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Motion Sickness Theories
14 November 2006 Lauralee Flores Psych 562,
Advanced Human Factors
2
Overview

• Bles, W., Bos, J. E., Graff, B. d., Groen, E.,
  wertheim, A. H., (1998). Motion sickness Only
  one provocative conflict? Brain Research Bulletin
  47 (5), 481-487.
• Sensory rearrangement theory re-defined by
  demonstrating that only one type of conflict is
  necessary and sufficient to explain all different
  kinds of motion sickness (rather than 2).
• Turner, M. Griffin, M. J., (1999). Motion
  sickness in public road transport passenger
  behavior and susceptibility. Ergonomics 42 (3),
  444-461.
• Identified personal and environmental factors
  influencing individual susceptibility to motion
  sickness during road transport.

3
Bles et al. (1998) Introduction

• Classic Sensory Rearrangement theory
• Situations that provoke motion sickness are
  characterized by a condition of sensory
  rearrangement in which the motion signals
  transmitted by the eyes, the vestibular system
  and the nonvestibular proprioceptors are at
  variance either with one another or with what is
  expected from previous experience.
• The two types of conflict (with the
  visual-vestibular mismatch)
• Type 1 conflict when both systems signal
  simultaneously contradictory motion information
• Type 2 conflict when one system signals motion
  in the absence of a corresponding signal from the
  other sensor.

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Bles et al. (1998) Introduction

• Omans (1982) contribution 33
• Mathematical model for the classic sensory
  rearrangement theory on motion sickness.
• Motion sickness is related to the vector
  difference between a vector representing all the
  available afferent sensory information and a
  vector representing the expected sensory
  information.
• When this difference vector grows, the chance of
  motion sickness and the severity of the motion
  sickness will increase.
• Oman pinpoints the conflict to a discrepancy
  between the sensed and expected information of
  all individual sensors.

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Bles et al. (1998) Introduction

• Bles et al. purport that motion sickness is
  primarily provoked in those situation where the
  determination of the subjective vertical, the
  internal representation of gravity, is
  challenged.
• Example long duration centrifugation
• Only head movements that change the orientation
  of the head relative to the gravity vector
  provoke motion sickness.
• Sensory mismatches may induce motion illusions
  but only provoke motion sickness when the
  determination of the subjective vertical is at
  stake.

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Bles et al. (1998) Introduction

• Sensory rearrangement theory on motion sickness
  redefined
• All situation which provoke motion sickness are
  characterized by a condition in which the sensed
  vertical as determined on the basis of integrated
  information from the eyes, the vestibular system
  and the non-vestibular proprioceptors is at
  variance with the subjective vertical as
  predicted on the basis of previous experience.

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Bles et al. (1998) Introduction
Leading to a position x due to the body dynamics
External Noise
Desired position
Muscle activity is generated
The two signals is detected by the senses
Resulting in sensory information
The origin of motion sickness
Oman also assumes that an internal model that
consists of the same components (indicated with a
hat) computes the expected sensory information
The c vector is the difference between a and a
hat.
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Bles et al. (1998) Introduction
Bles et al extend Omans model in these ways
Keep in mind that because d is a vector not only
its magnitude but also its direction may affect
the severity of motion sickness.
Sensed vertical based on the incoming sensory
information
The origin of motion sickness
Expected vertical based on previous experience
and expectation
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SV-Conflict Theory vs. General Sensory
Rearrangement Theory

• General Sensory Rearrangement Motion sickness
  characteristics are different among the various
  forms of motion sickness
• SV-Conflict Theory Despite these differences all
  types of motion sickness have one underlying
  conflict in common, which is the conflict about
  the subjective vertical.
• Motion sickness explained
• GSR The consequence of passive motion because
  then the expected signals (a hat) will be
  different from the sensed (a) ones increasing the
  c vector.
• SV-C Passive motion does not necessarily
  influence the magnitude and the direction of the
  subjective vertical so d is not always
  increasing.

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SV-Conflict Theory vs. General Sensory
Rearrangement Theory

• What happens to the vectors c and d when a
  subject is given a sudden push?
• SV-Conflict Theory
• Before push Sensed vertical subjective
  vertical
• After push d has minimal change, suggesting that
  the subject should not get motion sick.
• General Sensory Rearrangement Theory
• Before push a a hat
• After push c increases dramatically thus
  provoking motion sickness according to the
  general sensory conflict theory.
• Conclusion
• The subject should not get motion sick (only
  angry about the push)

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Coriolis Effect

• Coriolis Effect nausea provoked by making head
  movements during yaw motion.

