Intracranial Recording Reveals New Insight into Migraine Aura
A recent case study published in Headache: The Journal of Head and Face Pain, Mapping the Intracranial Recording of Cortical Spreading Depression and Migraine with Aura, by Dr. Graham McLeod and colleagues, presents a unique look into cortical spreading depression (CSD) by capturing it in real-time from within the brain of a patient experiencing an attack of migraine with aura.
As Dr. McLeod noted in the interview, “While admitted to us on the epilepsy monitoring unit with the electrodes implant, she had a migraine with aura… we looked at the EEG at the time and we saw changes that were quite striking. The brainwave activity got very flat and suppressed for hours starting during that migraine.”
Watch the full discussion with Dr. McLeod:
Headache publishes original articles covering all aspects of head and face pain, including basic and clinical research. This study adds rare, direct evidence of CSD in humans, contributing to a growing body of evidence that deepens our understanding of migraine with aura and its potential mechanisms.
In this case, a 32-year-old woman admitted for epilepsy monitoring had intracranial electrodes placed as part of a pre-surgical evaluation. During her stay, she experienced a migraine with aura, allowing the team to observe the flattening of brainwave activity on one side of the brain, providing a rare, direct recording of cortical spreading depression (or depolarization, as it’s also known). While CSD has been hypothesized and modeled since the 1940s, and observed indirectly through imaging, this case is the first known example of CSD captured via direct intracranial EEG.
This finding offers strong validation of CSD, a widely accepted but previously unproven mechanism behind migraine aura. It also underscored how vital thorough patient history and multi-disciplinary collaboration can be in complex cases. As Dr. McLeod explained, “Taking the time to just go through a history really thoroughly and carefully with the patient made all the difference both for her epilepsy and for this migraine.”
This study may inform future diagnostic approaches or inspire new lines of research exploring migraine mechanisms more deeply. It also raises new questions for the headache medicine community such as, how can these recordings shape our understanding of aura? Could this lead to more targeted therapies? And how might future studies build on this evidence?
As tools and technology evolve, researchers will gain deeper insights into the neurological underpinnings of migraine, particularly through rare cases like this that offer a glimpse into the condition at the cortical level.
This case study provides the first direct, intracranial recording of CSD in a human during a migraine with aura — affirming long-standing theories and highlighting the value of close clinical observation and interdisciplinary care.
Read the Interview Transcript:
Dr. Rashmi Halker Singh
I'm Dr. Rashmi Halker Singh. I'm the deputy editor of Headache. And it's my pleasure today to be joined by Dr. Graham McLeod, who's the first author of a recent publication entitled Mapping the Intracranial Recording of Cortical Spreading Depression and Migraine with Aura. So, so welcome. I'm so happy to be speaking with you about this recent case study that you submitted to headache.
Dr. Graham A. McLeod
Thank you, Dr. Halker, thank you for having me. Likewise. And I'm happy to be here as well.
Dr. Rashmi Halker Singh
So this is a really interesting case that you all submitted and I was wondering if you could just share the experience. What was, tell us about the story, what was the patient, what was the experience? What did you all do?
Dr. Graham A. McLeod
Sounds good. So I encountered this case while I was on my epilepsy rotation in Calgary with Drs. Wiebe and Dr. Josephson, other authors on this paper. And we kind of stumbled across this case by happenstance. There was this patient, a 32-year-old female, admitted to the epilepsy monitoring unit. She had epilepsy or has epilepsy and undergoing pre-surgical evaluation with intracranial electrodes. So, you know, electrodes inside the brain recording the activity directly from the brain itself and the cortex. And she also had a history of migraines, migraines with and without aura. And while admitted to us on the epilepsy monitoring unit with the electrodes implanted, she had a migraine with aura. She had, you know, we could talk more about the aura. It was a visual aura in one of the quadrants specifically and on her EEG. You know, we looked at the EEG at that time and we saw changes that were quite striking. The brainwave activity got very flat and suppressed for hours starting during that migraine. So we thought that was interesting. We thought we might submit it as a case report. And then as we were looking through the literature, we realized this type of thing actually hasn't been seen or reported before to our knowledge. So ended up putting it together for a case report, but ended up kind of right place, right time, interesting finding. And then on further investigation, it turned out to be something that was relatively new. Although it's been measured in kind of other indirect ways from other modalities. It's never been shown in this way on the direct recording of the brainwaves from inside the skull. So. So that was, that was very interesting.
