A case of acquired aphasia and convulsive disorder: some linguistic aspects of recovery and breakdown

Among the cases of acquired aphasia and convulsive disorder several children are reported to have experienced more than one aphasic period. We present such a case in more detail, with emphasis on some characteristics of spontaneous speech. The occurrence of paraphasias, and in particular of neologisms, appeared to be associated with language recovery and breakdown. At the beginning of the period of recovery, a rapid and total disappearance of neologisms was observed, while only literal paraphasias remained. A period of language breakdown was preceded by the return of neologisms. The process was not influenced by drug therapy.     

Clinical validation of a sleep assessment device

We have previously reported on the use of a sleep assessment device (SAD) with non-insomniac subjects. The SAD works by generating a brief, soft tone about every 10 min throughout the night and tape recording verbal responses to these cues. The sleep patterns reconstructed from the night's tape recordings proved highly concordant with EEG records. The present study tested the SAD against the EEG standard in 20 nights of monitoring chronic insomniacs. No significant differences were found between the SAD and EEG records with respect to sleep latency, duration of awakenings during the night, total sleep time and sleep efficiency percentage. The EEG detected many more very brief awakenings during the night than did the SAD due to the continuous monitoring by the former. The SAD proved to be a non-intrusive measure of sleep according to three independent measures. The usefulness of the SAD as a measure of sleep in the natural environment was discussed.     

Relations between psychological stress and EEG correlations

In the present study inquiries have been made about the changes EEG cross-correlation in mental activities is subject to. The EEG recordings were made at rest, in visual and acoustical response, when reading and in the solution of an acoustical differentiation problem. In conjunction with plain reflex processes a decline in the intrahemispherical correlation was observed. During complex-structured psycho-request situations dissimilar changes in the EEG correlation have occurred on the scalp. Between the cerebral regions functionally essential for the solution of the problems, an increase in the bio-electric correlation and between other cerebral areas a decline were registered. The findings in conclusion come to realize that the topographic EEG cross-correlation analysis is appropriate to give an insight into the present situation of cerebral functional organization.     

Summarization of videos by analyzing affective state of the user through crowdsource

Video summarization is one of the key techniques to access and manage a huge chunk of videos. Video summarization is used to extract the effective contents of a video sequence to generate a concise representation of its content. The involvement of crowdsourcing models in recent years is effectively used by researchers in E-commerce domain to increase the quality of the data contents. In this paper, we present a video summarization framework based on users emotion while they watch videos by analyzing cerebral activities through Electroencephalogram (EEG) signals. Three emotions, namely happy, sad and neutral have been extracted from the EEG signals. Video frames have been synchronized with EEG signals and tagged with various emotions. Finally, a crowdsourcing model has been used for effective summarization of the videos. The qualitative assessment of video summarization has been conducted with the help of user ratings using online Google Forms application. EEG signals of 28 users have been recorded while video streams of different emotions. An average accuracy of 83.93% has been recorded in emotion classification using crowdsourcing. Output summarized videos include dynamic video skims and the corresponding audio stream for better understanding.     

Fourier analysis of broad spectral EEG from a fluctuation point of view

It is believed that the EEG is the most reliable method of evaluating brain function, but neither quantitative nor qualitative studies of the EEG have been carried out over the entire range of frequencies. Analysis of limited frequency bands of the EEG has not disclosed the whole of neuronal activity. The aim of this study is to clarify the upper limit of EEG frequency. Our EEG analytic system is composed of a high fidelity preamplifier and signal processor with a frequency response within ?3 dB below 20 kHz. Thirty adult cats were used for these experiments. The upper limit of the frequency varied in different structures: 6.9 ± 0.8 kHz (± SEM) in motor cortex, 4.1 ± 0.3 kHz in the hippocampus, 2.9 ± 0.5 kHz in the amygdala, 9.3 ± 0.6 kHz in the ventrolateral nucleus of the thalamus, and 9.9 ± 0.5 kHz in the midbrain reticular formation. Three different types of amplitude spectra were characterized in bilogarithmic graphs. These types are named types f, f + L, and L corresponding to 1/f or Lorentzian fluctuation. In conclusion, the upper limit of frequency and the spectral types correspond to the neuronal specificity of different brain regions. Their physioanatomic significance is discussed.     

