest and optimal driving frequencies. The flash rate, at which evoked potentials changed into the "driven" rhythm, also shifted towards higher frequencies. Subsequently, the amount of energy in the resting EEG increased significantly within the theta, alpha and beta bands and, on the contrary, a prominent decline was observed in the delta range. Marked ontogenetic changes at this age closely coincided with the rapid development of exogenous fibres in the occipital cortex, including the thalamo-cortical conncetions, and fibres of the neuropil in cortical layer I, which might play an important role in the genesis of background and "driven" in the occipital region. PMID:128017

  11. EEG frequency analysis in conversion and somatoform disorder.

    PubMed

    Drake, M E; Padamadan, H; Pakalnis, A

    1988-07-01

    Patients with "hysterical" neurologic symptoms have long puzzled neurologists and psychiatrists. "Hysteria" has recently been subdivided into conversion and somatoform disorder. We applied computerized EEG frequency analysis to 10 patients with diagnosed conversion disorder, 10 somatoform disorder patients, and 10 control subjects. One minute EEG samples composed of 4 sec epochs were recorded from left frontal (F7-C3), right frontal (F8-C4), left posterior (T5-01) and right posterior (T6-02) derivations. Spectral power was calculated for 4 bands (0.25-4HZ, 4.25-8Hz, 8.25-13Hz, and 13.25-30Hz), and for the full frequency range. Low (0.25-8Hz) and high (8.25-30Hz) frequency bands were compared to determine high/low power ratios on the left and right (PHLL) and (PHLR), ratios of left/right front (PLRF) and posterior (PLRP) power, mean alpha frequency deviation frontally (FLRF) and posteriorly (FLRP), and mobility of left and right frontal power (MOLF and MORF). No significant differences were found between conversion disorder patients and controls in PHLL, PHLR, PLRP, and MORF. PLRF, FLRF and MOLF differed significantly between patients and controls. Power and frequency ratios of right frontal mobilities suggested a decrease in high frequency power, reduction in mean alpha frequency, and lower predominant frequency in the right frontal area in somatoform disorder patients as compared to controls, but significance was not reached. Somatoform and conversion disorder patients differed significantly in these spectral measures. These observations suggest that the two "hysterical" disorders may have distinct pathophysiology, and may be due to eventually identifiable cerebral dysfunction in some cases. PMID:3416496

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. Benefits, shortcomings, and costs of EEG monitoring.

    PubMed

    Green, R M; Messick, W J; Ricotta, J J; Charlton, M H; Satran, R; McBride, M M; DeWeese, J A

    1985-06-01

    A 5-year experience with 562 carotid endarterectomies, using electroencephalogram (EEG) monitoring and selective shunting, was reviewed. EEG changes occurred in 102 patients (18%). The frequency of EEG changes, as related to cerebral vascular symptoms, was as follows: transient ischemic attacks, seven per cent (19/259); completed strokes, 37% (36/98); vertebral basilar insufficiency, 24% (32/135); asymptomatic, 21% (15/71). Patients with contralateral carotid occlusion exhibited EEG changes in 37% (28/76) of operations. Fifteen patients suffered perioperative strokes (2.6%). Nine of the 15 were associated with a technical problem of either thrombosis of the internal carotid artery (five) or emboli (four). Technical problems were more common when shunts were used (five per cent) than when they were not (0.9%). Patients who suffered strokes prior to surgery were more at risk to develop a perioperative stroke (three per cent) than those not suffering prior strokes (0.3%). The EEG did not change in three patients who had lacunar infarcts prior to surgery and who awoke with a worsened deficit. Our series does not clearly establish the advantages of EEG monitoring, which is expensive (+375/patient) and may not detect ischemia in all areas of the brain. However, the use of shunts may introduce a risk of stroke due to technical error that is equal or greater than the risk of stroke due to hemodynamic ischemia. Since the need for protection is unpredictable by angiographic or clinical criteria, the benefit of EEG monitoring may be in reducing the incidence of shunting in those patients whose tracing remains normal after clamping. The decision to shunt, however, when there is electrical dysfunction after carotid clamping should be based not only on the EEG but also on the clinical signs and computed tomography (CT) scan. Our data does not show a net benefit in selective shunting unless the patient has sustained a stroke prior to surgery. PMID:3923954

  14. Ambulatory cassette EEG in epilepsy evaluation.

    PubMed

    Drake, M E; Pakalnis, A; Hietter, S A

    1989-10-01

    The economy and effectiveness of 24-hour ambulatory cassette EEG (AEEG) are increasingly recognized. We reviewed 735 AEEGs recorded between 1983 and 1989. These findings suggest that AEEG may confirm the ictal original of attacks in patients with known epilepsy, and may improve the yield of abnormality in epileptics with normal interictal EEG. Focal slowing may be seen less well on AEEG, and the yield of AEEG is low in random sampling of patients with infrequent or nonspecific symptoms. PMID:2586991

  15. Connectivity Measures in EEG Microstructural Sleep Elements.

    PubMed

    Sakellariou, Dimitris; Koupparis, Andreas M; Kokkinos, Vasileios; Koutroumanidis, Michalis; Kostopoulos, George K

    2016-01-01

    During Non-Rapid Eye Movement sleep (NREM) the brain is relatively disconnected from the environment, while connectedness between brain areas is also decreased. Evidence indicates, that these dynamic connectivity changes are delivered by microstructural elements of sleep: short periods of environmental stimuli evaluation followed by sleep promoting procedures. The connectivity patterns of the latter, among other aspects of sleep microstructure, are still to be fully elucidated. We suggest here a methodology for the assessment and investigation of the connectivity patterns of EEG microstructural elements, such as sleep spindles. The methodology combines techniques in the preprocessing, estimation, error assessing and visualization of results levels in order to allow the detailed examination of the connectivity aspects (levels and directionality of information flow) over frequency and time with notable resolution, while dealing with the volume conduction and EEG reference assessment. The high temporal and frequency resolution of the methodology will allow the association between the microelements and the dynamically forming networks that characterize them, and consequently possibly reveal aspects of the EEG microstructure. The proposed methodology is initially tested on artificially generated signals for proof of concept and subsequently applied to real EEG recordings via a custom built MATLAB-based tool developed for such studies. Preliminary results from 843 fast sleep spindles recorded in whole night sleep of 5 healthy volunteers indicate a prevailing pattern of interactions between centroparietal and frontal regions. We demonstrate hereby, an opening to our knowledge attempt to estimate the scalp EEG connectivity that characterizes fast sleep spindles via an "EEG-element connectivity" methodology we propose. The application of the latter, via a computational tool we developed suggests it is able to investigate the connectivity patterns related to the occurrence of EEG microstructural elements. Network characterization of specified physiological or pathological EEG microstructural elements can potentially be of great importance in the understanding, identification, and prediction of health and disease. PMID:26924980

  16. Connectivity Measures in EEG Microstructural Sleep Elements

    PubMed Central

    Sakellariou, Dimitris; Koupparis, Andreas M.; Kokkinos, Vasileios; Koutroumanidis, Michalis; Kostopoulos, George K.

    2016-01-01

    During Non-Rapid Eye Movement sleep (NREM) the brain is relatively disconnected from the environment, while connectedness between brain areas is also decreased. Evidence indicates, that these dynamic connectivity changes are delivered by microstructural elements of sleep: short periods of environmental stimuli evaluation followed by sleep promoting procedures. The connectivity patterns of the latter, among other aspects of sleep microstructure, are still to be fully elucidated. We suggest here a methodology for the assessment and investigation of the connectivity patterns of EEG microstructural elements, such as sleep spindles. The methodology combines techniques in the preprocessing, estimation, error assessing and visualization of results levels in order to allow the detailed examination of the connectivity aspects (levels and directionality of information flow) over frequency and time with notable resolution, while dealing with the volume conduction and EEG reference assessment. The high temporal and frequency resolution of the methodology will allow the association between the microelements and the dynamically forming networks that characterize them, and consequently possibly reveal aspects of the EEG microstructure. The proposed methodology is initially tested on artificially generated signals for proof of concept and subsequently applied to real EEG recordings via a custom built MATLAB-based tool developed for such studies. Preliminary results from 843 fast sleep spindles recorded in whole night sleep of 5 healthy volunteers indicate a prevailing pattern of interactions between centroparietal and frontal regions. We demonstrate hereby, an opening to our knowledge attempt to estimate the scalp EEG connectivity that characterizes fast sleep spindles via an “EEG-element connectivity” methodology we propose. The application of the latter, via a computational tool we developed suggests it is able to investigate the connectivity patterns related to the occurrence of EEG microstructural elements. Network characterization of specified physiological or pathological EEG microstructural elements can potentially be of great importance in the understanding, identification, and prediction of health and disease. PMID:26924980

  17. Human electroencephalographic (EEG) response to olfactory stimulation: two experiments using the aroma of food.

    PubMed

    Martin, G N

    1998-11-01

    The present studies sought to examine the effect of olfactory stimulation on human Central Nervous System activity. In the first experiment (n = 21), EEG response to the 'synthetic' odours of chocolate, spearmint, almond, strawberry, vegetable, garlic and onion, and cumin or no odour was recorded from 19 electrodes (F3, F4, F7, F8, Fz, T3, T4, T5, T6, P3, P4, Pz, O1, O2, C3, C4, Cz) in all EEG frequencies (delta, theta, alpha, beta1 and beta2). Exposure to the odour of chocolate was associated with significant reductions in theta activity when compared with the odours of almond and cumin, with a trend towards significance when compared with no-odour control. Exposure to the odour of spearmint was associated with a significant reduction in EEG theta when compared with the no-odour control. No significant effects were observed in other frequencies. In a second experiment (n = 15), EEG response to the odours of real foods (chocolate, baked beans, rotting pork) and two controls (no odour and hot water) was recorded as in Experiment 1. The odour of chocolate was associated with significantly less theta activity than was any other stimulus. It is hypothesised that the alterations in theta reflect shifts in attention or cognitive load during olfactory perception, with a reduction in theta indicating a reduced level of attention. PMID:9834885

  18. [Frequency analytic EEG study on the topic of temporal function disorders in transsexuality].

    PubMed

    Grasser, T; Keidel, M; Kockott, G

    1989-06-01

    A high rate of (temporal) EEG abnormalities within the group of transsexual patients has been previously described. These reports however were based on visual EEG analyses, which were not sufficiently statistically supported. It therefore seemed necessary to test this observations by utilizing quantitative frequency EEG analysis by using a larger group of transsexuals (n = 33). Fourier transformed data were recordings from T3-A1, T3-P3, T5-Cz, 01-Cz. The power of the delta-, theta-, alpha, and beta-bands were calculated as the percent of the total power (1,00-30,00 Hz). Different ratios of the absolute power values were computed. No significant differences of frequency-band related power, global power or power ratios between patients and normal subjects were found. There was also no separation on the basis of the genotypic sex of the subjects (Mann-Whitney-test). However 7 EEG's (21%) of the transsexual patients showed according to our interpretation temporo-parietal abnormalities. PMID:2503354

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

    PubMed Central

    Madhusudhan, B.K.

    2014-01-01

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

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

    PubMed

    Madhusudhan, B K

    2014-01-01

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

  1. Comparison of the EEG effects of midazolam, thiopental, and propofol: the role of underlying oscillatory systems.

    PubMed

    Feshchenko, V A; Veselis, R A; Reinsel, R A

    1997-01-01

    The EEG effects of 3 intravenous sedative drugs from different chemical families were studied during conscious sedation in 47 normal volunteers. The drugs studied were midazolam (a benzodiazepine), propofol (an alkylphenol) and thiopental (a barbiturate). Though these drugs cause different degrees of amnesia, they have the common EEG effects of suppressing alpha-rhythm and increasing total beta-power. A large portion of the increase in beta-power can be accounted for by beta-rhythms. We used the UNIFAC-EEG technique to differentiate oscillatory systems underlying the rhythms induced by these drugs in a quantitative fashion. While thiopental induced beta-rhythms which were similar to those appearing during drowsiness, midazolam and propofol induced beta-rhythms with substantially different characteristics. The differences between the beta-rhythms induced by drug infusion and previously described 'sleep spindles' are discussed. We conclude that a quantitative analysis of beta-rhythms can differentiate the effects of these drugs on the EEG. PMID:9246224

  2. Relationship between speed and EEG activity during imagined and executed hand movements.

    PubMed

    Yuan, Han; Perdoni, Christopher; He, Bin

    2010-04-01

    The relationship between primary motor cortex and movement kinematics has been shown in nonhuman primate studies of hand reaching or drawing tasks. Studies have demonstrated that the neural activities accompanying or immediately preceding the movement encode the direction, speed and other information. Here we investigated the relationship between the kinematics of imagined and actual hand movement, i.e. the clenching speed, and the EEG activity in ten human subjects. Study participants were asked to perform and imagine clenching of the left hand and right hand at various speeds. The EEG activity in the alpha (8-12 Hz) and beta (18-28 Hz) frequency bands were found to be linearly correlated with the speed of imagery clenching. Similar parametric modulation was also found during the execution of hand movements. A single equation relating the EEG activity to the speed and the hand (left versus right) was developed. This equation, which contained a linear independent combination of the two parameters, described the time-varying neural activity during the tasks. Based on the model, a regression approach was developed to decode the two parameters from the multiple-channel EEG signals. We demonstrated the continuous decoding of dynamic hand and speed information of the imagined clenching. In particular, the time-varying clenching speed was reconstructed in a bell-shaped profile. Our findings suggest an application to providing continuous and complex control of noninvasive brain-computer interface for movement-impaired paralytics. PMID:20168002

  3. Relationship between speed and EEG activity during imagined and executed hand movements

    NASA Astrophysics Data System (ADS)

    Yuan, Han; Perdoni, Christopher; He, Bin

    2010-04-01

    The relationship between primary motor cortex and movement kinematics has been shown in nonhuman primate studies of hand reaching or drawing tasks. Studies have demonstrated that the neural activities accompanying or immediately preceding the movement encode the direction, speed and other information. Here we investigated the relationship between the kinematics of imagined and actual hand movement, i.e. the clenching speed, and the EEG activity in ten human subjects. Study participants were asked to perform and imagine clenching of the left hand and right hand at various speeds. The EEG activity in the alpha (8-12 Hz) and beta (18-28 Hz) frequency bands were found to be linearly correlated with the speed of imagery clenching. Similar parametric modulation was also found during the execution of hand movements. A single equation relating the EEG activity to the speed and the hand (left versus right) was developed. This equation, which contained a linear independent combination of the two parameters, described the time-varying neural activity during the tasks. Based on the model, a regression approach was developed to decode the two parameters from the multiple-channel EEG signals. We demonstrated the continuous decoding of dynamic hand and speed information of the imagined clenching. In particular, the time-varying clenching speed was reconstructed in a bell-shaped profile. Our findings suggest an application to providing continuous and complex control of noninvasive brain-computer interface for movement-impaired paralytics.

  4. Principal Dynamic Mode Analysis of EEG Data for Assisting the Diagnosis of Alzheimer’s Disease

    PubMed Central

    Escudero, Javier; Shin, Dae; Ifeachor, Emmanuel; Marmarelis, Vasilis

    2015-01-01

    We examine whether modeling of the causal dynamic relationships between frontal and occipital electroencephalogram (EEG) time-series recordings reveal reliable differentiating characteristics of Alzheimer’s patients versus control subjects in a manner that may assist clinical diagnosis of Alzheimer’s disease (AD). The proposed modeling approach utilizes the concept of principal dynamic modes (PDMs) and their associated nonlinear functions (ANF) and hypothesizes that the ANFs of some PDMs for the AD patients will be distinct from their counterparts in control subjects. To this purpose, global PDMs are extracted from 1-min EEG signals of 17 AD patients and 24 control subjects at rest using Volterra models estimated via Laguerre expansions, whereby the O1 or O2 recording is viewed as the input signal and the F3 or F4 recording as the output signal. Subsequent singular value decomposition of the estimated Volterra kernels yields the global PDMs that represent an efficient basis of functions for the representation of the EEG dynamics in all subjects. The respective ANFs are computed for each subject and characterize the specific dynamics of each subject. For comparison, signal features traditionally used in the analysis of EEG signals in AD are computed as benchmark. The results indicate that the ANFs of two specific PDMs, corresponding to the delta–theta and alpha bands, can delineate the two groups well.

  5. Assessment of mental fatigue during car driving by using high resolution EEG activity and neurophysiologic indices.

    PubMed

    Borghini, G; Vecchiato, G; Toppi, J; Astolfi, L; Maglione, A; Isabella, R; Caltagirone, C; Kong, W; Wei, D; Zhou, Z; Polidori, L; Vitiello, S; Babiloni, F

    2012-01-01

    Driving tasks are vulnerable to the effects of sleep deprivation and mental fatigue, diminishing driver's ability to respond effectively to unusual or emergent situations. Physiological and brain activity analysis could help to understand how to provide useful feedback and alert signals to the drivers for avoiding car accidents. In this study we analyze the insurgence of mental fatigue or drowsiness during car driving in a simulated environment by using high resolution EEG techniques as well as neurophysiologic variables such as heart rate (HR) and eye blinks rate (EBR). Results suggest that it is possible to introduce a EEG-based cerebral workload index that it is sensitive to the mental efforts of the driver during drive tasks of different levels of difficulty. Workload index was based on the estimation of increase of EEG power spectra in the theta band over prefrontal areas and the simultaneous decrease of EEG power spectra over parietal areas in alpha band during difficult drive conditions. Such index could be used in a future to assess on-line the mental state of the driver during the drive task. PMID:23367404

  6. Behavioural and EEG effects of chronic rapamycin treatment in a mouse model of tuberous sclerosis complex.

    PubMed

    Cambiaghi, Marco; Cursi, Marco; Magri, Laura; Castoldi, Valerio; Comi, Giancarlo; Minicucci, Fabio; Galli, Rossella; Leocani, Letizia

    2013-04-01

    Tuberous Sclerosis Complex (TSC) is a multisystem genetic disorder caused by mutation in either Tsc1 or Tsc2 genes that leads to the hyper activation of the mTOR pathway, a key signalling pathway for synaptic plasticity. TSC is characterized by benign tumors arising in different organs and severe neuropsychiatric symptoms, such as epilepsy, intellectual disability, autism, anxiety and depressive behaviour. Rapamycin is a potent inhibitor of mTOR and its efficacy in treating epilepsy and neurological symptoms remains elusive. In a mouse model in which Tsc1 has been deleted in embryonic telencephalic neural stem cells, we analyzed anxiety- and depression-like behaviour by elevated-plus maze (EPM), open-field test (OFT), forced-swim test (FST) and tail-suspension test (TST), after chronic administration of rapamycin. In addition, spectral analysis of background EEG was performed. Rapamycin-treated mutant mice displayed a reduction in anxiety- and depression-like phenotype, as shown by the EPM/OFT and FST, respectively. These results were inline with EEG power spectra outcomes. The same effects of rapamycin were observed in wild-type mice. Notably, in heterozygous animals we did not observe any EEG and/or behavioural variation after rapamycin treatment. Together these results suggest that both TSC1 deletion and chronic rapamycin treatment might have a role in modulating behaviour and brain activity, and point out to the potential usefulness of background EEG analysis in tracking brain dysfunction in parallel with behavioural testing. PMID:23159330

  7. Correlation between amygdala BOLD activity and frontal EEG asymmetry during real-time fMRI neurofeedback training in patients with depression.

