Electroencephalogram Spectral Power Research Articles

Difference in spectral power density of sleep electroencephalography in individuals with or without insomnia

Introduction Power spectral analysis is the most common method of quantitative electroencephalogram (qEEG) techniques and enables investigation of the microstructure of insomnia. Previous spectral analysis studies on insomnia have shown inconsistent results due to their heterogeneity and small sample sizes.ObjectivesWe compared the difference of electroencephalogram (EEG) spectral power during sleep among participants without insomnia, insomniacs with no hypnotic use, hypnotic users with no insomnia complaints, and hypnotic users with insomnia complaints.MethodsWe used the Sleep Heart Health Study data, which is large sample size and has good quality control. The fast Fourier transformation was used to calculate the EEG power spectrum for total sleep duration within contiguous 30-second epochs of sleep. For 1,985 participants, EEG spectral power was compared among the groups while adjusting for potential confounding factors that could affect sleep EEG.ResultsThe power spectra during total sleep differed significantly among the groups in all frequency bands (p corr < 0.001). We found that quantitative EEG spectral power in the beta and sigma bands of total sleep differed (p corr < 0.001) between participants without insomnia and hypnotic users with insomnia complaints after controlling for potential confounders. The higher beta and sigma power were found in the hypnotic users with insomnia complaints than in the non-insomnia participants.ConclusionsThis study suggests differences in the microstructures of polysomnography-derived sleep EEG between the insomnia groups.DisclosureNo significant relationships.

Difference in spectral power density of sleep electroencephalography between individuals without insomnia and frequent hypnotic users with insomnia complaints

Previous spectral analysis studies on insomnia have shown inconsistent results due to their heterogeneity and small sample sizes. We compared the difference of electroencephalogram (EEG) spectral power during sleep among participants without insomnia, insomniacs with no hypnotic use, hypnotic users with no insomnia complaints, and hypnotic users with insomnia complaints using the Sleep Heart Health Study data, which is large sample size and has good quality control. The fast Fourier transformation was used to calculate the EEG power spectrum for total sleep duration within contiguous 30-s epochs of sleep. For 1985 participants, EEG spectral power was compared among the groups while adjusting for potential confounding factors that could affect sleep EEG. The power spectra during total sleep differed significantly among the groups in all frequency bands (pcorr < 0.001). We found that quantitative EEG spectral power in the beta and sigma bands of total sleep differed (pcorr < 0.001) between participants without insomnia and hypnotic users with insomnia complaints after controlling for potential confounders. The higher beta and sigma power were found in the hypnotic users with insomnia complaints than in the non-insomnia participants. This study suggests differences in the microstructures of polysomnography-derived sleep EEG between the two groups.

Differential effects of the novel neurosteroid hypnotic (3β,5β,17β)-3-hydroxyandrostane-17-carbonitrile on electroencephalogram activity in male and female rats

BackgroundWe recently showed that a neurosteroid analogue, (3β,5β,17β)-3-hydroxyandrostane-17-carbonitrile (3β-OH), induced hypnosis in rats. The aim of the present study was to evaluate the hypnotic and anaesthetic potential of 3β-OH further using electroencephalography. MethodsWe used behavioural assessment and cortical electroencephalogram (EEG) spectral power analysis to examine hypnotic and anaesthetic effects of 3β-OH (30 and 60 mg kg−1) administered intraperitoneally or intravenously to young adult male and female rats. ResultsWe found dose-dependent sex differences in 3β-OH-induced hypnosis and EEG changes. Both male and female rats responded similarly to i.p. 3β-OH 30 mg kg−1. However, at the higher dose (60 mg kg−1, i.p.), female rats had two-fold longer duration of spontaneous immobility than male rats (203.4 [61.6] min vs 101.3 [32.1] min), and their EEG was suppressed in the low-frequency range (2–6 Hz), in contrast to male rats. Although a sex-dependent hypnotic effect was not confirmed after 30 mg kg−1 i.v., female rats appeared more sensitive to 3β-OH with relatively small changes within delta (1–4 Hz) and alpha (8–13 Hz) bands. Finally, 3β-OH had a rapid onset of action and potent hypnotic/anaesthetic effect after 60 mg kg−1 i.v. in rats of both sexes; however, all female rats and only half of the male rats reached burst suppression, an EEG pattern usually associated with profound inhibition of thalamocortical networks. ConclusionsBased on its behavioural effects and EEG signature, 3β-OH is a potent hypnotic in rats, with female rats being more sensitive than male rats.

