Influence of Gravity on the Size-mass Illusion (Massper)

Parabolic flight is the only ground-based condition in which free-fall (0G) can be created long enough for safely testing changes in human perception and behavior. In addition to the 0G period, parabolic flight generates equal duration periods of 1.8G, which present another unique opportunity to test the same responses to hypergravity and back to 1G.

It is well known that performance decrements occur in astronauts during and after gravity level transitions. Illusions are commonly felt in orbit as well disorientation and perceptual limitations, mainly due to both psycho-physiological changes and adaptation and lack of familiar points of reference in the space environment. Studies performed during previous space missions showed several changes occurring in different gravity conditions, pointing out, for example, that colors and shadows were misleading, the depth and distance perception were weakened, and the linear perspective was lost. Visual perception is of primary importance for spatial orientation and object recognition because the static vestibular (otolithic) and proprioceptive signals are absent when free-floating. Consequently, astronauts become increasingly dependent on vision to perceive motion and orientation. All these factors play an important role in the adaptation of humans to spaceflight that needs to be analyzed to understand the underlying mechanisms that regulate human psycho-physiological adaptive process to changing gravity. Human psycho-physiological health has to be safeguarded and possibly improved when long-term human space missions are programmed in the near future.

The primary objective of this experiment is to investigate if the SWI illusion is present in altered gravity environments. Since weight cannot be estimated in 0G, investigators have developed a procedure during which the subject is asked to estimate the objects' mass by shaking them rather than lifting them. Our results in 1G indicate that a size-mass illusion (SMI) is also present in 1G. Our hypothesis is that the previously observed alteration in 3D visual perception in 0G, particularly in the height of 3D objects, as well as the change in proprioceptive inputs, will be responsible for changes in the SMI in 0G and 1.8G compared to 1G. In a separate proposal, investigators will also propose to perform this experiment using the ESA short-arm human centrifuge (SAHC), with subjects exposed to various centrifugal force levels, to further investigate the role of proprioceptive cues in the size-mass illusion.

Study Overview

• Status: Unknown
• Conditions: Healthy
• Intervention / Treatment: Other: parabolic flight; Other: mass/weight perception estimation; Device: ESA short-arm human centrifuge (SAHC)

• Study Type: Interventional
• Enrollment (Anticipated): 36
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Basse-Normandie
    • Caen CEDEX, Basse-Normandie, France, 14032
      • Recruiting
      • Umr Ucbn/Inserm U1075 Comete

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Healthy volunteers (men or women)
• Aged from 21 to 65
• Right handed
• Affiliated to a Social Security system and, for non-French resident, holding a European Health Insurance Card (EHIC)
• Who accepted to take part in the study
• Who have given their written stated consent
• Who has passed a medical examination similar to a standard aviation medical examination for private pilot aptitude (JAR FCL3 Class 2 medical examination). There will be no additional test performed for subject selection.

Exclusion Criteria:

• Person who took part in a previous biomedical research protocol, of which exclusion period is not terminated
• Pregnant women

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Influence of Gravity on the Size-mass Illusion; to investigate the interaction between perceived size and perceived mass of objects in 0G and 1.8G compared to 1G using the size-mass illusion (SMI)	Other: parabolic flight; Other: mass/weight perception estimation; estimate the mass/weight perception, expressed by verbally report the absolute and relative mass of the object using a scale from 1 to 10 (1 being light and 10 being heavy); Device: ESA short-arm human centrifuge (SAHC)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
perceived size and perceived mass of objects in 0G and 1.8G compared to 1G using the size-mass illusion (SMI) (composite)	baseline

Collaborators and Investigators

• Sponsor: University Hospital, Caen

Study record dates

Study Major Dates

• Study Start: October 1, 2013
• Primary Completion (Anticipated): October 1, 2016

Study Registration Dates

• First Submitted: July 22, 2015
• First Submitted That Met QC Criteria: July 23, 2015
• First Posted (Estimate): July 24, 2015

Study Record Updates

• Last Update Posted (Estimate): July 24, 2015
• Last Update Submitted That Met QC Criteria: July 23, 2015
• Last Verified: July 1, 2015

More Information

Terms related to this study

• Keywords: volunteers
• Other Study ID Numbers: 13-028