Individual differences in subjective and objective alertness  during sleep deprivation are stable and unrelated

This study examines the individual reproducibility of alterations of subjective, objective, and EEG measures of alertness during 27 h of continuous wakefulness and analyzes their interrelationships. Eight subjects were studied twice under similar constant-routine conditions. Scales and performance tasks were administered at hourly intervals to define temporal changes in subjective and objective alertness. The wake EEG was recorded every 2 h, 2 min with eyes open and 2 min with eyes closed. Plasma glucose and melatonin levels were measured to estimate brain glucose utilization and individual circadian phase, respectively. Decrements of subjective alertness and performance deficits were found to be highly reproducible for a given individual. Remarkably, there was no relationship between the impairments of subjective and objective alertness. With increased duration of wakefulness, EEG activity with eyes closed increased in the delta range and decreased in the alpha range, but the magnitudes of these changes were also unrelated. These findings indicate that sleep deprivation has highly reproducible, but independent, effects on brain mechanisms controlling subjective and objective alertness.

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Unique Contributions of Brain Stimulation to the Study of Consciousness: Where Neuroscience Meets Philosophy

CNS Spectrums ◽

10.1017/s1092852900027425 ◽

2010 ◽

Vol 15 (3) ◽

pp. 154-156

Author(s):

Stefano Pallanti

Keyword(s):

Ancient Greek ◽

Eyes Closed ◽

Technical Procedure ◽

Eyes Open ◽

Definition Of ◽

The Individual ◽

The Brain ◽

Integrated Information Theory ◽

Field Of Inquiry ◽

Integrated Information

True progress in understanding how experience arises from the brain has been relatively slow when viewed from a historical perspective. Recently, several technologies to study and stimulate the brain have been applied to this field of inquiry. Such progress was made only 2,500 years after the ancient Greek philosopher Parmenides first adopted a technical procedure involving the application of formal logic instruments to explore the perception of experiences.At the phenomenological level, consciousness has been referred to as “what vanishes every night when we fall into dreamless sleep and reappears when we wake up or when we dream. It is also all we are and all we have: lose consciousness and, as far as you are concerned, your own self, and the entire world dissolves into nothingness”. According to the integrated information theory, consciousness is integrated information.The term “consciousness” therefore has two key senses: wakefulness and awareness. Wakefulness is a state of consciousness distinguished from coma or sleep. Having one's eyes open is generally an indication of wakefulness and we usually assume that anyone who is awake will also be aware. Awareness implies not merely being conscious but also being conscious of something. The broad definition of consciousness includes a large range of processes that we normally regard as unconscious (eg, blindsight or priming by neglected or masked stimuli).Both sleep and anesthesia are reversible states of eyes-closed unresponsiveness to environmental stimuli in which the individual lacks both wakefulness and awareness. In contrast to sleep, where sufficient stimulation will return the individual to wakefulness, even the most vigorous exogenous stimulation cannot produce awakening in a patient under an adequate level of general anesthesia.

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Relationship between alertness, performance, and body temperature in humans

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00205.2002 ◽

2002 ◽

Vol 283 (6) ◽

pp. R1370-R1377 ◽

Cited By ~ 202

Author(s):

Kenneth P. Wright ◽

Joseph T. Hull ◽

Charles A. Czeisler

Keyword(s):

Body Temperature ◽

Human Performance ◽

Reaction Times ◽

Biological Time ◽

Circadian Phase ◽

Neurobehavioral Function ◽

Improved Performance ◽

And Performance ◽

Subjective Alertness ◽

The Relationship

Body temperature has been reported to influence human performance. Performance is reported to be better when body temperature is high/near its circadian peak and worse when body temperature is low/near its circadian minimum. We assessed whether this relationship between performance and body temperature reflects the regulation of both the internal biological timekeeping system and/or the influence of body temperature on performance independent of circadian phase. Fourteen subjects participated in a forced desynchrony protocol allowing assessment of the relationship between body temperature and performance while controlling for circadian phase and hours awake. Most neurobehavioral measures varied as a function of internal biological time and duration of wakefulness. A number of performance measures were better when body temperature was elevated, including working memory, subjective alertness, visual attention, and the slowest 10% of reaction times. These findings demonstrate that an increased body temperature, associated with and independent of internal biological time, is correlated with improved performance and alertness. These results support the hypothesis that body temperature modulates neurobehavioral function in humans.

