Prediction of Space Motion Sickness

 

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))