Procedure:
(1) The subject with head upright and eyes covered was accelerated clockwise at 15° per second squared and maintained at this velocity for 15 seconds. The hydraulic brakes on the centrifuge were then electrically activated and the centrifuge brought to a stop within 1.5 seconds.
(2) The subject then remained at rest for 30 seconds while various physiologic measures and any symptoms of motion sickness were recorded.
(3) The experiment was then repeated until one of the endpoints was reached.
(4) If the patient had completed the full 20 cycles, then the blindfold was removed and the subject passively looked straight ahead at a striped enclosure. The experiment was repeated until one of the endpoints was reached.
(5) If the patient finished 20 cycles with eyes open, then the direction of rotation was reversed until an endpoint was reached.
Endpoint: either
(1) reaching slight nausea, OR
(2) total series of stops as outlined above reached (20 with eyes closed, 20 with eyes open, 20 in reverse direction, for a total of 60)
Usually a series of 4 test sessions were held, with an interval in-between sessions, usually 3 days.
(1) The first session was essential for proper indoctrination but was a poor indicator of later performance.
(2) The second session was a reliable indication of susceptibility to motion sickness.
(3) The last 2 sessions provide information on acquisition and retention of adaptation effects.
score =
= (0.5 * (number of stops with eyes closed)) + (number of stops with eyes open) + (2 * (number of stops after reversing direction))
Interpretation:
• minimum score: 0.5
• maximum score: 70
• most desirable: low susceptibility to motion sickness, fast acquisition with good retention of adaptation.
• undesirable: high susceptibility to motion sickness and slow acquisition with poor retention of adaptation.
