Total EEG Power Research Articles

Curative intent chemotherapy-induced alterations in specific qEEG markers of cognition in patients with breast cancer

Objectives: Chemotherapy-induced cognitive impairment is a gruesome outcome of chemotherapy among breast cancer survivors. Electroencephalogram (EEG) power measurement is a known sensitive neurophysiologic correlate of cancer treatment-related cognitive dysfunction. The objective of this study was to assess the changes in specific quantitative EEG markers of cognition among breast cancer patients before, immediately, and three months after chemotherapy. Materials and Methods: Twenty-three women planning to undergo adjuvant chemotherapy for breast cancer underwent EEG assessment before, immediately, and three months after chemotherapy. Repeated measures analysis of variance was used to analyse the data. Post hoc pairwise comparison was done with Bonferroni correction to determine the pair in which the difference existed. Results: A significant increase in resting state EEG total power was observed (P = 0.012) after chemotherapy in the frontal area. The relative alpha power (RAP) significantly decreased with chemotherapy (P = 0.039), with post hoc pairwise comparison with Bonferroni correction revealing the significant decline to be present immediately after chemotherapy (P = 0.036) only over the posterior channels. Furthermore, the alpha-to-theta ratio (ATR) over posterior areas decreased (P = 0.012) both after completion of chemotherapy (P = 0.039) as well as three months after chemotherapy (P = 0.048). However, similar changes were not observed over frontal areas. Conclusion: Chemotherapy induces enhanced frontal power with a coincidental decline in RAP and ATR in the posterior areas.

Electroencephalographic density spectral array monitoring during propofol/sevoflurane coadministration in children, an exploratory observational study

IntroductionPropofol and sevoflurane have a long history in pediatric anesthesia. Combining both drugs at low dose levels offers new opportunities. However, monitoring the hypnotic effects of this drug combination in children is challenging, because the currently available processed EEG-based systems are insufficiently validated in young children and the co-administration of anesthetics. This study investigated electroencephalographic density spectral array monitoring during propofol/sevoflurane coadministration with fixed sevoflurane- and variable propofol dosages. Patients and methodsWe analyzed the density spectral array pattern recorded during propofol/sevoflurane anesthesia in pediatric patients from birth to 11 years of age. Data from 78 patients were suitable for analysis. The primary outcome parameter of this study was the correlation between variable propofol dosages and the expression of the four electroencephalogram frequency bands β, α, θ, and δ. The main secondary outcome parameters were the intra-operative total EEG power and the prevalence of burst suppression. ResultsIn patients above the age of 1 year, a dose-dependent correlation between the propofol dosage and the relative percentage of β (−12.2%, p < 0.001) and δ (5.1%, p < 0.001) was found. There was an age-dependent trend toward increasing mean EEG power, with the most significant increase in the first year of life. In 14.1% of our patients, at least one episode of burst suppression occurred. ConclusionDSA-guided augmentation of propofol anesthesia with sevoflurane provides sufficient depth of anesthesia at doses usually considered sub-anesthetic in children, leading to less anesthetic drug exposure for the individual child.

Predictors of Low Risk for Delirium during Anesthesia Emergence.

Processed EEG is used to monitor the level of anesthesia and it has shown the potential to predict the occurrence of delirium. While emergence trajectories of relative eeg band power identified post-hoc show promising results in predicting a risk for a delirium, they are not easily transferable into an online predictive application. In this article we describe a low-resource and easily applicable method to differentiate between patients at high risk and low risk for delirium, with patients at low risk expected to show decreasing eeg power during emergence. We included data from 169 patients (median age: 61 [49, 73]), who underwent surgery with general anesthesia, maintained either with propofol, sevoflurane, or desflurane. The data were derived from a previously published study. We chose a single frontal channel and calculated the total and spectral band power from the EEG and calculated a linear regression model to observe the parameters' change during anesthesia emergence, described as slope. The slope of total power and single band power was correlated with the occurrence of delirium. Of 169 patients, 32 (19%) showed delirium. We observed that patients whose total EEG power diminished the most during emergence were less likely to screen positive for delirium in the PACU. A positive slope in total power and band power evaluated by using a regression model was associated with a higher risk-ratio (total: RR 2.83 (95%CI: 1.46 to 5.51) alpha/beta band: RR 7.79 (95%CI: 2.24 to 27.09)) for delirium. Furthermore, a negative slope in multiple bands during emergence was specific for patients without delirium and allowed to define a test for patients at low risk. In this study we developed an easily applicable exploratory method to analyze a single frontal EEG channel and to identify patterns specific for patients at low risk for delirium.

