- NEW YORK (Reuters Health) -- Cellular phones emit pulsed high-frequency
electromagnetic fields that may affect the electrical activity in the human
brain in certain situations, according to a study in the October 5th issue
of the journal Neuroreport.
- But German researchers report that the
health effects of their findings are unclear.
- Such phones have not been found to have
an impact on EEG (electroencephalogram) traces, the method used to measure
brain electrical activity. However, in the new study, 13 healthy men in
their 20s were asked to press a button when they heard certain high-frequency
tones in a series of tones emitted every 2 seconds. During the study, a
mobile phone was mounted to the study subject's head, but the subject did
not know when the phone was switched on. While the men were engaged in
the task set, EEG readings were recorded from 30 positions on the scalp.
- After the test was performed several
times, the EEG results were averaged and the researchers found that exposure
to an active cellular phone appeared to influence electrical activity in
the left hemisphere of the brain, that closest to the phone. But this effect
was only noted when the brain was engaged in the task set. No such effect
was seen when the subjects listened to tones not related to the button-pushing
task, report Dr. Carsten Eulitz of the University of Konstanz and colleagues
in Berlin, Germany.
- "This gives further evidence to
the possibility that neural responses as reflected in the EEG can be modulated
through radiation emitted by mobile phones,'' they write.
- But it is not clear what, if any, effect
the phones may have on health, the researchers note.
- "This study does not allow us to
determine any health risk, nor is it clear what behavioral consequences
PEMF (pulsed high-frequency electromagnetic fields) exposure might have,''
- SOURCE: Neuroreport 1998;9:3229-3232.