    PubMed

    Zotev, Vadim; Yuan, Han; Misaki, Masaya; Phillips, Raquel; Young, Kymberly D; Feldner, Matthew T; Bodurka, Jerzy

    2016-01-01

    Real-time fMRI neurofeedback (rtfMRI-nf) is an emerging approach for studies and novel treatments of major depressive disorder (MDD). EEG performed simultaneously with an rtfMRI-nf procedure allows an independent evaluation of rtfMRI-nf brain modulation effects. Frontal EEG asymmetry in the alpha band is a widely used measure of emotion and motivation that shows profound changes in depression. However, it has never been directly related to simultaneously acquired fMRI data. We report the first study investigating electrophysiological correlates of the rtfMRI-nf procedure, by combining the rtfMRI-nf with simultaneous and passive EEG recordings. In this pilot study, MDD patients in the experimental group (n = 13) learned to upregulate BOLD activity of the left amygdala using an rtfMRI-nf during a happy emotion induction task. MDD patients in the control group (n = 11) were provided with a sham rtfMRI-nf. Correlations between frontal EEG asymmetry in the upper alpha band and BOLD activity across the brain were examined. Average individual changes in frontal EEG asymmetry during the rtfMRI-nf task for the experimental group showed a significant positive correlation with the MDD patients' depression severity ratings, consistent with an inverse correlation between the depression severity and frontal EEG asymmetry at rest. The average asymmetry changes also significantly correlated with the amygdala BOLD laterality. Temporal correlations between frontal EEG asymmetry and BOLD activity were significantly enhanced, during the rtfMRI-nf task, for the amygdala and many regions associated with emotion regulation. Our findings demonstrate an important link between amygdala BOLD activity and frontal EEG asymmetry during emotion regulation. Our EEG asymmetry results indicate that the rtfMRI-nf training targeting the amygdala is beneficial to MDD patients. They further suggest that EEG-nf based on frontal EEG asymmetry in the alpha band would be compatible with the amygdala-based rtfMRI-nf. Combination of the two could enhance emotion regulation training and benefit MDD patients. PMID:26958462

  8. Correlation between amygdala BOLD activity and frontal EEG asymmetry during real-time fMRI neurofeedback training in patients with depression

    PubMed Central

    Zotev, Vadim; Yuan, Han; Misaki, Masaya; Phillips, Raquel; Young, Kymberly D.; Feldner, Matthew T.; Bodurka, Jerzy

    2016-01-01

    Real-time fMRI neurofeedback (rtfMRI-nf) is an emerging approach for studies and novel treatments of major depressive disorder (MDD). EEG performed simultaneously with an rtfMRI-nf procedure allows an independent evaluation of rtfMRI-nf brain modulation effects. Frontal EEG asymmetry in the alpha band is a widely used measure of emotion and motivation that shows profound changes in depression. However, it has never been directly related to simultaneously acquired fMRI data. We report the first study investigating electrophysiological correlates of the rtfMRI-nf procedure, by combining the rtfMRI-nf with simultaneous and passive EEG recordings. In this pilot study, MDD patients in the experimental group (n = 13) learned to upregulate BOLD activity of the left amygdala using an rtfMRI-nf during a happy emotion induction task. MDD patients in the control group (n = 11) were provided with a sham rtfMRI-nf. Correlations between frontal EEG asymmetry in the upper alpha band and BOLD activity across the brain were examined. Average individual changes in frontal EEG asymmetry during the rtfMRI-nf task for the experimental group showed a significant positive correlation with the MDD patients' depression severity ratings, consistent with an inverse correlation between the depression severity and frontal EEG asymmetry at rest. The average asymmetry changes also significantly correlated with the amygdala BOLD laterality. Temporal correlations between frontal EEG asymmetry and BOLD activity were significantly enhanced, during the rtfMRI-nf task, for the amygdala and many regions associated with emotion regulation. Our findings demonstrate an important link between amygdala BOLD activity and frontal EEG asymmetry during emotion regulation. Our EEG asymmetry results indicate that the rtfMRI-nf training targeting the amygdala is beneficial to MDD patients. They further suggest that EEG-nf based on frontal EEG asymmetry in the alpha band would be compatible with the amygdala-based rtfMRI-nf. Combination of the two could enhance emotion regulation training and benefit MDD patients. PMID:26958462

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

    PubMed Central

    Fingelkurts, Al. A; Fingelkurts, An. A

    2010-01-01

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

  10. Automated Identification of Abnormal Adult EEGs

    PubMed Central

    López, S.; Suarez, G.; Jungreis, D.; Obeid, I.; Picone, J.

    2016-01-01

    The interpretation of electroencephalograms (EEGs) is a process that is still dependent on the subjective analysis of the examiners. Though interrater agreement on critical events such as seizures is high, it is much lower on subtler events (e.g., when there are benign variants). The process used by an expert to interpret an EEG is quite subjective and hard to replicate by machine. The performance of machine learning technology is far from human performance. We have been developing an interpretation system, AutoEEG, with a goal of exceeding human performance on this task. In this work, we are focusing on one of the early decisions made in this process – whether an EEG is normal or abnormal. We explore two baseline classification algorithms: k-Nearest Neighbor (kNN) and Random Forest Ensemble Learning (RF). A subset of the TUH EEG Corpus was used to evaluate performance. Principal Components Analysis (PCA) was used to reduce the dimensionality of the data. kNN achieved a 41.8% detection error rate while RF achieved an error rate of 31.7%. These error rates are significantly lower than those obtained by random guessing based on priors (49.5%). The majority of the errors were related to misclassification of normal EEGs.

  11. EEG power spectrum changes due to listening to pleasant music and their relation to relaxation effects.

    PubMed

    Kabuto, M; Kageyama, T; Nitta, H

    1993-10-01

    Electroencephalogram (EEG) power spectrum changes induced by pleasant music (2-min. fractions of 6 samples of music [famous classical and commercially available "alpha music" at 10-sec. intervals]) were investigated in relation to changes in 16 kinds of psychosomatic feelings. Subjects were 42 healthy young people aged 18-25 yrs. Two major components, "pleasant & relaxed" and "calm", were extracted through principal component analysis of the feeling changes, both of which were related to the "relaxation effects" of the music. These component scores were not related to the changes of EEG powers in the delta, theta, alpha and beta frequency components in 6 regions (frontal, parietal and occipital regions of the left and right hemispheres), when examined separately. However, the change of the total delta power for all the regions was significantly associated with both the "pleasant & relaxed" and "calm" component scores. The association between the total theta power change and "calm" score was found to be insignificant if the type-A personality variable was added to their regression model. On the other hand, the alpha-peak frequency was inversely related to the decrease of the "calm" score in the left occipital region (LO). The reduction of the alpha-peak power in the LO was also significant, and was associated not with the alpha-peak frequency changes but inversely with the "calm" score, although these alpha-component changes were not shown to be modified by the personality. Thus, the present study suggests, as a preliminary finding, that the "relaxation effects" of pleasant music can be associated with the EEG power spectrum component changes, especially with the change in the total theta power and possibly with that in the alpha power in the occipital, and the frequency shift of the peak in the alpha-range. Some of the associations were also shown to vary for the type-A personality, suggesting a clue to relating the personality to a differential stress-related psychosomatic trait, although the physiological significance of the changes in the low-frequency component range as well as those in the alpha-frequency component, which are obtained through FFT, should be further clarified. PMID:8254987

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

    PubMed Central

    Cannon, Rex L.; Trudeau, David L.

    2008-01-01

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

  13. Asynchronous detection of kinesthetic attention during mobilization of lower limbs using EEG measurements

    NASA Astrophysics Data System (ADS)

    Melinscak, Filip; Montesano, Luis; Minguez, Javier

    2016-02-01

    Objective. Attention is known to modulate the plasticity of the motor cortex, and plasticity is crucial for recovery in motor rehabilitation. This study addresses the possibility of using an EEG-based brain-computer interface (BCI) to detect kinesthetic attention to movement. Approach. A novel experiment emulating physical rehabilitation was designed to study kinesthetic attention. The protocol involved continuous mobilization of lower limbs during which participants reported levels of attention to movement—from focused kinesthetic attention to mind wandering. For this protocol an asynchronous BCI detector of kinesthetic attention and deliberate mind wandering was designed. Main results. EEG analysis showed significant differences in theta, alpha, and beta bands, related to the attentional state. These changes were further pinpointed to bands relative to the frequency of the individual alpha peak. The accuracy of the designed BCI ranged between 60.8% and 68.4% (significantly above chance level), depending on the used analysis window length, i.e. acceptable detection delay. Significance. This study shows it is possible to use self-reporting to study attention-related changes in EEG during continuous mobilization. Such a protocol is used to develop an asynchronous BCI detector of kinesthetic attention, with potential applications to motor rehabilitation.

  14. Chronic exercise alters EEG power spectra in an animal model of depression.

    PubMed

    Sarbadhikari, S N; Dey, S; Ray, A K

    1996-01-01

    The EEG from frontal cortex, EMG and EOG were recorded from rats exposed to only exercise (Treadmill), only stress, exercise + stress and neither (control). In comparison with the control group, the percent of Delta activity in the awake was significantly increased in the depressed group and significantly decreased in the exercised groups, while for Beta-2, the reverse occurred; Theta increased and Beta-2 decreased in the NREM sleep state of the depressed group and the opposite happened for the exercised groups. Delta and Alpha-2 activity significantly increased in the depressed group, and they were significantly decreased in the exercised groups whereas the Beta-2 activity showed contrary changes in the REM sleep state. These findings indicate that exercise has the opposite effect from what stress has on qEEG and concomitant physical exercise reduces the effects of stress. Behavioral tests were done by Open Field (OF) and High Plus Maze (HPM). Slow EEG activity (Delta, Theta, Alpha) was significantly positively correlated with immobilization in the OF and defecation in both OF and HPM and negatively with the food intake, transfer latency in HPM; rearing, grooming and total ambulation in OF Whereas, fast activity (Beta-2) was significantly negatively correlated with immobilization in OF and defecation in OF and HPM, while positively with ambulation in the central squares of OF and time spent at the central cross and number of times arms crossed in the HPM. PMID:8864771

  15. Study on Brain Dynamics by Non Linear Analysis of Music Induced EEG Signals

    NASA Astrophysics Data System (ADS)

    Banerjee, Archi; Sanyal, Shankha; Patranabis, Anirban; Banerjee, Kaushik; Guhathakurta, Tarit; Sengupta, Ranjan; Ghosh, Dipak; Ghose, Partha

    2016-02-01

    Music has been proven to be a valuable tool for the understanding of human cognition, human emotion, and their underlying brain mechanisms. The objective of this study is to analyze the effect of Hindustani music on brain activity during normal relaxing conditions using electroencephalography (EEG). Ten male healthy subjects without special musical education participated in the study. EEG signals were acquired at the frontal (F3/F4) lobes of the brain while listening to music at three experimental conditions (rest, with music and without music). Frequency analysis was done for the alpha, theta and gamma brain rhythms. The finding shows that arousal based activities were enhanced while listening to Hindustani music of contrasting emotions (romantic/sorrow) for all the subjects in case of alpha frequency bands while no significant changes were observed in gamma and theta frequency ranges. It has been observed that when the music stimulus is removed, arousal activities as evident from alpha brain rhythms remain for some time, showing residual arousal. This is analogous to the conventional 'Hysteresis' loop where the system retains some 'memory' of the former state. This is corroborated in the non linear analysis (Detrended Fluctuation Analysis) of the alpha rhythms as manifested in values of fractal dimension. After an input of music conveying contrast emotions, withdrawal of music shows more retention as evidenced by the values of fractal dimension.

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

    PubMed

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

    2014-07-01

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

  17. Distribution entropy analysis of epileptic EEG signals.

    PubMed

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

    2015-08-01

    It is an open-ended challenge to accurately detect the epileptic seizures through electroencephalogram (EEG) signals. Recently published studies have made elaborate attempts to distinguish between the normal and epileptic EEG signals by advanced nonlinear entropy methods, such as the approximate entropy, sample entropy, fuzzy entropy, and permutation entropy, etc. Most recently, a novel distribution entropy (DistEn) has been reported to have superior performance compared with the conventional entropy methods for especially short length data. We thus aimed, in the present study, to show the potential of DistEn in the analysis of epileptic EEG signals. The publicly-accessible Bonn database which consisted of normal, interictal, and ictal EEG signals was used in this study. Three different measurement protocols were set for better understanding the performance of DistEn, which are: i) calculate the DistEn of a specific EEG signal using the full recording; ii) calculate the DistEn by averaging the results for all its possible non-overlapped 5 second segments; and iii) calculate it by averaging the DistEn values for all the possible non-overlapped segments of 1 second length, respectively. Results for all three protocols indicated a statistically significantly increased DistEn for the ictal class compared with both the normal and interictal classes. Besides, the results obtained under the third protocol, which only used very short segments (1 s) of EEG recordings showed a significantly (p <; 0.05) increased DistEn for the interictal class in compassion with the normal class, whereas both analyses using relatively long EEG signals failed in tracking this difference between them, which may be due to a nonstationarity effect on entropy algorithm. The capability of discriminating between the normal and interictal EEG signals is of great clinical relevance since it may provide helpful tools for the detection of a seizure onset. Therefore, our study suggests that the DistEn analysis of EEG signals is very promising for clinical and even portable EEG monitoring. PMID:26737213

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

    PubMed

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

    2014-01-01

    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 μ 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 μ 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 μ-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 μ-beta ERD indexes early predictive coding (e.g., internal modeling) and/or overt and covert attentional/motor processes. μ-alpha ERS may index inhibitory input to the premotor cortex from sensory regions prior to and during discrimination, while μ-alpha ERD may index sensory feedback during speech rehearsal and production. PMID:25071633

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

    PubMed Central

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

    2014-01-01

    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 μ 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 μ 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 μ-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 μ-beta ERD indexes early predictive coding (e.g., internal modeling) and/or overt and covert attentional/motor processes. μ-alpha ERS may index inhibitory input to the premotor cortex from sensory regions prior to and during discrimination, while μ-alpha ERD may index sensory feedback during speech rehearsal and production. PMID:25071633

  20. Time course of EEG oscillations during repeated listening of a well-known aria

    PubMed Central

    Jäncke, Lutz; Kühnis, Jürg; Rogenmoser, Lars; Elmer, Stefan

    2015-01-01

    While previous studies have analyzed mean neurophysiological responses to musical stimuli, the current study aimed to identify specific time courses of electroencephalography (EEG) oscillations, which are associated with dynamic changes in the acoustic features of the musical stimulus. In addition, we were interested in whether these time courses change during a repeated presentation of the same musical piece. A total of 16 subjects repeatedly listened to the well-known aria “Nessun dorma,” sung by Paul Potts, while continuous 128-channel EEG and heart rate, as well as electrodermal responses, were recorded. The time courses for the EEG oscillations were calculated using a time resolution of 1 second for several frequency bands, on the basis of individual alpha-peak frequencies (theta, low alpha-1, low alpha-2, upper alpha, and beta). For all frequency bands, we identified a more or less continuous increase in power relative to a baseline period, indicating strong event-related synchronization (ERS) during music listening. The ERS time courses, however, did not correlate strongly with the time courses of the acoustic features of the aria. In addition, we did not observe changes in EEG oscillations after repeated presentation of the same musical piece. Aside from this distinctive feature, we identified a remarkable variability in EEG oscillations, both within and between the repeated presentations of the aria. We interpret the continuous increase in ERS observed in all frequency bands during music listening as an indicator of a particular neurophysiological and psychological state evoked by music listening. We suggest that this state is characterized by increased internal attention (accompanied by reduced external attention), increased inhibition of brain networks not involved in the generation of this internal state, the maintenance of a particular level of general alertness, and a type of brain state that can be described as “mind wandering.” The overall state can be categorized as a psychological process that may be seen as a “drawing in” to the musical piece. However, this state is not stable and varies considerably throughout the music listening session and across subjects. Most important, however, is the finding that the neurophysiological activations occurring during music listening are dynamic and not stationary. PMID:26257624

  1. Time course of EEG oscillations during repeated listening of a well-known aria.

    PubMed

    Jäncke, Lutz; Kühnis, Jürg; Rogenmoser, Lars; Elmer, Stefan

    2015-01-01

    While previous studies have analyzed mean neurophysiological responses to musical stimuli, the current study aimed to identify specific time courses of electroencephalography (EEG) oscillations, which are associated with dynamic changes in the acoustic features of the musical stimulus. In addition, we were interested in whether these time courses change during a repeated presentation of the same musical piece. A total of 16 subjects repeatedly listened to the well-known aria "Nessun dorma," sung by Paul Potts, while continuous 128-channel EEG and heart rate, as well as electrodermal responses, were recorded. The time courses for the EEG oscillations were calculated using a time resolution of 1 second for several frequency bands, on the basis of individual alpha-peak frequencies (theta, low alpha-1, low alpha-2, upper alpha, and beta). For all frequency bands, we identified a more or less continuous increase in power relative to a baseline period, indicating strong event-related synchronization (ERS) during music listening. The ERS time courses, however, did not correlate strongly with the time courses of the acoustic features of the aria. In addition, we did not observe changes in EEG oscillations after repeated presentation of the same musical piece. Aside from this distinctive feature, we identified a remarkable variability in EEG oscillations, both within and between the repeated presentations of the aria. We interpret the continuous increase in ERS observed in all frequency bands during music listening as an indicator of a particular neurophysiological and psychological state evoked by music listening. We suggest that this state is characterized by increased internal attention (accompanied by reduced external attention), increased inhibition of brain networks not involved in the generation of this internal state, the maintenance of a particular level of general alertness, and a type of brain state that can be described as "mind wandering." The overall state can be categorized as a psychological process that may be seen as a "drawing in" to the musical piece. However, this state is not stable and varies considerably throughout the music listening session and across subjects. Most important, however, is the finding that the neurophysiological activations occurring during music listening are dynamic and not stationary. PMID:26257624

  2. Alpha-theta effects associated with ageing during the Stroop test.

    PubMed

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

    2014-01-01

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

  3. Alpha-Theta Effects Associated with Ageing during the Stroop Test

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2013-02-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    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.