Anti-Apoptotic Effects of AMPA Receptor Antagonist Perampanel in Early Brain Injury After Subarachnoid Hemorrhage in Mice.

This study was aimed to investigate if acute neuronal apoptosis is induced by activation of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionate) receptors (AMPARs) and inhibited by a clinically available selective AMPAR antagonist and antiepileptic drug perampanel (PER) in subarachnoid hemorrhage (SAH), and if the mechanisms include upregulation of an inflammation-related matricellular protein periostin. Sham-operated and endovascular perforation SAH mice randomly received an administration of 3mg/kg PER or the vehicle intraperitoneally. Post-SAH neurological impairments and increased caspase-dependent neuronal apoptosis were associated with activation of AMPAR subunits GluA1 and GluA2, and upregulation of periostin and proinflammatory cytokines interleukins-1β and -6, all of which were suppressed by PER. PER also inhibited post-SAH convulsion-unrelated increases in the total spectral power on video electroencephalogram (EEG) monitoring. Intracerebroventricularly injected recombinant periostin blocked PER's anti-apoptotic effects on neurons. An intracerebroventricular injection of a selective agonist for GluA1 and GluA2 aggravated neurological impairment, neuronal apoptosis as well as periostin upregulation, but did not increase the EEG total spectral power after SAH. A higher dosage (10mg/kg) of PER had even more anti-apoptotic effects compared with 3mg/kg PER. Thus, this study first showed that AMPAR activation causes post-SAH neuronal apoptosis at least partly via periostin upregulation. A clinically available AMPAR antagonist PER appears to be neuroprotective against post-SAH early brain injury through the anti-inflammatory and anti-apoptotic effects, independent of the antiepileptic action, and deserves further study.

Research on the Preferred Illuminance in Office Environments Based on EEG

The quality of the indoor light environment in buildings directly influences the emotional state, health condition, and work efficiency of people. The application of EEG to indoor light environments is beneficial to further reveal the neural mechanisms of light comfort. In this study, the absolute power of spontaneous EEG was calculated as an objective physiological index, and its trend with the illuminance level of the task area was analyzed. Then, the absolute power of the band, which has the strongest correlation with subjective evaluation and task performance, was selected as the characteristic value. The subjective and objective parameters were validated to explore the preferred illuminance choices for subjects’ comfort and efficiency during the rest stage and the task stage, respectively. The results showed that the power of the δ band and β band at partial channels in the parietal region had statistically significant differences under five illuminance levels in the resting state. The total logarithmic power of EEG and the logarithmic power of the δ band at the Cz channel were negatively correlated with the subjective evaluation. The total logarithmic power of EEG was relatively low when the subjective evaluation was comfortable. There was no statistical difference in the total EEG logarithmic power among the five illuminance levels in the task state, but the subjects had the highest performance indicator and the best cognitive task performance at 500 lux and 750 lux conditions. This research may provide a design reference for the selection of task area illuminance levels for staff during high-intensity mental work and rest.

Evaluation of a commercial electrical stunning method for farmed grower saltwater crocodiles (Crocodylus porosus) using non-invasive EEG measurements.

