Modulating cortical responsiveness by tACS in visual snow syndrome - a case report

Background: Studies have shown that migraineurs have an enhanced photic-drive response when exposed to a visual chirp compared to healthy controls. Visual Snow Syndrome (VSS) is associated with migraines, but patients have continuous visual symptoms indicating dysfunction in visual processing. For this reason, we want to determine whether VSS patients show a similar reaction as migraineurs when exposed to visual chirp stimulation. Additionally, we want to see whether t-ACS stimulation lowers their reaction significantly. Method: One VSS patient (female, 37) with comorbid migraines was exposed to visual chirp stimulation (5.55 – 60 Hz) in a dimly lit room in front of a PC monitor (50 cm). There were 66 flashes per trial, totaling 792 flashes. A 64-electrode EEG grid was used for the measurement, with the occipital electrodes used for analysis. Power spectral density was calculated for stimulus responses and corrected for baseline. A wavelet transformation was applied before averaging the data. The patient received a total of 9 t-ACS stimulations over a period of 5 days between measurements. Results: The VSS patient showed a high occipital response to visual chirp stimulation pre-t-ACS stimulation and a lower occipital response to visual chirp stimulation post-t-ACS stimulation across all frequencies. Conclusion: This study shows that visual chirps could serve as a potential biomarker for VSS and that t-ACS stimulation over an extended period of time might be able to lower the photic-drive response, which could represent a novel treatment approach for VSS

Migraine Aura-Catch Me If You Can with EEG and MRI-A Narrative Review.

Roughly one-third of migraine patients suffer from migraine with aura, characterized by transient focal neurological symptoms or signs such as visual disturbance, sensory abnormalities, speech problems, or paresis in association with the headache attack. Migraine with aura is associated with an increased risk for stroke, epilepsy, and with anxiety disorder. Diagnosis of migraine with aura sometimes requires exclusion of secondary causes if neurological deficits present for the first time or are atypical. It was the aim of this review to summarize EEG an MRI findings during migraine aura in the context of pathophysiological concepts. This is a narrative review based on a systematic literature search. During visual auras, EEG showed no consistent abnormalities related to aura, although transient focal slowing in occipital regions has been observed in quantitative studies. In contrast, in familial hemiplegic migraine (FHM) and migraine with brain stem aura, significant EEG abnormalities have been described consistently, including slowing over the affected hemisphere or bilaterally or suppression of EEG activity. Epileptiform potentials in FHM are most likely attributable to associated epilepsy. The initial perfusion change during migraine aura is probably a short lasting hyperperfusion. Subsequently, perfusion MRI has consistently demonstrated cerebral hypoperfusion usually not restricted to one vascular territory, sometimes associated with vasoconstriction of peripheral arteries, particularly in pediatric patients, and rebound hyperperfusion in later phases. An emerging potential MRI signature of migraine aura is the appearance of dilated veins in susceptibility-weighted imaging, which may point towards the cortical regions related to aura symptoms ("index vein"). Conclusions: Cortical spreading depression (CSD) cannot be directly visualized but there are probable consequences thereof that can be captured Non-invasive detection of CSD is probably very challenging in migraine. Future perspectives will be elaborated based on the studies summarized

Associations between stress and migraine and tension-type headache: Results from a school-based study in adolescents from grammar schools in Germany

Introduction: Stress is considered the major contributor to migraine and tension-type headache in adolescents. Previous studies have focused on general stressors, whereas the aim of the present study was to investigate associations between individuals’ stressful experiences and different types of headache. Methods: Adolescents from 10th and 11th grades of grammar schools filled in questionnaires. Stressful experiences were measured with the Trier Inventory of Chronic Stress. Type of headache was classified according to the International Classification of Headache Disorders. Linear regressions, adjusted for sex and grade, were calculated to estimate differences in stress scores that can be attributed to migraine, tension-type headache or miscellaneous headache. Results: A total of 1260 questionnaires were analysed. Tension-type headache, migraine and co-existing migraine plus tension-type headache were found in 48.7%, 10.2% and 19.8% of the participants. In subjects with migraine or co-existing migraine plus tension-type headache, high increases in stress scores were found in all investigated dimensions, whereas much weaker and inconsistent associations were found in subjects with tension-type headache only. Conclusions: The characteristic of migraine is more associated with stressful experiences than this is the case for tensiontype headache. This suggests that adolescent migraine patients might specially benefit from behavioural interventions regarding stress

