Hi all,
I’ve been reading some great stuff from Carolyn Bernstein’s book, “The Migraine Brain” and thought we needed some information on mvertigo about exactly what migraine is based on the current science-based evidence.
We tend to hear all sorts of alternative ideas out there (usually without any basis and always without evidence) about how we should treat this based on what practitioners think migraine is. Reading through a chiropractor’s site last night made me think this info is even more necessary because migraine is not something we have done to ourselves because we have led a life that is “too stressed out”, or that we have let ourselves become “too toxic”, or that this is some sort of mechanical problem in the neck. The “toxic” and “detox” argument is particularly vacuous because it’s been used for decades to explain just about any human disease state, makes no logical sense, and is utterly baseless (zero evidence). Yes, cervicogenic vertigo exists in the medical literature but it is extremely rare and usually shows up after whiplash injuries. Furthermore, there are no nerves running through the neck that directly impact the vestibular system (according to Steve Novella, neurologist). We’ve also had lengthy discussion on mvertigo about a gut-migraine connection months back. The jury is still out for me on the latter but if there is a connection it would be more about killing off a potential trigger derived from the gut (some evidence about an effect on the immune system exists) in the same way a bad tooth might be constantly irritating the trigeminal nerve in the face. But the gut does not cause migraine and the associated vertigo we know all too well.
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EDIT: it appears even “cervical vertigo” may not exist based on this new report (Rev Med Suisse. 2009 Sep 30;5(219):1922-4):
Cervical vertigo: myth or reality?
Patients displaying vertigo associated with cervical symptoms: what is the origin? Diagnosis of cervical vertigo is sometimes retained. It remains very controversial. Indeed there is neither a convincing pathological mechanism nor a diagnostic test.
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[size=130]So what is migraine? And where does it come from?[/size]
First, the biggest myth out there is that migraine is some type of headache which we all know is just plain wrong. It is in fact a complex neurological disease that affects the central nervous system. Headache is one symptom but migraine almost never consists of head pain alone and in some, there is no head pain at all. Put simply, migraine is caused by abnormal brain chemistry. It is not something you caused or the result of some emotional problem in your life, or some unconscious effort to be sick to avoid life’s problems. Migraine is a real genetic disorder, in most cases inherited from one or both parents. It is a chronic illness, meaning you cannot get rid of it or wish it away, BUT there is much that can be done to manage it and eliminate triggers (lifestyle changes and/or medication) to the point of it no longer interrupting your life.
The things that trigger an attack in a migraineur vary greatly from one person to the next and can be almost anything. Triggers don’t just merely upset your brain but send it careening out of control with a biochemical chain reaction that results in anything from severe head pain to vomiting, dizziness or even temporary paralysis. The brain is a very complex organ that hates change. While other organs of the body are quite flexible and can handle an increase in output or lots of abuse we throw at them, the brain is not so forgiving. Even in a person without a migraine brain, a night without a good sleep or even too much booze probably means feeling lousy the next day or even developing a mild headache. By contrast, a migraine brain is super high maintenance and hypersensitive – like a diva or a thoroughbred race horse. It wants everything to stay the same and wants to be treated like royalty … throw anything new at it or upset the balance and it can/will react angrily and we pay the price. About 10% of North Americans, British, and Australians have such a brain – that’s about 30 million people (75% women) in the US alone, more than diabetes and asthma combined! Worse only about 50% know they have it.
A myth that still exists out there is that migraine is the result of just a vascular problem – that it is caused by vasodilation or the expanding of blood vessels on pain sensitive structures in the brain. We now know that migraine is a neurological disease that involves much more than the blood vessels (blood vessels expand as a result of the attack). Migraine involves aspects of the central nervous system, neurotransmitters and other brain chemicals, electrical impulses, the body’s inflammatory response, the trigeminal nerve (located in the face and head), and others. The physical reaction that begins the migraine attack is called “cortical spreading depression (CSD)”. CSD is a dramatic wave of electrical excitation that spreads across the surface of the brain (the cerebral cortex) and is set off by a migraine trigger. Because the cerebral cortex is involved in language, thought, perception, and memory, it’s often why a migraine attack trashes one or all of these causing cognitive problems. In MAV the hyperexcitability in the brain stem overlaps with the vestibular system and causes the dizziness/ dysequilibrium/ vertigo. After headache, dizziness and/or vertigo is the second most common symptom associated with migraine.
Scientists are pretty much certain now that CSD explains many if not all aspects of migraine. This model also explains why certain drugs work to prevent migraine, by raising the threshold for aggravating a CSD event. Migraine also involves what is called an “ionopathy” or abnormality of the flow of chemicals in your brain across cell membranes and includes serotonin, dopamine, and noradrenalin. Many migraineurs have lower than normal levels of magnesium, a mineral that plays a role in how calcium behaves and in the regulation of serotonin. Still some migraineurs have problems with calcium channels and explains why a drug like Verapamil (a calcium channel blocker) works for some. Dopamine is yet another brain chemical that some migraineurs have trouble processing. It’s no wonder that given the wide range of biochemical problems associated with migraine that one drug can be effective for one person (SSRI for example which targets serotonin only) and not another – or it may require a two or three-pronged approach to end the attacks in someone with a number of chemical abnormalities. There is, however, no scientific evidence showing that two or more migraine meds is any more effective than one on its own.
All of this makes me wonder why such a genetic problem like migraine even exists at all and why was this not weeded out by evolutionary processes. Clearly the human body is far from perfect and, while the body is an amazing piece of machinery, evolution has certainly left a number of loose ends.
Scott 
