We all know that using a cell phone can stimulate the brain to work a bit harder. “Mr. Skerrett? This is Dr. LeWine’s office. Do you have a minute to talk about your test results?” or “Dad, a bunch of kids are going to Casey’s house after the dance. Can I go?” But a new study published in JAMA is making me wonder what the energy emitted by the phone itself — not just the information it delivers — is doing to my brain.
Here’s the study in a nutshell. Dr. Nora Volkow and her colleagues recruited 47 volunteers to have their brain activity measured twice by a PET scanner. Both times the volunteer had a cell phone strapped to each ear. During one measurement, both phones were turned off. During the other, one phone was turned on but muted so the volunteer didn’t know it was on; the other was left off. Each session lasted about an hour. The scans showed a small increase in the brain’s use of glucose (blood sugar) when the phone was on, but only in parts of the brain close to the antenna.
It was an elegant study. The researchers took pains to anticipate sources of error. They used a control (both phones off) against which to compare the effect of a “live” cell phone. They used cell phones on each ear, one on and one off, to see if the effect was localized. They muted the phone that was on to eliminate the possibility that any brain activation was due to listening to the sound of a voice coming through the phone’s speaker. So the result is probably a real one, not an artifact or measurement error.
What does this brain activation mean? No one really knows. As Dr. Volkow told NPR, “I cannot say if it is bad that they [cell phones] are increasing glucose metabolism, or if it could be good.”
The big worry, of course, is brain cancer, not brain activation. It’s a controversial and hotly-debated topic. But with conflicting evidence linking cell phone use with brain cancer, this study will probably push the debate in both directions. Some will see the results as reassuring — the brain activation during the 50 minutes the one cell phone was on was less than that seen when you open your eyes or listen to music. Others will see the brain activation as a possible early step toward cancer.
I’m with Dr. Volkow and others who think that this study means it’s worth taking a closer look at how the energy radiated by a cell phone, a mobile phone, or any other energy-emitting device we hold next to our heads may affect the brain. I’m also going to avoid 50-minute conversations by cell phone (the duration in the study) and save those for when I’m using a headset or my old-fashioned, noncordless land line.
- P.J. Skerrett, Editor, Harvard Heart Letter
*This blog post was originally published at Harvard Health Blog*