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Development of Frontal EEG Differences Between Eyes-Closed and Eyes-Open Resting Conditions in Children: Data From a Single-Channel Dry-Sensor Portable Device

Clinical EEG and Neuroscience ◽

10.1177/1550059420946648 ◽

2020 ◽

pp. 155005942094664

Author(s):

Stuart J. Johnstone ◽

Han Jiang ◽

Li Sun ◽

Jeffrey M. Rogers ◽

Joaquin Valderrama ◽

...

Keyword(s):

Single Channel ◽

Developmental Change ◽

Alpha Power ◽

Top Down ◽

Bottom Up ◽

Individual Level ◽

Eyes Closed ◽

Beta Power ◽

Eyes Open ◽

The Individual

Changes in EEG when moving from an eyes-closed to an eyes-open resting condition result from bottom-up sensory processing and have been referred to as activation. In children, activation is characterized by a global reduction in alpha, frontally present reductions for delta and theta, and a frontal increase for beta. The present study aimed to replicate frontal EEG activation effects using single-channel, dry-sensor EEG, and to extend current understanding by examining developmental change in children. Frontal EEG was recorded using a single-channel, dry-sensor EEG device while 182 children aged 7 to 12 years completed eyes-closed resting (EC), eyes-open resting (EO), and focus (FO) tasks. Results indicated that frontal delta, theta, and alpha power were reduced, and frontal beta power was increased, in the EO compared with the EC condition. Exploratory analysis of a form of top-down activation showed that frontal beta power was increased in the FO compared with to the EO condition, with no differences for other bands. The activation effects were robust at the individual level. The bottom-up activation effects reduced with age for frontal delta and theta, increased for frontal alpha, with no developmental change for top-down or bottom-up frontal beta activation. These findings contribute further to validation of the single-channel, dry-sensor, frontal EEG and provide support for use in a range of medical, therapeutic, and clinical domains.

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Phase Difference Between Chronotypes in Self-Reported Maximum of Alertness Rhythm

Journal of Psychophysiology ◽

10.1027/0269-8803/a000116 ◽

2014 ◽

Vol 28 (4) ◽

pp. 242-256 ◽

Cited By ~ 8

Author(s):

Arcady A. Putilov ◽

Olga G. Donskaya ◽

Evgeniy G. Verevkin

Keyword(s):

Phase Difference ◽

External Validity ◽

Time Course ◽

Circadian Timing ◽

Circadian Phase ◽

Eyes Closed ◽

Power Difference ◽

Time Courses ◽

Subjective Alertness ◽

Healthy Participants

An objective physiological predictor of self-reported chronotypological differences in circadian timing of alertness peak (> 5 hr) has not been yet identified. Our goals were to establish external validity of such a predictor, and to explain the observations of inequality of chronotypological differences in alertness peak and bed/rising times (> 5 and < 3 hr, respectively). The resting electroencephalogram was recorded at 3-hr intervals during 24-hr sustained wakefulness of 130 healthy participants. An objective index (alpha-theta power difference) was calculated for the eyes closed section of each record. The time course of subjective alertness-sleepiness was compared with the time course of the objective index and simulated with a rhythmostatic model. External validity of the objective predictor of chronotypological differences was supported by the resemblance between the time courses, and the simulations revealed contribution of other than circadian phase parameters of the chronoregulatory processes to the appearance of > 5-hr chronotypological difference between alertness peaks.

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An EEG Investigation of the Impact of Noise on Attention

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.779-780.1731 ◽

2013 ◽

Vol 779-780 ◽

pp. 1731-1736

Author(s):

Li Ho Tseng ◽

Ming Tai Cheng ◽

Shih Tsung Chen ◽

Jyi Faa Hwang ◽

Chia Ju Chen ◽

...