The aim of this study was to assess welfare outcomes of electrical stunning as a means of restraint in farmed grower saltwater crocodiles (Crocodylus porosus). Physical handling of a stunned, unconscious crocodile is far safer for the operator than handling a fully conscious animal. Electroencephalogram (EEG) was recorded before and after the application of electrical stunning at 50 Hz or 400 Hz using an electrical stunner applied to the cranial plate (Position 1: P1-50 Hz; n = 31, P1-400 Hz; n = 29) or immediately behind the skull (Position2: P2-50 Hz; n = 29; P2-400 Hz; n = 30). For all electrical stuns, percentage total EEG power in a 10-s epoch decreased in the alpha and beta frequency bands; and increased in the delta and lower frequencies bands. All electrical stuns resulted in increased strength of signal, based on the quadratic mean EEG power in all frequency bands of the EEG. Greatest change in power occurred in the delta frequency band, with P1-50 Hz. This was greater than with P2-50 Hz; while decibel change using 400 Hz at either position was intermediate and not significantly different from either. Application of either electrical stunner at position 1 resulted in seizure-like activity and activation in low frequencies, but at position 2 this was not consistent across all animals. The ability of the electrical stunning equipment to consistently induce recoverable unconsciousness could be ranked in decreasing order as: P1-50 Hz > P1-400 Hz = P2-50 Hz > P2-400 Hz. Based on behavioural observations, all animals in the study appeared to stunned however evaluation of duration of EEG changes indicates that use of the electrical stunning equipment at 50 Hz would allow some margin for inaccuracies in tong placement, while achieving a consistently reliable stun.

Different effects of air microembolism through patent foramen ovale in patients with migraine: A quantitative electroencephalogram case series.

Literature suggests an association between patent foramen ovale (PFO) and migraine, mostly migraine with aura (MA). Previous data suggest that air microembolism through PFO can lead to bioelectrical abnormalities detectable at electroencephalogram (EEG) in patients with MA, thus suggesting a pathophysiological mechanism for the MA-PFO association. However, those data lack replication. Patients with MA or migraine without aura (MO) and large PFO underwent a 19-channel EEG recording before and after injection of air microbubbles. We compared EEG power before and after microbubble injection for each electrode location, for each frequency band (theta: 5-7 Hz; alpha: 8-12 Hz; beta: 13-30 Hz; lower gamma: 31-45 Hz), and for total global power (the average of EEG power at each location and frequency band). We included 10 patients, four with MA and six with MO; six patients had medium-to-high migraine frequency (four or more monthly migraine days), while four had low frequency (one monthly migraine day). EEG power changes after air microembolism varied across patients. Considering the overall group, total global EEG power did not change; however, EEG power in the higher frequency ranges (beta and lower gamma) increased in patients with MA. We did not replicate the effects of air microembolism previously reported in patients with migraine. Aura status, migraine frequency, and medications might influence patients' response to microembolism. More refined EEG measurements are needed to clarify the dynamic role of PFO on migraine occurrence.

QEEG‐based differentiation between Alzheimer’s disease with or without alpha synucleinopathy

AbstractBackgroundAs existence of alpha synucleniopathy could affect progression of cognitive impairment in Alzheimer’s disease (AD), it’s very important to differentiate comorbidity of alpha synucleniopathy in AD to predict progression. To develop affordable EEG‐based discriminating machine‐learning(ML) algorithm for existence of alpha synucleniopathy, we explore differences between AD with vs without it.MethodBased on pattern of cognitive impairment and 3 types of PET scan [18F‐Florbetaben brain amyloid‐beta, FDG, DAT‐PET] , dementia due to Alzheimer’s disease [pure ADD] or Lewy Body (pure LBD) or mixed type (AD with LB disease) were clinically classified.We measured 19ch resting state EEG based on international 10‐20. Quantitative analysis of EEG was done by iSyncBrain®.ResultPure ADD showed the characteristics that general EEG slowing with low total power, relative delta enhancement and desynchronized alpha with low amplitude. Pure LBD showed the pattern of slow alpha peak frequency with intact synchronization, relatively higher EEG total power and frontotemporal theta enhancement. Compared to pure ADD, ADD with LB showed mixed pattern of ADD and LDB. Total power was higher, alpha wave showed intact synchronization but theta power was rather enhanced at frontal(Fz; p‐value &lt; 0.05) and bilateral temporal(T3,5, T4,6; p‐value &lt; 0.05) area that was reported as characteristic pattern of progressive type of AD by previous studies.ConclusionThese findings imply that ADD could have different EEG oscillation characteristics according to the Lewybody disease. Next step, we will develop the machine‐learning algorithm to discriminate the Lewybody disease based on specific EEG features and validate it.

