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1.
Sci Rep ; 14(1): 10844, 2024 05 13.
Article in English | MEDLINE | ID: mdl-38735987

ABSTRACT

The rail industry in Australia screens workers for probable obstructive sleep apnea (OSA) due to known safety risks. However, existing criteria to trigger screening only identify a small proportion of workers with OSA. The current study sought to examine the relationship between OSA risk and rail incidents in real-world data from Australian train drivers, and conducted a proof of concept analysis to determine whether more conservative screening criteria are justified. Health assessment (2016-2018) and subsequent rail incident data (2016-2020) were collected from two passenger rail service providers. Predictors included OSA status (confirmed no OSA with a sleep study, controlled OSA, unknown OSA [no recorded sleep assessment data] and confirmed OSA with no indication of treatment); OSA risk according to the current Standard, and OSA risk according to more conservative clinical markers (BMI threshold and cardiometabolic burden). Coded rail safety incidents involving the train driver were included. Data were analysed using zero-inflated negative binomial models to account for over-dispersion with high 0 counts, and rail safety incidents are reported using Incidence Risk Ratios (IRRs). A total of 751 train drivers, typically middle-aged, overweight to obese and mostly men, were included in analyses. There were 43 (5.7%) drivers with confirmed OSA, 62 (8.2%) with controlled OSA, 13 (1.7%) with confirmed no OSA and 633 (84.4%) drivers with unknown OSA. Of the 633 train drivers with unknown OSA status, 21 (3.3%) met 'at risk' criteria for OSA according to the Standard, and incidents were 61% greater (IRR: 1.61, 95% Confidence Interval (CI) 1.02-2.56) in the years following their health assessment compared to drivers who did not meet 'at risk' criteria. A more conservative OSA risk status using lower BMI threshold and cardiometabolic burden identified an additional 30 'at risk' train drivers who had 46% greater incidents compared to drivers who did not meet risk criteria (IRR (95% CI) 1.46 (1.00-2.13)). Our more conservative OSA risk criteria identified more workers, with greater prospective incidents. These findings suggest that existing validated tools could be considered in future iterations of the Standard in order to more sensitively screen for OSA.


Subject(s)
Sleep Apnea, Obstructive , Humans , Sleep Apnea, Obstructive/epidemiology , Sleep Apnea, Obstructive/diagnosis , Male , Female , Middle Aged , Australia/epidemiology , Adult , Mass Screening/methods , Railroads , Incidence , Risk Factors , Risk Assessment/methods , Occupational Health
2.
J Environ Manage ; 357: 120717, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38579466

ABSTRACT

Household food waste is increasingly recognised as a global wicked problem for its greenhouse gas emissions, economic damage, and resource loss. Although targeted in the UN's Sustainable Development Goals, countries can only respond according to their capacity. For Australia, national policy has put the pressure on states and territories to divert food waste away from landfill into a nascent circular economy. For councils, this increasingly means implementing a FOGO (Food Organics/Garden Organics) kerbside collection. Despite funding and infrastructure development, many are resisting. Framed by the tenets of policy diffusion, this paper presents the results of a nationwide exploratory survey aimed at identifying how and why council-based waste services staff resist, emulate or lead FOGO implementation. By assessing participants current kerbside systems and their attitudes towards household food waste management, the survey found costs, contamination, and capacity and were key concerns. However, responses to these varied considerably despite similarities of situation, often relating more to collaborative attitudes across waste services, council, and councillors. This paper recognises that a conducive environment for change is urgently needed for Australia to achieve organics diversion targets and shift household food towards a circular economy. It provides a starting point for further research into the complex and nuanced dynamics between council waste services and FOGO implementations, from external drivers and council paradigms to individual attitudes and perceptions.


