Project NEMESIS: perception of a 50 Hz electric and magnetic field at low intensities (laboratory experiment).

Bioelectromagnetics · 2002 · Mixed · Low evidence

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MixedLow evidencePaper 5311

Study snapshot

PublicationBioelectromagnetics · 2002

Study typerandomized_trial

Reported directionMixed

Evidence ratingLow

Abstract

The Electrical Hypersensitivity Syndrome (EHS) is a condition where people suffer from various nonspecific health symptoms attributed to an assumed adverse effect of electric and magnetic fields (EMF). Many EHS patients report the ability to consciously perceive EMF at very low intensities. The existence of a direct EMF perception could be the key to explain at least partially the aetiology of EHS through stress mechanisms and allow the comparison with well known environmental stressors such as noise or odor. The double blind laboratory experiment tested the hypothesis that there are subjects with the ability to perceive 50 Hz EMF at 100 V/m and 6 microT (EMF sensitive) and to investigate the prevalence of EMF sensitivity in a group consisting of subjects with or without self-reported EHS. A total of 63 volunteers, 49 with EHS and 14 controls, took part in the EMF perception experiment, where 10 sham and 10 exposed 2 min blocks had to be judged in randomized sequence (field on/field off). Seven out of 63 subjects reached a statistically significant result which points to the existence of a small EMF sensitive subgroup within the study group. There was no relevant difference between the subjects with self reported EHS and those without in terms of the success rate in the field perception experiment, as well as the number and types of symptoms encountered during the test. The results of the EMF perception experiment suggest that EHS is not a prerequisite for the ability to consciously perceive weak EMF and vice versa.

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 directionmixed

PopulationVolunteers with or without self-reported electrical hypersensitivity syndrome (EHS)

Sample size63

ExposureELF · 0.05 MHz · 20 blocks of 2 min (10 sham, 10 exposed)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In a double-blind laboratory perception task (100 V/m electric field; 6 microT magnetic field), 7/63 subjects achieved statistically significant performance suggesting a small EMF-sensitive subgroup. There was no relevant difference between self-reported EHS participants and controls in perception success rate or in the number and types of symptoms during the test. The authors conclude that self-reported EHS was not a prerequisite for perceiving weak EMF, and perceiving weak EMF was not a prerequisite for reporting EHS.

Outcomes measured

Ability to consciously perceive 50 Hz electric and magnetic fields (field on/field off judgments)
Prevalence of EMF sensitivity (statistically significant perception performance)
Symptoms encountered during the test (number and types)

Limitations

Small control group (14 controls vs 49 with self-reported EHS)
Outcome is based on statistical significance in repeated judgments; details on correction for multiple testing are not provided in the abstract
Laboratory exposure limited to 50 Hz at 100 V/m and 6 microT with short 2-minute blocks; may not generalize to other exposures or real-world settings

View raw extracted JSON

{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": "20 blocks of 2 min (10 sham, 10 exposed)"
  },
  "population": "Volunteers with or without self-reported electrical hypersensitivity syndrome (EHS)",
  "sample_size": 63,
  "outcomes": [
    "Ability to consciously perceive 50 Hz electric and magnetic fields (field on/field off judgments)",
    "Prevalence of EMF sensitivity (statistically significant perception performance)",
    "Symptoms encountered during the test (number and types)"
  ],
  "main_findings": "In a double-blind laboratory perception task (100 V/m electric field; 6 microT magnetic field), 7/63 subjects achieved statistically significant performance suggesting a small EMF-sensitive subgroup. There was no relevant difference between self-reported EHS participants and controls in perception success rate or in the number and types of symptoms during the test. The authors conclude that self-reported EHS was not a prerequisite for perceiving weak EMF, and perceiving weak EMF was not a prerequisite for reporting EHS.",
  "effect_direction": "mixed",
  "limitations": [
    "Small control group (14 controls vs 49 with self-reported EHS)",
    "Outcome is based on statistical significance in repeated judgments; details on correction for multiple testing are not provided in the abstract",
    "Laboratory exposure limited to 50 Hz at 100 V/m and 6 microT with short 2-minute blocks; may not generalize to other exposures or real-world settings"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "electrical hypersensitivity syndrome",
    "EHS",
    "EMF perception",
    "double blind",
    "50 Hz",
    "electric field",
    "magnetic field",
    "100 V/m",
    "6 microT",
    "sham exposure",
    "laboratory experiment"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.25,
      "reason": "Study concerns EHS and perception of low-intensity 50 Hz EMF, a topic often addressed in major EMF health guidance discussions."
    }
  ]
}

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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: 10.1002/bem.95
PubMed: 11793403

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