Level Of Alertness Research Articles

Magnetoencephalographic signatures of hierarchical rule learning in newborns

Estimating the extent to which newborn humans process input from their environment, especially regarding the depth of processing, is a challenging question. To approach this problem, we measured brain responses in 20 newborns with magnetoencephalography (MEG) in a “local-global” auditory oddball paradigm in which two-levels of hierarchical regularities are presented. Results suggest that infants in the first weeks of life are able to learn hierarchical rules, yet a certain level of vigilance seems to be necessary. Newborns detected violations of the first-order regularity and displayed a mismatch response between 200−400 ms. Violations of the second-order regularity only evoked a late response in newborns in an active state, which was expressed by a high heart rate variability. These findings are in line with those obtained in human adults and older infants suggesting a continuity in the functional architecture from term-birth on, despite the immaturity of the human brain at this age.

"I Don't Have to Think About Watching the Ground": A Qualitative Study Exploring the Concept of Vigilance as an Important Outcome for Ankle Reconstruction.

To understand patients' experiences of ankle reconstruction for treatment of end-stage ankle osteoarthritis. Individuals were recruited from a cohort of individuals who had undergone total ankle replacement or ankle fusion. English-speaking individuals who had surgery at least 1 year prior were invited to participate. Semistructured, face-to-face interviews relying on a phenomenological approach were conducted in a private hospital clinic room. A total of 25 adults (12 women, 13 men), ages 25-82 years, were interviewed for 1-2 hours. Participants commonly described a state of having to keep careful watch for potential environmental challenges. Vigilance was related to ongoing symptoms (i.e., pain, stiffness) and concerns regarding balance, stability, and potential damage to the fused ankle or implant. Vigilance was described along a continuum, with higher levels associated with stress and mental exhaustion. Vigilance affected participants' perception of their surgical outcome, with high vigilance levels linked to negative perceptions of outcome. The degree to which individuals perceived the need for vigilance was influenced by environmental factors like uneven ground or crowds. Contrary to descriptions of vigilance in the coping literature, vigilance related to ankle reconstruction constituted a situational, rather than dispositional, response. Vigilance and its associated burden are not captured by current instruments. The mental load and worry associated with vigilance was important to patients, distinct from related pain or functional status. Thus, reducing high levels of vigilance appears to be an appropriate target for patient-centered treatment outcomes. A thorough battery of outcome measures for ankle reconstruction should consider this domain.

Eavesdropping of an African ground squirrel on the heterospecific alarm calls of a noisy ground‐nesting bird

AbstractAnimals gather information about their environment from a variety of sources to enable adaptive decision‐making behaviour. Eavesdropping on heterospecific alarm calls enhances predator avoidance, reduces time spent vigilant and allows for more time on daily activities such as foraging. If the information is relevant and reliable, individuals that respond to heterospecific signals may benefit from a wider range of information at a low marginal cost. The Cape ground squirrel (Xerus inauris) and crowned lapwing (Vanellus chilensis) are ground‐dwelling species that are taxonomically distant but share similar predators, habitat and anti‐predatory behaviours. We used playback experiments of the alarm calls produced by conspecifics and lapwings to investigate the vigilance responses of adult female Cape ground squirrels. Squirrels responded with greater vigilance to both squirrel and lapwing alarm calls, and no changes of vigilance levels were observed in response to a control sound. However, contrary to our predictions, changes in vigilance and time to relax did not differ between conspecific versus heterospecific playbacks. The results from our study suggest that squirrels perceive lapwing alarm calls as relevant and reliable information and that responding to it could increase their survival.