Subject(s)
Refuse Disposal , Waste Management , Humans , Refuse Disposal/methods , Food Loss and Waste , Food , Friction , Waste Management/methods , Australia , Policy
3.
Ergonomics ; 67(1): 34-49, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37052461

ABSTRACT

The rail system relies on the effective coordination of multiple disciplines and teams situated within an operational hierarchy to meet a single operational objective-the safe and timely movement of rail traffic. Power and status dispersals across these teams and the various roles within them impact interaction and communication. This study drew on the perceptions of network controllers, to identify organisational factors influencing power imbalances that generate authority gradients between network controllers and other team members. Network controllers (N = 55) across eight Australasian organisations engaged in interviews using the Scenario Invention Task Technique to explore perceptions of risk. Thematic analysis revealed relationships between teams were affected by: (1) the accountability mechanisms adopted by organisations; (2) the way power was vested in roles; and (3) the status attached to roles. This insight into organisational power hierarchies and the generation of authority gradients provides opportunities for understanding teamwork error.Practitioner summary: Communication is impaired by authority gradients across teams in rail and is a contributing factor in incidents occurring on the network. This paper explores the organisational influences on power hierarchies across teams from the perspective of the network controller, pointing to an adversarial culture, resulting in tribalism impeding team interactions.


Subject(s)
Group Processes , Patient Care Team , Humans
4.
Ergonomics ; 66(2): 153-166, 2023 Feb.
Article in English | MEDLINE | ID: mdl-35443875

ABSTRACT

This study aimed to assess occupational health professionals' application of the Goldilocks Work Paradigm in redesigning jobs for healthier physical behaviours while maintaining productivity. During a group simulation exercise, participants (n = 16) created job descriptions for four different occupation cases (factory worker, office worker, teacher, train driver) and then redesigned the jobs using the Paradigm. Substantial changes in the time spent in sitting (9-30%), standing (8-42%), walking (6-14%), and high-intensity (0-24%) physical behaviours were achieved, which if implemented would likely result in enhanced health for workers. Overall, occupational health professionals were able to successfully redesign fictitious jobs aligned with the Goldilocks Work Paradigm. The simulation task used in this study may be useful to train professionals and assist workplaces to understand and implement the Goldilocks Work Paradigm into practice.Practitioner summary: This study assessed whether occupational health professionals could be trained in the Goldilocks Work Paradigm through a job redesign simulation task. Participants were able to redesign jobs to achieve a healthier 'just right' balance of physical behaviours. Simulations may help workplaces understand and implement a Goldilocks Work approach into practice.


Subject(s)
Occupational Health , Humans , Workplace , Occupations , Sitting Position , Standing Position
5.
Appl Ergon ; 106: 103840, 2023 Jan.
Article in English | MEDLINE | ID: mdl-35964429

ABSTRACT

It is not just a rail driver but a "system" that drives a train and network controllers apply non-technical skills to facilitate their role as part of a team. However, because of siloed and distributed working, scenarios exist where network controllers may inadvertently increase operational safety risks. The aim of this study was to generate a better understanding of non-technical skill application in network controllers by identifying which skills and behaviours were associated with problematic ways of working, and which abilities were used to address error-producing scenarios, and thereby reduce risk. Use of a scenario technique and behavioural markers analysis of 61 scenarios generated from 55 network controllers in 8 organisations across Australia and New Zealand revealed a large and diverse application of non-technical skills. Careful consideration must be given to the way in which deficiencies in abilities and skills are addressed. Future research directions are given.


Subject(s)
Safety , Task Performance and Analysis , Humans , Australia , New Zealand
6.
Appl Ergon ; 105: 103806, 2022 Nov.
Article in English | MEDLINE | ID: mdl-35772288

ABSTRACT

Excessive physical demand at work has traditionally been connected with adverse health outcomes, but excessive sitting is now also being recognised as an occupational hazard and emerging work-related risk. Traditional preventive occupational health and ergonomics programs are useful but limited through reliance on individual behaviour change and time-diversion from productive work. A new 'Goldilocks Work Paradigm' aims to optimise health and productivity by using movements of productive tasks. Using rail driving as a specific case of a highly sedentary and inflexible working environment, we construct a conceptual framework for designing better jobs, arguing that a theoretical amalgamation of the new Goldilocks Work Paradigm with System Thinking, Participatory Ergonomics, and a Risk Management Framework, is needed, for establishing a unified, strategic approach-a 'just right' job design model. We extend this by outlining a practical process of designing better jobs with tools that can be used to achieve it.