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Coriolis Effect

• Coriolis Effect
• Tilt of the head on the shoulder in darkness
  during constant velocity rotation is very
  provocative.
• The greater the tilt the more provocative it is.
  The less the movement of the head the less
  provocative it is.
• Conclusion
• This is in perfect agreement with the SV-conflict
  theory

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Sea Sickness

• The vertical motion was the only motion
  component that contributed to the motion sickness
  incidence and described this incidence
  mathematically as a function of amplitude,
  frequency and exposure time for pure vertical
  sinusoidal motion (p.484).
• Vertical motion of the ship corresponded best
  with the motion sickness incidence (p. 484).
• The frequency range around 0.2 Hz is the most
  provocative (p.484).
• The fact that head movements play an important
  role in the enhancement of sea sickness can also
  be derived from the advise to minimize head
  movements as much as possible to prevent sea
  sickness (p.484).

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Air, Car Simulator Sickness

• Air Sickness Passengers in civil transport
  aircraft, bumpy weather is known to provoke air
  sickness
• Car Sickness Driving uphill at night along a
  winding road may provoke car sickness in the
  passengers in the back seat.
• Simulator Sickness occurs if an individual is
  motion sick in the simulator but the original
  motion did not provoke motion sickness.
• It is a common observation that experienced
  fighter pilots suffer more from simulator
  sickness than student pilots. This may due to
  the fact that the experienced pilots have a fully
  developed expectation about the incoming sensory
  signals, which are not matched on the sensory
  side.

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Discussion

• The SV-conflict Theory has only one conflict of
  interest that between the subjective (or
  expected) vertical and the sensed vertical.
• It is an interesting question why the subjective
  vertical is so important that problems in
  determining the subjective vertical cause motion
  sickness.

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Discussion

• Some arguments
• The vertical is critical for the organism to
  maintain the upright postural position.
• This is supported by the view of some workers in
  this field who have built an entire motion
  sickness theory around the control of body
  orientation.
• The authors feel that all motion
  sickness-provoking conflicts can be pinned down
  to only one conflict is justified in view of the
  analysis of the different types of motion
  sickness

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Turner, M. Griffin, M. J., (1999). Motion
sickness in public road transport Passenger
behavior and susceptibility. Ergonomics, 42 (3),
444-461.
18
Turner Griffin

• The aim of this research was to identify personal
  and environmental factors influencing individual
  susceptibility to motion sickness during road
  transport.

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Turner Griffin-Introduction

• What causes motion sickness?
• Specific motion exposure
• Large variability in sickness response
• Gender
• Age
• Previous motion sickness
• Regularity of travel
• Why do drivers rarely become motion sick?
• Their greater ability to control and predict
  motion stimuli
• The attentional demands of driving leave little
  room for dwelling on or envisioning motion
  sickness

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Turner Griffin-Introduction

• How to reduce motion sickness
• Performing mental tasks
• Adopting supine body postures
• Reducing head movements by holding the head
  against the back of the seat
• Feelings of warmth are often an early symptom
• Ambient air temperature is reported to have no
  influence on sickness susceptibility
• Activities thought to increase motion sickness
• When passengers are deprived of a good external
  view (i.e., reading)
• Using visual displays and performing visual
  search tasks
• Odors from vehicle fumes (assumed)
• Food consumed during travel (assumed)
• Time of day
• Time interval since last eating a meal
• Recent research has suggested that high-fat
  content meals and stage of food digestion when
  motion is experienced can influence nausea
  occurrence.

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Turner Griffin-Introduction

• Research in laboratory and at sea has been done.
• The current study sought to determine the
  importance of passenger characteristics and
  non-motion environmental factors as determinants
  of motion sickness during road travel.
• Hypothesis prior susceptibility to motion
  sickness may predispose passengers to different
  travel behaviors which in turn may account for
  variations in sickness occurrence.

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The validity of this scale has been examined in
a previous survey of motion sickness (Lawther and
Griffin 1986)
Two measures of motion sickness Symptoms
Illness rating
No significant differences were observed between
coach type or route types with respect to mean
passenger age, of male to female passengers,
self-rated motion sickness susceptibility, of
passengers using anti-motion sickness measures or
travel regularity.
56 private-hire coach trips, using nine different
vehicles traveling on different routes. 3,256
participants 5 min before the end of the journey
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Results

• Why do females report more motion sickness than
  males?
• Males dont want to appear weak?
• Females are more adversely affected by the
  poor/misleading visual information?
• Age /or travel experience (habituation)
• 40 yrs /or six coach journeys in the last year

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33.8 of females and 24.0 of males reported
having no view of the road ahead.
AGE GROUP
TRAVEL EXPERIENCE
TRAVEL ACTIVITY
FORWARD VISIBILITY
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Results

• Age range 8-80 years
• Mean age 28.3 years
• Females 33.5 years
• 22.3 were over 60
• Males 22.8 years
• 7.3 were aged over 60
• Females were significantly older than males

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3 females to 1 male vomited
4 females to 3 males reported feeling sick
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Results

• Older passengers generally preferred looking from
  the window and resting or seeping.
• Younger passengers were more likely to listen to
  music, watch videos or play games.
• Passive activity (resting/sleeping, listening to
  music, doing nothing) resulted in worse motion
  sickness than looking out the window.