Development and consistency of fearfulness in horses from foal to adult

Understanding the development and consistency of behavioural responses across life stages is of both fundamental and applied interest. In horses, fearfulness is particularly important because fear reactions are a major cause of human-horse accidents, and because fear is a negative emotional state with negative consequences for animal welfare and performance. In this study, we investigated the development and consistency of fear reactions in horses, from foal to adult. Twenty-five warmblood stallions of the same age, kept under the same conditions and with minimal human handling, were tested in novel object tests before weaning from the dam (at 5 months) and after weaning, at 1 year (two tests) and again at 3.5 years of age (two tests). Behaviour and heart rate responses were recorded. We found that foals’ expression of alertness towards novel objects was the best predictor of their later behaviour. Some changes in the expression of fear-related behaviour were evident pre and post weaning. Consequently, there were stronger correlations between the post-weaning tests, although these were further separated in time (2.5 years) than the 5 months and 1-year tests (7–9 months). Further, there were positive correlations in the horses’ reactions in the two tests at 1 year and at 3 years (e.g. heart rate: rs = 0.82, P < 0.001 and alertness: rs = 0.68, P < 0.001), suggesting that fearfulness is relatively stable across test situations at a certain age point. We conclude that it is possible to test for fearfulness at an early age (before weaning), by measuring the level of alertness towards novel objects. However, responses in post-weaning tests are more consistent. Our findings contribute to an understanding of the expression, development and consistency of fearfulness, which is advantageous for early assessment of behavioural differences in horses.

Evidence for modulation of EEG microstate sequence by vigilance level

The momentary global functional state of the brain is reflected in its electric field configuration and cluster analytical approaches have consistently shown four configurations, referred to as EEG microstate classes A to D. Changes in microstate parameters are associated with a number of neuropsychiatric disorders, task performance, and mental state establishing their relevance for cognition. However, the common practice to use eye-closed resting state data to assess the temporal dynamics of microstate parameters might induce systematic confounds related to vigilance levels. Here, we studied the dynamics of microstate parameters in two independent data sets and showed that the parameters of microstates are strongly associated with vigilance level assessed both by EEG power analysis and fMRI global signal. We found that the duration and contribution of microstate class C, as well as transition probabilities towards microstate class C were positively associated with vigilance, whereas the sign was reversed for microstate classes A and B. Furthermore, in looking for the origins of the correspondence between microstates and vigilance level, we found Granger-causal effects of vigilance levels on microstate sequence parameters. Collectively, our findings suggest that duration and occurrence of microstates have a different origin and possibly reflect different physiological processes. Finally, our findings indicate the need for taking vigilance levels into consideration in resting-sate EEG investigations.

The Analysis of Occurrences Associated with Air Traffic Volume and Air Traffic Controllers’ Alertness for Fatigue Risk Management

Fatigue is an inevitable hazard in the provision of air traffic services and it has the potential to degrade human performance leading to occurrences. The International Civil Aviation Organization (ICAO) requires air navigation services which providers establish fatigue risk management systems (FRMS) based on scientific principles for the purpose of managing fatigue. To develop effective FRMSs, it is important to investigate the relationship between traffic volume, air traffic management occurrences, and fatigue. Fifty-seven qualified ATCOs from a European Air Navigation Services provider participated in this research by providing data indicating their alertness levels over the course of a 24-hour period. ATCOs' fatigue data were compared against the total of 153 occurrences and 962,328 air traffic volumes from the Eurocontrol TOKAI incident database in 2019. The result demonstrated that ATCO fatigue levels are not the main contributory factor associated with air traffic management occurrences, although fatigue did impact ATCOs' performance. High traffic volume increases ATCO cognitive task load that can surpass available attention resources leading to occurrences. Furthermore, human resilience drives ATCOs to maintain operational safety though they suffer from circadian fatigue. Consequently, FRMS appropriately implemented can be used to mitigate the effects of fatigue. First-line countermeasure strategies should focus on enough rest breaks and roster schedule optimization; secondary strategies should focus on monitoring ATCOs' task loads that may induce fatigue. It is vital to consider traffic volume and ATCOs' alertness levels when implementing effective fatigue risk management protocols.

The Epidemiology of COVID-19 in the Gansu and Jinlin Provinces, China.

The COVID-19 outbreak has become a pandemic. The outbreak was able to be controlled in China by mid-April through the implementation of critical measures; however, significant reverse transmission has resulted in hot spots perturbing prevention and control. To date, there have only been a total of 92 indigenous COVID-19 cases confirmed in the Gansu Province, which is considered to be a consequence of the strict screening approach applied during the outbreak. The emergency response level to COVID-19 were able to be decreased from high to low, despite some relatively minor reverse transmission cases from other countries in March 2020. The stringent preparative measures undertaken by the Gansu authorities, involving high-level, streamlined cooperation between the transportation, quarantine, and medical resource departments, have underpinned this success. There has been an emergence of clusters of freshly infected COVID-19 patients in the Jilin Province in northeast China. The single largest cluster has been in Shulan of the Jilin Province, involving 43 confirmed infections. A strict lockdown was implemented immediately. The source of the current outbreak of COVID-19 is suggested to be travelers returning from Russia. The current strategy from the Chinese authorities is aimed at preventing reverse transmission via international importation to avert a rebound of COVID-19 in China. These data highlight the need for an exceptionally high level of vigilance and for a pre-emptive response that is informative for the development of policy to prevent a second and further waves of infections in general.

