Table 2.
Description of the Oculomotor and Motor Tests Performed Immediately after Space Shuttle and ISS Missions.
| Space Shuttle | ISS | |
|---|---|---|
| Oculomotor tests | Subjects were asked to gaze in various directions or to follow the examiner’s moving finger. Gaze-evoked nystagmus, abnormally slow or fast saccades, asymmetry, and inaccurate tracking were assessed qualitatively by relying on direct observation of the subjects’ eye movements in visible light. Two subjects were examined for signs of positional nystagmus via Frenzel goggles and the Dix-Hallpike maneuver.12 | Subjects were asked to gaze in various directions or to follow the examiner’s moving finger. Gaze-evoked nystagmus was assessed qualitatively by relying on direct observation of the subjects’ eye movements in visible light. |
| Pointing | The examiner raised a finger in front of the subjects and asked them to touch it with their finger and then touch their nose several times. This showed the subjects’ ability to judge the position and distance of a target. Abnormal responses included under- or overshoot of the intended position and lack of coordination of movement. | The subjects were asked to touch their nose alternatively with their right and left index fingers several times. Abnormal responses included under- or overshoot of the intended position and lack of coordination of movement. |
| Chair stand test | Subjects sat in a chair and placed their hands, crossed at the wrists, on the opposite shoulder. They kept their feet flat on the floor and their back straight. They were then asked to rise to a full standing position while keeping their arms against their chest. Subjects failed this test when they could not stand up without assistance or when they used their arms to complete the test. | Subjects sat in a chair with their arms at their sides. They kept their feet flat on the floor and their back straight. They were then asked to rise to a full standing position without using their arms. Subjects failed this test when they could not stand up without assistance or when they used their arms to complete the test. |
| Postural stability | Subjects stood with their 2 feet together, their arms crossed in front of their body, and they tried to maintain their balance with their eyes open and subsequently with their eyes closed. Losing balance was defined as large body sway, placing 1 foot in the direction of the fall, or falling. | Subjects stood up from the prone position and tried to maintain their balance with their eyes open. They placed their feet at a comfortable position, about shoulder width apart, arms at their sides. Losing balance was defined as large body sway, placing 1 foot in the direction of the fall, or falling. |
| Tandem walking | Subjects were walking in a straight line with the front foot placed such that their heel touched the toe of the standing foot. Abnormal gait was characterized by jerky, unsteady motion of the trunk and an unsteady gait, as well as spreading the legs apart to widen the base of support. | Subjects were walking with the front foot placed such that their heel touched the toe of the standing foot. Their arms were crossed in front of the body. A successful test was characterized by completing steps in a heel-to-toe fashion without gaps, side-stepping, or pausing for several seconds to regain balance. |
Abbreviation: ISS, International Space Station.