Introduction by researchers to study perspectives, perception,

Introduction

The paper
examines how eye-tracking (ET) method make possible to early diagnosis of
autism by explaining some specific studies -especially Klin & Warren’s
study- about the topic. In contrast to some perceptions that autism takes place
at some point later on in human’s life, researcher’s assumption is that the
autism disorder has to be traced to the infancy. For infants, they can always
follow gazes of people since even before they communicate through language;
they try to decipher their environment by looking at it. Infants also learn
attitudes as well as body languages to develop meaning, but if they are
affected by autism spectrum disorder; the distinction between attraction and
attention is a challenge which impairs the process of sense making (Klin & Jones, 2006).

The inner
world of infants and individuals should be understood to have meaningful
interpretations about the spectrum. Therefore, one important research subject
is to explore activities infants engage in, the things that matter to them as
well as their perceptions of the world. Once we are able to screen and analyze
the spectrum clinically, we have the power to develop effective intervention and prevention methods which include cues
about attention, attraction, and attitude in the case of autism. Fortunately, there
are already successful technologies used by researchers to study perspectives,
perception, and experiences of autistic individuals. One important example is
the eye-tracking technology, which allows
one to see what newborns, children, and people are engaging within every moment.
This can be an effective tool to grasp attention attraction and attitude of ASD
people while providing meaning at the same time (Falck-Ytter, Bölte, & Gredeback,
2013).

This paper
carries out a critical assessment of the eye
tracking method for autism spectrum diagnosis, especially in infants.  First, the strengths and weaknesses of
tracking the eyes will be discussed. Then, the eye tracking method and autism
spectrum disorder relation will be reviewed based on their validity and reliability.
Finally, outlook will be provided for future directions.

Autism
Spectrum Disorder and diagnosis

Autism
spectrum disorder is termed as spectrum and complex because there are some
individuals with the disorder that have notable intellectual challenges while some possess special abilities. Those
people with the disorder are unique regarding strengths
and differences (Klin, Shultz, &
Jones, 2015).
Autism spectrum disorder-commonly known as Autism- is a complex condition which
is characterised by a group of
neurodevelopment disorders that causes challenges in social skills, non-verbal
communications speech, and interaction as well as having repetitive behaviours. The latter is caused by majorly by a different combination and
interaction of both genetic and environmental conditions (Durkin, Maenner,
Christensen, Daniels, & Fitzgerald, 2017). However, in regard
to environmental effect, researchers claim that the disorder is strongly associated with genetic components of
developmental disorders which usually begin
before the baby is even born (Thushara Vijayakumar,
2016).
Moreover, people with the disorder show a
deficit in nonverbal communication that is necessary for social interaction. They also
demonstrate a deficit in developing and
understanding relationships, the presence
of repetitive behaviour patterns as well
as a deficit in social and emotional
reciprocity (Semrud-Clikeman,
Jenifer, Wilkinson, & Minne, 2010). However Klin et
al., (2006) hypothesized that people with autism also have social interaction
with an environment; the difference is that they attend to physical stimulus
rather than human movement (see Appendix A) (Constantino,
Kennon-McGill, Marrus, & Klin, 2017).

 Before it was coined
as ASD, the disorder had various distinctive subtypes which included the
Childhood Disintegrative Disorder, Asperger’s Syndrome, Autistic Disorder as
well as Persuasive Developmental Disorder not otherwise specified (Association, 1994). At present autism diagnosis usually requires
that behavioural characteristics are
visible as a symptom before the age of about two or three years. In most cases,
autism spectrum’s most obvious signs start
to appear when the child is at the age of about two years. However, in some
cases, it is possible to diagnose ASD as early as six months of age. Since
autism spectrum disorder has various causes, there is a need to focus on the first two years of development (Klin, Shultz, & Jones,
2015).