The relationship between alertness and spatial attention under simulated shiftwork

Higher and lower levels of alertness typically lead to a leftward and rightward bias in attention, respectively. This relationship between alertness and spatial attention potentially has major implications for health and safety. The current study examined alertness and spatial attention under simulated shiftworking conditions. Nineteen healthy right-handed participants (M = 24.6 ± 5.3 years, 11 males) completed a seven-day laboratory based simulated shiftwork study. Measures of alertness (Stanford Sleepiness Scale and Psychomotor Vigilance Task) and spatial attention (Landmark Task and Detection Task) were assessed across the protocol. Detection Task performance revealed slower reaction times and higher omissions of peripheral (compared to central) stimuli, with lowered alertness; suggesting narrowed visuospatial attention and a slight left-sided neglect. There were no associations between alertness and spatial bias on the Landmark Task. Our findings provide tentative evidence for a slight neglect of the left side and a narrowing of attention with lowered alertness. The possibility that one’s ability to sufficiently react to information in the periphery and the left-side may be compromised under conditions of lowered alertness highlights the need for future research to better understand the relationship between spatial attention and alertness under shiftworking conditions.

Raccoon Vigilance and Activity Patterns When Sympatric with Coyotes

Nonconsumptive effects of predators potentially have negative fitness consequences on prey species through changes in prey behavior. Coyotes (Canis latrans) recently expanded into the eastern United States, and raccoons (Procyon lotor) are a common mesocarnivore that potentially serve as competitors and food for coyotes. We used camera traps at baited sites to quantify vigilance behavior of feeding raccoons and used binomial logistic regression to analyze the effects of social and environmental factors. Additionally, we created raccoon and coyote activity patterns from the camera trap data by fitting density functions based on circular statistics and calculating the coefficient of overlap (Δ). Overall, raccoons were vigilant 46% of the time while foraging at baited sites. Raccoons were more vigilant during full moon and diurnal hours but less vigilant as group size increased and when other species were present. Raccoons and coyotes demonstrated nocturnal activity patterns, with coyotes more likely to be active during daylight hours. Overall, raccoons did not appear to exhibit high levels of vigilance. Activity pattern results provided further evidence that raccoons do not appear to fear coyotes, as both species were active at the same time and showed a high degree of overlap (Δ = 0.75) with little evidence of temporal segregation in activity. Thus, our study indicates that nonconsumptive effects of coyotes on raccoons are unlikely, which calls into question the ability of coyotes to initiate strong trophic cascades through some mesocarnivores.

EEG Feature Extraction Using Genetic Programming for the Classification of Mental States

The design of efficient electroencephalogram (EEG) classification systems for the detection of mental states is still an open problem. Such systems can be used to provide assistance to humans in tasks where a certain level of alertness is required, like in surgery or in the operation of heavy machines, among others. In this work, we extend a previous study where a classification system is proposed using a Common Spatial Pattern (CSP) and Linear Discriminant Analysis (LDA) for the classification of two mental states, namely a relaxed and a normal state. Here, we propose an enhanced feature extraction algorithm (Augmented Feature Extraction with Genetic Programming, or +FEGP) that improves upon previous results by employing a Genetic-Programming-based methodology on top of the CSP. The proposed algorithm searches for non-linear transformations that build new features and simplify the classification task. Although the proposed algorithm can be coupled with any classifier, LDA achieves 78.8% accuracy, the best predictive accuracy among tested classifiers, significantly improving upon previously published results on the same real-world dataset.

