After however long Sci has been in the blogsphere, I think I've become inured to the near constant babble of breathless science reporting. Oral contraceptives CHANGE YOUR BRAIN!! You are yourself...ON HORMONES. Cell phones cause brain cancer! TIDAL WAVES of hormones. TSUNAMIS of brain activity! A veritable STORM SURGE of wave metaphors have invaded our science reporting, folks. But then I think, meh, you know, it's just another report from someone who just read an already breathlessly written press release, it'll all work itself out, and I just can't get worked up anymore...I need another latte...
And then I see this kind of thing:
Power-talkers with cell phones glued to their ears may be getting more than conversation.
Do cell phones cause cancer?
We'd all like to know, but unfortunately there's no clear answer — yet.
And then it's coupled with things like "brain metabolism", "brain activity", and my current favorite (emphasis mine):
higher rates of glucose metabolism in the brain can mean a number of things. Yes, tumor cells may gobble up more glucose to fuel their relentless growth, but healthy brain cells need constant replenishment too, to keep up the intricate network of messages and connections that help us think, eat, move and stay alive.
Yeah, it COULD be your greedy TUMOR CELLS gobbling up your BRAIN ENERGY!!! Or it could be something else!
I feel comforted now. You?
But just in case...
Volkow et al. "Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Metabolism" JAMA, 2011.
People are concerned about the effects of cell phones on your brain. They are also concerned about microwaves effects on your brain (did you know there are people out there who really think microwaves control your MIND?!), the effects of laptops on your balls, the effects of chemicals in your water bottles, and the list goes on. Many of these things may indeed be of concern. Man, if technology didn't mean a 15-20 year increase in average life expectancy and a drastic increase in perceived quality of life, what crapola it would be.
I'm being flippant, obviously. We do tend to make and discover cool things first and figure out they are bad for us later (see Radium for one of my personal favorites). And it seems like everyone these days owns a cell phone. And you can't deny that when you've been on them for a while and the little buggers get kind of warm, you start to worry a little.
You may not be wrong to worry. But the JURY IS STILL OUT. Despite quotes like these:
Some studies have linked cell phone exposure to an increased risk of brain cancers, but a large study by the World Health Organization was inconclusive.
The current information is no cause for panic. In fact, the above quote is misleading. Unless by "a large study by the World Health Organization was inconclusive" they MEAN "a large study be the World Health organization found no correlation". Inconclusive sounds scarier, I guess.
Anyway, we really DON'T know whether prolonged use of cell phones when applied directly to the ear is bad for you or not. This study DOES NOT ADDRESS whether prolonged use of cell phones on the ear is bad for you or not. What it DOES address is whether or not cell phones can in fact change brain activity.
To look at this, they took 47 people, and ran PET studies on them, looking at glucose utilization. What happens here is that a person is injected (usually, though I think you can actually take it in a drink) with a solution containing a small amount of radioactively marked glucose. The radioactivity in the molecule will give off gamma rays, detected by a machine. You can then use the concentration of gamma rays in various areas to suggest where large amounts of glucose are being moved in the brain by cerebral blood flow. The general idea is that where the blood is going, there goeth the activity.
In this case, they looked at glucose utilization over two days of studies. The participant would get two cell phones strapped on either ear and hung out in the PET machine for an hour. On one day (the order was randomized), both cell phones were off. On the other day, the RIGHT cell phone was ON, and receiving a message, but was on mute so the participant couldn't hear anything (and so you wouldn't see brain activity resulting from what the participant was hearing). The cell phone was the Samsung Knack Flip phone.
Here's what they got:
This figure shows the radiofrequency field of the antenna of the cell phones. According to the radiofrequency of the on cell phone looks like it hits the low part of the temporal gyrus the most, with some effects on the orbitofrantal gyrus.
When they ran the PET, this is what they got:
This here is a representative brain image of glucose metabolism during the "off" (right) and "on" (left) cell phone conditions. What they saw was an increase (in total of about 7%) of glucose metabolism in the orbitofrontal cortex. No increases in total brain glucose metabolism (7% in one area is too small to affect the glucose metabolism of the brain as a whole).
That's it. That's ALL. What can we infer from this? That the presence of an "on" cell phone increases glucose metabolism on the side of the orbitofrontal cortex where it is held. The authors hypothesize that the electrical potentials from the cell phones may be affecting things like membrane potentials in this area, possibly making it more active. It IS an affect on brain metabolic activity in that area.
What does that mean? Dang if I know, and dang if they know either. They do note that there's an increase in brain metabolic activity, but no one has ANY idea if this could have anything to do with cancer.
I think this is an interesting study, and I think, like the authors, that this should make people want to learn more. But I also have some questions.
1) Why did they get increased glucose metabolism in the orbitofrontal cortex, but apparently NOT in the inferior temporal gyrus? It seems that the radiofrequency was highest there, so if it was a direct effect on metabolism like they conclude with the orbitofrontal cortex, I wonder why they didn't see anything in the temporal gyrus.
2) What about HEAT? One of the articles covering the paper stated that it couldn't be head because it occurred near the antenna rather than where the phone touched the head, but this isn't mentioned in the paper itself (or at least I didn't find it). I would kind of like to see measurements of heat as well as radiofrequency, and see how they correlate (or not) with changes in activity. Even if there's no effect, it's a good control to have.
Finally, keep in mind. It's a 7% change in glucose metabolism. That is TINY. You get larger increases when you think about Disney Hipsters (really I just had to put that link in there because I love it!). So I wonder if this increase really does have any meaningful effect. It's an increase in glucose metabolism, yes. But it's going to take WAY more information before we know what these changes mean, and even talking about cancer seems more than two steps ahead at this point.
EVERY bit of coverage ends with the note that Dr. Volkow uses a handsfree. Her thought is, why take any risk at all? I agree with her, but not for brain metabolism, rather I worry about the probably much LARGER risk to your driving. So get the handsfree anyway.
Nora D. Volkow, MD, Dardo Tomasi, PhD, Gene-Jack Wang, MD, Paul Vaska, PhD, Joanna S. Fowler, PhD, Frank Telang, MD, Dave Alexoff, BSE, Jean Logan, PhD, & Christopher Wong, MS (2011). Effects of Cell Phone Radiofrequency Signal
Exposure on Brain Glucose Metabolism JAMA, 305 (8) DOI: 2011;305(8):808-814