EEG Alpha Waves Research Articles

Conductive Hydrogel Tapes for Tripolar EEG: A Promising Solution to Paste-Related Challenges.

Electroencephalography (EEG) remains pivotal in neuroscience for its non-invasive exploration of brain activity, yet traditional electrodes are plagued with artifacts and the application of conductive paste poses practical challenges. Tripolar concentric ring electrode (TCRE) sensors used for EEG (tEEG) attenuate artifacts automatically, improving the signal quality. Hydrogel tapes offer a promising alternative to conductive paste, providing mess-free application and reliable electrode-skin contact in locations without hair. Since the electrodes of the TCRE sensors are only 1.0 mm apart, the impedance of the skin-to-electrode impedance-matching medium is critical. This study evaluates four hydrogel tapes' efficacies in EEG electrode application, comparing impedance and alpha wave characteristics. Healthy adult participants underwent tEEG recordings using different tapes. The results highlight varying impedances and successful alpha wave detection despite increased tape-induced impedance. MATLAB's EEGLab facilitated signal processing. This study underscores hydrogel tapes' potential as a convenient and effective alternative to traditional paste, enriching tEEG research methodologies. Two of the conductive hydrogel tapes had significantly higher alpha wave power than the other tapes, but were never significantly lower.

Dynamic cortical and tractography atlases of proactive and reactive alpha and high-gamma activities.

Alpha waves-posterior dominant rhythms at 8-12 Hz reactive to eye opening and closure-are among the most fundamental EEG findings in clinical practice and research since Hans Berger first documented them in the early 20th century. Yet, the exact network dynamics of alpha waves in regard to eye movements remains unknown. High-gamma activity at 70-110 Hz is also reactive to eye movements and a summary measure of local cortical activation supporting sensorimotor or cognitive function. We aimed to build the first-ever brain atlases directly visualizing the network dynamics of eye movement-related alpha and high-gamma modulations, at cortical and white matter levels. We studied 28 patients (age: 5-20 years) who underwent intracranial EEG and electro-oculography recordings. We measured alpha and high-gamma modulations at 2167 electrode sites outside the seizure onset zone, interictal spike-generating areas and MRI-visible structural lesions. Dynamic tractography animated white matter streamlines modulated significantly and simultaneously beyond chance, on a millisecond scale. Before eye-closure onset, significant alpha augmentation occurred at the occipital and frontal cortices. After eye-closure onset, alpha-based functional connectivity was strengthened, while high gamma-based connectivity was weakened extensively in both intra-hemispheric and inter-hemispheric pathways involving the central visual areas. The inferior fronto-occipital fasciculus supported the strengthened alpha co-augmentation-based functional connectivity between occipital and frontal lobe regions, whereas the posterior corpus callosum supported the inter-hemispheric functional connectivity between the occipital lobes. After eye-opening offset, significant high-gamma augmentation and alpha attenuation occurred at occipital, fusiform and inferior parietal cortices. High gamma co-augmentation-based functional connectivity was strengthened, whereas alpha-based connectivity was weakened in the posterior inter-hemispheric and intra-hemispheric white matter pathways involving central and peripheral visual areas. Our results do not support the notion that eye closure-related alpha augmentation uniformly reflects feedforward or feedback rhythms propagating from lower to higher order visual cortex, or vice versa. Rather, proactive and reactive alpha waves involve extensive, distinct white matter networks that include the frontal lobe cortices, along with low- and high-order visual areas. High-gamma co-attenuation coupled to alpha co-augmentation in shared brain circuitry after eye closure supports the notion of an idling role for alpha waves during eye closure. These normative dynamic tractography atlases may improve understanding of the significance of EEG alpha waves in assessing the functional integrity of brain networks in clinical practice; they also may help elucidate the effects of eye movements on task-related brain network measures observed in cognitive neuroscience research.

Study of EEG alpha wave response on the effects of video-guided deep breathing on pain rehabilitation.

Athletes with chronic ankle pain (CAP) are more inclined to suffer from physical and psychological pain depending on the severity of the injuries, which might trigger the powerless feeling on future sports participation. Therefore, an efficient and simple method is useful to integrate into conventional physiotherapy (CP) for maintaining mental wellness. This research aimed to verify the effects and progress of video-guided deep breathing (DB) integrated into CP through study on the changes of alpha waves and pain scale. Alpha waves were recorded using an electroencephalogram (EEG) and a visual analogue scale (VAS) to assess pain intensity before and after the intervention (6weeks). Thirty CAP participants were recruited and randomly assigned to two groups: group A for video-guided DB integration into their CP and group B for CP. The effects of pre and post intervention were analyzed using a paired t-test with statistical significance set at p< 0.05. Profound results from the research have shown that the participants who received both the DB+CP revealed a significant increase in alpha wave (p< 0.05) at occipital region. The significant result reveals an increase in alpha waves in the occipital region after 6weeks and indicates that the video-guided DB with a smartphone application is able to produce a change in CAP participants. This supports the DB integration to the CP for altering the pain perception.

