EEG Theta Power Research Articles

Error Induction to Improve Performance with Increased EEG Theta Power for a Motor Rehabilitation Task

Error Induction to Improve Performance with Increased EEG Theta Power for a Motor Rehabilitation Task

Elevated correlations in cardiac–neural dynamics: An impact of mantra meditation on stress alleviation

Mantra meditation is a widely practiced technique with a demonstrated ability to promote relaxation and alleviate stress. This study aims to evaluate the impact of regular mantra meditation practice on electroencephalogram (EEG) patterns and heart rate variability (HRV) in young adults grappling with increased stress levels. Furthermore, the study explored possible correlations between these two physiological markers. Thirty-eight participants practiced mantra meditation for eight weeks, and their EEG and HRV were recorded before and after. The pre-post analysis evaluated brain activity and autonomic nervous system regulation alterations by examining EEG and HRV in the time, frequency, and nonlinear domains. Data analysis revealed significant correlations between EEG patterns and HRV indices following mantra meditation, suggesting a potential interconnection between neural and cardiovascular regulation. A notable increase in Root Mean Square of Successive Differences (RMSSD) and Standard Deviation of NN intervals (SDNN) within HRV, along with a decrease in Heart Rate (HR) and Stress Index (SI) and an increase in EEG alpha and theta power, accompanied by a reduction in their ratio, was observed. Three pivotal correlations consistently increased during eight weeks: Alpha/Theta Ratio (ATR) with Low-Frequency/High-Frequency Ratio (LHR), ATR with SD2/SD1 Ratio (SDR), and Relaxation Index (RI) with Stress Index (SI). After eight weeks, these correlations attained statistical significance, optimizing the balance between calmness and vigilance, boosting parasympathetic activity, and reducing chaos between the parasympathetic and sympathetic systems. The study elucidates the scientific mechanisms of mantra meditation, enriching research on its stress-reducing effects and emphasizing mental and physical well-being.

Multimodal training on L2 Japanese pitch accent: learning outcomes, neural correlates and subjective assessments

Abstract Japanese pitch accent is phonemic, making it crucial for second-language learners to acquire. Building on theories of multimodal learning, the present study explored how auditory, visual and gestural training of Japanese pitch accent affected behavioral, neural and meta-cognitive aspects of pitch perception across two experiments. Experiment 1 used a between-subjects pre/posttest design to train native English speakers to perceive Japanese pitch accents in one of the following three conditions: (1) baseline (audio + flat notation), (2) pitch height notation (audio + notation mimicking pitch height) and (3) pitch height notation + a left-hand gesture (L-gesture) (to engage the contralateral right hemisphere specialized for suprasegmental pitch processing). Our results indicated that (2) pitch height notation training was most robust in its benefits, as participants in this condition improved on trained and novel words alike. Experiment 2 used a within-subjects design to extend Experiment 1 in three ways: adding a right-hand gesture (R-gesture) condition (to engage more segmental language areas in the left hemisphere), introducing a neural correlate of cognitive load (measured by EEG alpha and theta power) and performing a metacognitive subjective assessment of learning (e.g., ‘Which training did you find the most helpful?’). The results showed that although there were no differences among our four training conditions on learning outcomes or EEG power, participants made the most positive subjective evaluations about pitch height notation and R-gesture training. Together, the results suggest that there may be a ‘just right’ amount of multimodal instruction to boost learning and increase engagement during foreign language pitch instruction.

Inter-individual variability in neural response to low doses of LSD

The repeated use of small doses of psychedelics (also referred to as “microdosing”) to facilitate benefits in mental health, cognition, and mood is a trending practice. Placebo-controlled studies however have largely failed to demonstrate strong benefits, possibly because of large inter-individual response variability. The current study tested the hypothesis that effects of low doses of LSD on arousal, attention and memory depend on an individual’s cognitive state at baseline. Healthy participants (N = 53) were randomly assigned to receive repeated doses of LSD (15 mcg) or placebo on 4 occasions divided over 2 weeks. Each treatment condition also consisted of a baseline and a 1-week follow-up visit. Neurophysiological measures of arousal (resting state EEG), pre-attentive processing (auditory oddball task), and perceptual learning and memory (visual long-term potentiation (LTP) paradigm) were assessed at baseline, dosing session 1 and 4, and follow-up. LSD produced stimulatory effects as reflected by a reduction in resting state EEG delta, theta, and alpha power, and enhanced pre-attentive processing during the acute dosing sessions. LSD also blunted the induction of LTP on dosing session 4. Stimulatory effects of LSD were strongest in individuals with low arousal and attention at baseline, while inhibitory effects were strongest in high memory performers at baseline. Decrements in delta EEG power and enhanced pre-attentive processing in the LSD treatment condition were still present during the 1-week follow-up. The current study demonstrates across three cognitive domains, that acute responses to low doses of LSD depend on the baseline state and provides some support for LSD induced neuroadaptations that sustain beyond treatment.

