Effect of 7, 14 and 21 Hz modulated 450 MHz microwave radiation on human electroencephalographic rhythms.

International journal of radiation biology · 2008 · Mixed · Low evidence

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MixedLow evidencePaper 6482

Study snapshot

PublicationInternational journal of radiation biology · 2008

Study typeother

Reported directionMixed

Evidence ratingLow

Abstract

PURPOSE: The aim of this study was to evaluate the effect of microwaves modulated at different frequencies on human electroencephalographic (EEG) rhythms. MATERIALS AND METHODS: Thirteen healthy volunteers were exposed to microwaves (450 MHz) pulse-modulated at frequencies of 7, 14 and 21 Hz. The field power density at the scalp was 0.16 mW/cm2. Our experimental protocol consisted of two five-cycle (1 min on and 1 min off) series of exposures at fixed modulation frequencies. A relative change in the EEG power with and without exposure was used as a quantitative measure. EEG frequencies recorded in the theta (4-6.8 Hz), alpha (8-13 Hz), betal (15-20 Hz), and beta2 (22-38 Hz) bands were analyzed. RESULTS: Modulated microwaves caused an increase in the average EEG alpha (17%) and beta (7%) power but the theta rhythm remained unaffected. Increases in the EEG alpha and beta power were statistically significant during the first half-period of the exposure interval (30 s) at the modulation frequencies of 14 and 21 Hz. Differences were found in individual sensitivity to exposure. Increases in the EEG beta power appeared statistically significant in the case of four subjects. CONCLUSIONS: Our findings suggest that the effect of the 450 MHz microwave radiation modulated at 7, 14 and 21 Hz varies depending on the modulation frequency. The microwave exposure modulated at 14 and 21 Hz enhanced the EEG power in the alpha and beta frequency bands, whereas no enhancement occurred during exposure to the modulation frequency of 7 Hz.

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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 typeother

Effect directionmixed

Population13 healthy volunteers

Sample size13

ExposureRF · 450 MHz · Two five-cycle series (1 min on/1 min off); effects noted during first 30 s of exposure intervals

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Exposure to 450 MHz pulse-modulated microwaves increased average EEG alpha power (17%) and beta power (7%), while theta rhythm was unaffected. Statistically significant increases in alpha and beta power occurred during the first 30 s of exposure at modulation frequencies of 14 and 21 Hz; no enhancement was reported at 7 Hz modulation. Individual sensitivity varied, with statistically significant beta increases reported in four subjects.

Outcomes measured

EEG power (theta 4–6.8 Hz, alpha 8–13 Hz, beta1 15–20 Hz, beta2 22–38 Hz)

Limitations

Small sample size (n=13)
Individual sensitivity differences noted; statistically significant beta increases reported only in a subset (four subjects)
Exposure source and SAR not reported in abstract

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": "RF",
    "source": null,
    "frequency_mhz": 450,
    "sar_wkg": null,
    "duration": "Two five-cycle series (1 min on/1 min off); effects noted during first 30 s of exposure intervals"
  },
  "population": "13 healthy volunteers",
  "sample_size": 13,
  "outcomes": [
    "EEG power (theta 4–6.8 Hz, alpha 8–13 Hz, beta1 15–20 Hz, beta2 22–38 Hz)"
  ],
  "main_findings": "Exposure to 450 MHz pulse-modulated microwaves increased average EEG alpha power (17%) and beta power (7%), while theta rhythm was unaffected. Statistically significant increases in alpha and beta power occurred during the first 30 s of exposure at modulation frequencies of 14 and 21 Hz; no enhancement was reported at 7 Hz modulation. Individual sensitivity varied, with statistically significant beta increases reported in four subjects.",
  "effect_direction": "mixed",
  "limitations": [
    "Small sample size (n=13)",
    "Individual sensitivity differences noted; statistically significant beta increases reported only in a subset (four subjects)",
    "Exposure source and SAR not reported in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "450 MHz",
    "microwave radiation",
    "RF",
    "pulse-modulated",
    "7 Hz",
    "14 Hz",
    "21 Hz",
    "EEG",
    "alpha power",
    "beta power",
    "theta rhythm",
    "human volunteers"
  ],
  "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: 10.1080/09553000701691679
PubMed: 18058332

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