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Results

• The most common symptom experienced during travel
  was feeling hot or sweating, followed by
  headaches and drowsiness.

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Results

• Illness Ratings
• 22.1 slightly unwell
• 4.1 quite ill
• 2.2 absolutely dreadful
• Mean illness rating .37
• .42 for sea travelers, suggesting sea travel is
  more nauseogenic
• Incidence of vomiting on coaches 1.7
• Sea travel 7.0

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Results

• Those more susceptible became ill more often
  within the 1st hour of travel than those becoming
  ill later on.
• Significant difference in passenger age as a
  function of illness onset time.
• Younger passengers felt ill earlier than older
  passengers during a journey.
• The severity of illness was not dependent on when
  passengers first felt ill.

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Results

• Illness ratings were greater for passengers in
  backwards facing seats than in forward facing
  seats, although no significant differences in
  symptom scores or vomiting were found as a
  function of seat direction.

32
Results

• For double-deck vehicles, no significant
  differences were found between passengers
  traveling in the upper and lower saloons for any
  of the sickness measures used.
• Temperature measures little influence on motion
  sickness occurrence.

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Results

• Sickness occurrence was approximately 3X more
  likely in passengers with no forward view
  compared with those who had extremely good
  forward visibility.
• Inappropriate visual stimuli may double the
  incidence of motion sickness (Money, 1970).

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Results

• 7.2 of coach passengers used anti-motion
  sickness drugs, compared with 26.0 of sea
  travelers.
• Susceptibility ratings were higher for passengers
  using anti-motion sickness measures.
• No significant difference between different types
  of anti-motion sickness measures.
• Passengers feeling sick
• 52.3 used motion sickness measures
• 26.6 didnt use motion sickness measures
• Passengers vomiting
• 5.6 used motion sickness measures
• 1.4 didnt use motion sickness measures

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Results
37.3
23.1

• Over ½ of the surveyed population (58.2)
  reported suffering from motion sickness
  previously in one or more forms of transport.
• The average coach passenger had previously
  suffered from travel sickness in at least one
  form of transport (with females more than males)
• Passengers who had previously experienced some
  form of motion sickness showed large increases in
  illness ratings when sitting at the rear of the
  coach or in seats that provided poorer forward
  visibility.

1 3 2 4 5
29.2
10.0
3.8
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Results

• Less frequent travelers experiencing greater
  sickness
• Is this a result of age or travel experience?

Sickness reduced with age independently of travel
experience.
37
Results

• Experienced travelers were more likely to
• Sit in window seats than aisle seats
• Sit towards the front of each vehicle
• Sit in seats that afforded better forward
  visibility

38
Results

• Eating before travel versus during resulted in
  less motion sickness symptoms and less vomiting.
  
• There was no significant difference between those
  eating large meals versus snacks. However, it
  was observed that eating large amounts resulted
  in more motion sickness and vomiting than eating
  snacks or sweets.

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Results

• Illness ratings, symptom scores, and vomiting
  occurrence differed significantly with seat
  location along the longitudinal axis of each
  vehicle, with sickness increasing from front to
  rear.
• Sickness occurrence was greatest at the rear of
  coaches where external vision was reduced and
  magnitudes of nauseogenic motion are known to be
  greatest.
• Illness ratings, symptom scores, and vomiting
  occurrence were significantly greater for
  passengers in aisle seats than for passengers in
  window seats.

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Summary

• Approximately one in every four passengers felt
  unwell during coach travel.
• One in every eight coach passengers experienced
  nausea.
• Over one-half reported other symptoms sometimes
  associated with motion sickness.
• Time of day had little influence on motion
  sickness occurrence.
• 23 of coach passengers had previously suffered
  from sickness during coach travel. This is
  representative of the general population.
• This suggests that people dont avoid coach
  travel due to fear of sickness

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Conclusions

• Passengers with a low susceptibility to motion
  sickness were more likely to engage in supposedly
  more provocative activities.
• Susceptible passengers were more likely to remain
  passive during coach travel.
• The expectancy of travel sickness may therefore
  have determined travel activity rather than
  travel activity determining the occurrence of
  sickness.
• Similar result with anti-motion drugs

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Conclusion

• What factors play a role in motion sickness in
  public road transport?
• Passenger Age
• Gender
• Regularity of travel
• A good forward view
• What this study offered in addition to the above
  
• Habituation (through greater travel regularity)
  occurs independently of reductions that occur
  with age
• Females are more affected by poor forward
  visibility