This study was designed to investigate the acute effects of radio frequency electromagnetic fields emitted by UMTS mobile phone base stations on human cognitive function and symptoms in vivo.
Adolescents (mean age: 15.7 years; 17 males, 23 females) and adults (mean age: 31.1 years; 24 males, 16 females), neurologically healthy were selected for this study. During exposure the participants performed different cognitive tasks (amongst others "Trail Making B" test) and completed a questionnaire measuring self reported subjective symptoms. In the applied "Trail Making B" test the participants had to draw lines alternating beween numbers and letters in consecutive order. The time at which the task was completed correctly was measured.
| Exposure | Parameters |
|---|---|
|
Exposure 1:
2,140 MHz
Modulation type:
CW
Exposure duration:
continuous for 45 min
|
|
|
Exposure 2:
2,140 MHz
Exposure duration:
continuous for 45 min
|
|
All participants attended four exposure sessions on separate days at the same time of day. They were exposed to four conditions: sham, CW, a signal modulated as UMTS, and UMTS including all control features in a randomized, double blinded cross-over design.
| Frequency | 2,140 MHz |
|---|---|
| Type | |
| Polarization | |
| Exposure duration | continuous for 45 min |
| Additional info | plane wave with vertical polarization |
| Modulation type | CW |
|---|
| Exposure source | |
|---|---|
| Distance between exposed object and exposure source | 2.8 m |
| Chamber | The study was performed under controlled conditions in a shielded 33.4 m³ climate chamber made of aluminium with walls, floor, and ceiling partly covered with RF absorbers. All cables to and from the chamber were filtered and mounted with ferrite beads to suppress common mode signals. All lighting in the room was from light-fibres or from a 12 V DC source, and all electronic devices were supplied by 12 V DC. |
| Setup | The participants were seated on a chair at a wooden table next to a computer and keyboard. |
| Sham exposure | A sham exposure was conducted. |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| electric field strength | 2.2 V/m | maximum | measured | - | - |
| electric field strength | 1.5 V/m | minimum | measured | - | limited area |
| electric field strength | 0.9 V/m | minimum | measured | - | total area |
| power density | 2.6 mW/m² | - | - | - | target value |
| Frequency | 2,140 MHz |
|---|---|
| Type | |
| Polarization | |
| Exposure duration | continuous for 45 min |
| Additional info | plane wave with vertical polarization |
| Exposure source |
|
|---|---|
| Distance between exposed object and exposure source | 2.8 m |
| Additional info | The CW modulated as UMTS was generated by setting the control channels to the lowest level (P-SCH, S-SCH, P-CCPCH, and the PICH channel). The UMTS signal was generated by initiating a live connection to a mobile phone through a 10 dB coupler and then filtering only the base station signal to the exposure antenna. |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| electric field strength | 2.2 V/m | maximum | measured | - | - |
| electric field strength | 1.5 V/m | minimum | measured | - | limited area |
| electric field strength | 0.9 V/m | minimum | measured | - | total area |
| power density | 2.6 mW/m² | - | - | - | target value |
No statistically significant differences between the UMTS and sham exposure were found in any of the cognitive tests or self reported symptoms in both adolescents and adults.
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