Visual Snow SyndromeVPVSSNCT06961864
Investigating Brain Function in People With and Without Visual Snow Syndrome Using Adaptation to Visual Stimuli
A study testing Visual Adaptation, Assessments and Questionnaires and Functional Magnetic Resonance Imaging (fMRI) in people with Visual Snow Syndrome and Migraine, run by University of Minnesota at 1 site in United States.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Visual Snow Syndrome, Migraine, Healthy
- What is being tested?
- Visual Adaptation, Assessments and Questionnaires and Functional Magnetic Resonance Imaging (fMRI)
- Type of treatment
- Medical device, Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 100 participants
- Where
- 1 siteUnited States
- Study dates
- 11 Apr 2025to 31 Mar 2030
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
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- 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
Who cannot join
- 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
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- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Hannah Moser, Ph.D. contact
United States1 site, 1 recruiting
- Recruiting
University of Minnesota
Minneapolis, Minnesota, 55455
Michael-Paul Schallmo, Ph.D., Assistant Professor, 612-273-9130, schallmolab@umn.edu
About this study
Official title: Visual Perception in Visual Snow Syndrome
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:
- Undergo assessments and questionnaires to understand visual and mental symptoms, cognitive, and sensory function.
- Make visual judgements based on images presented to them both inside and outside a magnetic resonance imaging (MRI) machine.
- Undergo scanning of their brain while inside of an MRI machine.
- Conditions
- Visual Snow Syndrome, Migraine, Healthy
- Being tested
- Visual Adaptation, Assessments and Questionnaires, Functional Magnetic Resonance Imaging (fMRI), Magnetic Resonance Imaging (MRS)
- Keywords
- Visual Snow Syndrome, Visual Snow, Migraine, Floaters, Palinopsia, Photophobia, Nyctalopia, Entoptic phenomena, Visual trailing, Adaptation, Magnetic resonance spectroscopy, MRS, Magnetic resonance imaging, MRI, University of Minnesota, Afterimages, Poor night vision, Light sensitivity, Persistent positive visual phenomena, Static
- Medical subject headings
- visual snow syndrome, Migraine Disorders, vitreous floaters, palinopsia, Photophobia, Night Blindness, Vitamin A Deficiency
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Visual AdaptationBehavioural
Presentation of visual stimuli to quantify the appearance of visual snow or its effects in the visual system of the brain.
Assessments and QuestionnairesBehavioural
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.
| Study group | Role | What they receive |
|---|---|---|
| People with Visual Snow Syndrome | Active comparator | Not described Receives: Behavioral: Visual Adaptation; Behavioral: Assessments and Questionnaires; Device: Functional Magnetic Resonance Imaging (fMRI); Device: Magnetic Resonance Imaging (MRS) |
| Non-snow Controls | Placebo comparator | Not described Receives: Behavioral: Visual Adaptation; Behavioral: Assessments and Questionnaires; Device: Functional Magnetic Resonance Imaging (fMRI); Device: Magnetic Resonance Imaging (MRS) |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 1.5-2 hours per session, with experiments divided across multiple (e.g., 3) sessions
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.
Measured: 1-2 hours per session, with experiments split across multiple (e.g., 3) sessions
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.
Measured: 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).
Measured: 1-2 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 May 2025
- Study start11 Apr 2025
- Primary completion31 Mar 2030 (estimated)
- Study completion31 Mar 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Visual Snow SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Minnesota
- Sponsor type
- University, hospital or other
- Collaborators
- National Institutes of Health (NIH), Mayo Clinic, National Eye Institute (NEI)
- Responsible party
- Sponsor
- Investigators
- Michael-Paul Schallmo, Ph.D., Principal investigator, University of Minnesota, Department of Psychiatry and Behavioral SciencesStephen A Engel, Ph.D., Study chair, University of Minnesota, Department of PsychologyMichael S Lee, M.D., Study chair, University of Minnesota, Department of Ophthalmology and Visual NeurosciencesAbby Metzler, M.D., Study chair, University of Minnesota, Department of NeurologyMalgorzata Marjanska, Ph.D., Study chair, University of Minnesota, Department of RadiologyCarrie E Robertson, M.D., Study chair, Mayo Clinic, Rochester, Department of Neurology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06961864
- Sponsor's protocol ID
- STUDY00014113
- Other IDs
- R01EY036005
- Acronym
- VPVSS
- Status last verified
- Jan 2026
- First submitted
- 29 Apr 2025
- Last updated
- 14 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: De-identified data will be shared to a public repository at the end of the study. Data that will be shared include the study protocol, informed consent form, analytic code, behavioral data, and brain imaging data. OpenNuero.org will be used for data and Github.com will be used to share code.
Publications
Montoya SA, Mulder CB, Allison KD, Lee MS, Engel SA, Schallmo MP. What does visual snow look like? Quantification by matching a simulation. J Vis. 2024 Jun 3;24(6):3. doi: 10.1167/jov.24.6.3.
PubMed 38837169Montoya SA, Hillstrom AJ, Allison KD, Mulder CB, Moser HR, Lee MS, Schallmo MP, Engel SA. Visual Snow Is Susceptible to the Motion Aftereffect. Invest Ophthalmol Vis Sci. 2025 Oct 1;66(13):23. doi: 10.1167/iovs.66.13.23.
