Episodic Visual Snow Associated with Migraine Attacks

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RESEARCH LETTER Discussion | Three patients report episodes of VS exclusively at the beginning or during migraine attacks. The description was Episodic Visual Snow Associated identical and matched the definition of VS in VSS except for With Migraine Attacks not being continuous.1,2 In the syndrome-defining study,1 only Visual snow syndrome (VSS) is a debilitating disorder charac- patients with continuous VS were included, impeding the iden- terized by continuous visual snow (VS), ie, tiny flickering dots tification of an episodic form. Based on the present case se- in the entire visual field resembling the view of a badly tuned ries, we propose to distinguish between VSS, a debilitating dis- analog television (Figure), plus additional visual symptoms, order characterized by continuous VS and additional visual such as photophobia and palinopsia. There is a high comor- symptoms persisting over years, and eVS, an uncommon self- 1 bidity with migraine and migraine aura. To our knowledge, limiting symptom during migraine attacks. this is the first report of patients with an episodic form of VS The relationship between migraine and VSS is still (eVS), strictly co-occurring with migraine attacks. unresolved.3 Although the severity of VS in VSS does not fluc- tuate in parallel to the migraine cycle,1 the strict co-occurrence Methods | Between January 2016 and December 2017, we saw of eVS and migraine reported here epitomizes a close proxim- 3 patients with eVS and 1934 patients with migraine at our ter- ity.This is in agreement with the clinical picture of migraine being tiary outpatient headache center. Diagnoses were made ac- a disorder of sensory processing4 and VSS being a disorder of vi- cording to the International Headache Society International sual processing1 and also with neuroimaging showing overlap- Classification of Headache Disorders-32 and our previous work,1 ping dysfunctional areas in the visual association cortex.3,5 except for the requirement of permanence for VS. The case se- Episodic VS is uncommon given that only 3 of 1934 patients ries was approved by the Cantonal Ethics Committee Bern (Req- with migraine (<0.2%) were identified despite asking routinely 2017-00698) with waiver of written informed consent based for visual symptoms. It was remarkably linked to migraine attacks on general consent given by all patients. and occurred without the additional symptoms found in VSS.1 In Results | The 3 patients presented initially for headache as chief the first patient, the occurrence prior to headache attacks might complaint. They denied VS outside migraine attacks and did suggest an aura phenomenon. However, the history of migraine not report additional visual symptoms suggestive of VSS dur- without aura in all patients, the brief duration in 1 patient and long ing headache except for photophobia. Neurological examina- duration in 2 patients, the affection of the entire visual field, and tion and magnetic resonance imaging results were normal. the lack of directed movement speak against a cortical spreading 6 Patients experienced black and white (2 patients) or black depressionlike mechanism and thus against eVS being an aura and yellow (1 patient) eVS during migraine attacks, nonfluc- symptom. In clinical practice, a detailed history in patients report- tuating in distribution and severity. Episodes lasted from less ing visual flickering is therefore necessary to differentiate aura than 2 minutes before and during the attack in 1 patient to dur- from eVS. This is important because the diagnosis of aura might ing the entire migraine attack in 2 patients. have implications for patient guidance on contraception or tim- ing of triptan intake.

Figure. Visual Snow Resembling the View of a Badly Tuned Julius Hodak, MD Analog Television Urs Fischer, MD Claudio L. A. Bassetti, MD A Normal vision B Visual snow Christoph J. Schankin, MD

Author Affiliations: Department of Neurology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland. Corresponding Author: Christoph J. Schankin, MD, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse, CH-3010 Bern, Switzerland ([email protected]). Accepted for Publication: September 26, 2019. Published Online: November 25, 2019. doi:10.1001/jamaneurol.2019.4050 Author Contributions: Dr Schankin had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Concept and design: Hodak, Schankin. Acquisition, analysis, or interpretation of data: All authors. Drafting of the manuscript: Hodak, Schankin. Critical revision of the manuscript for important intellectual content: All authors. Statistical analysis: Hodak, Schankin. Obtained funding: Schankin. Administrative, technical, or material support: Hodak. Supervision: Bassetti, Schankin.

