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Sleep Research Process Test human performance through use of DoD- sanctioned modeling tools and validated sleep testing methods to provide: – cognitive effectiveness levels of crew – watch schedule effects on performance – support for decision-makers on impact of work- rest schedules and policy
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Overview of Study Levels and Options Sleep and Performance field testing can occur at four levels: 1.Observational – non-invasive consultation using predictive models to determine schedule adequacy 2.Investigative – shipboard data collection resulting in recommendations based on actual crew performance 3.Before-After – shipboard data collection, comparing the implementation of a new schedule to an old baseline schedule 4.Retrospective – surveys on watch schedule preferences after the command has explored and implemented various options.
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Observational Study Process Minimal information provided from command and SMEs –Command work-rest schedules –Daytime sleep and activity policy FAST Plots created to determine predicted performance Alternative schedules created in FAST based on same parameters Recommendations provided to command: –Schedule and how to implement –Sleep Knowledge 3
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Investigative Study Process Sleep and performance data collection on current state at command (1-2 weeks) –Surveys – demographics, sleep history and preferences, and other things that affect sleep quality or could influence quality of life –Sleep data collection – wear watches that record motion which we can use to determine sleep duration and quality. Also fill out a sleep-activity log to determine work-rest schedules –Performance data collection – watches have a reaction time test (PVT) that can be taken before/after work periods. –End of study surveys – survey on preferences Alternative schedules created in FAST based on same parameters as seen in actual data Recommendations provided based on actual crew performance. 4
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Before-After Study Process Same data collection procedures as in the investigative process, but implemented twice on same crew: –On current state (traditional schedule) –On newly implemented schedule Comparison analysis conducted to see if the new schedule has any effect on sleep duration and performance. Additional data collection may be applied after 6 months of implementation to determine long-term effectiveness. Recommendations provided based on actual crew performance. 5
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Retrospective Study Process Surveys (paper or electronic) give to the crew to determine schedule preference after command has explored and implemented various options FAST Plots created to determine predicted performance Alternative schedules created in FAST based on same parameters Recommendations provided to command: –Schedule and how to implement –Sleep Knowledge 6
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How to use FAST Tool Based on the SAFTE Model, the FAST tool predicts human performance based on fatigue levels as determined by sleep achieved and circadian desynchronization. Accounts for: –Homeostatic process –Sleep inertia –Time of day –Sleep-wake patterns Accurately predicts performance within a xxx margin of error on PVT task during sleep restriction in a laboratory setting (Belenky et al., 2003) Large error rate for individual predictions experiencing large or chronic sleep restrictions. Download free for military (insert link and email POC). (Eddy & Hursh, 2006)
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50 65 80 95 110 0T1T2B1234567R1R2R3 Day Mean Speed on Psychomotor Vigilance Task (as a % of Baseline) 9 Hr 7 Hr 5 Hr 3 Hr SAFTE/FAST R 2 = 0.94 Recovery 7 Day Restricted Sleep Baseline (Belenky et al., 2003) WRAIR Restricted Sleep Study: PVT Adaptation to Chronic Sleep Restriction 8
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Explanation of FAST Scores A study done on Federal railroad workers showed a significant relationship between FAST predicted effectiveness scores and accidents (Hursh, Raslear et al., 2006). Accident risk is inversely related to FAST predicted effectiveness scores on the left vertical axis. Human factors-related accidents were 65% more likely to occur with FAST scores of 50 or less. FAST scores below 70 were associated with increased fatigue- related errors. SAFTE/FAST also predicted an increase in accident severity. Human factors accidents that occurred when average effectiveness was less than 77.5 were 2 ½ times more costly than similar accidents that occurred when effectiveness was greater than 90. 9
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How to use FAST Tool First the pattern of activity has to be established and recorded in the schedule grid or event log. Insert work and sleep intervals for time period of interest. 10 Schedule Grid– 8 hour shift, restricted sleep Sleep Interval Sleep Interval Sleep Interval Day Shift Evening Shift Mids Shift
