Health TrialsbyHealthPanel

Investigating Brain Function in People With and Without Visual Snow Syndrome Using Adaptation to Visual Stimuli

ConditionsVisual Snow SyndromeMigraineHealthy
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-60
SponsorUniversity of Minnesota

About this trial

The goal of this study is to learn more about the brain pathways and activity involved in creating Visual Snow Syndrome (VSS). The main questions it aims to answer are:

* Does VSS arise from spontaneous activity in brain pathways? * Where in the brain does the activity contributing to VSS arise? * How does brain activity contribute to VSS?

Participants will:

1. Undergo assessments and questionnaires to understand visual and mental symptoms, cognitive, and sensory function. 2. Make visual judgements based on images presented to them both inside and outside a magnetic resonance imaging (MRI) machine. 3. Undergo scanning of their brain while inside of an MRI machine.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

Between the ages of 18 and 60 years old

Normal (20/25 or better in each eye) or corrected-to-normal vision (MR-compatible glasses will be provided as needed)

Ability to comply with study instructions

Individuals who have a current diagnosis of VSS from a neuro-ophthalmologist or meet diagnostic criteria of VSS (experience of dynamic dots across the visual field persisting longer than 3 months and at least 2 of the following additional visual symptoms: palinopsia, entoptic phenomena, trails behind moving objects, photophobia, or nyctalopia)

Disqualifiers

Not being fluent in English or another language for which interpretation/translation services are available

A diagnosed or self-reported intellectual disability

Current substance dependence (besides nicotine), or drug dependence with tolerance or withdrawal within past 12 months

Hallucinogenic substance use within the past 12 months or hallucinogenic substance use within 12 months prior to onset of VSS symptoms

Trial design

Design model

Parallel

Treatments tested in this trial

  • Visual Adaptation

    Behavioral

    Presentation of visual stimuli to quantify the appearance of visual snow or its effects in the visual system of the brain.

  • Assessments and Questionnaires

    Behavioral

    Administration of clinical assessments and questionnaires to gather information about visual and mental symptoms, cognitive, and sensory function.

  • Functional Magnetic Resonance Imaging (fMRI)

    Device

    7 tesla fMRI data will be acquired during visual paradigms designed to measure neural responses with and without adaptation.

  • Magnetic Resonance Imaging (MRS)

    Device

    7 tesla MRS data will be acquired to quantify the concentrations of different brain chemicals in brain regions including visual cortex.

Treatment groups

100 Participants
are divided into 2 treatment groups
Group A: People with Visual Snow SyndromeActive comparator 4 interventions
Group B: Non-snow ControlsPlacebo comparator 4 interventions

Trial outcomes

Primary outcomes

1

Psychophysical Adaptation Task Performance

Visual tasks will consist of perceptual judgments following adaptation (e.g., subject will report when internal or external / simulated visual snow appears the same on the left or right side of the screen). Measures will be compared for visual target stimuli in different task conditions and experiments, with the goal of understanding the neural basis of visual snow.

Time frame
1.5-2 hours per session, with experiments divided across multiple (e.g., 3) sessions
2

Functional Magnetic Resonance Imaging (fMRI) Measures

7 tesla fMRI data will be acquired during visual paradigms designed to measure neural responses with and without adaptation. FMRI data will be processed and analyzed to quantify the effect of adaptation across different regions in visual cortex.

Time frame
1-2 hours per session, with experiments split across multiple (e.g., 3) sessions
3

Magnetic Resonance Spectroscopy (MRS)

7 telsa MRS data will be acquired to quantify the concentration of different brain chemicals in brain areas including visual cortex.

Time frame
1-2 hours

Secondary outcomes

1

Clinical Symptom Scores

Measures of visual and mental symptoms, cognitive, and sensory function (e.g., Visual Snow Questionnaire), will be collected using self-report and interview methods. Scores will be compared across groups to differences in visual and mental symptoms in people with and without visual snow syndrome (VSS).

Time frame
1-2 hours

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

University of Minnesota

Lead sponsor

National Institutes of Health (NIH)

Collaborator

Mayo Clinic

Collaborator

National Eye Institute (NEI)

Collaborator

Source ClinicalTrials.gov
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