PubMed 41085357Montoya SA, Mulder CB, Lee MS, Schallmo MP, Engel SA. Adapting to Visual Noise Alleviates Visual Snow. Invest Ophthalmol Vis Sci. 2023 Dec 1;64(15):23. doi: 10.1167/iovs.64.15.23.
PubMed 38117246
Study at a glance
From the registry record, last updated by the sponsor on 14 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Visual Perception in Visual Snow Syndrome
- ClinicalTrials.gov ID
- NCT06961864
- Acronym / sponsor ID
- VPVSS / STUDY00014113
- Conditions
- Visual Snow Syndrome, Migraine, Healthy
- Keywords
- Visual Snow Syndrome, Visual Snow, Migraine, Floaters, Palinopsia, Photophobia, Nyctalopia, Entoptic phenomena
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- University of MinnesotaUniversity, hospital or other
- Collaborators
- National Institutes of Health (NIH), Mayo Clinic, National Eye Institute (NEI)
- Study start
- 11 Apr 2025 (actual)
- Primary completion
- 31 Mar 2030 (estimated)
- Study completion
- 31 Mar 2030 (estimated)
- First posted
- 8 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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:
- Undergo assessments and questionnaires to understand visual and mental symptoms, cognitive, and sensory function.
- Make visual judgements based on images presented to them both inside and outside a magnetic resonance imaging (MRI) machine.
- Undergo scanning of their brain while inside of an MRI machine.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| People with Visual Snow Syndrome | Active comparator | Behavioral: Visual Adaptation, Behavioral: Assessments and Questionnaires, Device: Functional Magnetic Resonance Imaging (fMRI), Device: Magnetic Resonance Imaging (MRS) |
| Non-snow Controls | Placebo comparator | Behavioral: Visual Adaptation, Behavioral: Assessments and Questionnaires, Device: Functional Magnetic Resonance Imaging (fMRI), Device: Magnetic Resonance Imaging (MRS) |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (9 listed)
- 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
Key exclusion criteria (37 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Visual AdaptationPresentation of visual stimuli to quantify the appearance of visual snow or its effects in the visual system of the brain. | Behavioural | Non-snow Controls, People with Visual Snow Syndrome |
| Assessments and QuestionnairesAdministration of clinical assessments and questionnaires to gather information about visual and mental symptoms, cognitive, and sensory function. | Behavioural | Non-snow Controls, People with Visual Snow Syndrome |
| Functional Magnetic Resonance Imaging (fMRI)7 tesla fMRI data will be acquired during visual paradigms designed to measure neural responses with and without adaptation. | Device | Non-snow Controls, People with Visual Snow Syndrome |
| Magnetic Resonance Imaging (MRS)7 tesla MRS data will be acquired to quantify the concentrations of different brain chemicals in brain regions including visual cortex. | Device | Non-snow Controls, People with Visual Snow Syndrome |
Primary outcome
Psychophysical Adaptation Task Performance
Time frame: 1.5-2 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) Measures
Time frame: 1-2 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)
Time frame: 1-2 hours
7 telsa MRS data will be acquired to quantify the concentration of different brain chemicals in brain areas including visual cortex.
1 secondary outcome
Clinical Symptom Scores
Time frame: 1-2 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Jan 2026.
- Background: PubMed 38837169Montoya SA, Mulder CB, Allison KD, Lee MS, Engel SA, Schallmo MP. What does visual snow look like? Quantification by matching a simulation. J Vis. 2024 Jun 3;24(6):3. doi: 10.1167/jov.24.6.3.
- Background: PubMed 41085357Montoya SA, Hillstrom AJ, Allison KD, Mulder CB, Moser HR, Lee MS, Schallmo MP, Engel SA. Visual Snow Is Susceptible to the Motion Aftereffect. Invest Ophthalmol Vis Sci. 2025 Oct 1;66(13):23. doi: 10.1167/iovs.66.13.23.
- Background: PubMed 38117246Montoya SA, Mulder CB, Lee MS, Schallmo MP, Engel SA. Adapting to Visual Noise Alleviates Visual Snow. Invest Ophthalmol Vis Sci. 2023 Dec 1;64(15):23. doi: 10.1167/iovs.64.15.23.
- Related InfoLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. De-identified data will be shared to a public repository at the end of the study. Data that will be shared include the study protocol, informed consent form, analytic code, behavioral data, and brain imaging data. OpenNuero.org will be used for data and Github.com will be used to share code.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Hannah Moser, Ph.D. contact
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
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Visual Adaptation, Assessments and Questionnaires and Functional Magnetic Resonance Imaging (fMRI) in people with Visual Snow Syndrome and Migraine, run by University of Minnesota at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 37 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 14 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Michael-Paul Schallmo, Ph.D. ((612) 273-9130, schallmolab@umn.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Psychophysical Adaptation Task Performance (time frame: 1.5-2 hours per session, with experiments divided across multiple (e.g., 3) sessions). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06961864, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Jan 2026.