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FAST Assumptions Sleep Quality – four sleep ratings based on average assumed number of interruptions and interferences to sleep based on environment. “Excellent Sleep” quality ratings used for normal bedtime hours in shore- based commands where individuals have personal residences “Good Sleep” quality ratings used for normal bedtime hours in operational environments (non-installation based commands where shared space or motion is a factor) “Good Sleep” or “Fair Sleep” quality ratings applied for naps during the day depending on command type and sleeping arrangements “Poor Sleep” quality rating used only in situations of extreme predicted disturbances (i.e. storms at sea, high motion vessels/vehicles, etc.). Use consecutive sleep during circadian night when possible, averaging 7 hours for duty periods and 8 hours on days off (when applicable). Minimum of one hour is allotted between sleep and watch (accounts for transit & turnover) Minimum of 30 minutes is allotted between watch and rest Work intervals based on inputs from the command. 11
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Interpreting FAST Output Afternoon dips in performance Normal sleep periods Reduced sleep period Drop in performance 24 hour period Early AM dip in performance Blood Alcohol Equivalent Scale
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Interpreting FAST Output Green Zone: The green zone on the graph (100% to 90%) is the range of performance during a normal daytime duty day following an eight-hour period of excellent sleep at night. Yellow Zone: The yellow zone (90% to 65%) is the range of performance during the 24 hr period after missing one night of sleep. While difficult to avoid dropping into this zone during the early morning hours (midnight to 0400), naps and other countermeasures are recommended to keep performance in the top half of the yellow zone, above the heavy dashed criterion line. Performance in the yellow zone below the criterion line represents the performance of a person following loss of an entire night's sleep. Red Zone: The red zone (below 65%) indicates performance that is below the level that is acceptable for operations. The red zone represents performance following sleep deprivation of two full days and one night. Reaction time in the Red Zone is more than twice as long as a normal reaction time. The dotted line indicates the Predicted Effectiveness Criterion Line of 77.5. Effectiveness below 77.5 represents the performance of a person during the day following the loss of an entire night’s sleep. 13
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How to use FAST Tool - Example Schedule Grid– 8 hour shift, restricted sleep Sleep Interval Sleep Interval Sleep Interval Day Shift Evening Shift Mids Shift Average PE during Work: 80% Average Below BAC Criterion: 29% Lowest point: 39%
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How to Take the Electronic Survey Survey will be taken on the internet through the Lime Survey site (DoD-authorized secure survey application) Upon consent (maybe), open up the link that will be emailed to you at your command email address Survey will take approximately 15-min to complete Make sure you accurately record your participant ID number in the survey. This ID number is found on your test package and on you sleep watch Once complete, the survey will be sent anonymously to the NPS research team for analysis
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How to use a Sleep Watch We primarily use the Ambulatory Monitoring Inc. (AMI) Motionlogger (picture) Place on non-dominant wrist Face should have local time, a battery life symbol, and a motion indicator present Watch has a skin sensor and records when on/off wrist Three buttons (pictured) Includes a PVT task 1-Mode 2 3
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How to use the PVT 3-minute PVT Task –Ensure you have time to take the test, and will have no distractions (i.e. things that will require your attention). –Push the “Mode” button on the lower right and scroll until “rESP” appears on the watchface –When ready to commence, push “Mode” button again –Keep your finger on the button throughout the test for quick reaction –Push the button as quickly as possible when the watch shows the stimulus or “PUSH” –The watch face will display your response time and then continue with the test for 3-minutes –If you do not respond for a full minute, the test will shut off –Take the test before and after your watch standing period
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How to use a Sleep Log 18
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How to use a Sleep Log 19 This additional information helps us understand and interpret what we are seeing in the watch data Record your sleep and activities according to the log codes on a daily basis “Notes” section: record any unusual things –Example: maybe they had a restless night sleep, or there was an emergency in the middle of the night that awoke them, or they were sea-sick that day, etc. –Can also note information about any distractions that may have occurred during a PVT test.
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