Duration and exposure to virtual environments: Sickness curves during and across sessions

Although simulator sickness is known to increase with protracted exposure a nd to diminish with repeated sessions, limited systematic research has been performed in these areas. This study reviewed the few studies with suffici ent information available to determine the effect-that exposure duration an d repeated exposure have on motion sickness. This evaluation confirmed that longer exposures produce more symptoms and that total sickness subsides ov er repeated exposures. Additional evaluation was performed to investigate t he precise form of this relationship and to determine whether the same form was generalizable across varied simulator environments. The results indica ted that exposure duration and repeated exposures are significantly linearl y related to sickness outcomes (duration being positively related and repet ition negatively related to total sickness). This was true over diverse sys tems and large subject pools. This result verified the generalizability of- the relationships among sickness, exposure duration, and repeated exposures . Additional research is indicated to determine the optimal length of a sin gle exposure and the optimal intersession interval to facilitate adaptation .