Keyword(s):

Noise Exposure ◽

Brain Activity ◽

Phase Coherence ◽

Noisy Environment ◽

Eyes Closed ◽

Eyes Open ◽

Eeg Power ◽

And Performance ◽

Coherence Estimation ◽

The Impact

During the past two decades, most researchers employed a questionnaire to characterize the effect of noise on psychosomatic responses. Developments in physiological techniques offer a non-invasive method for recording brain activity with electroencephalography (EEG). This method for assessing the impact of noise on attention is growing in popularity. The aim of this study was to investigate brain activity changes in response to noise exposure during attention-demanding tasks by using EEG power and phase coherence estimation. We hypothesized that brain rhythms could be affected by environmental stimuli and would be reflected in the EEG power and phase coherence. Nineteen healthy right-handed university students (mean age = 21.5 ± 2.0 years) participated in this study. The experiment comprised recording EEG data for participants in the following steps: rest with eyes closed (< 50 dBA), rest with eyes open, listening in a noisy environment (85 dBA), performance on an attention-demanding task in a quiet environment (< 50 dBA), and performance on an attention-demanding task in a noisy environment (85 dBA). Significant differences were observed between stages, and the participants performed more effectively in the quiet environment, where they showed higher rates of correct responses (p <.05). From the assessment of the EEG power and phase coherence estimation, the study demonstrated the following: (1) Alpha-2 (10-13 Hz) power and phase coherence decreased when participants shifted from closed eyes to open eyes, while theta power increased. (2) In contrast, during the noise exposure phase, whether during an attention-demanding task or not, beta (13-30 Hz) phase coherence decreased in the brain, but theta phase coherence was not affected compared to the results in the quiet environment. We suggest that the high frequency of neural synchronization is relevant for cognitive performance, and that participants at risk for selective attention are affected by noise exposure.

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A systematic review and meta-analysis on efficacy of exercise on posture and balance in patients suffering from Diabetic Neuropathy

Current Diabetes Reviews ◽

10.2174/1573399816666200703190437 ◽

2020 ◽

Vol 16 ◽

Author(s):

Neerja Thukral ◽

Jaspreet Kaur ◽

Manoj Malik

Keyword(s):

Diabetes Mellitus ◽

Diabetic Neuropathy ◽

Meta Analysis ◽

Berg Balance Scale ◽

Risk Of Bias ◽

Core Stability ◽

Balance Scale ◽

Eyes Closed ◽

Significant Difference ◽

Eyes Open

Background: Peripheral neuropathy is a major and chronic complication of diabetes mellitus affecting more than 50% of patients suffering from diabetes. There is involvement of both large and small diameter nerve fibres leading to altered somatosensory and motor sensations, thereby causing impaired balance and postural instability. Objective: To assess the effects of exercises on posture and balance in patients suffering from diabetes mellitus. Method: Mean changes in Timed Up and Go test(TUGT), Berg Balance Scale and Postural Sway with eyes open and eyes closed on Balance System were primary outcome measures. RevMan 5.3 software was used for the meta-analyses. Eighteen randomized controlled trials met the selection criteria and were included in the study. All the studies ranked high on PEDro Rating scale. Risk of bias was assessed by Cochrane collaboration tool of risk of bias. Included studies had low risk of bias. Sixteen RCT’s were included for the meta-analysis. Result: Results of meta-analysis showed that there was statistically significant improvement in TUGT with p≤ 0.05 and substantial heterogeneity (I 2 = 84%, p < 0.00001) in experimental group as compared to control group. There was statistically significant difference in Berg Balance Scale scores and heterogeneity of I 2 = 62%, p < 0.00001 and significant changes in postural stability (eyes open heterogeneity of I 2 = 100%, p =0.01 and eyes closed, heteogeneity I 2 = 0%, p =0.01). Sensitivity analysis causes change in heterogeneity. Conclusion: It can be concluded that various exercises like balance training, core stability, Tai-Chi, proprioceptive training etc. have a significant effect in improving balance and posture in diabetic neuropathy.