Infrared Radiation of Graphene Electrothermal Film Triggered Alpha and Theta Brainwaves

The alpha and theta frequency brainwave activity in electroencephalogram (EEG) signal is proven to correlate with attention, inhibitory processes, memory, perceptual abilities, and sleep. The decreasing of brainwaves is demonstrated to be the reason of aging and even Alzheimer's disease, so triggering alpha and theta brainwave activity may bring positive behavioral modifications such as promoting health care and a quick sleep. Herein, it is discovered that infrared radiation from multilayer graphene electrothermal film can obviously promote the appearance of alpha and theta brainwaves in the human brain. In particular, the occurrence frequency and duration time of the alpha and theta waves in EEG can be effectively enhanced up to 2.3/2.9 and 3.0/4.1 times, respectively. The comparative effect of different working temperatures and heating materials is systematically investigated, indicating efficient infrared radiation from the multilayer graphene electrothermal film, which coincides with the human‐body thermal‐radiation wavelength range from 7 to 14 μm, may be the main mechanism for this enhancement. The multilayer graphene film electrical heater represents a convenient and surprising way for triggering alpha and theta brainwaves, which has many potential applications in the area of enlarged healthcare requirements.

Health Effects of 5G Base Station Exposure: A Systematic Review

The Fifth Generation (5G) communication technology will deliver faster data speeds and support numerous new applications such as virtual and augmented reality. The additional need for a larger number of 5G base stations has sparked widespread public concerns about their possible negative health impacts. This review analyzes the latest research on electromagnetic exposure on humans, with particular attention to its effect on cognitive performance, well-being, physiological parameters, and Electroencephalography (EEG). While most of their results indicated no changes in cognitive function, physiological parameters, or overall well-being, the strength of the EEG alpha wave is noticed to vary depending on various aspects of cognitive functions. However, the available studies have not investigated the health effects resulting from exposure from the 5G mobile phone and base station antennas from 700 MHz to 30 GHz on the cognitive performance, well-being subjective symptoms, human physiological parameters, and EEG of adults. There is a need for such research regarding this current emerging technology. Such studies are significant in determining whether 5G technology is indeed safe for humans.

Relaxation Effects of Essential Oils Are Explained by Their Interactions with Human Brain Neurotransmitter Receptors and Electroencephalography Rhythms.

Inhaled essential oils (EOs) are bioavailable to the brain and are consistently reported to promote relaxation effects. Their mechanisms of action are however not well understood. The aim of this investigation was to assess the neuroactivity of EOs based on their (i) binding interactions to neurotransmitter receptors and (ii) bioelectrical activities in the brain as measured by electroencephalography (EEG). These EO properties were compared to those of reference pharmaceutical compounds with effects also measured by EEG. Relative receptor binding efficacies of 10 reference compounds, 180 EOs, and 9 EO extracts with 7 different neurotransmitter receptors were calculated using in silico molecular docking procedures. Changes in brain EEG rhythms, as standardized changes in absolute power, were determined for the reference compounds and selected EOs and compared to receptor binding efficacy results. The reference compounds had diverse receptor binding patterns, with EEG responses dominated by EEG-delta wave frequencies. In contrast, the receptor binding pattern of the EOs was remarkably consistent and replicated a subclinical affinity pattern corresponding to the inhibitory glycine-α-GLRA3 and dopamine-D2 receptors, producing responses dominated by EEG-alpha wave frequencies. The results support the hypothesis that EOs stimulate neuroactivity by modulating patterns of neurotransmission affecting alpha wave EEG responses.