  6. Instantaneous frequency based newborn EEG seizure characterisation

    NASA Astrophysics Data System (ADS)

    Mesbah, Mostefa; O'Toole, John M.; Colditz, Paul B.; Boashash, Boualem

    2012-12-01

    The electroencephalogram (EEG), used to noninvasively monitor brain activity, remains the most reliable tool in the diagnosis of neonatal seizures. Due to their nonstationary and multi-component nature, newborn EEG seizures are better represented in the joint time-frequency domain than in either the time domain or the frequency domain. Characterising newborn EEG seizure nonstationarities helps to better understand their time-varying nature and, therefore, allow developing efficient signal processing methods for both modelling and seizure detection and classification. In this article, we used the instantaneous frequency (IF) extracted from a time-frequency distribution to characterise newborn EEG seizures. We fitted four frequency modulated (FM) models to the extracted IFs, namely a linear FM, a piecewise-linear FM, a sinusoidal FM, and a hyperbolic FM. Using a database of 30-s EEG seizure epochs acquired from 35 newborns, we were able to show that, depending on EEG channel, the sinusoidal and piecewise-linear FM models best fitted 80-98% of seizure epochs. To further characterise the EEG seizures, we calculated the mean frequency and frequency span of the extracted IFs. We showed that in the majority of the cases (>95%), the mean frequency resides in the 0.6-3 Hz band with a frequency span of 0.2-1 Hz. In terms of the frequency of occurrence of the four seizure models, the statistical analysis showed that there is no significant difference( p = 0.332) between the two hemispheres. The results also indicate that there is no significant differences between the two hemispheres in terms of the mean frequency ( p = 0.186) and the frequency span ( p = 0.302).

  7. Automatic classification of athletes with residual functional deficits following concussion by means of EEG signal using support vector machine.

    PubMed

    Cao, Cheng; Tutwiler, Richard Laurence; Slobounov, Semyon

    2008-08-01

    There is a growing body of knowledge indicating long-lasting residual electroencephalography (EEG) abnormalities in concussed athletes that may persist up to 10-year postinjury. Most often, these abnormalities are initially overlooked using traditional concussion assessment tools. Accordingly, premature return to sport participation may lead to recurrent episodes of concussion, increasing the risk of recurrent concussions with more severe consequences. Sixty-one athletes at high risk for concussion (i.e., collegiate rugby and football players) were recruited and underwent EEG baseline assessment. Thirty of these athletes suffered from concussion and were retested at day 30 postinjury. A number of task-related EEG recordings were conducted. A novel classification algorithm, the support vector machine (SVM), was applied as a classifier to identify residual functional abnormalities in athletes suffering from concussion using a multichannel EEG data set. The total accuracy of the classifier using the 10 features was 77.1%. The classifier has a high sensitivity of 96.7% (linear SVM), 80.0% (nonlinear SVM), and a relatively lower but acceptable selectivity of 69.1% (linear SVM) and 75.0% (nonlinear SVM). The major findings of this report are as follows: 1) discriminative features were observed at theta, alpha, and beta frequency bands, 2) the minimal redundancy relevance method was identified as being superior to the univariate t -test method in selecting features for the model calculation, 3) the EEG features selected for the classification model are linked to temporal and occipital areas, and 4) postural parameters influence EEG data set and can be used as discriminative features for the classification model. Overall, this report provides sufficient evidence that 10 EEG features selected for final analysis and SVM may be potentially used in clinical practice for automatic classification of athletes with residual brain functional abnormalities following a concussion episode. PMID:18701381

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

    PubMed

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

    2009-01-01

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

  9. Bilateral EEG differentiation of stimuli.

    PubMed

    Osborne, K; Gale, A

    1976-09-01

    The EEG of both right and left hemispheres was monitored while subjects were presented with words, music, arithmetical problems and abstract pictures, (15 trials of each treatment, 9 sec per trial). The left side of the brain was most activated during presentation of words and arithmetic, whilst the right side of the brain was most activated during presentation of music. In addition, the right side was more activated during exposure to arithmetic than to words. The pictures were not differentiated by either side of the brain and it is possible that they had the effect of deactivating or relaxing subjects, since they yielded high abundance values compared with other stimuli. This study confirms earlier findings showing significant between-hemisphere ratios for arithmetic and words. In addition, however, the within-hemisphere analyses show that music affects the right hemisphere (without inducing between-hemisphere changes) and that arithmetic also activates the right hemisphere if compared with the non-activating effects of words. PMID:963141

  10. [Compressive-spectral analysis of EEG in patients with panic attacks in the context of different psychiatric diseases].

    PubMed

    Tuter, N V; Gnezditski?, V V

    2008-01-01

    Panic disorders (PD) which develop in the context of different psychiatric diseases (neurotic, personality disorder and schizotypal disorders) have their own clinical and neurophysiological features. The results of compressive-spectral analysis of EEG (CSA EEG) in patients with panic attack were different depending on the specifics of initial psychiatric status. EEG parameters in patients differed from those in controls. The common feature for all PD patients was the lower spectral density of theta-, alpha- and beta-bands as well as total spectral density without any alterations of region distribution. The decrease of electrical activity of activation systems was found in the groups with neurotic and schizotypal disorders and that of inhibition systems - in the group with schizotypal disorders. The EEG results did not suggest any depression of activation systems in patients with specific personality disorders. The data obtained with CSA EEG mirror the integrative brain activity which determinad of the appearance of PA as well as of nosology of psychiatre disease. PMID:18427541

  11. Responders to vagus nerve stimulation (VNS) in refractory epilepsy have reduced interictal cortical synchronicity on scalp EEG.

    PubMed

    Bodin, Clémentine; Aubert, Sandrine; Daquin, Géraldine; Carron, Romain; Scavarda, Didier; McGonigal, Aileen; Bartolomei, Fabrice

    2015-07-01

    EEG desynchronization has been proposed to be an important mechanism for antiepileptic effect of vagus nerve stimulation (VNS) but has never been clearly documented in human. The aim of this study was to evaluate impact of VNS on the synchronicity of interictal EEG rhythms. We estimated synchronization between scalp EEG signals using phase lag index (PLI) in 19 patients with chronic VNS therapy. We estimated changes in synchronization between ON and OFF phases and between responder (R) and non-responder (NR) patients. We found that R have a lower global level of synchronization (EEG broadband) than NR (p<0.0001) In addition, ON periods were characterized by lower values in comparison with OFF periods (p<0.001). R had significantly lower global synchronization levels in delta and alpha frequency bands (p<0.0001). Patients responding to VNS have thus a lower level of broadband EEG synchronization than non-responders. Estimating changes of synchronization level is thus a promising tool for predicting response to VNS. PMID:25986196

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

    PubMed Central

    Shim, Jung-Myo; Kim, Sung-Joong

    2014-01-01

    [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. PMID:24764627

  13. Effects and after-effects of chewing gum on vigilance, heart rate, EEG and mood.

    PubMed

    Allen, Andrew P; Jacob, Tim J C; Smith, Andrew P

    2014-06-22

    Research has shown that chewing gum improves attention, although the mechanism for this effect remains unclear. This study investigated the effects and after-effects of chewing gum on vigilance, mood, heart rate and EEG. Participants completed a vigilance task four times; at baseline, with or without chewing gum, and twice post-chewing. EEG alpha and beta power at left frontal and temporal lobes, subjective mood and heart rate were assessed. Chewing gum shortened reaction time and increased the rate of hits, although hits fell during the second post-chewing task. Chewing gum heightened heart rate, but only during chewing. Gum also increased beta power at F7 and T3 immediately post-chewing, but not following the post-chewing tasks. The findings show that chewing gum affects several different indicators of alertness. PMID:24857722

  14. Abnormal EEGs in cognitively and physically healthy oldest old: findings from the 90+ study.

    PubMed

    Peltz, Carrie Brumback; Kim, Howard L; Kawas, Claudia H

    2010-08-01

    People aged 90 years and older (oldest old), the fastest growing segment of the United States population, are known to have high rates of spells of all types, including strokes, transient ischemic attacks, and seizures. This study examined the prevalence of EEG abnormalities in 12 physically and cognitively healthy oldest old (mean age = 94 years) with no history of seizures or spells. Abnormalities were found in 83% of participants: temporal intermittent polymorphic slowing was seen in 67%, background slowing (alpha rhythm <8 Hz) was present in 33%, and temporal intermittent rhythmic delta was found in 17%. The high rates of EEG abnormalities found in these physically and cognitively healthy participants prompt reappraisal of pathologic significance in this unique population. PMID:20634708

  15. Hemispheric specialization of language: an EEG study of bilingual Hopi indian children.

    PubMed

    Rogers, L; TenHouten, W; Kaplan, C D; Gardiner, M

    1977-01-01

    Electroencephalographic (EEG) recordings were obtained from electrode placements over the left and right frontal and parietal lobes of the brain in sixteen Hopi Indian children listening to tape recorded children's stories in the Hopi and English languages. Spectral analysis of the EEG data revealed that, for the parietal leads, alpha desynchronization was relatively greater over the right hemisphere for listening to Hopi than for listening to English, which indicates a greater right hemisphere participation in the processing of the Hopi speech. The results of the experiment are directionally consistent with our hypothesis, and imply that linguistic relativity may exist on a neurolinguistic level, such that languages can differ in the relative degree to which they serve as instruments of thought in a propositional, left hemisphere mode, or in an appositional, right hemisphere mode. PMID:617618

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

    NASA Technical Reports Server (NTRS)

    Bert, J.; Collomb, H.

    1980-01-01

    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.

  17. Integrative Frequency Power of EEG Correlates with Progression of Mild Cognitive Impairment to Dementia in Parkinson's Disease.

    PubMed

    Gu, Youquan; Chen, Jun; Lu, Yaqin; Pan, Suyue

    2016-04-01

    Clinically, predicting the progression of mild cognitive impairment (MCI) and diagnosing dementia in Parkinson's disease (PD) are difficult. This study aims to explore an integrative electroencephalography (EEG) frequency power that could be used to predict the progression of MCI in PD patients. Twenty-six PD patients, in this study, were divided into the mild cognitive impairment group (PDMCI, 17 patients) and dementia group (PDD, 9 patients) according to cognitive performance. Beta peak frequency, alpha relative power, and alpha/theta power were recorded and analyzed for the prediction. Mini Mental State Examination (MMSE) scores at initiation, in the first year, and in the second year were examined. The sensitivity, specificity, positive predictive value, Matthew correlation coefficient, and positive likelihood ratio were calculated in both the integrative EEG biomarkers and single best biomarker. Of the 17 patients with MCI for 2 years, 6 progressed to dementia. Integrative EEG biomarkers, mainly associated with beta peak frequency, can predict conversion from MCI to dementia. These biomarkers had sensitivity of 82% and specificity of 78%, compared with sensitivity of 61% and specificity of 58% of the beta peak frequency. In conclusion, the integrative EEG frequency powers were more sensitive and specific to MCI progression in PD patients. PMID:25519446

  18. Neurofeedback training aimed to improve focused attention and alertness in children with ADHD: a study of relative power of EEG rhythms using custom-made software application.

    PubMed

    Hillard, Brent; El-Baz, Ayman S; Sears, Lonnie; Tasman, Allan; Sokhadze, Estate M

    2013-07-01

    Neurofeedback is a nonpharmacological treatment for attention-deficit hyperactivity disorder (ADHD). We propose that operant conditioning of electroencephalogram (EEG) in neurofeedback training aimed to mitigate inattention and low arousal in ADHD, will be accompanied by changes in EEG bands' relative power. Patients were 18 children diagnosed with ADHD. The neurofeedback protocol ("Focus/Alertness" by Peak Achievement Trainer) has a focused attention and alertness training mode. The neurofeedback protocol provides one for Focus and one for Alertness. This does not allow for collecting information regarding changes in specific EEG bands (delta, theta, alpha, low and high beta, and gamma) power within the 2 to 45 Hz range. Quantitative EEG analysis was completed on each of twelve 25-minute-long sessions using a custom-made MatLab application to determine the relative power of each of the aforementioned EEG bands throughout each session, and from the first session to the last session. Additional statistical analysis determined significant changes in relative power within sessions (from minute 1 to minute 25) and between sessions (from session 1 to session 12). Analysis was of relative power of theta, alpha, low and high beta, theta/alpha, theta/beta, and theta/low beta and theta/high beta ratios. Additional secondary measures of patients' post-neurofeedback outcomes were assessed, using an audiovisual selective attention test (IVA + Plus) and behavioral evaluation scores from the Aberrant Behavior Checklist. Analysis of data computed in the MatLab application, determined that theta/low beta and theta/alpha ratios decreased significantly from session 1 to session 12, and from minute 1 to minute 25 within sessions. The findings regarding EEG changes resulting from brain wave self-regulation training, along with behavioral evaluations, will help elucidate neural mechanisms of neurofeedback aimed to improve focused attention and alertness in ADHD. PMID:23820311

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

    PubMed

    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

    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

  20. Electrical stimulation of the frontal cortex enhances slow-frequency EEG activity and sleepiness.

    PubMed

    D'Atri, A; De Simoni, E; Gorgoni, M; Ferrara, M; Ferlazzo, F; Rossini, P M; De Gennaro, L

    2016-06-01

    Our aim was to enhance the spontaneous slow-frequency EEG activity during the resting state using oscillating transcranial direct currents (tDCS) with a stimulation frequency that resembles the spontaneous oscillations of sleep onset. Accordingly, in this preliminary study, we assessed EEG after-effects of a frontal oscillatory tDCS with different frequency (0.8 vs. 5Hz) and polarity (anodal, cathodal, and sham). Two single-blind experiments compared the after effects on the resting EEG of oscillatory tDCS [Exp. 1=0.8Hz, 10 subjects (26.2±2.5years); Exp. 2=5Hz, 10 subjects (27.4±2.4years)] by manipulating its polarity. EEG signals recorded (28 scalp derivations) before and after stimulation [slow oscillations (0.5-1Hz), delta (1-4Hz), theta (5-7Hz), alpha (8-12Hz), beta 1 (13-15Hz) and beta 2 (16-24Hz)] were compared between conditions as a function of polarity (anodal vs. cathodal vs. sham) and frequency of stimulation (0.8 vs. 5Hz). We found a significant relative enhancement of the delta activity after the anodal tDCS at 5Hz compared to that at 0.8Hz. This increase, even though not reaching the statistical significance compared to sham, is concomitant to a significant increase of subjective sleepiness, as assessed by a visual analog scale. These two phenomena are linearly related with a regional specificity, correlations being restricted to cortical areas perifocal to the stimulation site. We have shown that a frontal oscillating anodal tDCS at 5Hz results in an effective change of both subjective sleepiness and spontaneous slow-frequency EEG activity. These changes are critically associated to both stimulation polarity (anodal) and frequency (5Hz). However, evidence of frequency-dependence seems more unequivocal than evidence of polarity-dependence. PMID:26964682

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

    NASA Astrophysics Data System (ADS)

    Chandran, Vinod

    2012-12-01

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

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

    PubMed Central

    Li, Gang; Chung, Wan-Young

    2014-01-01

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

  3. Estimation of eye closure degree using EEG sensors and its application in driver drowsiness detection.

    PubMed

    Li, Gang; Chung, Wan-Young

    2014-01-01

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

  4. Performance of beamformers on EEG source reconstruction.

    PubMed

    Jon Mohamadi, Yaqub; Poudel, Govinda; Innes, Carrie; Jones, Richard D

    2012-01-01

    Recently a number of new beamformers have been introduced for reconstruction and localization of neural sources from EEG and MEG. However, little is known about the relative performance of these beamformers. In this study, 8 scalar beamformers were examined with respect to several parameters to determine how effective they are at reconstruction of a dipole time course from EEG. A simulated EEG signal was produced by means of forward head modelling for projection of an artificial dipole on scalp electrodes then superimposed on background signal. Both real EEG and white noise were applied as background activity. Although the eigenspace beamformer can perform slightly better than other beamformers for small dipoles, and even more so for large dipoles, it is not a contender for real-time beamforming of EEG as it cannot be completely automated. Overall, in terms of performance, robustness to variations in parameters, and ease of application, the minimum variance and Borgiotti-Kaplan beamformers were found to be the best performers. PMID:23366437

  5. EEG activities during kindling in frog.

    PubMed

    Ono, K; Baba, H; Mori, K; Sato, K

    1980-01-01

    The "kindling" phenomenon was investigated in relation to the EEG activities in frog, Rana nigromaculata. Repetitive electrical stimulation to the unilateral hippocampus produced the following results: (1) Prolongation in duration of after-discharges (AD) and shortening of AD intervals; (2) Appearance and enhancing of spontaneous epileptiform discharges (SEDs), which were suppressed by isolation of hippocampus; (3) Increase in power and duration of background EEG with a specific frequency (9 Hz in the nontreated group and 5 Hz in the hippocampal commissural bisected group), which coincided with the half length of the AO intervals during the steady phase; (4) Marked increase in the late components with peak latencies of 25 and 50 msec in the interhippocampal impulse responses as estimated from the bilateral background hippocampal EEG through an autoregressive model, of which the former only was suppressed by commissural section, while both were suppressed by hippocampal isolation. From the above evidences obtained in frogs, it may be inferred that the brain structures, e.g., thalamus, hypothalamus, reticular formation, etc., play an important role in kindling formation and that the alteration in background EEG generating system during kindling is closely associated with the sporadic epileptiform EEG activities. PMID:7390708

  6. [Status epilepticus: indications for emergency EEG].

    PubMed

    Thomas, P

    1997-11-01

    EEG is a major tool in convulsive status epilepticus. Several techniques may be used, including conventional or digitized EEG using 4, 8, 10 or 16 channels, continuous monitoring with or without simultaneous video recording, and cerebral function monitor. During the first phase, in the emergency ward, EEG may be useful in severe convulsive status epilepticus to assess further evolution and/or prognosis. However, rapid control of seizure at this phase is the primary goal, and optimization of EEG availabilities may lead to more systematic indications. After adequate control of seizures, EEG is mandatory in the following situations: i) a difficult-to-control convulsive status epilepticus, with a high risk of subsequent evolution towards subtle status epilepticus; ii) a resistant status epilepticus which needed high dose of sedatives drugs and/or curarization, to evaluate the level of anaesthesia and to watch for recurrence of epileptiform abnormalities; iii) a permanent, unexplained impairment of consciousness which followed an apparently successful treatment, to detect non convulsive status epilepticus; 4. a doubtful clinical diagnosis, to confirm pseudo-status epilepticus. PMID:9480406

  7. Data selection in EEG signals classification.

    PubMed

    Wang, Shuaifang; Li, Yan; Wen, Peng; Lai, David

    2016-03-01

    The alcoholism can be detected by analyzing electroencephalogram (EEG) signals. However, analyzing multi-channel EEG signals is a challenging task, which often requires complicated calculations and long execution time. This paper proposes three data selection methods to extract representative data from the EEG signals of alcoholics. The methods are the principal component analysis based on graph entropy (PCA-GE), the channel selection based on graph entropy (GE) difference, and the mathematic combinations channel selection, respectively. For comparison purposes, the selected data from the three methods are then classified by three classifiers: the J48 decision tree, the K-nearest neighbor and the Kstar, separately. The experimental results show that the proposed methods are successful in selecting data without compromising the classification accuracy in discriminating the EEG signals from alcoholics and non-alcoholics. Among them, the proposed PCA-GE method uses only 29.69 % of the whole data and 29.5 % of the computation time but achieves a 94.5 % classification accuracy. The channel selection method based on the GE difference also gains a 91.67 % classification accuracy by using only 29.69 % of the full size of the original data. Using as little data as possible without sacrificing the final classification accuracy is useful for online EEG analysis and classification application design. PMID:26733050

  8. Comparison of ictal and interictal EEG signals using fractal features.

    PubMed

    Wang, Yu; Zhou, Weidong; Yuan, Qi; Li, Xueli; Meng, Qingfang; Zhao, Xiuhe; Wang, Jiwen

    2013-12-01

    The feature analysis of epileptic EEG is very significant in diagnosis of epilepsy. This paper introduces two nonlinear features derived from fractal geometry for epileptic EEG analysis. The features of blanket dimension and fractal intercept are extracted to characterize behavior of EEG activities, and then their discriminatory power for ictal and interictal EEGs are compared by means of statistical methods. It is found that there is significant difference of the blanket dimension and fractal intercept between interictal and ictal EEGs, and the difference of the fractal intercept feature between interictal and ictal EEGs is more noticeable than the blanket dimension feature. Furthermore, these two fractal features at multi-scales are combined with support vector machine (SVM) to achieve accuracies of 97.58% for ictal and interictal EEG classification and 97.13% for normal, ictal and interictal EEG classification. PMID:24156671

  9. EEG correlates of fatigue during administration of a neuropsychological test battery

    PubMed Central

    Barwick, Fiona; Arnett, Peter; Slobounov, Semyon

    2011-01-01

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

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

    PubMed

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

    2015-02-01

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

  11. [The reward impact on the performance of verbal creative tasks: behavioral and EEG effects].

