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

[聴覚及び喉頭前庭に及ぼす携帯電話による電磁界影響] med./bio.

[Effects of Electromagnetic Fields Emitted by Cellular Phone on Auditory and Vestibular Labyrinth].

掲載誌: Laryngorhinootologie 2007; 86 (4): 264-270

この研究は、GSM携帯電話が発する高周波電磁界がヒトのさまざまな機能に与える影響をボランティア実験で調べた。健康な21人の被験者に、携帯電話使用時および非使用時に、頭部のサーモグラフィー測定、ビデオ眼振記録、聴性脳幹誘発反応検査、歪成分耳音響放射記録を行った。その結果、サーモグラフィ測定により、携帯電話使用時に、聴覚および前庭系の刺激につながるような温度上昇は生じないことが示された;携帯電話使用時のビデオ眼振記録は、前庭系の反応の兆候を示さなかった;聴性脳幹誘発反応に携帯電話使用時と非使用時での差は見られなかった;歪成分耳音響放射にも、高周波電磁界ばく露の影響は見られなかった、と報告している。

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研究目的(著者による)

To perform thermographic measurements and to study the biological effects of the radiofrequency irradiation produced by a GSM mobile phone on the inner ear with its sensors of the vestibular and auditory system.

詳細情報

Thermographic investigations were made on various model materials and on the human temporal bone.
Video-nystagmographic recordings of 13 subjects, brainstem electric response audiometry of 24 ears, and recordings of distortion product otoacoustic emissions of 20 ears were performed.

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, CW
ばく露時間: repeated exposure for about 2 or 9 min per ear, depending on the examination, with a 3-min interval between registrations
  • 電力: 2.2 W peak
  • 電力: 255 mW mean
  • SAR: 1.9 mW/g average over mass (1 g) (under the skin)
  • SAR: 1.93 mW/g average over mass (1 g) (at 18 mm depth)
ばく露2: 889.6 MHz
Modulation type: pulsed, CW
ばく露時間: continuous for about 15 min
  • 電力: 2.2 W peak
  • 電力: 255 mW mean
  • SAR: 1.9 mW/g average over mass (1 g) (under the skin)
  • SAR: 1.93 mW/g average over mass (1 g) (at 18 mm depth)

General information

All tests were performed without and with CW and pulsed RF signals in various orders depending on the examination.

ばく露1

主たる特性
周波数 889.6 MHz
タイプ
  • electromagnetic field
ばく露時間 repeated exposure for about 2 or 9 min per ear, depending on the examination, with a 3-min interval between registrations
Modulation
Modulation type pulsed, CW
ばく露装置
ばく露の発生源/構造
  • セルラ-電話
ばく露装置の詳細 The exposure setup for test subjects consisted of two mobile phones that were prepared for external feeding from a signal generator and a broadband power amplifier via a coaxial cable with additional shield surface wave suppression. The mobile phones were attached to adjustable plastic holders mounted on a chair for test subjects. The phone on the examined side was activated by a coaxial relay.
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電力 2.2 W peak 測定値 - -
電力 255 mW mean 測定値 - -
SAR 1.9 mW/g average over mass 測定値 1 g under the skin
SAR 1.93 mW/g average over mass 測定値 1 g at 18 mm depth

ばく露2

主たる特性
周波数 889.6 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for about 15 min
Modulation
Modulation type pulsed, CW
ばく露装置
ばく露の発生源/構造
  • セルラ-電話
ばく露装置の詳細 For the exposure of samples during thermography, a mobile phone was positioned horizontally at a distance of 3 cm parallel to the edge of the wooden worktop of a trolley. Samples were placed in a dish of Piacryl (with walls of 2 mm), the bottom of which was 5 mm apart from the casing and (according to the shape) farther from the antenna of the mobile phone.
Additional information Measurements were made with the mobile phone alone, with a 2-mm absorbing foil, with 2-mm animal tissue (sausage slice), and with pars petrosa of the human temporal bone (dry and wet) cut at about 18 mm depth and positioned with the outer auditory canal above the loudspeaker.
パラメータ
測定量 種別 Method Mass 備考
電力 2.2 W peak 測定値 - -
電力 255 mW mean 測定値 - -
SAR 1.9 mW/g average over mass 測定値 1 g under the skin
SAR 1.93 mW/g average over mass 測定値 1 g at 18 mm depth

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
  • 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)

The thermographic measurements suggest that the mobile phone does not induce any increases of temperature which would lead to a relevant stimulus for the auditory and vestibular system.
The video-nystagmographic recordings do not furnish any indication of vestibular reactions generated by the electromagnetic field. Compared with the recording without the electromagnetic field, the brainstem electric response audiometry under exposure did not reveal any changes. The distortion product otoacoustic emissions do not indicate any possible impacts of the radiofrequency field.
The data show that the electromagnetic fields generated by a mobile phone do not have an effect on the inner ear and auditory system to the colliculus inferior in the brainstem and on the vestibular receptors in the inner ear and the vestibular system.

研究の種別:

研究助成

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