The Impact of Sleep Deprivation on the Level of Sleepiness, Fatigue, and Stress on Experiment Using Driving Simulator

Sleep prior to driving has been discussed widely in fatigue driving research focusing on how it affected driver on duty. This study is intended to compare the impact of prior normal sleep hour and sleep reduction during long-duration driving to subjective sleepiness, fatigue and stress level. To aim this objective, within-subject 2 x 2experiments was conducted (4 experiments condition). Sleep hour variable consists of ± 4 hours (var11) and ± 8 hours sleep (var12) before driving, and long duration driving consist of non-stop 5 hours driving (var21) ended with 60 minutes rest, and 2.5 hour driving x 2 sessions (var22) with 30 minutes break between session and ended with 30 minutes rest. Driving task conducted in laboratory started at ± 7 am to ± 1 pm using a simulator that set to highway and city route randomly. Thirteen participants were involved in these four experiments, each of them conducted in a different day in random fashion. Karolinska Sleepiness Scale (KSS/scale 1–9) and Visual Analogue Scale (0–10) were applied to rated subjective sleepiness and fatigue level, and saliva amylase was used to measure the participants’ stress level that was collected using Cocoro meter nipro. The result showed that sleepiness and fatigue level under sleep reduction condition was relatively higher compared to the normal sleep condition, while saliva amylase test result slightly increases after experiments, but cannot becategorized into stress condition yet. The conclusion is a duration and sleep hours before driving factors were induced fatigue, sleepiness and stress to driver, but lack of sleep has a higher impact compare to driving duration. Further research with another profession may give different results. Keywords: driving simulator, fatigue from driving, Karolinska Sleepiness Scale, sleep deprivation, stress leve

Analyzing driver drowsiness: from causes to effects

Drowsiness and fatigue are major safety issues that cannot be measured directly. Their measurements are sustained on indirect parameters such as the effects on driving performance, changes in physiological states, and subjective measures. We divided this study into two distinct lines. First, we wanted to find if any driver's physiological characteristic, habit, or recent event could interfere with the results. Second, we aimed to analyze the effects of subjective sleepiness on driving behavior. On driving simulator experiments, the driver information and driving performance were collected, and responses to the Karolinska Sleepiness Scale (KSS) were compared with these parameters. The results showed that drowsiness increases when the driver has suffered a recent stress situation, has taken medication, or has slept fewer hours. An increasing driving time is also a strong factor in drowsiness development. On the other hand, robustness, smoking habits, being older, and being a man were revealed to be factors that make the participant less prone to getting drowsy. From another point of view, the speed and lane departures increased with the sleepiness feeling. Subjective drowsiness has a great correlation to drivers' personal aspects and the driving behavior. In addition, the KSS shows a great potential to be used as a predictor of drowsiness. (c) 2020 by the authors

Detecting Driver Sleepiness Using Consumer Wearable Devices in Manual and Partial Automated Real-Road Driving

Driver sleepiness constitutes a well-known traffic safety risk. With the introduction of automated driving systems, the chance of getting sleepy and even falling asleep at wheel could increase further. Conventional sleepiness detection methods based on driving performance and behavior may not be available under automated driving. Methods based on physiological measurements such as heart rate variability (HRV) becomes a potential solution under automated driving. However, with reduced task load, HRV could potentially be affected by automated driving. Therefore, it is essential to investigate the influence of automated driving on the relation between HRV and sleepiness. Data from real-road driving experiments with 43 participants were used in this study. Each driver finished four trials with manual and partial automated driving under normal and sleep-deprived condition. Heart rate was monitored by consumer wearable chest bands. Subjective sleepiness based on Karolinska sleepiness scale was reported at five min interval as ground truth. Reduced heart rate and increased overall variability were found in association with severe sleepy episodes. A binary classifier based on the AdaBoost method was developed to classify alert and sleepy episodes. The results indicate that partial automated driving has small impact on the relationship between HRV and sleepiness. The classifier using HRV features reached area under curve (AUC) = 0.76 and it was improved to AUC = 0.88 when adding driving time and day/night information. The results show that commercial wearable heart rate monitor has the potential to become a useful tool to assess driver sleepiness under manual and partial automated driving

