Abstract
The chapter intends to highlight the use of eye tracker, a tool that tracks eye movements, as a potential tool to aid diagnosis of specific learning disabilities along with psychometric tests. The issue of identifying and assessing children for specific learning disabilities is very difficult and crucial for the psychological, social, and personal wellbeing of the child growing into an adult. A common technique for diagnosing specific learning disabilities is the need of the hour. The eye is considered to be the window to the brain. Any differences in the eye movement can reflect disorders or diseases in the functional areas of cerebral cortex, brain stem, cerebellum, and other areas of the brain. The most important contribution of eye tracking research is it allows examination of different aspects of cognitive performance in moment-to-moment details on very simple tasks and infer the neurobiological basis of cognitive processes. Therefore, the chapter focuses on studies related to use of eye trackers as a futuristic technique in the diagnosis of specific learning disabilities.
TopIntroduction
The school failure and school dropouts have most of the time been the reason for children not being diagnosed with specific learning disabilities. Therefore, accurate diagnosis during early years of growth, though not an easy task, becomes the need of the hour. The traditional paper-based diagnostic tests for dyslexia are used in different parts of the world such as Diagnostescher Rechtschrieb test (Grund, Naumann, & Haug, 2004) for German, Wide-Range Achievement Test (Wilkinson, 1993) for English, and NIMHANS index of specific learning disabilities (Kapur, John, Rozario, & Oommen, 2002), analyze mostly reading and writing skills and confirm the diagnosis for dyslexia. These tests seem to have limitations because:
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They test the behavioral component, that is, the performance to predict the cognitive potential of the child.
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Need unbiased expert knowledge in interpreting results.
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Testing environment may affect the child’s level of functioning that may result in discrepancies in findings.
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They are language specific.
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Focus more on reading and the mathematical ability for diagnosis questioning the severity of cognitive dysfunction.
Eye tracking can be an important tool to aid diagnosis of learning disability for a diverse population. Eye trackers record eye movements to predict the cognitive skill/ability of the individual. One can observe and understand the pattern of eye movement through scan path and maps, the duration of time with fixations and saccades while moving the eye along the stimuli. It provides detailed data on the ease and difficulty of reading a text even the subtle difference of whether the text is given was difficult or the individual is finding it difficult and the level or extent of difficulty to read is very clear. It also gives detailed data as to the difference between reading a linguistic or non-linguistic task. Eye trackers are user-friendly and come in various forms from head-mounted to mobile eye trackers making it tailor-made for the specific use. One has to be trained for using and handling data collection for a couple of months to be able to use eye trackers as an aid for diagnosis. The data thus collected may be analyzed by expert psychologists thereby saving a lot of time for experts and providing time-locked online measurements for analysis of the specific level of cognitive functioning.
Research in the field of eye tracking as a tool for diagnosis has been picking up in western countries and has proven to be useful especially in the diagnosis of specific learning disabilities. Studies in India also reveal differences in eye movement pattern in children with specific learning disabilities especially in linguistic tasks as compared to non-linguistic tasks.
TopEye And The Visual System: A Window To The Brain
The most primitive, immediate and involuntary behavior witnessed in infants is to look. This is a major route to the child’s mind/brain functioning. Looking involves eye movement, when measured; provide insight into a child’s spatial and temporal perception of his/her world. It is almost effortless and natural for humans to take the world through the eye. In fact, we live in a visual world perceiving almost everything through the eye and comprehending through the brain. Eye movements are considered to be the window to the brain hence a way to understand/ study cognitive abilities of an individual to perceive, recognize and comprehend the world around him/her. It is quite natural that we look at the most relevant and interesting part of an object/text/image necessary to recognize and comprehend and therefore move our eyes only to those selective areas. Furthermore, the pupil of the eye not only moves to extract information, decide where to see but also dilate rapidly to an array of cognitive and emotional stimuli thus revealing a great deal about processes like recognition, cognitive abilities, memory, thinking, feelings, learning, comprehension, socio-emotional and many other cognitive processes.
Key Terms in this Chapter
Calibration: It is a process whereby the participant’s eye is synchronized to the eye tracker’s camera. The participant is instructed to follow points displayed so as to estimate the geometric characteristics of the participant’s eye. The accuracy of data collected depends on the exactness of the calibration.
Diagnosis: The process of identifying an illness, disorder or disability based on the presenting symptoms.
Specific Learning Disabilities: A disorder in more than one of any psychological processes with regard to learning to read, write or comprehend due to imperfection in cognitive ability.
Reading Paradigm: It is simple sentence reading paradigm, wherein participants will have to read the sentences while eye movement measures are recorded online. The stimulus will be a sentence with a target word embedded in a destined position as per the research requirement.
Saccades: The movement of the eye from one area to another area of a stimulus to bring it to the foveal vision is said to be a saccade.
Visual World Paradigm: It is an experimental paradigm wherein participants hear utterances while looking at a visual display of target word along with competitors and distracters on the visual display. The task assigned to the participants is usually to look and listen.
Eye Tracker: It is a tool that has built-in cameras and enables online recording of eye movements.
Moving Window or Gaze-Contingent Paradigm: A paradigm in which the stimulus display changes depending on where the participant looks.
Visual System: The ability of the eye and the central nervous system to process the visual world around us. It’s the ability to detect, interpret and comprehend a given stimulus.