Volkow, N. D.; Tomasi, D.; Wang, G. J.; Vaska, P.; Fowler, J. S.; Telang, F.; Alexoff, D.; Logan, J., and Wong, C. Effects of cell phone
radiofrequency signal exposure on brain glucose metabolism. JAMA. 2011 Feb 23; 305(8):808-13
Studies of acute effects of radiofrequency-modulated electromagnetic fields (RF-EMFs) on brain function in humans have produced inconsistent results. For example, studies using positron emission tomography (PET) reported increases, decreases or no changes in cerebral blood flow with RF-EMF exposure. These discrepancies show the need for further studies. Brain glucose metabolism may be a better marker of neuronal activity than cerebral blood flow which reflects not only neuronal but also vascular components.
The objective of this study was to investigate effects of acute cell phone exposure on brain glucose metabolism as a marker of brain activity
Forty seven healthy participants (23 men and 24 women, average age 31 years) were recruited from the community. Glucose metabolism was measured using PET scans with injections of (18F) fluorodeoxyglucose (18FDG). Two cell phones, one placed on the left ear and one on the right, were used in order to rule out confounding effects from the expectation of the signal on the side of the cell phone placement. Two PET scans were performed on two separate days. On one of these days, both cell phones were deactivated (“off” condition), and on the other day the right cell phone was “on” (sound muted to avoid auditory stimulation) for 50 min. The frequency of the EMF emitted by the cell phone was 837.8 MHz, and the maximum specific absorption rate for this phone model was 0.3 W/kg. The order of exposure conditions was randomized, and the participants were unaware of the condition.
There was no difference in whole-brain glucose metabolism between the two exposure conditions. However, there were significant regional differences. Glucose metabolism in the brain region closest to the antenna was significantly higher for “on” than for “off” conditions. The increases in glucose metabolism were significantly positively correlated with the amplitude of the electric field produced by the mobile phone.
Interpretation and Conclusion
The results show that acute exposure to EMFs from cell phones affects brain function. Clinical significance of these findings is unclear. Further studies are needed to assess potential long-term consequences of the observed effect.