Magnetic flimmers: 'light in the electromagnetic darkness'

Visually stressful striped patterns alter human visual cortical functional connectivity

Visually stressful striped patterns with a spatial frequency (SF) of around 3 cycles per degree (cpd) can induce perceptual illusions/distortions and visual discomfort in most people, headaches in patients with migraine, and seizures in patients with photosensitive epilepsy. Patterns with SF ∼0.3 cpd have no such effects and are not uncomfortable to look at (non-stressful). The effects of the striped patterns on visual cortical activation have been investigated, but their effects on the visual cortical network remain to be studied. A prolonged visual stimulation with stressful patterns may alter the functional connections within the visual system, and their relationship with other networks. Using resting-state fMRI, this study revealed that the functional connections within the visual system were significantly enhanced by visually stressful stimulation. The functional connectivity between V1 and other brain regions was also significantly modified. Non-stressful stimulation produced no such significant effects. More importantly, the effects outlasted the stimulation, and this applied both to those effects within and those beyond the visual cortex, suggesting that repeated prolonged visual stimulation with stressful patterns may alter functional connections of the brain and this might be utilized as a visual neuromodulation approach for treatments of visually triggered headaches in migraine patients and visually induced seizures in patients with photosensitive epilepsy. Hum Brain Mapp 38:5474-5484, 2017. © 2017 Wiley Periodicals, Inc.

Neuromodulation of chronic headaches: position statement from the European Headache Federation

The medical treatment of patients with chronic primary headache syndromes (chronic migraine, chronic tension-type headache, chronic cluster headache, hemicrania continua) is challenging as serious side effects frequently complicate the course of medical treatment and some patients may be even medically intractable. When a definitive lack of responsiveness to conservative treatments is ascertained and medication overuse headache is excluded, neuromodulation options can be considered in selected cases. Here, the various invasive and non-invasive approaches, such as hypothalamic deep brain stimulation, occipital nerve stimulation, stimulation of sphenopalatine ganglion, cervical spinal cord stimulation, vagus nerve stimulation, transcranial direct current stimulation, repetitive transcranial magnetic stimulation, and transcutaneous electrical nerve stimulation are extensively published although proper RCT-based evidence is limited. The European Headache Federation herewith provides a consensus statement on the clinical use of neuromodulation in headache, based on theoretical background, clinical data, and side effect of each method. This international consensus further gives recommendations for future studies on these new approaches. In spite of a growing field of stimulation devices in headaches treatment, further controlled studies to validate, strengthen and disseminate the use of neurostimulation are clearly warranted. Consequently, until these data are available any neurostimulation device should only be used in patients with medically intractable syndromes from tertiary headache centers either as part of a valid study or have shown to be effective in such controlled studies with an acceptable side effect profile.