The Effects of 3D and 2D Imaging on Brain Wave Activity in Laparoscopic Training

The current study tested the effects of a state-of-the-art stereoscopic three-dimensional (3D) display and a traditional two-dimensional (2D) display on performance and mental workload during simulated laparoscopic tasks with different levels of depth perception over a longer duration than in previous publications. Two different simulated laparoscopic tasks with depth perception, peg transfer, and circle-tracing were performed by 12 participants using 2D and 3D vision systems. The task performances (mean completion time and mean error frequency) and mental workload measures (gamma and alpha brain wave activity, blink frequency and NASA-TLX ratings) were recorded as dependent variables. The physiological mental workload measures were collected via a MUSE EEG headband. The 3D vision system had advantages in mean movement time and mean error frequency in the depth-perception peg transfer task. The mean completion time of the non-depth perception circle-tracing task was significantly lower for 2D than for 3D. For the peg transfer task, EEG alpha wave activity was significantly higher for 3D than for 2D. The EEG gamma wave activity for 2D was significantly higher than that for 3D in both tasks. A significantly higher blink frequency was found for both the peg transfer task and the 3D system. The overall NASA-TLX score of the 2D system was significantly higher. The findings of this research suggest that a 3D vision system could decrease stress, state of attentiveness, and mental workload compared with those of a 2D system, and it might reduce the completion time and increase the precision of depth-perception laparoscopic operations.

Impact of preksha meditation on alpha waves in EEG

Aims: The present study aims at demonstrating changes in alpha wave frequency on electroencephalograph (EEG) at two and four months of preksha meditation training in young novice students. Materials and Methods: Participants included 52 girls between the 17 to 21 years of age from a local college selected using a convenience sampling technique. They were randomly divided into experimental (n = 29) and control (n = 26) groups. Study duration was 4 months during which experimental group was administered a supervised PM training for 4 months. During this period control group continued their normal activities without mediation practice. EEG was analyzed for alpha waves and compared at base line, at 2 months and at 4 months. Results: The mean value of alpha wave frequency (%) in control group at beginning was 49.65 ±21.598 which increased to 52.58±18.005 at 2 months. In experimental group, in beginning it was 49.52 ±18.169 which increased to 54.31±22.490 at 2 months. However, this increment was not statistically significant in both groups. A statistically significant increment in alpha waves percentage to 66.59±9.493 was observed in experimental group after four months of PM which was significant at the level of p Conclusions: A significant increase in alpha waves was observed at 4 months of PM practice in young novice students. This increase was observed at 4 months and not at 2 months suggesting that longer practice of meditation is needed to bring out significant improvement. Keywords: Preksha meditation, EEG, Alpha waves.

Changes in the Electrical Activity of the Brain in the Alpha and Theta Bands during Prayer and Meditation.

Focused attention meditation (FAM) is a category of meditation based on an EEG pattern, which helps the wandering mind to focus on a particular object. It seems that prayer may, in certain respects, be similar to FAM. It is believed that emotional experience correlates mainly with theta, but also with selective alpha, with internalized attention correlating mainly with the synchronous activity of theta and alpha. The vast majority of studies indicate a possible impact of transcendence in meditation on the alpha wave in EEG. No such reports are available for prayer. Seventeen women and nineteen men aged 27–64 years with at least five years of intensive meditation/prayer experience were recruited to participate in the study. We identified the two largest groups which remained in the meditation trend originating from the Buddhist system (14 people) (Buddhist meditators) and in the Christian-based faith (15 people) (Christian meditators). EEG signal was recorded with open eyes, closed eyes, during meditation/prayer, and relaxation. After the EEG recording, an examination was conducted using the Scale of Spiritual Transcendence. Buddhist meditators exhibited a statistically significantly higher theta amplitude at Cz during meditation compared to relaxation. Meanwhile, spiritual openness favored a higher theta amplitude at Pz during relaxation. Our study did not reveal statistically significant differences in frontal areas with regard to alpha and theta, which was often indicated in previous studies. It seems necessary to analyze more closely the midline activity in terms of dispersed neural activity integration.

Too Real to Be Virtual: Autonomic and EEG Responses to Extreme Stress Scenarios in Virtual Reality.

The evolution of virtual reality (VR) technologies requires setting boundaries of its use. In this study, 3 female participants were experiencing VR scenarios with stressful content and their activity of the autonomic nervous system and EEG were recorded. It has been discovered that virtual reality can evoke acute stress reactions accompanied by activation of the sympathetic nervous system and a decrease in the activity of the parasympathetic nervous system. The high-stress response is accompanied by a decrease in the power of the EEG, and, on the contrary, the activation of the avoidance reaction is accompanied by an increase in the power of the EEG alpha waves. Therefore, the use of stressful VR content can cause high emotional stress to a user and restrictions should be considered.

Effect of fixed dental prosthesis on the brain functions of partially edentulous patients - pilot study with power spectrum density analysis.