Effects of exercise on the sleep microarchitecture in the aging brain: A study on a sedentary sample.

Having a healthy sleep pattern plays a vital role in one's overall health. Sleep in the elderly is characterized by decreased slow-wave sleep and an increase of REM sleep. Furthermore, quantitative electroencephalographic (qEEG) studies have shown an age-related attenuation of total EEG power in sleep. However, exercise has been shown to improve sleep across all age groups. In this study, we used the Sleep Profiler™ EEG Sleep Monitor to observe EEG changes occurring during sleep following an aerobic exercise intervention. This study was done on older adults (N = 18, with only five subjects containing both pre- and post-data of sufficient quality for analysis) with an age range 60-85 years. The aerobics regimen was performed three times weekly for 12-weeks commencing with 20-min sessions. The time of each session progressed by 1-2 min/session as needed to a maximum time of 45 min per session. The macro-architecture (sleep stages) and microarchitecture (EEG) results were analyzed using MATLAB. For the microarchitecture, our results showed more deep sleep following the aerobic exercise regimen. Furthermore, for the microarchitecture, out results shows an increase in total EEG power post-exercise in both light (N1 and L1) and deep sleep (N2 and N3). These preliminary changes in sleep the microarchitecture suggest that non-pharmacologic methods might mitigate age-related EEG changes with potential implications for neurocognitive health.

Effects of Different Extinction for Morphine-CPP on Hippocampal EEG Power Spectrum in Mice

The relationship between hippocampal electroencephalogram (EEG) power spectrum and the extinction of addiction memory was investigated. Forty KM mice (Kunming mice) that had successfully established morphine (MOR)-conditioned place preference (CPP) were divided into four groups: saline-training extinction (SAL-TE), SAL-natural extinction (SAL-NE), MOR-TE, MOR-NE, for extinction treatment and EEG recording in the dorsal and ventral hippocampus (DH/VH). Results show that the CPP score of MOR-TE significantly decreased and the total, β and γ bands power spectrum of MOR-TE was suppressed. Notably, the total power from the VH was more correlated with the extinction method, and the TE total power was always lower than NE in SAL or MOR group. Naloxone enhanced the EEG total power and all bands (DH) or β and γ bands (VH) power in the SAL group. However, in the MOR-TE group, only β and γ bands power in VH increased (P&lt;0.05). The results suggest that TE can promote the extinction of opiate addictive memory more effectively than NE, and the extinction of MOR-CPP may have a stronger correlation with changes of VH-EEG power spectrum.

ЕЕГ-ознаки ризику розвитку симптомного інсульту в пацієнтів із множинними «німими» інфарктами мозку

У статті наведені дані дослідження ЕЕГ-корелятів порушення церебрального кровообігу та їх зв’язку з ризиком виникнення інсульту в пацієнтів із множинними «німими» інфарктами мозку (мНІМ). Аналіз біоелектричної активності мозку був проведений у 36 пацієнтів (середній вік 54,00 ± 3,22 року) із МРТ-ознаками поодинокого НІМ (пНІМ) та в 24 пацієнтів (середній вік 67,89 ± 1,84 року) із МРТ-ознаками мНІМ. Протягом року після ЕЕГ-дослідження в 4 пацієнтів із мНІМ стався симптомний інсульт. У пацієнтів із мНІМ числові показники ЕЕГ-корелятів порушення церебрального кровообігу значно відрізнялися від таких пацієнтів із пНІМ. Порівняно з пацієнтами з групи пНІМ для картини ЕЕГ пацієнтів із мНІМ було притаманне значне зниження спектральної потужності (за коефіцієнтом α/δ), щільності (14,87 ± 2,83 та 1,89 ± 0,49 мкВ2/Гц відповідно, р &lt; 0,001) та індексу (39,18 ± 2,96 та 11,65 ± 1,17 % відповідно, р &lt; 0,001) α-ритму на тлі зростання аналогічних показників δ-ритму. Загальна спектральна потужність ЕЕГ у пацієнтів групи мНІМ була в 2,3 раза нижчою, ніж у пацієнтів групи пНІМ (124,81 ± 18,24 та 285,03 ± 35,71 мкВ2 відповідно, р &lt; 0,001), коефіцієнт потужності α/δ — у 7 разів меншим (0,35 ± 0,05 та 2,49 ± 0,34 відповідно, р &lt; 0,001), а (δ + θ)/(α + β)-коефіцієнт — у 2,7 раза більшим (1,96 ± 0,26 та 0,71 ± 0,08 відповідно, р &lt; 0,001). Саме зниження загальної спектральної потужності ЕЕГ, α/δ-коефіцієнта та підвищення (δ + θ)/(α + β)-коефіцієнта є найбільш показовими та загрозливими ЕЕГ-ознаками з точки зору ризику симптомного інсульту в пацієнтів із мНІМ.