Eye Tracking

Neuman et
al., (1996) states that experts may have different assessments with respect to eye
tracking as either an inadequate measure of brain function or as an improved measure
of cognition, yet it complements brain and behavioral measures at the same time.
Due to this complementation, we are able to do research on human behaviors by
objectively measuring and quantifying eye movements, eye tracking is exactly such method that allows us to study human
movement and thus, the method is useful to examine the autism spectrum
behavior patterns. One important reason for this is that the eye tracking
method includes ocular measures which provide further knowledge about
accuracy and response times. Due to its high temporal resolution, it makes possible
to measure moment by moment how people respond to certain tasks (Neumann & Sanders, 1996). Moreover, Eye
tracking is a technology that is used in measuring a person’s point of gaze-where
individual is looking-or the movement of the eye. In essence, it refers to the
recording of eye movement and its relative position in an environment (Aslin, 2012). The technique is
faster than any other input media, and therefore also useful for conducting
usability studies as well as understanding how users interact with their
environment. In relation to its speed, sampling rates of eye tracking range
indicate that the faster eye trackers achieve sub-millisecond temporal
resolution, just as happen in EEG method (Neumann & Sanders,
1996).
Although the eye-tracking measure is an indirect measure of brain function,
eye-tracking has many positive sides when we compared to EEG and fMRI. For
example, participants feel comfortable during the study because they are
provided suitable seating, and testing takes place in the natural environment
rather than the noisy environment in contrast to the fMRI scanner. Later, the
eye tracker equipment is adaptable and portable, thus, can be easily placed in a
hospital or school settings. Accordingly, eye tracker provides a large amount
of population for researchers. Lastly, contemporary eye trackers have fast calibration
procedures thus it allows us to begin an experiment quickly. This is helpful for
researchers who seek to reduce and minimize testing time (Ecksteina, Carrilloa,
Singleya, & Bunge, 2017).Finally, the
technique is enabling to track reflections from the corneal and assess the visual
attention of an individual (Luna, Katerina, &
Charles, 2008).
This is one of the main reasons why Klin and colleagues used eye-tracking as a
tool in their study on the interaction of children with autism, with their
world and environment. Their study found out that, children with autism had
attention toward sound synchronized to motion rather than social one (human
movement).

Moreover, contemporary
eye trackers dominantly utilise the
technology of visible light, which are often called infrared-free (IR-free) eye
trackers. The IR illumination is generally used in hands-free interfaces as
Kunkar and Kostek point out: ” In order to estimate the fixation (see Appendix
B) point the eye is illuminated by infrared diode light which is invisible to
the user and does not disturb his/her interaction with the computer. IR
sources, appropriately installed on the camera, to generate unique reflections
on the user’s eye” (Kunka & Kostek,
2009).
To be more precise, the camera with relatively high-resolution
has capabilities of tracking gaze positions and directions. The
technology works in a such a way that the IR light is focused on the pupil of an eye resulting to reflections in the
cornea which are eventually tracked by a high-resolution
camera. Thus, eye tracking method can reveal the visual elements that likely attract quick attention as well as those
elements that maybe be ignored and overlooked (Bryn
Farnsworth, 2016).

 

 

 

 

Eye
Movement and Autism

Autism
spectrum disorders (ASD), are the neurological conditions that are characterised by impairments arising from
deficits in social interaction, nonverbal communication as well as a deficit in imagination. ASD affects the functioning of the brain which has also been linked with a deficit in cognitive processes such as perceptions as well as
atypical attention (APA, 2016). In relation to
that, eye movement technology has been applied in
exploring the perceptual and the cognitive processes which are associated with autism, and tracking the
eyes provides an online measure of cognitive processing as they occur at
various tasks (Rayner, 2009). Benson et al.,
(2011) argues that the patterns of fixation provide
information on the existence of saccadic systems (see Appendix B) of
orientation. This provides inferences on
the significance of holding, as well as capturing attention in autism. The
technique of eye movement explores the major aspects of autism from past to
present. The first aspect is, the basic characteristics of oculomotor were examined using the low-level eye movement control. Another aspect
involves exploring eye movement in the perceptual processing of more complex
stimuli. The other aspects involve the
exploring of eye movement technique in providing insights of the social
impairments which are the most common characteristic of autism. These examinations of
aspects are important due to atypical eye movements may indicate of main processing
of problems per se, irrespective of social function, also there is some
evidence to offer that this may be the point of autism (Benson &
Fletcher-Watson, 2011).

In terms of
basic oculomotor control, the ET involves
the measurement of saccade amplitude, as well as the velocity. For instance; as
an initial experiment Rosenhall and colleagues investigated oculomotor
control in autism, this study includes 11 children with infantile autism or autistic-like conditions, the majority
of the participants with ASD exhibited velocities reduced at maximum as well as
saccadic positions of landing which fell short in locating the target (Rosenhall, Johansson,
& Gillberg, 1988).

