The Strasbourg Visual Scale: A Novel Method to Assess Visual Hallucinations.
Anne Giersch, Thomas Huard, Sohee Park, Cherise Rosen
Frontiers in Psychiatry June 9, 2021 DOI: 10.3389/fpsyt.2021.685018 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Theoretical or philosophical paper Peer reviewed |
|---|---|
| Topics | Philosophy of mind |
| Keywords | Scale Hallucinations Visual perception Psychosis Imagery Verbal report |
| Key points | Proposes that the "Strasbourg Visual Scale (SVS)," a computerized step-by-step image-choice tool modeled on facial-composite generation, can capture the subjective content of visual hallucinations while circumventing the verbal-description difficulties often reported in psychosis, and argues it may complement existing scales. |
Abstract
The experience of oneself in the world is based on sensory afferences, enabling us to reach a first-perspective perception of our environment and to differentiate oneself from the world. Visual hallucinations may arise from a difficulty in differentiating one's own mental imagery from externally-induced perceptions. To specify the relationship between hallucinations and the disorders of the self, we need to understand the mechanisms of hallucinations. However, visual hallucinations are often under reported in individuals with psychosis, who sometimes appear to experience difficulties describing them. We developed the "Strasbourg Visual Scale (SVS)," a novel computerized tool that allows us to explore and capture the subjective experience of visual hallucinations by circumventing the difficulties associated with verbal descriptions. This scale reconstructs the hallucinated image of the participants by presenting distinct physical properties of visual information, step-by-step to help them communicate their internal experience. The strategy that underlies the SVS is to present a sequence of images to the participants whose choice at each step provides a feedback toward re-creating the internal image held by them. The SVS displays simple images on a computer screen that provide choices for the participants. Each step focuses on one physical property of an image, and the successive choices made by the participants help them to progressively build an image close to his/her hallucination, similar to the tools commonly used to generate facial composites. The SVS was constructed based on our knowledge of the visual pathways leading to an integrated perception of our environment. We discuss the rationale for the successive steps of the scale, and to which extent it could complement existing scales.
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| From dopamine to salience to psychosis--linking biology, pharmacology and phenomenology of psychosis. | 2005 | Theoretical or philosophical paper | |
| How do the brain's time and space mediate consciousness and its different dimensions? Temporo-spatial theory of consciousness (TTC). | 2017 | Theoretical or philosophical paper | |
| The phenomenology of deep brain stimulation-induced changes in OCD: an enactive affordance-based model. | 2013 | Theoretical or philosophical paper | |
| Looking for the Self: Phenomenology, Neurophysiology and Philosophical Significance of Drug-induced Ego Dissolution | 2017 | Theoretical or philosophical paper |
Citations in the library
Cites 23
- The Predictive Coding Account of Psychosis. Biological Psychiatry May 25, 2018
- What Geometric Visual Hallucinations Tell Us about the Visual Cortex Neural Computation March 1, 2002
- Self-disturbance and schizophrenia: structure, specificity, pathogenesis (Current issues, New directions). Schizophrenia Research 2014
- The Neurodynamic Organization of Modality-Dependent Hallucinations Cerebral Cortex April 24, 2012
- Dreams, Hallucinogenic Drug States, and Schizophrenia: A Psychological and Biological Comparison Schizophrenia Bulletin 1983
and 18 more in the library