Visual snow syndrome after start of citalopram-novel insights into underlying pathophysiology

Purpose!#!Chronic pain is common in the older population and a significant public health concern. However, comprehensive studies on analgesics use in this age group from Germany are scarce. This study aims to give a comprehensive overview on the use of the most common therapeutic groups of analgesics in community-dwelling older adults from Germany.!##!Methods!#!A cross-sectional study was carried out using data from a German cohort of 2038 community-dwelling adults aged 63-89 years. Descriptive statistics and logistic regression models were applied to assess the utilization of analgesics by age, sex, pain severity, pain duration, and locations.!##!Results!#!One out of four study participants was suffering from high-intensity or disabling pain. Approximately half of those taking analgesics still reported to suffer from high-intensity or disabling pain. Among analgesics users, occasional non-steroidal anti-inflammatory drugs (NSAIDs) use was the most frequent pain therapy (in 43.6% of users), followed by metamizole (dipyrone) use (16.1%), regular NSAIDs use (12.9%), strong opioids use (12.7%), and weak opioids use (12.0%). In multivariate logistic regression models, higher age, higher pain severity, longer pain duration, abdominal pain, and back pain were statistically significantly associated with opioids use. Metamizole use was also statistically significantly associated with higher pain severity but inversely associated with pain duration.!##!Conclusions!#!A significant number of older German adults are affected by high-intensity and disabling chronic pain despite receiving analgesics. Long-term studies are needed to compare the effectiveness and safety of different treatments for chronic pain in older adults

Corrigendum: Editorial: Visual Snow: Old Problem, New Understanding.

[This corrects the article DOI: 10.3389/fneur.2022.884752.]

Self-reported muscle pain in adolescents with migraine and tension-type headache

Aim: To identify possible associations between muscular pain and headache in adolescents in a large population-based sample. Methods: Grammar school students were invited to fill in a questionnaire on headache and associated lifestyle factors. Headache was classified according to the German version of the International Classification of Headache Disorders (2nd edition). Muscular pain was assessed via denoting affected areas in schematic drawings of a body and via provoked muscular pain on controlled movements of head, neck and shoulder regions. Results: Prevalence of any headache within the previous 6 months exceeded 80%. In all subjects muscular pain or pain on movement was most prominent in the neck and shoulder region, ranging from 9% to 27% in the non-headache population to up to 63% for individuals with migraine or mixed migraine and tension-type headache (TTH). Frequency of muscular pain increased significantly with growing chronicity of TTH. Interpretation: A strong association between muscle pain in the neck/shoulder region and headache was observed, pointing to the importance of muscular pain for headache in adolescents. Also, in this age group muscular pain appears to be of particular importance in chronic TTH and – unexpectedly – in migraine, which is the most important new finding in our study

Natural course of visual snow syndrome: a long-term follow-up study.

Visual snow syndrome is characterized by a continuous visual disturbance resembling a badly tuned analogue television and additional visual and non-visual symptoms causing significant disability. The natural course of visual snow syndrome has not hitherto been studied. In this prospective longitudinal study, 78 patients with the diagnosis of visual snow syndrome made in 2011 were re-contacted in 2019 to assess symptom evolution using a semi-structured questionnaire. Forty patients (51% of 78) were interviewed after 84 ± 5 months (mean ± SD). In all patients, symptoms had persisted. Visual snow itself was less frequently rated as the most disturbing symptom (72 versus 42%, P = 0.007), whereas a higher proportion of patients suffered primarily from entopic phenomena (2 versus 17%, P = 0.024). New treatment was commenced in 14 (35%) patients, of whom in seven, visual snow syndrome was ameliorated somewhat. Three (7%) experienced new visual migraine aura without headache, and one (2%) had new migraine headache. There were no differences in the levels of anxiety and depression measured by the Patient Health Questionnaire 8 and the Generalized Anxiety Disorder Scale 7. Thirty-eight patients (49%) were lost to follow-up. In visual snow syndrome, symptoms can persist over 8 years without spontaneous resolution, although visual snow itself might become less bothersome

Disrupted connectivity within visual, attentional and salience networks in the visual snow syndrome.