This study was done to analyse the influence of fixed dental prosthesis (FDP) on brain function by analysing power spectral density of partially edentulous patients. The study included unilateral missing mandibular molar replacement patients. The patients were restored with three-unit metal ceramic FDP restorations. The cognitive function was analysed with a mental state questionnaire. Power spectral density (PSD) analysis of EEG alpha waves was made pre- treatment, post treatment and 3 months after FDP treatment to analyse the brain function. The data in various phases were obtained before and after chewing. The results were statistically analysed. The mean pre and post treatment PSD was 0.0175 (SD ±0.0132) and 0.0178 (SD ±0.0135). The mean post treatment PSD after three months was 0.024 (SD± 0.019). The results were analysed with repeated ANOVA and were statistically significant. (p<0.01). The study displayed improvement in brain function of partially edentulous patients with FDP rehabilitation.

Caffeine Increased Muscle Endurance Performance Despite Reduced Cortical Activation and Unchanged Neuromuscular Efficiency and Corticomuscular Coherence.

The central and peripheral effects of caffeine remain debatable. We verified whether increases in endurance performance after caffeine ingestion occurred together with changes in primary motor cortex (MC) and prefrontal cortex (PFC) activation, neuromuscular efficiency (NME), and electroencephalography–electromyography coherence (EEG–EMG coherence). Twelve participants performed a time-to-task failure isometric contraction at 70% of the maximal voluntary contraction after ingesting 5 mg/kg of caffeine (CAF) or placebo (PLA), in a crossover and counterbalanced design. MC (Cz) and PFC (Fp1) EEG alpha wave and vastus lateralis (VL) muscle EMG were recorded throughout the exercise. EEG–EMG coherence was calculated through the magnitude squared coherence analysis in MC EEG gamma-wave (CI > 0.0058). Moreover, NME was obtained as the force–VL EMG ratio. When compared to PLA, CAF improved the time to task failure (p = 0.003, d = 0.75), but reduced activation in MC and PFC throughout the exercise (p = 0.027, d = 1.01 and p = 0.045, d = 0.95, respectively). Neither NME (p = 0.802, d = 0.34) nor EEG–EMG coherence (p = 0.628, d = 0.21) was different between CAF and PLA. The results suggest that CAF improved muscular performance through a modified central nervous system (CNS) response rather than through alterations in peripheral muscle or central–peripheral coupling.

주거공간의 색채계획에 대한 노인거주자의 심리 · 생리 반응 : 노인의 우울특성에 따른 비교연구

The purpose of this study is to propose the desirable color scheme of living room in relation to the depressive symptoms of the elderly residents. The elderly are more likely to progress depressive symptoms due to physical, psychological, and economic changes. This study is to clarify the relationship between color planning and depression so as to find out effective color design scheme on the improvement of depressions. 87 elderly residents over 65 years participated the experiments and they were classified into two groups: group A portrayed under 14 points, normal, and group B portrayed over 15 points, slight, moderate, or serious depression, as to the results of the KGDS. Their psychological and physiological responses to the nine images of the residential space - one achromatic color combination, warm and cool analogous color combinations and complementary color combinations of 50% and 100% ratio of faced wall - were analyzed and compared. The psychological response was measured by SD scale composed of the six pairs of adjectives, and the physiological response by the EEG alpha wave asymmetry of the prefrontal cortex. Psychological responses of group A has shown positive feedback to the R-YR (100), while group B has shown the R-G (100). Physiologically group A responded positively to the R-YR (100), and group B responded positively to the PB-Y (100). Group A seemed to prefer warm analogous color combination psychologically and physiologically. Group B seemed to prefer the complementary color combination rather than the analogous color combination.

T117. The effects of Transcranial Alternating Current Stimulation (tACS) at Individual Alpha Peak Frequency (iAPF) on motor cortex excitability of young and elderly adults

Transcranial alternating current stimulation (tACS) was shown to modulate brain oscillation, cortical excitability and behaviour. This technique allows for the direct perturbation of brain oscillation such as the EEG alpha wave (8–12 Hz). In aging, there is correlation between the decrease in alpha activity and the profound cognitive and motor impairments. Studies suggest a state-dependent effect of tACS on alpha activity: upregulation of alpha oscillations only occurs in conditions of low alpha power (e.g. in the elderly). The present study aimed at further exploring the state-dependent effect of tACS on cortical excitability. We applied tACS at individual alpha peak frequency (iAPF) for 10 min (1.5 mA) to the left motor cortex of healthy young and old volunteers. Transcranial magnetic stimulation (TMS) was used to assess the changes in cortical excitability as measured by motor evoked potentials (MEP) at rest before and after stimulation. TACS increased cortical excitability in both groups. This indicates that the effect was not state-dependent. However, our results also suggest that the mechanism behind the effects was different, as we observed an increase in intracortical inhibition in the old group and a decrease in inhibition in the young group. Our results point to tACS as a potential approach to compensate the decline in alpha activity and to improve cognitive and motor function in the elderly.

