ISO/TR 9241-393:2020

TECHNICAL ISO/TR
REPORT 9241-393
First edition
2020-03
Ergonomics of human-system
interaction —
Part 393:
Structured literature review of
visually induced motion sickness
during watching electronic images
Reference number
ISO/TR 9241-393:2020(E)
©
ISO 2020

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ISO/TR 9241-393:2020(E)

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ISO/TR 9241-393:2020(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Theories of visually induced motion sickness . 2
5 Measurement of visually induced motion sickness . 3
6 Effective factors of visually induced motion sickness. 8
6.1 General . 8
6.2 Effective factors: Visual image factors . 8
6.2.1 General. 8
6.2.2 Role of visual motion . 9
6.2.3 Real and virtual motion .10
6.2.4 Constant rotation of global image motion .11
6.2.5 Change of velocity of global image motion .14
6.2.6 Cyclic rotation of global image motion .16
6.2.7 Cyclic translation of global image motion .17
6.2.8 Velocity effects of forward motion with complicated motion .18
6.2.9 Off-axis rotation of visual yaw rotation . .20
6.2.10 Combination of different axes of visual motion .22
6.2.11 Anisotropy effects of back and forth translation .25
6.2.12 Spatial frequency of visual image .26
6.2.13 Spatial pattern of visual image .27
6.2.14 Independent visual background from visual motion .28
6.2.15 Chromaticity of visual image .29
6.2.16 Blur of visual image .30
6.2.17 Cognitive orientation cues of visual image .31
6.2.18 Stereoscopic image .32
6.2.19 Prediction signs for motion .38
6.3 Effective factors: Visual environmental factors .41
6.3.1 General.41
6.3.2 Image size in visual field .42
6.3.3 Perspective difference between capturing and rendering images .45
6.3.4 Time delay in HMD .46
6.3.5 Duration and repeated exposure to visual stimulus .48
6.3.6 Changes in illumination colour .49
6.3.7 Auditory stimulation .51
6.3.8 Odour simulation .52
6.4 Effective factors: Individual viewer factors .53
6.4.1 General.53
6.4.2 Gender .54
6.4.3 Gender – Menstrual cycle - .57
6.4.4 Age . .58
6.4.5 Active/Passive viewing . .59
6.4.6 Fixation .60
7 Susceptibility probability of motion sickness.62
8 Scaling of VIMS severity .63
9 Summary .65
Annex A (informative) Overview of the ISO 9241 series .66
Annex B (informative) Scaling symptoms severity induced by visual motion .67
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Annex C (informative) Effective factors from the viewpoint of image production .69
Bibliography .78
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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 4,
Ergonomics of human-system interaction.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
A list of all parts in the ISO 9241 series can be found on the ISO website.
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Introduction
Recent advancements in moving image technology have enabled us to view and interact with images
using various display devices and in various ways. Moreover, application fields are not limited to
entertainment but also to other business scenarios with the expectation to expand to more ambitious
applications.
In terms of the expansion of application fields and utility forms, the role of video images serving society
has become increasingly important. Thus, it has become necessary to consider the ergonomic aspects of
utilizing video images in view of further progressive expansions. In relation to ergonomic aspects, we
need to consider not only the specifications of devices but also those affecting image safety, including
those for reducing visually induced motion sickness, or VIMS. VIMS, which is similar to motion sickness,
is usually recognized as simply being a minor annoyance from which those being affected would recover
in the short term. However, some people experiencing this sickness suffer from vomiting or ataxia, and
thus, are incapacitated.
Yet, the ambitious production of moving images and the use of those images should not be hindered
by considerations to reduce VIMS. Major factors causing VIMS are considered to be visual motion of
various kinds in moving image. In addition, visual motion in moving images conveys various types of
information, for example, the psychology of characters captured by camera work producing various
types of visual motion. For moving images shown to the public and those produced by professional
staff, VIMS is presumed to be carefully considered based on empirical knowledge. Besides, adventurous
trials can sometimes be necessary to drive forward ambitious moving image production and the use of
those images. Moreover, in the absence of empirical knowledge, the uncharted territory of visual effects
can come into existence through technical innovations. Although image safety is naturally important,
these progressive approaches should not be fully restrained. The issue can be addressed by advancing
moving image technology based on an understanding of the characteristics of VIMS. Thus, it is highly
important to accumulate scientific knowledge on VIMS. This will encourage attempts to ambitiously
produce moving images while considering image safety, which can be expected to lead to further
development in the effective use of moving images.
