Spaceflight may differentially affect gravity and rotation sensors, given the input to the gravity sensor becomes zero but input to the rotation sensor is preserved in space. To examine this, gravity and rotation sensor function will be separately evaluated before and after the ISS mission, and these functions will be correlated to body balance impairment.
These studies are important, because the impaired vestibular system may relate spaceflight-induced medical problems such as gravity sickness, impaired body balance, orthostatic hypotension, and muscle and bone atrophy. To examine mechanisms of spaceflight-induced medical problems, investigators separately evaluate otolith and canal functions, and test whether weak galvanic vestibular stimulation (GVS) can ameliorate an impaired vestibular function. The purpose of the research is to evaluate otolith and canal functions separately and to correlate those functions to body balance impairment. Additionally, the effect of weak-noise-GVS on body balance will be examined.
Baseline data collection will be conducted 4 times: once preflight and three times postflight. All procedures are noninvasive and finished in one hour. To evaluate otolith function, ocular vestibular evoked myogenic potential (oVEMP) and cervical VEMP (cVEMP) will be measured. In these tests, myogenic potentials are measured from the eyelid muscle and the cervical muscle evoked by sound or vibration. To evaluate canal function, air caloric tests will be performed. During this test, eye movements will be recorded, while air of 50ºC and 24ºC are injected from the external auditory canal. To evaluate balance ability, the subject will stand on a balance board for 60 seconds, with or without the eyes open and with or without weak GVS.
Additionally, a Crew Questionnaire related to motion sickness and instability will be completed. Subjective symptoms of motion sickness, dizziness, nausea status, unusual motion and medication usage within 24 hours of each data collection session will be documented.
This experiment is in progress. Results will be available at the conclusion of the study.
|Mission||Launch/Start Date||Landing/End Date||Duration|
|Expedition 54||12/14/2017||02/27/2018||75 days|
|Expedition 55||02/27/2018||06/03/2018||96 days|
|Expedition 56||06/03/2018||10/04/2018||123 days|
|Expedition 57||10/04/2018||In progress|
|Expedition 58||Future mission|
|Expedition 59||Future mission|
|Expedition 60||Future mission|