Электофизиологические корреляты точности выстрела у лучников разной квалификации

The purpose of this study was to establish electrophysiological markers of archers’ shot accuracy by correlations between performance and electroencephalogram (EEG) power parameters in athletes of different ranks compared. Materials and methods. The research involved 20 archers shooting the classic bow, who were divided into two groups of 10 subjects each by sports rank: Candidate for Master of Sport and First-Class Sportsman. EEG was recorded using the Encephalan-EEGR-19/26 device (Medikom MTD, Taganrog) in 19 leads according to the 10–20 system. Reference electrodes were placed on the earlobes. Results. It was found that shot accuracy of high-level archers (Candidate for Master of Sport) is marked by an increase in alpha and theta EEG power in the occipito-temporal-frontal regions of the left hemisphere during the preparatory phases of the exercise, and then, by the dissociation of the powers of these frequency ranges while aiming. In contrast, shot accuracy of lower level archers is characterized by a decrease in the power of the main rhythm in the left temporal lead during the first phase of the shot. In the total sample of athletes (regardless of rank) no significant correlations were found in any of the 3365 cases of evaluation of this analytical parameter. Thus, the electrophysiological markers of bow shot accuracy differ between Candidates for Master of Sport and First-Class Sportsmen. The sevenfold greater number of significant correlations (p < 0.05) between EEG parameters and shot accuracy of Candidates for Master of Sport compared to First-Class Sportsmen indicates a high level of development of the Bow Shot functional system of purposeful movements as the skill improves, as well as testifies to the synergism of physiological processes when performing the exercise by Candidates for Master of Sport. The established facts will expand coaches’ physiological understanding of the mechanism of purposeful movements in order to objectively predict sports results.

Electroencephalogram monitoring during ketamine antidepressant treatment: a pilot study

Introduction Depression is a major cause of disability world-wide. Up to a third of patients have a treatment-resistant form (TRD), presenting a major challenge. Ketamine has been introduced as a novel rapid-acting antidepressant effective in this population. However, at present, ketamine treatment is not routinely informed by any objective neural markers. Basic research has shown promising electroencephalogram (EEG) changes including a decrease in alpha power. However, clinical translation is lacking.ObjectivesAssess the feasibility of identifying EEG correlates of ketamine infusions in a routine outpatient setting with a low-cost, easily usable system.MethodsThe study was carried out at the Oxford Health Foundation Trust Ketamine Clinic (ethics reference 22/EM/0226). N=18 EEG recordings from N=12 patients were collected (5 women, mean age 44, range 33-62, IV dose 0.5-1mg/kg over 40min). 4-channel EEG was collected with a Muse-S headband at 256Hz, from 5min before to 55min after infusion start. 5s epochs were rejected if gyroscope data indicated head movement above 10 deg/s or if amplitude was above 200μV. A spectrogram (4s window, 3s overlap) as well as band-limited power (theta: 4-8Hz, alpha: 8-13Hz, beta: 13-25Hz) were computed. Significance of changes was found with a repeated measures analysis of variance (RM-ANOVA) on power in 5min segments together with post-hoc Tukey’s P-values.ResultsAcross the ketamine infusion recordings, there was a significant effect of time (F=3.65, P=0.0105) and Channel*Time interaction (F=3.80, P<0.001) on the EEG spectrum. Effects were largest on temporal electrodes, particularly TP9 in the alpha and theta bands (Figure 1, Table 1).Table 1:Effect sizes (Cohen’s d) and FDR-corrected ANOVA P-values for ketamine effects on each EEG channel and frequency band. P<0.05 was considered significant (bold). n.s. = not significant (P>0.2). Channel / Band TP9AF7AF8TP10Theta1.16 (P=0.019)0.11 (n.s.)0.11 (n.s.)0.42 (P=0.113)Alpha1.41 (P<0.001)0.12 (n.s.)0.17 (n.s.)0.605 (P=0.113)Beta1.19 (P=0.112)0.03 (n.s.)0.08 (n.s.)0.21 (n.s.)Image:ConclusionsIn a routine outpatient setting, sub-anaesthetic ketamine infusions in TRD patients were associated with decreased fronto-temporal EEG alpha and theta power. Future work should assess the potential of low-cost routine EEG, and alpha desaturation specifically, to inform individualised ketamine treatment.Disclosure of InterestNone Declared