    PubMed

    Vol'f, N V; Tarasova, I V

    2013-01-01

    The aim of this study was to compare the effects of stimulating originality verbal instruction (IN1) and monetary reward (IN2) on originality of solutions of a verbal creative task and EEG-correlates of activity, determined on the basis of biopotentials power mapping in the frequency range 4-30 Hz. Right-handed students (10 men and 10 women) took part in experiment. An increase of solutions originality under the influence of monetary reward was revealed. At the promise of monetary reward in comparison with IN1, there was a global increase of the task-related theta2 power. Common to the teta1, 2 and alpha2 bands was increase in hemispheric asymmetry of these rhythms power with higher values in the right hemisphere of the brain. These changes have been observed already in the background EEG after IN2 and testify that generalized changes in hemispheric asymmetry provide the preparatory state after the promise of monetary reward. Regional brain activity changes were associated with beta2 rhythm. Under IN2 in comparison with IN1 the task-related power decreased in all posterior electrode sites except for frontotemporal. Reward-related EEG changes were more typical for men. In men only, promised monetary reward increased theta2 asymmetry and task-induced alpha power. Our results suggest that promise of monetary reward for creative thinking can increase verbal creativity. Gender differences in the reward-related EEG power changes show that men and women differ in neurophysiologic mechanisms that underlie increase of creativity. PMID:23885557

  12. Attention and Working Memory-Related EEG Markers of Subtle Cognitive Deterioration in Healthy Elderly Individuals.

    PubMed

    Deiber, Marie-Pierre; Meziane, Hadj Boumediene; Hasler, Roland; Rodriguez, Cristelle; Toma, Simona; Ackermann, Marine; Herrmann, Franois; Giannakopoulos, Panteleimon

    2015-01-01

    Future treatments of Alzheimer's disease need the identification of cases at high risk at the preclinical stage of the disease before the development of irreversible structural damage. We investigated here whether subtle cognitive deterioration in a population of healthy elderly individuals could be predicted by EEG signals at baseline under cognitive activation. Continuous EEG was recorded in 97 elderly control subjects and 45 age-matched mild cognitive impairment (MCI) cases during a simple attentional and a 2-back working memory task. Upon 18-month neuropsychological follow-up, the final sample included 55 stable (sCON) and 42 deteriorated (dCON) controls. We examined the P1, N1, P3, and PNwm event-related components as well as the oscillatory activities in the theta (4-7?Hz), alpha (8-13?Hz), and beta (14-25?Hz) frequency ranges (ERD/ERS: event-related desynchronization/synchronization, and ITC: inter-trial coherence). Behavioral performance, P1, and N1 components were comparable in all groups. The P3, PNwm, and all oscillatory activity indices were altered in MCI cases compared to controls. Only three EEG indices distinguished the two control groups: alpha and beta ERD (dCON?> ?sCON) and beta ITC (dCON?< ?sCON). These findings show that subtle cognitive deterioration has no impact on EEG indices associated with perception, discrimination, and working memory processes but mostly affects attention, resulting in an enhanced recruitment of attentional resources. In addition, cognitive decline alters neural firing synchronization at high frequencies (14-25?Hz) at early stages, and possibly affects lower frequencies (4-13?Hz) only at more severe stages. PMID:26401557

  13. [Gender-related differences in EEG coherence in Stroop task].

    PubMed

    Bryzgalov, A O; Vol'f, N V

    2006-01-01

    Gender-related differences in EEE coherence were studied in young male and female university students during performance of Stroop task, in which color and word could be congruent or incongruent and spatially integrated or separated. The most clear-cut gender-related differences in the EEG coherence were revealed in the alpha2 and beta frequency bands. In the alpha2 band, gender-related differences in the interhemispheric coherence were associated with spatial characteristics of stimuli: left or right presentation and features of mutual localization of relevant and irrelevant stimuli. These differences were observed when information was addressed to the left hemisphere. Gender-related differences associated with spatial organization of stimuli were also observed for intrahemispheric beta1 coherence. Under conditions of the spatial separation of relevant and irrelevant stimuli, only females demonstrated enhancement of coherence in response to the right-side stimulus presentation as compared to the left-side presentation. It was shown that, during the differentiation of the semantic meaning of verbal stimuli, gender-related differences were caused by the features of integration of beta2 oscillators in the posterior cortical regions. The results are indicative of qualitative gender-related differences in organization of both frontoparietal and lateral attention systems in actualization of selective processes. PMID:17025190

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

    PubMed

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

    2014-01-01

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

  15. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization.

    PubMed

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-01-01

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress. PMID:26286628

  16. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization

    NASA Astrophysics Data System (ADS)

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-08-01

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress.

  17. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization

    PubMed Central

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-01-01

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress. PMID:26286628

  18. Resting-State EEG Delta Power is Associated with Psychological Pain in Adults with a History of Depression

    PubMed Central

    Meerwijk, Esther L.; Ford, Judith M.; Weiss, Sandra J.

    2015-01-01

    Psychological pain is a prominent symptom of clinical depression. We asked if frontal alpha asymmetry, frontal EEG power, and frontal fractal dimension asymmetry predicted psychological pain in adults with a history of depression. Resting-state frontal EEG (F3/F4) was recorded while participants (N=35) sat upright with their eyes closed. Frontal delta power predicted psychological pain while controlling for depressive symptoms, with participants who exhibited less power experiencing greater psychological pain. Frontal fractal dimension asymmetry, a nonlinear measure of complexity, also predicted psychological pain, such that greater left than right complexity was associated with greater psychological pain. Frontal alpha asymmetry did not contribute unique variance to any regression model of psychological pain. As resting-state delta power is associated with the brain’s default mode network, results suggest that the default mode network was less activated during high psychological pain. Findings are consistent with a state of arousal associated with psychological pain. PMID:25600291

  19. Estimating alertness from the EEG power spectrum.

    PubMed

    Jung, T P; Makeig, S; Stensmo, M; Sejnowski, T J

    1997-01-01

    In tasks requiring sustained attention, human alertness varies on a minute time scale. This can have serious consequences in occupations ranging from air traffic control to monitoring of nuclear power plants. Changes in 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. By combining power spectrum estimation, principal component analysis and artificial neural networks, we show that continuous, accurate, noninvasive, and near real-time estimation of an operator's global level of alertness is feasible using EEG measures recorded from as few as two central scalp sites. This demonstration could lead to a practical system for noninvasive monitoring of the cognitive state of human operators in attention-critical settings. PMID:9214784

  20. Developmental Quantitative EEG Differences during Psychomotor Response to Music.

    ERIC Educational Resources Information Center

    Flohr, John W.; Miller, Daniel C.

    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…

  1. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electroencephalogram (EEG) telemetry system. 882... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system consists of transmitters, receivers, and other components used for remotely monitoring or measuring...

  2. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  3. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  4. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electroencephalogram (EEG) telemetry system. 882... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system consists of transmitters, receivers, and other components used for remotely monitoring or measuring...

  5. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electroencephalogram (EEG) telemetry system. 882... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system consists of transmitters, receivers, and other components used for remotely monitoring or measuring...

  6. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  7. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  8. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electroencephalogram (EEG) telemetry system. 882... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system consists of transmitters, receivers, and other components used for remotely monitoring or measuring...

  9. 21 CFR 882.1420 - Electroencephalogram (EEG) signal spectrum analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electroencephalogram (EEG) signal spectrum....1420 Electroencephalogram (EEG) signal spectrum analyzer. (a) Identification. An electroencephalogram (EEG) signal spectrum analyzer is a device used to display the frequency content or power...

  10. 21 CFR 882.1855 - Electroencephalogram (EEG) telemetry system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electroencephalogram (EEG) telemetry system. 882... Electroencephalogram (EEG) telemetry system. (a) Identification. An electroencephalogram (EEG) telemetry system consists of transmitters, receivers, and other components used for remotely monitoring or measuring...

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

    PubMed

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

    2015-12-01

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

  12. Interrater agreement for Critical Care EEG Terminology

    PubMed Central

    Gaspard, Nicolas; Hirsch, Lawrence J.; LaRoche, Suzette M.; Hahn, Cecil D.; Westover, M. Brandon

    2016-01-01

    Summary Objective The interpretation of critical care electroencephalography (EEG) studies is challenging because of the presence of many periodic and rhythmic patterns of uncertain clinical significance. Defining the clinical significance of these patterns requires standardized terminology with high interrater agreement (IRA). We sought to evaluate IRA for the final, published American Clinical Neurophysiology Society (ACNS)–approved version of the critical care EEG terminology (2012 version). Our evaluation included terms not assessed previously and incorporated raters with a broad range of EEG reading experience. Methods After reviewing a set of training slides, 49 readers independently completed a Web-based test consisting of 11 identical questions for each of 37 EEG samples (407 questions). Questions assessed whether a pattern was an electrographic seizure; pattern location (main term 1), pattern type (main term 2); and presence and classification of eight other key features (“plus” modifiers, sharpness, absolute and relative amplitude, frequency, number of phases, fluctuation/evolution, and the presence of “triphasic” morphology). Results IRA statistics (κ values) were almost perfect (90–100%) for seizures, main terms 1 and 2, the +S modifier (superimposed spikes/sharp waves or sharply contoured rhythmic delta activity), sharpness, absolute amplitude, frequency, and number of phases. Agreement was substantial for the +F (superimposed fast activity) and +R (superimposed rhythmic delta activity) modifiers (66% and 67%, respectively), moderate for triphasic morphology (58%), and fair for evolution (21%). Significance IRA for most terms in the ACNS critical care EEG terminology is high. These terms are suitable for multicenter research on the clinical significance of critical care EEG patterns. PMID:24888711

  13. Intracranial EEG potentials estimated from MEG sources: A new approach to correlate MEG and iEEG data in epilepsy.

    PubMed

    Grova, Christophe; Aiguabella, Maria; Zelmann, Rina; Lina, Jean-Marc; Hall, Jeffery A; Kobayashi, Eliane

    2016-05-01

    Detection of epileptic spikes in MagnetoEncephaloGraphy (MEG) requires synchronized neuronal activity over a minimum of 4cm2. We previously validated the Maximum Entropy on the Mean (MEM) as a source localization able to recover the spatial extent of the epileptic spike generators. The purpose of this study was to evaluate quantitatively, using intracranial EEG (iEEG), the spatial extent recovered from MEG sources by estimating iEEG potentials generated by these MEG sources. We evaluated five patients with focal epilepsy who had a pre-operative MEG acquisition and iEEG with MRI-compatible electrodes. Individual MEG epileptic spikes were localized along the cortical surface segmented from a pre-operative MRI, which was co-registered with the MRI obtained with iEEG electrodes in place for identification of iEEG contacts. An iEEG forward model estimated the influence of every dipolar source of the cortical surface on each iEEG contact. This iEEG forward model was applied to MEG sources to estimate iEEG potentials that would have been generated by these sources. MEG-estimated iEEG potentials were compared with measured iEEG potentials using four source localization methods: two variants of MEM and two standard methods equivalent to minimum norm and LORETA estimates. Our results demonstrated an excellent MEG/iEEG correspondence in the presumed focus for four out of five patients. In one patient, the deep generator identified in iEEG could not be localized in MEG. MEG-estimated iEEG potentials is a promising method to evaluate which MEG sources could be retrieved and validated with iEEG data, providing accurate results especially when applied to MEM localizations. Hum Brain Mapp 37:1661-1683, 2016. © 2016 Wiley Periodicals, Inc. PMID:26931511

  14. Memory load effect in auditory-verbal short-term memory task: EEG fractal and spectral analysis.

    PubMed

    Stokić, Miodrag; Milovanović, Dragan; Ljubisavljević, Miloš R; Nenadović, Vanja; Čukić, Milena

    2015-10-01

    The objective of this preliminary study was to quantify changes in complexity of EEG using fractal dimension (FD) alongside linear methods of spectral power, event-related spectral perturbations, coherence, and source localization of EEG generators for theta (4-7 Hz), alpha (8-12 Hz), and beta (13-23 Hz) frequency bands due to a memory load effect in an auditory-verbal short-term memory (AVSTM) task for words. We examined 20 healthy individuals using the Sternberg's paradigm with increasing memory load (three, five, and seven words). The stimuli were four-letter words. Artifact-free 5-s EEG segments during retention period were analyzed. The most significant finding was the increase in FD with the increase in memory load in temporal regions T3 and T4, and in parietal region Pz, while decrease in FD with increase in memory load was registered in frontal midline region Fz. Results point to increase in frontal midline (Fz) theta spectral power, decrease in alpha spectral power in parietal region-Pz, and increase in beta spectral power in T3 and T4 region with increase in memory load. Decrease in theta coherence within right hemisphere due to memory load was obtained. Alpha coherence increased in posterior regions with anterior decrease. Beta coherence increased in fronto-temporal regions. Source localization delineated theta activity increase in frontal midline region, alpha decrease in superior parietal region, and beta increase in superior temporal gyrus with increase in memory load. In conclusion, FD as a nonlinear measure may serve as a sensitive index for quantifying dynamical changes in EEG signals during AVSTM tasks. PMID:26169106

  15. Evoked potentials and EEG in multiple sclerosis.

    PubMed

    Pakalnis, A; Drake, M E; Dadmehr, N; Weiss, K

    1987-10-01

    Thirteen patients with clinically definite multiple sclerosis (MS) were studied with electroencephalogram (EEG), magnetic resonance imaging (MRI), evoked potentials and cerebrospinal fluid (CSF) analysis. We attempted to correlate the findings with physical disability as defined by Kurtzke score and presence of dementia or seizures. More severe plaque disease on MRI and increased physical disability correlated significantly with abnormality on brain-stem auditory evoked potentials (BAEPs) while visual evoked potential (VEP) abnormality correlated only with MRI findings. No such correlation was found with the EEG. The close relationship between BAEP and MRI abnormalities probably reflects frequent involvement of brain-stem corticospinal pathways. PMID:2441967

  16. The processing and transmission of EEG data

    NASA Technical Reports Server (NTRS)

    Schulze, A. E.

    1974-01-01

    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.

  17. An approach for representing EEG activity.

    PubMed

    Gruner, P; Otto, E

    1985-09-01

    A method for the representation of EEG-parameters by means of a bidimensional plot of two signals is described. A block diagram is given for the recording of figures with phase-sensitive parameter variations, using an oscilloscope or an X-Y graphic recorder as a display. Charts for the determination of the setting parameters of a digital as well as an analog phase-shifting arrangement are submitted. The method is capable of reflecting individual properties of a single wave and typical characteristics of the epoch as well. It is felt that it may be of benefit in the immediate estimation of EEG-activity changes. PMID:4060990

  18. Fractal Dimension in Epileptic EEG Signal Analysis

    NASA Astrophysics Data System (ADS)

    Uthayakumar, R.

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

  19. Which EEG patterns in coma are nonconvulsive status epilepticus?

    PubMed

    Trinka, Eugen; Leitinger, Markus

    2015-08-01

    Nonconvulsive status epilepticus (NCSE) is common in patients with coma with a prevalence between 5% and 48%. Patients in deep coma may exhibit epileptiform EEG patterns, such as generalized periodic spikes, and there is an ongoing debate about the relationship of these patterns and NCSE. The purposes of this review are (i) to discuss the various EEG patterns found in coma, its fluctuations, and transitions and (ii) to propose modified criteria for NCSE in coma. Classical coma patterns such as diffuse polymorphic delta activity, spindle coma, alpha/theta coma, low output voltage, or burst suppression do not reflect NCSE. Any ictal patterns with a typical spatiotemporal evolution or epileptiform discharges faster than 2.5 Hz in a comatose patient reflect nonconvulsive seizures or NCSE and should be treated. Generalized periodic diacharges or lateralized periodic discharges (GPDs/LPDs) with a frequency of less than 2.5 Hz or rhythmic discharges (RDs) faster than 0.5 Hz are the borderland of NCSE in coma. In these cases, at least one of the additional criteria is needed to diagnose NCSE (a) subtle clinical ictal phenomena, (b) typical spatiotemporal evolution, or (c) response to antiepileptic drug treatment. There is currently no consensus about how long these patterns must be present to qualify for NCSE, and the distinction from nonconvulsive seizures in patients with critical illness or in comatose patients seems arbitrary. The Salzburg Consensus Criteria for NCSE [1] have been modified according to the Standardized Terminology of the American Clinical Neurophysiology Society [2] and validated in three different cohorts, with a sensitivity of 97.2%, a specificity of 95.9%, and a diagnostic accuracy of 96.3% in patients with clinical signs of NCSE. Their diagnostic utility in different cohorts with patients in deep coma has to be studied in the future. This article is part of a Special Issue entitled "Status Epilepticus". PMID:26148985

  20. Automatic sleep onset detection using single EEG sensor.

    PubMed

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

    2014-01-01

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

  1. Entrainment of Human Alpha Oscillations Selectively Enhances Visual Conjunction Search

    PubMed Central

    Müller, Notger G.; Vellage, Anne-Katrin; Heinze, Hans-Jochen; Zaehle, Tino

    2015-01-01

    The functional role of the alpha-rhythm which dominates the human electroencephalogram (EEG) is unclear. It has been related to visual processing, attentional selection and object coherence, respectively. Here we tested the interaction of alpha oscillations of the human brain with visual search tasks that differed in their attentional demands (pre-attentive vs. attentive) and also in the necessity to establish object coherence (conjunction vs. single feature). Between pre- and post-assessment elderly subjects received 20 min/d of repetitive transcranial alternating current stimulation (tACS) over the occipital cortex adjusted to their individual alpha frequency over five consecutive days. Compared to sham the entrained alpha oscillations led to a selective, set size independent improvement in the conjunction search task performance but not in the easy or in the hard feature search task. These findings suggest that cortical alpha oscillations play a specific role in establishing object coherence through suppression of distracting objects. PMID:26606255

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

    PubMed Central

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

    2014-01-01

    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

  3. Simultaneous EEG-fMRI brain signatures of auditory cue utilization

    PubMed Central

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

    2014-01-01

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

  4. Spectral and brain mapping analysis of EEG based on Pwelch in schizophrenic patients

    NASA Astrophysics Data System (ADS)

    Akbar, Y.; Khotimah, S. N.; Haryanto, F.

