|
Principal Investigator:
|
Charles M. Oman, Ph.D.
|
|
Organization:
|
Massachusetts Institute of Technology
|
Although robotic operations during spaceflight have been successful, there have been a few incidents in which fatigue has been identified as a probable contributing factor. Astronauts are often so busy, they sleep much less than eight hours per night, and sometimes have to dramatically change their sleep schedules. Dr. Charles Oman is leading a team of researchers at MIT and the Brigham & Women's Hospital in a project to validate countermeasures and tests used in the detection and reduction of human performance changes during robotic operations.
The researchers will study the performance of subjects performing robotic tasks in a laboratory setting while following typical astronaut sleep schedules. The project's first objective is to understand how fatigue affects various aspects of robotic operator performance. Another goal is to validate several widely used neurobehavioral performance tests including the Psychomotor Vigilance Test (PVT) as predictors of robotics task performance. The third goal is to test the ability of countermeasures – including caffeine and blue-enriched light – to maintain or improve performance.
|
Principal Investigator:
|
Charles M. Oman, Ph.D.
|
|
Organization:
|
Massachusetts Institute of Technology
|
In this project, subjects are trained to perform simulated robotics tasks under realistic astronaut schedules. Using a within-subjects design, our experiments will investigate how the proposed fatigue countermeasures affect both cognitive and task performance, thereby enabling their relationship to be understood. If this correlation can be established, we will provide more evidence that these assessment tools could be used as indicators of fitness-for-duty.
Specific Aims
1. Characterize the changes in cognitive function during robotic operations that affect performance
2. Validate proxy cognitive assessment tests such as the Spaceflight Cognitive Assessment Tool for Windows (WinSCAT) or Psychomotor Vigilance Test (PVT) as predictors of performance changes in a complex operational task
3. Test the efficacy of fatigue countermeasures (e.g., light, caffeine, modafinil) to improve cognition during robotic operations
To date, the complex robotics operations aboard the shuttle and International Space Station have been successful, but not entirely without incident. The impairment of cognitive abilities, likely due to fatigue, has been identified as a factor leading to errors in performance. In nominal operations, pauses, unnecessary movements and performance inefficiency may reflect cognitive impairment. Preventative countermeasures are necessary to reduce this risk and improve crew safety for current and future robotic operations.
The project is a collaborative effort between the MIT Man Vehicle Laboratory, the Division of Sleep Medicine at Brigham and Women's Hospital (BWH) and Harvard Medical School, the NASA Johnson Space Center Mechanical and Robotics Systems Group, and the NASA Astronaut Office. Subjects are trained to perform simulated robotics tasks under realistic astronaut schedules. Using a within-subjects design, our experiments investigate how the proposed fatigue countermeasures affect physiologic, cognitive and task performance metrics, thereby enabling their relationship to be understood. If this correlation can be established, it will provide evidence that these metrics could be valuable as indicators of fitness-for-duty.
Subjects are initially consented, screened for robotics aptitude and medical factors, and then follow a normal sleep schedule (8hr/night) for two to three weeks and receive further robotics training. Robotics task include a variety of simulated ISS fly-to/grapple, autosequence, and track-and-capture tasks. Subjects then shift to a restricted sleep schedule 6 hr/night for one week before admission to the sleep clinic for the inpatient phase of the study, and undergo a refresher training session. The inpatient study design consists of four three-day-long experiment blocks. In each block, subjects take a three-hour nap late on the first day. On the second day they are awoken nine hours early - a "slam shift" of their sleep schedule - and their performance on robotics, concurrent mental workload (imbedded visual response time task), cognitive (Number-Letter, Digit Symbol Substitution), and psychomotor (10 min PVT) tasks is evaluated during a six-hour robotics session. They will have been awake for 18 hours by the end of the robotics session. Subjects are allowed eight hours of recovery sleep on the third day, on the preadmission schedule. Physiological measures (plasma melatonin and cortisol, EEG, Optalert eyelid opening speed) and subjective sleepiness (KSS) and alertness measures are taken throughout. The first three-day block is used as a control: subjects are tested using 90 lux white light. In subsequent blocks, subjects are tested under three conditions with order randomized across subjects: a) 90 lux blue-enriched white light, b) 90 lux white light and hourly caffeine (0.3 mg/kg), and c) 90 lux blue-enriched light and caffeine. The blue-enriched light stimulus is provided by a Solid State Lighting Module developed for ISS.
So far, 18 of 24 planned subjects have completed the inpatient study or are in process, and initial data analysis is underway. As described below, this year MIT also completed two pilot studies: The first confirmed that subject spatial ability scores of our inpatient experiment subjects predicted performance during initial robotics screening by MIT trainers blind to their spatial ability scores. The second, conducted on MIT student volunteers, demonstrated that imbedded visual secondary tasks are sensitive to 18 vs. four hours awake, even though subjects were apparently able to maintain their performance on the relatively challenging primary robotics task while sleepy. Findings suggest that a decrement in spare attention may be an early sign of drowsiness when performing demanding robotics tasks.
|
Principal Investigator:
|
Charles M. Oman, Ph.D.
|
|
Organization:
|
Massachusetts Institute of Technology
|
An effective, safe, well-tolerated, noninvasive countermeasure for circadian and fatigue-related deficits in cognition is required for use during in-space environments to enhance the safety of crew members. Light exposure has the potential to fulfill this role. Although monochromatic blue light exposure at night has been shown to be most effective at shifting the circadian pacemaker and improving alertness and performance, these results have not been tested for broadband blue-enriched white light or for light exposure during the biological day. Before light therapy as a fatigue countermeasure is operationalized, further research is required to fully understand its effect on complex performance, such as robotics performance.
Similarly, while caffeine use is widespread, including on the International Space Station, uncontrolled use of caffeine may not be optimally timed or of the correct dose to alleviate sleepiness on duty. The result may interfere with subsequent sleep, thereby increasing fatigue the next day. The current study will investigate the effects of light and caffeine as fatigue countermeasures in a controlled environment with the long-term view of developing specialized countermeasure schedules to maximize alertness and performance of space crew in an environment where even a small fatigue-related error could have catastrophic consequences.
These results will also have widespread application on Earth. Approximately 18,000 Air Force pilots and flight crew are exposed to conflicting circadian signals and resulting fatigue from long flights. Tens of thousands of troops are subjected to rapid deployment worldwide and are often required to maintain alertness while suffering from jet lag. Additionally, nearly 180,000 troops are required to be vigilant for more than 24 hours at a time, and thousands of U.S. Navy and Coast Guard personnel work for extended periods under circadian misalignment. Over 200,000 commercial airline pilots, flight crews and air traffic controllers are also subjected to extended shifts and circadian misalignment. More than 230,000 emergency room doctors, staff and medical residents work extended shifts for 30 hours or more. Approximately 1.9 million public safety personnel (police, corrections officers, firefighters, etc.), work extended shifts and are exposed to emergencies which require vigilance for long periods. In total, more than 3 million Americans would directly benefit from the findings of this research.
In addition, applications may be possible in standard occupational settings to improve general daytime alertness such as in educational settings (e.g., training sessions and conferences, colleges, and schools where enhanced alertness would assist learning and memory). Benefits from this research could also be seen as a fatigue countermeasure for sleepy car and truck drivers in order to provide them with a short burst of alertness that will allow them to find a safe place to stop driving and take a break. These wider applications have the potential to reach tens of millions of customers and anyone who could benefit from improved alertness and performance.
Print