White matter functional networks have shown alterations with the presence of aura in migraine, suggesting that aura vs no-aura disease subtypes may need to be treated as separate entities in the future, according to a study recently published in Frontiers in Neurology.
Of the 51 participants included in this study, 18 had migraine with aura and 33 of whom had migraine without aura, as well as 32 age- and sex-matched healthy controls. Functional magnetic resonance imaging (MRI) results were collected on the participants at resting state, as well as 60 directional diffusion tensor images and T1-weighted images at high resolution. White matter was extracted from the images, and white matter functional networks were identified using independent component analysis.
Comparison of resting state white matter functional networks between disease subtypes was performed with dual regression, with component spatial maps used as spatial regressors against data from the functional MRI scans. Groups were compared in terms of resting functional MRI variations through the use of Fourier transforms to decompose network activity. The study researchers calculated voxel-wise correlation for intergroup diffusion parameters and differences in white matter functional activity.
Among 8 white matter networks identified, 3 expressed differently between migraine with aura and migraine without aura. Comparatively higher expression was observed in migraine with aura among all 3 networks. Both BOLD amplitude fluctuation and functional connectivity were higher in the aura group. Among the aura group, functional MRI fluctuation correlated positively with fractional anisotropy (r=0.61; P <.05) and negatively with perpendicular diffusivity (r=-0.55; P <.05).
Limitations of this study include relatively small sample sizes, unequal group sizes, and a lack of accounting for multiple comparisons.
The study researchers conclude that “white matter functional networks similar to the gray matter resting state functional networks show alterations in migraine with aura,” revealing a relationship with the associated microstructure. Another novel finding was that “alterations of resting state functional fluctuation showed a strong association with parameters of the underlying white matter microstructure.”
Faragó P, Tóth E, Kocsis K, et al. Altered resting state functional activity and microstructure of the white matter in migraine with aura [published online October 1, 2019]. Front Neurol. doi: 10.3389/fneur.2019.01039