RF Safe

Effects of GSM 900 MHz on middle cerebral artery blood flow assessed by transcranial Doppler sonography.

Radiation research · 2012 · No effect · Moderate evidence

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No effectModerate evidencePaper 4495

In a double-blind cross-over study comparing sham vs real GSM 900 MHz mobile phone exposure for 20 minutes, no significant changes were detected in middle cerebral artery blood flow velocity, pulsatility index, or resistance index before, during, or after exp…

Study snapshot

PublicationRadiation research · 2012
Study typerandomized_trial
Reported directionNo effect
Evidence ratingModerate

Abstract

Mobile phone use has increased worldwide but its possible effects on the brain remain unclear. The aim of the present study was to investigate the effect of acute exposure to a radio frequency electromagnetic field (RF EMF) generated by a mobile phone operating in the Global System for Mobile Communication (GSM) 900 MHz on cerebral blood flow. Twenty-nine volunteers attended two experimental sessions: a sham exposure session and a real exposure session in a cross-over double-blind study in which a mobile phone was positioned on the left side of the head. In one session, the mobile phone was operated without RF radiation (sham phone) and in the other study it was operated with RF radiation (real phone) for 20 min. Thus, each subject served as its own control. Middle cerebral artery blood flow was monitored noninvasively by transcranial Doppler sonography to measure middle cerebral artery blood flow velocity. Pulsatility index and resistance index were also evaluated. A voluntary breath holding physiological test was carried out as a positive control for testing cerebral vasoreactivity. Hemodynamic variables were recorded and analyzed before, during and after mobile phone exposure. No significant changes were detected in studied variables in middle cerebral arteries during sham or real exposure. In the exposed side the cerebral blood flow velocity, the pulsatility index and the resistance index during sham and real exposure were respectively: [61.9 ± 1.3, 61.7 ± 1.3 cm/s (P = 0.89)]; [0.93 ± 0.03, 0.90 ± 0.02 (P = 0.84)] and [0.58 ± 0.01, 0.58 ± 0.01 (P = 0.96)] at baseline; and [60.6 ± 1.3, 62 ± 1.6 cm/s (P = 0.40)]; [0.91 ± 0.03, 0.87 ± 0.03 (P = 0.97)]; [0.57 ± 0.01, 0.56 ± 0.01 (P = 0.82)] after 20 min of exposure. Twenty minutes of RF exposure to a mobile phone does not seem to affect the cerebral circulation.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typerandomized_trial
Effect directionno_effect
Population29 volunteers
Sample size29
ExposureRF · 900 MHz · 20 min (acute exposure)
Evidence strengthModerateConfidence: 78% · Peer reviewed: yes

Main findings

In a double-blind cross-over study comparing sham vs real GSM 900 MHz mobile phone exposure for 20 minutes, no significant changes were detected in middle cerebral artery blood flow velocity, pulsatility index, or resistance index before, during, or after exposure.

Outcomes measured

  • Middle cerebral artery blood flow velocity (transcranial Doppler sonography)
  • Pulsatility index
  • Resistance index
  • Cerebral vasoreactivity (breath holding test as positive control)

Limitations

  • Acute exposure only (20 minutes)
  • Small sample size (n=29)
  • Exposure metrics such as SAR not reported in abstract
View raw extracted JSON
{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 900,
    "sar_wkg": null,
    "duration": "20 min (acute exposure)"
  },
  "population": "29 volunteers",
  "sample_size": 29,
  "outcomes": [
    "Middle cerebral artery blood flow velocity (transcranial Doppler sonography)",
    "Pulsatility index",
    "Resistance index",
    "Cerebral vasoreactivity (breath holding test as positive control)"
  ],
  "main_findings": "In a double-blind cross-over study comparing sham vs real GSM 900 MHz mobile phone exposure for 20 minutes, no significant changes were detected in middle cerebral artery blood flow velocity, pulsatility index, or resistance index before, during, or after exposure.",
  "effect_direction": "no_effect",
  "limitations": [
    "Acute exposure only (20 minutes)",
    "Small sample size (n=29)",
    "Exposure metrics such as SAR not reported in abstract"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "GSM 900 MHz",
    "mobile phone",
    "RF EMF",
    "cerebral blood flow",
    "middle cerebral artery",
    "transcranial Doppler sonography",
    "double-blind",
    "cross-over",
    "sham exposure"
  ],
  "suggested_hubs": []
}
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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1667/rr3007.1
PubMed: 23106209

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