    2016-03-01

    The aim of this study is to investigate and analyze the differences of power spectral distribution in various frequency bands between healthy subjects and schizophrenic patients. Subjects in this study were 8 people consisting of 4 schizophrenic patients and 4 healthy subjects. Subjects were recorded from 12 electrodes with Electroencephalography (EEG). EEG signals were recorded during a resting eye-closed state for 4-6 minutes. Data were extracted and analyzed by centering and filtering, then performed using Welch Periodogram technique for the spectral estimation with a Hamming window. The results of this study showed that delta power spectral in schizophrenic patients increased ten times from healthy subjects; theta power spectral in schizophrenic patients increased three times from healthy subjects; alpha power spectral in schizophrenic patients decreased with an increase of one third of healthy subjects. These results were confirmed by Kolmogorov-Smirnov test showing there were significant differences between schizophrenic and healthy subjects on delta, theta and alpha brain wave. Based on the results of Brain Mapping analysis showed that there was significant increasing in the activity of delta waves and theta waves in frontal lobe of schizophrenics, whereas the alpha waves indicated a decrease in the occipital lobe in all schizophrenic patients.

  5. Complex network analysis of resting state EEG in amnestic mild cognitive impairment patients with type 2 diabetes

    PubMed Central

    Zeng, Ke; Wang, Yinghua; Ouyang, Gaoxiang; Bian, Zhijie; Wang, Lei; Li, Xiaoli

    2015-01-01

    Purpose: Diabetes is a great risk factor for dementia and mild cognitive impairment (MCI). This study investigates whether complex network-derived features in resting state EEG (rsEEG) could be applied as a biomarker to distinguish amnestic mild cognitive impairment (aMCI) from normal cognitive function in subjects with type 2 diabetes (T2D). Method: In this study, EEG was recorded in 28 patients with T2D (16 aMCI patients and 12 controls) during a no-task eyes-closed resting state. Pair-wise synchronization of rsEEG signals were assessed in six frequency bands (delta, theta, lower alpha, upper alpha, beta, and gamma) using phase lag index (PLI) and grouped into long distance (intra- and inter-hemispheric) and short distance interactions. PLI-weighted connectivity networks were also constructed, and characterized by mean clustering coefficient and path length. The correlation of these features and Montreal Cognitive Assessment (MoCA) scores was assessed. Results: Main findings of this study were as follows: (1) In comparison with controls, patients with aMCI had a significant decrease of global mean PLI in lower alpha, upper alpha, and beta bands. Lower functional connection at short and long intra-hemispheric distance mainly appeared on the left hemisphere. (2) In the lower alpha band, clustering coefficient was significantly lower in aMCI group, and the path length significantly increased. (3) Cognitive status measured by MoCA had a significant positive correlation with cluster coefficient and negative correlation with path length in lower alpha band. Conclusions: The brain network of aMCI patients displayed a disconnection syndrome and a loss of small-world architecture. The correlation between cognitive states and network characteristics suggested that the more in deterioration of the diabetes patients' cognitive state, the less optimal the network organization become. Hence, the complex network-derived biomarkers based on EEG could be employed to track cognitive function of diabetic patients and provide a new diagnosis tool for aMCI. PMID:26578946

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

    PubMed Central

    2012-01-01

    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. PMID:22364485

  7. A systematic review of the neurophysiology of mindfulness on EEG oscillations.

    PubMed

    Lomas, Tim; Ivtzan, Itai; Fu, Cynthia H Y

    2015-10-01

    Mindfulness meditation has been purported to be a beneficial practice for wellbeing. It would therefore be expected that the neurophysiology of mindfulness would reflect this impact on wellbeing. However, investigations of the effects of mindfulness have generated mixed reports of increases, decreases, as well as no differences in EEG oscillations in comparison with a resting state and a variety of tasks. We have performed a systematic review of EEG studies of mindfulness meditation in order to determine any common effects and to identify factors which may impact on the effects. Databases were reviewed from 1966 to August 2015. Eligibility criteria included empirical quantitative analyses of mindfulness meditation practice and EEG measurements acquired in relation to practice. A total of 56 papers met the eligibility criteria and were included in the systematic review, consisting of a total 1715 subjects: 1358 healthy individuals and 357 individuals with psychiatric diagnoses. Studies were principally examined for power outcomes in each bandwidth, in particular the power differentials between mindfulness and a control state, as well as outcomes relating to hemispheric asymmetry and event-related potentials. The systematic review revealed that mindfulness was most commonly associated with enhanced alpha and theta power as compared to an eyes closed resting state, although such outcomes were not uniformly reported. No consistent patterns were observed with respect to beta, delta and gamma bandwidths. In summary, mindfulness is associated with increased alpha and theta power in both healthy individuals and in patient groups. This co-presence of elevated alpha and theta may signify a state of relaxed alertness which is conducive to mental health. PMID:26441373

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

    PubMed

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

    2015-02-01

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

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

    PubMed

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

    2015-01-15

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

  10. Alpha oscillatory correlates of motor inhibition in the aged brain

    PubMed Central

    Bönstrup, Marlene; Hagemann, Julian; Gerloff, Christian; Sauseng, Paul; Hummel, Friedhelm C.

    2015-01-01

    Exerting inhibitory control is a cognitive ability mediated by functions known to decline with age. The goal of this study is to add to the mechanistic understanding of cortical inhibition during motor control in aged brains. Based on behavioral findings of impaired inhibitory control with age we hypothesized that elderly will show a reduced or a lack of EEG alpha-power increase during tasks that require motor inhibition. Since inhibitory control over movements has been shown to rely on prior motor memory formation, we investigated cortical inhibitory processes at two points in time—early after learning and after an overnight consolidation phase and hypothesized an overnight increase of inhibitory capacities. Young and elderly participants acquired a complex finger movement sequence and in each experimental session brain activity during execution and inhibition of the sequence was recorded with multi-channel EEG. We assessed cortical processes of sustained inhibition by means of task-induced changes of alpha oscillatory power. During inhibition of the learned movement, young participants showed a significant alpha power increase at the sensorimotor cortices whereas elderly did not. Interestingly, for both groups, the overnight consolidation phase improved up-regulation of alpha power during sustained inhibition. This points to deficits in the generation and enhancement of local inhibitory mechanisms at the sensorimotor cortices in aged brains. However, the alpha power increase in both groups implies neuroplastic changes that strengthen the network of alpha power generation over time in young as well as elderly brains. PMID:26528179

  11. Influence of the earth's magnetic field on resting and activated EEG mapping in normal subjects.

    PubMed

    Ruhenstroth-Bauer, G; Günther, W; Hantschk, I; Klages, U; Kugler, J; Peters, J

    1993-12-01

    We found in a former investigation that by measuring sleep parameters, the REM latency is shortened in the E-W position of sleepers compared with the N-S position. This paper reports on a further neurological observation in humans concerning the influence of the earth's magnetic field: there are statistically significant differences in the EEG of normal subjects, depending on whether the subjects sit facing the N-S or E-W direction. The difference is especially pronounced in the alpha-power. PMID:8169054

  12. Classification of awake, REM, and NREM from EEG via singular spectrum analysis.

    PubMed

    Mohammadi, Sara Mahvash; Enshaeifar, Shirin; Ghavami, Mohammad; Sanei, Saeid

    2015-08-01

    In this study, a single-channel electroencephalography (EEG) analysis method has been proposed for automated 3-state-sleep classification to discriminate Awake, NREM (non-rapid eye movement) and REM (rapid eye movement). For this purpose, singular spectrum analysis (SSA) is applied to automatically extract four brain rhythms: delta, theta, alpha, and beta. These subbands are then used to generate the appropriate features for sleep classification using a multi class support vector machine (M-SVM). The proposed method provided 0.79 agreement between the manual and automatic scores. PMID:26737360

  13. Dynamic clustering for vigilance analysis based on EEG.

    PubMed

    Shi, Li-Chen; Lu, Bao-Liang

    2008-01-01

    Electroencephalogram (EEG) is the most commonly studied signal for vigilance estimation. Up to now, many researches mainly focus on using supervised learning methods for analyzing EEG data. However, it is hard to obtain enough labeled EEG data to cover the whole vigilance states, and sometimes the labeled EEG data may be not reliable in practice. In this paper, we propose a dynamic clustering method based on EEG to estimate vigilance states. This method uses temporal series information to supervise EEG data clustering. Experimental results show that our method can correctly discriminate between the wakefulness and the sleepiness for every 2 seconds through EEG, and can also distinguish two other middle states between wakefulness and sleepiness. PMID:19162592

  14. EEG correlates of enhanced spatial performance following exposure to music.

    PubMed

    Rideout, B E; Laubach, C M

    1996-04-01

    Previous research has shown that exposure to classical music can influence performance on a spatial task. The present study investigated EEG correlates of this enhanced performance effect, 4 female and 4 male undergraduates completed two equivalent spatial tests, one following a control procedure and one following the presentation of Mozart's Sonata for Two Pianos in D Major. EEG was recorded during a baseline and two task-performance periods. Test performance and EEG recordings were analyzed, and correlations were generated between task performance and EEG variables (average spectral power and peak frequency within 5 frequency ranges). Performance improved significantly following the presentation of the music. EEG analysis indicated 6 reliable correlations out of 40 calculated between differential EEG variables and changes in performance. Ten reliable correlations out of 120 were also found between changes in performance and nondifferential EEG variables across baseline, control, and experimental conditions. PMID:8724912

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

    PubMed Central

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

    2014-01-01

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

  16. Music Shifts Frontal EEG in Depressed Adolescents.

    ERIC Educational Resources Information Center

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

    1998-01-01

    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

  17. Music Shifts Frontal EEG in Depressed Adolescents.

    ERIC Educational Resources Information Center

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

    1998-01-01

    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…

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

    SciTech Connect

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

    2015-01-15

    The electroencephalogram (EEG) is an apical measure, capable of detecting changes in brain neuronal activity produced by internal or external stimuli. We assessed whether pesticides with different modes of action produced different changes in the EEG of adult male Long–Evans rats. The EEG was recorded using two montages (visual cortex referenced to the cerebellum and to the frontal cortex) in unrestrained rats at the time of peak behavioral effects. Pesticides included: permethrin and deltamethrin (Type I and Type II pyrethroids; 2 h), fipronil (single and repeated doses; phenylpyrazole; 6 h), imidacloprid (neonicotinoid; 2 h), carbaryl (carbamate; 0.5 h), and triadimefon (triazole; 1 h), using dosages that produced approximately an ED{sub 30} or an ED{sub 50}–ED{sub 80} change in motor activity. Permethrin (43, 100 mg/kg) increased amplitudes or areas (delta, alpha, or gamma bands) in the EEG. Deltamethrin (2.5, 5.5 mg/kg) reduced the amplitudes or areas of the delta, theta, alpha, beta, and gamma bands, but the changes were not dose-related. A single treatment with fipronil (25, 50 mg/kg, but not 5, 10 mg/kg) decreased gamma band area. Additional changes in the delta, theta, and gamma bands were observed when fipronil (5, 10 mg/kg) was administered for 14 days. Imidacloprid (50, 100 mg/kg) did not alter the EEG. Carbaryl (10, 50 mg/kg) decreased theta area, and decreased delta and increased beta frequency. Triadimefon (75, 150 mg/kg) produced minimal changes in the EEG. The results show that the EEG is affected differently by approximately equipotent doses of pesticides with different modes of action. - Highlights: • Pesticides with different modes of action have different effects on in vivo rodent EEG. • The EEG was also changed differently after single vs. repeated treatment with fipronil. • The data suggest that EEG may be used as an apical measure for detecting chemical effects on the central nervous system.

  19. EEG findings in frontal lobe epilepsies.

    PubMed

    Bautista, R E; Spencer, D D; Spencer, S S

    1998-06-01

    As a group, epilepsies of frontal lobe origin are thought to be poorly localized using surface EEG recordings. This finding may depend on the specific areas of frontal lobe from which the seizures originate or the pathologic substrate. We reviewed the presurgical surface EEGs of patients with frontal lobe epilepsy who underwent epilepsy surgery. The specific area of the frontal lobe where seizures originated was determined by 1) intracranial ictal EEG recordings, or 2) the presence of a structural lesion, identified by imaging studies in patients who achieved complete seizure control following surgery. We differentiated patients whose seizures began in the dorsolateral frontal convexity from those whose seizures began in the medial frontal region, and we correlated EEG findings in the interictal, postictal, and ictal states with seizure semiology, pathologic substrate, and surgical outcome. Four of nine patients had seizures originating in the dorsolateral frontal convexity and five had medial frontal onset seizures. Patients whose seizures originated from the dorsolateral convexity had focal interictal epileptiform abnormalities that localized to the region of seizure onset. Patients whose seizures began in the medial frontal region had either no interictal epileptiform abnormality or had multifocal epileptiform discharges. Patients whose seizures began in the dorsolateral convexity showed focal electrographic seizure activity that was localizing. This rhythmic fast activity did not appear to be substrate-specific. Patients whose seizure onset localized to the medial frontal region did not show focal electrographic seizure at clinical onset. We conclude that the scalp EEG recordings of frontal lobe epilepsies contain features that enable differentiation of seizures originating from two different regions of the frontal lobe. PMID:9633725

  20. Psychometric and EEG changes after carotid endarterectomy.

    PubMed

    Valenti, Pietro; Ortelli, Paola; Zanon, Antonio; Schiff, Sami; Montagnese, Sara; Avruscio, Giampietro; Del Piccolo, Franco; Mapelli, Daniela; Puato, Massimo; Rattazzi, Marcello; Amodio, Piero; Pauletto, Paolo

    2015-02-01

    The influence of carotid stenosis and its surgical treatment on brain function is still poorly defined. We therefore performed a study to assess psychometric and quantified EEG findings after carotid endarterectomy (CEA). Sixty-nine non-demented patients (aged 72 ± 7 years) with severe carotid stenosis (≥ 70%) eligible for CEA were studied. Forty patients (group A) had unilateral stenosis, and 29 patients (group B) had bilateral stenosis. Before and 5 months after CEA all the patients were evaluated by the Trail Making Test A, the Symbol Digit Test, and spectral EEG analysis. At baseline, compared to group A, group B patients performed slowly the Trail Making Test A (Z: 1.45 ± 1.4 vs. 0.76 ± 1.3; p <  0.05), but not the Symbol Digit Test (Z: 0.83 ± 1.38 vs. 0.64 ± 1.26; p = 0.59). Altogether, the patients with at least one abnormal psychometric test were 29% (group A: 26%; group B: 33%, p = 0.56). The EEG did not differ significantly between patients of group A compared to group B. After CEA, psychometric tests improved (mean Z score from 0.73 ± 1.12 to 0.45 ± 1.15, p <  0.05). The improvement was similar in group A and B. The EEG mean dominant frequency improved only in group B patients and it was related to the improvement in psychometric tests (r = 0.43, p = 0.05). Low psychometric performance was detectable in about 1/ 3 of non-demented patients with severe carotid stenosis. CEA improved mental performance and, in patients with severe bilateral stenosis, accelerated the EEG frequency. PMID:25034456

  1. Effets des radiofréquences sur le système nerveux central chez lʼhomme : EEG, sommeil, cognition, vascularisation

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    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.

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

    PubMed

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

    2012-01-01

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

  3. Correlated components of ongoing EEG point to emotionally laden attention - a possible marker of engagement?

    PubMed

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

    2012-01-01

    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. PMID:22623915

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

    PubMed Central

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

    2014-01-01

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

  5. Dynamical complexity in a mean-field model of human EEG

    NASA Astrophysics Data System (ADS)

    Frascoli, Federico; Dafilis, Mathew P.; van Veen, Lennaert; Bojak, Ingo; Liley, David T. J.

    2008-12-01

    A recently proposed mean-field theory of mammalian cortex rhythmogenesis describes the salient features of electrical activity in the cerebral macrocolumn, with the use of inhibitory and excitatory neuronal populations (Liley et al 2002). This model is capable of producing a range of important human EEG (electroencephalogram) features such as the alpha rhythm, the 40 Hz activity thought to be associated with conscious awareness (Bojak & Liley 2007) and the changes in EEG spectral power associated with general anesthetic effect (Bojak & Liley 2005). From the point of view of nonlinear dynamics, the model entails a vast parameter space within which multistability, pseudoperiodic regimes, various routes to chaos, fat fractals and rich bifurcation scenarios occur for physiologically relevant parameter values (van Veen & Liley 2006). The origin and the character of this complex behaviour, and its relevance for EEG activity will be illustrated. The existence of short-lived unstable brain states will also be discussed in terms of the available theoretical and experimental results. A perspective on future analysis will conclude the presentation.

  6. Soft, comfortable polymer dry electrodes for high quality ECG and EEG recording.

    PubMed

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

    2014-01-01

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

  7. Correlated Components of Ongoing EEG Point to Emotionally Laden Attention – A Possible Marker of Engagement?

    PubMed Central

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

    2012-01-01

    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. PMID:22623915

  8. Non-linear analysis of EEG and HRV signals during sleep.

    PubMed

    Martin, Alejandro; Guerrero-Mora, Guillermina; Dorantes-Mendez, Guadalupe; Alba, Alfonso; Mendez, Martin O; Chouvarda, Ioanna

    2015-08-01

    The sleep phenomenon is a complex process that involves fluctuations of autonomic functions such as the blood pressure, temperature and brain function. These fluctuations change their properties through the different sleep stages with specific relations among the different systems. In order to understand the relation between the cardiovascular and central nervous system at the different sleep stages, we applied different non-linear methods to the energy of electroencephalographic signal (EEG) and the heart rate fluctuations. The EEG was divided in the Delta, Theta, Alpha and Beta frequency bands and the mean energy of these bands was computed at each heart rate interval. Thus, the non-linear relation was evaluated between the energy of the EEG bands and the heart rate fluctuations using Cross-Correlation, Cross-Sample Entropy and Recurrence Quantification Analysis in segments of 5 minutes grouped by sleep stage. The results showed that a relation exists between the changes of the energy in the Delta band and the Heart rate fluctuations. PMID:26737214

  9. Stress assessment based on EEG univariate features and functional connectivity measures.

    PubMed

    Alonso, J F; Romero, S; Ballester, M R; Antonijoan, R M; Maanas, M A

    2015-07-01

    The biological response to stress originates in the brain but involves different biochemical and physiological effects. Many common clinical methods to assess stress are based on the presence of specific hormones and on features extracted from different signals, including electrocardiogram, blood pressure, skin temperature, or galvanic skin response. The aim of this paper was to assess stress using EEG-based variables obtained from univariate analysis and functional connectivity evaluation. Two different stressors, the Stroop test and sleep deprivation, were applied to 30 volunteers to find common EEG patterns related to stress effects. Results showed a decrease of the high alpha power (11 to 12?Hz), an increase in the high beta band (23 to 36?Hz, considered a busy brain indicator), and a decrease in the approximate entropy. Moreover, connectivity showed that the high beta coherence and the interhemispheric nonlinear couplings, measured by the cross mutual information function, increased significantly for both stressors, suggesting that useful stress indexes may be obtained from EEG-based features. PMID:26015439

  10. EEG-Based Subject- and Session-independent Drowsiness Detection: An Unsupervised Approach

    NASA Astrophysics Data System (ADS)

    Pal, Nikhil R.; Chuang, Chien-Yao; Ko, Li-Wei; Chao, Chih-Feng; Jung, Tzyy-Ping; Liang, Sheng-Fu; Lin, Chin-Teng

    2008-12-01

    Monitoring and prediction of changes in the human cognitive states, such as alertness and drowsiness, using physiological signals are very important for driver's safety. Typically, physiological studies on real-time detection of drowsiness usually use the same model for all subjects. However, the relatively large individual variability in EEG dynamics relating to loss of alertness implies that for many subjects, group statistics may not be useful to accurately predict changes in cognitive states. Researchers have attempted to build subject-dependent models based on his/her pilot data to account for individual variability. Such approaches cannot account for the cross-session variability in EEG dynamics, which may cause problems due to various reasons including electrode displacements, environmental noises, and skin-electrode impedance. Hence, we propose an unsupervised subject- and session-independent approach for detection departure from alertness in this study. Experimental results showed that the EEG power in the alpha-band (as well as in the theta-band) is highly correlated with changes in the subject's cognitive state with respect to drowsiness as reflected through his driving performance. This approach being an unsupervised and session-independent one could be used to develop a useful system for noninvasive monitoring of the cognitive state of human operators in attention-critical settings.

