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

[携帯電話関連症状を申告する被験者における携帯電話ばく露後の睡眠] med./bio.

Sleep after mobile phone exposure in subjects with mobile phone-related symptoms.

掲載誌: Bioelectromagnetics 2011; 32 (1): 4-14

この研究は、自己評価による眠気、および睡眠脳波指標に対する無線周波電磁界ばく露(884MHzのGSM信号規格、10g空間平均SARの時間平均値:1.4W/kg)の影響を二重ブラインド法で実験した。被験者電磁界に対する過敏性を訴える人23名、訴えない人25名;全体の平均年齢28歳)には、睡眠前に3時間ばく露(午後7時30分~10時30分、ばく露群と擬似ばく露群)を与え、その後、睡眠検査室で終夜睡眠ポリグラフを記録した。その結果、擬似ばく露群に比べばく露後では、第3および4段階の睡眠徐波睡眠:SWS)が減少し、第2段階睡眠が増加した;ばく露群では第3段階睡眠までの潜時も増加した;脳波のパワースペクトル密度では、第2段階睡眠の最初の30分間における周波数域0.5~1.5および5.75~10.5Hzの活動増加、第2段階睡眠の最初の1時間における周波数域7.5~11.75Hzの活動増加、第2段階睡眠の2時間目の1時間における周波数域4.75~8.25Hzの活動増加が示された;SWSまたは第2段階睡眠の3時間目の1時間においては顕著な変化は見られなかった;事前に調べた電磁界に対する過敏性の訴えはこれらの結果に関連しなかった、と報告している。

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研究目的(著者による)

To study the effects of radiofrequency exposure (GSM) on self-evaluated sleepiness and objective EEG measures during sleep in a non-sensitive and a sensitive group (with symptoms in relation to mobile phone use).

詳細情報

48 subjects (mean age 28 years; 27 females, 21 males) were exposed for 3 h (19:30-22:30; active or sham exposure) prior to sleep. The test sessions were separated by at least one week. The mobile phone sensitive group consisted of 23 subjects with GSM mobile phone-related symptoms (15 females) and the non-sensitive group, without such symptoms, consisted of 25 subjects (12 females).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 884 MHz
Modulation type: AM, pulsed
ばく露時間: continuous for 3 hr
  • SAR: 1.4 W/kg average over time (10 g)
  • SAR: 1.95 W/kg peak (10 g) (during non-GSM-DTX mode)
  • SAR: 1.8 W/kg peak (1 g) (gray matter)
  • SAR: 0.2 W/kg spatial average (1 g) (gray matter)
  • SAR: 0.18 W/kg spatial average (1 g) (thalamus)

ばく露1

主たる特性
周波数 884 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 3 hr
Modulation
Modulation type AM, pulsed
Pulse width 0.577 ms
Additional information

amplitude modulation frequencies: 2, 8, 217 and 1736 Hz 11 s non-GSM-DTX mode, 5 s GSM-DTX mode

ばく露装置
ばく露の発生源/構造
  • micropatch antenna
ばく露装置の詳細 low-weight, stacked, micropatch antenna fixed on a headset, balanced by a counterweight, antenna placed on the left side of the head and a small ceramic plate which was heated to 39° C +/- 0.2° C was fixed to the left ear lobe (to mimic the sensation from a warm phone); test persons placed in a room with RF absorbers on three sides
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
SAR 1.4 W/kg average over time - 10 g -
SAR 1.95 W/kg peak - 10 g during non-GSM-DTX mode
SAR 1.8 W/kg peak - 1 g gray matter
SAR 0.2 W/kg spatial average - 1 g gray matter
SAR 0.18 W/kg spatial average - 1 g thalamus

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:
  • ばく露後

研究の主なアウトカム(著者による)

The data showed that following exposure, time in sleep stages 3 and 4 (so-called "slow-wave sleep", deep sleep phase) decreased by 9.5 minutes (12% out of a total of 78.6 minutes), and time in sleep stage 2 increased by 8.3 minutes (4% out of a total of 196.3 minutes) compared to sham exposure. The latency to sleep stage 3 was also prolonged by 4.8 min after exposure.
Power density spectral analysis of the EEG indicated an enhanced activation in the frequency ranges 0.5-1.5 and 5.75-10.5 Hz (representing parts of delta wave, theta wave and alpha wave frequency bands) during the first 30 min of sleep stage 2. During the full first hour of sleep stage 2 the spectral density increased particularly within the frequency range of 7.5-11.75 Hz. During the second hour of the sleep stage 2 activity was elevated within the frequency range 4.75-8.25 Hz. No pronounced power changes were observed in slow-wave sleep (sleep stages 3+4) or for the third hour of sleep stage 2.
No differences were found between non-sensitive controls and sensitive subjects with prior complaints of mobile phone-related symptoms.
The data confirm previous findings (see "realted articles") that radiofrequency exposure increased the spectral density of the alpha wave range in the sleep EEG, and indicated moderate impairment of slow-wave sleep. Furthermore, reported differences in sensitivity to mobile phone use were not reflected in sleep parameters.

研究の種別:

研究助成

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