On the
other hand, the measurement of the frequency in eye movement revealed that
individuals with ASD disorder showed more eye movements. Also, the language development is regarded as a modulating factor of autism,
in oculomotor controls (Benson & Fletcher-Watson,
2011).
With regard to the perceptual processing
of complex stimuli in autism, the eye movement method has identified a
relationship between the movement patterns with the imagination or flexibility
elements of autistic impairment triad when we compared to previous methods such
as, Visual search task and EFT, they had limited work on eye movement control in complex stimuli
tasks (Manjaly, Bruning, Neufang, Stephan, & Brieber,
2007). In the case of social impairments, ET shows that people with ASD
process face typically, for instance, participants
‘exhibits reduced fixation on major features of the face especially the eyes (Pelphrey, Sasson,
Reznick, & Paul, 2002).

Hence it is
concluded that the ET method remains
efficient in diagnosing autism disorder by analyzing and measuring different
sides of the autism.

Autism Diagnosis by Eye Tracking

The method
of ET was successful in detecting autism symptoms in infants at the age of six
months. Klin and Jones have developed a measure which was compounded by frames
and attention funnels (Klin and Jones, 2006). They first tracked a “typical”
two years age child’s eyes (sample size is 35). They then
tracked a two-year-old child with an autism disorder by letting them both watch a
video.

It was noted that the “typical” child focused on
the little scenes of fights in the video while the child with autism focused on
the opening and closing of the door in the same scenes. Klin and Jones then developed
a growth eye fixation chart or the focus percent of the eye for ages two,
three, four, five, six and nine months until the age of twenty-four months. It was observed
that typical children focused on peoples’ eyes initial times by the time it
remains stable. For babies with autism spectrum, it started high up and mild
orientation with people but no traction, then a free fall. They then used the
data to look six months’ infants and concluded that the eye fixation for the
two groups (the typical child and the child with autism disorder) could easily be separated. Also, that measure with other similar
measurements can be useful in identifying autism conditions early in life. When
compared to early times, it is thus not necessary to wait until a child is two
years old or more for autism disorders to emerge for diagnosis. Klin adds that
we need to provide this technology to clinics or hospitals; it needs to be
eligible for everyone because science has meaning if only it has utility for
society. However, the technique is relatively expensive and difficult to learn
as well. Not every person can work with eye trackers due to certain attributes
associated with it, such as long eyelashes.
It is also relatively difficult to interpret the data in this technique because
eye movements are often non-intentional.
Thus, careful interpretation is necessary to avoid unwanted user action
responses (Navalpakkam &
Churchill, 2014).Whereas;
the main point of tracking the eyes to reveal subconscious movement of an eye,
to providing objective measures rather than subjective ones thus
non-intentional movement can be considered as beneficial. In addition, ET allows us to quantify visual attention when we
compare to other techniques because as it objectively monitors what, when and
where people look at.

 Moreover, by ET, Klin and colleagues supported
their hypothesis by tracking the above, below or average attention in the
scenes which exist in children with autism and they made it possible to obtain
objects that are overlooked and ignored.

In terms
of diagnosing autism in infants, the study of ET in infants through corneal
reflections has been successful. It involved the study of gaze performances in
infants as well as estimation of gaze location with a high accuracy of infrared reflection. It’s
suggested that the early symptom of autism can be found in brain activity level
rather than behavioral level. Thus, in addition to Klin and Warren’s study, the
study by Chawarska et al.’s demonstrates that, behavioral signs of ASD
are present in early six months of age, which is suitable to the earliest age
that brain-based markers have been identified (Chawaska, Macari,
Dicinola, & Shic, 2016). The most positive aspect
of ET over other methods is that it has the ability to capture the dynamics of
gaze behavior, even though the experiment is conducted in complicated
environments. In a social interaction, correct timing of gaze is likely to be
critical, and a slight delay may mean missing important information, which will
reduce the observer’s chances to engage in meaningful interactions with other
people (Falck-Ytter, Bölte, &
Gredeback, 2013).

Outlook

We can
conclude that the ET technology is useful
in diagnosing autism spectrum for individuals, but especially for infants. Although
there are strengths about ET and autism predictive measures, some aspect of
autism remains to be explored. For instance, children with autism spectrum have
poor imitation and linguistic ability, but little research has been so far on
imitation capabilities and linguistic ability of children. Further goal needs to evaluate eye tracking in
terms of rehabilitation methods and diagnostic strategies to enrich both
literature and clinical settings (Kok & Jarodzka, 2016).