Kristian Gould

Improving the saccade peak velocity measurement for detecting fatigue.

The aim of the study was to compare saccadic peak velocity (SPV) values measured with video based Fitness Impairment Tester (FIT) and electro-oculography (EOG) during prolonged wakefulness. We tested different numbers of saccades and two saccade paradigms to improve the EOG measurements for detecting fatigue. The SPVs were measured from 11 fast patrol boat navigators with FIT and EOG every sixth hour until 54 h. Subjective sleepiness was assessed with the Karolinska Sleepiness Scale. EOG was measured using an overlap and a gap paradigm and the data was divided into sequential five 20-saccade blocks and cumulative blocks of 20, 40, 60, 80, and 100 saccades. Compared to the gap paradigm, the overlap paradigm produced a higher number of analyzable saccades for a given measurement time. The shorter measurements (20-40 saccades) appeared to be more sensitive for fatigue, whereas the longer measurements (60-100 saccades) were more sensitive to time spent on the task. Thus, the optimal number of saccades varies also depending on the research question. The EOG method was more sensitive to fatigue than FIT. The FIT values measured after 30 and 36 h of wakefulness did not differ significantly from the baseline values, while subjective sleepiness and the EOG values showed that the participants were significantly less alert at these time points. The EOG measurements can be improved for detecting fatigue by using the overlap saccade paradigm. The SPV values measured with the EOG method appear to be somewhat more sensitive in detecting fatigue than the FIT method.

Effects of navigation method on workload and performance in simulated high-speed ship navigation.

This study examines mental workload and performance in simulated high-speed ship navigation. Two navigation methods were compared based on an electronic chart display and information system (ECDIS) and a conventional system using paper charts. Twenty naval cadets navigated in high-fidelity simulators through a 50 nautical mile course with varying levels of difficulty. Results showed that ECDIS navigation significantly improved course-keeping performance, but reduced the total amount of communication on the bridge. No differences were observed in subjective workload between groups. Heart rate variability and skin conductance measurements indicated higher workload in conventional navigation, but the differences between groups were not significant.

Human reliability analysis in major accident risk analyses in the Norwegian petroleum industry

Major accidents in the petroleum industry can have severe consequences for people and the environment, as seen in recent cases such as the Deepwater Horizon. Human factors have been shown to play an important role both in the cause and mitigation of these accidents. However, major accident risk analyses in the oil and gas industry has previously not included assessments of human reliability. As part of our company’s overall safety strategy, we have recently made an effort to apply human reliability assessments in major accident risk analyses of offshore activities such as drilling and production of oil. This paper outlines our strategy for use of human reliability assessment, our experiences from practice, and methodological challenges that must be improved for it to become established in the offshore petroleum industry.

Effects of 60 hours of total sleep deprivation on two methods of high-speed ship navigation

This study investigated how workload and performance in high-speed ship navigation was affected by sleep deprivation using methods based on either paper charts or electronic chart display and information systems (ECDIS). In two separate weeks, five navigators sailed 10 routes in high-fidelity simulators while undergoing progressive sleep deprivation for up to 60 h. Results showed that navigation performance was better using ECDIS, but was largely unaffected by sleep deprivation in both. There was significant interaction between speed, sleep deprivation and navigation method, indicating that navigators using ECDIS reduced their speed more while sleepy. Secondary task performance was reduced by sleep deprivation, but was equally affected in both conditions. Workload was higher in the ECDIS condition, as indicated by subjective ratings and heart rate variability. No significant differences in sleepiness were found, but electroencephalographic recordings indicated more frequent microsleep episodes in the ECDIS condition. This may be influenced by lower overall arousal while navigating with ECDIS.

Performance-shaping factors associated with navigation accidents in the Royal Norwegian Navy

This study examined the presence of performance-shaping factors (PSFs) in investigation reports following 35 navigation accidents in the Royal Norwegian Navy between 1990 and 2005. This was done to provide an overview of the situational factors present at the time of the accidents, which were related to the human, task, system, and environment. PSFs are defined as any factors that influence the likelihood of an error occurring. Factors related to task requirements and individual cognitive characteristics were most common, followed by operational characteristics of the system. Eight PSF clusters were found, indicating a pattern in accident circumstances. Possible measures for improving safety and performance include training, changes in task organization, and improved bridge systems.

Muscle pain, physical activity, self-efficacy and relaxation ability in adolescents

The main aim was to examine the prevalence of neck, shoulder and upper back pain, and evaluate possible associations between such symptoms and physical activity, self-efficacy and relaxation ability in a sample of adolescents. The data come from a cross-sectional field study on 416 Norwegian second-year electrician, hairdresser, art/design and media students from 13 technical schools, 265 females and 151 males. The mean age was 17.5 years. Data was acquired from a questionnaire and clinical examination. More female than male students (28% vs. 15%) reported high pain complaint levels. Females were engaged in less physical activity and obtained lower self-efficacy scores, but demonstrated better relaxation ability than male students. In bivariate analyses, high self-efficacy scores were significantly associated with high levels of physical activity and poor relaxation ability among males. No significant associations were found in multivariate analyses between physical activity, self-efficacy or relaxation ability and pain symptoms in either males or females. Among males, a tendency of increasing pain odds ratios with increasing physical activity level was seen. Follow-up research on this cohort is needed to explore further differences between males and females, and identify factors associated with neck, shoulder or upper back pain among these adolescents.

The application of the SPAR-H method in managed-pressure drilling operations

This paper aims to share insights gained in the application of the Standardized Plant Analysis Risk-Human Reliability Analysis (SPAR-H) technique applied to a normal-operations scenario for a managed pressure drilling concept. SPAR-H was used to identify the potential for error for each individual task related to the concept. A Systematic Human Error and Prediction Approach (SHERPA) was performed to gain more insight into the qualitative aspects of the operation including the potential consequences for safety should a task be performed erroneously. For this project, the relative Human Error Probabilities (HEP) values of SPAR-H were used rather than HEPs as absolute performance indicators. With this approach, an evaluation of the concept was performed in terms of its potential for human error and a prioritized set of improvements for the concept was presented. Such application of SPAR-H was found to be a useful approach to aiding project managers in directing focus towards those issues that require most attention.

Contrast sensitivity and the effect of 60-hour sleep deprivation

The study aimed to evaluate the possible influence of prolonged sleep deprivation on achromatic and chromatic (red–green and blue–yellow) contrast sensitivity (CS).

Saccadic eye movements estimate prolonged time awake

Prolonged time awake increases the need to sleep. Sleep pressure increases sleepiness, impairs human alertness and performance and increases the probability of human errors and accidents. Human performance and alertness during waking hours are influenced by homeostatic sleep drive and the circadian rhythm. Cognitive functions, especially attentional ones, are vulnerable to circadian rhythm and increasing sleep drive. A reliable, objective and practical metrics for estimating sleepiness could therefore be valuable. Our aim is to study whether saccades measured with electro‐oculography (EOG) outside the laboratory could be used to estimate the overall time awake without sleep of a person. The number of executed saccades was measured in 11 participants during an 8‐min saccade task. The saccades were recorded outside the laboratory (Naval Academy, Bergen) using EOG every sixth hour until 54 hr of time awake. Measurements were carried out on two occasions separated by 10 weeks. Five participants participated in both measurement weeks. The number of saccades decreased during sustained wakefulness. The data correlated with the three‐process model of alertness; performance differed between participants but was stable within individual participants. A mathematically monotonous relation between performance in the saccade task and time awake was seen after removing the circadian rhythm component from measured eye movement data. The results imply that saccades measured with EOG can be used as a time‐awake metric outside the laboratory.