Women Who Get Migraines with Visual Auras Have Thicker Visual Cortexes
MRI study finds that patients who suffer from migraines with auras have a thicker cortex in visual areas of the brain when compared to controls
Migraine with aura, a headache disorder that couples intense pain with a sensory disturbance, affects about 8 percent of the general population. Visual auras are by far the most common type of sensory disturbance and often manifest as flashes of light, blind spots, or hallucinations. However, it isn't known why such strange episodes occur in migraine patients.
A team of Danish researchers wanted to find out whether an altered brain structure could play a role in the phenomenon. They performed structural MRI in both migraine patients and controls, looking for differences in the cortical thickness of visual and somatosensory areas. Compared with controls, patients who suffered from migraine with aura had a thicker cortex corresponding to visual -- but not somatosensory -- areas of the brain.
The authors recruited women aged 30 to 60 from the nationwide Danish Twin Registry and divided them into three groups: 172 patients who had been diagnosed as having migraine with aura, 34 of their twins, and 139 non-affected controls. Participants underwent whole-brain MRI imaging, and cortical thickness was measured at each point across the cortex at predefined areas of interest.
Patients who suffered from migraine with aura had thicker gray matter than controls in both the secondary and third visual cortices. In pairs of twins in which one twin experienced migraines and the other did not, the migraine-sufferers had thicker visual cortices their unaffected twins, despite having the same DNA. However, somatosensory cortical thickness did not differ between the two groups, and the thickness of cortical regions didn't seem to be related to how often or how recently patients had experienced migraines.
The results, published by the journal Brain in January, suggest that the thicker cortical visual areas represent an inherent trait associated with this type of migraine. The researchers don't believe they reflect damage from the migraines themselves, since patients who suffered from somatosensory aura did not have a thicker cortex in those areas of the brain.