Visual Information Processing in Schizophrenia Patients With Visual Hallucinations (SHALL)

October 6, 2017 updated by: Central Hospital, Nancy, France

Top Down Visual Information Processing in Schizophrenia Patients With Visual Hallucinations

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.

Study Overview

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.

Study Type

Interventional

Enrollment (Anticipated)

90

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 53 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

All Groups:

  • Age between 18 and 55 years
  • Affiliation to or benefiting from a social security
  • Visual acuity normal or corrected to normal
  • Person who received and understood the complete information about the organization of the research and gave written and free informed consent before participating in the study

Group of patients with schizophrenia with visual hallucination (HV) with or without auditory hallucination (HA) (HV group):

  • Schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders IV criteria
  • Presence of a hallucinatory visual symptomatology (HV) in the history of the disease measured by the Psychosensory hallucination scale (PSAS).
  • The presence of a hallucinatory symptomatology in auditory mode (HA) in addition to the HV is not a criterion of non-inclusion.

Group of patients with schizophrenia either with auditory hallucination (HA) but without visual hallucination (HV) or no hallucination, auditory or visual (NH) (HA / NH group)

  • Schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders IV criteria
  • Presence of a hallucinatory symptomatology in auditory mode (HA) in the history of the disease measured by the PSAS or absence of any hallucinatory manifestations in the history of the disease
  • Absence of visual hallucinatory symptomatology (HV) in the history of the disease as measured by PSAS

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: VH
schizophrenia patients with visual hallucinations
emotional priming task on ambiguous visual stimuli
Active Comparator: AH/NH
schizophrenia patients with auditory hallucinations or no hallucinations
emotional priming task on ambiguous visual stimuli
Active Comparator: C
healthy controls
emotional priming task on ambiguous visual stimuli

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of false visual perception on the emotional priming task
Time Frame: through study completion an average of 6 months
Number of false perception made by participants on an ambiguous visual stimulus i.e when a participant identifies incorrectly an ambiguous stimulus as a genuine percept (for example a participant sees a face in a noisy grey pattern)
through study completion an average of 6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
number of false visual perception on the emotional priming task depending of the emotional valence manipulated
Time Frame: through study completion an average of 6 months
The investigators will investigate if the manipulated valence of the emotional priming task influences the number of false visual perceptions of ambiguous stimuli
through study completion an average of 6 months
Cognitive performances at the neuropsychological assessment
Time Frame: through study completion an average of 6 months
Cognitive performances at the neuropsychological assessment conducted for both groups of schizophrenia patients. Neuropsychological assessment will provide performance scores on different cognitive functions : episodic memory (California Verbal Learning Test), visual memory (delayed match to sample task), working memory (forward and backward digit span, n-back task), sustained attention (test of attentional performance battery), divided attention (test of attentional performance battery), inhibition (test of attentional performance battery), processing speed (coding) and visual perception and processing (visual object space perception task).
through study completion an average of 6 months
Psychosensory hallucinations scale scores
Time Frame: through study completion an average of 6 months
scores on the Psychosensory hallucinations scale conducted for both schizophrenia patients groups. This scale provides a complete evaluation of hallucinations in all modalities as well as the impact of these symptoms on daily life.
through study completion an average of 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Vincent LAPREVOTE, Central hospital Nancy, Centre Psychothérapique de Nancy

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Anticipated)

October 17, 2017

Primary Completion (Anticipated)

May 1, 2018

Study Completion (Anticipated)

October 31, 2020

Study Registration Dates

First Submitted

June 9, 2017

First Submitted That Met QC Criteria

June 14, 2017

First Posted (Actual)

June 15, 2017

Study Record Updates

Last Update Posted (Actual)

October 9, 2017

Last Update Submitted That Met QC Criteria

October 6, 2017

Last Verified

October 1, 2017

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Schizophrenia

Clinical Trials on behavioral task : emotional priming

3
Subscribe