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Gender Differences in Postural Stability among 13-Year-Old Alpine Skiers

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17113859 ◽

2020 ◽

Vol 17 (11) ◽

pp. 3859 ◽

Cited By ~ 1

Author(s):

Agnieszka D. Jastrzębska

Keyword(s):

Gender Differences ◽

Postural Balance ◽

Lactate Concentration ◽

Blood Lactate Concentration ◽

Body Sway ◽

Foot Pressure ◽

Eyes Closed ◽

Before And After ◽

Eyes Open ◽

Alpine Skiers

This experiment examined changes in body sway after Wingate test (WAnT) in 19 adolescents practicing alpine skiing, subjected to the same type of training load for 4–5 years (10 girls and nine boys). The postural examinations were performed with eyes open (EO), eyes closed (EC), and sway reverenced vision (SRV) in the medial-lateral (ML) and anterior-posterior (AP) planes. The displacement of center of foot pressure (CoP), range of sway (RS), mean sway velocity (MV), way length, and surface area were measured in bipedal upright stance before and after the WAnT to assess the influence of fatigue on postural balance. There were no significant differences in WAnT parameters between girls and boys. Relative peak power (RPP), relative total work (RWtot) were (girls vs. boys) 8.89 ± 0.70 vs. 9.57 ± 1.22 W/kg, p < 0.05 and 227.91 ± 14.98 vs. 243.22 ± 30.24 W/kg, p < 0.05 respectively. The fatigue index (FI) was also on similar level in both genders; however, blood lactate concentration (BLa) was significantly higher in boys (10.35 ± 1.16 mM) than in girls (8.67 ± 1.35 mM) p = 0.007. In the EO examination, statistically significant differences between resting and fatigue conditions in the whole group and after the division into girls and boys were found. In fatigue conditions, significant gender differences were noted for measurements in the ML plane (sway path and RS) and RS in the AP plane. Comparison of the three conditions shows differences between EO vs. EC and SRV in AP plane measured parameters, and for RS in ML plane in rest condition in girls. The strong correlations between FI and CoP parameters mainly in ML plane in the whole group for all examination conditions were noted. By genders, mainly RS in ML plane strongly correlates with FI (r > 0.7). No correlation was found between BLa and CoP parameters (p > 0.06). The presented results indicate that subjecting adolescents of both genders to the same training may reduce gender differences in the postural balance ability at rest but not in fatigue conditions and that girls are significantly superior in postural balance in the ML plane than boys. It was also shown that too little or too much information may be destructive to postural balance in young adolescents.

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Genetic Determinants of Neurobehavioral Responses to Caffeine Administration during Sleep Deprivation: A Randomized, Cross Over Study (NCT03859882)

Genes ◽

10.3390/genes12040555 ◽

2021 ◽

Vol 12 (4) ◽

pp. 555

Author(s):

Mégane Erblang ◽

Fabien Sauvet ◽

Catherine Drogou ◽

Michaël Quiquempoix ◽

Pascal Van Beers ◽

...

Keyword(s):