Unique Effects of (R)-Ketamine Compared to (S)-Ketamine on EEG Theta Power in Rats.

Differences in the pharmacological effects of (S)-ketamine and (R)-ketamine are at the focus of research. Clinical data and our rat studies confirmed the antidepressant effect of (S)- but not (R)-ketamine, with similar differences in quantitative electroencephalogram (EEG) and sleep effects. In contrast, studies mainly on mice showed some stronger, preferable effects of (R)-ketamine. EEG theta (5-9 Hz) rhythm originates from the hippocampus, and its power is associated with cognitive functions, attention, and decreased anxiety. To find a brain parameter that is not associated with the antidepressant effect of drugs and may confirm potent in vivo effects of (R)-ketamine in rats, theta EEG power-inducing effects of the two enantiomers were measured and compared for 23 h. EEG-equipped Wistar rats were treated with (R)-ketamine (7.5, 15, 30 mg/kg i.p.), (S)-ketamine (7.5 and 15 mg/kg i.p.), or vehicle at the beginning of the passive phase. Frontoparietal EEG, electromyogram, and motor activity were recorded. (R)-ketamine but not (S)-ketamine dose-dependently increased EEG theta power during wakefulness and rapid eye movement (REM) sleep for 23 h. These results suggest that (R)-ketamine has an effect on a hippocampal function that was not affected by (S)-ketamine and may be associated with neural plasticity and memory encoding.

Feasibility of real world end‐points of functional neurophysiology in Alzheimer’s disease dementia

AbstractBackgroundClinic‐based biomarkers are effective in tracking disease progression in clinical research, but do not scale to support public health needs or large‐scale real‐world studies. Purely digital markers are scalable but lack the objectivity and neurobiological grounding of clinical measures. These first results of a real‐world feasibility study demonstrate that objective measures of a range of domains including EEG (Figure 1) are user‐friendly and suitable for repeated at‐home use by patients and older controls.Method60 patients and 60 matched controls are being recruited for a 1‐year repeated sampling study in the UK. Patients were clinically assessed to have mild Alzheimer’s type dementia. Participants were asked to complete about 30 minutes of behavioral tasks including memory, executive function, affective processing and language, while synchronized EEG was recorded using a self‐applied dry‐sensor headset. This interim data is from an initial 2‐week burst sampling period, for the first half of the cohorts.ResultAdherence was 76% for the dementia group (N = 29, mean age = 75; ADAS = Cog 24.3) and 88% for the control group (N = 36, mean age = 71; ADAS = Cog 7.8). A symbol substitution task (executive function) differentiated strongly between groups (t(53) = 6.9), and correlated highly with a conventional pen‐and‐paper DSST benchmark (rho = 0.79). An associative memory task also patterned strongly with disease status (t(54) = 5.7) and correlated with the Verbal Paired Associates benchmark (rho = 0.76). The grand average P300 ERP, elicited by a gamified 2‐stimulus oddball task, showed characteristic features of sensory and higher cognitive processing (Figure 2). As expected in the patient group, the P300 was reduced and delayed; and the resting‐state EEG theta and alpha power were enhanced and reduced, respectively. Radar plots (Figure 3), illustrate the pattern observed across domains in one representative Alzheimer’s patient and one control. Data from a fronto‐temporal dementia sister study is included for comparison.ConclusionInterim data from this first‐in‐class study suggest that patients with mild Alzheimer’s disease dementia are capable and willing to participate in intensive home‐based functional neurophysiology studies, if technology is designed to be engaging and easy to use. Initial examination of the data aligns with established benchmarks, constituting positive early evidence for construct validity and technical feasibility.

