The connection between the eyes and the brain is more profound than many realize. Emerging from common brain tissue during early development, eyes are the extension of the brain itself. Interestingly, the brain regions governing eye movements also intertwine with those regulating behaviors, emotions, and reasoning (Pouget, 2015).
Even subtle deviations from conventional eye movement patterns may signify underlying changes in brain activity (Maron et al., 2021). Leveraging this intricate relationship, eye tracking technology emerges as a non-invasive means of measuring eye positions and movements. Eye tracking holds potential in screening for brain health by monitoring where individuals focus while viewing visual stimuli.
Eye movements provide valuable insights into neurodevelopmental disorders like ADHD and autism, as well as age-related conditions such as Parkinson’s and Alzheimer’s, and learning challenges like dyslexia. In Tobii’s white paper
Eye tracking in neurology and psychiatry research you can dive deeper into a complete list of conditions that can be assessed with eye tracking.
Autism spectrum disorder (ASD) is characterized by a lack of engagement and interest in social interactions. Notably, one of the earliest indications of social disengagement in toddlers at risk of ASD is their response to ‘motherese’—a high-pitched, sing-songy voice often used by mothers when speaking to infants. Eye tracking can efficiently quantify the extent of attention paid to motherese.
Research has demonstrated that toddlers aged 12 - 48 months who pay attention to motherese less than 30% of the time could be accurately identified as having ASD
(Pierce et al., 2023). Similarly, other social attention stimuli, such as videos featuring people engaged in yoga versus moving geometric shapes, have shown promising accuracy in identifying ASD in high-risk toddlers (Wen et al., 2022).
ADHD is characterized by difficulty paying and sustaining attention in tasks and acting without foresight. These ADHD features, clinically known as inattention and impulsivity, typically start in childhood and often persist into adulthood. Impulsivity and inattention can be quantified using eye tracking tests. These tests typically involve stimuli that require participants to fixate their gaze, with the ability to do so in the presence of a distractor, revealing crucial insights into attention deficits.
Studies using eye tracking in children with ADHD have shown considerable potential, with accuracy rates of up to 77% in identifying affected children from typically developing peers (Yoo et al., 2024). Furthermore, combining existing ADHD assessment tests with eye tracking techniques can enhance diagnostic precision
(Lee et al., 2023).
In Alzheimer's disease, a gradual decline in brain function typically comes before full-blown symptoms like memory loss. Eye tracking tasks, which challenge individuals’ ability to remember and find items on a computer screen, have shown a high sensitivity and specificity in detecting mild declines in key brain functions early on
(Tokushige et al., 2023).
As further outlined in Tobii's white paper Eye tracking in neurology and psychiatry
research, various eye movement metrics such as the inability to control gaze deliberately and swiftly, are significantly linked to mild declines in brain function
(Opwonya et al., 2023). Early medical interventions can slow disease progression and improve affected individuals’ quality of life, but cost-effective and accessible disease screening is essential for this. Eye tracking shows promise in identifying early Alzheimer’s stages before more obvious symptoms emerge and could be a candidate for enabling a population-wide assessment.
Parkinson’s disease (PD), known primarily for its motor symptoms, also affects vision and eye movements. Clinical evaluations often reveal abnormalities in saccadic eye movements, the type of eye movement used to shift focus on objects of interest. In PD, saccades are inaccurate and fall short of their intended targets
(Shaikh & Ghasia, 2019). Regular assessment of eye movements enables healthcare professionals to monitor the progression of Parkinson’s over time.
Changes in eye movement patterns serve as indicators of disease severity and treatment efficacy, offering valuable insights into the evolving nature of these conditions. Additionally, although PD is mainly considered a movement disorder, over 80% of PD patients will develop a gradual decline in brain functions and eventually dementia (Hely et al., 2008). Therefore, similarly to Alzheimer’s disease, the timely identification of cognitive decline is crucial to allowing early intervention to be possible.
While some individuals excel as fast and proficient readers, others may struggle, particularly those with dyslexia—a learning disorder that impacts a person’s ability to read, write, and spell, often persisting into adulthood. Eye tracking studies show that children and adults with dyslexia typically take longer to scan words, move their eyes shorter distances, and exhibit fewer word-skipping behaviors while reading. These patterns may indicate challenges in quickly comprehending and accessing words in their minds, mainly when individuals spend more time fixating on the initial words on each line, suggesting an increased effort to understand them (Franzen et al., 2021).
Children diagnosed with dyslexia often require specialized learning techniques to manage their reading challenges effectively. Diagnosis typically involves conducting assessments, which can be either written or oral. Incorporating eye movement tracking into these assessments helps create a visual representation of key reading characteristics, enabling specialists to identify and address reading difficulties early in the learning process. Read more about eye tracking-based dyslexia assessment solutions developed in partnership with Lexplore.
Eye tracking is proven to be a powerful technology, offering a non-invasive means to assess brain health across different stages of life. From infancy to adulthood, eye movements provide valuable insights into neurodevelopmental disorders like ADHD and autism, as well as age-related conditions such as Parkinson’s and Alzheimer’s. Additionally, eye tracking aids in diagnosing specific learning challenges like dyslexia, highlighting its versatility in addressing a wide range of cognitive impairments.
By leveraging the intricate connection between the eyes and the brain, researchers and healthcare professionals are revolutionizing early detection, monitoring, and treatment evaluation of brain disorders, ultimately enhancing the quality of life for individuals worldwide.
Dive deeper into how eye movements are providing insights into various brain conditions and aiding early disease detection.
This is the SyncThink (now NeuroSync) story, and how they brought research connecting eye movements with brain trauma into a commercialized VR solution on the Pico Neo 2 Eye, with native Tobii eye tracking.
Scientists from the City College of New York, aimed to understand how a combination of visual changes affects brain activity while watching movies.
Download this white paper to learn the value of eye tracking in cognitive psychology and neuroscience research and how it is used to study selected cognitive functions like attention, memory, decision-making, problem-solving, or associative learning.
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