Application of eye trackers for understanding mental disorders: Cases for schizophrenia and autism spectrum disorder

Abstract

Studies of eye movement have become an essential tool of basic neuroscience research. Measures of eye movement have been applied to higher brain functions such as cognition, social behavior, and higher‐level decision‐making. With the development of eye trackers, a growing body of research has described eye movements in relation to mental disorders, reporting that the basic oculomotor properties of patients with mental disorders differ from those of healthy controls. Using discrimination analysis, several independent research groups have used eye movements to differentiate patients with schizophrenia from a mixed population of patients and controls. Recently, in addition to traditional oculomotor measures, several new techniques have been applied to measure and analyze eye movement data. One research group investigated eye movements in relation to the risk of autism spectrum disorder several years prior to the emergence of verbal‐behavioral abnormalities. Research on eye movement in humans in social communication is therefore considered important, but has not been well explored. Since eye movement patterns vary between patients with mental disorders and healthy controls, it is necessary to collect a large amount of eye movement data from various populations and age groups. The application of eye trackers in the clinical setting could contribute to the early treatment of mental disorders.

Recent updates of eye movement abnormalities in patients with schizophrenia: A scoping review

“…Therefore, an eye‐tracking tool introduces a significant promise of accessibility. Also, in the light of a noticeable shift in focus of research in the SZ spectrum from classical symptomatology to context‐processing impairments 2, 18–23 and cognitive remediation for treating cognitive dysfunction, 24–28 the study of cognitive impairments has become a high‐priority area of interest. Finally, following the line of evidence that vision in SZ does matter, 29 an intriguing trend to study the visual processing structure by re‐examining paradigms with the inclusion of modern eye‐tracking devices started to emerge 30 …”

“…Importantly, perception deficits seem to persist exclusively (selectively) in SZ. Therefore, in recent years, some independent research groups have started to actively record eye movements to differentiate patients with SZ from HC 23, 42, 54, 117, 219, 238, 263–265 . Such an approach marks a new beginning of promising continuous years of research on visual disturbances in SZ patients, with eye‐tracking technology revolutionizing mental health screening, even with the use of one's smartphone 266–268 .…”

Interpretable Machine Learning Models for Three-Way Classification of Cognitive Workload Levels for Eye-Tracking Features

“…Eye activity-related and DSST test results-related data exported from the eye tracker covering 20 features are presented below: The listed eye-activity related features were chosen as the most informative ones available in the eye tracker software. Features related to fixations and saccades are the most common eye-tracking features analysed in the literature [54] in such areas as psychology and neuroscience, including behavioural patterns, mental fatigue, and disorders analysis [46,57]. Although in the literature the most common approaches consider only the main fixation-and saccade-related features such as the total number of saccades, mean duration of saccades, total number of blinks, and mean of blink duration, we decided to consider also an additional set of features including standard deviation of saccades amplitude, standard deviation of fixation duration, maximum and minimum saccade amplitude, and fixation duration.…”

“…Fixations and saccades are detected in the Tobii Studio with the Velocity–Threshold Identification (I-VT) fixation classification algorithm [ 57 ], which classifies the eye movements using directional velocity shifts of the eye. The velocity threshold parameter was set to 30°/s [ 58 ].…”

The inter-relationships between cerebral visual impairment, autism and intellectual disability

“…Faced with the frequency of visual dysfunction in subjects with ASD, it is also possible that underlying oculomotor deficits (Shishido et al, 2019) or CVI could significantly contribute to the clinical picture of ASD and to associated deficits (i.e. ID).…”