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

Visual Snow Syndrome Clinical Trial

— NEVICOG  

Official title:

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

Clinical Trial Details — Status: Withdrawn

Administrative data

• NCT number: NCT05229731
• Other study ID #: NDO_2021_17
• Status: Withdrawn
• Start date: April 13, 2022
• Est. completion date: April 13, 2022

Study information

• Verified date: April 2022
• Source: Fondation Ophtalmologique Adolphe de Rothschild
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

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

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.

Recruitment information / eligibility

• Status: Withdrawn
• Enrollment: 0
• Est. completion date: April 13, 2022
• Est. primary completion date: April 13, 2022
• Gender: All
• Age group: 18 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Syndrome
• Visual Snow Syndrome

Intervention

Procedure:
• Neurovisual evaluation
Standardized tests and scales classically used during a neurovisual evaluation,
• 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

Locations

Country	Name	City	State
France	Hôpital Fondation A. de Rothschild	Paris

Sponsors (1)

Lead Sponsor	Collaborator
Fondation Ophtalmologique Adolphe de Rothschild

Country where clinical trial is conducted

France, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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)