Sleep Deprivation ◽

Nucleotide Polymorphisms ◽

Genetic Determinants ◽

Placebo Condition ◽

Double Blind ◽

Single Nucleotide ◽

Psychomotor Vigilance Test ◽

Tnf Α ◽

And Performance ◽

Psychomotor Vigilance

This study investigated whether four single nucleotide polymorphisms (SNPs) moderated caffeine effects on vigilance and performance in a double-blind and crossover total sleep deprivation (TSD) protocol in 37 subjects. In caffeine (2 × 2.5 mg/kg/24 h) or placebo-controlled condition, subjects performed a psychomotor vigilance test (PVT) and reported sleepiness every six hours (Karolinska sleepiness scale (KSS)) during TSD. EEG was also analyzed during the 09:15 PVT. Carriers of the TNF-α SNP A allele appear to be more sensitive than homozygote G/G genotype to an attenuating effect of caffeine on PVT lapses during sleep deprivation only because they seem more degraded, but they do not perform better as a result. The A allele carriers of COMT were also more degraded and sensitive to caffeine than G/G genotype after 20 h of sleep deprivation, but not after 26 and 32 h. Regarding PVT reaction time, ADORA2A influences the TSD effect but not caffeine, and PER3 modulates only the caffeine effect. Higher EEG theta activity related to sleep deprivation was observed in mutated TNF-α, PER3, and COMT carriers, in the placebo condition particularly. In conclusion, there are genetic influences on neurobehavioral impairments related to TSD that appear to be attenuated by caffeine administration. (NCT03859882).

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The effect of congenital blindness on resting-state functional connectivity revisited

Scientific Reports ◽

10.1038/s41598-021-91976-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Maria J. S. Guerreiro ◽

Madita Linke ◽

Sunitha Lingareddy ◽

Ramesh Kekunnaya ◽

Brigitte Röder

Keyword(s):

Functional Connectivity ◽

Resting State ◽

Visual Experience ◽

Brain Regions ◽

State Condition ◽

Resting State Functional Connectivity ◽

Congenital Blindness ◽

Eyes Closed ◽

Congenitally Blind ◽

Eyes Open

AbstractLower resting-state functional connectivity (RSFC) between ‘visual’ and non-‘visual’ neural circuits has been reported as a hallmark of congenital blindness. In sighted individuals, RSFC between visual and non-visual brain regions has been shown to increase during rest with eyes closed relative to rest with eyes open. To determine the role of visual experience on the modulation of RSFC by resting state condition—as well as to evaluate the effect of resting state condition on group differences in RSFC—, we compared RSFC between visual and somatosensory/auditory regions in congenitally blind individuals (n = 9) and sighted participants (n = 9) during eyes open and eyes closed conditions. In the sighted group, we replicated the increase of RSFC between visual and non-visual areas during rest with eyes closed relative to rest with eyes open. This was not the case in the congenitally blind group, resulting in a lower RSFC between ‘visual’ and non-‘visual’ circuits relative to sighted controls only in the eyes closed condition. These results indicate that visual experience is necessary for the modulation of RSFC by resting state condition and highlight the importance of considering whether sighted controls should be tested with eyes open or closed in studies of functional brain reorganization as a consequence of blindness.

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Gait Stability Measurement by Using Average Entropy

Entropy ◽

10.3390/e23040412 ◽

2021 ◽

Vol 23 (4) ◽

pp. 412

Author(s):

Han-Ping Huang ◽

Chang Francis Hsu ◽

Yi-Chih Mao ◽

Long Hsu ◽

Sien Chi

Keyword(s):

Postural Stability ◽

Multiscale Entropy ◽

Gait Stability ◽

Eyes Closed ◽

Stride Interval ◽

Step Interval ◽

Stability Measurement ◽

Eyes Open ◽

Two Measures ◽

Better Than

Gait stability has been measured by using many entropy-based methods. However, the relation between the entropy values and gait stability is worth further investigation. A research reported that average entropy (AE), a measure of disorder, could measure the static standing postural stability better than multiscale entropy and entropy of entropy (EoE), two measures of complexity. This study tested the validity of AE in gait stability measurement from the viewpoint of the disorder. For comparison, another five disorders, the EoE, and two traditional metrics methods were, respectively, used to measure the degrees of disorder and complexity of 10 step interval (SPI) and 79 stride interval (SI) time series, individually. As a result, every one of the 10 participants exhibited a relatively high AE value of the SPI when walking with eyes closed and a relatively low AE value when walking with eyes open. Most of the AE values of the SI of the 53 diseased subjects were greater than those of the 26 healthy subjects. A maximal overall accuracy of AE in differentiating the healthy from the diseased was 91.1%. Similar features also exists on those 5 disorder measurements but do not exist on the EoE values. Nevertheless, the EoE versus AE plot of the SI also exhibits an inverted U relation, consistent with the hypothesis for physiologic signals.

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