The study, to be published in the Nov. 20 issue of the journal Neurology, measured the thickness of the somatosensory cortex(SSC) — the part of the brain responsible for processing information related to touch such as temperature and pain — and found the area to be 21 per cent thicker on average in brains affected by migraines.
Previous research on the SSC has found that it becomes thinner in neurological disorders such as multiple sclerosis and Alzheimer's disease. It thickens with motor training and learning.
The research team measured the thickness of the SSC in 24 migraine patients, half of whom experienced auras — such as flickering lights, loss of vision or numbness — and compared the results with 12 subjects of the same sex and age who did not suffer from migraines.
"Migraineurs had on average thicker SSCs than the control group," the study said, with the most significant changes measured in the area of the SSC that processes information for the head and face.
Additionally, the study said that patients who experienced migraines without auras showed thickening in a larger area of the cortex.
"Repeated migraine attacks may lead to, or be the result of, these structural changes in the brain," study author Dr. Nouchine Hadjkhani said in a release.
"Most of these people have been suffering from migraines since childhood, so the long-term overstimulation of the sensory fields in the cortex could explain these changes. It's also possible that people who develop migraines are naturally more sensitive to stimulation."
The researchers said the findings may also help to explain the high occurrence of other pain disorders in migraine sufferers, such as back pain and fibromyalgia.
Fibromyalgia is a chronic condition characterized by widespread pain in muscles, ligaments and tendons, as well as fatigue and multiple tender points — places on the body where slight pressure causes pain. Fibromyalgia is more common in women than in men.