7.
Sci Rep ; 12(1): 3956, 2022 03 10.
Article in English | MEDLINE | ID: mdl-35273197

ABSTRACT

Train drivers work long hours on 24 h schedules and many factors impact their fatigue risk at work, creating a clear imperative for good rostering practice. Adopting a systems approach, this study investigated the relationship between multiple interrelated factors (train drivers' schedule, sleep, wellbeing, and fatigue) and the perceived influence of these factors on train driving performance and safety using an online survey distributed in Australia and New Zealand. In addition to demographics and work schedule, passenger and freight train drivers (n = 751) answered questions about: (1) Sleep duration; (2) wellbeing, including physical and mental health, the extent to which shiftwork causes sleep, social, domestic, and work problems, and (3) the extent to which ten fatigue, health and wellbeing factors in the work and home environment negatively impact their driving performance. The key factor that emerged from analyses, with the largest and most consistent negative effects (and controlling for other factors) was schedule irregularity. Approved rosters were ranked as having the most important impact on day-to-day driving performance, followed by physical and mental health, and outside work factors. Results also suggested that schedule irregularity may amplify the negative impacts of the roster, impaired physical and mental health, and outside work factors on driving performance. As shift variability and schedule irregularity are often poorly represented in existing industry guidance, these results provide evidence for increased reflection on current fatigue management guidelines for train drivers and suggest a need for greater focus on schedule irregularity through the lens of a systems approach.


Subject(s)
Automobile Driving , Work Schedule Tolerance , Australia , Fatigue/etiology , Humans , New Zealand , Sleep
8.
Hum Factors ; 64(1): 109-125, 2022 02.
Article in English | MEDLINE | ID: mdl-33908808

ABSTRACT

OBJECTIVE: The strategies adopted by personal care attendants (PCAs) to deliver quality care when faced with challenges potentially impacting clinical outcomes were assessed using phenomenological methods. BACKGROUND: In Australia, recent outcry of unsatisfactory standards of care in residential facilities has instigated a national public inquiry. This study investigated how PCAs adapted to challenges in stressful and ambiguous everyday work scenarios to deliver quality care. METHOD: A phenomenological approach was used to obtain insights into PCAs' experiences, perceptions, opinions, and decision processes for enacting care. Ten PCAs working in rural-based residential aged care were interviewed using a novel scenario construction task with thematic and co-occurrence network mapping applied to derive insights. RESULTS: Seven themes were identified, revealing that participants formed close relationships with residents, influencing care provision but blurring personal boundaries. Key contextual factors in scenarios highlighted inadequate staffing and procedures, inadequate training, challenging residents, time poverty, and low support. Individually directed adaptive strategies were used to alleviate dissonance and maintain emotional resilience, including dynamic risk assessment involving rule breaking. CONCLUSION: The findings suggest that in negotiating care delivery, PCAs strive to optimize rule-based compliance with safety, efficiency, and individualized attention to provide "good enough" care with fluidity. Implications for policy and practice are considered. APPLICATION: Findings have implications for workforce development in the context of ever-increasing industry pressures. Findings identified challenging scenarios and role complexity, with decision-making occurring as a fluid and ongoing process across a flexible boundary of risk assessment influencing interactions between PCAs, registered nurses, and clients.


Subject(s)
Delivery of Health Care , Quality of Health Care , Aged , Australia , Humans , Qualitative Research , Workforce
9.
Appl Ergon ; 100: 103644, 2022 Apr.
Article in English | MEDLINE | ID: mdl-34883454

ABSTRACT

Tram driving is a safety critical task where work-related musculoskeletal disorders (WRMSDs) and injuries are associated with interacting occupational design factors over time. These interactions then carry implications for workforce retention, public safety, workplace relations and supports. To better understand such interactions, this study used thematic networks and system dynamics (causal loop diagrams) analysis with the aim to unearth a global theme underscoring occurrence of WRMSDs, and describe the factors influencing the system dynamics of WRMSD occurrence in tram drivers. Building on earlier work focused on occupational participation, secondary analysis of driver interviews (n = 13) and driving observations (n = 11) produced thematic network and causal loop models of risk factors that highlighted an Injury by Design problem structure as a global theme. Research targeting organisational culture, human factors, and design standards is needed to minimise WRMSDs risk in tram drivers.