Dr. Rashmi Halker Singh
Absolutely. I mean, it must have been a fascinating experience. We talk a lot about aura in so many different situations with patients from preclinical recordings, you know the history of migraine, all of that. To really capture it in a patient in such a happenstance way, especially someone who's admitted for a completely different indication as well. It must have been an exciting experience. I mean, it really led me to. My second question was for you to kind of share why this was such a significant finding. I think you answered that and wanted to know if you had anything else to share about that as well.
Dr. Graham A. McLeod
Yeah, thank you for asking. Well, you know, at the time, step one was making sure this patient was okay. Actually, as we're recording the brainwaves and then suddenly they're, they're quite flat in one hemisphere, which you don't usually see. And us, that. That's kind of concerning. So obviously, you know, we checked on the patient and she was doing well. She didn't have a headache yet. She had this quadrantinopia. We sent her for a CT scan, and the CT scan was all clear. So that was kind of step one. Like, what is, what is this, what is this actually telling us, you know, these, these flat brain waves? And it was only kind of, as the day went on, and in retrospect, and going a bit more through her history of migraine with her, that we realized what, what this was. And, and, sorry, your question. Could you repeat your question?
Dr. Rashmi Halker Singh
I was just asking if you had anything else to share about why this was such a significant finding. But I think you really touched upon that, given this was really the first time we were able to record migraine aura in this manner.
Dr. Graham A. McLeod
I think so. From my reading, this is something that's been hypothesized or conjectured in some way since the 1940s. And certainly going through med school, they teach or they taught me that migraine probably is linked with cortical spreading depression. But it's one of those things where as you follow the citations and you look like, no, it hasn't really been recorded in this way. It's been kind of indicated in other ways with, you know, PET scans and FMRI scans. But, but this was, this was a unique way of recording it or showing it or maybe another, another piece of evidence that it, that it's part of the, part of the problem in migraine.
Dr. Rashmi Halker Singh
Absolutely. So I think we learn so much from our patients. I think they're the best teachers. And I think sharing case reports and case studies is one great way to share that with others. And I'm curious to know what you learned from this patient. Anything else that you want to tell us? That you haven't already shared in this paper.
Dr. Graham A. McLeod
What I would take away is I think this case underscores the value of patient history. The value, like the informational value about how much it could tell you about what is actually happening from a diagnostic standpoint. So this patient has epilepsy and has seizures and also has migraine and it's really only by the event semiology and the characteristics that we're able to tell one from the other. And even reaching her diagnosis of epilepsy, her spells were a bit atypical and it took a couple of consultations to reach the conclusion that they were actually epileptic and to start on treatment and proceed with the pre-surgical evaluation. So taking the time to just go through a history really thoroughly and carefully with the patient made all the difference both for her epilepsy and for this migraine, for her migraines and including the one that we captured with the brainwaves. So I think it is a good example of just the value of history. And she herself had of course, a lot of strong, resilient, admirable personality characteristics with this marathon of a 33-day admission. So I don't want to say too much with confidentiality, but those would be some lessons from the case.
Dr. Rashmi Halker Singh
Absolutely. I think listening to the patient, allowing them to tell their story and validating them are really important lessons that we can always learn. So, Dr. McLeod, you shared with me that you are a fourth-year resident, you've already matched for your epilepsy fellowship at Stanford. So congratulations on that. We are so excited for you and look forward to many great things in your future and I'm excited to follow your career as well. So thank you for all of that.
Dr. Graham A. McLeod
Thank you, Dr. Halker, it was great to speak with you this morning and thank you for the kind words.
Dr. Rashmi Halker Singh
Absolutely.