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

[ヒト脳のα波活動、歯痛閾値、心臓血管パラメータに対する50 Hz磁界が与える影響] med./bio.

Effects of 50 Hz electromagnetic fields on electroencephalographic alpha activity, dental pain threshold and cardiovascular parameters in humans.

掲載誌: Neurosci Lett 2005; 382 (1-2): 112-117

本研究では、α帯域の電気EEG活動(8-13Hz)及び、二重盲検の無作為擬似対照群において、50Hz、40、80μTの磁界に頭部を90分ばく露した後の40名の健康な男性の痛覚への影響を分析した。心臓血管系の調整は、痛み変調に機能的に関係があるので、処置時に血圧BP)と心拍(HR)も測定した。80μTでの磁気処理後のα活動は擬似群と比べて2倍にあった。40μTの磁気処理後の痛覚閾値は、擬似処理後と比べ有意に低かった。BPとHRの影響は見られなかった。結論として、得られた結果はオピオイド系を介しての感覚系のゲート変調で説明でき、ひいては磁界に影響を受けていることが言える。

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研究目的(著者による)

The effects of exposure of subjects to a 50 Hz magnetic field on brain activity, nociception and cardiovascular parameters should be investigated.

詳細情報

Some studies suggest effects of 50 Hz magnetic field exposure on brain activity and nociception, which should be verified. Since cardiovascular regulation is functionally related to pain modulation, some relevant cardiovascular parameters were measured additionally.
40 healthy male subjects participated in the study. Subjects were randomly assigned to one of the two exposure intensity groups (n=20 each; however, only data from 10 subjects from group 1 and 15 subjects from group 2 were analyzed): 1) 40 µT magnetic field and 2) 80 µT magnetic field. Each volunteer was investigated during two sessions at an interval of 1-2 weeks: one exposure session and one sham exposure session. Exposure and sham exposure were conducted in a random order (cross-over study).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 50 Hz
ばく露時間: continuous for 90 min
ばく露2: 50 Hz
ばく露時間: continuous for 90 min

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 90 min
ばく露装置
ばく露の発生源/構造
チャンバの詳細 subject was comfortably seated in a quiet room
ばく露装置の詳細 2 circular coils, similar to Helmholtz coils (44 cm in diameter, each composed of an aluminum ring on which 50 copper coils [0.8 mm diameter] were winded), produced the magnetic field; the coils were positioned around the head of the subject with the head at the center of the coils; the subject was invited to read a magazine during exposure
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 40 µT peak 測定値 - -

ばく露2

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 90 min
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 80 µT peak 測定値 - -

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
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

Brain activity in the alpha wave band was significantly increased after exposure to the 80 µT magnetic field (group 2) compared to the sham exposure.
The pain threshold was significantly lower after exposure to the 40 µT magnetic field (group 1) compared to the sham exposure.
No differences were found in blood pressure, heart rate and hormonal blood levels between exposure and sham exposure in both groups.
The authors conclude, that exposure of subjects to a 50 Hz magnetic field might affect the alpha wave brain activity and nociception, though it is uncertain whether both effects are linked.

研究の種別:

研究助成

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