Aperiodic measures of neural excitability are associated with anticorrelated hemodynamic networks at rest: A combined EEG-fMRI study

The hallmark of resting EEG spectra are distinct rhythms emerging from a broadband, aperiodic background. This aperiodic neural signature accounts for most of total EEG power, although its significance and relation to functional neuroanatomy remains obscure. We hypothesized that aperiodic EEG reflects a significant metabolic expenditure and therefore might be associated with the default mode network while at rest. During eyes-open, resting-state recordings of simultaneous EEG-fMRI, we find that aperiodic and periodic components of EEG power are only minimally associated with activity in the default mode network. However, a whole-brain analysis identifies increases in aperiodic power correlated with hemodynamic activity in an auditory-salience-cerebellar network, and decreases in aperiodic power are correlated with hemodynamic activity in prefrontal regions. Desynchronization in residual alpha and beta power is associated with visual and sensorimotor hemodynamic activity, respectively. These findings suggest that resting-state EEG signals acquired in an fMRI scanner reflect a balance of top-down and bottom-up stimulus processing, even in the absence of an explicit task.

Sleep-disordered breathing and sleep macro- and micro-architecture in children with Down syndrome.

Children with Down syndrome (DS) are at increased risk of sleep-disordered breathing (SDB), which is associated with intermittent hypoxia and sleep disruption affecting daytime functioning. We aimed to compare the impact of SDB on sleep quality in children with DS compared to typically developing (TD) children with and without SDB. Children with DS and SDB (n = 44) were age- and sex-matched with TD children without SDB (TD-) and also for SDB severity with TD children with SDB (TD+). Children underwent overnight polysomnography with sleep macro- and micro-architecture assessed using electroencephalogram (EEG) spectral analysis, including slow-wave activity (SWA, an indicator of sleep propensity). Children with DS had greater hypoxic exposure, more respiratory events during REM sleep, higher total, delta, sigma, and beta EEG power in REM than TD+ children, despite the same overall frequency of obstructive events. Compared to TD- children, they also had more wake after sleep-onset and lower sigma power in N2 and N3. The DS group had reduced SWA, indicating reduced sleep drive, compared to both TD groups. Our findings suggest that SDB has a greater impact on sleep quality in children with DS compared to TD children. SDB in children with DS exacerbates disruption of sleep quality, compared to TD children. The prevalence of SDB is very high in children with DS; however, studies on the effects of SDB on sleep quality are limited in this population. Our findings suggest that SDB has a greater impact on sleep quality in children with DS compared to TD children, and should be screened for and treated as soon as possible.

Effects of Slaughter Positions on Catecholamine, Blood Biochemical and Electroencephalogram Changes in Cattle Restrained Using a Modified Mark IV Box.

