11 Apr 2017

Volunteers are going to bed to help human spaceflight research. This ‘bedrest participant’ is performing the Grasp experiment at the Medes Space Clinic in Toulouse, France. Developed by France’s CNES space agency, Grasp investigates if – and how – gravity affects hand–eye coordination.
Bedrest studies are a low-cost method of studying the effects of weightlessness on the human body. Participants spend up to 60 days in bed with the head end tilted 6° below horizontal. By monitoring changes and learning why they occur, researchers learn and develop solutions for problems faced by astronauts in space as well as bedridden patients on Earth.

Grasp is being run on bedrest patients to understand how the brain reaches and grasps in altered gravity. Volunteers are spending two months in bed – one shoulder must be in contact with the bed at all times – while researchers study how the brain adapts to this head–body misalignment and whether new strategies develop to compensate for the downward tilt.
Equipped with a virtual reality headset, the subjects react to scenarios requiring them to reach and grasp for an object while motion sensors record their movements.

The assumption is that on Earth, in addition to visual cues, the brain uses gravity as a reference frame for coordinating hand movement. How then does the brain adapt to altered states of gravity or even the lack of it? Answers to this question will allow researchers to better understand the physiology behind hand–eye coordination and to shed light on how to treat patients with vertigo, spatial disorientation and other vestibular disorders.
ESA astronaut Thomas Pesquet, who is spending six months on the International Space Station on his Proxima mission, will set up the experiment for future astronauts. The space version of Grasp will investigate the effects of a total lack of gravity cues on sensory-motor performance.