With a view to international standardization for reducing the incidence of VIMS, this document attempts
to summarize the scientific knowledge of VIMS by presenting an effective procedure for developing
an advanced understanding of VIMS. This is achieved from the viewpoint of empirical knowledge on
VIMS obtained during the production of moving images. This document categorizes related scientific
knowledge on the ergonomic characteristics of VIMS, and clarifies the conditions under which VIMS can
be induced and ways to reduce it. These actions are expected to develop the basis for ambitious moving
image production and the use of these images. Furthermore, the work is expected to provide effective
and basic data to allow VIMS to be studied together with a discussion of the guidelines focusing on VIMS.
While this document basically focuses on scientific knowledge of VIMS, postural ataxia or disorientation
as an aftereffect of visual exposures especially to virtual environment, is another related issue and is
even more important from the viewpoint of safety in daily life. However, this document cannot directly
deal with the issue because of shortages of scientific reports on it. This should be further examined,
and scientific knowledge of the characteristics should be accumulated.
This document does not include any guidelines. Moreover, this document is based on up-to-date data of
the ergonomic characteristics of VIMS and can be revised as new scientific data become available.
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TECHNICAL REPORT ISO/TR 9241-393:2020(E)
Ergonomics of human-system interaction —
Part 393:
Structured literature review of visually induced motion
sickness during watching electronic images
1 Scope
This document gives the scientific summaries of visually induced motion sickness resulting from
images presented visually on or by electronic display devices. Electronic displays include flat panel
displays, electronic projections on a flat screen, and head-mounted displays.
Different aspects of human-system interaction are covered in other parts of the ISO 9241 series (see
Annex A).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
visually induced motion sickness
VIMS
motion sickness-like symptoms induced by perceived motion within the visual environment, such as
when watching movies and screen images of video games
Note 1 to entry: The symptoms may include dizziness (3.2), vertigo (3.3), sweating, odd feelings in the stomach,
and nausea which can progress to vomiting.
3.2
dizziness
physical unsteadiness, lack of balance or light-headedness
3.3
vertigo
sensation of rotation or movement of oneself (subjective vertigo), or of rotation or movement of one’s
surroundings (objective vertigo), in any plane, caused by diseases of the inner ear, or by disturbances of
the vestibular centres or pathways in the central nervous system
3.4
postural ataxia
inability to coordinate voluntary movements for maintaining posture, caused by dysfunction to sensory
nerve inputs, motor nerve outputs, or the processing of them
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3.5
disorientation
loss of sense of direction, position or relationship with the surroundings
3.6
global image motion
wide spatial range of visual motion composed of different velocities and directions that are
systematically aligned in a moving image
Note 1 to entry: There are generally six types of global image motion that correspond to the different types of
motion of a camera during the shooting of images. These are rotation around and translation along the pitch,
yaw, and roll axes (see Figure 1).
Key
1 yaw
2 pitch
3 roll
Figure 1 — Rotations around and translation along the three axes
3.7
vection
self-motion perception induced by visual motion
Note 1 to entry: Vection can be categorized into two different types: linear vection and circular vection. Liner
vection consists of linear self-motion perception, while circular vection consists of circular self-motion perception
around either one or several of the yaw, pitch, and roll axes.
3.8
design field of view
design FOV
angular region subtending the active area of a display as designed to be observed from the viewing
position
4 Theories of visually induced motion sickness
Although the specific mechanism of VIMS has not been clarified, there are several hypotheses to explain
the cause of motion sickness (MS) including VIMS. Major hypotheses of MS are:
1) sensory conflict theory, or sensory rearrangement theory;
2) poison theory; and
3) postural instability theory.
The sensory conflict theory (Reason and Brand, 1975) explains the cause of MS as the mismatch among
different types of sensory information, and even within single modalities of this information, such as
visual, vestibular, proprioceptive, etc.
