Anti-Extinction in Patients With Schizophrenia

Patients with schizophrenia demonstrate visual processing impairments; however, the nature of these impairments remains undetermined.
The present study aimed at investigating the visual processing of unilateral compared to bilateral visual stimuli in these patients.
A group of 27 schizophrenia patients and a group of 27 matched controls (age, gender, education level and hand preference) (20 males in each group), were tested in 2 computerized tasks, namely circle and star and triangle. Unilateral and bilateral shapes were presented on the screen of a computer. In the circle task, stimuli were similar unilateral left, unilateral right and bilateral circles that appeared on a computer screen, whereas in the star and triangle task, there were different unilateral and bilateral stimuli. Participants were instructed to press the left key in unilateral and right key in bilateral trials.
In both tasks, the patients significantly detected bilateral displays more accurately than unilateral displays, and unilateral-left more accurately than unilateral-right trials. The similarity of stimuli on the star and triangle task, did not affect the patients’ performance. In contrast, individuals in the control group performed similarly across both unilateral and bilateral trials.
These findings provide evidences of hemineglect and anti-extinction in patients with schizophrenia, suggesting bilateral advantage in visuospatial processing in the patients.