Assessment of characteristic disease signs and evaluation of a treatment approach with low-intensity electrical brain stimulation in persons with visual snow syndrome

Diagnostic markers and neuromodulatory treatment approach with transcranial alternating current stimulation (tACS) for visual snow syndrome

Status

Recruiting

Phases

Phase 2

Study type

Interventional

Source

ISRCTN

Registry ID

ISRCTN55942704

Enrollment

Registered

2023-01-19

Start date

2023-04-13

Completion date

Unknown

Last updated

2023-05-22

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Neuromodulatory treatment approach and evaluation of diagnostic marker for the Visual Snow Syndrome (a migraine related perceptual disorder). Nervous System Diseases

Interventions

Current intervention as of 13/04/2023: Part 1: ”Diagnostic markers of the Visual Snow Syndrome” 1. EEG: For each subject (20 controls and 20 patients), we will perform a high-density EEG (64 Channels)

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: Current inclusion criteria as of 13/04/2023: Subjects with VSS: 1. Informed consent signed 2. Subjects with VSS should fulfill the criteria of the International Headache Society (ICDH 3, A1.4.6) Controls: 1. Informed consent signed 2. Matched to the subjects with VSS (sex, age and migraine) _____ Previous inclusion criteria: 1. Informed consent signed 2. Subjects with VSS should fulfil the criteria of the International Headache Society (ICDH 3, A1.4.6)

Exclusion criteria

Exclusion criteria: Current exclusion criteria as of 13/04/2023: Subjects with VSS: 1. Contraindications and limitations of the MD as described in the instructions for use: implanted electrical devices, cranial implants (like metal plates or screws), skull defects or head injuries 2. Contraindications to the class of MD under investigation, e.g. known hypersensitivity or allergy to the device material (rubber or sponge materials) 3. Pregnancy 4. Skin diseases with lesions on the scalp 5. Persons who are less than 18 years old All subjects: 6. Clinically significant concomitant disease states (like epilepsy, brain tumors, traumatic, infectious or metabolic lesions or diseases of the brain, sleep disorders) 7. Known or suspected non-compliance 8. Inability to follow the procedures of the investigation, e.g. due to language problems, psychological disorders, dementia, etc., of the subject 9. Participation in another investigation with an investigational drug or another medical device within the 30 days preceding and during the present investigation 10. Enrolment of the PI, their family members, employees and other dependent persons 11. Auditory and visual (if not correctable with glasses) impairment 12. Pharmaceutical treatment for conditions related to the central nervous system 13. Therapeutic treatment which change the excitability of the central nervous system 14. Illicit substances or other substances that modify a person’s natural perception regardless of whether those are commonly understood as therapeutic drugs _____ Previous exclusion criteria: 1. Implanted electrical devices, cranial implants (like metal plates) or screws, skull defects or head injuries 2. Allergy to the device material 3. Clinically significant concomitant disease states (e.g., bipolar disorder, schizophrenia, epilepsy and structural cerebral lesions and other conditions when the investigator thinks it may not be safe to include a specific patient) 4. Vulnerable subjects 5. Known or suspected non-compliance, drug or alcohol abuse, 6. Inability to follow the procedures of the investigation 7. Skin diseases with lesions on the scalp 8. Auditory or visual impairment

Design outcomes

Primary

Measure	Time frame
Current primary outcome measures as of 10/05/2023: Part 1: ”Diagnostic markers of the Visual Snow Syndrome”: In this part of the study, we will perform group comparisons between subjects with Visual Snow Syndrome and matched controls. 1. EEG: 1.1. Differences between subjects affected by VSS and controls in individual alpha-rhythm (8-13Hz) concerning power and frequency at rest and during visual stimulation over occipital electrodes (O1, O2, Oz) measured on visit 1 2. Visual tasks: 2.1. Performance in the visual tasks (discrimination blocks, detection blocks, and object recognition blocks) as measured by reaction times if the answers are correct, measured on visit 1 Part 2: “Neuromodulatory treatment approach”: 1. Differences in VSS-density (VSS Scale, Puledda et al) after verum and sham stimulation (compared to the score before the beginning of the stimulation block) 2. Differences in the noisy object recognition task between verum and sham stimulation session (compared to the score before the beginning of the stimulation block) _____ Previous primary outcome measures as of 13/04/2023: Part 1: ”Diagnostic markers of the Visual Snow Syndrome”: In this part of the study, we will perform group comparisons between subjects with Visual Snow Syndrome and matched controls. 1. EEG: 1.1. Differences between subjects affected by VSS and controls in individual alpha-rhythm (8-13Hz) concerning power and frequency at rest and during visual stimulation over occipital electrodes (O1, O2, Oz) 2. Visual tasks: 2.1. Performance in the visual tasks (discrimination blocks, detection blocks, and object recognition blocks) as measured by reaction times if the answers are correct Part 2: “Neuromodulatory treatment approach”: 1. Differences in VSS-density (VSS Scale, Puledda et al) after verum and sham stimulation (compared to the score before the beginning of the stimulation block) 2. Differences in the noisy object recognition task between verum and sham stimulation session (compar	—