Sleepiness and fatigue following traumatic brain injury

Objectives : To compare individuals with traumatic brain injury (TBI) to healthy controls (CTLs) on measures of sleepiness, fatigue, and sleep, and explore correlates of sleepiness and fatigue separately for each group. Methods : Participants were 22 adults with moderate/severe TBI (time since injury ⩾1 year; mean = 53.0 ± 37.1 months) and 22 matched healthy CTLs. They underwent one night of polysomnographic (PSG) recording of their sleep followed the next day by the Maintenance of Wakefulness Test (MWT). They also completed a 14-day sleep diary, the Epworth Sleepiness Scale (ESS), the Functional Outcomes of Sleep Questionnaire (FOSQ), and the Multidimensional Fatigue Inventory (MFI). Results : There were no significant group differences on measures of objective (MWT) or subjective (ESS) sleepiness, both groups being quite alert. However, TBI participants reported greater consequences of sleepiness on their general productivity (FOSQ), spent more time in bed at night, and napped more frequently and for a longer time during the day. Subjective fatigue was significantly higher in TBI participants on the general, physical, and mental fatigue MFI subscales. There were no between-group differences on any sleep parameters derived either from PSG or sleep diary. Conclusions : Fatigue appeared to be a more prominent symptom than sleepiness when assessed between 1 and 11 years after TBI. Participants with TBI used compensatory strategies such as increasing time spent in bed and daytime napping in this sample. Future research should document the time course of sleepiness and fatigue after TBI and investigate treatment options

Brain structural correlates of subjective sleepiness and insomnia symptoms in shift workers

BackgroundStudies on the brain structures of shift workers are limited; thus, this cross-sectional study aimed to compare the brain structures and the brain structural correlates of subjective sleepiness and insomnia symptoms between shift workers and non-shift workers.MethodsShift workers (n = 63) and non-shift workers (n = 58) completed questionnaires assessing subjective sleepiness and insomnia symptoms. Cortical thickness, cortical surface area, and subcortical volumes were measured by magnetic resonance imaging. The brain morphometric measures were compared between the groups, and interaction analyses using the brain morphometric measures as the dependent variable were performed to test the interactions between the study group and measures of sleep disturbance (i.e., subjective sleepiness and insomnia symptoms).ResultsNo differences in cortical thickness, cortical surface area, or subcortical volumes were detected between shift workers and non-shift workers. A single cluster in the left motor cortex showed a significant interaction between the study group and subjective sleepiness in the cortical surface area. The correlation between the left motor cortex surface area and the subjective sleepiness level was negative in shift workers and positive in non-shift workers. Significant interaction between the study group and insomnia symptoms was present for the left/right putamen volumes. The correlation between the left/right putamen volumes and insomnia symptom levels was positive in shift workers and negative in non-shift workers.ConclusionLeft motor cortex surface area and bilateral putamen volumes were unique structural correlates of subjective sleepiness and insomnia symptoms in shift workers, respectively

Blue-Enriched Light Enhances Alertness but Impairs Accurate Performance in Evening Chronotypes Driving in the Morning

Attention maintenance is highly demanding and typically leads to vigilance decrement along time on task. Therefore, performance in tasks involving vigilance maintenance for long periods, such as driving, tends to deteriorate over time. Cognitive performance has been demonstrated to fluctuate over 24 h of the day (known as circadian oscillations), thus showing peaks and troughs depending on the time of day (leading to optimal and suboptimal times of day, respectively). Consequently, vigilance decrements are more pronounced along time on task when it is performed at suboptimal times of day. According to research, light exposure (especially blue-enriched white) enhances alertness. Thus, it has been proposed to prevent the vigilance decrement under such adverse circumstances. We aimed to explore the effects of blue-enriched white light (vs. dim light) on the performance of a simulated driving task at a suboptimal time of day. A group of evening-types was tested at 8 am, as this chronotype had previously shown their largest vigilance decrement at that time. In the dim light condition, vigilance decrements were expected on both subjective (as increments in the Karolinska Sleepiness Scale scores) and behavioral measures [as slower reaction times (RTs) in the auditory Psychomotor Vigilance Task, slower RTs to unexpected events during driving, and deteriorated driving accuracy along time on task]. Physiological activation was expected to decrease (as indexed by an increase of the distal-proximal temperature gradient, DPG). Under blue-enriched white light, all these trends should be attenuated. Results from the control dim light condition replicated the vigilance decrement in all measures. Most important, the blue-enriched white light attenuated this decrement, leading to both lower DPG and faster RTs. However, it impaired accuracy of driving performance, and did not have any effect on subjective sleepiness. We conclude that exposure to blue-enriched light provides an effective countermeasure to enhance vigilance performance at suboptimal times of day, according to measures such as RTs. However, it should be considered that alerting effects of light could impair accuracy in precision tasks as keeping a proper car position. The current findings provide ergonomic implications for safety and fatigue related management systems.This work was supported by the Spanish and Andalusian Governments to ÁC (MINECO: PSI2014-58041-P, and Proyectos de Excelencia JJAA: SEJ-3054) and to JM (MINECO: SAF2013- 49132-C2-1-R)