Feasibility of real world end‐points of functional neurophysiology in Alzheimer’s disease dementia

AbstractBackgroundClinic‐based biomarkers are effective in tracking disease progression in clinical research, but do not scale to support public health needs or large‐scale real‐world studies. Purely digital markers are scalable but lack the objectivity and neurobiological grounding of clinical measures. These first results of a real‐world feasibility study demonstrate that objective measures of a range of domains including EEG (Figure 1) are user‐friendly and suitable for repeated at‐home use by patients and older controls.Method60 patients and 60 matched controls are being recruited for a 1‐year repeated sampling study in the UK. Patients were clinically assessed to have mild Alzheimer’s type dementia. Participants were asked to complete about 30 minutes of behavioral tasks including memory, executive function, affective processing and language, while synchronized EEG was recorded using a self‐applied dry‐sensor headset. This interim data is from an initial 2‐week burst sampling period, for the first half of the cohorts.ResultAdherence was 76% for the dementia group (N = 29, mean age = 75; ADAS = Cog 24.3) and 88% for the control group (N = 36, mean age = 71; ADAS = Cog 7.8). A symbol substitution task (executive function) differentiated strongly between groups (t(53) = 6.9), and correlated highly with a conventional pen‐and‐paper DSST benchmark (rho = 0.79). An associative memory task also patterned strongly with disease status (t(54) = 5.7) and correlated with the Verbal Paired Associates benchmark (rho = 0.76). The grand average P300 ERP, elicited by a gamified 2‐stimulus oddball task, showed characteristic features of sensory and higher cognitive processing (Figure 2). As expected in the patient group, the P300 was reduced and delayed; and the resting‐state EEG theta and alpha power were enhanced and reduced, respectively. Radar plots (Figure 3), illustrate the pattern observed across domains in one representative Alzheimer’s patient and one control. Data from a fronto‐temporal dementia sister study is included for comparison.ConclusionInterim data from this first‐in‐class study suggest that patients with mild Alzheimer’s disease dementia are capable and willing to participate in intensive home‐based functional neurophysiology studies, if technology is designed to be engaging and easy to use. Initial examination of the data aligns with established benchmarks, constituting positive early evidence for construct validity and technical feasibility.

Influence of and Resistance to Nudge Decision-Making in Professionals

This study investigated how professionals’ decision-making is influenced by nudging and their resistance to such a form of conditioning. A total of 61 professionals performed a nudge task in which three different scenarios related to wellbeing and sustainable behaviours were presented to the participants under boosted and soft nudge conditions. After the presentation of each scenario, participants were required to decide between two options of choice: one choice was more nudge-induced, the other was not. Electrophysiological (EEG), autonomic, behavioural, and self-report data were collected to determine the correlates of resistance with nudge conditions. The findings showed that professionals’ resistance to nudging is high and not influenced by boosted or soft nudges. Also, while the generalized increase in EEG delta, theta, and beta power localized and lateralized in the right temporoparietal regions can lay the foundation of “the neural architecture” of resistance to nudging, the significant increase in SCR for the boosted compared to soft condition highlighted the pivotal role of this marker as the only indicator that differentiates the two nudge conditions. Overall, evaluating the correlates of the resistance to nudge can be useful to render professionals aware of the explicit and implicit factors to be strengthened to resist to such form of conditioning.

The Relationship Between Theta Power, Theta Asymmetry and the Effect of Escitalopram in the Treatment of Depression.

Only about one-third of depressed patients respond to initial antidepressant treatment. Therefore, it is crucial to find effective predictors of antidepressants. The purpose of our study was to learn the relationship between EEG theta power, theta asymmetry, and the efficacy of escitalopram. The study included 34 patients with depression. Before and after each patient's course of treatment, EEG data was gathered. Both the Hamilton Anxiety Scale (HAMA) and the 17-item Hamilton Depression Scale (HAMD-17) were evaluated simultaneously. The natural logarithm of right frontal theta power minus left frontal theta power was used to calculate inter-electrode theta asymmetry (AT). First, our study found no statistically significant difference between intra-electrode theta power and inter-electrode AT before and after treatment (P ≥ 0.05). When we later looked at the data regarding treatment effects, the findings revealed that patients (n = 9) who did not respond to treatment had lower baseline theta power at C4 [6.190 (2.000, 12.990) vs 15.800 (7.255, 22.330), z = -2.166, P = 0.030]. The two groups had no difference in other electrodes (P ≥ 0.05). The AT of C3/C4 in non-responders (n = 9) was lower [0.012 (0.795) vs 0.733 (0.539), t = -3.224, P = 0.005]. However, there was no difference in inter-electrode AT between the two groups in F3/F4 and F7/F8 (P ≥ 0.05). We finally show that the theta power at C4 was negatively correlated with HAMD scores before treatment (r = -0.346, P = 0.045). Our findings determined that increased theta power and positive asymmetry in the right frontal-central area correlate with favourable escitalopram treatment, providing a basis for finding predictive markers for antidepressants.

