Juliana Vanderpluym, M.D., explains how a growing understanding of interictal state symptoms could reshape how patients understand—and treat—their migraine.
Patients with migraine often experience headache-like symptoms during the period between headache episodes, known as the interictal state. Juliana VanderPluym, MD, FAHS, a Pediatric Neurologist at the Mayo Clinic in Phoenix, AZ, has studied these symptoms to examine whether they can be treated to offer patients relief from these symptoms in isolation of their migraine therapy. She recently spoke with the American Headache Society about how interictal state symptoms fit into the larger picture of life with migraine for some patients, and what we know about treatment options.
How do you explain the interictal state?
That’s a difficult question, because our understanding of migraine is constantly changing. New research shows that migraine isn’t just a headache disorder: patients experience their migraine in phases. So when we talk about the interictal phase, we’re really talking about the non-headache phase, compared to the headache phase. In the non-headache phase, there’s the premonitory phase—the period before the headache—and the postdrome phase, which is the period after.
In the premonitory phase, people can experience many different symptoms that they may not recognize are related to their migraine. These can include neuro-psychiatric symptoms like feeling tired, drained or experiencing changes in your emotional state. People might also experience increased sensitivity to light or sound. They can have gastrointestinal symptoms in the form of nausea or intense food cravings. There are a variety of other symptoms patients experience, like stiffness in the neck, increased yawning and even the need to use the washroom more, that can occur during the premonitory phase before a headache attack.
How common is it for patients to experience migraine symptoms on non-headache days?
There have been various studies that have examined this, they found that 80% of patients report having a variety of these symptoms—and that’s just one component of interictal symptoms. Another component is the anxiety people might experience from anticipating their next attack. We know that migraines come and go, and we can’t often predict when an attack will occur. This causes stress for many of people, and that stress affects their day-to-day life. One study found that 10% of people reported experiencing this anxiety, and another 15% of people reported actually cancelling plans to accommodate anticipated migraine pain.
How can understanding of these symptoms help patients manage their migraine?
Understanding interictal state symptoms can help patients forecast their migraine attacks, and also prevent them from misattributing those symptoms to other causes. For example, if they’re feeling a bit irritated, or more tired than usual, they might think they’re coming down with a cold, when in reality those symptoms could be signaling the onset of a migraine attack.
Understanding the function of migraine symptoms outside of the headache phase can also improve patients’ understanding of their triggers. Migraine patients tracking their symptoms will often conclude that eating specific foods seems to induce a headache attack, but interestingly enough, those food cravings may actually be part of the premonitory phase. So the correlation they identify between eating certain foods, and then having a migraine attack soon after, may not mean that food caused the attack, but that their craving for that food is a symptom of their pre-headache phase.
Do patients normally experience all of the symptoms you listed during the interictal state, or just some?
Studies suggest that people can experience a lot of different symptoms. One study reported that patients can experience an average of up to seven different symptoms during the premonitory phase.
Are there ways to treat these symptoms, and would that play a role in preventive migraine treatment?
That’s the million-dollar question we’re still trying to figure out. There have been two studies into potential treatments during the premonitory phase, and both showed some potential benefits. One study looked at a medication called naratriptan, and the other looked at a medication called domperidone. Both studies had patients take the medications when they felt like they were getting a migraine attack based on their premonitory symptoms, and they found that by doing that, people were less like to get a headache later.
Again, these studies were looking at whether the patient got the headache or not. They didn’t look at whether they could treat the interictal symptoms that were being experienced. I think that in the future, we’ll be trying to figure out if we can prevent and treat those symptoms, while also preventing the oncoming migraine.
Juliana VanderPluym M.D., is a member of the American Headache Society, a professional society for doctors and other healthcare workers who specialize in studying and treating headache and migraine. The Society’s objectives are to promote the exchange of information and ideas concerning the causes and treatments of headache and related painful disorders, and to share and advance the work of its members. Learn more about the American Headache Society’s work and find out how you can become a member today.