NCT03188133

Visual Information Processing in Schizophrenia Patients With Visual Hallucinations

Top Down Visual Information Processing in Schizophrenia Patients With Visual Hallucinations

• Status: Unknown
• Phase: N/A
• Study type: Interventional
• Enrollment: 90 (estimated)
• Sponsor: Central Hospital, Nancy, France · Academic / Other
• Sex: All
• Age: 18 Years – 55 Years
• Healthy volunteers: Accepted

Summary

Occurrence of visual hallucinations (VHs) in schizophrenia depend in part on disorders in the processing of late visual information (Top-Down). The broader question of how these top-down mechanisms (cognitive and / or emotional mechanisms) are involved in the occurrence of VHs remains to be specified and very few behavioral studies have so far been interested. The investigators propose to study the implication of Top-Down mechanisms in the visual hallucinatory manifestations, more specifically in the processing of ambiguous stimuli during an emotional priming task. Schizophrenia patients with VHs would have more false visual perceptions in the treatment of ambiguous stimuli than schizophrenia patients with auditory hallucinations or no hallucinations (AH/NH) and healthy controls.

Detailed description

In schizophrenia patients with auditory hallucinations, top-down mechanism on perceptual processing could be illustrated by tasks of listening to white noise. These studies show that psychotic subjects detect more words and phrases when exposed to these stimuli. In schizophrenia patients with VHs, to our knowledge no study have explored the mechanism of false perception. Thus, we propose to experimentally manipulate the implication of Top-Down mechanisms on visual perception using an emotional priming task. This paradigm has already been used in this population to explain the mechanisms underlying productive symptoms. For example, in an emotional priming task authors have shown that a negative valence primer contributes to the implementation of an interpretive bias in a confidence judgment task. The aim of the present study is to explore the implication of these Top-Down mechanisms in hallucinatory manifestations, more specifically on the treatment of ambiguous visual stimuli during an emotional priming task by manipulating the emotional valence of the primer. The goal is to determine how emotional environmental elements contribute to the formation of erroneous perceptions in patients with schizophrenia with VHs.

Conditions

• Schizophrenia
• Visual Hallucination
• Auditory Hallucination
• False Perception

Interventions

Type	Name	Description
OTHER	behavioral task : emotional priming	emotional priming task on ambiguous visual stimuli

Timeline

• Start date: 2017-10-17
• Primary completion: 2018-05-01
• Completion: 2020-10-31
• First posted: 2017-06-15
• Last updated: 2017-10-09