Ten-month-old infants’ neural tracking of naturalistic speech is not facilitated by the speaker’s eye gaze

Eye gaze is a powerful ostensive cue in infant-caregiver interactions, with demonstrable effects on language acquisition. While the link between gaze following and later vocabulary is well-established, the effects of eye gaze on other aspects of language, such as speech processing, are less clear. In this EEG study, we examined the effects of the speaker’s eye gaze on ten-month-old infants’ neural tracking of naturalistic audiovisual speech, a marker for successful speech processing. Infants watched videos of a speaker telling stories, addressing the infant with direct or averted eye gaze. We assessed infants’ speech-brain coherence at stress (1–1.75 Hz) and syllable (2.5–3.5 Hz) rates, tested for differences in attention by comparing looking times and EEG theta power in the two conditions, and investigated whether neural tracking predicts later vocabulary. Our results showed that infants’ brains tracked the speech rhythm both at the stress and syllable rates, and that infants’ neural tracking at the syllable rate predicted later vocabulary. However, speech-brain coherence did not significantly differ between direct and averted gaze conditions and infants did not show greater attention to direct gaze. Overall, our results suggest significant neural tracking at ten months, related to vocabulary development, but not modulated by speaker’s gaze.

Cognitive Workload of Novice Forklift Truck Drivers in VR-based Training

There is increasing use of Virtual Reality (VR) to train forklift truck operators but a lack of sufficient understanding of how cognitive workload changes with respect to different task demands in VR-based training. In this study, 19 novice participants completed three forklift driving lessons with varying difficulty levels (low, medium, and high) using a VR simulator. To examine the effect of repeated training on cognitive workload, two sessions were repeated by participants using the same procedures. Cognitive workload was assessed with objective (electroencephalogram [EEG] activity) and subjective (NASA-TLX) measurements. EEG theta power and NASA-TLX (mental workload) scores were significantly higher for high than low difficulty levels. However, both EEG and NASA-TLX responses were reduced with repeated training in the second session. These findings highlight the effectiveness of EEG in continuous monitoring of workload variation caused by task difficulty and implementing training programs to moderate cognitive workload for forklift operators.

Assisting schizophrenia diagnosis using clinical electroencephalography and interpretable graph neural networks: a real-world and cross-site study.

Schizophrenia (SCZ) is a chronic and serious mental disorder with a high mortality rate. At present, there is a lack of objective, cost-effective and widely disseminated diagnosis tools to address this mental health crisis globally. Clinical electroencephalogram (EEG) is a noninvasive technique to measure brain activity with high temporal resolution, and accumulating evidence demonstrates that clinical EEG is capable of capturing abnormal SCZ neuropathology. Although EEG-based automated diagnostic tools have obtained impressive performance on individual datasets, the transportability of potential EEG biomarkers in cross-site real-world application is still an open question. To address the challenges of small sample sizes and population heterogeneity, we develop an advanced interpretable deep learning model using multimodal clinical EEG features and demographic information as inputs to graph neural networks, and further propose different transfer learning strategies to adapt to different clinical scenarios. Taking the disease discrimination of health control (HC) and SCZ with 1030 participants as a use case, our model is trained on a small clinical dataset (N = 188, Chinese) and enhanced using a large-scale public dataset (N = 508, American) of adult participants. Cross-site validation from an independent dataset of adult participants (N = 157, Chinese) produced stable performance, with AUCs of 0.793-0.852 and accuracies of 0.786-0.858 for different SCZ prevalence, respectively. In addition, cross-site validation from another dataset of adolescent boys (N = 84, Russian) yielded an AUC of 0.702 and an accuracy of 0.690. Moreover, feature visualization further revealed that the ranking of feature importance varied significantly among different datasets, and that EEG theta and alpha band power appeared to be the most significant and translational biomarkers of SCZ pathology. Overall, our promising results demonstrate the feasibility of SCZ discrimination using EEG biomarkers in multiple clinical settings.

