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

[携帯電話からの放射の認知への影響:ばく露を受ける体側およびばく露時間の影響] med./bio.

Cognitive effects of radiation emitted by cellular phones: the influence of exposure side and time

掲載誌: Bioelectromagnetics 2009; 30 (3): 198-204

この研究は、標準GSM携帯電話からの無線周波電磁放射(RFR)へのばく露がヒトの認知機能に及ぼす時間依存性の影響を調べた。48人の健康な右利きの男性被験者は、頭の両側に置かれた2つのGSM電話の1つからのばく露を受けている間、空間作業記憶タスク(左手または右手応答のいずれかが必要)を遂行した。被験者は無作為に3つのグループに分けられた。それぞれのグループは、頭の左側か右側へのばく露または擬似ばく露の3つのばく露条件のいずれかに割り当てられた。実験は50試行/ブロックで12ブロックから成った。応答時間(RT)と応答の正確度が記録された。その結果、最初の2つのブロックにおいて、左側ばく露条件下での右手応答の平均RTは、右側および擬似ばく露グループを合わせて平均したRTに比べ、有意に長いことが示された;これらの知見は、RTへのばく露の影響が存在すること、およびばく露時間が、応答に用いる手およびばく露の側と共に、タスク遂行成績に検出可能なRFRの影響を生じさせる上で重要な役割を果たす可能性があることが示された、と報告している。

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研究目的(著者による)

To examine time dependence effects of exposure to radiofrequency irradiation, emitted by GSM cellular phones, on cognitive functions of humans. The authors aimed to replicate and extend a previous study (publication 12887); especially to examine time-dependency and slowing of the left-hand response as results of the previous study.

詳細情報

48 healthy males (right-handed) were divided into three groups: 1) exposure to the left side of the head, 2) exposure to the right side of the head, 3) sham exposure. All partcipants performed a spatial working memory task (that required either a left-hand or a right-hand response; 12 blocks of 50 trials). By averaging the reaction times separately for each block, the time course of the radiofrequency irradiation effect could be assessed.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 890.2 MHz
Modulation type: pulsed
ばく露時間: 1 h
  • 電力: 2 W peak
  • 電力: 0.25 W average over time
  • SAR: 0.54 W/kg minimum (unspecified)
  • SAR: 1.09 W/kg maximum (unspecified)

General information

three exposure conditions were tested: i) exposure at the left side of the head ii) exposure at the right side of the head iii) sham exposure

ばく露1

主たる特性
周波数 890.2 MHz
タイプ
  • electromagnetic field
ばく露時間 1 h
Modulation
Modulation type pulsed
Pulse width 0.577 ms
Duty cycle 12.5 %
Repetition frequency 217 Hz
ばく露装置
ばく露の発生源/構造
  • セルラ-電話
Distance between exposed object and exposure source 1.5 cm
ばく露装置の詳細 two standard Nokia 5110 GSM cellular phones attached to both sides of the head by a nonconductive frame
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電力 2 W peak - - -
電力 0.25 W average over time - - -
SAR 0.54 W/kg minimum - unspecified -
SAR 1.09 W/kg maximum - unspecified -

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)

During the first two time blocks, the average reaction time of the right-hand responses [matching condition] was significantly longer under left-side exposure than under right-side exposure and sham exposure averaged together. This result confirms an effect of exposure on reaction times. Left-hand responses [mismatching condition] showed the same pattern, but it was non-significant. The participants failed to judge which phone was operating during the experiment.
Although the present results confirmed some findings from the previous study (e.g. time dependency of reaction times), differences between the present results and previous findings may be due to the following factors: exposure duration, responding hand, side of exposure, and differences in the cognitive tasks. These factors may have major influence on the detection of radiofrequency irradiation effects.

研究の種別:

研究助成

Replicated studies

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