"Calls account for 80% of the radiation received and affect the memory of young people"

What are the effects of high frequency electromagnetic fields on our health, especially those of mobile phones, of which this is the most important source? This is the question posed for several years by the "Environmental and Health Expositions" unit at the Swiss Institute of Tropical Health and Public Health (Swiss TPH), attached to the University of Basel.

The study published this Thursday, July 19 in the journal Environmental Health Perspectives reports the information obtained on the follow-up of the intellectual performance of nearly 900 Swiss adolescents according to their behavior with their mobile phone. Martin Röösli, the professor responsible for research, explains the main results, before concluding on the actions to be taken to protect us.

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The Time: The main source of exposure to high frequency electromagnetic fields is the mobile phone. What effects did you have on the activity of our brain?

Martin Röösli: We tested different aspects of memory performance in adolescents according to the uses that they were doing their mobile phone. The clearest statistical result is that "memory", which is governed by a brain area to the right of the head, would be affected by the radiation emitted by mobile phones, especially during calls. The result is the most marked in people who hold their phone against the right ear.

What exactly is the memory figurale?

To explain it in a simple way, it s' is the memory of forms. The tests we gave to the young people were either groups of words or abstract forms to memorize. These are the results relating to the forms that are the most deteriorated in adolescents being most exposed to electromagnetic waves.

Other studies have been done on the question, what does your research bring from new

Observing the effects on memory seemed to be the best approach for studying the effects of mobile phones on our brain in the medium and long term. It is at this scale that one can observe the effect of cumulative exposure to waves, whereas most experimental studies are carried out over very short periods of time.

Moreover, the originality of our work has three aspects. We followed groups of adolescents over several years, testing them several months apart. We then developed a model for calculating brain exposure and cumulative dose for different uses (call, text message, web browsing, gaming …). It was thus possible to measure that it is the calls, holding the telephone by the ear, which constitute 80% of the radiation received. Finally, for part of our sample, we were allowed access to the data recorded by the telephone operators, which was a real plus, as the estimates of the teenagers tend to be overestimated. This data has therefore strongly contributed to the robustness of our results.

Why choose A sample of teenagers?

There is a twofold interest in the studied adolescents, aged 12 to 17: their memory is still in training and they use their phone more than younger children. And even if they prefer text messages (35 messages per day averaged over the sample) and spend so few calls, the results of the study are significant.

Your study highlights a statistical link, but no cause-and-effect relationship has been demonstrated by your work. How can these results be further substantiated?

To prove a causal link, neurobiologists would have to look into this problem in order to study the mechanisms at work as a result of the scale of the cells of our brain. Overheating phenomena or oxidative stress have already been observed, but never on the human being, nor in direct connection with specific activities such as the use of the mobile phone.

What good practices can be advised to the population? Do they depend on people's age, or are they the same for everyone?

Anyone can take simple steps to limit their brain's exposure to mobile phone radiation. For example, it is estimated that using the loudspeaker, headphones, or a hands-free kit reduces the exposure by a factor of 10. It is also important to avoid making calls when the connection is bad, for a minute is equivalent to several hours spent on the telephone by ear under normal conditions.