Cognitive Load Estimation in VR Flight Simulator.

This paper discusses the design and development of a low-cost virtual reality (VR) based flight simulator with cognitive load estimation feature using ocular and EEG signals. Focus is on exploring methods to evaluate pilot's interactions with aircraft by means of quantifying pilot's perceived cognitive load under different task scenarios. Realistic target tracking and context of the battlefield is designed in VR. Head mounted eye gaze tracker and EEG headset are used for acquiring pupil diameter, gaze fixation, gaze direction and EEG theta, alpha, and beta band power data in real time. We developed an AI agent model in VR and created scenarios of interactions with the piloted aircraft. To estimate the pilot's cognitive load, we used low-frequency pupil diameter variations, fixation rate, gaze distribution pattern, EEG signal-based task load index and EEG task engagement index. We compared the physiological measures of workload with the standard user's inceptor control-based workload metrics. Results of the piloted simulation study indicate that the metrics discussed in the paper have strong association with pilot's perceived task difficulty.

Investigating the role of the right inferior frontal gyrus in control perception: A double-blind cross-over study using ultrasonic neuromodulation

Being able to control inner and environmental states is a basic need of living creatures. The perception of such control is based on the perceived ratio of outcome probabilities given the presence and the absence of agentic behavior. If an organism believes that options exist to change the probability of a given outcome, control perception (CP) may emerge. Nonetheless, regarding this model, not much is known about how the brain processes CP from this information. This study uses low-intensity transcranial focused ultrasound neuromodulation in a randomized-controlled double blind cross-over design to investigate the impact of the right inferior frontal gyrus of the lateral prefrontal cortex (lPFC) on this process. 39 healthy participants visited the laboratory twice (once in a sham, once in a neuromodulation condition) and rated their control perception regarding a classical control illusion task. EEG alpha and theta power density were analyzed in a hierarchical single trial-based mixed modeling approach. Results indicate that the litFUS neuromodulation changed the processing of stimulus probability without changing CP. Furthermore, neuromodulation of the right lPFC was found to modulate mid-frontal theta by altering its relationship with self-reported effort and worrying. While these data indicate lateral prefrontal sensitivity to stimulus probability, no evidence emerged for the dependency of CP on this processing.

GABA-Positive Astrogliosis in Sleep-Promoting Areas Associated with Sleep Disturbance in 5XFAD Mice.

Sleep disturbances, a debilitating symptom of Alzheimer's disease (AD), are associated with neuropathological changes. However, the relationship between these disturbances and regional neuron and astrocyte pathologies remains unclear. This study examined whether sleep disturbances in AD result from pathological changes in sleep-promoting brain areas. Male 5XFAD mice underwent electroencephalography (EEG) recordings at 3, 6, and 10 months, followed by an immunohistochemical analysis of three brain regions associated with sleep promotion. The findings showed that 5XFAD mice demonstrated reduced duration and bout counts of nonrapid eye movement (NREM) sleep by 6 months and reduced duration and bout counts of rapid eye movement (REM) sleep by 10 months. Additionally, peak theta EEG power frequency during REM sleep decreased by 10 months. Sleep disturbances correlated with the total number of GFAP-positive astrocytes and the ratio of GFAP- and GABA-positive astrocytes across all three sleep-associated regions corresponding to their roles in sleep promotion. The presence of GABRD in sleep-promoting neurons indicated their susceptibility to inhibition by extrasynaptic GABA. This study reveals that neurotoxic reactive astrogliosis in NREM and REM sleep-promoting areas is linked to sleep disturbances in 5XFAD mice, which suggests a potential target for the treatment of sleep disorders in AD.

