The Coriolis Sickness Susceptibility Index

 

Procedure:

(1) The patient is seated in a rotating chair device that spins at one of several constant velocities.

(2) While seated, the patient experiences standard head movements of 90° in the frontal and sagittal planes. Position 1 has the head bent forward, position 2 bent to the right, position 3 bent backwards, position 4 to the left and finally position 5 has the head bent forward once more.

(3) The endpoint is the number of head movements required to provoke symptoms of severe malaise (M III), although a few persons may remain symptom free despite marked stimulus.

(4) Any person who was tested at the 30 rpm speed who failed to reach the endpoint was not retested since this indicated relative immunity to motion sickness. Otherwise, if the patient did not experience MIII symptoms within the range of 40 to 166 head movements, then the test was considered invalid and the test repeated after a rest period of 48 hours.

 

The E factor is the average stress effect of each head movement for the rpm (rotations per minute) used in the test.

Chair Velocity in RPM	LOG10 (RPM)	E Factor	LOG10(E)
2.5	0.397	0.006	-2.2218
5.0	0.699	0.021	-1.67778
7.5	0.875	0.046	-1.337
10.0	1.000	0.078	-1.1079
12.5	1.097	0.118	-0.928
15.0	1.176	0.165	-0.7825
20.0	1.301	0.28	-0.5528
25.0	1.3979	0.43	-0.3665
30.0	1.477	0.60	-0.2218

(from Figure 2, page 10)

 

LOG10(E factor) =

= (1.8573207 * LOG10(RPM)) - 2.966063

 

E factor =

= 10^((1.8573207 * LOG10(RPM)) - 2.966063) =

= (10^(-2.966063)) * ((RPM) ^ (1.8573207)) =

= 0.00108128 * ((RPM) ^ 1.8573207)

 

CSSI =

= (number of head movements to elicit MIII symptoms) * (E factor)

 

Interpretation:

• Scores range from 0 to 100, with values skewed to the right.

• The higher the value, the less the susceptibility to motion sickness.