Noise amplification precedes extreme epileptic events on human EEG.

Extreme events are rare and sudden abnormal deviations of the system's behavior from a typical state. Statistical analysis reveals that if the time series contains extreme events, its distribution has a heavy tail. In dynamical systems, extreme events often occur due to developing instability preceded by noise amplification. Here, we apply this theory to analyze generalized epileptic seizures in the human brain. First, we demonstrate that the time series of electroencephalogram (EEG) spectral power in a frequency band of 1-5Hz obeys a heavy-tailed distribution, confirming the presence of extreme events. Second, we report that noise on EEG signals gradually increases before the seizure onset. Thus, we hypothesize that generalized epileptic seizures in humans are the extreme events emerging from instability accompanied by preictal noise amplification similar to other dynamical systems.

Hippocampal and medial prefrontal cortical volume is associated with overnight declarative memory consolidation independent of specific sleep oscillations.

The current study was designed to further clarify the influence of brain morphology, sleep oscillatory activity and age on memory consolidation. Specifically, we hypothesized, that a smaller volume of hippocampus, parahippocampal and medial prefrontal cortex negatively impacts declarative, but not procedural, memory consolidation. Explorative analyses were conducted to demonstrate whether a decrease in slow-wave activity negatively impacts declarative memory consolidation, and whether these factors mediate age effects on memory consolidation. Thirty-eight healthy participants underwent an acquisition session in the evening and a retrieval session in the morning after night-time sleep with polysomnographic monitoring. Declarative memory was assessed with the paired-associate word list task, while procedural memory was tested using the mirror-tracing task. All participants underwent high-resolution magnetic resonance imaging. Participants with smaller hippocampal, parahippocampal and medial prefrontal cortex volumes displayed a reduced overnight declarative, but not procedural memory consolidation. Mediation analyses showed significant age effects on overnight declarative memory consolidation, but no significant mediation effects of brain morphology on this association. Further mediation analyses showed that the effects of age and brain morphology on overnight declarative memory consolidation were not mediated by polysomnographic variables or sleep electroencephalogram spectral power variables. Thus, the results suggest that the association between age, specific brain area volume and overnight memory consolidation is highly relevant, but does not necessarily depend on slow-wave sleep as previously conceptualized.

An attempt to identify reproducible high-density EEG markers of PTSD during sleep.

We examined electroencephalogram (EEG) spectral power to study abnormalities in regional brain activity in post-traumatic stress disorder (PTSD) during sleep. We aimed to identify sleep EEG markers of PTSD that were reproducible across nights and subsamples of our study population. Seventy-eight combat-exposed veteran men with (n = 31) and without (n = 47) PTSD completed two consecutive nights of high-density EEG recordings in a laboratory. We performed spectral-topographical EEG analyses on data from both nights. To assess reproducibility, we used the first 47 consecutive participants (18 with PTSD) for initial discovery and the remaining 31 participants (13 with PTSD) for replication. In the discovery analysis, compared with non-PTSD participants, PTSD participants exhibited (1) reduced delta power (1-4 Hz) in the centro-parietal regions during nonrapid eye movement (NREM) sleep and (2) elevated high-frequency power, most prominent in the gamma band (30-40 Hz), in the antero-frontal regions during both NREM and rapid eye movement (REM) sleep. These findings were consistent across the two study nights, with reproducible trends in the replication analysis. We found no significant group differences in theta power (4-8 Hz) during REM sleep and sigma power (12-15 Hz) during N2 sleep. The reduced centro-parietal NREM delta power, indicating reduced sleep depth, and the elevated antero-frontal NREM and REM gamma powers, indicating heightened central arousal, are potential objective sleep markers of PTSD. If independently validated, these putative EEG markers may offer new targets for the development of sleep-specific PTSD diagnostics and interventions.

Investigating the Relationship Between Eye Movement and Brain Wave Activity Using Video Games: Pilot Study.