EEG alpha asymmetry and creativity

Results of 3 experiments examining the relationship between creativity and left-hemisphere and right-hemisphere EEG activity are reported. Creativity has been hypothesized to involve the use of primary-process cognition, and such cognition is hypothetically accompanied by activation of the right cerebral hemisphere. In light of these hypotheses, we predicted that highly-creative people should exhibit greater right-hemisphere than left-hemisphere EEG activity during creative performance and that this pattern would not be found in less-creative people. All 3 experiments supported this prediction. This difference in asymmetry was specific to creative performance. It was not present during basal recordings or during a non-creative task.     

Contribution of the speech musculature to apparent human EEG asymmetries prior to vocalization

Vocalizations are preceded by slow EEG waves over inferior frontal scalp regions, but some controversy exists as to whether these slow potentials are left-lateralized as a function of speech. In this study both speech and non-speech vocalizations were studied, under conditions of repetitive and variable production. Averaged responses over the speech musculature, including the temporalis, masseter, orbicularis oris, and mylohyoid muscles, as well as the eyes and tongue, were calculated simultaneously with scalp EEG averages. The responses of the temporalis and masseter muscles, as well as that of the tongue, were correlated with EEG sites at specific latencies prior to speech, suggesting that no part of the inferior frontal EEG record was free from myogenic confounds. In addition, all significant EEG differences between speech and non-speech conditions were subsequently eliminated by covariance analysis, using selected muscle channels as covariates. Previous reports of asymmetrical “speech potentials” in the EEG probably reflected a combination of several myogenic confounds.     

The occurrence of paraphasias in the spontaneous speech of children with an acquired aphasia

Two children with an acquired aphasia were observed during the recovery process. In the spontaneous speech, paraphasias belonging to different categories, such as neologisms, verbal paraphasias, and literal paraphasias, were found. Especially with regard to neologisms the time of investigation was very important. In addition, one child with a phonemic jargon aphasia and one child with a fluent aphasia and empty speech were observed. These observations implicate a modification of the current clinical picture of childhood aphasia. Some aspects are discussed in relation to adult aphasia.     

Arousal and memory: phasic measures of arousal in a free recall task.

EEG alpha activity and skin potential were monitored during word presentation in a single trial free recall task. Phasic changes in EEG alpha and skin potential, co-occurring with word onset, were positively related to recall at an immediate retention interval (2 min) but not after a delay (45 min). The results were interpreted as supporting the extension of Routtenberg's (1968) two-arousal system hypothesis to human memory. Arousal was viewed as affecting memory during the attribute encoding stage of memory storage.     

Pathological left-handedness: Evaluation of a model

This study investigated the relationship between manifest handedness and the localization of EEG abnormalities in a large group of mentally retarded persons. Persons who had abnormal EEG recordings, regardless of whether the dysfunction was bilateral or asymmetric, exhibited approximately twice the incidence of left-handedness than persons who had normal EEG's. Data for persons having asymmetric damage support a model of pathological left-handedness, with left-handers showing a substantially higher probability of having left brain dysfunction than right-handers.     

轻度认知功能障碍患者工作记忆中 脑电能量及皮质联络功能的变化特征

探讨轻度认知功能障碍患者（MCI）工作记忆状态下脑电能量及皮质联络功能的变化特征。被试为从社区选取的35名轻度认知功能障碍患者和34名健康志愿者。采用简单计算回忆方法,结果发现工作记忆加工过程中会引起4.0~18.0Hz范围内功率值的改变,且MCI组高于正常对照组;MCI患者在中央、顶、颞叶的半球间相干系数均显著高于正常对照组。研究结果提示MCI患者可能存在中央、顶、颞叶皮层的功能减退,工作记忆状态下通过代偿机制仍能维持加工的有效性     

Self‐focused cognitive emotion regulation style as associated with widespread diminished EEG fractal dimension

The cognitive regulation of emotions is important for human adaptation. Self‐focused emotion regulation (ER) strategies have been linked to the development and persistence of anxiety and depression. A vast array of research has provided valuable knowledge about the neural correlates of the use of specific self‐focused ER strategies; however, the resting neural correlates of cognitive ER styles, which reflect an individual's disposition to engage in different forms of ER in order to manage distress, are largely unknown. In this study, associations between theoretically negative ER style (self‐focused or not) and the complexity (fractal dimension, FD) of the resting EEG at frontal, central, parietal, and occipital regions were investigated in 58 healthy volunteers. The Cognitive Emotion Regulation Questionnaire was used as the self‐report measure of ER style. Results showed that a diminished FD over the scalp significantly correlated with self‐focused ER style scores, even after controlling for negative affect, which has been also considered to influence the use of ER strategies. The lower the EEG FD, the higher were the self‐focused ER style scores. Correlational analyses of specific self‐focused ER strategies showed that self‐blaming and rumination were negatively associated with diminished FD of the EEG, but catastrophizing and blaming others were not. No significant correlations were found for ER strategies more focused on situation or others. Results are discussed within the self‐organized criticality theory of brain dynamics: The diminished FD of the EEG may reflect a disposition to engage in self‐focused ER strategies as people prone to ruminate and self‐blame show a less complex resting EEG activity, which may make it more difficult for them to exit their negative emotional state.     

