UnReal? Investigating the Sense of Reality and Psychotic Symptoms with Virtual Reality.

Gad Drori,Yair Zvilichovsky,Yonatan Stern,Roy Salomon,Paz Bar-Tal

doi:10.3390/jcm9061627

Gad Drori, Yair Zvilichovsky + Show 3 more

Open Access

https://doi.org/10.3390/jcm9061627

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Abstract

Distortions of reality, such as hallucinations, are common symptoms of many psychiatric conditions. Accordingly, sense of reality (SoR), the ability to discriminate between true and false perceptions, is a central criterion in the assessment of neurological and psychiatric health. Despite the critical role of the SoR in daily life, little is known about how this is formed in the mind. Here, we propose a novel theoretical and methodological framework to study the SoR and its relation to psychotic symptoms. In two experiments, we employed a specialized immersive virtual reality (VR) environment allowing for well-controlled manipulations of visual reality. We first tested the impact of manipulating visual reality on objective perceptual thresholds (just noticeable differences). In a second experiment, we tested how these manipulations affected subjective judgments of reality. The results revealed that the objective perceptual thresholds were robust and replicable, demonstrating that SoR is a stable psychometric property that can be measured experimentally. Furthermore, reality alterations reduced subjective reality judgments across all manipulated visual aspects. Finally, reduced sensitivity to changes in visual reality was related to self-reported prodromal psychotic symptoms. These results provide evidence for the relevance of SoR in the assessment of psychosis and other mental disorders in which reality is distorted.

Highlights

Abnormal sense of reality (SoR) processing may lead to a disparity between experience and reality, resulting in hallucinations, which is a core symptom of psychosis
We hypothesized that psychophysical measures of sensory processing (JNDs) would be stable within participants, demonstrating that SoR exhibits robust psychometric properties. We examined whether these measures of SoR are correlated to self-reported prodromal psychotic symptoms, especially for manipulations of the self that are known to be linked to schizophrenia spectrum psychosis [25,27,45]
The present study investigated the SoR and its relation to psychotic symptoms

Summary

Introduction

We normally and intuitively trust our sensory representation of the world to closely correspond to what “is really there” [1,2] We term this correspondence “reality”, and differentiate it from other states in which our representations of the world do not match the environment, such as dreaming and hallucinations. We seem to possess a capacity to judge whether our sensory experience corresponds to the world or not, i.e., a sense of reality (SoR). This capacity is a critical aspect of the human mind, allowing us to guide our actions based on meaningful sensory signals. While SoR is an important criterion in the assessment of neurological and psychiatric health [3,4,5], we know little regarding its underlying cognitive mechanisms

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