Eye movement as a biomarker of schizophrenia: Using an integrated eye movement score

Abstract

Aim: Studies have shown that eye movement abnormalities are possible neurophysiological biomarkers for schizophrenia. The aim of this study was to investigate the utility of eye movement abnormalities in identifying patients with schizophrenia from healthy controls.Methods: Eighty-five patients with schizophrenia and 252 healthy controls participated in this study. Eye movement measures were collected from free viewing, fixation stability, and smooth pursuit tests. In an objective and stepwise method, eye movement measures were extracted to create an integrated eye movement score. Results:The discriminant analysis resulted in three eye movement measures; the scanpath length during the free viewing test, the horizontal position gain during the fast Lissajous paradigm of the smooth pursuit test, and the duration of fixations during the far distractor paradigm of the fixation stability test. An integrated score using these variables can distinguish patients with schizophrenia from healthy controls with 82% accuracy. The integrated score was correlated with Wechsler Adult Intelligence Scale-Third Edition full scale IQ, Positive and Negative Syndrome Scale scores, and chlorpromazine equivalents, with different correlation patterns in the three eye movement measures used. The discriminant analysis in subgroups matched for age, sex, years of education, and premorbid IQ revealed a sustained classification rate. Conclusion:We established an integrated eye movement score with high classification accuracy between patients with schizophrenia and healthy controls, although there was a significant effect of medication. This study provides further evidence of the utility of eye movement abnormalities in schizophrenia pathology and treatment.

Eye‐movement characteristics of schizophrenia and their association with cortical thickness

“…Many endophenotypes, such as eye‐movement characteristics and brain structural changes, are known in schizophrenia (SCZ). Eye movements serve as an output of cognitive processing and better performance has been associated with better social functioning in SCZ .…”

“…Data of 102 participants with SCZ and 341 healthy controls were analyzed (Table S1). We focused on three eye‐movement measures (scanpath length, horizontal position gain, and duration of fixations) and a score integrating these three measures . The respective associations between these measures and the cortical thickness of 34 bilateral regions based on the Desikan–Killiany atlas were tested.…”

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

“…One important factor concerning schizophrenia is the effect of antipsychotic agents . The effect of dopamine blockade associated with antipsychotic agents is known to affect muscle movements, causing extrapyramidal symptoms such as parkinsonism, dystonia, and dyskinesia.…”

Comparison of eye movements in schizophrenia and autism spectrum disorder

“…Discovery of disease‐specific biomarkers or behavioral indicators with sufficient sensitivity is an important issue to improve the clinical diagnosis of mental illness. Magnetic resonance images, near‐infrared spectroscopy, genetic markers, cognitive functions, and eye movements are candidates . Of them, eye movement is representative of sensorimotor functions of the brain, and eye movement abnormalities have been reported in subjects with schizophrenia .…”

“…Of them, eye movement is representative of sensorimotor functions of the brain, and eye movement abnormalities have been reported in subjects with schizophrenia . It has been frequently reported that subjects with schizophrenia can be successfully distinguished from healthy individuals by using eye movements . However, it is unknown whether the eye movement abnormalities that distinguish subjects with schizophrenia from healthy individuals are also effective in discrimination from other psychiatric disorders, such as autism spectrum disorder (ASD), which is a neurodevelopmental condition in which affected individuals have difficulties in social interactions and communications .…”