  11. The Role of Epilepsy and Epileptiform EEGs in Autism Spectrum Disorders

    PubMed Central

    Spence, Sarah J; Schneider, Mark T

    2009-01-01

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

  12. Alpha-1 Antitrypsin Test

    MedlinePlus

    ... helpful? Also known as: Alpha 1 -antitrypsin; A1AT; AAT Formal name: Alpha 1 Antitrypsin; α1-antitrypsin Related ... know? How is it used? Alpha-1 antitrypsin (AAT) testing is used to help diagnose alpha-1 ...

  13. Lasting modulation effects of rTMS on neural activity and connectivity as revealed by resting-state EEG.

    PubMed

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

    2014-07-01

    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

  14. Interhemispheric Asymmetries and Theta Activity in the Rostral Anterior Cingulate Cortex as EEG Signature of HIV-Related Depression: Gender Matters.

    PubMed

    Kremer, Heidemarie; Lutz, Franz P C; McIntosh, Roger C; Dévieux, Jessy G; Ironson, Gail

    2016-04-01

    Resting EEGs of 40 people living with HIV (PLWH) on long-term antiretroviral treatment were examined for z-scored deviations from a healthy control (normative database) to examine the main and interaction effects of depression and gender. Regions of interest were frontal (alpha) and central (all bands) for interhemispheric asymmetries in quantitative EEGs and theta in the rostral anterior cingulate cortex (rACC) in low-resolution electromagnetic tomography (LORETA). Z-scored normed deviations of depressed PLWH, compared with nondepressed, showed right-dominant interhemispheric asymmetries in all regions. However, after adjusting for multiple testing, significance remained only central for theta, alpha, and beta. Reversed (left-dominant) frontal alpha asymmetry is a potential EEG marker of depression in the HIV negative population that was not reversed in depressive PLWH; however, corresponding with extant literature, gender had an effect on the size of frontal alpha asymmetry. The LORETA analysis revealed a trending interactional effect of depression and gender on theta activity in the rACC in Brodmann area 32. We found that compared to men, women had greater right-dominant frontal alpha-asymmetry and elevated theta activity in voxels of the rACC, which may indicate less likelihood of depression and a higher likelihood of response to antidepressants. In conclusion, subtle EEG deviations, such as right-dominant central theta, alpha, and beta asymmetries and theta activity in the rACC may mark HIV-related depressive symptoms and may predict the likelihood of response to antidepressants but gender effects need to be taken into account. Although this study introduced the use of LORETA to examine the neurophysiological correlates of negative affect in PLWH, further research is needed to assess the utility of this tool in diagnostics and treatment monitoring of depression in PLWH. PMID:25568149

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

    NASA Technical Reports Server (NTRS)

    Clark, Jonathan B.; Riley, Terrence

    2001-01-01

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

  16. Epileptic EEG classification based on kernel sparse representation.

    PubMed

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

    2014-06-01

    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

  17. Standardized EEG interpretation accurately predicts prognosis after cardiac arrest

    PubMed Central

    Rossetti, Andrea O.; van Rootselaar, Anne-Fleur; Wesenberg Kjaer, Troels; Horn, Janneke; Ullén, Susann; Friberg, Hans; Nielsen, Niklas; Rosén, Ingmar; Åneman, Anders; Erlinge, David; Gasche, Yvan; Hassager, Christian; Hovdenes, Jan; Kjaergaard, Jesper; Kuiper, Michael; Pellis, Tommaso; Stammet, Pascal; Wanscher, Michael; Wetterslev, Jørn; Wise, Matt P.; Cronberg, Tobias

    2016-01-01

    Objective: To identify reliable predictors of outcome in comatose patients after cardiac arrest using a single routine EEG and standardized interpretation according to the terminology proposed by the American Clinical Neurophysiology Society. Methods: In this cohort study, 4 EEG specialists, blinded to outcome, evaluated prospectively recorded EEGs in the Target Temperature Management trial (TTM trial) that randomized patients to 33°C vs 36°C. Routine EEG was performed in patients still comatose after rewarming. EEGs were classified into highly malignant (suppression, suppression with periodic discharges, burst-suppression), malignant (periodic or rhythmic patterns, pathological or nonreactive background), and benign EEG (absence of malignant features). Poor outcome was defined as best Cerebral Performance Category score 3–5 until 180 days. Results: Eight TTM sites randomized 202 patients. EEGs were recorded in 103 patients at a median 77 hours after cardiac arrest; 37% had a highly malignant EEG and all had a poor outcome (specificity 100%, sensitivity 50%). Any malignant EEG feature had a low specificity to predict poor prognosis (48%) but if 2 malignant EEG features were present specificity increased to 96% (p < 0.001). Specificity and sensitivity were not significantly affected by targeted temperature or sedation. A benign EEG was found in 1% of the patients with a poor outcome. Conclusions: Highly malignant EEG after rewarming reliably predicted poor outcome in half of patients without false predictions. An isolated finding of a single malignant feature did not predict poor outcome whereas a benign EEG was highly predictive of a good outcome. PMID:26865516

  18. Interrater reliability of EEG-video monitoring

    PubMed Central

    Benbadis, S R.; LaFrance, W C.; Papandonatos, G D.; Korabathina, K; Lin, K; Kraemer, H C.

    2009-01-01

    Objective: The diagnosis of psychogenic nonepileptic seizures (PNES) can be challenging. In the absence of a gold standard to verify the reliability of the diagnosis by EEG-video, we sought to assess the interrater reliability of the diagnosis using EEG-video recordings. Methods: Patient samples consisted of 22 unselected consecutive patients who underwent EEG-video monitoring and had at least an episode recorded. Other test results and histories were not provided because the goal was to assess the reliability of the EEG-video. Data were sent to 22 reviewers, who were board-certified neurologists and practicing epileptologists at epilepsy centers. Choices were 1) PNES, 2) epilepsy, and 3) nonepileptic but not psychogenic (“physiologic”) events. Interrater agreement was measured using a κ coefficient for each diagnostic category. We used generalized κ coefficients, which measure the overall level of between-method agreement beyond that which can be ascribed to chance. We also report category-specific κ values. Results: For the diagnosis of PNES, there was moderate agreement (κ = 0.57, 95% confidence interval [CI] 0.39–0.76). For the diagnosis of epilepsy, there was substantial agreement (κ = 0.69, 95% CI 0.51–0.86). For physiologic nonepileptic episodes, the agreement was low (κ = 0.09, 95% CI 0.02–0.27). The overall κ statistic across all 3 diagnostic categories was moderate at 0.56 (95% CI 0.41–0.73). Conclusions: Interrater reliability for the diagnosis of psychogenic nonepileptic seizures by EEG-video monitoring was only moderate. Although this may be related to limitations of the study (diagnosis based on EEG-video alone, artificial nature of the forced choice paradigm, single episode), it highlights the difficulties and subjective components inherent to this diagnosis. GLOSSARY ABCN = American Board of Clinical Neurophysiology; ABPN = American Board of Psychiatry and Neurology; CI = confidence interval; IRR = interrater reliability; PNES = psychogenic nonepileptic seizures. PMID:19752450

  19. Abnormal Parietal Brain Function in ADHD: Replication and Extension of Previous EEG Beta Asymmetry Findings

    PubMed Central

    Hale, T. Sigi; Kane, Andrea M.; Tung, Kelly L.; Kaminsky, Olivia; McGough, James J.; Hanada, Grant; Loo, Sandra K.

    2014-01-01

    Background: Abundant work indicates ADHD abnormal posterior brain structure and function, including abnormal structural and functional asymmetries and reduced corpus callosum size. However, this literature has attracted considerably less research interest than fronto-striatal findings. Objective: To help address this imbalance, the current study replicates and extends our previous work showing abnormal parietal brain function in ADHD adults during the Conner’s Continuous Performance Test (CPT). Method: Our previous study found that ADHD adults had increased rightward EEG beta (16–21 Hz) asymmetry in inferior parietal brain regions during the CPT (p = 0.00001), and that this metric exhibited a lack of normal correlation (i.e., observed in controls) with beta asymmetry at temporal–parietal regions. We re-tested these effects in a new ADHD sample and with both new and old samples combined. We additionally examined: (a) EEG asymmetry in multiple frequency bands, (b) unilateral effects for all asymmetry findings, and (c) the association between EEG asymmetry and a battery of cognitive tests. Results: We replicated our original findings by demonstrating abnormal rightward inferior parietal beta asymmetry in adults with ADHD during the CPT, and again this metric exhibited abnormal reduced correlation to temporal–parietal beta asymmetry. Novel analyses also demonstrated a broader pattern of rightward beta and theta asymmetry across inferior, superior, and temporal–parietal brain regions, and showed that rightward parietal asymmetry in ADHD was atypically associated with multiple cognitive tests. Conclusion: Abnormal increased rightward parietal EEG beta asymmetry is an important feature of ADHD. We speculate that this phenotype may occur with any form of impaired capacity for top-down task-directed control over sensory encoding functions, and that it may reflect associated increase of attentional shifting and compensatory sustained/selective attention. PMID:25104941

  20. Heartbeat-related EEG amplitude and phase modulations from wakefulness to deep sleep: Interactions with sleep spindles and slow oscillations.

    PubMed

    Lechinger, Julia; Heib, Dominik Philip Johannes; Gruber, Walter; Schabus, Manuel; Klimesch, Wolfgang

    2015-11-01

    Based on physiological models of neurovisceral integration, different studies have shown how cognitive processes modulate heart rate and how the heartbeat, on the other hand, modulates brain activity. We tried to further determine interactions between cardiac and electrical brain activity by means of EEG. We investigated how the heartbeat modulates EEG in 23 healthy controls from wakefulness to deep sleep and showed that frontocentral heartbeat evoked EEG amplitude and phase locking (as measured by intertrial phase locking), at about 300-400 ms after the R peak, decreased with increasing sleep depth with a renewed increase during REM sleep, which underpins the assumption that the heartbeat evoked positivity constitutes an active frontocortical response to the heartbeat. Additionally, we found that individual heart rate was correlated with the frequency of the EEG's spectral peak (i.e., alpha peak frequency during wakefulness). This correlation was strongest during wakefulness and declined linearly with increasing sleep depth. Furthermore, we show that the QRS complex modulates spindle phase possibly related to the correspondence between the frequency of the QRS complex and the spindle frequency of about 12-15 Hz. Finally, during deep sleep stages, a loose temporal coupling between heartbeats and slow oscillation (0.8 Hz) could be observed. These findings indicate that cardiac activity such as heart rate or individual heartbeats can modulate or be modulated by ongoing oscillatory brain activity. PMID:26268858

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

    PubMed Central

    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

    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. PMID:20410729

  2. Joint source separation of simultaneous EEG-fMRI recording in two experimental conditions using common spatial patterns.

    PubMed

    Tan, Ao; Fu, Zening; Tu, Yiheng; Hung, Yeung Sam; Zhang, Zhiguo

    2015-08-01

    Simultaneous collection of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data has become increasingly popular in neuroscientific studies, because it can provide neural information with both high spatial and temporal resolution. In order to maximally utilize the information contained in simultaneous EEG-fMRI recording, many sophisticated multimodal data-mining methods, such as joint ICA, have been developed. However, these methods normally deal with data recorded in one experimental condition, and they cannot effectively extract information on activities that are distinct in two conditions. In this paper, a new data decomposition method called joint common spatial pattern (jCSP) is proposed. Compared with previous methods, the jCSP method exploits inter-conditional difference in the strength of brain source activities to achieve source separation, and is able to uncover the source activities with the strongest discriminative power. A group analysis based on clustering is further proposed to reveal distinctive jCSP patterns at group level. We applied joint CSP to a simultaneous EEG-fMRI dataset collected from 21 subjects under two different resting-state conditions (eyes-closed and eyes-open). Results show a distinct dynamic pattern shared by EEG alpha power and fMRI signal during eyes-open resting-state. PMID:26736832

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

    PubMed

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

    1996-07-01

    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

  4. Folate receptor {alpha} regulates cell proliferation in mouse gonadotroph {alpha}T3-1 cells

    SciTech Connect

    Yao, Congjun; Evans, Chheng-Orn; Stevens, Victoria L.; Owens, Timothy R.; Oyesiku, Nelson M.

    2009-11-01

    We have previously found that the mRNA and protein levels of the folate receptor alpha (FR{alpha}) are uniquely over-expressed in clinically human nonfunctional (NF) pituitary adenomas, but the mechanistic role of FR{alpha} has not fully been determined. We investigated the effect of FR{alpha} over-expression in the mouse gonadotroph {alpha}T3-1 cell line as a model for NF pituitary adenomas. We found that the expression and function of FR{alpha} were strongly up-regulated, by Western blotting and folic acid binding assay. Furthermore, we found a higher cell growth rate, an enhanced percentage of cells in S-phase by BrdU assay, and a higher PCNA staining. These observations indicate that over-expression of FR{alpha} promotes cell proliferation. These effects were abrogated in the same {alpha}T3-1 cells when transfected with a mutant FR{alpha} cDNA that confers a dominant-negative phenotype by inhibiting folic acid binding. Finally, by real-time quantitative PCR, we found that mRNA expression of NOTCH3 was up-regulated in FR{alpha} over-expressing cells. In summary, our data suggests that FR{alpha} regulates pituitary tumor cell proliferation and mechanistically may involve the NOTCH pathway. Potentially, this finding could be exploited to develop new, innovative molecular targeted treatment for human NF pituitary adenomas.

  5. Cross coherence independent component analysis in resting and action states EEG discrimination

    NASA Astrophysics Data System (ADS)

    Almurshedi, A.; Ismail, A. K.

    2014-11-01

    Cross Coherence time frequency transform and independent component analysis (ICA) method were used to analyse the electroencephalogram (EEG) signals in resting and action states during open and close eyes conditions. From the topographical scalp distributions of delta, theta, alpha, and beta power spectrum can clearly discriminate between the signal when the eyes were open or closed, but it was difficult to distinguish between resting and action states when the eyes were closed. In open eyes condition, the frontal area (Fp1, Fp2) was activated (higher power) in delta and theta bands whilst occipital (O1, O2) and partial (P3, P4, Pz) area of brain was activated alpha band in closed eyes condition. The cross coherence method of time frequency analysis is capable of discrimination between rest and action brain signals in closed eyes condition.

  6. Perceiving objects by their function: An EEG study on feature saliency and prehensile affordances.

    PubMed

    Kourtis, Dimitrios; Vingerhoets, Guy

    2015-09-01

    We examined the feature saliency and prehensile/motor affordance effects that are visually elicited by a graspable object's most salient features and graspable part, respectively. EEG was recorded from participants who attended a photo of an object, and responded to a left- or right-pointing arrow, which was overlaid on the object 1000 ms after object onset. Analysis of response times demonstrated the presence of a feature saliency effect. Lateralization of posterior alpha suppression showed that attention was initially directed to the object's (most salient) functional end. Pre-movement frontocentral beta suppression and the modulation of the P3 component showed that a response compatible to the functional end was activated before arrow onset. Moreover, lateralization of pre-movement posterior and central alpha suppression indicated a behaviorally masked affordance effect. This suggests that the two effects may occur independently, but without specific attention orienting instructions, the feature saliency effect dominates a potential prehensile affordance effect. PMID:26247331

  7. Tracking variations in the alpha activity in an electroencephalogram

    NASA Technical Reports Server (NTRS)

    Prabhu, K. S.

    1971-01-01

    The problem of tracking Alpha voltage variations in an electroencephalogram is discussed. This problem is important in encephalographic studies of sleep and effects of different stimuli on the brain. Very often the Alpha voltage is tracked by passing the EEG signal through a bandpass filter centered at the Alpha frequency, which hopefully will filter out unwanted noise from the Alpha activity. Some alternative digital techniques are suggested and their performance is compared with the standard technique. These digital techniques can be used in an environment where an electroencephalograph is interfaced with a small digital computer via an A/D convertor. They have the advantage that statistical statements about their variability can sometimes be made so that the effect sought can be assessed correctly in the presence of random fluctuations.

