Visual scan paths in young patients with schizophrenia, healthy siblings and controls

Free viewing exploration in schizophrenia: Review of evidence from laboratory settings to natural environment

Several studies have investigated visual processing impairment in schizophrenia. The literature on visual exploration has described restricted scanning in schizophrenia patients. This gaze behavior is characterized by increased fixation duration, a reduced scan path length and avoidance of salient features of the face with emotional content. The aim of this paper is to give an insight on the latest update on scan path deficit. Abnormal gaze exploration was replicated in various visual stimuli. This review describes gaze patterns with stimuli that imply minimal to high cognitive process: figures, objects, faces, and scenes. Interestingly, schizophrenia patients have shown cognitive flexibility by modulating gaze scanning when they are involved in an active assignment. We will also consider scanning abnormalities in real-life environment and discuss the potential therapeutic use of eye tracking in schizophrenia. The therapeutic application of eye tracking in schizophrenia is a young emerging field in psychiatry research. The recent remediation program is based on the reorientation of visual attention on the salient features of faces. For now, this program has shown encouraging results. Further studies are needed to explore behavior in real-world situations to complement laboratory measurements to move toward a full understanding of the mechanisms underlying atypical scanning in patients with schizophrenia.

Facial affect recognition in body dysmorphic disorder versus obsessive-compulsive disorder: An eye-tracking study

BACKGROUND

Body dysmorphic disorder (BDD) is characterised by repetitive behaviours and/or mental acts occurring in response to preoccupations with perceived defects or flaws in physical appearance (American Psychiatric Association, 2013). This study aimed to investigate facial affect recognition in BDD using an integrated eye-tracking paradigm.

METHOD

Participants were 21 BDD patients, 19 obsessive-compulsive disorder (OCD) patients and 21 healthy controls (HC), who were age-, sex-, and IQ-matched. Stimuli were from the Pictures of Facial Affect (Ekman & Friesen, 1975), and outcome measures were affect recognition accuracy as well as spatial and temporal scanpath parameters.

RESULTS

Relative to OCD and HC groups, BDD patients demonstrated significantly poorer facial affect perception and an angry recognition bias. An atypical scanning strategy encompassing significantly more blinks, fewer fixations of extended mean durations, higher mean saccade amplitudes, and less visual attention devoted to salient facial features was found.

CONCLUSIONS

Patients with BDD were substantially impaired in the scanning of faces, and unable to extract affect-related information, likely indicating deficits in basic perceptual operations.

Smooth pursuit and visual scanpaths: Independence of two candidate oculomotor risk markers for schizophrenia

OBJECTIVES

Smooth pursuit and visual scanpath deficits are candidate trait markers for schizophrenia. It is not clear whether eye tracking dysfunction (ETD) and atypical scanpath behaviour are the product of the same underlying neurobiological processes. We have examined co-occurrence of ETD and scanpath disturbance in individuals with schizophrenia and healthy volunteers.

METHODS

Eye movements of individuals with schizophrenia (N = 96) and non-clinical age-matched comparison participants (N = 100) were recorded using non-invasive infrared oculography during smooth pursuit in both predictable (horizontal sinusoid) and less predictable (Lissajous sinusoid) conditions and a free viewing scanpath task.

RESULTS

Individuals with schizophrenia demonstrated scanning deficits in both tasks. There was no association between performance measures of smooth pursuit and scene scanpaths in patient or control groups. Odds ratios comparing the likelihood of scanpath dysfunction when ETD was present, and the likelihood of finding scanpath dysfunction when ETD was absent were not significant in patients or controls in either pursuit variant, suggesting that ETD and scanpath dysfunction are independent anomalies in schizophrenia.

CONCLUSION

ETD and scanpath disturbance appear to reflect independent oculomotor or neurocognitive deficits in schizophrenia. Each task may confer unique information about the pathophysiology of psychosis.

Current visual scanpath research: a review of investigations into the psychotic, anxiety, and mood disorders

The human visual system is comprised of an array of complex organs, which jointly decode information from visible light to construct a meaningful representation of the surrounding environment. The study of visual scanpaths transpired in a bid to enhance our understanding of the role of eye movements underpinning adaptive functioning as well as psychopathology and was further aided by the advent of modern eye-tracking techniques. This review provides a background to the nature of visual scanpaths, followed by an overview and critique of eye movement studies in specific clinical populations involving the psychotic, anxiety, and mood disorders, and concludes with suggested directions for future research. We performed a Medline and PsycInfo literature search, based on variations of the terms "visual scanpath," "eye-tracking," and "eye movements," in relation to articles published from 1986 to the present. Eye-tracking studies in schizophrenia mostly concurred with the existence of a "restricted" scanning strategy, characterized by fewer number of fixations of increased durations, with shorter scanpath lengths, and a marked avoidance of salient features, especially in relation to facial emotion perception. This has been interpreted as likely reflecting dual impairments in configural processing as well as gestalt perception. Findings from the anxiety and mood disorders have conversely failed to yield coherent results, with further research warranted to provide corroborating evidence and overcome identified methodological limitations. Future studies should also look toward applying similar techniques to related disorders as well as conducting parallel neuroimaging investigations to elucidate potential neurobiological correlates.

Clair DM, Benson PJ. Atypical scanpaths in schizophrenia: evidence of a trait- or state-dependent phenomenon?

The development of trait markers of schizophrenia would represent an important advance in understanding the genetic architecture of the disease. To date, no candidate markers have satisfied all of the trait marker criteria, and many are not specific to the schizophrenia spectrum. Abnormalities in visual scanpaths are frequently reported in patients with schizophrenia and are emerging as a novel candidate for a schizophrenia biomarker. Here we review the suitability of scanpath measures as a target for trait marker research in schizophrenia. Papers reporting scanpath patterns in patients with schizophrenia were identified by PubMed and Google Scholar searches and by scanning reference lists in relevant articles. Search terms included "schizophrenia," "psychosis," "scanpath," "scan path," "fixation," "saccade" and "eye movement." Scanpath abnormalities afford impressive sensitivity and specificity and appear largely independent of psychotropic medications. Scanpaths may demonstrate some fluctuation with symptomatology and may be useful in illuminating illness state or subtypes. However, there is evidence that viewing behaviours remain atypical regardless of symptom remission and may be present in unaffected relatives of individuals with schizophrenia. This research is in its early stages, and further investigation regarding patterns of inheritance is required. Our findings support scanpath measures as a favourable topic for further investigation as a trait marker.