Simple SummarySlaughter position plays a crucial role from an animal welfare perspective (fear due to novelty, discomfort, and pain), as it involves handling by workers and restraint methods at abattoirs. In ritual slaughter, it is obligatory to restrain the animal in a prescribed position (lateral or upright), and lateral recumbency in Halal slaughter takes minimum effort in well-equipped abattoirs with trained staff compared to less equipped abattoirs with less trained personnel or, worst of all, outside of abattoirs. Halal slaughter is a technique practiced around the world by Muslims. No studies have been reported comparing upright and lateral positions in Halal slaughter and their impact on cattle blood biochemistry and pain sensation. Therefore, this study was designed to evaluate responses in cattle subjected to upright and lateral slaughter positions on EEG and catecholamines. The results revealed that the two positions had different effects on brain activity and blood parameters.The proper slaughter positioning of animals is among the most crucial factors in animal welfare. The lateral position in Halal slaughter is a technique used around the world by Muslims, with a few practicing the upright position. The literature on the effects of slaughter in upright versus lateral positions on pain and stress is scarce. Thus, this study was designed to evaluate the effects of slaughter positions on blood biochemical parameters, plasma catecholamines, and electroencephalographic (EEG) responses. Twenty Brahman crossbred steers were subjected to slaughter in either lateral recumbency (LP) (n = 10) or an upright position (UP) (n = 10). There was a significant increase in adrenaline (p < 0.0001) and noradrenaline (p < 0.05) at T2 compared to T1 in the animals of both groups. A significant difference (p < 0.0001) was observed in the median frequency (MF) and total power (Ptot) of EEG, parameters for pain and stress, between the animals slaughtered in the upright and the lateral position. However, MF and delta waves were significantly higher (p < 0.05) after slaughter in the UP group than in the LP group. The results demonstrate a lesser amount of stress and pain responses among the LP group.

Unmitigated Surgical Castration in Calves of Different Ages: Electroencephalographic and Neurohormonal Findings.

Simple SummaryCastration is a painful procedure that is commonly performed on cattle without analgesia. Although castration is considered to be more painful in older calves, studies examining the effect of age on electrophysiological and neurohormonal responses to pain under the same experimental conditions are limited. There are several limitations to providing pain mitigation for castration, one being the lack of available approved analgesics for use in alleviating the pain associated with castration in the United States. It is necessary to validate methods of pain assessment in cattle to support the development of pain relief drugs. The aim of this study was to investigate the effect of unmitigated surgical castration on the electroencephalography (EEG) responses and plasma substance P (SP) concentrations in calves, without pain relief across different age groups. Age, time, and procedure (castration or a simulated castration) impacted outcomes. The findings suggest that surgical castration without pain relief causes variations in EEG responses and in SP concentrations and that these responses are age related.Castration is a common management procedure employed in North American cattle production and is known to cause a pain response. The present study was designed to investigate the effect of unmitigated surgical castration on the electroencephalography (EEG) responses and plasma substance P (SP) concentrations in calves of different ages under the same experimental conditions. Thirty male Holstein calves in three age categories [<6 weeks (6W); 3 months (3M); 6 months (6M); 10 calves per age group] were used in the study. Calves were subjected to a simulated castration session (SHAM) followed 24 h later by surgical castration (CAST) without analgesia. An EEG analysis was performed before the procedure (i.e., baseline), at treatment, and 0–5, 5–10, and 10–20 min post-treatment for both SHAM and CAST, respectively. Blood samples were collected immediately prior to both treatments (time 0) and again at 1, 2, 4, 8, and 12 h after both treatments. The EEG results showed a three-way interaction between treatment, age, and time for delta and beta absolute power, beta relative power, total power, and median frequency (p = 0.004, p = 0.04, p = 0.04, p = 0.03, and p = 0.008, respectively). Following CAST, EEG total power decreased, and median frequency increased relative to SHAM in 6W and 3M calves only following treatment. For 6W and 3M calves, delta and beta absolute power increased at CAST and at later time points relative to SHAM. Marginal evidence for two-way interactions was noted between time and treatment and between age and treatment on the concentration of SP (p = 0.068 and p = 0.066, respectively). Substance P concentrations decreased in CAST treatment compared to SHAM at the later times (8 h: p = 0.007; 12 h: p = 0.048); 6W calves showed lower SP concentration at CAST relative to SHAM (p = 0.017). These findings indicate variation in EEG responses and in SP concentrations following unmitigated surgical castration in calves and that these responses may be age specific. These EEG findings have implications for supporting the perception of the pain associated with surgical castration in young calves and emphasize the urgency of pain mitigation strategies during routine husbandry practices such as castration, as typically implemented in North American cattle management.

