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

[安静時EEGはELFパルス磁界ばく露に影響される] med./bio.

Resting EEG is affected by exposure to a pulsed ELF magnetic field.

掲載誌: Bioelectromagnetics 2004; 25 (3): 196-203

この研究は、周波数0から500 Hzの範囲に大部分のパワーがあるパルス超低周波磁界(ELF MF)へのばく露が、ヒトの脳電図(EEG)に影響するか否かを調べた。20人の被験者(男性10人、女性10人)に、磁界MFばく露セッション擬似ばく露セッション(どちらも15分間)の両方をカウンターバランスさせて受けさせた。分散分析ANOVA)の結果、ばく露後のアルファ波活動は、後頭部電極(O1、Oz、O2)で有意に高く、頭頂電極(P3、Pz、P4)でわずかに高かった;アルファ波活動の増強は一過性であり、ばく露から約7分後には、後頭部および頭頂部で擬似ばく露に比べわずかに低下した、と報告している。

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研究目的(acc. to editor)

To study the effects of extremely low frequency magnetic fields with most power at frequencies between 0 and 500 Hz on the human EEG.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 0–500 Hz
Modulation type: pulsed
ばく露時間: intermittent for 15 min, see Modulation

ばく露1

主たる特性
周波数 0–500 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 intermittent for 15 min, see Modulation
Additional information The power content was extremely low above 500 Hz with most of the power content below 300 Hz.
Modulation
Modulation type pulsed
Rise time 1 ms
Pulse type biphasic
Additional information

The (patented) pulsed MF design was made of individual pulses, each of which a doublet, combined in an 853 ms segment including 18 pulses. Each pulse had a maximum rise time of 1 ms resulting in a maximum time changing MF of 0.4 T/s. In between segments were varying refractory periods of 110, 220, 330 ms followed by a longer fourth refractory period of 1200 ms after which another pulse segment of 853 ms began. This pattern was repeated for 15 min.

ばく露装置
ばく露の発生源/構造
チャンバの詳細 The MF exposure system [Thomas et al., 2001] consisted of three orthogonal square Helmholtz-like coil pairs with 2, 1.75, and 1.5 m sides (10 turns of 8-gauge stranded conductor per coil with an incorporated high temperature, non-conductive cooling/heating tube wound on Lexan® frames). During exposure, only the vertical coil pair was driven by a constant current amplifier via a digital to analog converter; all other coils were unpowered. During sham exposure, the amplifiers were on but there was no signal.
ばく露装置の詳細 Subjects were fitted with the EEG recording apparatus (cap) and seated within the exposure system. They were instructed to relax, but to not fall asleep.
Sham exposure A sham exposure was conducted.
Additional information Twenty subjects received both an MF and a sham session approx. 1 week apart, in a random, counterbalanced, cross-over design. The experiment consisted of 5 min of pre-exposure baseline EEG followed by either 15 min of MF or sham exposure. Due to the interference of the pulsed MF with the recording, EEG was sampled approximately 7 s after the end of the MF or sham condition.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 200 µT peak 測定値 - biphasic

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:
  • ばく露前
  • ばく露後

研究の主なアウトカム(著者による)

Exposure to a specific pulsed extremely low frequency magnetic field was revealed to result in higher resting EEG alpha wave activity (8-13 Hz) compared to sham exposure.
The authors suggest that this result may be a nonspecific physiological response to the pulsed magnetic fields.

研究の種別:

研究助成

Replication studies

関連論文