Comparison of magneto-and electroencephalographic techniques in event-related response research—a brief survey

Event-related brain potentials are widely used in psychophysiological and neurophysiological research. Recently it has become possible to record weak magnetic fields associated with the electric events of the human brain. In this short survey the magnetoencephalo-graphic (MEG) techniques are compared with the conventional electric measures. MEG and EEG are sensitive to current sources of different orientation. Extracerebral tissues smear and damp the electric potentials but they do not have any significant effect on the magnetic fields. EEG measures potential differences whereas the actual current paths determine the magnetic fields measured outside the skull. In general MEG provides better spatial resolution than the electric recordings, as far as the cortical sources are concerned. It is concluded that EEG and MEG are complementary noninvasive techniques in brain research. As an example slow EEG and MEG shifts preceding voluntary foot movements are compared.     

EEG biofeedback vs. placebo treatment for attention-deficit/hyperactivity disorder: a pilot study

METHOD: Seven children diagnosed with attention-deficit hyperactivity disorder (ADHD) were trained using a standard EEG biofeedback treatment protocol designed to alter SMR/theta ratios and reduce behavioral symptomatology diagnostic of ADHD. During alternate periods they were also trained using a placebo protocol that was identical to the treatment protocol, save that the association between EEG patterns and feedback to the participants was random. Single-case design elements were used to control for the effects of internal validity threats such as maturation, history, and treatment order. Two participants failed to complete all training sessions, and the effects of training on behavior were analyzed both including and excluding these non-completers. RESULTS: When all participants were included in analyses that controlled for overall trend, EEG biofeedback was found to be no more effective than the placebo control condition involving non-contingent feedback, and neither procedure resulted in improvements relative to baseline levels. When overall behavioral trends unrelated to training were not controlled for and non-completers were excluded from the analysis, it could be mistakenly concluded that EEG biofeedback is significantly more effective than placebo and that the effect sizes involved are moderate to large. These results indicate that many previous reports of the efficacy of EEG biofeedback for ADHD, particularly those presenting series of single cases, might well have been based on spurious findings.     

Depression, anxiety, and resting frontal EEG asymmetry: a meta-analytic review

Emotion-related disturbances, such as depression and anxiety, have been linked to relative right-sided resting frontal electroencephalograph (EEG) asymmetry among adults and infants of afflicted mothers. However, a somewhat inconsistent pattern of findings has emerged. A meta-analysis was undertaken to (a) evaluate the magnitude of effects across EEG studies of resting frontal asymmetry and depression, anxiety, and comorbid depression and anxiety and (b) determine whether certain moderator variables could help reconcile inconsistent findings. Moderate effects of similar magnitude were obtained for the depression and anxiety studies, whereas a smaller effect emerged for comorbid studies. Three moderating variables predicted effect sizes: (a) Shorter EEG recording periods were associated with larger effects among adults, (b) different operationalizations of depression yielded effects of marginally different magnitudes, and (c) younger infant samples showed larger effects than older ones. The current data support a link between resting frontal EEG asymmetry and depression and anxiety and provide a partial account of inconsistent findings across studies.     

句子理解过程中句法与语义加工的EEG时频分析

EEG时频分析旨在通过测量单个电极各频段的能量变化, 揭示事件相关振荡活动。采用该技术, 最近的句子加工研究发现, 句法与语义过程均与多个频段(θ、a、b或γ)能量变化相联系。此外, 不同方面的句法(如语法性、数)和语义加工(语义整合或预期)与不同频段振荡活动相联系。将来的研究应该使用多种EEG能量计算方法, 在多种语言中, 探讨时态、词序等句法加工所伴随的振荡活动, 特别是句法和语义过程相互作用在EEG能量变化上的表现。     

Lack of the metabotropic glutamate receptor subtype 7 selectively modulates Theta rhythm and working memory