BackgroundAll eye movements are related in one way or another to our mental processes with lateral eye movements being associated with the different hemispheres of the brain. Eye movement techniques form the basis of eye movement desensitization and reprocessing therapy, wherein forced eye movements activate neurological pathways to treat the subject.ObjectiveThe objective of our study was to examine the relationship between players' eye movements and their brain wave activities using a video game.MethodsWe used similar eye movement techniques in the form of a video game called Lifeguard that could potentially stimulate different eye movement mode and create a more engaging experience for the user. By designing an experiment, we further explored the differences in electroencephalogram spectral power activity for the alpha, beta, theta, delta, and gamma frequency bands in Lifeguard and Tetris.ResultsThe game based on eye movement technologies resulted in decreased delta power and increased beta power, but significant difference between 2 games was not found.ConclusionsThe applied uses of this research could mean that eye movement desensitization and reprocessing can be conducted in a more fun and engaging way through the use of gaming technology.

Detection of electroencephalographic, electromyographic, and cardiac variations during wake-sleep transition through change point analysis

Introduction. Wake-sleep transition is a continuous, gradual process of change. Most studies evaluating electroencephalogram spectral power during this transition have used variance analysis (ANOVA). However, using this type of analysis does not allow one to detect specific changes in the statistical properties of a time series. Objective. To determine whether change point analysis (CPA) makes it possible to identify and characterize electroencephalographic, electromyographic, and cardiac changes during the wake-sleep transition through a cross-sectional study. Method. The study included 18 healthy volunteers (12 women and six men), from which polysomnography data were obtained during a two-minute transition. Heart rate, respiratory sinus arrhythmia, electroencephalogram spectral power, as well as electromyographic median and mean frequency and electromyographic root mean square were calculated in five-second segments. These segments were analyzed using repeated measures ANOVA, and CPA focused individually and for the group as a whole. Results. Repeated measures ANOVA and CPA by group found decreased levels of alpha and beta power and beta/delta index during wakefulness, and increased theta and delta power levels during sleep. CPA by individual found that only alpha power changed in all participants and failed to identify a specific moment when all the variables studied changed simultaneously. Discussion and conclusion. We consider that CPA provides additional information to statistical analyses such as ANOVA for the specific location of physiological changes during sleep-wake transition.

Quantitative electroencephalographic changes in children with autism spectrum disorders

Background Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders characterized by impairment of social interaction, communication, and behavior. It has been recently suggested that ASD are characterized by abnormal brain networks and connectivity, which was studied using neuroimaging modalities. Objective The aim of this study is to assess the quantitative electroencephalographic (QEEG) findings in children with ASD compared with age-matched children and to assess if QEEG analysis is a sensitive and simple method to aid in the diagnosis of ASD in children. Patients and methods QEEG recordings of 50 children with ASD between the ages of 2 and 6 years were compared with those of 50 age-matched controls under eyes-closed condition. Brain functioning and its connectivity were examined using measurements of spectral analysis of both absolute and relative power and interhemispheric coherence. Results There were statistically significant differences in electroencephalogram spectral power and coherence between the study and control groups. It revealed an increased absolute delta power in the frontal, anterior temporal, midtemporal, central, and parietal regions and an increase of absolute alpha power mainly in the prefrontal and frontal regions. There was a greater beta power in midtemporal and posterior temporal regions. In addition, interhemispheric coherence showed a pattern of frontal overconnectivity and temporal underconnectivity with the other brain areas in children with ASD in comparison with the control group. Moreover, statistical differences in electroencephalogram spectral power and coherence between the different grades of children with ASD were noticed. Conclusion These results suggested that children with ASD have QEEG dysfunctions that underlie their symptomatology. Hence, QEEG provides a useful method that aids in the diagnosis of children with ASD.

Relationships of Alpha, Beta, and Theta EEG Spectra Properties with Aggressive and Nonaggressive Antisocial Behavior in Children and Adolescents

Abstract We investigated potential correlations between underlying electroencephalogram (EEG) spectral power and aggressive or nonaggressive antisocial behavior. Frontal and parietal EEG spectral properties were calculated for 3 different ranges (theta, 4–8 Hz; alpha, 8–10.5 Hz; and beta, 10.5–30 Hz) in 900 twins in an open-eyed resting state during 2 stages of development: ages 9–10 and ages 14–15. In multilevel regression modeling, relationships emerged between EEG spectral power properties and measures of antisocial behavior at age 14–15 years but not at the concurrent age of 9–10 years, providing support for neurodevelopmental underpinnings for adolescent-onset antisocial behavior. For boys, frontal alpha power, frontal beta power, and parietal beta power were correlated with aggressive antisocial behavior. For girls, parietal alpha power was anticorrelated with nonaggressive antisocial behavior, raising questions about differing neurobiological profiles for antisocial behavior between sexes. These results also support a distinction between aggressive and nonaggressive antisocial behavior.