  8. Noisy Galvanic Vestibular Stimulation Modulates the Amplitude of EEG Synchrony Patterns

    PubMed Central

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

    2013-01-01

    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. PMID:23874865

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

    PubMed Central

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

    2014-01-01

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

  10. Study on Bayes Discriminant Analysis of EEG Data

    PubMed Central

    Shi, Yuan; He, DanDan; Qin, Fang

    2014-01-01

    Objective: In this paper, we have done Bayes Discriminant analysis to EEG data of experiment objects which are recorded impersonally come up with a relatively accurate method used in feature extraction and classification decisions. Methods: In accordance with the strength of α wave, the head electrodes are divided into four species. In use of part of 21 electrodes EEG data of 63 people, we have done Bayes Discriminant analysis to EEG data of six objects. Results In use of part of EEG data of 63 people, we have done Bayes Discriminant analysis, the electrode classification accuracy rates is 64.4%. Conclusions: Bayes Discriminant has higher prediction accuracy, EEG features (mainly αwave) extract more accurate. Bayes Discriminant would be better applied to the feature extraction and classification decisions of EEG data. PMID:25852784

  11. EEG frequency analysis of cortical brain activities induced by effect of light touch.

    PubMed

    Ishigaki, Tomoya; Ueta, Kozo; Imai, Ryota; Morioka, Shu

    2016-06-01

    In human postural control, touching a fingertip to a stable object with a slight force (<1 N) reduces postural sway independent of mechanical support, which is referred to as the effect of light touch (LT effect). The LT effect is achieved by the spatial orientation according to haptic feedback acquired from an external spatial reference. However, the neural mechanism of the LT effect is incompletely understood. Therefore, the purpose of this study was to employ EEG frequency analysis to investigate the cortical brain activity associated with the LT effect when attentional focus was strictly controlled with the eyes closed during standing (i.e., control, fixed-point touch, sway-referenced touch, and only fingertip attention). We used EEG to measure low-alpha (about 8-10 Hz) and high-alpha rhythm (about 10-12 Hz) task-related power decrease/increase (TRPD/TRPI). The LT effect was apparent only when the subject acquired the stable external spatial reference (i.e., fixed-point touch). Furthermore, the LT-specific effect increased the high-alpha TRPD of two electrodes (C3, P3), which were mainly projected from cortical brain activities of the left primary sensorimotor cortex area and left posterior parietal cortex area. Furthermore, there was a negative correlation between the LT effect and increased TRPD of C3. In contrast, the LT effect correlated positively with increased TRPD of P3. These results suggest that central and parietal high-alpha TRPD of the contralateral hemisphere reflects the sensorimotor information processing and sensory integration for the LT effect. These novel findings reveal a partial contribution of a cortical neural mechanism for the LT effect. PMID:26758719

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

    PubMed

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

    2014-08-15

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

  13. Independent component analysis of EEG dipole source localization in resting and action state of brain

    NASA Astrophysics Data System (ADS)

    Almurshedi, Ahmed; Ismail, Abd Khamim

    2015-04-01

    EEG source localization was studied in order to determine the location of the brain sources that are responsible for the measured potentials at the scalp electrodes using EEGLAB with Independent Component Analysis (ICA) algorithm. Neuron source locations are responsible in generating current dipoles in different states of brain through the measured potentials. The current dipole sources localization are measured by fitting an equivalent current dipole model using a non-linear optimization technique with the implementation of standardized boundary element head model. To fit dipole models to ICA components in an EEGLAB dataset, ICA decomposition is performed and appropriate components to be fitted are selected. The topographical scalp distributions of delta, theta, alpha, and beta power spectrum and cross coherence of EEG signals are observed. In close eyes condition it shows that during resting and action states of brain, alpha band was activated from occipital (O1, O2) and partial (P3, P4) area. Therefore, parieto-occipital area of brain are active in both resting and action state of brain. However cross coherence tells that there is more coherence between right and left hemisphere in action state of brain than that in the resting state. The preliminary result indicates that these potentials arise from the same generators in the brain.

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

    PubMed Central

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

    2014-01-01

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

  15. Using Single-trial EEG to Predict and Analyze Subsequent Memory

    PubMed Central

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

    2013-01-01

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

  16. Decreased Modulation of EEG Oscillations in High-Functioning Autism during a Motor Control Task

    PubMed Central

    Ewen, Joshua B.; Lakshmanan, Balaji M.; Pillai, Ajay S.; McAuliffe, Danielle; Nettles, Carrie; Hallett, Mark; Crone, Nathan E.; Mostofsky, Stewart H.

    2016-01-01

    Autism spectrum disorders (ASD) are thought to result in part from altered cortical excitatory-inhibitory balance; this pathophysiology may impact the generation of oscillations on electroencephalogram (EEG). We investigated premotor-parietal cortical physiology associated with praxis, which has strong theoretical and empirical associations with ASD symptomatology. Twenty five children with high-functioning ASD (HFA) and 33 controls performed a praxis task involving the pantomiming of tool use, while EEG was recorded. We assessed task-related modulation of signal power in alpha and beta frequency bands. Compared with controls, subjects with HFA showed 27% less left central (motor/premotor) beta (18–22 Hz) event-related desynchronization (ERD; p = 0.030), as well as 24% less left parietal alpha (7–13 Hz) ERD (p = 0.046). Within the HFA group, blunting of central ERD attenuation was associated with impairments in clinical measures of praxis imitation (r = −0.4; p = 0.04) and increased autism severity (r = 0.48; p = 0.016). The modulation of central beta activity is associated, among other things, with motor imagery, which may be necessary for imitation. Impaired imitation has been associated with core features of ASD. Altered modulation of oscillatory activity may be mechanistically involved in those aspects of motor network function that relate to the core symptoms of ASD. PMID:27199719

  17. Preliminary study of Alzheimer's Disease diagnosis based on brain electrical signals using wireless EEG

    NASA Astrophysics Data System (ADS)

    Handayani, N.; Akbar, Y.; Khotimah, S. N.; Haryanto, F.; Arif, I.; Taruno, W. P.

    2016-03-01

    This research aims to study brain's electrical signals recorded using EEG as a basis for the diagnosis of patients with Alzheimer's Disease (AD). The subjects consisted of patients with AD, and normal subjects are used as the control. Brain signals are recorded for 3 minutes in a relaxed condition and with eyes closed. The data is processed using power spectral analysis, brain mapping and chaos test to observe the level of complexity of EEG's data. The results show a shift in the power spectral in the low frequency band (delta and theta) in AD patients. The increase of delta and theta occurs in lobus frontal area and lobus parietal respectively. However, there is a decrease of alpha activity in AD patients where in the case of normal subjects with relaxed condition, brain alpha wave dominates the posterior area. This is confirmed by the results of brain mapping. While the results of chaos analysis show that the average value of MMLE is lower in AD patients than in normal subjects. The level of chaos associated with neural complexity in AD patients with lower neural complexity is due to neuronal damage caused by the beta amyloid plaques and tau protein in neurons.

  18. A Discriminative Approach to EEG Seizure Detection

    PubMed Central

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

    2011-01-01

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

  19. Interhemispheric differences in awake and sleep human EEG: a comparison between non-linear and spectral measures.

    PubMed

    Pereda, E; Gamundi, A; Nicolau, M C; Rial, R; González, J

    1999-03-19

    Interhemispheric differences in the EEG of nine healthy right-handed human subjects (C3 vs. C4 derivations) were investigated during resting wake with closed eyes (CE) and sleep stages I, II, III, IV and REM. The harmonic power spectral density within the EEG main spectral bands, the fractal (Dr) and the correlation (D2) dimension as well as the largest Lyapunov exponent (lambda1) of both hemispheres were compared. In addition, the relationships between non-linear and spectral measures were analyzed. Dr, D2, lambda1 and the power in alpha band exhibited interhemispheric differences during waking, the values from the right hemisphere (RH) being higher than those of the left (LH) except for lambda1. During slow wave sleep (SWS), non-linear parameters detected opposite EEG asymmetries (D2 in stage III and lambda1 in stage IV) to those found in the other behavioural stages. In addition, both D2 and lambda1 were correlated (negatively) with the power in the delta band, but lambda1 was also correlated (positively) with the power in the alpha and beta bands. In conclusion, RH appears to be more complex though more predictable than the LH during CE and sleep stages I and II, these characteristics changing to the LH during SWS. PMID:10218905

  20. Exploring EEG signals in a Brain-Computer Interface

    NASA Astrophysics Data System (ADS)

    Zubrycki, Paweł; Mulawka, Jan

    2014-11-01

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

  1. Atypical sleep architecture and the autism phenotype.

    PubMed

    Limoges, Elyse; Mottron, Laurent; Bolduc, Christianne; Berthiaume, Claude; Godbout, Roger

    2005-05-01

    A growing body of evidence indicates that people with autism frequently experience sleep disorders and exhibit atypical sleep architecture. In order to establish whether sleep disorders truly belong to the autism spectrum disorder (ASD) phenotype, we conducted a subjective and objective study of sleep in a group of high-functioning adults with ASD but without sleep complaints, psychiatric disorders or neurological comorbidity. We compared the subjective data of 27 ASD participants with those of 78 healthy controls matched for chronological age and gender. Subjective measures of sleep in the clinical group were compatible with insomnia and/or a tolerable phase advance of the sleep-wake cycle. Subjective data were confirmed by objective laboratory sleep recordings in a subset of 16 patients and 16 controls. Persons with autism presented with a longer sleep latency (P < 0.04), more frequent nocturnal awakenings (P < 0.03), lower sleep efficiency (P < 0.03), increased duration of stage 1 sleep (P < 0.02), decreased non-REM sleep (stages 2 + 3 + 4, P < 0.04) and slow-wave sleep (stages 3 + 4, P < 0.05), fewer stage 2 EEG sleep spindles (P < 0.004), and a lower number of rapid eye movements during REM sleep (P < 0.006) than did control participants. On clinical scales, the scores of persons with ASD on the Beck Depression Inventory were similar to those of persons without, but their trait anxiety scores on the Spielberger Anxiety Scale were higher (P < 0.02). The state anxiety scores of the Spielberger scale and cortisol levels were the same in the two groups. Objective total sleep time correlated negatively with the Social (-0.52, P < 0.05) and Communication (-0.54, P < 0.02) scales of the Autism Diagnostic Interview-Revised. The sleep of clinical subgroups (10 with high-functioning autism, six with Asperger syndrome) did not differ, except for the presence of fewer EEG sleep spindles in the Asperger syndrome subgroup (P < 0.05). In conclusion, these findings indicate that atypicalities of sleep constitute a salient feature of the adult ASD phenotype and this should be further investigated in younger patients. Moreover, the results are consistent with an atypical organization of neural networks subserving the macro- and microstructure of sleep in ASD. We are furthering this research with quantified analysis of sleep EEG. PMID:15705609

  2. Left temporal alpha-band activity reflects single word intelligibility

    PubMed Central

    Becker, Robert; Pefkou, Maria; Michel, Christoph M.; Hervais-Adelman, Alexis G.

    2013-01-01

    The electroencephalographic (EEG) correlates of degraded speech perception have been explored in a number of recent studies. However, such investigations have often been inconclusive as to whether observed differences in brain responses between conditions result from different acoustic properties of more or less intelligible stimuli or whether they relate to cognitive processes implicated in comprehending challenging stimuli. In this study we used noise vocoding to spectrally degrade monosyllabic words in order to manipulate their intelligibility. We used spectral rotation to generate incomprehensible control conditions matched in terms of spectral detail. We recorded EEG from 14 volunteers who listened to a series of noise vocoded (NV) and noise-vocoded spectrally-rotated (rNV) words, while they carried out a detection task. We specifically sought components of the EEG response that showed an interaction between spectral rotation and spectral degradation. This reflects those aspects of the brain electrical response that are related to the intelligibility of acoustically degraded monosyllabic words, while controlling for spectral detail. An interaction between spectral complexity and rotation was apparent in both evoked and induced activity. Analyses of event-related potentials showed an interaction effect for a P300-like component at several centro-parietal electrodes. Time-frequency analysis of the EEG signal in the alpha-band revealed a monotonic increase in event-related desynchronization (ERD) for the NV but not the rNV stimuli in the alpha band at a left temporo-central electrode cluster from 420–560 ms reflecting a direct relationship between the strength of alpha-band ERD and intelligibility. By matching NV words with their incomprehensible rNV homologues, we reveal the spatiotemporal pattern of evoked and induced processes involved in degraded speech perception, largely uncontaminated by purely acoustic effects. PMID:24416001

  3. Synchronization of EEG activity in patients with bipolar disorder

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  4. [Central EEG rhythm associated with movement and EEG rhythm associated with spatial reasoning: are they homologous?].

    PubMed

    Tarotin, I V; Ivanitsky, G A

    2014-01-01

    EEG rhythmical picture of subject's movement suppression and spatial-figurative task solving was examined and analyzed. Rhythms appearing during spatial reasoning and suppressed movements with the frequency of about 11 Hz were isolated. It was hypothesized that a functional link exists between these rhythms in the considered behavioral tests. To test the hypothesis and to reveal this connection, experiments were developed and carried out. Then the analysis of recorded EEG signals was conducted by applying Fourier transform, independent component analysis (ICA) and equivalent dipole source localization. Unexpected conclusion about the existence of a general mechanism of movement suppression was drawn. PMID:25975138

  5. The qEEG Signature of Selective NMDA NR2B Negative Allosteric Modulators; A Potential Translational Biomarker for Drug Development

    PubMed Central

    Keavy, Deborah; Bristow, Linda J.; Sivarao, Digavalli V.; Batchelder, Margaret; King, Dalton; Thangathirupathy, Srinivasan; Macor, John E.; Weed, Michael R.

    2016-01-01

    The antidepressant activity of the N-methyl-D-aspartate (NMDA) receptor channel blocker, ketamine, has led to the investigation of negative allosteric modulators (NAMs) selective for the NR2B receptor subtype. The clinical development of NR2B NAMs would benefit from a translational pharmacodynamic biomarker that demonstrates brain penetration and functional inhibition of NR2B receptors in preclinical species and humans. Quantitative electroencephalography (qEEG) is a translational measure that can be used to demonstrate pharmacodynamic effects across species. NMDA receptor channel blockers, such as ketamine and phencyclidine, increase the EEG gamma power band, which has been used as a pharmacodynamic biomarker in the development of NMDA receptor antagonists. However, detailed qEEG studies with ketamine or NR2B NAMs are lacking in nonhuman primates. The aim of the present study was to determine the effects on the qEEG power spectra of the NR2B NAMs traxoprodil (CP-101,606) and BMT-108908 in nonhuman primates, and to compare them to the NMDA receptor channel blockers, ketamine and lanicemine. Cynomolgus monkeys were surgically implanted with EEG radio-telemetry transmitters, and qEEG was measured after vehicle or drug administration. The relative power for a number of frequency bands was determined. Ketamine and lanicemine increased relative gamma power, whereas the NR2B NAMs traxoprodil and BMT-108908 had no effect. Robust decreases in beta power were elicited by ketamine, traxoprodil and BMT-108908; and these agents also produced decreases in alpha power and increases in delta power at the doses tested. These results suggest that measurement of power spectra in the beta and delta bands may represent a translational pharmacodynamic biomarker to demonstrate functional effects of NR2B NAMs. The results of these studies may help guide the selection of qEEG measures that can be incorporated into early clinical evaluation of NR2B NAMs in healthy humans. PMID:27035340

  6. The qEEG Signature of Selective NMDA NR2B Negative Allosteric Modulators; A Potential Translational Biomarker for Drug Development.

    PubMed

    Keavy, Deborah; Bristow, Linda J; Sivarao, Digavalli V; Batchelder, Margaret; King, Dalton; Thangathirupathy, Srinivasan; Macor, John E; Weed, Michael R

    2016-01-01

    The antidepressant activity of the N-methyl-D-aspartate (NMDA) receptor channel blocker, ketamine, has led to the investigation of negative allosteric modulators (NAMs) selective for the NR2B receptor subtype. The clinical development of NR2B NAMs would benefit from a translational pharmacodynamic biomarker that demonstrates brain penetration and functional inhibition of NR2B receptors in preclinical species and humans. Quantitative electroencephalography (qEEG) is a translational measure that can be used to demonstrate pharmacodynamic effects across species. NMDA receptor channel blockers, such as ketamine and phencyclidine, increase the EEG gamma power band, which has been used as a pharmacodynamic biomarker in the development of NMDA receptor antagonists. However, detailed qEEG studies with ketamine or NR2B NAMs are lacking in nonhuman primates. The aim of the present study was to determine the effects on the qEEG power spectra of the NR2B NAMs traxoprodil (CP-101,606) and BMT-108908 in nonhuman primates, and to compare them to the NMDA receptor channel blockers, ketamine and lanicemine. Cynomolgus monkeys were surgically implanted with EEG radio-telemetry transmitters, and qEEG was measured after vehicle or drug administration. The relative power for a number of frequency bands was determined. Ketamine and lanicemine increased relative gamma power, whereas the NR2B NAMs traxoprodil and BMT-108908 had no effect. Robust decreases in beta power were elicited by ketamine, traxoprodil and BMT-108908; and these agents also produced decreases in alpha power and increases in delta power at the doses tested. These results suggest that measurement of power spectra in the beta and delta bands may represent a translational pharmacodynamic biomarker to demonstrate functional effects of NR2B NAMs. The results of these studies may help guide the selection of qEEG measures that can be incorporated into early clinical evaluation of NR2B NAMs in healthy humans. PMID:27035340

  7. Amplitude-Integrated EEG and Range-EEG Modulation Associated with Pneumatic Orocutaneous Stimulation in Preterm Infants

    PubMed Central

    Barlow, Steven M; Jegatheesan, Priya; Weiss, Sunshine; Govindaswami, Balaji; Wang, Jingyan; Lee, Jaehoon; Oder, Austin; Song, Dongli

    2013-01-01

    Background Controlled somatosensory stimulation strategies have demonstrated merit in developing oral feeding skills in premature infants who lack a functional suck, however, the effects of orosensory entrainment stimulation on electrocortical dynamics is unknown. Objective To determine the effects of servo-controlled pneumatic orocutaneous stimulation presented during gavage feedings on the modulation of aEEG and rEEG activity. Methods Two-channel EEG recordings were collected during 180 sessions that included orocutaneous stimulation and non-stimulation epochs among 22 preterm infants (mean gestational age = 28.56 weeks) who were randomized to treatment and control ‘sham’ conditions. The study was initiated at around 32 weeks post-menstrual age (PMA). The raw EEG was transformed into amplitude-integrated EEG (aEEG) margins, and range-EEG (rEEG) amplitude bands measured at 1-minute intervals and subjected to a mixed models statistical analysis. Results Multiple significant effects were observed in the processed EEG during and immediately following 3-minute periods of orocutaneous stimulation, including modulation of the upper and lower margins of the aEEG, and a reorganization of rEEG with an apparent shift from amplitude bands D and E to band C throughout the 23-minute recording period that followed the first stimulus block when compared to the sham condition. Cortical asymmetry also was apparent in both EEG measures. Conclusions Orocutaneous stimulation represents a salient trigeminal input which has both short- and long-term effects in modulating electrocortical activity, and thus, is hypothesized to represent a form of neural adaptation or plasticity that may benefit the preterm infant during this critical period of brain maturation. PMID:24310443

  8. Effects of acute nicotine administration on behavioral and neural (EEG) correlates of working memory in non-smokers.

    PubMed

    Fisher, Derek J; Daniels, Richelle; Jaworska, Natalia; Knobelsdorf, Amy; Knott, Verner J

    2012-01-01

    Enhancements in working memory (WM) performance have been previously reported following acute smoking/nicotine. Neuroimaging and behavioral assessments of nicotine's effects on WM have yielded inconsistent findings. Few studies, however, have examined the effects of nicotine on WM-related neural activity in non-smokers. The present study examined the effect of acute nicotine gum administration (6 mg) on electroencephalographic (EEG) activity (alpha(1), alpha(2) and theta bands) and performance on the parametrically manipulated N-back task of WM in 20 non-smoking adults. EEG activity varied with WM load (e.g. alpha(1) decreasing and theta increasing). Performance on the N-back was also load-sensitive, with slower reaction times and decreased accuracy associated with increasing memory load. Neither response speed nor accuracy measures were affected by nicotine but EEG was, with the effects varying by load and brain region. Nicotine-induced increases in alpha(2) and theta were observed under lower (0-, 1-back) memory load conditions Additionally, nicotine significantly reduced signal detection sensitivity values and altered response bias toward being more conservative at all levels of the N-back. Taken together, these findings suggest that while nicotine may boost WM neural processes at lower levels of WM load in non-smokers, it also may activate concurrent behavioral inhibition networks that negate any effects on behavioral performance. Additionally, nicotine appears to have no impact, or perhaps a negative impact, on these processes under more demanding (2-back, 3-back) conditions in non-smokers. PMID:22079316