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The sensory rearrangement theory suggests that sickness occurs when the pattern of sensory
information containing signals from multi-modal senses and those within a single modal sense do not
match the patterns of those stored in the central nervous system, or CNS, from past experiences. As a
modified version of this sensory rearrangement theory, the theory that focuses on sensory mismatch
of the subjective vertical is known as subjective vertical theory. The sensory rearrangement theory
holds that the severity of sickness increases when the discrepancy between the pattern of sensory
information signals and those stored in CNS becomes larger. When we consider and clarify the meaning
of “mismatch” among different senses, it leads to the sensory rearrangement theory, which is widely
accepted among researchers. In general, the sensory rearrangement theory is often referred to as
sensory conflict theory.
The poison theory (Treisman, 1977) is used to explain why MS arises. The idea is that MS was developed
collaterally for organisms to survive in the course of evolution. According to the theory, when emesis
was established as a reaction to intoxication by poison, organisms developed a process in which
dizziness and vertigo, and then postural instability, is induced while the gastrointestinal tract is being
emptied by producing mismatch signals among the visual, vestibular, and proprioceptive modalities.
Because of this process, emesis is induced without the ingestion of poison by actual mismatch between
the different types of sensory information. This theory is interesting but difficult to examine and it
generally does not contradict other theories trying to explain the mechanism of VIMS.
The postural instability theory (Riccio and Stoffregen, 1991) explains the cause of MS as the state of
postural instability. Organisms try to keep postural stability in accordance with their environment in
daily activities. The stable state can be obtained by reduce body fluctuations to the smallest, while
remaining fluctuations cannot be fully controlled. According to the theory, sickness occurs when a
stable state cannot be obtained. Moreover, the severity of sickness can be determined by the time the
body remains in the unstable state. There are various discussions, both from positive and negative
sides, on this theory.
5 Measurement of visually induced motion sickness
Measurement methods of VIMS can be mainly categorized as subjective measures of symptoms or
physiological recordings including those of autonomic nervous activities. Subjective measures can be
basically classified into two categories:
1) evaluation of sickness severity with one axis scale; and
2) evaluations of various symptoms related to the sickness, which are then used to obtain a total score
and several sub-scores.
The measurements required to evaluate one value of sickness severity can be obtained in a short time.
Then, those measurements can be carried out while participants are exposed to stimuli of VIMS during
experiments. These kinds of measurements were proposed by various researchers who used different
scales. Thus, it is rather difficult to directly compare the data obtained in different experiments by
different researchers. The scales can be different in light of:
a) the number of points of the scale,
b) the level of severity indicated by the largest score, and
c) the kind of symptom levels attributed to each score of the scale.
The number of points on the scale is inconsistent: some of them have 20, and others have 11, 7, 6,
and 4. Keshavarz and Hecht (2011a) proposed a fast motion sickness scale (FMS), which is a 20-point
rating scale ranging from zero (no sickness at all) to 20 (frank sickness). They examined and found
high correlations with the simulator sickness questionnaire (SSQ), total score (r = 0,79) and sub-score
(r = 0,83). They also used it in another experiment (Keshavarz and Hecht, 2011b).
There are two different, but comparable, scales adopting 11-point levels of scoring. One is called the
misery scale (MISC), which has been used by Bos and his colleagues (Bos et al., 2005; Lubeck et al.,
2015; Lubeck et al., 2016). The scale was revised from the one adopted by Wertheim et al. (1998), based
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on “the knowledge that nausea is generally preceded by other symptoms such as dizziness, headache,
(cold) sweat, and stomach awareness” (Bos et al., 2005). The MISC with symptom description for each
score is shown in Table 1. The other is the sickness related scale, focusing on the symptoms felt in the
head, and of dizziness and nausea (Ujike et al., 2004; Ujike et al., 2005). The scale is presented in Table 2.