An Examination of Circadian Impacts on Judgments

Abstract. Many people suffer from insufficient sleep and the adverse effects of sleep deprivation are well documented. Research has shown that people’s judgments can be affected by circadian timing. Across three studies, we examined the impact of time-of-day on people’s judgments about hypothetical legal scenarios, hypothesizing that participants responding at a suboptimal time of day (3–5 a.m.) would give higher guilt ratings and be less sensitive to case information (e.g., evidence strength) than participants responding at a more optimal time of day (2–4 p.m.). Although the time-of-day manipulation influenced participants’ self-reported alertness levels, time-of-day did not affect guilt judgments or sensitivity to case information. This research adds to the literature on how extraneous factors may and may not impact probability assessments.

Alertness fluctuations when performing a task modulate cortical evoked responses to transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) has been widely used in human cognitive neuroscience to examine the causal role of distinct cortical areas in perceptual, cognitive and motor functions. However, it is widely acknowledged that the effects of focal cortical stimulation can vary substantially between participants and even from trial to trial within individuals. Recent work from resting state functional magnetic resonance imaging (fMRI) studies has suggested that spontaneous fluctuations in alertness over a testing session can modulate the neural dynamics of cortical processing, even when participants remain awake and responsive to the task at hand. Here we investigated the extent to which spontaneous fluctuations in alertness during wake-to-sleep transition can account for the variability in neurophysiological responses to TMS. We combined single-pulse TMS with neural recording via electroencephalography (EEG) to quantify changes in motor and cortical reactivity with fluctuating levels of alertness defined objectively on the basis of ongoing brain activity. We observed rapid, non-linear changes in TMS-evoked responses with decreasing levels of alertness, even while participants remained responsive in the behavioural task. Specifically, we found that the amplitude of motor evoked potentials peaked during periods of EEG flattening, whereas TMS-evoked potentials increased and remained stable during EEG flattening and the subsequent occurrence of theta ripples that indicate the onset of NREM stage 1 sleep. Our findings suggest a rapid and complex reorganization of active neural networks in response to spontaneous fluctuations of alertness over relatively short periods of behavioural testing during wake-to-sleep transition.

Single-Item Chronotyping (SIC), a method to self-assess diurnal types by using 6 simple charts

Research on individual differences in the fields of chronobiology and chronopsychology mostly focuses on two – morning and evening – chronotypes. However, recent developments in these fields pointed at a possibility to extend chronotypology beyond just two chronotypes. We examined this possibility by implementing the Single-Item Chronotyping (SIC) as a method for self-identification of chronotype among six simple chart options illustrating the daily change in alertness level. Of 2283 survey participants, 2176 (95%) chose one of these options. Only 13% vs. 24% chose morning vs. evening type (a fall vs. a rise of alertness from morning to evening), while the majority of participants chose four other types (with a peak vs. a dip of alertness in the afternoon and with permanently high vs. low alertness levels throughout the day, 15% vs. 18% and 9% vs. 16%, respectively). The same 6 patterns of diurnal variation in sleepiness were yielded by principal component analysis of sleepiness curves. Six chronotypes were also validated against the assessments of sleep timing, excessive daytime sleepiness, and abilities to wake or sleep on demand at different times of the day. We concluded that the study results supported the feasibility of classification with the 6 options provided by the SIC.

Complementary Ca2+ Activity of Sensory Activated and Suppressed Layer 6 Corticothalamic Neurons Reflects Behavioral State

Layer 6 (L6) corticothalamic neurons project to thalamus, where they are thought to regulate sensory information transmission to cortex. However, the activity of these neurons during different behavioral states has not been described. Here, we imaged calcium changes in visual cortex L6 primary corticothalamic neurons with two-photon microscopy in head-fixed mice in response to passive viewing during a range of behavioral states, from locomotion to sleep. In addition to a substantial fraction of quiet neurons, we found sensory-activated and suppressed neurons, comprising two functionally distinct L6 feedback channels. Quiet neurons could be dynamically recruited to one or another functional channel, and the opposite, functional neurons could become quiet under different stimulation conditions or behavior states. The state dependence of neuronal activity was heterogeneous with respect to locomotion or level of alertness, although the average activity was largest during highest vigilance within populations of functional neurons. Interestingly, complementary activity of these distinct populations kept the overall corticothalamic feedback relatively constant during any given behavioral state. Thereby, in addition to sensory and non-sensory information, a constant activity level characteristic of behavioral state is conveyed to thalamus, where it can regulate signal transmission from the periphery to cortex.