Observing changes in human functioning during induced sleep deficiency and recovery periods

Prolonged periods of sleep restriction seem to be common in the contemporary world. Sleep loss causes perturbations of circadian rhythmicity and degradation of waking alertness as reflected in attention, cognitive efficiency and memory. Understanding whether and how the human brain recovers from chronic sleep loss is important not only from a scientific but also from a public health perspective. In this work we report on behavioral, motor, and neurophysiological correlates of sleep loss in healthy adults in an unprecedented study conducted in natural conditions and comprising 21 consecutive days divided into periods of 4 days of regular life (a baseline), 10 days of chronic partial sleep restriction (30% reduction relative to individual sleep need) and 7 days of recovery. Throughout the whole experiment we continuously measured the spontaneous locomotor activity by means of actigraphy with 1-minute resolution. On a daily basis the subjects were undergoing EEG measurements (64-electrodes with 500 Hz sampling frequency): resting state with eyes open and closed (8 minutes long each) followed by Stroop task lasting 22 minutes. Altogether we analyzed actigraphy (distributions of rest and activity durations), behavioral measures (reaction times and accuracy from Stroop task) and EEG (amplitudes, latencies and scalp maps of event-related potentials from Stroop task and power spectra from resting states). We observed unanimous deterioration in all the measures during sleep restriction. Further results indicate that a week of recovery subsequent to prolonged periods of sleep restriction is insufficient to recover fully. Only one measure (mean reaction time in Stroop task) reverted to baseline values, while the others did not.Fil: Ochab, Jeremi K.. Jagiellonian University. Marian Smoluchowski Institute of Physics; Polonia. Jagiellonian University. Mark Kac Complex Systems Research Centre; PoloniaFil: Szwed, Jerzy. Jagiellonian University. Marian Smoluchowski Institute of Physics; Polonia. Jagiellonian University. Mark Kac Complex Systems Research Centre; PoloniaFil: Oles, Katarzyna. Jagiellonian University. Marian Smoluchowski Institute of Physics; PoloniaFil: Beres, Anna. Jagiellonian University. Department of Cognitive Neuroscience and Neuroergonomics; PoloniaFil: Chialvo, Dante Renato. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martin. Escuela de Ciencia y Tecnologia. Centro de Estudios Multidisciplinarios En Sistemas Complejos y Ciencias del Cerebro.; ArgentinaFil: Domagalik, Aleksandra. Jagiellonian University. Department of Cognitive Neuroscience and Neuroergonomics; PoloniaFil: Frafrowicz, Magdalena. Jagiellonian University. Department of Cognitive Neuroscience and Neuroergonomics; PoloniaFil: Oginska, Halszka. Jagiellonian University. Department of Cognitive Neuroscience and Neuroergonomics; PoloniaFil: Gudowska-Nowak, Ewa. Jagiellonian University. Marian Smoluchowski Institute of Physics; Polonia. Jagiellonian University. Małopolska Center of Biotechnology ; PoloniaFil: Marek, Tadeusz. Jagiellonian University. Department of Cognitive Neuroscience and Neuroergonomic; Polonia. Jagiellonian University. Małopolska Center of Biotechnology; ArgentinaFil: Nowak, Maciej A.. Jagiellonian University. Marian Smoluchowski Institute of Physics; Polonia. Jagiellonian University. Mark Kac Complex Systems Research Centre; Poloni

Electronic Image Detectability under Varying Illumination Conditions

Light in the built environment plays an essential role in the vision and the health of humans through non-visual receptors in the eyes. Unfortunately, image analysts and other Air Force personnel who engage in the detection of objects on softcopy displays are often required to work in very dimly-lit or dark environments as higher illumination reduces the contrast of displayed information. Literature has shown that increases in light exposure improves circadian rhythm entrainment and reduces the negative health consequences of insufficient lighting. This research examines the effects of indoor lighting to determine if increases in ambient illumination or changes to the orientation of light fixtures improves or degrades alertness and visual performance. Positive findings of this study would lead to changes in the environment of image analysts, increasing productivity and long-term health. In a controlled environment, twelve participants were exposed to D65 ambient light at levels of 0, 21, 32, and 43 lux, through overhead lighting, wall-washing, and under-desk illumination orientations. During exposures, participants were asked to visually identify variations in low-contrast Gabor patches on a display. The data was used to calculate the contrast threshold of detectability and response times of participants, thus indicating visual performance. Surveys also measured the subjective alertness and discomfort of participants. Results showed that the orientation of light fixtures significantly affects participant sleepiness, weariness, and discomfort. Additionally, the results indicate that visual detection performance is improved with higher ambient illumination levels employed within this research

