Migraine with visual aura associated with thicker visual cortex

Abstract

Until recent years it was believed that migraine with aura was a disorder causing intermittent neurological symptoms, with no impact on brain structure. However, recent MRI studies have reported increased cortical thickness of visual and somatosensory areas in patients with migraine with aura, suggesting that such structural alterations were either due to increased neuronal density in the areas involved, or a result of multiple episodes of cortical spreading depression as part of aura attacks. Subsequent studies have yielded conflicting results, possibly due to methodological reasons, e.g. small number of subjects. In this cross-sectional study, we recruited females aged 30-60 years from the nationwide Danish Twin Registry. Brain MRI of females with migraine with aura (patients), their co-twins, and unrelated migraine-free twins (controls) were performed at a single centre and assessed for cortical thickness in predefined cortical areas (V1, V2, V3A, MT, somatosensory cortex), blinded to headache diagnoses. The difference in cortical thickness between patients and controls adjusted for age, and other potential confounders was assessed. Comparisons of twin pairs discordant for migraine with aura were also performed. Comparisons were based on 166 patients, 30 co-twins, and 137 controls. Compared with controls, patients had a thicker cortex in areas V2 [adjusted mean difference 0.032 mm (95% confidence interval 0.003 to 0.061), V3A [adjusted mean difference 0.037 mm (95% confidence interval 0.008 to 0.067)], while differences in the remaining areas examined were not statistically significant [adjusted mean difference (95% confidence interval): V1 0.022 (-0.007 to 0.052); MT: 0.018 (-0.011 to 0.047); somatosensory cortex: 0.020 (-0.009 to 0.049)]. We found no association between the regions of interest and active migraine, or number of lifetime aura attacks. Migraine with aura discordant twin pairs (n = 30) only differed in mean thickness of V2 (0.039 mm, 95% CI 0.005 to 0.074). In conclusion, females with migraine with aura have a thicker cortex corresponding to visual areas and our results indicate this may be an inherent trait rather than a result of repeated aura attacks.

Interictal Hyperperfusion in the Higher Visual Cortex in Patients With Episodic Migraine

“…In contrast, a study with MwA found cortical thickness increases which were most pronounced in V5 and V3A. 34 In addition, a recent study revealed increased cortical thickness in V2 and V3A in females with MwA compared to controls, and increased cortical thickness of V2 in twins with MwA compared to their discordant twin pairs, 53 indicating that structural changes in visual cortex may be an inherent trait. Whether this is true for functional brain alterations needs to be addressed in future studies.…”

“…34 In addition, a recent study revealed increased cortical thickness in V2 and V3A in females with MwA compared to controls, and increased cortical thickness of V2 in twins with MwA compared to their discordant twin pairs, 53 indicating that structural changes in visual cortex may be an inherent trait. We did not find increased cortical thickness or volume in the clusters with increased CBF, except of a larger volume in the right STG (P < .001, uncorrected).…”

Recent Insights in Migraine With Aura: A Narrative Review of Advanced Neuroimaging

“…Compared with HC, patients with MwA (eg, both concordant and discordant twin pairs) showed a thicker V2 and V3A cortex, while MwA discordant twin pairs (eg, patients with a co‐twin without MwA) only differed in V2 thickness. Taken together, the authors suggested that slightly thicker cortical visual areas observed in patients with MwA are more likely to represent a trait correlating with this type of migraine rather than a result of aura attacks …”

“…Increased thickness of V2 and V3A areas was confirmed in a large cohort of female patients with exclusively MwA . More specifically, Hougaard and colleagues conducted a cross‐sectional study, recruiting from the nationwide Danish Twin Registry, 166 female patients with MwA, 30 co‐twins controls without MwA, and 137 HC . The authors performed an “individual‐based analysis” between twin subjects without migraine and twin patients experiencing MwA (only a little percentage was suffering also from MwoA).…”

“…The authors performed an “individual‐based analysis” between twin subjects without migraine and twin patients experiencing MwA (only a little percentage was suffering also from MwoA). Moreover, also a “within‐pairs analysis” was conducted between 30 patients with MwA (8/30 suffering also from MwoA) vs 30 co‐twin sisters with no history of MwA (10/30 suffering also from MwoA) . Compared with HC, patients with MwA (eg, both concordant and discordant twin pairs) showed a thicker V2 and V3A cortex, while MwA discordant twin pairs (eg, patients with a co‐twin without MwA) only differed in V2 thickness.…”