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| ID | Type | Description | Link |
|---|---|---|---|
| R01EY036005 | U.S. NIH Grant/Contract | View source |
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| Name | Class |
|---|---|
| National Institutes of Health (NIH) | NIH |
| Mayo Clinic | OTHER |
| National Eye Institute (NEI) | NIH |
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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:
Participants will:
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| People with Visual Snow Syndrome | Active Comparator |
| |
| Non-snow Controls | Placebo Comparator |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Visual Adaptation | Behavioral | Presentation of visual stimuli to quantify the appearance of visual snow or its effects in the visual system of the brain. |
|
| Measure | Description | Time Frame |
|---|---|---|
| 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. | 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. | 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. | 1-2 hours |
| Measure | Description | Time Frame |
|---|---|---|
| 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). | 1-2 hours |
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Inclusion Criteria for People with Visual Snow Syndrome:
Inclusion Criteria for Non-snow Controls:
Exclusion Criteria for People with Visual Snow Syndrome:
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):
Any vision anomaly aside from VS or refractive error (e.g., strabismus/ crossed eyes, lazy eyes, color blindness)
Current psychotic episode
Exclusion Criteria for Non-snow Controls:
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):
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
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Michael-Paul Schallmo, Ph.D. | Contact | (612) 273-9130 | schallmolab@umn.edu | |
| Hannah Moser, Ph.D. | Contact | schallmolab@umn.edu |
| Name | Affiliation | Role |
|---|---|---|
| Michael-Paul Schallmo, Ph.D. | University of Minnesota, Department of Psychiatry and Behavioral Sciences | Principal Investigator |
| Stephen A Engel, Ph.D. | University of Minnesota, Department of Psychology | Study Chair |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University of Minnesota | Recruiting | Minneapolis | Minnesota | 55455 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 38837169 | Background | 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. | |
| 41085357 | Background | Montoya 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. |
| Label | URL |
|---|---|
| Related Info | View source |
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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.
Data will be shared within 12 months of the completion of our study or publication of a relevant manuscript, whichever comes first.
Everyone will be able to access the data shared to the repositories.
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| 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. |
|
| Michael S Lee, M.D. | University of Minnesota, Department of Ophthalmology and Visual Neurosciences | Study Chair |
| Abby Metzler, M.D. | University of Minnesota, Department of Neurology | Study Chair |
| Malgorzata Marjanska, Ph.D. | University of Minnesota, Department of Radiology | Study Chair |
| Carrie E Robertson, M.D. | Mayo Clinic, Rochester, Department of Neurology | Study Chair |
| 38117246 | Background | Montoya 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. |
| ID | Term |
|---|---|
| C000726567 | visual snow syndrome |
| D008881 | Migraine Disorders |
| C000726608 | vitreous floaters |
| C000726587 | palinopsia |
| D020795 | Photophobia |
| D009755 | Night Blindness |
| D014802 | Vitamin A Deficiency |
| ID | Term |
|---|---|
| D051270 | Headache Disorders, Primary |
| D020773 | Headache Disorders |
| D001927 | Brain Diseases |
| D002493 | Central Nervous System Diseases |
| D009422 | Nervous System Diseases |
| D014786 | Vision Disorders |
| D012678 | Sensation Disorders |
| D009461 | Neurologic Manifestations |
| D005128 | Eye Diseases |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D001361 | Avitaminosis |
| D003677 | Deficiency Diseases |
| D044342 | Malnutrition |
| D009748 | Nutrition Disorders |
| D009750 | Nutritional and Metabolic Diseases |
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| ID | Term |
|---|---|
| D011795 | Surveys and Questionnaires |
| D008279 | Magnetic Resonance Imaging |
| ID | Term |
|---|---|
| D003625 | Data Collection |
| D004812 | Epidemiologic Methods |
| D008919 | Investigative Techniques |
| D017531 | Health Care Evaluation Mechanisms |
| D011787 | Quality of Health Care |
| D017530 | Health Care Quality, Access, and Evaluation |
| D011634 | Public Health |
| D004778 | Environment and Public Health |
| D014054 | Tomography |
| D003952 | Diagnostic Imaging |
| D019937 | Diagnostic Techniques and Procedures |
| D003933 | Diagnosis |
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