Visual integration dysfunction in schizophrenia arises by the first psychotic episode and worsens with illness duration.

Abstract

Visual integration dysfunction characterizes schizophrenia, but prior studies have not yet established whether the problem arises by the first psychotic episode or worsens with illness duration. To investigate the issue, we compared chronic schizophrenia patients (SZs), first episode psychosis patients (FEs), and well-matched healthy controls on a brief but sensitive psychophysical task in which subjects attempted to locate an integrated shape embedded in noise. Task difficulty depended on the number of noise elements co-presented with the shape. For half of the experiment, the entire display was scaled down in size to produce a high spatial frequency (HSF) condition, which has been shown to worsen patient integration deficits. Catch trials—in which the circular target appeared without noise—were also added so as to confirm that subjects were paying adequate attention. We found that controls integrated contours under noisier conditions than FEs, who, in turn, integrated better than SZs. These differences, which were at times large in magnitude (d=1.7), clearly emerged only for HSF displays. Catch trial accuracy was above 95% for each group and could not explain the foregoing differences. Prolonged illness duration predicted poorer HSF integration across patients, but age had little effect on controls, indicating that the former factor was driving the effect in patients. Taken together, a brief psychophysical task efficiently demonstrates large visual integration impairments in schizophrenia. The deficit arises by the first psychotic episode, worsens with illness duration, and may therefore serve as a biomarker of illness progression.

Deconstructing eye contact perception: Measuring perceptual precision and self-referential tendency using an online psychophysical eye contact detection task

“…For example, temporary or situation-dependent factors that add perceptual noise (e.g., due to distance or lighting intensity [17]) can reduce the precision of gaze perception, and those that evoke a self-related belief (e.g., when one's name is being called [18]) can increase the likelihood of perceiving selfdirected gaze. Additionally, in psychiatric disorders in which abnormal gaze perception is well-documented (e.g., schizophrenia, ASD, and social anxiety), a large body of evidence also suggests disruptions in either/both visual perception and/or self-referential processing (e.g., dysfunction in low-level visual processing in ASD [19]; dysregulated self-referential tendencies in social anxiety [20,21]; deficits in both low-level visual processing [22,23] and higher-level self-referential processes [24] in schizophrenia). Therefore, dissociating these two cognitive processes can help us identify the sources of deficits underlying abnormal gaze perception in different psychiatric disorders as well as understand individual differences across the healthpsychopathology continuum.…”

Space and Objects: On the Phenomenology and Cognitive Neuroscience of Anomalous Perception in Schizophrenia (Ancillary Article to EAWE Domain 1)

“…Over 60 laboratory studies have demonstrated reduced perceptual organization in schizophrenia [9][10][11] . These abnormalities arise by the first psychotic episode and become more pronounced with increasing chronicity [11] .…”

“…These abnormalities arise by the first psychotic episode and become more pronounced with increasing chronicity [11] . They have not been found in other psychiatric disorders 1 [12][13][14][15][16] , and, among people with schizophrenia, they are associated with histories of poor premorbid functioning, disorganized symptoms, and poorer treatment response, suggesting they are an aspect of a more severely ill patient subtype [17] .…”

Poorer Integration of Local Orientation Information Occurs in Students With High Schizotypal Personality Traits

“…Threshold performance on this task reflects the amount of orientation noise that can be tolerated when making these judgments. Although this task has received strong research interest, and consistently revealed poorer performance in schizophrenia patients [e.g., ( 14 – 17 )], as early as the first psychotic episode ( 18 ), much less is known about these particular integration abilities in healthy individuals with high levels of schizotypy, who are at increased risk for schizophrenia.…”

“…Building on prior research, we chose to focus on positive schizotypy, comparing visual integration abilities in healthy individuals with high and low scores on the Perceptual Aberrations (PAb) scale ( 36 ). Based on previous evidence [e.g., ( 14 , 18 , 21 , 22 )] we predicted that, compared to the Low PAb group, the High PAb group would exhibit poorer tolerance to local noise (lower thresholds and lower proportion of correct responses on the RFJOT task) and reduced global integration efficiency (shallower slope values on the RFIT). In addition, in order to address the issue of specificity, the influence of other positive, disorganization and negative schizotypy traits was also explored.…”