Subject(s)
Automobile Driving , Musculoskeletal Diseases , Humans , Motor Vehicles , Musculoskeletal Diseases/etiology , Systems Analysis , Workplace
10.
Accid Anal Prev ; 163: 106432, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34710780

ABSTRACT

Collisions between road users and trains at urban railway level crossings persist, despite active protection. The number of railway level crossings in most settings render their removal unfeasible. To effectively reduce or manage risk, alternative treatments are required. Increases in road and rail traffic invariably result in congestion issues at urban railway level crossings, which influences non-compliances by road users. Automated enforcement is one form of treatment that is being considered to reduce such non-compliances. This study conceptualised and adopted a before-after design to evaluate the effect of a conspicuous monitoring system on non-compliances by vehicular road users at an active level crossing. Baseline measurements of vehicle movements and level crossing status were recorded for two months. Conspicuous cameras and radar were subsequently installed, and a further month of data was recorded. Non-compliances with flashing lights were extracted and arranged into "must stop" and "should stop if safe to do so" categories, aligning with road rules at traffic lights. Non-compliances frequently occurred (N = 1,086) with most (94%) of the latter category and ascribed to a lack of an advanced warning before crossing closure. Analysis with Generalised Linear Models revealed that non-compliances where drivers must stop reduced by 36% (from 13.4% to 8.6%) following the introduction of a conspicuous automated monitoring system, even though no actual enforcement was performed. This study suggests that non-compliances at railway level crossings have the potential to be reduced through the introduction of automated enforcement similar to the one used at traffic lights.


Subject(s)
Automobile Driving , Railroads , Accidents, Traffic/prevention & control , Humans
11.
Appl Ergon ; 95: 103433, 2021 Sep.
Article in English | MEDLINE | ID: mdl-33989951

ABSTRACT

The road environment has changed markedly over the years. Train horns are ostensibly used to alert road users and are typically mandatory on approach to railway level crossings. However, they have increasingly been seen as a nuisance. Beyond their negative aspects, a study has yet to comprehensively evaluate train horn effectiveness and understand if they remain beneficial and relevant in the contemporary environment. Hence, this study aimed to provide evidence on the actual use of train horns. Field observations were conducted at 54 railway crossings across four Australian States. The effects of level crossing type, location, and environmental conditions were investigated in relation to train horn loudness as objectively measured at the crossing. Results revealed that train horns were not always used, presenting an issue for passive level crossings. However, when sounded, train horn use was redundant and insufficiently loud at level crossings equipped with bells. Taken together, current train horn practice was found to be highly variable and dependent on crossing type, remoteness, and individual train drivers, thus resulting in inconsistent warnings and raising important implications for standardisation.


Subject(s)
Automobile Driving , Railroads , Accidents, Traffic , Australia , Humans
12.
Hum Factors Ergon Manuf ; 31(4): 438-444, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33821127

ABSTRACT

The rail industry, as with all sectors worldwide, has faced disruptions due to the global COVID-19 pandemic. This commentary considers how rail organizations in Australia have engaged within the early stages of the crisis, outlining the challenges faced and how they were addressed. Relying on our observations, and anecdotes obtained from others across the Australian rail industry, we identified a range of impacts including determining service delivery levels (and the associated running of "ghost trains"), implementing hygiene measures and social distancing, managing training and medical assessments, and changes in the behavior of passengers and members of the public (including aggression toward staff and increased instances of trespass). Within rail organizations, we saw changes to communication and control structures, new challenges related to balancing priorities (managing risk of rail accidents vs. virus transmission risk), and negative impacts on job design offset by increased informal support for frontline workers. Importantly, from the crisis, we gained new insights about culture. Finally, we provide recommendations regarding how the Human Factors and Ergonomics discipline can support safe and effective rail operations in the context of both widespread crises such as pandemics as well as the less dramatic, but ever present, shifts in the physical, social, economic, and political environments in which rail organizations operate.

