**2.6 Simulator Sickness:**

Definition of simulator sickness

Predisposing and contributing factors

Symptoms and signs

Performance effects

Prevention and treatment

An increasingly common variation of airsickness is simulator sickness.
This form of motion sickness occurs in certain flight simulator with
integrated projections of visual fields outside the cockpit,
corresponding interior instrument readings, and a limited degree of
motion simulation. As with airsickness, and all other forms of motion
sickness, a sensory mismatch occurs. It is difficult to achieve high
fidelity between the visual input and vestibular and proprioceptive
stimulation. Some flight simulators have no motion simulation at all,
and therefore all the motion inputs are visual, without the normal
accompanying proprioceptive and vestibular stimuli. This typically
results in much higher rates of so called simulator sickness in
experienced pilots, who are used to the environment where all motion
stimuli are coordinated. Even full-motion simulators, called 6 degree of
freedom simulators, which produce roll, pitch, yaw, as well as X, Y and
Z linear acceleration, cannot fully reproduce the vestibular and
proprioceptive sensations.

![](media/image1.jpeg){width="5.75in" height="3.75in"}

Simulator sickness and its variation, vection illusion, occur in
everyday life. For example, an individual who has been driving an
automobile that is stopped at a stoplight, and is presumably stationary,
may have a vehicle on either side of it creep forward, giving the driver
a sensation that they are moving backwards because of the peripheral
vision input, even in the absence of proprioceptive and vestibular input
of acceleration. Another variation is called the Star Wars effect
because of the visual effects creating the sensation of motion. This has
been exploited in various forms of commercial rides and motion
simulators, which are sometimes coupled with a limited degree of actual
motion simulation of the seated occupants. The effects are the same, as
with any motion sickness: malaise, fatigue, increasing stomach
awareness, nausea, cold sweats, vomiting and even prostration.

Individuals with specific experience in a moving situation are
predisposed to simulator sickness. As noted before, instructor pilots
tend to have much more problems with a flight simulator than their
students -- quite the reverse of the actual cockpit experience. The
effects on performance are significant and can degrade the individual's
performance for many hours afterwards. In some major airlines, the early
experience with high-fidelity 6 degree of freedom simulators was such
that an individual was often prohibited from flying an actual aircraft
for 24 hours following a training exercise in a simulator. The
simulators are excellent for procedures and emergency training, but are
not completely true to the real world when it comes to simulating the
actual motions, although they are superior to a non-moving simulator. As
with airsickness, the best treatment is conditioning and prolonged
exposure. Most individuals with simulator sickness problems will rapidly
adapt to the environment if enough time and training are permitted.
Rarely are medications or any other intervention required.

\*Some will prefer Jason's *Argo* as the first ocean-going vessel in
recorded history. He did not transport elephants!

Reference: A. J. Parmet & K. Gillingham, Chapter 8: Spatial Orientation
in Flight. *In* **Fundamentals of Aerospace Medicine, 3rd Edition,**
Edited by R. L. DeHart and J. Davis, Lea & Febiger, Philadelphia, 2002.

Illustrations courtesy of Dr. Parmet, ©2002.