Description of the Neurovisual and Radiological Specificities of Patients With Visual Snow Syndrome (NEVICOG)

Description of the Neurovisual and Radiological Specificities of Patients With Visual Snow

NEVICOG is a single-center study evaluating neurovisual and radiological specificities in patients with visual snow syndrome (VSS) compared to a control population.

Study Overview

• Status: Withdrawn
• Conditions: Visual Snow Syndrome
• Intervention / Treatment: Procedure: Neurovisual evaluation; Procedure: Cerebral MRI

Detailed Description

Visual snow syndrome (SNV) is characterized by a continuous grainy or pixelated visual sensation additional to the perceived image. Patients often report a feeling similar to seeing noise from cathode-ray televisions.

The prevalence is not well known but about 2% of the population could be reached. Although benign and stable, this pathology is often troublesome in everyday life.

Its precise etiology remains unknown to this day. Ophthalmologic explorations do not reveal any significant abnormalities. Neurologically, "standard" examinations appear normal. Only the examinations carried out in the context of research have been able to highlight anomalies such as an imbalance between visual cortical inhibition and excitation as well as a high spontaneous neural triggering and hypermetabolism of the associative visual cortex (functional MRI, PET- MRI). In addition, the Visual Evoked Potentials show a lack of habituation, testifying to cortical hyperexcitability.

To our knowledge, no specific neurovisual study focusing on the functions involved in the processing of visual information has been carried out to date. We propose the realization of a complete evaluation made up of existing tasks as well as the adaptation of some of them specific to SNV.

The posterior abnormalities currently highlighted by imaging have been carried out in examinations not available on a daily basis. A non-invasive brain MRI study will be carried out in our patients using more recent techniques (MRI with arterial spin labelling or ASL for Arterial Spin Labelling, and diffusion tensor imaging or DTI for Diffusion Tensor Imaging) in order to search for possible posterior lesions and clinical radiological correlations.

Thus, this study aims to carry out a more in-depth neurovisual exploration of this syndrome, in order to allow a better understanding of this frequent and disabling disorder on a daily basis.

• Study Type: Observational

Contacts and Locations

Study Locations

• France
  • Paris, France, 75019
    • Hôpital Fondation A. de Rothschild

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: N/A
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients diagnosed with of visual snow syndrome according to international criteria compared to control patients without any visual snow syndrome

Description

Inclusion Criteria:

Case group:

• Patient aged up to 55
• Diagnosis of visual snow syndrome according to the international criteria
• Visual snow symptoms still present
• Express consent to participate in the study

Control group:

• Person aged up to 60
• Matched to an SNV patient on age (+/- 5 years) and sex
• Express consent to participate in the study

Exclusion Criteria:

Case group:

• Patient with an absolute or relative contraindication to MRI (claustrophobia, incompatible implantable device, etc.)
• Patient benefiting from a legal protection measure
• Pregnant or breastfeeding woman
• Non-French speaking patient
• Added psychiatric or neurodegenerative pathology unrelated to visual snow likely to induce neurocognitive and neurovisual disorders in the short or long term
• Ophthalmologic comorbidity that may interfere with the interpretation of examinations

Control group:

• Patient with an absolute or relative contraindication to MRI (claustrophobia, incompatible implantable device, etc.)
• Person benefiting from a legal protection measure
• Pregnant or breastfeeding woman
• Non-French speaking person
• Psychiatric or neurodegenerative pathology likely to induce neurocognitive and neurovisual disorders in the short or long term
• Ophthalmologic comorbidity that may interfere with the interpretation of examinations

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Case group; Patients with visual snow syndrome according to international criteria	Procedure: Neurovisual evaluation; Standardized tests and scales classically used during a neurovisual evaluation,; Procedure: Cerebral MRI; Sequences realized : 3D T1 TFE i1.0; 3D FLAIR i1.0; 2D T2 0.3 coro, centré sur les orbites; 3D T2 i0.6; SWIp 0.6; 3D PD T2 NO, centré sur les orbites; 3D ASL; DTI 64dir
Control group; Patients without visual snow syndrome according to international criteria	Procedure: Neurovisual evaluation; Standardized tests and scales classically used during a neurovisual evaluation,; Procedure: Cerebral MRI; Sequences realized : 3D T1 TFE i1.0; 3D FLAIR i1.0; 2D T2 0.3 coro, centré sur les orbites; 3D T2 i0.6; SWIp 0.6; 3D PD T2 NO, centré sur les orbites; 3D ASL; DTI 64dir

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Results of the neurovisual assessment	Rey-Osterrieth test will be used to assess the neurovisual ability. Patients have to reproduce a figure composed of 18 elements. A score between 0 and 2 is given to each of these elements according to their accuracy. The score varies from 0 to 36 and assesses the patient's visuo-constructive ability (36 corresponds to the best visuo-constructive ability).	1 day (Inclusion)

Collaborators and Investigators

• Sponsor: Fondation Ophtalmologique Adolphe de Rothschild
• Investigators: Principal Investigator: Nina Di Donato, Hôpital Fondation A. de Rothschild; Study Director: Romain Deschamps, MD, Hôpital Fondation A. de Rothschild

Study record dates

Study Major Dates

• Study Start (Anticipated): April 13, 2022
• Primary Completion (Anticipated): April 13, 2022
• Study Completion (Anticipated): April 13, 2022

Study Registration Dates

• First Submitted: September 10, 2021
• First Submitted That Met QC Criteria: February 7, 2022
• First Posted (Actual): February 8, 2022

Study Record Updates

• Last Update Posted (Actual): April 20, 2022
• Last Update Submitted That Met QC Criteria: April 13, 2022
• Last Verified: April 1, 2022

More Information

Terms related to this study

• Keywords: Visual Snow Syndrome
• Additional Relevant MeSH Terms: Pathologic Processes; Disease; Syndrome
• Other Study ID Numbers: NDO_2021_17

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No