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JAMA Cellphone Study May Be Flawed

Several experts have questioned a study that suggested cellphones affect brain activity

2 min read
JAMA Cellphone Study May Be Flawed

When the Journal of the American Medical Association published a study a few months ago that suggested cell phone radiation might increase blood flow in certain brain areas, it madeheadlines. Now that a World Health Organization panel has classified cellphones as possible carcinogens, the JAMA study is making the rounds again. But this time when readers look up the study online they will find three letters from physicists and other experts pointing out what they believe to be significant flaws with the research.

In one of the letters, physicists at the University of Pittsburgh argue that the study authors oversimplified the physics of radiation.

"The authors assumed that the radiofrequency-modulated electromagnetic fields (RF-EMFs) deposited in the brain had an amplitude equal to the electric field of a near-field dipole in a vacuum," they write. "Cell phone antennas are often fractal instead of dipole, significant angular dependence is ignored, and the brain has complicated dielectric properties, which may lead to large differences from the assumed field and invalidate the claimed correlation."

There are also concerns that the results may have been biased--the test subjects were blinded to whether the phones they used were turned off or on, but the researchers were not.

But the critics' biggest complaint seems to be that the effects on brain activity that the researchers observed could have been caused by heat from the phones rather than by radiofrequency fields. In their response to the letters, the study authors argue that the cellphones wouldn't have gotten hot enough during the experiment to affect brain activity. They claim that the temperature increase in the brain would be on the order of 0.1 degrees Celsius at most, citing a 2001 study in IEEE Transactions on Microwave Theory and Techniques. They also argue that the pattern of brain activity would be in different areas if thermal sensation had been the cause.

Christopher Davis and Quirino Balzaro, both researchers at the University of Maryland, College Park's department of electrical and computer engineering, disagree. In their letter, they cite a 2005 study that found thermal heat from active cellphones significantly increased skin temperature on users' faces.

"We believe this study is flawed, as there is no mechanism other than heating by which the radiofrequency fields from a cell phone could affect human tissue," they write, adding, "the authors should have controlled for this temperature difference between the 2 sides of the face to determine whether the heat from the cell phone was the cause of the glucose metabolism changes."

The debate is only bound to intensify as more studies on this subject come out. For journalists and concerned citizens trying to keep track of all the research on cellphones and the brain, it's worth checking the Letters sections of scientific and medical journals to see how these studies are being received by the scientific community. And perhaps the editors of these journals could consider making these dialogues more available to the public, given how much public concern over this issue has grown in recent years.

PHOTO: Vicky TGAW, via Flickr

The Conversation (0)
Illustration showing an astronaut performing mechanical repairs to a satellite uses two extra mechanical arms that project from a backpack.

Extra limbs, controlled by wearable electrode patches that read and interpret neural signals from the user, could have innumerable uses, such as assisting on spacewalk missions to repair satellites.

Chris Philpot

What could you do with an extra limb? Consider a surgeon performing a delicate operation, one that needs her expertise and steady hands—all three of them. As her two biological hands manipulate surgical instruments, a third robotic limb that’s attached to her torso plays a supporting role. Or picture a construction worker who is thankful for his extra robotic hand as it braces the heavy beam he’s fastening into place with his other two hands. Imagine wearing an exoskeleton that would let you handle multiple objects simultaneously, like Spiderman’s Dr. Octopus. Or contemplate the out-there music a composer could write for a pianist who has 12 fingers to spread across the keyboard.

Such scenarios may seem like science fiction, but recent progress in robotics and neuroscience makes extra robotic limbs conceivable with today’s technology. Our research groups at Imperial College London and the University of Freiburg, in Germany, together with partners in the European project NIMA, are now working to figure out whether such augmentation can be realized in practice to extend human abilities. The main questions we’re tackling involve both neuroscience and neurotechnology: Is the human brain capable of controlling additional body parts as effectively as it controls biological parts? And if so, what neural signals can be used for this control?

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