Visual Snow in Migraine With Aura: Further Characterization by Brain Imaging, Electrophysiology, and Treatment – Case Report

Ünal-Çevik, Isın; Yıldız, F.

doi:10.1111/head.12628

Cited by 61 publications

(73 citation statements)

References 16 publications

(47 reference statements)

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“…Currently the VS pathophysiology and treatment options are under investigation . In our previous case report, we have demonstrated that loss of habituation ability in a VS patient with migraine was improved with lamotrigine treatment . There was a comment whether loss of habituation was due to visual snow or migraine to our case report .…”

Section: Introductionmentioning

confidence: 51%

“…The discrepancy may be because of the different methodology in these studies . In our study, 10 blocks of 100 responses to repetitive pattern stimuli were recorded and averaged . The habituation response was calculated according to the 10th‐1st block response, which is compatible with 1000 VEP responses per eye.…”

Section: Discussionmentioning

confidence: 99%

“…The ground electrode was placed on the neck. Ten blocks of 100 responses to repetitive pattern stimuli were recorded and averaged (sweep duration, 300 milliseconds; bandpass, 1‐100 Hz) as described previously . Briefly, the 1st, 5th, and 10th blocks were analyzed in terms of N75 (N1), P100 (P1) negative and positive deflection peak latencies, and peak‐to‐peak maximal amplitudes.…”

Section: Methodsmentioning

confidence: 99%

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The Clinical Characteristics and Neurophysiological Assessments of the Occipital Cortex in Visual Snow Syndrome With or Without Migraine

2019

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Objective Visual snow syndrome (VS) is mainly characterized by flickering, little dots in both visual fields. The recognition of the clinical entity of VS has been increasing recently. Diagnosis is based on patient reports and not better accounted for by another diagnosis. Background The exact pathophysiology of this syndrome is still unknown. In this study, our aim was to investigate the role of neurophysiological assessments of the occipital cortex in VS patients with (VSm) or without migraine (VSwom) and the healthy control (HC). Methods To assess the occipital cortex hyperexcitability, we conducted a prospective, observational study to investigate the habituation/potentiation response by repetitive pattern reversal visual evoked potentials (rVEP) and examined the phosphene thresholds (PT) by transcranial magnetic stimulation in VS patients with or without migraine who were admitted to our tertiary headache clinic and the healthy control. Results Twenty‐nine volunteers were recruited. The VSm (n = 10), the VSwom (n = 7), and the HC group (n = 12) did not differ demographically. Flickering and floaters were reported in all VS patients and flickering in the dark was the most distressing symptomatology in both VS groups. Higher VAS scores for palinopsia (trailing), photophobia, and concentration difficulty were more frequently self‐reported by VSm patients. The HC demonstrated habituation; however, there was loss of habituation response and decreased PTs in both groups of VS patients. The N1P1 VEP amplitude ratios of the 10th/1st block from right and left eye stimulation disclosed higher values (lack of habituation) in VSm (1.04 ± 0.2 and 1.06 ± 0.2) and the VSwom (1.05 ± 0.2 and 0.96 ± 0.08) patients compared to the healthy control (0.75 ± 0.1 and 0.79 ± 0.1), P = .002 from right eye and P = .003 from left eye. In the post hoc analysis the VS patients did not differ according to the presence of migraine from right or left eye stimulations (both P > .999). The left occipital cortex PTs were lower in VSm (58.00 ± 6.60) and VSwom (62.14 ± 11.53) and higher in the HC (71.33 ± 5.56) P = .009. In the post hoc analysis the VS patients did not differ according to the presence of migraine (P > .999). The right occipital cortex PTs were lower in VSm (60.30 ± 8.15) and VSwom (62.00 ± 10.95), higher in the HC (69.67 ± 8.04); however, statistically, groups did not differ (P = .087). Conclusions The loss of habituation and lower threshold for occipital cortex excitability were demonstrated electrophysiologically in VS patients. While statistically significant loss of habituation was seen in both VS patients (with or without migraine) in the right eye, statistically significant loss of habituation in the left eye and decreased threshold of left occipital cortex excitability was seen in visual snow with migraine patients. These findings may provide new insights on “visual snow” pathophysiology and serve as an objective and quantitative assessment tool in VS patients.

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Section: Introductionmentioning

confidence: 51%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The Clinical Characteristics and Neurophysiological Assessments of the Occipital Cortex in Visual Snow Syndrome With or Without Migraine

2019

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“…In contrast, VEPs to repeated stimulation are often potentiated, or increased, in patients with migraine . Consistent with this idea, a recent study reported VEP potentiation associated with visual snow . However, these results have been questioned due to the patient's prior history of migraine with aura, as well as more general concerns about the reliability of VEP habituation in migraine …”

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confidence: 89%

Antagonistic Relationship Between VEP Potentiation and Gamma Power in Visual Snow Syndrome

2017

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Objective.-Using a "double-pulse" adaptation paradigm, in which two stimuli are presented in quick succession, this study examines the neural mechanisms underlying potentiation of the visual evoked potential (VEP) in visual snow syndrome.Background.-Visual snow is a persistent visual disturbance characterized by rapid flickering dots throughout the visual field. Like the related condition of migraine with aura, visual snow has been hypothesized to arise from abnormal neuronal responsiveness, as demonstrated by a lack of typical VEP habituation to repeated visual stimulation. Yet the exact neural mechanisms underlying this effect remain unclear. Previous "double-pulse" experiments suggest that typical VEP habituation reflects disruptive gamma-band (50-70 Hz) neural oscillations, possibly driven by inhibitory interneurons. Given that migraine has been associated with reduced cortical inhibition, we propose here that visual snow may likewise reflect diminished inhibitory activity, resulting in decreased gamma power following initial visual stimulation and concomitant potentiation of the subsequent VEP response.Methods.-We compared VEP responses to double-pulse adaptation in a 22-year-old man with a 2-year history of visual snow versus a group of age-and gender-matched controls (N 5 5). The patient does not have a comorbid diagnosis of episodic migraine or migraine with aura, and controls had no personal or family history of migraine.Results.-In contrast to the pattern of habituation observed in controls, visual snow was associated with persistent potentiation of the VEP response. Consistent with our predictions, time-frequency analysis revealed reduced gamma-band power following the initial stimulus in visual snow relative to controls.Conclusions.-These results support an antagonistic interplay between gamma power and rapid neural adaptation, shedding new light on the neural mechanisms of VEP potentiation in visual snow.

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“…Therefore, we believe that the potentiation effect on rVEPs that the authors described cannot be unequivocally attributed to VS but rather seems to be related to the underlying MWA. We suggest that this finding should be more prudently confirmed on a larger number of patients, possibly trying to make a distinction between the subgroups of VS with or without comorbid migraine.…”

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confidence: 78%

Can We Speak of Lack of Habituation in Visual Snow?

2016

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Visual Snow in Migraine With Aura: Further Characterization by Brain Imaging, Electrophysiology, and Treatment – Case Report

Abstract: The visual snow and loss of habituation ability in migraine associated with occipital bending can be improved with lamotrigine treatment. This report may provide new insights on "visual snow" pathophysiology in migraine.

Cited by 61 publications

References 16 publications

The Clinical Characteristics and Neurophysiological Assessments of the Occipital Cortex in Visual Snow Syndrome With or Without Migraine

The Clinical Characteristics and Neurophysiological Assessments of the Occipital Cortex in Visual Snow Syndrome With or Without Migraine

Antagonistic Relationship Between VEP Potentiation and Gamma Power in Visual Snow Syndrome

Can We Speak of Lack of Habituation in Visual Snow?

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