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

[携帯電話から放射される電磁界は前庭器官を刺激できるか？] med./bio.

Can electromagnetic fields emitted by mobile phones stimulate the vestibular organ?

著者: Pau HW, Sievert U, Eggert S, Wild W
掲載誌: Otolaryngol Head Neck Surg 2005; 132 (1): 43-49
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この研究は、携帯電話からの電磁（EM）放射で耳に生じる温度上昇が、前庭器官の興奮を引き起こすのに十分な大きさか否かをヒトボランティア実験で調べた。13人のボランティア（26耳）を対象に、シミュレートされたGSM信号（889.6 MHz、2.2 W）ばく露を一度に1つの耳に与え、ビデオ方式で眼振計測記録を行なった。実験装置は、温水・冷水を用いた前提器官周辺組織の温度刺激眼振試験と同じものである。データはコンピューターシステムによって評価された。また追加の実験で、連続またはパルス変調のEM放射ばく露を受けているヒトの側頭骨の温度をサーモグラフィーで測定した。その結果、どの被験者においても、EM放射が誘発する眼振を記録できなかった；このことは、ヒト側頭骨における温度上昇効果が、放射源（携帯電話のアンテナ）に隣接する組織層でしか見られなかったことと対応する；温度上昇効果は、より深い領域（水平半規管）は影響を受けなかったように見えた（少なくとも0.1℃未満）、と報告している。

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研究目的（著者による）

1) To attempt to detect nystagmus during exposure to electromagnetic fields from a standardized irradiation source similar to a mobile phone.
2) To attempt to determine the dimension of thermal effects on the outer surface of the mobile phone and on tissues exposed to its electromagnetic irradiation.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 889.6 MHz
Modulation type: pulsed
  • 電力: 2.2 W peak (at the feeding point)
  • 電力: 0.275 W mean (at the feeding point)
  • SAR: 1.9 mW/g average over mass (1 g) (below the skin)
  • SAR: 1.93 mW/g average over mass (1 g) (18 mm deep)
ばく露2: 889.6 MHz
Modulation type: CW
  • 電力: 0.275 W mean (at the feeding point)
  • SAR: 1.9 mW/g average over mass (1 g) (below the skin)
  • SAR: 1.93 mW/g average over mass (1 g) (18 mm deep)
ばく露3: 889.6 MHz
Modulation type: pulsed
ばく露時間: continuous for 15 min
  • 電力: 2.2 W peak (at the feeding point)
  • 電力: 0.275 W mean (at the feeding point)
ばく露4: 889.6 MHz
Modulation type: CW
ばく露時間: continuous for 15 min
  • 電力: 2.2 W peak (at the feeding point)

ばく露1

主たる特性
周波数 889.6 MHz
タイプ
  • electromagnetic field
Modulation
Modulation type pulsed
Pulse width 576 µs
Repetition frequency 217 Hz
Additional information

frame length of 4.61 ms
ばく露装置
ばく露の発生源／構造
  • セルラ－電話
  • RF generator
チャンバの詳細 The test person was in a lying position, the upper part of the body being raised to 30 degrees.
ばく露装置の詳細 Mobile phones connected to an external RF power supply were fixed to both sides of an adjustable chair and could be switched on alternatively.
Additional information Tests were carried out each ear at a time with or without continuous or pulsed EMF, resulting in 4 measurements for each inner ear (8 tests for each individual).
パラメータ
測定量 値 種別 Method Mass 備考
電力 2.2 W peak 測定値 - at the feeding point
電力 0.275 W mean 測定値 - at the feeding point
SAR 1.9 mW/g average over mass 測定値 1 g below the skin
SAR 1.93 mW/g average over mass 測定値 1 g 18 mm deep
測定および計算の詳細

RF power supplied by the generator to the connection sockets of the phones was routinely controlled before and after the test by a power meter with measuring head and upstream 30-dB attenuator. SAR was measured by T-Systems using the DASY-2 system.

ばく露2

主たる特性
周波数 889.6 MHz
タイプ
  • electromagnetic field
Modulation
Modulation type CW
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 値 種別 Method Mass 備考
電力 0.275 W mean 測定値 - at the feeding point
SAR 1.9 mW/g average over mass 測定値 1 g below the skin
SAR 1.93 mW/g average over mass 測定値 1 g 18 mm deep
Additional parameter details

The above values are assumed since not clearly stated in the article.

ばく露3

主たる特性
周波数 889.6 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 15 min
Modulation
Modulation type pulsed
Pulse width 576 µs
Repetition frequency 217 Hz
Additional information

frame length of 4.61 ms
ばく露装置
ばく露の発生源／構造
  • セルラ－電話
  • RF generator
Distance between exposed object and exposure source 25 mm
チャンバの詳細 A mobile phone (power generation and control as in E1) was placed horizontally underneath an acrylic plate (2 mm thick) without any contact. The distance between loudspeaker and plate was 5 mm and between antenna and plate 23 mm.
ばく露装置の詳細 Thin, flat slices of tissue (special absorber foil, slices of sausage, sections of human temporal bone) were placed on the acrylic plate, and thermography was performed with an infrared camera mounted perpendicularly above the mobile phone. In a first step, temperature changes in the mobile phone itself were quantified after the acrylic plate was removed.
Additional information Examinations were performed with continuous as well as pulsed EMF.
パラメータ
測定量 値 種別 Method Mass 備考
電力 2.2 W peak 測定値 - at the feeding point
電力 0.275 W mean 測定値 - at the feeding point

ばく露4

主たる特性
周波数 889.6 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 15 min
Modulation
Modulation type CW
ばく露装置
ばく露の発生源／構造
  • same setup as in E3
Distance between exposed object and exposure source 25 mm
パラメータ
測定量 値 種別 Method Mass 備考
電力 2.2 W peak 測定値 - at the feeding point
Additional parameter details

The power actually applied with CW is not clear. However, since the "more powerful continuous field" is mentioned several times (and 2 W at the end of the discussion), it must be assumed that the same peak power was used in this case as with the pulsed GSM signal.

Reference articles

  • Sievert U et al. (2004): [パルス波およびと連続波の最大周波数（マイクロ波）放射の内耳への生物学的影響]

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:
  • 感覚器
  • eye, ear
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）

In no subject electromagnetic irradiation-induced nystagmus could be recorded. This corresponds to the findings that in the temporal bone very weak caloric effects could only be found in the tissue layers next to the irradiation source, whereas deeper regions seemed unaffected.
These data do not support the theory that mobile phone-induced electromagnetic irradiation may cause caloric negative effects in the human ear.

研究の種別:

研究助成

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