13.
Disabil Rehabil ; 43(16): 2253-2267, 2021 08.
Article in English | MEDLINE | ID: mdl-31800337

ABSTRACT

PURPOSE: Being able to access public transport is vital for mobility device users as this is an affordable way of maintaining community connections and participating in activities that promote quality of life. This systematic review investigated literature on public transport access for people using mobility devices, excluding transit restraint and securement literature. MATERIALS AND METHODS: A systematic review of the peer-reviewed literature in English from 1995 to 2019, with critical appraisal and narrative synthesis. RESULTS: Twenty-six articles were identified, including 14 studies investigating user experiences, seven examining bus formats and floor layouts, and five focusing on bus ramp incidents and optimal design. Studies were generally observational and descriptive, with 12 including analysis of video data. CONCLUSION: This is the first systematic review of literature related to the accessibility of public transport for people using mobility devices. Topics such as ramp access have been relatively well-researched, as have the experiences of users. However, many gaps remain and there is a need for research to; address the barriers identified through user experiences, discern the best access to stations and stops, as well as floor formats for people to ingress, manoeuvre and egress from a variety of transport modes, and promote universal design principles in the transport sector. Rehabilitation professionals can use the findings of this review to advocate for, and support people using mobility devices to successfully negotiate public transport.Implications for RehabilitationAccessible public transport is vital to enable people using mobility devices to remain connected in their communities.Despite increased international awareness and adoption of accessibility features by the public transport sector to improve getting to a stop, ingress, manoeuvrability within and egress from conveyances, access for people using wheeled mobility devices cannot be assumed.When prescribing new wheeled mobility devices with clients, rehabilitation professionals and users need to consider public transport access and the suitability of different devices for this purpose.Rehabilitation professionals can undertake skills training with people using wheeled mobility devices to test out access prior to independent travel on public transport and develop strategies to overcome any barriers.


Subject(s)
Self-Help Devices , Wheelchairs , Architectural Accessibility , Humans , Quality of Life , Transportation
14.
Simul Healthc ; 16(1): 60-66, 2021 Feb 01.
Article in English | MEDLINE | ID: mdl-32371748

ABSTRACT

SUMMARY STATEMENT: Although a focus on the learner rightly remains in any teaching environment, the psychological safety of everyone involved in the conduct of experiential learning and critical academic scholarship is important. Education literature suggests that faculty are just as prone to psychological harm as their learners. This commentary describes adverse experiences from a simulation-based education event that took place at an Australasian interprofessional and cross-domain simulation workshop. Event facilitators explored the notion of the "safe container" but, in the process, were themselves exposed to psychological injury. We summarize an ostensibly complex simulation activity with unintended sequelae, the ethical concerns surrounding the faculty care, and from lessons learned, present an extended conceptualization of the safe container including broader parameters around the preparation of all involved in the delivery of simulation-based activities. Our goals in sharing this case is to encourage the community to become more vigilant regarding the unintended consequences of our simulation activities and to encourage open reporting and discussion of such incidents for the betterment of the field.


Subject(s)
Faculty , Fellowships and Scholarships , Humans
15.
Appl Ergon ; 82: 102976, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31630068

ABSTRACT

Signal passed at danger (SPAD) events have been a perennial issue in rail and requires continued scholarship. Much of the literature has tended to focus on activities within the train cab, placing the spotlight on "error" within the rail driving role; however a train is not propelled by a single person but by a team. This study set out to understand how network controllers perceive the relationship dynamic between the network controller and rail driver, and how these views shape system performance. Using a phenomenological approach underpinned by Joint Cognitive Systems theory, interviews were conducted with network controllers (N = 55) across 8 rail organisations in Australia and New Zealand to examine how they related to signals and to drivers. Sixteen different perspectives were identified ranging in type and varying by frequency, each with implications for coupling strength between the controller and driver roles and on system performance. Key dimensions of teamwork in train movement were emphasised, illustrating how the underlying values and philosophies in different network controlling cultures influence risk perception. The findings may be used to develop a more informed understanding of the 'controller-signal-driver-train' system and pave the way for strategies that can embrace diversity in different perspectives whilst optimizing system safety and performance.


