Saturday, October 20, 2012

Brain Freeeeeeeze (Marin IJ)

It’s popsicle-o-clock at the Ballard house and everyone is content… until a horrible shriek reverberates through the home. The perpetrator is three-year-old Holden and his tribal yell quickly morphs into a plaintative wail of “brain freeeeeeeeezzzzze.” In a moment, the pain (for all of us) recedes and our daughter, removing her hands from her ears, asks, “Dad, what causes ‘brain freeze?’” Until recently I would have answered: “Popsicles.” But now, thanks to new evidence, I can instead tell her, “vasodilatation of the anterior cerebral artery.”

This past April, Jorge Serrador of Harvard Medical School and colleagues reported the results of a small study suggesting an explanation for the bodily processes (physiology) involved with brain freeze (known in medicalese as sphenopalatine ganglioneuralgia.) Now, I know what you might be thinking – with autism unexplained and cancer uncured, aren’t there greater priorities for medical research than a painful yet benign experience like sphenopalatine ganglioneuralgia? And, you would be absolutely right. However, there is a bit more to it, and some have long posited that the physiology of brain freeze might be related to that of other (less temporary) conditions – such as post-traumatic and migraine headaches. In fact, prior studies have suggested that migraine sufferers are more likely than other folks to experience brain freeze. So, with that in mind, let’s get back to the research at hand.

Serrador and colleagues recruited thirteen healthy adults willing to suffer through brain freeze in the name of science (and I’m guessing there were other inducements as well). While researchers monitored the blood flow in their brains with transcranial Doppler (ultrasound), the volunteers sipped ice water through straws pressed against their upper palates. Then, they raised their hands to signal the freeze and thaw of brain freeze. Brain blood flow under these conditions was then compared with that of the same volunteers sipping warm water. The results of the study were presented at the Experimental Biology 2012 conference in San Diego and were notable in that the researchers observed that one particular artery, the anterior cerebral artery, dilated rapidly and flooded the brain with blood in conjunction with the freeze sensation. Soon after this vasodilatation occurred, the same vessel constricted (tightened) as the volunteers' pain receded. Now, remember, this was a small study and it’s results have yet to complete the rigorous peer review process associated with manuscript publication. Nonetheless, there do seem to be some important implications in these findings.

1)     Migraine headaches. These are thought to be caused by abnormal dilation of arteries in the brain, and many existing treatments attempt to modulate this process. These results then, support this concept and may lead to greater focus on migraine treatments that prevent dilation in the first place. And, for people with friends or family members with migraines, this study provides us with a way to relate to their pain. For some with migraines, the headache must certainly feel like one long brain freeze. Ouch.

2)     The suddenness of sensation matters. We’ve all heard about the frog that will jump out of a pot of boiling water but will stay in a tub slowly brought from ambient temperature to a boil. One of the aspects of brain freeze that makes it so uncomfortable is the rapidity and severity of its onset. This principle is worth keeping in mind for other situations. Take, for example, removing a bandage. The conventional wisdom is that pulling it off quickly is better, as it gets the pain over and done with. But some researchers, such as Dan Ariely, the author of the fascinating book Predictably Irrational, contend the opposite; the quicker the pain the more severe the pain, and thus the greater the overall discomfort. So perhaps very slowly removing a band-aid is actually more comfortable than yanking it right on off. That’s a topic to be exposed more thoroughly some other time.

3)     Now, I can turn Holden’s occasional freezathon into a spelling lesson for his sister. Ok, here we go, let’s try “sphenopalatine ganglioneuralgia.” S...P...H…