0409 Is insomnia with objective short sleep duration related to insufficient sleep drive or physiological hyperarousal?

Abstract Introduction IInsomnia with objective short sleep duration (OSSD) was found to be associated with higher risks of cardiometabolic disorders, and was therefore proposed to be a phenotype associated with higher physiological hyperarousal. Previous studies further reported that insomnia with OSSD had higher autonomic arousal as measured by heart rate variability (HRV) during sleep. Since sleep duration could be determined by the interplay of arousal and sleep drive and HRV during sleep could be influenced by sleep staging and quality, the present study examined the level of arousal and sleep drive prior to sleep with EEG power and HRV to further understand the phenotyping of insomnia. Methods Ninety-four insomnia patients participated in the study and went through one night of 8-hour PSG recording. They were divided, with a cut-off of PSG total sleep time of 6 hours, into two groups: an OSSD group (N=26; mean age=37.0 ±10.3; M:F=7:19; TST=286.21±87.21 min) and an objective normal sleep duration (ONSD) group (N=68, mean age=32.95 ±10.05, M:F=12: 56, TST=414.4±28.9 min). Resting-state EEG and EKG were recorded for a 6-min period, 3-min eye-opened (EO) with fixation focus and 3 mins eye-closed (EC), prior to bedtime. Results T-tests showed no significant difference in HRV measures (SDNN, RMSD, LF, HF, LF/HF) between the two groups, but shorter R-R interval for OSSD group than ONSD group. Mann-Whitney tests for EEG power showed significantly lower theta power at F3, F4, C3, C4, and O2, and higher sigma power at F3, C3, C4, O1, and O2 during EC, as well as lower theta power at C3 and higher sigma power at O2 during EO for OSSD group in comparison to ONSD group. Conclusion The results partially support that insomnia with OSSD is associated with physiological hyperarousal as indicated by faster heart rate and higher high frequency EEG power prior to sleep. However, the lower EEG theta power prior to sleep suggest that lower homeostatic sleep drive may also play a role for the insomnia with short objective sleep duration. Support (if any) Supported by Taiwan National Science and Technology Council

Gamification of an n-back working memory task – Is it worth the effort? An EEG and eye-tracking study

Gamification of cognitive tasks might positively affect emotional-motivational factors (emotional design perspective) or negatively affect cognitive factors like working memory load (minimalistic design perspective). The current study examined the effects of gamification in a spatial n-back working memory task on task performance, task load (i.e., working memory load and effort), and subjective task experience. Task load was assessed by the physiological process measures pupil dilation and EEG theta (4–6 Hz) and alpha (8–13 Hz) frequency band power. Gamification was achieved by elements of emotional design (i.e., the visual screen design using, e.g., color, cartoon figures as n-back stimuli, and a narrative embedding of the task). While EEG and eye-tracking were recorded, participants conducted gamified and non-gamified 1-back and 2-back load levels. The gamification resulted in positive effects on subjective task experience and affect. Despite these effects, gamification did not affect task performance and task load. However, exploratory analyses revealed increased EEG theta power at right-parietal electrodes for gamified task versions compared to non-gamified ones. Potentially, this effect might indicate participants' increased effort or concentration in the gamified n-back task. In line with an emotional design perspective, gamification positively altered subjective task experience and affect without hampering task performance and therefore justify the extra effort of implementing game elements.

Power spectral analysis of the sleep electroencephalogram in positional obstructive sleep apnea

Objective/BackgroundPrevious studies have shown that obstructive sleep apnoea (OSA) is associated with reduced delta EEG and increased beta EEG power and increased EEG slowing ratio. There are however no studies that explore differences in sleep EEG between positional obstructive sleep apnoea (pOSA) and non-positional obstructive sleep apnoea (non-pOSA) patients. Patients/methods556 of 1036 consecutive patients (246 of 556 were female) undertaking polysomnography (PSG) for the suspicion of OSA met the inclusion criteria for this study. We calculated power spectra of each sleep epoch using Welch's method with ten, 4-s overlapping windows. Outcome measures such as Epworth Sleepiness Scale, SF-36 Quality of Life, Functional Outcomes of Sleep Questionnaire and Pyschomotor Vigilance Task were compared between the groups. ResultsPatients with pOSA had greater delta EEG power in NREM and greater N3 proportions compared to their non-pOSA counterparts. There were no differences in theta (4–8Hz), alpha (8–12Hz), sigma (12–15Hz) or beta (15–25Hz) EEG power or EEG slowing ratio between the two groups. There were also no differences in the outcome measures between these two groups. The division of pOSA into spOSA and siOSA groups showed better sleep parameters in siOSA but with no difference in sleep power spectra. ConclusionsThis study partially supports our hypothesis in showing that pOSA, compared to non-pOSA, is associated with increased delta EEG power but did not show any variation to beta EEG power or EEG slowing ratio. This limited improvement in sleep quality did not translate to measurable changes to outcomes, suggesting beta EEG power or EEG slowing ratio may be key factors.