Grant: CIHR Fellowship

Migraine is a common headache disorder. When they occur on at least 15 days/month, patients are classified as having chronic migraine. Determining an appropriate and beneficial treatment for these patients is challenging. While several therapeutic options are available, their efficacy is not sufficient. One noninvasive approach gaining recognition for the treatment of migraine is repetitive transcranial magnetic stimulation (rTMS), which works by stimulating the surface of the scalp, such that the underlying brain tissue is either excited or inhibited. Stimulation can also influence distant brain regions via structural and functional connections. Previous studies examined the effects of rTMS to part of the brain called the dorsolateral prefrontal cortex (DLPFC) with mixed results. One reason for these findings is that crude methods were used to target the DLPFC. To determine if rTMS to the DLPFC is an effective treatment for chronic migraine, precise individualized targeting is required. The purpose of this study is to use a brain imaging method called resting-state functional magnetic resonance imaging (MRI) to target the DLPFC in patients undergoing rTMS for the chronic migraine. 90 patients with chronic migraine will undergo baseline MRI scans and questionnaires to assess their headache pain and disability. These resting-state scans will be used to individually target the DLPFC based on how it is connected to another brain region, the dorsal anterior cingulate cortex (known to be involved in pain perception) for each patient. Follow-up MRI scans will take place five days post-treatment. We hypothesize that rTMS will effectively reduce headache outcome measures in the active rTMS group only, and that the the resting-state connectivity between the DLPFC and anterior cingulate will be increased. Improving the efficacy of rTMS has significant implications for improving patient quality of life and reducing the socio-economic burden associated with this disorder.