Fatigue and alertness in the United States railroad industry part I: the nature of the problem

The railroad industry must actively manage employee fatigue and alertness problems to maintain an optimal level of operational safety and productivity. Given the necessity to operate nights and irregular hours, weekends and holidays under a wide range of physical conditions and service demands, we must explore every reasonable avenue to ensure employees are fit, alert, and well-rested. Effective fatigue management programs must address train crews, dispatchers, signalmen, track workers, and others – both operating and non-operating personnel. Work scheduling is a particular problem in on-call operations because of start-time variability, “call” predictability, and the common use of “shorter-than 24-h work/rest schedules”. Extensive night operations are incompatible with normal circadian rhythms. Staffing limitations often require extensive overtime and reduce the effectiveness of any work schedule. These and other institutional factors significantly contribute to employee sleep deficit and overall fatigue. Lack of alertness and reduced vigilance are related not only to sleep disruption and resulting sleep deficits, but also to cognitive workload, workload transition, the physical working environment, and the design of advanced control systems. Ongoing research into fatigue mitigation and alertness enhancement strategies and into advanced technologies such as Positive Train Control (PTC) can lead to improvements. These include better labor–management agreements, more effective fatigue-related educational programs, improved schedule regularity, and more practical and adaptable federal laws and regulations.     

Repetitive Thought and Self-Reported Sleep Disturbance

Repetitive thought has been focused upon as a transdiagnostic risk factor for depression, anxiety, and poor physical health. Among the forms of repetitive thought, rumination and worry are considered to play important roles in the onset and maintenance of insomnia. However, there have been few attempts to clarify the similarities, differences, and interaction between the functions of rumination and worry in sleep problems. Furthermore, no study has investigated the prospective relationships between these two forms of repetitive thought and sleep disturbance. In the present study, we examined the prospective associations between repetitive thought and subjective sleep quality, measured by a self-report questionnaire. A total of 208 undergraduates participated in a 2-wave longitudinal survey with an interval of 3 weeks between assessments. Hierarchical multiple regression analyses showed that baseline rumination predicted reduction in the follow-up assessment of subjective sleep quality, controlling for levels of depressive and anxious symptoms. This main effect of rumination was qualified by the levels of worry; for individuals with higher levels of worry, rumination was associated with greater reduction in subjective sleep quality. These results suggest that both rumination and worry have unique associations with sleep and that their interaction is especially important in sleep problems.     

A Review of Published Self-help Books for Panic Disorder

This brief review of 14 self-help books on panic disorder compares: target group, treatment time, included components, existence of structured exercises, and whether or not daily record-keeping is encouraged. Six of the books cover all components deemed necessary for a multimodal cognitive-behavioral treatment package, and five of these are recommended. The reviews are followed by a brief summary of published bibliotherapy studies in which a selection of the books has been used. The results of these studies suggest that bibliotherapy is effective, with an effect size ranging from d = 0.5 to d = 1.5.     

Sleep duration and chronotype in adults in Côte d'Ivoire: influence of gender,religion and age

This study investigated the sleep-wake rhythm and chronotype of people living in Côte d'Ivoire. We assessed sleep-wake behaviour in 556 adults (336 men, 220 women) between 25 and 54 years (mean: 38.63) by means of structured interviews. Data were analysed by linear models with sleep wake variables as dependent variables and age, gender, religion and region (urban/rural) as fixed factors controlling for number of working hours and children. Results suggest sleep length not to differ between weekdays and weekends but sleep timing (chronotype) was later on weekends with a midpoint of sleep at 1:37am during weekdays compared to 1:58am on weekends. The more children, the earlier was the midpoint of sleep and the shorter was sleep length. Midpoint of sleep was earlier in older people. Women slept longer during weekdays and were earlier chronotypes. Sleep duration was longer in the rural areas and midpoint of sleep was later in the urban areas on weekdays and on the weekend. Muslims showed the shortest sleep duration and were earliest chronotypes. Sleep-wake cycles in the African setting sample were shorter for women, Moslems, and older people.     

Insights into sleep's role for insight: Studies with the number reduction task

In recent years, vibrant research has developed on “consolidation” during sleep: To what extent are newly experienced impressions reprocessed or even restructured during sleep? We used the number reduction task (NRT) to study if and how sleep does not only reiterate new experiences but may even lead to new insights. In the NRT, covert regularities may speed responses. This implicit acquisition of regularities may become explicitly conscious at some point, leading to a qualitative change in behavior which reflects this insight. By applying the NRT at two consecutive sessions separated by an interval, we investigated the role of sleep in this interval for attaining insight at the second session. In the first study, a night of sleep was shown to triple the number of participants attaining insight above the base rate of about 20%. In the second study, this hard core of 20% discoverers differed from other participants in their task-related EEG potentials from the very beginning already. In the third study, the additional role of sleep was specified as an effect of the deep-sleep phase of slow-wave sleep on participants who had implicitly acquired the covert regularity before sleep. It was in these participants that a specific increase of EEG during slow-wave sleep in the 10-12 Hz band was obtained. These results support the view that neuronal memory reprocessing during slow-wave sleep restructures task-related representations in the brain, and that such restructuring promotes the gain of explicit knowledge.     

Editorial to the special issue Neuronus

Did you visit the Neuronus conferences in the years 2012 and 2013 in Kraków? If not, then you certainly should have a close examination of this special issue including this introduction to at least have a glimpse of an idea of the highly interesting topics in the field of cognitive neuroscience that were presented at these conferences. If you were there, it is for sure a good choice to focus on this special issue as well, first to refresh your minds (we know our memories are far from perfect), but especially to see what happened with research of the presenters at these conferences.     

毕生控制理论的新发展:调节模型及控制策略

毕生控制理论能较好地解释毕生发展,认为适应能力的中心特质是动机调节,可促进个体发展并使其达到最优化.生命历程被视为由一列有序的目标定向行动周期组织而成,该周期包括目标选择、目标结合及目标解除.基于该角度,在回顾控制理论的基本概念、初级控制的首要性和毕生发展轨迹基础上,对毕生发展的调节模型和控制策略的适应功能进行了综合阐述.未来研究应从跨文化情境下的适用性、满足适应目标选择三个因素的进一步验证和成功老龄化相关研究等方面开展更深入的探讨.     

睡眠的同步EEG-fMRI研究述评

同步EEG-fMRI利用了脑电和功能磁共振在时空分辨率上的互补优势,为睡眠研究提供了多模态的无创手段.这使得睡眠的神经成像研究可以借助电生理方法进行睡眠分期和特殊脑电事件研究,为探讨不同意识状态下神经活动动态过程提供了条件.本评述从自发脑活动和睡眠中的知觉过程两方面介绍了目前该领域的最新进展,结合硬件构成、被试安全和数据质量等问题总结了同步记录应用于睡眠的优缺点.同步EEG-fMRI技术在睡眠研究中的应用对于阐明意识状态转换的神经机制具有深刻意义,并有可能为临床睡眠障碍的诊断和治疗提供全新的思路.