Subject(s)
Accident Prevention/methods , Cooperative Behavior , Mental Processes , Railroads , Task Performance and Analysis , Ergonomics , Humans , Models, Theoretical , Visual Perception
16.
Ind Health ; 57(6): 691-700, 2019 Nov 29.
Article in English | MEDLINE | ID: mdl-30842353

ABSTRACT

Cardiovascular disease (CVD) risk in train drivers is associated with health conditions that can result in sudden incapacity. Drivers are at high risk on several CVD risk factors with research suggesting that sleep may predict CVD risk, however this relationship has not yet been explored. This study investigated the link between sleep and CVD risk, in relation to hours of work day and days off sleep. N=309 Australian drivers completed a cross-sectional survey. A CVD risk score was calculated by summing scores from behavioural and biomedical risk factors. Sleep was most frequently cited as the main reason for decline in perceived health status. Main analyses showed that shorter work day sleep (M=5.79 h) was a significant predictor of increased CVD risk (p=0.013). This relationship was moderated by days off sleep, such that when days off sleep (M=8.17 h) was higher, the effect of work day sleep on CVD risk was weaker (p=0.047). Findings indicate the amount of sleep a driver obtains on non-work days may compensate for adverse health outcomes. Successful management of fatigue in safety critical occupations appears essential not only for the prevention of safety hazards, but also for the long-term health of shift workers. Further investigation is warranted.


Subject(s)
Cardiovascular Diseases/epidemiology , Sleep/physiology , Work Schedule Tolerance , Adult , Australia , Cross-Sectional Studies , Humans , Male , Middle Aged , Railroads , Risk Factors , Surveys and Questionnaires
17.
Disabil Rehabil Assist Technol ; 14(2): 122-132, 2019 02.
Article in English | MEDLINE | ID: mdl-29183207

ABSTRACT

PURPOSE: The number of mobility aid users continues to rise as the population ages. While mobility aid users rely on public transport due to its affordability, evidence suggests access can be difficult. This study aims to describe people who use mobility aids to access public transport and the role of public transport access in influencing mobility aid choice. METHODS: Sixty-seven mobility aid users participated in telephone surveys which predominantly used a structured quantitative format. Data were analysed descriptively and any additional comments were simply categorized. RESULTS: Thirty-six participants were female (54%), with a total sample mean age of 58.15 years (SD = 14.46). Seventy-two percent lived in metropolitan areas, 48% lived alone, and the sample experienced a variety of conditions including spinal cord injury (37%) and arthritis (18%). Sixty-four percent of all respondents used two or more mobility aids including powered wheelchairs, scooters and walking frames. The most important features when choosing a mobility aid were reliability, turning ability and size. Fifty-two percent of all respondents strongly agreed that public transport is generally accessible. CONCLUSIONS: While work continues to ensure that public transport vehicles and stations are fully accessible, mobility aid users must manage current infrastructure and access a system which has been shown through this research to have many limitations. Mobility aid users, vendors and health professionals need to work together to identify mobility aids that fulfil needs, and are reliable and safe, so that mobility aid users are both "visible and seen" when accessing the public transport network. Implications for rehabilitation Some mobility aid users experience difficulties accessing and using public transport and further research is required to ensure the whole public transport network is fully accessible to people using mobility aids. Many people have more than one seated mobility aid, suggesting people can choose different aids for different purposes and environments. Health professionals may need to increase their involvement in assisting individuals to select and use mobility aids.


