Background: Virtual environment (VE) technology has many promising applicat
ions in a variety of areas that may likely lead to widespread use as techno
logy progresses and cost decreases. Recent research has demonstrated that s
imulator sickness, a well-established effect of simulator exposure, can occ
ur with VE exposure as well. Because ataxia (postural unsteadiness) is know
n to occur following simulator exposure, it might also occur following VE e
xposure. Simulator sickness and after-effects, such as ataxia, pose severe
safety risks and raise serious liability questions. Method: A PC-based VE s
ystem was used to investigate the occurrence of ataxic decrements in postur
al stability following a 20-min exposure to a commercially available game.
There were 20 male and 20 female undergraduate students who served as parti
cipants. Postural stability was assessed using a sensitive, reliable measur
e of stance involving the velocity of head movement sway along the y-axis.
Data on the occurrence of simulator sickness were also collected. Based on
findings in other simulators, ataxia was hypothesized to occur. Results: At
axic decrements in postural stability were not found although simulator sic
kness did occur. Conclusions: Several possible factors possibly involved in
the lack of ataxia were considered: statistical power; aspects of the post
ural test; participants' VE-adaptation, exposure time, and immersion positi
on; and the task performed. Ataxia may not be associated with short exposur
es to VEs for asks which are not highly dynamic and individuals who are not
experienced with the system.