Table 1 — Misery scale (MISC)
Symptom Severity Score
No problems 0
Uneasiness (no typical symptoms) 1
Dizziness, warmth, headache, stomach awareness, sweating, and vague 2
other symptoms slight 3
fairly 4
severe 5
Nausea slight 6
fairly 7
severe 8
Retching 9
Vomiting 10
Table 2 — Sickness related scale
Symptom description Rating
No problems 0
Feeling very slight unusual sensation 1
Feeling slight unusual sensation 2
Tendency to feel unusual sense in the head 3
Sometimes feeling unusual sense in the head 4
Feeling unusual sense in the head 5
Tendency to feel sick and dizziness 6
Feeling slight sick and dizziness 7
Feeling sick and dizziness 8
Feeling very sick and dizziness 9
Cannot see visual motion, or feel vomiting 10
A 7-point scale is used in several reports (Webb and Griffin, 2002; Webb and Griffin, 2003; Lo and So,
2001; So et al., 2001; Ji et al., 2009), and attributes symptom levels to each score as:
— 0 = no symptoms;
— 1 = any unpleasant symptom, however slight;
— 2 = mild unpleasant symptom;
— 3 = mild nausea;
— 4 = mild to moderate nausea;
— 5 = moderate nausea, but can continue;
— 6 = moderate nausea, want to stop.
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A 6-point scale is used by other researchers (Bijveld et al., 2008; Golding et al., 2009), of which the scale
indicates the symptoms as:
— 1 = no symptoms;
— 2 = initial symptoms, but no nausea;
— 3 = mild nausea,
— 4 = moderate nausea (stop motion);
— 5 = severe nausea;
— 6 = vomiting.
A 4-point scale was produced by Bagshaw and Stott (1985) and is used by some studies (Clemes and
Howarth, 2005; Diels and Howarth, 2011; Diels and Howarth, 2013), of which the range is:
— 1 = no symptoms;
— 2 = mild symptoms, but no nausea;
— 3 = mild nausea;
— 4 = moderate nausea.
Another 4-point scale, which simply indicates “general discomfort”, one of the 16 items adopted in SSQ,
was used by others (Ujike et al., 2005b).
To date, several different methods have been proposed for scoring, with the evaluation of multiple
symptoms. One of these methods uses the Graybiel scale of MS (Graybiel et al., 1968). Alternative forms
of the method have been derived. The Graybiel scale has 7 categories of symptoms for evaluating MS
(see Table 3). For each of the categories, the severity of symptoms is evaluated, and then a total score is
obtained (Hu et al, 1989; Andre et al., 1996). Depending on the total score, the level of severity of MS can
be categorized as being one of five different levels.
Table 3 — Categories and levels of severity of the Graybiel scale
a
Pathognomonic Major Minor Minimal AQS
Category
16 points 8 points 4 points 2points 1 point
Vomiting or Epigastric Epigastric
c b d
Nausea syndrome Nausea II , III Nausea I
retching discomfort awareness
b c d
Skin colour Pallor III Pallor II Pallor I Flushing
b c d
Cold sweating III II I
Increased
b c d
III II I
salivation
b c d
Drowsiness III II I
Pain Headache
Dizziness:
Central nervous
c
Eyes closed ≥II
system
b
Eyes open III
Levels of severity identified by total points scored
a
Additional qualifying symptoms.
b
Severe or marked.
c
Moderate.
d
Slight.
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Table 3 (continued)
a
Pathognomonic Major Minor Minimal AQS
Category
16 points 8 points 4 points 2points 1 point
Frank Severe Moderate Moderate
Slight malaise
sickness malaise malaise A malaise B
(S) (M III) (M IIA) (M IIB) (M I)
≥16 points 8–15 points 5–7 points 3–4 points 1–2 points
a
Additional qualifying symptoms.
b
Severe or marked.
c
Moderate.
d
Slight.
Some related scoring methods exist. These methods score eight different symptoms with four levels
of severity: 0 = none, 1 = mild, 2 = moderate, 3 = severe. Some researchers adopted these eight
different symptoms as: vertigo, dizziness, bodily warmth, headache, increased salivation, stomach
awareness, nausea, and dry mouth (Bonato et al., 2005; Bonato et al., 2004; Bubka and Bonato, 2003).
Others adopted the eight symptoms as being: dizziness, bodily warmth, headache, sweating, stomach
awareness, increased salivation, nausea, and pallor that are rated by an experimenter (Golding et al.,
2009; Bijveld et al., 2008).
Another scoring system, that is widely used, is the simulator sickness questionnaire (SSQ) developed
by Kennedy et al. (1993). The SSQ has 16 items of symptoms to be eval
...