Here we investigate brain functional connectivity in patients with visual snow syndrome (VSS). Our main objective was to understand more about the underlying pathophysiology of this neurological syndrome. Twenty-four patients with VSS and an equal number of gender and age-matched healthy volunteers attended MRI sessions in which whole-brain maps of functional connectivity were acquired under two conditions: at rest while watching a blank screen and during a visual paradigm consisting of a visual-snow like stimulus. Eight unilateral seed regions were selected a priori based on previous observations and hypotheses; four seeds were placed in key anatomical areas of the visual pathways and the remaining were derived from a pre-existing functional analysis. The between-group analysis showed that patients with VSS had hyper and hypoconnectivity between key visual areas and the rest of the brain, both in the resting state and during a visual stimulation, compared with controls. We found altered connectivity internally within the visual network; between the thalamus/basal ganglia and the lingual gyrus; between the visual motion network and both the default mode and attentional networks. Further, patients with VSS presented decreased connectivity during external sensory input within the salience network, and between V5 and precuneus. Our results suggest that VSS is characterised by a widespread disturbance in the functional connectivity of several brain systems. This dysfunction involves the pre-cortical and cortical visual pathways, the visual motion network, the attentional networks and finally the salience network; further, it represents evidence of ongoing alterations both at rest and during visual stimulus processing

Age- and frequency-dependent changes in dynamic contrast perception in visual snow syndrome

OBJECTIVE Patients with visual snow syndrome (VSS) suffer from a debilitating continuous (\textquotedblTV noise-like\textquotedbl) visual disturbance. They report problems with vision at night and palinopsia despite normal visual acuity. The underlying pathophysiology of VSS is largely unknown. Currently, it is a clinical diagnosis based on the patient's history, an objective test is not available. Here, we tested the hypothesis that patients with VSS have an increased threshold for detecting visual contrasts at particular temporal frequencies by measuring dynamic contrast detection-thresholds. METHODS Twenty patients with VSS were compared to age-, gender-, migraine- and aura-matched controls in this case-control study. Subjects were shown bars randomly tilted to the left or right, flickering at six different frequencies (15 Hz, 20 Hz, 25 Hz, 30 Hz, 35 Hz, 40 Hz). The contrast threshold (CT) for detection of left or right tilt was measured in a two-alternative adaptive forced-choice procedure (QUEST). The threshold was defined as the Michelson contrast necessary to achieve the correct response in 75% of the cases. RESULTS The CT increased for higher flicker frequencies (ANOVA: main effect frequency: F (5,180) = 942; p < 0.001), with an additional significant frequency*diagnosis interaction (ANOVA: F (5,180) = 5.00; p < 0.001). This interaction effect was due to an increased CT at a flicker frequency of 15 Hz in the VSS cohort (VSS: MC = 1.17%; controls: MC = 0.77%). At the other frequencies, group comparisons revealed no differences. Furthermore, in the VSS cohort we observed an increase of CT with higher age (r = 0.69; p < 0.001), which was not seen in controls (r = 0.30; p = 0.20). CONCLUSIONS This study demonstrates a lower visual contrast sensitivity exclusively at 15 Hz in VSS patients and demonstrates frequency-dependent differences in dynamic contrast vision. The peak sensitivities of both parvo- and magnocellular visual pathways are close to a frequency of about 10 Hz. Therefore, this frequency seems to be of crucial importance in everyday life. Thus, it seems plausible that the impairment of contrast sensitivity at 15 Hz might be an important pathophysiological correlate of VSS. Furthermore, the overall age-related decrease in contrast sensitivity only in VSS patients underscores the vulnerability of dynamic contrast detection in VSS patients. Dynamic CT detection seems to be a promising neurophysiological test that may contribute to the diagnosis of VSS