Update on the SedLine® algorithm for calculating the Patient State Index of older individuals during general anesthesia: a randomized controlled trial.

The SedLine® sensor processes (Masimo Corporation; Irvine, CA, USA) raw electroencephalogram (EEG) signals and displays the depth of sedation as a Patient State Index (PSi). Reliance on standard processed EEG data and failure to recognize age-related effects can lead to an erroneous interpretation that low-amplitude EEG findings in an older patient signify an insufficient depth of anesthesia presented as abnormally high PSi values (AHPSi). We hypothesized that the incidence of AHPSi would decrease with the use of the recently-updated version of the SedLine® sensor, in which the Bispectral Index (BIS) values were used to titrate anesthesia. Thirty-three patients undergoing sevoflurane-remifentanil anesthesia were randomized into two groups. SedLine® sensors designed based on an old (v.1203) or updated (v.2000) algorithms were used. The BIS (v.4.1) and absolute index of total EEG power (TP) were simultaneously recorded. The attending anesthesiologists titrated the anesthetics, and BIS was maintained at 40-60. The incidence of AHPSi (PSi>50 with BIS 40-60) was calculated during the first 30 min after the start of surgery. Compared to the old algorithm group, the incidence of AHPSi was significantly lower in the updated algorithm group (26.7% vs. 4.2%, P<0.001). Lower TP values and the use of the old algorithm have significant effect on increased PSi values (P<0.001). The incidence of AHPSi decreased with the use of the updated version of the SedLine® algorithm.

EEG spectral changes induced by hemodialysis

ObjectiveTo investigate the EEG spectral changes induced during hemodialysis in patients with chronic kidney disease (CKD), and to identify the risk factors associated with changes in the Central Nervous System (CNS) during hemodialysis. Paradoxical neurological deterioration at the end of hemodialysis sessions, known as dialysis disequilibrium syndrome (DDS) has been described, but previous studies on EEG spectral changes during hemodialysis were controversial. MethodsWe performed quantitative EEG spectral analysis in 56 consecutive patients who underwent hemodialysis. We compared EEG at the start and at the end of the hemodialysis, and we correlated the spectral changes with the biochemical and clinical characteristics of the patients, using multivariate analysis. ResultsAt the end of hemodialysis sessions, we found a significant increase in total EEG power, relative power in delta frequency band and the ratio of delta-theta/alpha–beta power. EEG spectral changes were associated with younger age, recent start of hemodialysis therapy, level of uremia and lower level of glycaemia. ConclusionsQuantitative EEG spectral analysis showed that hemodialysis induced slowing of the EEG background activity. These changes were associated with risk factors of DDS. SignificanceEEG spectral changes are potential biomarkers for monitoring CNS function during hemodialysis.

ПСИХОФИЗИОЛОГИЧЕСКИЕ ПРЕДИКТОРЫ ВОЕННО-ПРОФЕССИОНАЛЬНОЙ АДАПТАЦИИ КУРСАНТОВ ПЕРВОГО КУРСА ВОЕННО-МОРСКОГО ИНСТИТУТА

There are no sufficient up-to-date publications on psychophysiological determinants of military-occupational adaptation and interrelations between psychological and psychophysiological characteristics of cognitive and personal spheres in first-year cadets of a naval institute. The aim of our research is to study the correlation between external criteria of military-occupation adaptation, cognitive functions and mental characteristics of cadets of the first-year of a naval institute, on the one hand, and their bioelectrical activity of the brain cortex, characteristics of the cardiovascular system, on the other hand, which can be used as predictors of military-occupational adaptation. The object were first-year cadets of the Naval institute (n = 125). We used physiological methods of investigation of mental properties of a person, motivation, emotional state, cognitive functions and intelligence, methods of electroencephalography and the analysis of heart rate variability, finger photoplethysmography. The relationship between investigated parameters were studied with the help of the correlation and multiple regression analysis, exploratory and confirmatory factor analysis. Strengthening of total spectral power of EEG at the rest state with closed eyes, especially of α-rhythm power, powerful vascular tone and heart rate variability correlated with high level of military-occupational adaptation. Spectral power decrease of δ-2-rhythm in left central lead, vascular tone decrease, worsening of ability to spatial figurative representations, increasing of aggression and neuroticism accompanied by the deterioration level of health of cadets and derangement of adaptable mechanisms. We have defined psychophysiological parameters which are predictors of military-occupational adaptation.