Subject(s)
Choice Behavior , Disabled Persons , Self-Help Devices , Transportation , Architectural Accessibility , Female , Humans , Male , Middle Aged , Mobility Limitation , Surveys and Questionnaires , Wheelchairs
18.
Ergonomics ; 62(1): 115-127, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30265217

ABSTRACT

Verbal protocol analysis (VPA) is often used to elicit information about the cognitive processes of operators as it provides rich data and can be used in naturalistic settings. Recently VPA has been used to investigate the acquisition and maintenance of situation awareness (SA), and to make comparisons between groups despite a lack of research regarding the efficacy of using VPA for this purpose. This train simulator experiment investigated whether VPA can effectively measure SA. Novice and expert participants were recorded on an audio device while talking aloud throughout the trials and their verbalisations were transcribed verbatim. A coding scheme developed from the transcripts was used to code the verbalisations. Results did not support the use of VPA as a measure of SA but did show that VPA detected differences in SA errors. Potential reasons for the conflicting findings between this experiment and those conducted by other researchers are discussed. Practitioner summary: This paper examined the validity of verbal protocol analysis (VPA) as a situation awareness (SA) measure. A repeated measures experiment was conducted using a train simulator. Normal VPA did not detect changes in SA but a measure of errors did. Caution should be used when using VPA to measure SA. Abbreviations: LETSSA: low-event task subjective situation awareness technique; SA: situation awareness; SAGAT: situation awareness global assessment technique; TPD: train performance display; VPA: verbal protocol analysis.


Subject(s)
Automobile Driving/psychology , Awareness , Ergonomics/methods , Narration , Adult , Aged , Computer Simulation , Female , Humans , Male , Mental Competency/psychology , Middle Aged , Railroads , Reproducibility of Results , Task Performance and Analysis , Young Adult
19.
Ergonomics ; : 1-4, 2018 Nov 20.
Article in English | MEDLINE | ID: mdl-30457488
20.
Chronobiol Int ; 35(6): 872-883, 2018 06.
Article in English | MEDLINE | ID: mdl-29889574

ABSTRACT

Some shiftwokers in the long-haul transportation industries (i.e. road, rail, sea, air) have the opportunity to sleep in on-board rest facilities during duty periods. These rest facilities are typically fitted with a seat with a maximum back angle to the vertical of 20°, 40°, or 90°. The aim of this study was to examine the impact of "back angle" on the quantity and quality of sleep obtained in a seat during a daytime nap. Six healthy adults (3 females aged 27.0 years and 3 males aged 22.7 years) each participated in three conditions. For each condition, participants had a 4-h sleep opportunity in a bed (02:00-06:00 h) followed by a 4-h sleep opportunity in a seat (13:00-17:00 h). The only difference between conditions was in the back angle of the seat to the vertical during the seat-based sleep periods: 20° (upright), 40° (reclined), and 90° (flat). Polysomnographic data were collected during all sleep episodes. For the seat-based sleep episodes, there was a significant effect of back angle on three of four measures of sleep quantity, i.e. total sleep time, slow-wave sleep, and rapid eye movement (REM) sleep, and three of four measures of sleep quality, i.e. latency to REM sleep, arousals, and stage shifts. In general, the quantity and quality of sleep obtained in the reclined and flat seats were better than those obtained in the upright seat. In particular, compared to the flat seat, the reclined seat resulted in similar amounts of total sleep and slow-wave sleep, but 37% less REM sleep; and the upright seat resulted in 29% less total sleep, 30% less slow-wave sleep, and 79% less REM sleep. There are two main mechanisms that may explain the results. First, it is difficult to maintain the head in a comfortable position for sleep when sitting upright, and this is likely exacerbated during REM sleep, when muscle tone is very low. Second, an upright posture increases sympathetic activity and decreases parasympathetic activity, resulting in a heightened level of physiological arousal.


Subject(s)
Circadian Rhythm/physiology , Posture/physiology , Rest/physiology , Sleep/physiology , Adult , Arousal/physiology , Female , Head/physiology , Humans , Male , Young Adult
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