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Investigating Brain Function in Visual Snow Syndrome

This study aims to understand how Visual Snow Syndrome (VSS) affects brain activity and pathways. Researchers will use visual adaptation (showing you visual patterns) and assessments to learn more about your visual and mental symptoms. You will also undergo functional Magnetic Resonance Imaging (fMRI) and Magnetic Resonance Spectroscopy (MRS) scans, which are types of MRI that look at brain activity and chemicals, to see how your brain responds to visual stimuli. The goal is to discover if VSS comes from spontaneous brain activity, where in the brain this activity occurs, and how it contributes to your symptoms. We are looking for 100 participants, aged 18-60, with or without VSS, who have normal or corrected-to-normal vision.

Study design
This is an interventional study planning to enroll 100 participants. It is not specified if it is randomized or blinded.
What's involved
You will complete questionnaires and assessments, make visual judgments based on images, and undergo brain scans inside an MRI machine. These activities will be split across multiple sessions, with each session lasting 1-2 hours.
Compensation
Not stated in the trial record.
Follow-up
Not specified.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06961864

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

Recruiting
NAAges 18–60InterventionalBasic science
University of Minnesota
~100 participants
Updated 2026-01-14 on ClinicalTrials.gov
What's tested:Visual AdaptationAssessments and QuestionnairesFunctional Magnetic Resonance Imaging (fMRI)Magnetic Resonance Imaging (MRS)

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Psychophysical Adaptation Task Performance
Measured over 1.5-2 hours per session, with experiments divided across multiple (e.g., 3) sessions
+2 more outcomes measured

Conditions

Visual Snow Syndrome
Migraine
Healthy

Explore related trials

HealthyMigraineVisual snow syndrome

Where it's being run

1 sites across 1 states
Minnesota1

Study leadership

  • Michael-Paul Schallmo, Ph.D. · PRINCIPAL_INVESTIGATOR · University of Minnesota, Department of Psychiatry and Behavioral Sciences
  • Stephen A Engel, Ph.D. · STUDY_CHAIR · University of Minnesota, Department of Psychology
  • Michael S Lee, M.D. · STUDY_CHAIR · University of Minnesota, Department of Ophthalmology and Visual Neurosciences
  • Abby Metzler, M.D. · STUDY_CHAIR · University of Minnesota, Department of Neurology
  • Malgorzata Marjanska, Ph.D. · STUDY_CHAIR · University of Minnesota, Department of Radiology
  • Carrie E Robertson, M.D. · STUDY_CHAIR · Mayo Clinic, Rochester, Department of Neurology

Who to contact

Michael-Paul Schallmo, Ph.D.
[email protected]
(612) 273-9130
Email the study team

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Eligibility criteria

Inclusion

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)
Individuals living in Minnesota within 2 hours of the study site
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 living in Minnesota within 2 hours of the study site

Exclusion

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
Severe central nervous system disease
Head injury with skull fracture or loss of consciousness for more than thirty minutes
Presence of a physical problem that would render study measures difficult or impossible to administer or interpret (e.g., visual field loss)
Age less than 18 years or greater than 60 years
MRI exclusions (for MR visits only):
Metal in the body that cannot be approved by the CMRR safety committee
Pregnancy
Conditions that affect neuro-hemodynamic coupling
Claustrophobia
Inability to lie still for at least an hour
Weight in excess of 440 lbs
CT scan exclusion only: Research-related radiation exposure within the last 12 months
Any vision anomaly aside from VS or refractive error (e.g., strabismus/ crossed eyes, lazy eyes, color blindness)
Current psychotic episode
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
Severe central nervous system disease
Head injury with skull fracture or loss of consciousness for more than thirty minutes
Presence of a physical problem that would render study measures difficult or impossible to administer or interpret (e.g., visual field loss)
Age less than 18 years or greater than 60 years
MRI exclusions (for MR visits only):
Metal in the body that cannot be approved by the CMRR safety committee
Pregnancy
Conditions that affect neuro-hemodynamic coupling
Claustrophobia
Inability to lie still for at least an hour
Weight in excess of 440 lbs
CT scan exclusion only: Research-related radiation exposure within the last 12 months
Any vision anomaly or refractive error (e.g. strabismus/ crossed eyes, lazy eyes, color blind)
A personal history of VSS symptoms or a diagnosis with VSS
Current psychotic episode

What this trial measures

  • Psychophysical Adaptation Task Performance1.5-2 hours per session, with experiments divided across multiple (e.g., 3) sessions

    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.

  • Functional Magnetic Resonance Imaging (fMRI) Measures1-2 hours per session, with experiments split across multiple (e.g., 3) sessions

    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.

  • Magnetic Resonance Spectroscopy (MRS)1-2 hours

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