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Jul 03, 2006

Cell phone emissions excite the brain cortex

Source: Eurekalert
 
Electromagnetic fields from cell phones excite the brain cortex adjacent to it, with potential implications for individuals with epilepsy, or other neurological conditions. This finding is published in Annals of Neurology

More than 500 million people in the world use cell phones which emit electromagnetic fields (EMFs). Though many studies have looked at the effects of EMFs on the body, few have focused on their effects on the brain. Such effects could be harmful, neutral, or beneficial and might be particularly important for individuals with conditions involving cortical excitability, such as epilepsy.

Researchers in Italy, led by Paolo M. Rossini, M.D., Ph.D. of Fatebenefratelli, used Transcranial Magnetic Stimulation (TMS) to investigate brain function under exposure to electromagnetic fields from a common type of cell phone. Their study reports the effects of EMF exposure on brain physiology for the first time.

The researchers developed a double-blind study in which 15 young male volunteers were exposed to EMF signals from a GSM 900 cell phone for 45 minutes. They measured Motor Evoked Potentials (MEPs) during motor cortex TMS before, and immediately after EMF exposure, and also one hour later.

In 12 of the 15 subjects, the data showed an excitability change in the motor cortex adjacent to the cell phone. "Intracortical excitability was significantly modified, short intracortical inhibition was reduced and facilitation enhanced," the authors report. They found that the effects of the EMF were transient and the subjects' brains tended to return toward baseline conditions one hour after the exposure.

It would be premature to presume that this work implies that using a cell phone is bad for the brain in any way. Much more work needs to be done to understand whether these electrical changes in the brain make any difference whatsoever in the way we think or in any disease process in which cortical excitability is affected.

 

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Article: "Mobile phone emissions and human brain excitability." Ferreri, Florinda; Curcio, Giuseppe; Pasqualetti, Patrizio; De Gennaro, Luigi; Fini, Rita; Rossini, Paolo. Annals of Neurology; July 2006; (DOI: 10.1002/ana.20906 ).
 
Abstract

Objective
To test - via Transcranial Magnetic Stimulation (TMS) - the excitability of each brain hemisphere after real or sham exposure to the electromagnetic field (EMF) generated by a mobile phone operating in the Global System for Mobile Communication (GSM).

Methods
Fifteen male volunteers attended two experimental sessions, one week apart, in a cross-over, double-blind paradigm. In one session the signal was turned ON (EMF-on, real exposure), in the other it was turned OFF (EMF-off, sham exposure), for 45 minutes. Motor Evoked Potentials (MEPs) were recorded using a paired-pulse paradigm (testing intracortical excitability with 1 to 17 ms interstimulus intervals), both before and at different times after exposure to the EMF. Short Intracortical Inhibition (SICI) and Facilitation (ICF) curves were evaluated both on the exposed and non-exposed hemispheres. Tympanic temperature was collected during each session.

Results
The intracortical excitability curve becomes significantly modified during real exposure, with SICI being reduced and ICF enhanced in the acutely exposed brain hemisphere as compared to the contralateral, non-exposed hemisphere or to sham exposure. Tympanic temperature showed no significant main effect or interactions.
 

 

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