Effect of Type 2 Diabetes Mellitus on Cognitive function and EEG in elderly patients

Introduction: Diabetes is a major health problem in India, Type 2 is also the most common type seen. Diabetes is associated with cognitive decline in elderly patients. Hyperglycemia, age, sex and duration of diabetes mellitus all seems to affect cognitive function.&#x0D; Objectives: Aim of the study is to assess the EEG changes and cognitive function in elderly type 2 diabetes mellitus patients.&#x0D; Materials and methods: Two groups of people, 20 in each group who are age sex matched were selected and case group of elderly diabetic patients and control group of healthy subjects were selected. EEG recordings were done using MP36 – BIOPAC 4 channel instrument and cognitive function was assessed using MMSE.&#x0D; Results: The elderly diabetic group was having declined cognitive function – MCI (Mild Cognitive Impairment) and reduced EEG wave activity.&#x0D; Conclusion: Reduced EEG alpha wave activity is seen in elderly diabetic patients. Reduced functional connections in cortex and hyperglycemia induced pathologic changes could be the causative factors.

Direct effects of transcranial electric stimulation on brain circuits in rats and humans

Transcranial electric stimulation is a non-invasive tool that can influence brain activity; however, the parameters necessary to affect local circuits in vivo remain to be explored. Here, we report that in rodents and human cadaver brains, ~75% of scalp-applied currents are attenuated by soft tissue and skull. Using intracellular and extracellular recordings in rats, we find that at least 1 mV/mm voltage gradient is necessary to affect neuronal spiking and subthreshold currents. We designed an ‘intersectional short pulse’ stimulation method to inject sufficiently high current intensities into the brain, while keeping the charge density and sensation on the scalp surface relatively low. We verify the regional specificity of this novel method in rodents; in humans, we demonstrate how it affects the amplitude of simultaneously recorded EEG alpha waves. Our combined results establish that neuronal circuits are instantaneously affected by intensity currents that are higher than those used in conventional protocols.

Partnering With Black Churches to Increase Access to Care.

Partnering With Black Churches to Increase Access to Care.

Nonlinear Recurrent Dynamics and Long-Term Nonstationarities in EEG Alpha Cortical Activity: Implications for Choosing Adequate Segment Length in Nonlinear EEG Analyses.

Nonlinear analysis of EEG recordings allows detection of characteristics that would probably be neglected by linear methods. This study aimed to determine a suitable epoch length for nonlinear analysis of EEG data based on its recurrence rate in EEG alpha activity (electrodes Fz, Oz, and Pz) from 28 healthy and 64 major depressive disorder subjects. Two nonlinear metrics, Lempel-Ziv complexity and scaling index, were applied in sliding windows of 20 seconds shifted every 1 second and in nonoverlapping windows of 1 minute. In addition, linear spectral analysis was carried out for comparison with the nonlinear results. The analysis with sliding windows showed that the cortical dynamics underlying alpha activity had a recurrence period of around 40 seconds in both groups. In the analysis with nonoverlapping windows, long-term nonstationarities entailed changes over time in the nonlinear dynamics that became significantly different between epochs across time, which was not detected with the linear spectral analysis. Findings suggest that epoch lengths shorter than 40 seconds neglect information in EEG nonlinear studies. In turn, linear analysis did not detect characteristics from long-term nonstationarities in EEG alpha waves of control subjects and patients with major depressive disorder patients. We recommend that application of nonlinear metrics in EEG time series, particularly of alpha activity, should be carried out with epochs around 60 seconds. In addition, this study aimed to demonstrate that long-term nonlinearities are inherent to the cortical brain dynamics regardless of the presence or absence of a mental disorder.

Frontal EEG-α波のBFTに関する研究 : 第4報

Frontal EEG-α波のBFTに関する研究 : 第4報

아쿠아로빅스 운동이 노인 여성의 전두엽 뇌전위 알파파 활성과 치매관련인자에 미치는 영향

아쿠아로빅스 운동이 노인 여성의 전두엽 뇌전위 알파파 활성과 치매관련인자에 미치는 영향