研究のタイプ: 医学/生物学の研究 (experimental study)

[ヒトでのラジオ周波電磁界ばく露:脳でのSAR分布の推定、睡眠と心拍への影響] med./bio.

Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate.

掲載誌: Bioelectromagnetics 2003; 24 (4): 262-276

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研究目的(著者による)

Extended analysis of the effects of radiofrequency electromagnetic field exposure with two different distributions of the SAR on EEG topography and on heart rate. Additionally, detailed dosimetry of the brain areas is presented.

詳細情報

In two previous studies the authors demonstrated that radiofrequency electromagnetic fields similar to those emitted by digital mobile phone handsets affect brain physiology of subjects exposed to radiofrequency electromagnetic fields either during sleep or during the waking period preceding sleep (see publication 758 and publication 4766).
First experiment: Subjects were exposed intermittently during an 8 h nighttime sleep episode (for details see publication 758).
Second experiment: Subjects were exposed unilaterally for 30 min prior to a 3 h daytime sleep episode (for details see publication 4766).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 900 MHz
Modulation type: pulsed
ばく露時間: intermittent, 15 min on/off for 8 h
  • SAR: 1 W/kg maximum (10 g)
ばく露2: 900 MHz
Modulation type: pulsed
ばく露時間: continuous for 30 min
  • SAR: 1 W/kg maximum (10 g)

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
特性
  • near field
ばく露時間 intermittent, 15 min on/off for 8 h
Modulation
Modulation type pulsed
Pulse width 0.577 ms
Duty cycle 12.5 %
Repetition frequency 217 Hz
Additional information

synthesized base station-like signal with seven bursts (slots 0-6) on and one off (slot 7); several frames of the multiframe (104 basic frames) were additionally modified; this signal structure resulted in the spectral components of 2, 8, and 217 Hz, plus the corresponding harmonics; the burst and the intermittency (20 µs) between the bursts led to additional components at 1733 Hz and 50 kHz

ばく露装置
ばく露の発生源/構造
Distance between exposed object and exposure source 30 cm
チャンバの詳細 absorber walls were placed around the antennas and the bed
ばく露装置の詳細 array of three half-wavelength dipole antennas (30 cm apart) mounted behind the head of the recumbent subject at a distance of 30 cm; distance between the top of the subject's head and the antenna array varied during sleep between 30-45 cm and the angle of incidence from -45° to 45°
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
SAR 1 W/kg maximum 備考を参照のこと。 10 g -

ばく露2

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
特性
  • near field
ばく露時間 continuous for 30 min
Modulation
Modulation type pulsed
Additional information

same signal as in E1

ばく露装置
ばく露の発生源/構造
  • planar rectangular patch antennas
Distance between exposed object and exposure source 11 cm
ばく露装置の詳細 antennas mounted at both sides of the head at a distance of 115 ± 5 mm, with the center of the antenna at 42 ± 10 mm vertically above the ear canal
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
SAR 1 W/kg maximum 備考を参照のこと。 10 g -

Reference articles

ばく露を受けた生物:

方法 影響評価項目/測定パラメータ/方法

研究対象とした生物試料:
研究対象とした臓器系:
調査の時期:
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

Compared to sham exposure, spectral power of the non-REM sleep electroencephalogram was initially increased in the 9-14 Hz range in both experiments. No topographical differences with respect to the effect of radiofrequency electromagnetic field exposure were found in the two experiments. Even unilateral irradiation during waking induced a similar effect in both hemispheres. Exposure during sleep reduced waking after sleep onset and affected heart rate variability. Irradiation prior to sleep reduced heart rate during waking and stage 1 sleep.
Simulations of the SAR distribution within the brain support the interpretation that subcortical structures may be responsible for the revealed effect on the sleep EEG.

研究の種別:

研究助成

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