EEG Spectral Generators Involved in Motor Imagery: A swLORETA Study.

In order to characterize the neural generators of the brain oscillations related to motor imagery (MI), we investigated the cortical, subcortical, and cerebellar localizations of their respective electroencephalogram (EEG) spectral power and phase locking modulations. The MI task consisted in throwing a ball with the dominant upper limb while in a standing posture, within an ecological virtual reality (VR) environment (tennis court). The MI was triggered by the visual cues common to the control condition, during which the participant remained mentally passive. As previously developed, our paradigm considers the confounding problem that the reference condition allows two complementary analyses: one which uses the baseline before the occurrence of the visual cues in the MI and control resting conditions respectively; and the other which compares the analog periods between the MI and the control resting-state conditions. We demonstrate that MI activates specific, complex brain networks for the power and phase modulations of the EEG oscillations. An early (225 ms) delta phase-locking related to MI was generated in the thalamus and cerebellum and was followed (480 ms) by phase-locking in theta and alpha oscillations, generated in specific cortical areas and the cerebellum. Phase-locking preceded the power modulations (mainly alpha–beta ERD), whose cortical generators were situated in the frontal BA45, BA11, BA10, central BA6, lateral BA13, and posterior cortex BA2. Cerebellar-thalamic involvement through phase-locking is discussed as an underlying mechanism for recruiting at later stages the cortical areas involved in a cognitive role during MI.

Automated selective disruption of slow wave sleep

BackgroundSlow wave sleep (SWS) plays an important role in neurophysiologic restoration. Experimentally testing the effect of SWS disruption previously required highly time-intensive and subjective methods. Our goal was to develop an automated and objective protocol to reduce SWS without affecting sleep architecture. New methodWe developed a custom Matlab™ protocol to calculate electroencephalogram spectral power every 10s live during a polysomnogram, exclude artifact, and, if measurements met criteria for SWS, deliver increasingly louder tones through earphones. Middle-aged healthy volunteers (n=10) each underwent 2 polysomnograms, one with the SWS disruption protocol and one with sham condition. ResultsThe SWS disruption protocol reduced SWS compared to sham condition, as measured by spectral power in the delta (0.5–4Hz) band, particularly in the 0.5–2Hz range (mean 20% decrease). A compensatory increase in the proportion of total spectral power in the theta (4–8Hz) and alpha (8–12Hz) bands was seen, but otherwise normal sleep features were preserved. N3 sleep decreased from 20±34 to 3±6min, otherwise there were no significant changes in total sleep time, sleep efficiency, or other macrostructural sleep characteristics. Comparison with existing methodThis novel SWS disruption protocol produces specific reductions in delta band power similar to existing methods, but has the advantage of being automated, such that SWS disruption can be performed easily in a highly standardized and operator-independent manner. ConclusionThis automated SWS disruption protocol effectively reduces SWS without impacting overall sleep architecture.

Acupuncture for Pain in Chronic Pancreatitis: A Single-Blinded Randomized Crossover Trial.

Many patients with painful chronic pancreatitis (CP) have insufficient effect of treatment, and the prevalence of adverse effects is high. Consequently, alternatives to conventional management are needed. We aimed to study the effect of acupuncture in painful CP. This was a prospective, single-blinded, randomized crossover trial. Fifteen patients with CP were assigned to a session of acupuncture followed by sham stimulation or vice versa. Patients rated clinical pain scores daily on a 0 to 10 visual analogue scale (VAS) and completed the Patient Global Impression of Change. For mechanistic linkage, resting state electroencephalograms were recorded and quantified by spectral power analysis to explore effects on central pain processing. Acupuncture, compared with sham stimulation, caused more pain relief (2.0 ± 1.5 VAS vs 0.7 ± 0.8 VAS; P = 0.009). The effect, however, was short, and after 1-week follow-up, there was no difference in clinical pain scores between groups (P = 1.0) or the rating of Patient Global Impression of Change (P = 0.8). Electroencephalogram spectral power distributions between sham and acupuncture were comparable between groups (all P > 0.6). The study presents proof-of-concept for the analgesic effect of acupuncture in pancreatic pain. Although the effect was short lasting, the framework may be used to conceptualize future trials of acupuncture in visceral pain.

