To study whether exposure to radiofrequency caused by cell phone use has any acute effect on self-reported symptoms (e.g. headache, vertigo) and whether subjects are able to accurately detect the correct exposure status (exposure vs. sham exposure).
Modulation type: pulsed
Exposure duration: continuous for 3 h
The study followed a double blind, cross-over provocation design testing exposure versus sham. The exposure setup was designed to expose all those head tissues that are exposed in daily phone usage, taking into account the range of phone designs, reasonable phone positions and head anatomies [Kuster et al., 2004], and the exposure was also intended to provide a similar tissue specific exposure distribution as applied by Huber et al. .
|Exposure duration||continuous for 3 h|
|Chamber||Two subjects participating in each session were seated in two adjacent unshielded rooms (5.1 m x 3.6 m and 5.1 m x 2.5 m, respectively) with RF absorbers placed on three sides. The exposure conditions were set to be the same for both participants during a session in order to avoid an influence of any possible leakage of fields.|
|Setup||The exposure apparatus consisted of a balanced headset positioning a low-weight, stacked micro patch antenna on the left side of the subject's head.|
|Sham exposure||A sham exposure was conducted.|
|Additional info||To mimic the sensation caused by the active phone, a small ceramic plate connected to the left ear lobe was heated to 39 ± 0.2 °C by a laser during all exposure sessions.|
|SAR||1.4 W/kg||average over time||measured and calculated||10 g||spatial peak for all head tissues|
|SAR||1.8 W/kg||average over time||measured and calculated||1 g||spatial peak for grey matter|
|SAR||0.2 W/kg||average over mass||measured and calculated||brain||± 0.26 W/kg grey matter|
|SAR||0.18 W/kg||average over mass||measured and calculated||brain||e: ± 0.21 W/kg white matter d: ± 0,21 W/kg weiße Substanz|
|SAR||0.18 W/kg||average over mass||measured and calculated||brain||± 0.06 W/kg thalamus|
The data showed that headache was more commonly reported after exposure than sham exposure, mainly due to an increase in the non-symptom group (control group).
Neither group could detect radiofrequency exposure better than by chance.
A belief that the radiofrequency irradiation had been active was associated with skin symptoms.
Further investigation of the higher prevalence of headache in the non-symptom group and a possible physiological correlation should be performed.
The findings indicate a need to better characterize subjects in cell phone exposure studies and differences between symptom and non-symptom groups.