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

[携帯電話放射ラジオ周波数電磁界へのばく露後のヒトの脳活動] med./bio.

Human brain activity during exposure to radiofrequency fields emitted by cellular phones

著者: Hietanen M, Kovala T, Hämäläinen AM
掲載誌: Scand J Work Environ Health 2000; 26 (2): 87-92
RISフォーマットで参考文献をダウンロード

この研究は、高周波（RF）電磁界ばく露がヒトの脳機能に影響を与えるか否かを調べた。男性10人（28〜48歳）、女性9人（32〜57歳）のボランティアを被験者に用いた実験で、ばく露または擬似ばく露中の脳電図（EEG）活動を定量的に分析した。ばく露発生源として、900 MHzまたは1800 MHzの周波数で動作する5種類の携帯電話（アナログおよびデジタルモデル）を用いた。EEGは覚醒、閉眼で記録した。各被験者に、30分間のばく露実験を6回（5種類の携帯電話によるばく露と１回の擬似ばく露）行った。30分間のうち、実際のばく露時間は20分間であった。その結果：１種類の電話によるばく露において、デルタバンドの絶対パワーに有意な変化が見られた；ただし、同じバンドの相対的パワーに変化はなかった；これ以外の周波数バンドでも何らの変化はなかった；結論として、携帯電話からの高周波電磁界ばく露がヒトのEEG活動に異常な影響を及ぼすことはないことが示された；一つのパラメータについて観察された変化は、おそらく統計的な偶然によるものと考えられる、と報告している。

The detailed summary of this article is not available in your language or incomplete. Would you like to see a complete translation of the summary? Then please contact us →

研究目的（著者による）

To explore the possible influence of radiofrequency fields (emitted by 5 different cellular phones) on human brain functions.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 900–1,800 MHz
ばく露時間: repeated exposure trials for 30 min with 20 min of real exposure

ばく露1

主たる特性
周波数 900–1,800 MHz
タイプ
  • electromagnetic field
ばく露時間 repeated exposure trials for 30 min with 20 min of real exposure
Additional information Four mobile phones operated at 900 MHz and one at 1800 MHz.
Modulation
Modulation type cf. additional information
Additional information

NMT, GSM, or PCN
ばく露装置
ばく露の発生源／構造
  • セルラ－電話
  • see setup details
Distance between exposed object and exposure source 1 cm
ばく露装置の詳細 Three different analogue 900 MHz NMT phones were used with either a helix, fixed whip, or extended whip antenna as well as two digital phones operating at 900 MHz (GSM) and at 1800 MHz (PCN), respectively. The phones were operated via a computer and without sound transmission (single-blind). The phones which were not held by the test persons were located 1 ± 0.5 cm from the head while the subjects were seated in a comfortable chair.
Additional information Five exposure trials of 30 min were performed each with 20 min of RF exposure and 5 min of sham exposure before and after the real exposure. Apart from this there was a separate 30 min sham exposure trial. The order of different exposure conditions was randomised. Only one test per day was done for each subject.
パラメータ
測定量 値 種別 Method Mass 備考
電力 2 W - - - 1-2 W
SAR 850 mW/g - 測定値および計算値 10 g 0.851-0.818 mW/g
測定および計算の詳細

The functioning of the phones was checked with a power meter at the start and occasionally during the trials. Electric fields inside a liquid phantom head were measured with and without the EEG electrodes attached using an electric field probe, and the calculated SAR values were nearly the same in both cases.

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

研究の主なアウトカム（著者による）

Radiation to one of the phones caused a statistically significant change in the absolute power at the delta band of the EEG recording. However, no difference was found in the relative power of the same band, and no changes occured during radiation to other phones at any frequency bands. The data suggest that exposure to radiofrequency field emitted by cellular phones has no abnormal effects on EEG activity. The observed difference in one parameter was probably caused by statistical chance.

研究の種別:

研究助成

この論文に対するコメント

関連論文