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April 2012www.sname.org/sname/mt the meaning of the word displayed. The resulting data was stored on the laptop, backed up and transferred to the analysts at the end of each experiment. EEG Recordings. EEG recordings measure the electrical activity of the brain, through several electrodes that are attached to the subjects head. Specialists tted partici- pants with these on two occasions during the week. is occurred on the second and sixth days, and the participants wore them for a complete 24-hour period, thus wear- ing them for two watches and for two rest periods. e data recorded for the o -watch periods is particularly valuable, as it pro- vides an objective picture of exactly when the participant was falling asleep and the quality of that sleep. e data also enables the analysis for micro sleeps during periods of watchkeeping, and this aspect will form an important part of the nal results and ndings from the project. One other test was conducted at the end of each watch when participants were wear- ing the electrodes. is was the Karolinska Drowsiness Test, and it requires partici- pants to stare at a black spot on the wall for ve minutes before closing their eyes for a further five minutes. During this period, the EEG is recording brain activity, and the length of time before a participant starts to fall asleep with eyes closed is an important objective measure of the real state of tired- ness at that time. Fatigue and performance results e results of the study are currently being nalized, so detailed data cannot be pro- vided here. However, the following general points can be made. r e data supports previous research nd- ings and circadian theory. Watchkeepers are most tired during the night watches and also show signs of tiredness in the afternoon. r Sleepiness and neurobehavioral per- formance, as measured by the EEG electrodes, are particularly affected towards the end of the 0000-0600 watch. Sleepiness and fatigue are enhanced and brain performance is reduced. r Some incidents of small periods of sleep have also been shown through analysis of the EEG recordings, both on the bridge and in the engine room. In addition, there is a gradual increase of fatigue during the work periods as the week progresses. r From the evidence of the sleep diaries, the 6 hours on/6 hours o watch regime is more tiring than the 4 on/8 o . r e onset of tiredness on the 6 on/6 o regime was apparent over a shorter time- frame than might have been predicted by previous research. r Disturbed? rest periods produce sig- nicantly higher levels of tiredness; the quality of sleep is more signicant than the workload. r e data appears to be robust enough to provide input to future marine-validated fatigue prediction models. is nal point is an important one. It is hoped that Horizon, in addition to pro- viding guidance to individual seafarers and managers on ensuring good quality sleep, will be able to make a major contribution to the welfare of seafarers by contributing data to the production of fatigue predic- tio n software. Such technology will help seafarers to plan their work schedules and disturbances to the normal watchkeeping patterns in such a way as to mitigate the risk of fatigue. Mike Barnett is associate director (research) at Warsash Maritime Academy in Hampshire in the United Kingdom. Further Reading For more information on the Horizon research study, go to www.warsashacademy.co.uk/ research/horizon/publications.aspx One of the test participants works in the liquid cargo handling simulator. PHOTO BY BRANIMIR PANTALEEV. Warsash Maritime Academy used its newest bridge simulator, produced by Kongsberg, for these experiments.