Migraine pathophysiology

Relating Photophobia, Visual Aura, and Visual Triggers of Headache and Migraine

OBJECTIVE

This study investigated a potential association between visual factors and symptoms related to migraine. It was predicted that photophobia and visual aura would be positively associated with interictal light sensitivity and visual headache triggers (flicker, glare, and eyestrain), and that these 2 visual symptoms would also be associated.

BACKGROUND

Previous studies have found independent neurophysiological associations between several visual factors and symptoms related to headache disorders. Many of these connections appear to be associated with increased cortical hypersensitivity, a phenomenon that might be in part due to repeated avoidance and reduced tolerance to triggers. If true, and if associations between visual factors and symptoms can be established, this may have implications for an exposure-based treatment for migraine symptoms.

METHODS

Four hundred and ninety-one participants (411 female, 80 male) were recruited through Griffith University (AUS), Headache Australia, Pain Australia, and through social media. Participants were grouped based on the presence of headache disorder symptoms and the presence or absence of photophobia and/or visual aura. A cross-sectional online survey design was utilized to gather information pertaining to interictal light sensitivity, visual triggers, and visual symptoms.

RESULTS

With respect to interictal light sensitivity and photophobia, a significant difference (P < .001, eta squared [η² ] = 0.084) was found between the 3 groups, where headache disorder participants with photophobia (group A1; mean [M] = 2.5, standard deviation [SD] = 0.97) reported significantly greater light sensitivity than participants with headache disorder and no photophobia (A2; M = 1.68, SD = 0.62) and control group participants (A3; M = 1.82, SD = 0.85). This pattern was repeated for participants reporting flicker as a headache trigger (P < .001, η² = 0.061), with group A1 (M = 2.45, SD = 1.24) significantly higher than groups A2 (M = 1.68, SD = 0.83) and A3 (M = 1.68, SD = 0.89), and was also seen for glare as a headache trigger (P < .001, η² = 0.092), with group A1 (M = 2.92, SD = 0.96) significantly higher than A2 (M = 2.31, SD = 0.89) and A3 (M = 2.09, SD = 0.93). This pattern of results was not replicated for headache disorder participants with and without visual aura. A significant association (P < .001) was found between photophobia and visual aura in headache disorder participants based on a chi-square test of independence, with 86/136 participants reporting either both or neither visual symptom.

CONCLUSIONS

This study supports a link between certain visual phenomena in headache disorder populations, and supports future research into exposure-based treatments for migraine symptoms.

Overview of migraine treatment

SUMMARY Migraine is ranked as the 19th top cause of disability worldwide by WHO. Despite advancements in migraine-specific acute treatment, only a minority of patients utilize these medications. Specific pharmacologic treatments consist of the ergot alkaloids and triptans (serotonin 5-HT1B/1D receptor agonists). Both classes are regarded as relatively safe and effective; however, there is a greater concern for vasoconstrictive effects with the ergots, which limits their use. Triptans transformed migraine therapy, setting in motion revolutionary research that heightened our understanding of migraine mechanisms. However, one in three migraineurs may be triptan nonresponders and there is a group of migraine patients that remains ‘refractory’ to conventional pharmacologic migraine therapy. This article discusses the approach to migraine management, reviews currently available acute and preventive pharmacologic and nonpharmacologic treatment options for migraine headache, as well as briefly focuses on novel and upcoming medicines presently under investigation.