Metabotropic glutamate receptors (mGluRs) are known to play a role in synaptic plasticity and learning. We have previously shown that mGluR7 deletion in mice produces a selective working memory (WM) impairment, while other types of memory such as reference memory remain unaffected. Since WM has been associated with Theta activity (6-12 Hz) in EEGs, and since EEG abnormalities have been observed in these mice before, we studied the effect of mGluR7 gene ablation on EEG activity in the hippocampus, in particular in the Theta range, during performance of a WM task. In an eight-arm maze with four arms baited, mGluR7 knock-out (KO) and wild-type mice committed the same number of reference memory errors, whereas KOs committed more WM errors. While performing the task, KO mice showed substantially higher Theta amplitudes, and the ratio of Theta to overall EEG power was much increased. No change was seen in the Delta (0-5 Hz), or Gamma (30-40 Hz) EEG bands compared with controls. When recording EEGs during periods of rest in the home cages, no difference was seen between groups. These findings suggest that mGluR7 is important for modulation and control of Theta activity. Since only WM was affected, and only the Theta range of EEG activity was altered, these results show a correlation between Theta rhythm and WM performance, and therefore support the concept that Theta activity in the hippocampus is involved in WM storage.     

Wavelet analysis of neuroelectric waveforms: a conceptual tutorial

This paper presents a nontechnical, conceptually oriented introduction to wavelet analysis and its application to neuroelectric waveforms such as the EEG and event related potentials (ERP). Wavelet analysis refers to a growing class of signal processing techniques and transforms that use wavelets and wavelet packets to decompose and manipulate time-varying, nonstationary signals. Neuroelectric waveforms fall into this category of signals because they typically have frequency content that varies as a function of time and recording site. Wavelet techniques can optimize the analysis of such signals by providing excellent joint time-frequency resolution. The ability of wavelet analysis to accurately resolve neuroelectric waveforms into specific time and frequency components leads to several analysis applications. Some of these applications are time-varying filtering for denoising single trial ERPs, EEG spike and spindle detection, ERP component separation and measurement, hearing-threshold estimation via auditory brainstem evoked response measurements, isolation of specific EEG and ERP rhythms, scale-specific topographic analysis, and dense-sensor array data compression. The present tutorial describes the basic concepts of wavelet analysis that underlie these and other applications. In addition, the application of a recently developed method of custom designing Meyer wavelets to match the waveshapes of particular neuroelectric waveforms is illustrated. Matched wavelets are physiologically sensible pattern analyzers for EEG and ERP waveforms and their superior performance is illustrated with real data examples.     

Modeling development of frontal electroencephalogram (EEG) asymmetry: Sex differences and links with temperament

Asymmetric patterns of frontal brain electrical activity reflect approach and avoidance tendencies, with stability of relative right activation associated with withdrawal emotions/motivation and left hemisphere activation linked with approach and positive affect. However, considerable shifts in approach/avoidance‐related lateralization have been reported for children not targeted because of extreme temperament. In this study, dynamic effects of frontal electroencephalogram (EEG) power within and across hemispheres were examined throughout early childhood. Specifically, EEG indicators at 5, 10, 24, 36, 48, and 72 months‐of‐age (n = 410) were analyzed via a hybrid of difference score and panel design models, with baseline measures and subsequent time‐to‐time differences modeled as potentially influencing all subsequent amounts of time‐to‐time change (i.e., predictively saturated). Infant sex was considered as a moderator of dynamic developmental effects, with temperament attributes measured at 5 months examined as predictors of EEG hemisphere development. Overall, change in left and right frontal EEG power predicted declining subsequent change in the same hemisphere, with effects on the opposing neurobehavioral system enhancing later growth. Infant sex moderated the pattern of within and across‐hemisphere effects, wherein for girls more prominent left hemisphere influences on the right hemisphere EEG changes were noted and right hemisphere effects were more salient for boys. Largely similar patterns of temperament prediction were observed for the left and the right EEG power changes, with limited sex differences in links between temperament and growth parameters. Results were interpreted in the context of comparable analyses using parietal power values, which provided evidence for unique frontal effects.     

Lateral-frontal slow potential shifts preceding language acts in deaf and hearing adults

Slow potential EEG shifts (SPSs) recorded over Broca's area and the paired contralateral site preceding cued language acts have been reported to identify the language-dominant hemisphere. A contingent negative variation paradigm SPS method was applied to the comparative study of 10 hearing adults and of 10 adult prelingually deaf persons whose first learned language was American Sign Language. Volunteers performed both language and non-language acts in both oral and manual expressive modes. The hearing group showed no lateralized SPS, failing to replicate previous reports. The deaf group showed a nonsignificant trend opposite in laterality to that of hearing groups in previous reports.