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

[局所的な大脳血流にパルス変調ラジオ周波数電磁界へのばく露は影響する] med./bio.

Exposure to pulse-modulated radio frequency electromagnetic fields affects regional cerebral blood flow.

掲載誌: Eur J Neurosci 2005; 21 (4): 1000-1006

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研究目的(著者による)

To study the effects of radiofrequency electromagnetic fields similar to those emitted by mobile phones on waking 1regional cerebral blood flow in healthy young men.

詳細情報

A previous study restricted to "handset-like" radiofrequency electromagnetic fields (publication 9345) revealed increased relative regional cerebral blood flow in the dorsolateral prefrontal cortex ipsilateral to the side of exposure. In the present study, the effect of a "base station-like" signal (mimicked the signal modulation emitted by a GSM base station) on regional blood flow was investigated and compared with a "handset-like" signal (similar spectral content as the one emitted by GSM mobile phones).

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: continuous for 30 min
  • SAR: 1 W/kg maximum (10 g) (± 14% uncertainty)
  • SAR: 1.5 W/kg maximum (1 g) (± 23% uncertainty)
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) (± 14% uncertainty)
  • SAR: 1.5 W/kg maximum (1 g) (± 23% uncertainty)

General information

The experiments consisted of a double blind sham controlled cross-over design with two active conditions as described in E1 and E2. The intervals between the exposure conditions were at least one week.

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 30 min
Additional information Reference article: R. Huber, T. Graf, K.A. Cote, L. Wittmann, E. Gallmann, D. Matter, J. Schulderer, N. Kuster, A.A. Borbely and P. Achermann (2000) Exposure to pulsed high-frequency electromagnetic field during waking affects human sleep EEG. Neuroreport, 11, 3321-3325 (see publication id 4766).
Modulation
Modulation type pulsed
Pulse width 0.576 ms
Repetition frequency 217 Hz
Additional information

A "handset-like" signal (handset ) was used which had the following characteristics: combination of basic GSM mode and discontinuous transmission mode (DTX) with one of 8 slots active. Basic frame structure of GSM consists of 8 slots (0,..,7). For the handset signal, pulses are active in every slot # 0 except in every 26th frame and, in addition, pulses are active in slots # 1-6 of the frames used in the DTX mode.

ばく露装置
ばく露の発生源/構造
  • two planar antennas
ばく露装置の詳細 The subjects sat on a chair with their heads positioned between the antennas. The left hemisphere of the brain was exposed.
パラメータ
測定量 種別 Method Mass 備考
SAR 1 W/kg maximum 測定値 10 g ± 14% uncertainty
SAR 1.5 W/kg maximum 測定値 1 g ± 23% uncertainty

ばく露2

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 30 min
Modulation
Modulation type pulsed
Pulse width 0.576 ms
Repetition frequency 217 Hz
Additional information

A "base-station like" signal (bstat) (emitted by a GSM base station in communication with 7 mobile phones) was used which had the following characteristics: basic GSM mode and discontinuous transmission mode (DTX) with 7 of 8 slots active. Basic frame structure of GSM consists of 8 slots (0,..,7). For the bstat signal, pulses are active in slots # 0-6, whereas each 26th and 104th frame are modified.

ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
SAR 1 W/kg maximum 測定値 10 g ± 14% uncertainty
SAR 1.5 W/kg maximum 測定値 1 g ± 23% uncertainty

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:
  • ばく露後

研究の主なアウトカム(著者による)

An increase in relative regional cerebral blood flow in the dorsolateral prefrontal cortex on the side of exposure was found. The effect depended on the spectral power in the amplitude modulation of the radiofrequency carrier such that only 'handset-like' radiofrequency electromagnetic field exposure with its stronger low frequency components but not the 'base station-like' radiofrequency electromagnetic field irradiation affected regional cerebral blood flow.
This data supports the authors' previous observation that pulse modulation of radiofrequency electromagnetic field is necessary to induce changes in the waking and sleep EEG, and substantiates the notion that pulse modulation is crucial for radiofrequency electromagnetic field-induced alterations in brain physiology. However, the observed effects of the pulse modulated electromagnetic field were subtle and the underlaying mechanisms remain unknwon. Conclusions about health consequences are premature.

研究の種別:

研究助成

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