Multimorbidity and Critical Care Neurosurgery: Minimizing Major Perioperative Cardiopulmonary Complications.

With increasing prevalence of chronic diseases, multimorbid patients have become commonplace in the neurosurgical intensive care unit (neuro-ICU), offering unique management challenges. By reducing physiological reserve and interacting with one another, chronic comorbidities pose a greatly enhanced risk of major postoperative medical complications, especially cardiopulmonary complications, which ultimately exert a negative impact on neurosurgical outcomes. These premises underscore the importance of perioperative optimization, in turn requiring a thorough preoperative risk stratification, a basic understanding of a multimorbid patient’s deranged physiology and a proper appreciation of the potential of surgery, anesthesia and neurocritical care interventions to exacerbate comorbid pathophysiologies. This knowledge enables neurosurgeons, neuroanesthesiologists and neurointensivists to function with a heightened level of vigilance in the care of these high-risk patients and can inform the perioperative neuro-ICU management with individualized strategies able to minimize the risk of untoward outcomes. This review highlights potential pitfalls in the intra- and postoperative neuro-ICU period, describes common preoperative risk stratification tools and discusses tailored perioperative ICU management strategies in multimorbid neurosurgical patients, with a special focus on approaches geared toward the minimization of postoperative cardiopulmonary complications and unplanned reintubation.

COGNITIVE REACTION TIME PERFORMANCE AND SUBJECTIVE DROWSINESS: A CRITICAL EVALUATION OF THE EFFECT OF WHOLE-BODY VIBRATIONS

It is believed that exposure to whole-body vibration (WBV) may increase seated occupant drowsiness, and seated occupant drowsiness may contribute to vehicular accidents. Previous studies on driver comfort have indicated that long-term exposure to WBV may have an adverse effect on musculoskeletal disorders. However, the effects of WBV on seated occupants’ drowsiness have been less rigorously studied. Thus, this study aims to investigate the association between exposure to WBV and drowsiness level. Laboratory experiments were designed and involved eighteen healthy male volunteers. Volunteers were exposed to random gaussian vibration for 20-minutes with the frequency between 1-15Hz. The transmitted vibration magnitude was adjusted for each volunteer to become 0.2ms-2 for low vibration magnitude and 0.4ms2 for medium vibration magnitude. Volunteers’ vigilance was measured by the Psychomotor Vigilance Task (PVT) before and after the vibration exposure. The analyses revealed a substantial drop in volunteers’ vigilance level after exposure to vibration and the effect was more pronounced in high vibration amplitude 0.4 ms-2. These findings suggested that exposure to vibration even as low as 20-minutes may attribute to the reduction of alertness level.

Human video database for facial feature detection under spectacles with varying alertness levels: a baseline study

The pressing demand for workload along with social media interaction leads to diminished alertness during work hours. Researchers attempted to measure alertness level from various cues like EEG, EOG, video-based eye movement analysis, etc. Among these, video-based eyelid and iris motion tracking gained much attention in recent years. However, most of these implementations are tested on video data of subjects without spectacles. These videos do not pose a challenge for eye detection and tracking. In this work, the authors have designed an experiment to yield a video database of 58 human subjects wearing spectacles and are at different levels of alertness. Along with spectacles, they introduced variation in session, recording frame rate (fps), illumination, and time of the experiment. They carried out an analysis to detect the reliableness of facial and ocular features like yawning and eye-blinks in the context of alertness level detection capability. Also, they observe the influence of spectacles on ocular feature detection performance under spectacles and propose a simple preprocessing step to alleviate the specular reflection problem. Extensive experiments on real-world images demonstrate that the authors’ approach achieves desirable reflection suppression results within minimum execution time compared to the state-of-the-art.

Real-World Effectiveness and Safety of Apremilast in Older Patients with Psoriasis.

