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

[主観的な電磁過敏症被検者と一般人の対照群による単一経頭蓋磁気刺激の認知比較] med./bio.

Comparison perception of singular transcranial magnetic stimuli by subjectively electrosensitive subjects and general population controls.

掲載誌: Bioelectromagnetics 2005; 26 (4): 287-298

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研究目的(著者による)

The aim of the study was to investigate the ability of the subjects to differentiate between real magnetic stimulation and a sham exposure.

詳細情報

Transcranial magnetic stimulation of the dorsolateral prefrontal cortex was used to measure thresholds of individual perception and motor response in three groups of subjects: 1) subjectively electrosensitive people, 2) general population controls with a high burden of complaints related to electromagnetic field exposure, and 3) general population controls with a low burden of complaints.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1:
  • unspecified
Modulation type: single pulse
ばく露時間: repeated exposure
ばく露2:
  • unspecified
Modulation type: single pulse
ばく露時間: repeated exposure
-

General information

Perception thresholds under double blind conditions as well as objectively measured motor thresholds for evoked potentials were determined by applying singular transcranial magnetic pulses to the motor cortex.

ばく露1

主たる特性
周波数
  • unspecified
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 repeated exposure
Modulation
Modulation type single pulse
Additional information

four series of 19 consecutive single pulses with increasing amplitudes

ばく露装置
ばく露の発生源/構造
  • コイル
  • figure-8, Magstim Rapid Pro stimulator
ばく露装置の詳細 Perception thresholds were determined by stimulating subjects with a figure-8 coil (double circular 70-mm coil) placed over the left dorsolateral prefrontal cortex (DLPFC), as usually done in rTMS studies treating depressive patients [Eichhammer et al., 2002], but using singular stimuli.
Sham exposure A sham exposure was conducted.
Additional information A specific sham coil was used imitating the characteristic acoustic click associated with an active stimulation but not inducing a magnetic field. Active and sham coils were handed out according to a randomization scheme for the four series (ABAB versus BABA) so that both the subjects and the physicians applying the coils remained blinded.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.05 T minimum - - -
磁束密度 1.05 T maximum - - -

ばく露2

主たる特性
周波数
  • unspecified
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 repeated exposure
Modulation
Modulation type single pulse
Additional information

up to 10 consecutive single pulses for each amplitude

ばく露装置
ばく露の発生源/構造
  • コイル
  • figure-8, two Magstim 200 stimulators connected via a Bistim module
チャンバの詳細 Resting (RMT) and active (AMT) motor thresholds, representing paradigms of cortical excitability, were measured by TMS according to [Rossini et al., 1994].
ばく露装置の詳細 The coil was held with the junction of the two wings tangential to the skull and the handle pointing backwards and 45° away from the midline. Thus, the induced current in the brain was directed about perpendicular to the assumed line of the central sulcus.
Additional information Motor evoked potentials (MEP) from the right abductor digiti minimi muscle were recorded using surface electrodes in a belly-tendon montage. MEP amplitudes were measured peak to peak in 10 consecutive trials for each stimulus intensity.
パラメータ

No parameters are specified for this exposure.

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:
調査の時期:
  • ばく露中

研究の主なアウトカム(著者による)

There were no significant differences between groups in the thresholds, neither of detecting the real magnetic stimulus nor in motor response. But the three groups differed significantly in differentiating between stimulation and sham condition. The subjectively electrosensitive people have the lowest ability to differentiate and the control group with high level of electromagnetic field-related complaints has the best ability to differentiate. Differences between groups were mostly due to false alarm reactions in the sham condition reported by subjectively electrosensitives.
The authors found no objective correlation of the self perception of being "electrosensitive." Overall, the experiment does not support the hypothesis that subjectively electrosensitive patients suffer from a physiological hypersensitivity to electromagnetic fields or stimuli.

研究の種別:

研究助成

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