THE EFFECT OF MILD COGNITIVE IMPAIRMENT ON EEG TOPOGRAPHIC CHANGES AFTER ON-PUMP CORONARY ARTERY BYPASS GRAFTING

The purpose . Previously it was shown that on-pump coronary artery bypass grafting (CABG) induced cerebral ischemia and cognitive decline. The patients with mild cognitive impairment (MCI) could be a high-risk group of CABG-associated cognitive decline. Non-invasive neuromonitoring can provide information regarding subclinical symptoms and topography of cerebral ischemia. The aim of this study was to investigate the topographic changes in electroencephalogram (EEG) spectral power in coronary artery disease (CAD) patients with or without MCI before and after on-pump CABG. Methods : 62 males with CAD were divided into two groups according to their Mini-Mental State Examination: without MCI (n = 37) and with MCI (n = 25). Clinical factors were assessed, including the severity of coronary lesions (SYNTAX score), the left ventricular ejection fraction (LVEF). Eyes-closed rest EEG was recorded from 62 channels positioned according to the International 10–20 system. Spectral EEG power was calculated for frequencies from 0.1 to 50 Hz. Results : The patients with MCI had theta-1 (4–6 Hz) power increase 7-10 days after on-pump CABG only in frontal and fronto-central clusters of right and left hemispheres as compared to the preoperative values, whereas in the groups without MCI this effect was widespread over the brain. In the beta-1 band (13–20 Hz), CABG patients with MCI had power increase in the frontal, fronto-central and fronto-temporal regions of the brain cortex. Similar power changes in patients without MCI were observed only for occipital brain clusters. Conclusions : CAD patients with MCI have demonstrated EEG signs of cortical dysfunction focused on the frontal brain areas. Cortical dysfunction in this localization can be associated with the progression of cognitive deficits, causing loss social integration in CAD patients with MCI.

Age at first cannabis use moderates EEG markers of recovery from cannabis

Background and Aims: Cannabis-induced cerebral perfusion deficits cause reduced electroencephalogram spectral power. In previous work, spectral power did not recover with cannabis abstinence. This study uses EEG to explore moderators of recovery during cannabis abstinence.Methods: A within-subject prospective community-based cannabis abstinence study was conducted with 10 cannabis-dependent participants. Resting EEG was measured before and after 14 days of abstinence at frontal and occipital electrodes. Demographic, drug use and withdrawal data were explored as moderators of EEG recovery.Results: In adjusted models, age at first cannabis use predicted EEG power change in the beta/gamma frequency band at frontal electrodes, as did participant age.Conclusion: Age at first cannabis use may moderate increases in EEG beta/gamma band power with cannabis abstinence.

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

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 1Hz step revealed by measuring the interval durations between points crossing zero (isoline) by a curve. EEG spectral power changes were analyzed for delta (1.5–4Hz), theta (4–7.5Hz), alpha-1 (7.5–9.5Hz), alpha-2 (9.5–12.5Hz), beta-1 (12.5–18Hz) and beta-2 (18–30Hz) 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.

Individual differences in physiologic measures are stable across repeated exposures to total sleep deprivation.

Some individuals show severe cognitive impairment when sleep deprived, whereas others are able to maintain a high level of performance. Such differences are stable and trait‐like, but it is not clear whether these findings generalize to physiologic responses to sleep loss. Here, we analyzed individual differences in behavioral and physiologic measures in healthy ethnic‐Chinese male volunteers (n = 12; aged 22–30 years) who were kept awake for at least 26 h in a controlled laboratory environment on two separate occasions. Every 2 h, sustained attention performance was assessed using a 10‐min psychomotor vigilance task (PVT), and sleepiness was estimated objectively by determining percentage eyelid closure over the pupil over time (PERCLOS) and blink rate. Between‐subject differences in heart rate and its variability, and electroencephalogram (EEG) spectral power were also analyzed during each PVT. To assess stability of individual differences, intraclass correlation coefficients (ICC) were determined using variance components analysis. Consistent with previous work, individual differences in PVT performance were reproducible across study visits, as were baseline sleep measures prior to sleep deprivation. In addition, stable individual differences were observed during sleep deprivation for PERCLOS, blink rate, heart rate and its variability, and EEG spectral power in the alpha frequency band, even after adjusting for baseline differences in these measures (range, ICC = 0.67–0.91). These findings establish that changes in ocular, ECG, and EEG signals are highly reproducible across a night of sleep deprivation, hence raising the possibility that, similar to behavioral measures, physiologic responses to sleep loss are trait‐like.