Measure

Time frame

Current primary outcome measures as of 10/05/2023: Part 1: ”Diagnostic markers of the Visual Snow Syndrome”: In this part of the study, we will perform group comparisons between subjects with Visual Snow Syndrome and matched controls. 1. EEG: 1.1. Differences between subjects affected by VSS and controls in individual alpha-rhythm (8-13Hz) concerning power and frequency at rest and during visual stimulation over occipital electrodes (O1, O2, Oz) measured on visit 1 2. Visual tasks: 2.1. Performance in the visual tasks (discrimination blocks, detection blocks, and object recognition blocks) as measured by reaction times if the answers are correct, measured on visit 1 Part 2: “Neuromodulatory treatment approach”: 1. Differences in VSS-density (VSS Scale, Puledda et al) after verum and sham stimulation (compared to the score before the beginning of the stimulation block) 2. Differences in the noisy object recognition task between verum and sham stimulation session (compared to the score before the beginning of the stimulation block) _____ Previous primary outcome measures as of 13/04/2023: Part 1: ”Diagnostic markers of the Visual Snow Syndrome”: In this part of the study, we will perform group comparisons between subjects with Visual Snow Syndrome and matched controls. 1. EEG: 1.1. Differences between subjects affected by VSS and controls in individual alpha-rhythm (8-13Hz) concerning power and frequency at rest and during visual stimulation over occipital electrodes (O1, O2, Oz) 2. Visual tasks: 2.1. Performance in the visual tasks (discrimination blocks, detection blocks, and object recognition blocks) as measured by reaction times if the answers are correct Part 2: “Neuromodulatory treatment approach”: 1. Differences in VSS-density (VSS Scale, Puledda et al) after verum and sham stimulation (compared to the score before the beginning of the stimulation block) 2. Differences in the noisy object recognition task between verum and sham stimulation session (compar

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Secondary

Measure	Time frame
Current secondary outcome measures as of 10/05/2023: Part 1: ”Diagnostic markers of the Visual Snow Syndrome”: 1. EEG: 1.1. Differences in the mean alpha peak frequency over the occipital electrodes (visit 1) 1.2. Differences of amplitude between subjects affected by VSS and controls in the mean Oddball mismatch-potential (at 100–350 ms) (visit 1) 1.3. Differences in the Chirp-response (between 18 and 26Hz) between subjects affected by VSS and controls (visit 1) 2. Visual tasks: 2.1. Autonomic reaction as measured by change in pupil size and heart rate when presented with the oddball (unexpected visual stimulus) compared between subjects with VSS and controls (visit 1) 3. Sensory discomfort thresholds: 3.1. Difference in mean sensory thresholds between subjects affected by VSS and controls (visit 1) Part 2: “Neuromodulatory treatment approach”: 1. Quality of life assessed using the SF-36 scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 2. Anxiety assessed using the GAD-7 scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 3. Insomnia severity assessed using the ISI scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 4. Fatigue impact assessed using the FSS scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 5. Sleepiness assessed using the Epworth Sleepiness Scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 6. Depression scores assessed using PHQ-8 after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 7. Differences in occipital alpha rhythm power between baseline (day 1) and after the last stimulation session (day 5) _____ Previous secondary outcome measures as of 13/04/2023: Part 1: ”Diagnostic markers of the Visual Snow Syndrome”: 1. EEG: 1.1. Differences in the alpha frequency over the occipital electrodes 1.2. Differences of amplitude between subjects affected by VSS	—

Measure

Time frame

Current secondary outcome measures as of 10/05/2023: Part 1: ”Diagnostic markers of the Visual Snow Syndrome”: 1. EEG: 1.1. Differences in the mean alpha peak frequency over the occipital electrodes (visit 1) 1.2. Differences of amplitude between subjects affected by VSS and controls in the mean Oddball mismatch-potential (at 100–350 ms) (visit 1) 1.3. Differences in the Chirp-response (between 18 and 26Hz) between subjects affected by VSS and controls (visit 1) 2. Visual tasks: 2.1. Autonomic reaction as measured by change in pupil size and heart rate when presented with the oddball (unexpected visual stimulus) compared between subjects with VSS and controls (visit 1) 3. Sensory discomfort thresholds: 3.1. Difference in mean sensory thresholds between subjects affected by VSS and controls (visit 1) Part 2: “Neuromodulatory treatment approach”: 1. Quality of life assessed using the SF-36 scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 2. Anxiety assessed using the GAD-7 scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 3. Insomnia severity assessed using the ISI scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 4. Fatigue impact assessed using the FSS scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 5. Sleepiness assessed using the Epworth Sleepiness Scale after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 6. Depression scores assessed using PHQ-8 after the last stimulation (day 5), after 1 week (day 12) and 1 month (day 33) 7. Differences in occipital alpha rhythm power between baseline (day 1) and after the last stimulation session (day 5) _____ Previous secondary outcome measures as of 13/04/2023: Part 1: ”Diagnostic markers of the Visual Snow Syndrome”: 1. EEG: 1.1. Differences in the alpha frequency over the occipital electrodes 1.2. Differences of amplitude between subjects affected by VSS

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Countries

Germany, Switzerland

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 4, 2026