Perceptual Motor Deficits in Space (PMDIS) will investigate why astronauts experience difficulty with hand-eye coordination while on orbit. These measurements will be used to distinguish between three possible explanations: the brain not adapting to the near weightlessness of space; the difficulty of performing fine movements when floating in space; and stress due to factors such as space sickness and sleep deprivation. This experiment is a cooperative effort with the Canadian Space Agency.Principal Investigator(s)
Bristol Aerospace Limited, Winnipeg, Manitoba, Canada
Canadian Space Agency (CSA), Ottawa, Ontario, Canada
Canadian Space Agency (CSA)Sponsoring Organization
Information PendingResearch Benefits
Information PendingISS Expedition Duration:
September 2006 - October 2007Expeditions Assigned
14,15Previous ISS Missions
PMDIS is a new experiment for microgravity research.
Perceptual-Motor Deficits in Space (PMDIS) monitors the hand-eye coordination of astronauts in microgravity. PMDIS will measure the Shuttle astronaut's hand-eye coordination prior to docking with ISS (transition from 1-g to zero-g). Measurements will be taken while the astronaut's arm is securely supported or floating free in three conditions:
A mini-centrifuge with daily sessions has been suggested as a means for countering the physiological effects of long-term space flight, e.g., a Mars mission. This raises the possibility of continual changes in eye-hand coordination as the gravity signal changes on a daily basis. Understanding the cause of coordination loss is therefore critical to developing countermeasures.Earth Applications
Understanding how the brain adapts to physiological changes that the ISS crewmembers undergo will be applicable on Earth as well as space. The results from this experiment will give insight on how the brain overcomes stresses that are not normally part of the day-to-day life. This new information can be applied in many areas of research that deal with neurological diseases in order to provide improved treatments.
The PMDIS apparatus consists of a laptop computer with accessories. For the PMDIS measurements by the Shuttle's crew, the accessories include a joystick, a stylus and touchscreen, a pair of GFE-provided headphones for audio stimuli, and a Hand Reaction Switch box through which the astronaut responds to audio and visual stimuli. This experiment will have scheduling constraints. The crew may not exercise within 20 minutes before the session begins. The session must take place on the Shuttle Middeck.Operational Protocols
During the PMDIS sessions, the crew will be seated on the middeck floor of the Space Shuttle, securely attach with a waist belt. Using a joystick connected to a laptop computer, the astronaut will move a display cursor between two targets. In other trials, the astronaut will tap targets on a touchscreen using a stylus. Also, the astronaut will listen to musical tones and press a button in response while hitting the targets to simulate multi-tasking.
In some early space experiments a loss of hand-eye coordination that could last for 2 to 3 weeks was observed in crewmembers. These losses were attributed to the absence of gravity interfering with normal brain activity. However, later experiments turned up little evidence in support of this so-called microgravity hypothesis. To test this hypothesis directly, the Perceptual Motor Deficits in Space (PMDIS) investigation was conducted with 5 ISS crewmembers on Expeditions 14 and 15 (September 2006 - October 2007). Crew participants practiced performing the experiment prior to actual data gathering to establish stable baseline performance. Data were collected at 30 days preflight, 71 to 94 hours after launch, and 30 days postflight. Testing consisted of aiming at targets on a computer screen with a stylus or a joystick and with the wrist either restrained or unrestrained. These aiming tasks were also performed in conjunction with auditory reaction time as a mentally demanding dual task. Both the speed and accuracy of movement were used to measure performance.
The results from PMDIS contradict the microgravity hypothesis because a major prediction of this hypothesis, that performance would be degraded using either the stylus or the joystick, was not supported. Rather, performance degradation only occurred with the more mentally demanding dual task using the joystick. These results suggest that the loss of hand-eye coordination in space can be attributed to a variety of interacting stressors which lead to cognitive overload. These factors include lack of body stability, degree of learning on the task and its complexity, space sickness, and sleep deprivation.
Thus impairment in hand-eye coordination is not a necessary condition of space flight. Understanding the link between sensory-motor degradation and mental and physical stressors plus how much cognitive resources are required to maintain performance in microgravity is important to developing mitigating strategies through appropriate training, task assignment, and equipment design, especially for future exploration-class missions (Fowler 2008).
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Fowler B, Comfort D, Bock O. A review of cognitive and perceptual-motor performance in space. Aviation, Space, and Environmental Medicine. 2000; 71(Suppl 9): A66-68.
Fowler B, Bock O, Comfort D. Is dual-task performance necessarily impaired in space?. Human Factors. 2000; 42: 318-326.
Fowler B, Manzey D. Summary of research issues in monitoring of mental and perceptual-motor performance and stress in space. Aviation, Space, and Environmental Medicine. 2000; 71 Suppl 9: A76-77.