Brain oscillatory activity during sleep shows unknown dysfunctions in early encephalopathy.

Electroencephalographic recordings in cirrhotic patients without overt hepatic encephalopathy (HE) have mainly been performed during wakefulness. Our aim was to quantify their alterations in nocturnal sleep electroencephalogram (EEG). In 20 patients and 20 healthy volunteers, we recorded a nocturnal digital polysomnography. Different sleep parameters were measured. Besides, we performed quantitative analysis of EEG (qEEG) as follows: spectral power in the different sleep stages was calculated in the frequency bands low δ, δ, θ, α, and σ. Also, the mean dominant frequency and Sleep Indexes were obtained. In comparison with controls, the group of patients showed (1) different alterations in both the microstructure and the macrostructure of sleep; (2) an increase in, both, θ band power and the average mean dominant frequency during rapid eye movement (REM); (3) in all sleep stages, a decrease of sleep electroencephalogram spectral power in low δ band and an increase in δ band: and (4) in stages N3 and REM, significant increases in the minimum of mean dominant frequency and in the respective sleep indexes. Therefore, in cirrhotic patients without overt HE, and likely having minimal hepatic encephalopathy, we found different alterations in both the microstructure and the macrostructure of nocturnal sleep. Also, sleep qEEG showed a brain dysfunction in slow oscillatory mechanisms intrinsic of sleep stages, with an increase in the frequency of its maximal electroencephalogram synchronization, from low δ to δ band. These alterations may reflect the onset of encephalopathy; sleep qEEG may, thus, be an adequate tool for its brain functional evaluation and follow-up.

Theta frequency activity during rapid eye movement (REM) sleep is greater in people with resilience versus PTSD

Emotional memory consolidation has been associated with rapid eye movement (REM) sleep, and recent evidence suggests that increased electroencephalogram spectral power in the theta (4-8Hz) frequency range indexes this activity. REM sleep has been implicated in posttraumatic stress disorder (PTSD) as well as in emotional adaption. In this cross-sectional study, thirty young healthy African American adults with trauma exposure were assessed for PTSD status using the Clinician Administered PTSD Scale. Two consecutive night polysomnographic (PSG) recordings were performed and data scored for sleep stages. Quantitative electroencephalographic spectral analysis was used to measure theta frequency components sampled from REM sleep periods of the second-night PSG recordings. Our objective was to compare relative theta power between trauma-exposed participants who were either resilient or haddeveloped PTSD. Results indicated higher right prefrontal theta power during the first and last REM periods in resilient participants compared with participants with PTSD. Right hemisphere prefrontal theta power during REM sleep may serve as a biomarker of the capacity for adaptive emotional memory processing among trauma-exposed individuals.

Mild cognitive impairment in patients with coronary artery disease: clinical-demographyc and EEG-correlates

The clinical and demographic factors associated with mild cognitive impairment (MCI) and the topographical features of electroencephalogram (EEG) spectral power in patients with coronary artery disease (CAD) depending on the presence or absence of MCI were studied. Seventy-five male patients with CAD were assigned to the groups with (n=31) and without MCI (n=44). The control group included 15 healthy people (the mean age 60.0 ± 4.39 years). The MMSE, the Frontal Assessment battery, the Trail-Making Test, Khanin-Speilberger and Beck depression scales were used. A lower level of education, more severe coronary lesions and lower cardiac contractility, as well as higher spectral power (Θ-rhythm) of parietooccipital theta activity have been found in CAD patients with MCI compared to patients without MCI. The latter parameter in MCI patients also differed from controls. Education is an important factor to preserve cognitive abilities in patients with CAD. In addition, the severity of coronary artery lesions and low cardiac contractility affect the degree of cerebral ischemia and neuronal dysfunction detected by spectral EEG power. The efficacy of quantitative EEG analysis methods for early detection and prevention of cognitive disorders in CAD patients was confirmed.