Searching for the cause of 'brain freeze'

It’s possibly the cruelest joke a brain can play: One minute you’re devouring a delicious ice cream sundae in delight, the next you’re holding a palm to your forehead in excruciating pain.

For the next 10 seconds, what you laughingly refer to as “brain freeze” (when other people get it) is no laughing matter.

Researchers induced such pain in 27 healthy volunteers in a new study presented at the Experimental Biology 2012 conference in San Diego this week.

Lead author Jorge Serrador and his team were trying to identify exactly what causes brain freeze. They hoped that by pinpointing the cause they would influence future research on migraines or post-traumatic headaches.

Approximately 10% of the population suffers from migraines, according to Cathy Glaser, president of the Migraine Research Foundation, which was not associated with the study. “We do not know what causes migraines... there are a lot of theories around, but that’s why basic research is so essential.”

It’s certainly not a new field. Since the late 1970s, researchers like Dr. Neil Raskin and Joseph Hulihan have been studying brain freeze - also called an “ice cream headache” or “sphenopalatine ganglioneuralgia” - as a way to identify the cause of headaches. This phenomenon is easy to investigate because it can be brought on without drugs, and resolves quickly on its own.

Serrador’s team had each volunteer drink ice water from a straw pressed against the roof of his or her mouth – optimal placement to induce brain freeze. The volunteers then raised a hand when they felt pain, stopped drinking and then raised a hand again when the pain disappeared.

Using a transcranial Doppler, the researchers measured the velocity of blood flow through the brain’s blood vessels.

Blood flow increased significantly in the anterior cerebral artery when the volunteers felt pain. This artery feeds the brain’s frontal lobe (remember the palm to your forehead?). The artery then constricted as the volunteers’ pain subsided.

“We’re not sure what might be causing the pain itself,” Serrador said.

One possible reason is the increase in pressure that’s associated with the influx of blood flow to the frontal lobe, he said. The ice water could also be hitting the trigeminal nerve in your upper palate, which would deliver pain messages to the brain. Or the brain could just be susceptible to temperature.

More sophisticated research is needed, said Dr. Seymour Diamond, executive chairman and co-founder of the National Headache Foundation. Although a few studies have shown a link between people who get migraines and those who suffer from brain freeze, more have shown no link at all.

“I’m wary of the results,” he said. “I don’t think this is going to be a breakthrough for migraine or post-concussion headaches.”

Serrador plans to continue researching the topic. His next step is to block the trigeminal nerve during testing to see if that would eliminate the brain freeze phenomenon or if the increased blood flow would still cause pain.