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Conflict of Interest Disclosures: Dr Fischer reports grants from the Swiss sociated with increased β-amyloid deposition5 indepen- National Science Foundation, Swiss Heart Foundation, and Medtronic and dently of brain vascular burden, suggesting that gait served as a consultant for Stryker, Medtronic, and CSL Behring outside the submitted work. Dr Schankin reports grants from Swiss Heart Foundation performance may reflect brain pathological burden. 1 outside the submitted work; personal fees from Novartis, Eli Lilly and Company, The findings from Jack et al also confirm that the asso- Almirall, and Allergan outside the submitted work; and personal fees and ciation between AD pathology load and cognitive symptoms nonfinancial support from Teva Pharmaceuticals and Amgen outside the lessens with age. The role of noncognitive symptoms can be submitted work. No other disclosures were reported. even more important in elderly individuals, acting as mark- Funding/Support: This work was supported by Deutsche Migräne-und Kopfschmerzgesellschaft, Eye on Vision Foundation, and Baasch-Medicus ers of impeding decline by reflecting the individual’s brain sus- Foundation. ceptibility to brain pathology load. There is a biological plau- Role of the Funder/Sponsor: The funders had no role in the design and sibility about a shared mechanism because accumulating conduct of the study; collection, management, analysis, and interpretation of knowledge indicates that cognitive and motor symptoms are the data; preparation, review, or approval of the manuscript; and decision to not causally interassociated; instead they reflect a burden in submit the manuscript for publication. 1. Schankin CJ, Maniyar FH, Digre KB, Goadsby PJ. ‘Visual snow’: a disorder brain networks shared by cognitive and motor control. distinct from persistent migraine aura. Brain. 2014;137(pt 5):1419-1428. doi:10. We believe that motor and behavioral symptoms should 1093/brain/awu050 be considered along with cognitive symptoms and pathologi- 2. Headache Classification Committee of the International Headache Society cal biomarkers to achieve improved sensitivity and specific- (IHS). The International Classification of Headache Disorders, 3rd edition. Cephalalgia. 2018;38(1):1-211. ity for classifying risk, identifying phenotypes, and pre- 3. Schankin CJ, Maniyar FH, Sprenger T, Chou DE, Eller M, Goadsby PJ. The dicting disease progression. In this context, asymptomatic relation between migraine, typical migraine aura and “visual snow”. Headache. individuals might be cognitively asymptomatic but have 2014;54(6):957-966. doi:10.1111/head.12378 motor or behavioral changes reflecting underlying pathol- 4. Goadsby PJ, Holland PR, Martins-Oliveira M, Hoffmann J, Schankin C, ogy. This would help to better understand the variability of Akerman S. Pathophysiology of migraine: a disorder of sensory processing. Physiol Rev. 2017;97(2):553-622. doi:10.1152/physrev.00034.2015 the clinical manifestations of neurodegeneration in aging, 5. Boulloche N, Denuelle M, Payoux P, Fabre N, Trotter Y, Géraud G. and importantly, to detect those who may be candidates for Photophobia in migraine: an interictal PET study of cortical hyperexcitability neuroprotective trials aimed at delaying clinical onset of and its modulation by pain. J Neurol Neurosurg Psychiatry. 