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

    PubMed Central

    2014-01-01

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

  10. An introduction to statistical concepts for the analysis of EEG data and the planning of pharmaco-EEG trials.

    PubMed

    Schlattmann, P

    2002-01-01

    The use of descriptive statistics and graphics for electroencephalogram (EEG) data after initial data reduction and the application of hypothesis tests to EEG data are described. In planning pharmaco-EEG trials, some notion of statistical power and variability of effect size is necessary as they are used to calculate sample size in parallel-group clinical trials. The need for sensitivity analysis during the study planning phase is demonstrated as well. Because EEG data are highly dimensional data, an outline of methods for reducing dimensionality is provided. These concepts are demonstrated using data from patients with Alzheimer's disease and from healthy controls. PMID:12575482

  11. Lateralized modulation of posterior alpha oscillations in children.

    PubMed

    Vollebregt, Madelon A; Zumer, Johanna M; Ter Huurne, Niels; Castricum, Jesminne; Buitelaar, Jan K; Jensen, Ole

    2015-12-01

    The evidence for a functionally inhibitory role of alpha oscillations is growing stronger, mostly derived from studies in healthy adults investigating spatial attention. It remains unexplored if the modulation of alpha band oscillations plays a similar functional role in typically developing children. The aim of this study was to characterize alpha modulations in children in relation to attentional performance. To this end, the posterior alpha activity (8-12Hz) in children between 7 and 10years old was measured using EEG while they performed a visuospatial covert attention task. We found that the alpha activity decreased in the hemisphere contralateral to the attended hemifield, whereas it relatively increased in the other hemisphere. In addition, we found that the degree of lateralized alpha modulation predicted performance on the attention task by negatively predicting the response time on invalid trials. Of note, children who were behaviorally less influenced by spatial cueing also were children with a clear lateralized alpha modulation pattern, with a significantly stronger alpha lateralization in the left hemisphere than children who were influenced more by spatial cueing. In addition, a bias to the right visual field such as that commonly observed in children, was significantly smaller or absent in the children influenced least by spatial cueing. Among all children, the magnitude of this visual field bias was positively related to the ability to modulate alpha activity. In conclusion, we have shown that the pattern of alpha oscillations modulated by attention is already present in 7-10year old typically developing children. Although a similar pattern is observed in adults, the consequences for behavior are different. The fact that alpha modulation is already present at this age opens up the possibility of using hemispheric alpha lateralization as a tool to study the physiological basis of attention deficits in clinical disorders such as ADHD. PMID:26119021

  12. Standardized Computer-based Organized Reporting of EEG: SCORE

    PubMed Central

    Beniczky, Sndor; Aurlien, Harald; Brgger, Jan C; Fuglsang-Frederiksen, Anders; Martins-da-Silva, Antnio; Trinka, Eugen; Visser, Gerhard; Rubboli, Guido; Hjalgrim, Helle; Stefan, Hermann; Rosn, Ingmar; Zarubova, Jana; Dobesberger, Judith; Alving, Jrgen; Andersen, Kjeld V; Fabricius, Martin; Atkins, Mary D; Neufeld, Miri; Plouin, Perrine; Marusic, Petr; Pressler, Ronit; Mameniskiene, Ruta; Hopfengrtner, Rdiger; Emde Boas, Walter; Wolf, Peter

    2013-01-01

    The electroencephalography (EEG) signal has a high complexity, and the process of extracting clinically relevant features is achieved by visual analysis of the recordings. The interobserver agreement in EEG interpretation is only moderate. This is partly due to the method of reporting the findings in free-text format. The purpose of our endeavor was to create a computer-based system for EEG assessment and reporting, where the physicians would construct the reports by choosing from predefined elements for each relevant EEG feature, as well as the clinical phenomena (for video-EEG recordings). A working group of EEG experts took part in consensus workshops in Dianalund, Denmark, in 2010 and 2011. The faculty was approved by the Commission on European Affairs of the International League Against Epilepsy (ILAE). The working group produced a consensus proposal that went through a pan-European review process, organized by the European Chapter of the International Federation of Clinical Neurophysiology. The Standardised Computer-based Organised Reporting of EEG (SCORE) software was constructed based on the terms and features of the consensus statement and it was tested in the clinical practice. The main elements of SCORE are the following: personal data of the patient, referral data, recording conditions, modulators, background activity, drowsiness and sleep, interictal findings, episodes (clinical or subclinical events), physiologic patterns, patterns of uncertain significance, artifacts, polygraphic channels, and diagnostic significance. The following specific aspects of the neonatal EEGs are scored: alertness, temporal organization, and spatial organization. For each EEG finding, relevant features are scored using predefined terms. Definitions are provided for all EEG terms and features. SCORE can potentially improve the quality of EEG assessment and reporting; it will help incorporate the results of computer-assisted analysis into the report, it will make possible the build-up of a multinational database, and it will help in training young neurophysiologists. PMID:23506075

  13. Event-related EEG oscillations to semantically unrelated words in normal and learning disabled children.

    PubMed

    Fernández, Thalía; Harmony, Thalía; Mendoza, Omar; López-Alanís, Paula; Marroquín, José Luis; Otero, Gloria; Ricardo-Garcell, Josefina

    2012-10-01

    Learning disabilities (LD) are one of the most frequent problems for elementary school-aged children. In this paper, event-related EEG oscillations to semantically related and unrelated pairs of words were studied in a group of 18 children with LD not otherwise specified (LD-NOS) and in 16 children with normal academic achievement. We propose that EEG oscillations may be different in LD NOS children versus normal control children that may explain some of the deficits observed in the LD-NOS group. The EEGs were recorded using the 10/20 system. EEG segments were edited by visual inspection 1000ms before and after the stimulus, and only correct responses were considered in the analysis. Time-frequency (1-50Hz) topographic maps were obtained for the increases and decreases of power after the event with respect to the pre-stimulus average values. Significant differences between groups were observed in the behavioral responses. LD-NOS children show less number of correct responses and more omissions and false alarms than the control group. The event-induced EEG responses showed significant differences between groups. The control group showed greater power increases in the frequencies 1-6Hz than the LD-NOS group from 300 to 700ms. These differences were mainly observed in frontal regions, both to related and non-related words. This was interpreted as a deficit in attention, both to internal and external events, deficits in activation of working memory and deficits in encoding and memory retrieval in the LD-NOS children. Differences between groups were also observed in the suppression of alpha and beta rhythms in the occipital regions to related words in frequencies between 8 and 17Hz from 450 to 750ms. LD-NOS children showed shorter durations of the decreases in power than the control group. These results suggest also deficits in attention and memory retrieval. It may be concluded that LD-NOS children showed physiological differences from normal children that may explain their cognitive deficiencies. PMID:22634034

  14. Enhanced right hemisphere activation in the mathematically precocious: a preliminary EEG investigation.

    PubMed

    O'Boyle, M W; Alexander, J E; Benbow, C P

    1991-11-01

    A preliminary electroencephalographic (EEG) investigation was conducted to determine if the pattern of hemispheric activation in mathematically precocious youth differs from that of average math ability subjects. Alpha activity at four brain sites (frontal, temporal, parietal, and occipital lobes) over the left and right cerebral hemispheres (LH/RH) was monitored while 12- to 14-year-old, right-handed males: (a) looked at a blank slide (baseline condition), (b) judged which of two chimeric faces was "happier," and (c) determined if a word was a noun or a verb. At baseline, the LH of the precocious group was found to be more active at all four brain sites relative to that of the average ability group. During chimeric face processing, the gifted subjects exhibited a significant reduction in alpha power over the RH, primarily at the temporal lobe, while no such alpha suppression was observed in the average ability subjects. For noun/verb determinations, no significant alpha power reductions were obtained for either group. These electrophysiological data generally corroborate the behavioral findings of O'Boyle and Benbow (1990a) and support their contention that enhanced RH involvement during cognitive processing may be a correlate of mathematical precocity. Moreover, the pattern of activation observed across tasks suggests that the ability to effectively coordinate LH and RH processing resources at an early age may be linked to intellectual giftedness. PMID:1799450

  15. The effects of catechol-O-methyl-transferase polymorphism Val158Met on functional connectivity in healthy young females: a resting EEG study.

    PubMed

    Lee, Tien-Wen; Yu, Younger W-Y; Hong, Chen-Jee; Tsai, Shih-Jen; Wu, Hung-Chi; Chen, Tai-Jui

    2011-03-01

    The catechol-O-methyl-transferase (COMT) gene has been linked to a wide spectrum of human phenotypes, including cognition, affective response, pain sensitivity, anxiety and psychosis. This study examined the modulatory effects of COMT Val158Met on neural interactions, indicated by connectivity strengths. Blood samples and resting state eyes-closed EEG signals were collected in 254 healthy young females. The COMT Val158Met polymorphism was decoded into 3 groups: Val/Val, Val/Met and Met/Met. The values of mutual information of 20 frontal-related channel pairs across delta, theta, alpha and beta frequencies were analyzed based on the time-frequency mutual information method. Our one-way ANOVA analyses revealed that the significant connection-frequency pairs were relatively left lateralized (P<0.01) and included F7-T3 and F7-C3 at delta frequency, and F3-F4, F7-T3, F7-C3, F7-P3, F3-C3, F3-F7 and F4-F8 at theta frequency. The F-test at F7-T3 and F7-C3 theta surpassed the statistical threshold of P<0.003 (after Bonferroni correction). For all the above connection-frequency pairs, there was a dose-dependent trend in the connectivity strengths of the alleles as follows: Val/Val>Val/Met>Met/Met. Our analyses complemented previous literature regarding neural modulation by the COMT Val158Met polymorphism. The implication to the pathogenesis in schizophrenia was also discussed. Further studies are needed to clarify whether there is gender difference on this gene-brain interaction. PMID:21195697

  16. Multi-channel EEG signal feature extraction and pattern recognition on horizontal mental imagination task of 1-D cursor movement for brain computer interface.

    PubMed

    Serdar Bascil, M; Tesneli, Ahmet Y; Temurtas, Feyzullah

    2015-06-01

    Brain computer interfaces (BCIs), based on multi-channel electroencephalogram (EEG) signal processing convert brain signal activities to machine control commands. It provides new communication way with a computer by extracting electroencephalographic activity. This paper, deals with feature extraction and classification of horizontal mental task pattern on 1-D cursor movement from EEG signals. The hemispherical power changes are computed and compared on alpha & beta frequencies and horizontal cursor control extracted with only mental imagination of cursor movements. In the first stage, features are extracted with the well-known average signal power or power difference (alpha and beta) method. Principal component analysis is used for reducing feature dimensions. All features are classified and the mental task patterns are recognized by three neural network classifiers which learning vector quantization, multilayer neural network and probabilistic neural network due to obtaining acceptable good results and using successfully in pattern recognition via k-fold cross validation technique. PMID:25982878

  17. The results of computer-assisted ambulatory 16-channel EEG.

    PubMed

    Morris, G L; Galezowska, J; Leroy, R; North, R

    1994-09-01

    The objective of this study was to examine the results of 16-channel computer-assisted outpatient long-term EEG monitoring (CO-LTM) and to compare those results to previously published reports using 4- and 8-channel ambulatory cassette-based continuous recordings. Patients were referred to a community-based outpatient EEG service for further diagnostic evaluation using this 16-channel bipolar recording system. 344 patients were recorded for an average of 1.4 days. EEG was reviewed for the presence of patient identified events, computer identified interictal and ictal abnormalities, and periodic time samples. A push-button recording that signified a clinical event was obtained in 166 patients (48.3%); 41 (11.9%) of these recordings included a seizure and 125 (36.3%) showed no EEG changes during the habitual event. An EEG abnormality was identified by the computer in an additional 90 recordings (26.2%), for an overall clinical usefulness of 74.4%. Among the 191 patients referred with previously normal routine EEGs, a total of 129 (67.5%) of these recordings were useful. 48 (25.1%) of these tracings were abnormal and an additional 81 push-button events (42.4%) showing no changes from background EEG were recorded. In conclusion, computer-assisted outpatient EEG monitoring provides good success rates for clinically useful information. PMID:7522152

  18. Intuitionistic fuzzy approach in enhancing image of flat EEG

    NASA Astrophysics Data System (ADS)

    Zenian, Suzelawati; Ahmad, Tahir; Idris, Amidora

    2014-07-01

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

  19. Effects of Fipronil on the EEG of Long Evans Rats

    EPA Science Inventory

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

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

    ERIC Educational Resources Information Center

    Sterman, M. Barry

    2000-01-01

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

  1. Single-trial EEG analysis using similarity measure.

    PubMed

    Hsu, Wei-Yen

    2015-12-17

    Single-trial electroencephalogram (EEG) data are analyzed with similarity measure. Time-frequency representation is constructed from EEG signals. It is then weighted with t-statistics. Finally, the test data are discriminated with similarity measure. Compared with non-weighted version, the experimental results indicate that the proposed method obtains better results in classification accuracy. PMID:26684888

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

    ERIC Educational Resources Information Center

    Sterman, M. Barry

    2000-01-01

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

  3. Using EEG to Study Cognitive Development: Issues and Practices

    ERIC Educational Resources Information Center

    Bell, Martha Ann; Cuevas, Kimberly

    2012-01-01

    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…

  4. EEG Patterns Related to Cognitive Tasks of Varying Complexity.

    ERIC Educational Resources Information Center

    Dunn, Denise A.; And Others

    A study was conducted that attempted to show changes in electroencephalographic (EEG) patterns (identified using topographic EEG mapping) when children were required to perform the relatively simple task of button pressing during an eyes-open baseline session of low cognitive demand and a complex reaction time (RT) task of high cognitive demand.

  5. Pulse artifact detection in simultaneous EEG-fMRI recording based on EEG map topography.

    PubMed

    Iannotti, Giannina R; Pittau, Francesca; Michel, Christoph M; Vulliemoz, Serge; Grouiller, Frédéric

    2015-01-01

    One of the major artifact corrupting electroencephalogram (EEG) acquired during functional magnetic resonance imaging (fMRI) is the pulse artifact (PA). It is mainly due to the motion of the head and attached electrodes and wires in the magnetic field occurring after each heartbeat. In this study we propose a novel method to improve PA detection by considering the strong gradient and inversed polarity between left and right EEG electrodes. We acquired high-density EEG-fMRI (256 electrodes) with simultaneous electrocardiogram (ECG) at 3 T. PA was estimated as the voltage difference between right and left signals from the electrodes showing the strongest artifact (facial and temporal). Peaks were detected on this estimated signal and compared to the peaks in the ECG recording. We analyzed data from eleven healthy subjects, two epileptic patients and four healthy subjects with an insulating layer between electrodes and scalp. The accuracy of the two methods was assessed with three criteria: (i) standard deviation, (ii) kurtosis and (iii) confinement into the physiological range of the inter-peak intervals. We also checked whether the new method has an influence on the identification of epileptic spikes. Results show that estimated PA improved artifact detection in 15/17 cases, when compared to the ECG method. Moreover, epileptic spike identification was not altered by the correction. The proposed method improves the detection of pulse-related artifacts, particularly crucial when the ECG is of poor quality or cannot be recorded. It will contribute to enhance the quality of the EEG increasing the reliability of EEG-informed fMRI analysis. PMID:25307731

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

    PubMed

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

    2013-04-01

    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 μ 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

  7. EEG Oscillation Evidences of Enhanced Susceptibility to Emotional Stimuli during Adolescence

    PubMed Central

    Meng, Xianxin; Liu, Wenwen; Zhang, Ling; Li, Xiang; Yao, Bo; Ding, Xinsheng; Yuan, JiaJin; Yang, Jiemin

    2016-01-01

    Background: Our recent event-related potential (ERP) study showed that adolescents are more emotionally sensitive to negative events compared to adults, regardless of the valence strength of the events. The current work aimed to confirm this age-related difference in response to emotional stimuli of diverse intensities by examining Electroencephalography (EEG) oscillatory power in time-frequency analysis. Methods: Time-frequency analyses were performed on the EEG data recorded for highly negative (HN), moderately negative (MN) and Neutral pictures in 20 adolescents and 20 adults during a covert emotional task. The results showed a significant age by emotion interaction effect in the theta and beta oscillatory power during the 500–600 ms post stimulus. Results: Adolescents showed significantly less pronounced theta synchronization (ERS, 5.5–7.5 Hz) for HN stimuli, and larger beta desynchronization (ERD; 18–20 Hz) for both HN and MN stimuli, in comparison with neutral stimuli. By contrast, adults exhibited no significant emotion effects in theta and beta frequency bands. In addition, the analysis of the alpha spectral power (10.5–12 Hz; 850–950 ms) showed a main effect of emotion, while the emotion by age interaction was not significant. Irrespective of adolescents or adults, HN and MN stimuli elicited enhanced alpha suppression compared to Neutral stimuli, while the alpha power was similar across HN and MN conditions. Conclusions: These results confirmed prior findings that adolescents are more sensitive to emotionally negative stimuli compared to adults, regardless of emotion intensity, possibly due to the developing prefrontal control system during adolescence.

  8. Classification of spontaneous EEG signals in migraine

    NASA Astrophysics Data System (ADS)

    Bellotti, R.; De Carlo, F.; de Tommaso, M.; Lucente, M.

    2007-08-01

    We set up a classification system able to detect patients affected by migraine without aura, through the analysis of their spontaneous EEG patterns. First, the signals are characterized by means of wavelet-based features, than a supervised neural network is used to classify the multichannel data. For the feature extraction, scale-dependent and scale-independent methods are considered with a variety of wavelet functions. Both the approaches provide very high and almost comparable classification performances. A complete separation of the two groups is obtained when the data are plotted in the plane spanned by two suitable neural outputs.

  9. Dynamic causal modelling of EEG and fMRI to characterize network architectures in a simple motor task.

    PubMed

    Bnstrup, Marlene; Schulz, Robert; Feldheim, Jan; Hummel, Friedhelm C; Gerloff, Christian

    2016-01-01

    Dynamic causal modelling (DCM) has extended the understanding of brain network dynamics in a variety of functional systems. In the motor system, DCM studies based on functional magnetic resonance imaging (fMRI) or on magneto-/electroencephalography (M/EEG) have demonstrated movement-related causal information flow from secondary to primary motor areas and have provided evidence for nonlinear cross-frequency interactions among motor areas. The present study sought to investigate to what extent fMRI- and EEG-based DCM might provide complementary and synergistic insights into neuronal network dynamics. Both modalities share principal similarities in the formulation of the DCM. Thus, we hypothesized that DCM based on induced EEG responses (DCM-IR) and on fMRI would reveal congruent task-dependent network dynamics. Brain electrical (63-channel surface EEG) and Blood Oxygenation Level Dependent (BOLD) signals were recorded in separate sessions from 14 healthy participants performing simple isometric right and left hand grips. DCM-IR and DCM-fMRI were used to estimate coupling parameters modulated by right and left hand grips within a core motor network of six regions comprising bilateral primary motor cortex (M1), ventral premotor cortex (PMv) and supplementary motor area (SMA). We found that DCM-fMRI and DCM-