Wireless ‘under the skull’ epidural EEG and behavior in piglets during nitrous oxide or carbon dioxide gas euthanasia

Consciousness is central to animal welfare concerns. Its assessment is most often conducted based on behavior, with a poor understanding of the correspondence between behavior and the neurobiological processes that underlie the subjective experience of consciousness. Recording of brain electrical activity using electrodes placed under the skull improves EEG recording by minimizing artifacts from muscular or cardiac activities, and it can now be combined with wireless recording in free-moving animals. This experiment investigated the correspondence between wireless ‘under the skull’ epidural EEG and the behavior of 18 five-week-old female piglets undergoing nitrous oxide (N2O) or carbon dioxide (CO2) gradual fill gas euthanasia at 25% replacement rate per minute of the chamber volume. Piglets exposed to CO2 had a peak in EEG total power (‘Ptot’) during the flailing stage, whereas piglets exposed to N2O had a higher EEG 95% spectral edge frequency (‘F95’) during their initial explorative behavior phase and a drop in EEG median frequency (‘F50’) after loss of posture. Loss of posture without righting attempt, as the last behavioral state observed during euthanasia, preceded the onset of transitional EEG on average by 0.9 and 3.1 min (for CO2 and N2O treatments, respectively), and the onset of isoelectric EEG by 4.5 and 6.2 min (for CO2 and N2O treatments, respectively). Paddling movements occurred shortly before and during transitional EEG but never during isoelectric EEG, whereas gasps persisted after the EEG had become isoelectric. The dynamics of EEG spectral changes were complex to interpret in relation to the degree of consciousness, but isoelectric EEG as an unequivocal indicator of unconsciousness appeared several minutes after loss of posture with no righting attempt. This leaves a window of uncertainty in regards to the potential for consciousness after loss of posture during gradual fill gas euthanasia in piglets.

Cohort study of electroencephalography markers of amyloid-tau-neurodegeneration pathology.

Electroencephalography signatures of amyloid-β, tau and neurodegenerative pathologies would aid in screening for, tracking progression of, and critically, understanding the pathogenesis of dementia. We hypothesized that slowing of the alpha peak frequency, as a signature of hyperpolarization-activated cyclic nucleotide gated ‘pacemaker’ channel activity, would correlate with amyloid and tau pathology burden measured by amyloid (Pittsburgh Compound B) and tau (MK-6240) positron emission tomography or CSF biomarkers. We also hypothesized that EEG power would be associated with neurodegeneration (CSF neurofilament light and hippocampal volume). Wakeful high-density EEG data were collected from 53 subjects. Both amyloid-β and tau pathology were associated with slowing in the alpha peak frequency [Pittsburgh Compound B (+) vs. Pittsburgh Compound B (−) subjects, P = 0.039 and MK-6240 (+) vs. MK-6240 (−) subjects, P = 0.019]. Furthermore, slowing in the peak alpha frequency correlated with CSF Aβ42/40 ratio (r2 = 0.270; P = 0.003), phosphoTau (pTau181, r2 = 0.290; P = 0.001) and pTau181/Aβ42 (r2 = 0.343; P < 0.001). Alpha peak frequency was not associated with neurodegeneration. Higher CSF neurofilament light was associated with lower total EEG power (r2 = 0.136; P = 0.018), theta power (r2 = 0.148; P = 0.014) and beta power (r2 = 0.216; P = 0.002); the latter was also associated with normalized hippocampal volume (r2 = 0.196; P = 0.002). Amyloid-tau and neurodegenerative pathologies are associated with distinct electrophysiological signatures that may be useful as mechanistic tools and diagnostic/treatment effect biomarkers in clinical trials.