2010;81(9):978-984. dementia. doi:10.1136/jnnp.2009.190223 6. Hadjikhani N, Sanchez Del Rio M, Wu O, et al. Mechanisms of migraine aura revealed by functional MRI in human visual cortex. Proc Natl Acad SciUSA. Manuel Montero-Odasso, MD, PhD, FRCPC 2001;98(8):4687-4692. doi:10.1073/pnas.071582498 Zahinoor Ismail, MD, FRCPC Richard Camicioli, MD, FRCPC COMMENT & RESPONSE Author Affiliations: Gait and Brain Lab, Parkwood Institute, Lawson Health Research Institute, School of Medicine and Dentistry, Division of Geriatric Alzheimer Disease, Biomarkers, Medicine, Departments of Medicine and Epidemiology and Biostatistics, and Clinical Symptoms—Quo Vadis? University of Western Ontario, London, Ontario, Canada (Montero-Odasso); To the Editor We read with interest the article from Jack et al,1 University of Calgary, Calgary, Alberta, Canada (Ismail); University of Alberta, and its Editorial that shows that the prevalence of 2 neuro- Edmonton, Alberta, Canada (Camicioli). pathologic hallmarks of Alzheimer disease (AD), β-amyloid Corresponding Author: Manuel M. Montero-Odasso, MD, PhD, FRCPC, Gait and Brain Lab, Parkwood Institute, Lawson Health Research Institute, School of plaques, and neurofibrillary tangles is much higher than the Medicine and Dentistry, Division of Geriatric Medicine, Department of Medicine, prevalence of 3 associated clinical manifestations: mild cog- University of Western Ontario, 550 Wellington Rd, Room A2-129, London, ON nitive impairment, dementia, and probable AD.1 Notably, this N6C 0A7, Canada ([email protected]). asymptomatic prevalence of brain load biomarker increased Published Online: February 3, 2020. doi:10.1001/jamaneurol.2019.4959 by 3 times in those 85 years and older.1 Conflict of Interest Disclosures: Dr Montero-Odasso’s program in Gait and We want to address that the manifestation of noncogni- Brain Health is supported by grants from the Canadian Institutes of Health Research (MOP 211220, PJT 153100), the Ontario Ministry of Research and tive symptoms may help to disentangle the complex associa- Innovation (ER11–08–101), the Ontario Neurodegenerative Diseases Research tion between β-amyloid plaques and tau tangles load and im- Initiative (OBI 34739), the Canadian Consortium on Neurodegeneration in peding cognitive decline in AD and associated dementias. Aging (FRN CNA 137794), and the Department of Medicine Program of Specifically, motor symptoms can precede dementia cogni- Experimental Medicine Research Award (POEM 768915), University of Western Ontario. He is the first recipient of the Schulich Clinician-Scientist Award. tive symptoms by a decade,2 and in 30% of cases of AD, neu- Additional Information: The content of this Letter to the Editor reflects the ropsychiatric symptoms can emerge before cognitive symp- discussions and opinions in a recent “Canadian Consensus in Noncognitive toms. A meta-analysis including 9577 participants revealed that Markers in Dementia" panel held during the 10th Canadian Consensus slow gait speed was associated with a 94% increase in short- Conference on Dementia; October 3 to 5, 2019; Quebec City, Quebec, Canada. term risk of incident dementia, suggesting that this motor 1. Jack CR Jr, Therneau TM, Weigand SD, et al. Prevalence of biologically vs clinically defined Alzheimer spectrum entities using the National Institute on symptom may precede cognitive symptoms.3 The dual-task gait Aging–Alzheimer’s Association research framework [published online July 15, test (walking while talking) evaluates cognitive-motor inter- 2019]. JAMA Neurol. 2019. doi:10.1001/jamaneurol.2019.1971 associations by acting as a brain stress test to detect imped- 2. Buracchio T, Dodge HH, Howieson D, Wasserman D, Kaye J. The trajectory of ing cognitive decline. The dual-task gait test seems to be par- gait speed preceding mild cognitive impairment. Arch Neurol. 2010;67(8): 980-986. doi:10.1001/archneurol.2010.159 ticularly valuable in individuals with mild cognitive 3. Kueper JK, Speechley M, Lingum NR, Montero-Odasso M. Motor function impairment, detecting those at higher risk to progress to de- and incident dementia: a systematic review and meta-analysis. Age Ageing. mentias, mainly to AD.4 Gait impairments have been also as- 2017;46(5):729-738. doi:10.1093/ageing/afx084

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