Apremilast is a drug recently developed for psoriasis. Few data are available on its use in the elderly. We evaluated the tolerance and effectiveness of apremilast used in daily practice for psoriasis treatment in older patients. We performed a multicenter, retrospective study involving patients aged ≥ 65years who had received apremilast as a psoriasis treatment. Demographic data and details regarding psoriasis and adverse events (AEs) were collected from patient medical records. 135 patients were included (mean age: 73.5years). Treatment was stopped in 74 patients (54.8%) for AEs (n = 43, 56.6%), primary failures (n = 18, 23.4%), and relapses (n = 7, 9.2%). When patients were stratified by age at treatment initiation, the main cause of discontinuation in patients ≥ 75years was AEs, whereas in patients aged 65-74years it was primary failures (28.3%). Sixty-one patients reported AEs, mainly digestive (n = 49). Regarding effectiveness, 45.2% of patients reached PGA 0/1 between 3 and 6months after treatment initiation. One-year apremilast continuation rates were better in the 65-74 and 75-84years subgroups than in the > 85years subgroup (p = 0.01). Apremilast seems to be an effective and safe therapeutic option for psoriasis in the elderly. The main AEs reported by patients did not seem to differ from those reported previously in younger populations. However, AEs were more frequent in patients > 75years old leading to more frequent discontinuation of apremilast compared with younger patients, suggesting a higher level of vigilance is needed in the elderly.

General Model for COVID-19 Spreading With Consideration of Intercity Migration, Insufficient Testing, and Active Intervention: Modeling Study of Pandemic Progression in Japan and the United States.

BackgroundThe coronavirus disease (COVID-19) began to spread in mid-December 2019 from Wuhan, China, to most provinces in China and over 200 other countries through an active travel network. Limited by the ability of the country or city to perform tests, the officially reported number of confirmed cases is expected to be much smaller than the true number of infected cases.ObjectiveThis study aims to develop a new susceptible-exposed-infected-confirmed-removed (SEICR) model for predicting the spreading progression of COVID-19 with consideration of intercity travel and the difference between the number of confirmed cases and actual infected cases, and to apply the model to provide a realistic prediction for the United States and Japan under different scenarios of active intervention.MethodsThe model introduces a new state variable corresponding to the actual number of infected cases, integrates intercity travel data to track the movement of exposed and infected individuals among cities, and allows different levels of active intervention to be considered so that a realistic prediction of the number of infected individuals can be performed. Moreover, the model generates future progression profiles for different levels of intervention by setting the parameters relative to the values found from the data fitting.ResultsBy fitting the model with the data of the COVID-19 infection cases and the intercity travel data for Japan (January 15 to March 20, 2020) and the United States (February 20 to March 20, 2020), model parameters were found and then used to predict the pandemic progression in 47 regions of Japan and 50 states (plus a federal district) in the United States. The model revealed that, as of March 19, 2020, the number of infected individuals in Japan and the United States could be 20-fold and 5-fold as many as the number of confirmed cases, respectively. The results showed that, without tightening the implementation of active intervention, Japan and the United States will see about 6.55% and 18.2% of the population eventually infected, respectively, and with a drastic 10-fold elevated active intervention, the number of people eventually infected can be reduced by up to 95% in Japan and 70% in the United States.ConclusionsThe new SEICR model has revealed the effectiveness of active intervention for controlling the spread of COVID-19. Stepping up active intervention would be more effective for Japan, and raising the level of public vigilance in maintaining personal hygiene and social distancing is comparatively more important for the United States.

The critically ill brain after cardiac arrest.

Cardiac arrest can cause hypoxic-anoxic ischemic brain injury due to signaling cascades that lead to damaged cell membranes and vital cellular organelles, resulting in cell death in the setting of low or no oxygen. Some brain areas are more prone to damage than others, so patients with hypoxic-anoxic ischemic brain injury present with several outcomes, including reduced level of consciousness or alertness, memory deficits, uncoordinated movements, and seizures. Some patients may have mild deficits, while others may have such severe injury that it can progress to brain death. High-quality cardiopulmonary resuscitation is a proven technique to improve outcome after cardiac arrest, although morbidity and mortality remain high. Induced hypothermia, which involves artificially cooling the body immediately after cardiac arrest, may reduce injury to the brain and improve morbidity and mortality. Neuroprognostication after cardiac arrest is challenging and requires a multimodal approach involving clinical neurologic examinations, brain imaging, electrical studies to assess brain activity, and biomarkers to predict outcome.