More than 300 million people around the world suffer from migraines -- intense, throbbing headaches often accompanied by auras, light-sensitivity, nausea and a change in visual or sensory function.
Previous research on migraine patients has shown atrophy of cortical regions of the brain, related to pain processing, perhaps due to chronic stimulation of those areas. The cortical region refers to the cortex, or outer layer of the brain.
In a new study, Italian scientists looked at the cortical thickness and surface area of migraine sufferers, and found that some are likely to have brain abnormalities at birth, and some develop them over the course of time.
The study was led by Dr. Massimo Filippi, director of the Neuroimaging Research Unit at the University Ospedale San Raffaele and professor of neurology at the University Vita-Salute's San Raffaele Scientific Institute in Milan, who wanted to understand the pathophysiological basis of neurological diseases, including migraines, using neuroimaging technology.
Several years ago, he started studying migraine patients with MRIs to define the structural and functional abnormalities associated with migraines in order to identify the mechanisms leading to its clinical expression and offer markers to monitor its evolution. Filippi said it has been known for a long time that migraine patients harbor white matter lesions of possible vascular origin.
"We published extensively on this topic, and in essence, tried to define the nature of white matter lesions seen in patients with migraine, to define the microstructural architecture of normal-appearing tissues and assess the functional cortical changes that are at work to compensate for tissue damage," Filippi told FoxNews.com.
Filippi and his colleagues used MRI sequences to identify focal brain lesions in the white matter and measure brain volume of 81 subjects, 63 with migraines and 18 healthy controls. The study found that migraine sufferers do indeed have a reduced cortical surface area and cortical thickness of regions that are part of the pain-processing network in the human brain.
But, he added, these two types of abnormalities do not fully overlap.
"Interestingly, cortical surface area increases dramatically during late fetal development, and cortical thickness changes dynamically throughout the entire lifespan as a consequence of development and disease," Filippi said. "Based on these findings, we speculate that migraine patients might have a sort of cortical signature -- or abnormal cortical surface area -- which could make them more susceptible to pain and abnormal processing of painful conditions and stimuli. Then, the occurrence of disease might lead to additional cortical abnormalities, or reduced cortical thickness."
To gain additional insight into these issues, Filippi will follow up with patients to find out if cortical abnormalities are stable, or if they tend to become worse over time. He'll also conduct a similar study on pediatric migraine patients. Combined, the two studies should shed light on whether the abnormalities are the cause or result of the pathological condition.
Filippi said the abnormalities found at birth seem to be more extensive in distribution than those that develop later on in life.
Similarly, he found subtle differences of both cortical thickness and cortical surface area between patients with and those without aura, he added.
"The differences were mainly located in regions involved in visual and somatosensory processing, as well as attentional modulation," Filippi said.
It is important to note that Filippi thinks part of these brain abnormalities are actually causing the migraines, while a portion of them is the consequence of repeated migraine attacks over time.
"I would suggest . . .treating migraines might partially correct these abnormalities," Filippi added.