The probability of space motion sickness in a subject can be predicted based on the results of provocative tests.
Variables
age: age in years
sex: 0 if male, 1 if female (values not stated in article, but inferred as values need to give a mean of 0.229 in Table 15 page 297 with number of men and women present)
Coriolis Sickness Susceptibility Index (CSSI, described page 271):
(1) CSSIP: symptom score (mean value Table 15 is 7.5)
(2) CSSIR: investigator rating on CSSI test as described on page 283 (severely susceptible, moderately susceptible,low-to-nonsusceptible); assume scores 1, 2, 3 to give mean of 2.277 in Table 15
Off-Vertical Rotation (OVR, described page 272):
(1) OVR: test score, with test terminated when the subject reaches MIII level of malaise or the chair had been maintained at 30° for 5 minutes; mean score 28.422 in Table 15
(2) OVRP: symptom score; mean score 6.036 in Table 15
(3) OVRR: investigator rating on test as described on page 283 (severely susceptible, moderately susceptible, low-to-nonsusceptible); assume scores 1, 2, 3 to give a mean of 1.024
Sudden Stop Test (described page 272):
(1) SSTEO (Sudden-Stop Eyes Open): test score with maximum of 40 trials (20 trials in one direction, then 20 trials in opposite direction); mean value in Table 15 were 10.6
(2) SSTEC (Sudden-Stop Eyes Closed): test score (20 trials in one direction, then 20 trials in opposite direction); mean value in Table 15 was 21.735
Postural Equilibrium Test (described page 273-274):
(1) EORAIL: test score during eyes-open postural ataxia test on the 4.45 cm rail width; apparently the score is the cumulative time able to be balanced over 3 trials with a maximum of 50 seconds each (page 274); mean value in Table 15 is 88.855
(2) ECRAIL: test score during eyes-closed postural ataxia test on the 5.72 cm rail width; mean value in Table 15 is 40.325
Prediction of Vomiting in Response to KC-135 Parabolic Flight
X =
= 50.00 - (0.993297 * OVR) + (2.946896 * OVRP) - (7.032591 * OVRR) - (0.013862 * SSTEC) - (0.131049 * EORAIL) - (0.846387 * AGE)
probability of vomiting =
= EXP (X) / (1 + EXP(X))
probability not vomiting =
= 1 - (probability of vomiting)
Prediction of Sickness in Response to KC-135 Parabolic Flight
Y =
= (-0.466127) - (0.842366 * SEX) - (0.204598 * CSSIP) + (0.077794 * SSTEO) + (0.016353 * EORAIL)
probability of not getting sick =
= EXP (Y) / (1 + EXP(Y))
probability of getting sick =
= 1 - (probability of not getting sick)
Prediction of Degree of Susceptibility
U =
= 0.544164 - (0.192917 * CCSIP) + (0.317659 * CSSIR) + (0.054141 * SSTEC) - (0.002492 * EORAIL) + (0.001270 * ECRAIL)
V =
= 3.216510 + (0.10865 * CCSIP) - (0.744345 * CSSIR) + (0.0153 * SSTEC) - (0.028385 * EORAIL) - (0.027213 * ECRAIL)
probability of low susceptibility =
= EXP(U) / (1 + EXP(U) + EXP(V))
probability of moderate susceptibility =
= EXP(V) / (1 + EXP(U) + EXP(V))
probability of high susceptibility =
= 1 / (1 + EXP(U) + EXP(V))
Specialty: Emergency Medicine, Critical Care