Effects of light interventions for adaptation to night work : Simulated night work experiments

In modern society, the need for 24-hr operation and services requires some people to work outside normal daytime work hours (i.e. shift work), including the night. For instance, healthcare, police, and transportation, are sectors where night work is common. Exposure to shift work, and particularly night work, can have negative impact on the workers’ health. Especially, sleep is reported to be disturbed among night workers, as they must be awake at times they would normally be sleeping, and sleep at times they would normally be awake. This circadian misalignment of the sleep-wake rhythm may in a long-term perspective lead to ill health and diseases. Also, in a short-term perspective night work may cause adverse effects. Night workers experience increased sleepiness and performance deterioration during night shifts, and especially in the early morning hours, the sleep propensity and performance decrements are high. As such, night work has also been associated with increased risk of accidents and injuries. Several countermeasures to reduce the adverse impact of night work have been suggested. Common strategies involve scheduled naps and caffein use. However, there is increasing interest in the use of light interventions for eliciting beneficial effects for night workers. Light exposure has the potential to entrain the biological circadian rhythm in humans, and as such can be used to produce circadian adaptation to a night work schedule. In addition, light has acute alerting effects which can reduce alertness deficits and improve performance during the night shift. Such effects rely on several characteristics of the light, such as timing, intensity, and wavelengths (spectral distribution). With the development of light emitting diode (LED) technology, new strategies for illumination of workplaces have emerged. This thesis is based on three papers using standard ceiling mounted LED-luminaires to administer different light conditions during simulated night shift experiments. The main aim has been to investigate and elucidate how such LED lighting strategies can be used to facilitate adaptation to night work on measures of sleepiness, performance, and circadian rhythm. In paper 1, the objective was to investigate how a full spectrum (4000 K) bright light (~ 900 lx), compared to a standard light (~ 90 lx), affected alertness and performance during three consecutive simulated night shifts (23:00–07:00 hrs), as well as circadian phase shift after the simulated night shifts. Results indicated that bright light effectively reduces sleepiness, and improves performance during three consecutive night shifts, compared to standard light. Bright light seems to be beneficial in the later parts of the shifts, when sleep propensity is particularly high. For instance, in the later parts of night 2 and 3 it was found that the number of lapses of attention on a vigilance task revealed half as many lapses with bright light, compared to standard light. Furthermore, bright light induced a larger phase delay as compared with standard light, although data were incomplete, hence validation of these findings are needed. The objective in the second paper was to investigate how short-wavelength monochromatic blue light (λmax = 455 nm), compared to red light (λmax = 625 nm) with similar photon density (~ 2.8 x 1014 photons/cm2/s), affected alertness and task performance during one simulated night shift (23:00–06:45 hrs), as well as circadian phase shift following the night shift. The results in paper 2 suggest that monochromatic blue light reduces sleepiness and improves performance in the later parts of the night shift. Similar to the findings in paper 1, the number of attentional lapses with blue light was half of that seen with red light. Blue light also led to a larger phase delay of the circadian rhythm. There were indications of improved visual comfort with blue light, although both light conditions overall produced visual discomfort. In the third paper the main aims were to investigate how polychromatic blue-enriched white light (7000 K; ~ 200 lx), compared to warm white light (2500 K) of similar photon density (~ 1.6 x 1014 photons/cm2/s), affected alertness and performance during three consecutive simulated night shifts (23:00–06:45 hrs), as well as circadian adaptation to the night work schedule. The results indicated minor, yet beneficial effects of 7000 K light compared to 2500 K light, mainly in terms of fewer performance errors on a vigilance task in the end of night 1 and 2. No significant difference in terms of circadian phase shifts were found between these two light conditions. In conclusion, the papers suggest that standard ceiling mounted LED-luminaires have the potential to produce light conditions that may facilitate adaptation to night work. Paper 1 suggests that bright light improves performance and reduces sleepiness during three consecutive simulated night shifts. Results from paper 2 indicate that short-wavelength blue light improves performance, reduces sleepiness, and causes a larger phase delay than long-wavelength red light during one simulated night shift. Paper 3 indicates that using polychromatic blue-enriched white light has minor, yet beneficial effects on performance measures, compared to warm white light during three consecutive simulated night shifts. Further research is needed to validate and support the findings and investigate the impact and feasibility of similar light conditions in real-life workplaces. Future research should also explore more light conditions that can be favourable for night workers, in order to develop recommendations for illumination of night workers workplaces. Moreover, there is a need to elucidate potential long-term adverse health impacts of exposure to LED lighting.Doktorgradsavhandlin