Modern thermodynamics provides concepts that elucidate certain aspects of migraines. While medical physics is traditionally related to diagnostic instruments, with these theoretical concepts, a new avenue opens up how physics enters clinical research.

I openly confess that I wrote the title to catch your attention, yet I believe that this phrase stands on solid scientific grounds. You may agree and think yes, physics and headaches are inseparably linked. This would be a different story. For me headaches are not caused by physics and, moreover, I think there is little if any physics of headaches.

Confused? Read on.

Before I raise your expectations too high, let me clarify that this blog post is about outlining a coherent picture where physics enters migraine research. No attempt is made to actually explain these physical concepts in detail. It is like if I would write, hey, there is a physics of skateboarding for you really need to know about concepts of gravity and momentum to appreciate the amazing skating tricks. When I am at the point writing what the gravity and momentum of migraines would be, that is, what the names of the corresponding physical concepts are, this post will end.

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Headache is a symptom, migraine is a disease

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How can I write about the physics of migraines and at the same time ensuring that there is no physics of headaches? The answer lies in a German saying "Migraines are headaches, even if you don't have any". The aphorism became famous after Erich Kästner used it in his children book "Anna Louise and Anton". Unfortunately, it is quoted more often to stigmatize migraine sufferers rather than to characterize one clinical type of migraine that lacks headaches. But Kästner knew what he was talking about, he suffered from migraines himself.

In fact, the official migraine classification knows six types of migraines and even more subforms. The point is, headache is a symptom, migraine is a disease, and, furthermore though less obvious (hence the post), also physical concepts are needed to understand this disease in its complete entirety, which, of course, we are far away from.



What symptoms other than headaches occur in a migraine attack?

People with migraines can, for example, experience visual or tactile hallucinations. The full range of possible neurological symptoms is extremely large. The symptoms are summarized under the name migraine aura. A nearly complete listing of aura symptoms is found on the website of the Migraine Aura Foundation, a non-profit organization founded by Klaus Podoll, a neurologist, and myself. Literally hundreds of descriptions of neurological symptoms have been collected and categorized. This is an enormous amount of work done by Klaus Podoll—and it is still ongoing—to help people to recognize and understand their symptoms during migraine.

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The link between physics and migraine

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So when I write about physical concepts that are needed in addition to physiological concepts to understand migraine, I mean the physical concepts behind migraine with aura. Today it is widely accepted that migraine aura is caused by a phenomenon called spreading depression (SD).

SD, the process underlying migraine aura, is a self-organized pattern formation process: Highly complex neural interactions essentially lead to a traveling wave pattern of pathological activity in the brain propagating with about 3mm/min over the cortical surface. This is five orders of magnitude slower than usually communication in the brain is transmitted.

Image from Wikipedia (GNU Free Documentation License)

Wave propagation is a domain of physics, no doubt about that. If you now have difficulties imagining a wave in your brain, think about a stadium crowd performing "the wave" (Mexican wave, or Audience wave). Replace the overly excited sport fans with neurons and the picture you get is quite close.

Modern thermodynamics provides physical concepts to study wave propagation in what we call excitable media (let it be sport fans in a stadium or neurons in the brain). Excitability and threshold, just to name such concepts, can be precisely defined on mathematical grounds. We can study the equations of migraine using computer models and make prediction how to interfere with the brain to prevent attacks. 

Modern thermodynamics provides physical concepts for many other systems, like the physics of traffic jams and so on. So migraine is just one particular example where spatio-temporal patterns evolve. It is an example many people might not have thought of as a research field for phycists.