Developing measures of fatigue using an alcohol comparison to validate the effects of fatigue on performance
ABSTRACT The effects of 28 h of sleep deprivation were compared with varying doses of alcohol up to 0.1% blood alcohol concentration (BAC) in the same subjects. The study was conducted in the laboratory. Twenty long-haul truck drivers and 19 people not employed as professional drivers acted as subjects. Tests were selected that were likely to be affected by fatigue, including simple reaction time, unstable tracking, dual task, Mackworth clock vigilance test, symbol digit coding, visual search, sequential spatial memory and logical reasoning. While performance effects were seen due to alcohol for all tests, sleep deprivation affected performance on most tests, but had no effect on performance on the visual search and logical reasoning tests. Some tests showed evidence of a circadian rhythm effect on performance, in particular, simple reaction time, dual task, Mackworth clock vigilance, and symbol digit coding, but only for response speed and not response accuracy. Drivers were slower but more accurate than controls on the symbol digit test, suggesting that they took a more conservative approach to performance of this test. This study demonstrated which tests are most sensitive to sleep deprivation and fatigue. The study therefore has established a set of tests that can be used in evaluations of fatigue and fatigue countermeasures.
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ABSTRACT: Fatigue in fishing has been a highly underprioritised area of research, even though fatigue has been found to be the largest single contributing factor in accidents. The aim of this article/paper is to provide an overview of the research conducted on fatigue in fishermen up to date, in order to establish a starting point for further research in this area. The review is mainly based on journal articles from PubMed, Google Scholar, International Maritime Health, Science Direct and some relevant articles links were also followed. The research revealed that only 5 articles have been published concerning fatigue in fishermen.The articles all confirmed that fatigue is a serious health and safety issue among fishermen, and that further research therefore is warranted. Only 2 of the 5 studies of fishermen's fatigue used objective measures and in one of these, the sample size was small (n = 19), effectively limiting the statistical analysis and its application. Further research using larger samples is needed, preferably with a mix of objective and subjective measures, where of some of the questions should be scenario based and some should be from standardised questionnaires. Greater understanding is also needed to assess how much of the variance in fatigue is attributable to e.g. length of trip, hours of work without rest, and type of job and specific tasks. A greater understanding of the similarities and differences between acute and long-term fatigue is also needed.International maritime health 09/2014; 65(3):166-72. DOI:10.5603/IMH.2014.0031
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ABSTRACT: Because of their dreamlike character, authors have speculated about the role that the sleep-wake cycle plays in dissociative symptoms. We investigated whether sleep loss fuels dissociative symptoms and undermines cognitive efficiency, particularly memory functioning. Fifty-six healthy undergraduate students were randomly assigned to an experimental group (n = 28) and a control group (n = 28). The experimental group was deprived of sleep for 36 h in a sleep laboratory; the control group had a regular night of sleep. Sleepiness, mood, and dissociative symptoms were assessed 6 times in the experimental group (control group: 4 times). Several cognitive tasks were administered. Sleep deprivation led to an increase in dissociative symptoms, which was mediated by levels of general distress. Feelings of sleepiness preceded an increase of dissociative symptoms and deterioration of mood. Finally, sleep loss also undermined memory of emotional material, especially in highly dissociative individuals. Limitations included moderate reliability of the mood scale, limited generalizability due to student sample, and a relatively short period of intensive sleep deprivation rather than lengthy but intermittent sleep loss, representative of a clinical population. We found that sleep deprivation had significant effects on dissociation, sleepiness, and mood. Specifically, sleepiness and dissociation increased during the night, while mood deteriorated. Our findings stress the importance of sleep deficiencies in the development of dissociative symptoms. They support the view that sleep disruptions fuel distress, but also degrade memory and attentional control. It is against this background that dissociative symptoms may arise. Copyright © 2014. Published by Elsevier Ltd.Journal of Behavior Therapy and Experimental Psychiatry 11/2014; 47C:9-17. DOI:10.1016/j.jbtep.2014.11.002 · 2.23 Impact Factor