Migraine may be a risk factor for structural changes in the brain, according to a systematic review and meta-analysis published in the October 1 issue of Neurology. White matter abnormalities, infarct-like lesions, and reductions in gray matter and white matter volume appear to be more common among patients with migraine than among healthy controls.
The association with brain changes may be stronger for migraine with aura than for migraine without aura. A meta-analysis of white matter abnormalities indicated an association with migraine with aura, but not with migraine without aura, said Sait Ashina, MD, PhD, Assistant Professor of Neurology, Pain Medicine, and Palliative Care at the Albert Einstein College of Medicine and Beth Israel Medical Center in New York City. A meta-analysis of infarct-like lesions found no difference between migraineurs with aura and controls or between migraineurs without aura and controls. The association with infarct-like lesions was stronger for migraine with aura than for migraine without aura.
Migraine and Abnormalities on MRI
Although neurologists generally have considered migraine a benign disorder without long-term consequences for the brain, recent studies have suggested that migraineurs are at increased risk for various brain changes that can be detected on MRI. Dr. Ashina and colleagues conducted a systematic review and meta-analysis to investigate the possible association between migraine and these brain changes.
The investigators searched PubMed for articles published between 1989 and 2013 that investigated MRI abnormalities in migraineurs. After removing duplicate articles and screening the rest for eligibility, the researchers included 23 studies in the review. Thirteen of these investigations were clinic-based studies, and six were population-based studies. Four additional studies were based on the same cohort. Eligible articles described original studies with a case–control, cross-sectional, and cohort design.
Study data were collected using MRI on a migraine sample and a contemporaneous control group. Most studies used the diagnostic criteria of the International Classification of Headache Disorders.
Gender’s Effect on Migraine
In one population-based study, the prevalence of deep white matter abnormalities was higher among female migraineurs than among female controls. Among men in the same study, deep white matter abnormalities were not influenced by the presence, subtype, or frequency of migraine. A nine-year follow-up study showed that women with migraine, especially without aura, had a higher incidence of deep white matter abnormality progression than controls.
An Icelandic longitudinal study found that patients with migraine with aura at midlife had an increased risk of infarct-like lesions in late life. Female migraineurs with aura had a twofold increased risk of cerebellar infarct-like lesions. Results were not significant for men.
“The clinical and functional significance of these brain lesions is uncertain,” said Dr. Ashina. “Patients with white matter abnormalities can be reassured. Patients with infarct-like lesions should be evaluated for stroke risk factors.
“Additional longitudinal studies with a broad range of disease frequency and severity are needed to fully understand the association between migraine and structural changes in the brain and to clarify the association to attack frequency and disease duration, as well as the influence of these lesions on brain function and prognosis,” Dr. Ashina concluded.
—Erik Greb
Senior Associate Editor