This document discusses using eye tracking tests to detect cognitive impairment. It begins by defining cognitive impairment and explaining its prevalence and costs. It then describes how eye trackers work by tracking eye movements and gaze. Analysis of eye tracking data can reveal indicators of cognitive impairment, such as slower reading speed, difficulty recognizing objects, and increased pupil dilation during visual tasks. However, eye movements alone do not provide full context of cognitive processes and have limitations in inferring specific cognitive events. Overall, eye tracking shows promise as a method for detecting cognitive impairment.

1. EYE TRACKING TESTS FOR
COGNITIVE IMPAIRMENT
Priyanka Bhojwani

2. AGENDA
What is Cognitive Impairment?
What is Eye-Tracking?
Interpretation of Eye Tracking Data
The Relationship between Eye Tracking & Cognitive Processes
Indicators of Cognitive Impairment through Eye Tracking
Example of an Eye Tracking Test
Limitations

3. WHY SHOULD WE CARE?
• Cognitive impairment is when a person has trouble remembering, learning new
things, concentrating, or making decisions that affect their everyday life.
• More than 16 million people in the United States are living with cognitive
impairment
• Age is the greatest risk factor for cognitive impairment
• Cognitive impairment is costly. People with cognitive impairment report more than
three times as many hospital stays as individuals who are hospitalized for some
other condition
• Individuals may reduce the risk of cognitive impairment by keeping physically active
and maintaining healthy cholesterol and blood sugar levels

4. WHAT IS EYE – TRACKING?
• In the simplest terms, eye tracking is the measurement of eye activity
• Eye tracking data is collected using either a remote or head-mounted ‘eye tracker’
connected to a computer
• generally include two common components: a light source and a camera. The light
source (usually infrared) is directed toward the eye. The camera tracks the reflection
of the light source along with visible ocular features such as the pupil.
• This data is used to extrapolate the rotation of the eye and ultimately the direction
of gaze

6. INTERPRETATION OF EYE TRACKING
DATA
Most Common Method:
• analyze the visual path of one or more participants across an interface such as a
computer screen.
• Each eye data observation is translated into a set of pixel coordinates.
• From there, the presence or absence of eye data points in different screen areas can
be examined
• This type of analysis is used to determine which features are seen, when a particular
feature captures attention, how quickly the eye moves, what content is overlooked
and virtually any other gaze-related question

7. THE RELATION BETWEEN EYE TRACKING
& COGNITIVE PROCESSES
• Eye movements in reading have long been a focus of research because of the
regularity of fixation patterns and the tight link between fixations and
comprehension (Rayner, 1998).
• The fixation patterns on a picture were fundamentally different when observers were
trying to answer different questions about the picture (Yarbus,1967)

8. INDICATORS OF COGNITIVE
IMPAIRMENT THROUGH EYE TRACKING
Some studies have been showing that patients with MCI:
• Have difficulty processing color information (http://www.ncbi.nlm.nih.gov/pubmed/10838150/)
• Demonstrate slow pursuit movements (http://www.ncbi.nlm.nih.gov/pubmed/3340292/)
• Show reduced contrast sensitivity (http://www.ncbi.nlm.nih.gov/pubmed/15842071/)
• Decreased reading speed (http://www.ncbi.nlm.nih.gov/pubmed/15842071/ )
• Impaired face or object recognition
(http://www.ncbi.nlm.nih.gov/pubmed/17941352/)
• Increased pupil dilation during a visual search, indicating increased effort
(http://www.ncbi.nlm.nih.gov/pubmed/19595301/ )

10. LIMITATIONS
• Fixations do not reveal much more than that the observer attended to these
locations
• Fixation duration is thought to correspond to cognitive processing ease or difficulty
but in scene perception research, out of context objects generate longer fixations
• The experimenter has little control of, and does not know, what the observer is
doing, and consequently inferences are limited.
• Therefore a given cognitive event might reliably lead to a particular fixation, the
fixation itself does not uniquely specify the cognitive event. (Viviani, 1990)

11. REFERENCES
• Centers for Disease Control & Prevention. (2011). Cognitive Impairment: A Call for Action
Now! Centers for Disease Control & Prevention.
• Pereira, M. L., Camargo, M. v., Aprahamian, I., & Forlenza, O. V. (2014). Eye movement
analysis and cognitive processing: detecting indicators of conversion to Alzheimer’s disease.
Neuropsychiatric Disease & Treatment.
• Rayner, K. (1998). Eye Movements in Reading & Information Processing: 20 years of research.
Psychological Bulletin.
• Yarbus, A. L. (1967). Eye Movements During Perception of Complex Objects. In A. L. Yarbus,
Eye Movements & Vision (pp. 171-211). Springer.