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Effects of extremely low frequency electromagnetic fields on distortion product otoacoustic emissions in rabbits.

Auris, nasus, larynx · 2009 · Mixed · Low evidence

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MixedLow evidencePaper 4985

Twenty rabbits were exposed to 50 Hz electric fields of 5.068 kV/m or 10.182 kV/m for 3 h/day for 14 days. In the 10.182 kV/m group, DPOAE amplitudes increased at 1.5–4.0 kHz on days 6 and 14 (significant at 2.0 and 4.0 kHz), while at 6.0 kHz the day-14 ampli…

Study snapshot

PublicationAuris, nasus, larynx · 2009
Study typeanimal
Reported directionMixed
Evidence ratingLow

Abstract

OBJECTIVE: Humans are continuously exposed to extremely low frequency (ELF), electromagnetic fields (EMF), transmitted from the common sources like power stations, electric transmission lines, communication and radio-television signal transmission units. The present study aimed to assess the effects of 50 Hz ELF-EMF of 5.068 and 10.182 kV/m electric fields, which refer to the lower and upper intensity limits beyond which hazardous effects can be observed, on the auditory functions of rabbits via Distortion Product Otoacoustic Emission (DPOAE) recordings. METHODS: The study was performed on 20 healthy adult female New Zealand White rabbits randomly divided into two groups and applied 50 Hz ELF-EMF with either 5.068 kV/m (Group 1) or 10.182 kV/m (Group 2) of electric field for 3h/day during 14 days. DPOAE responses recorded on the 0th day before exposure (B-EMF) and on the 6th (A-EMF-6th) and 14th (A-EMF-14th) days after exposure (AE). Mean stimulus intensity and emission amplitudes at 1.0-8.0 kHz were analyzed. RESULTS: In Group 2 rabbits, on 6th and 14th days, the DPOAE amplitudes were observed as increased at 1.5-4.0 kHz (at 2.0 and 4.0 kHz significantly) than B-EMF values. At 6.0 kHz, A-EMF-14th amplitudes were significantly lower than A-EMF values. CONCLUSION: These results suggest that ELF EMFs might affect hearing functions by frequency dependent manner. Higher ELF EMFs exposure caused increase of cochlear activity. Ototoxic effect of 10.182 kV/m ELF EMFs may begin at the basal turn of the cochlea by reducing DPOAEs at high frequencies.

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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 typeanimal
Effect directionmixed
PopulationHealthy adult female New Zealand White rabbits
Sample size20
ExposureELF · 5e-05 MHz · 3 h/day for 14 days
Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Twenty rabbits were exposed to 50 Hz electric fields of 5.068 kV/m or 10.182 kV/m for 3 h/day for 14 days. In the 10.182 kV/m group, DPOAE amplitudes increased at 1.5–4.0 kHz on days 6 and 14 (significant at 2.0 and 4.0 kHz), while at 6.0 kHz the day-14 amplitudes were significantly lower than post-exposure values, suggesting frequency-dependent effects.

Outcomes measured

  • Distortion Product Otoacoustic Emissions (DPOAE) amplitudes
  • Auditory/cochlear function (frequency-dependent changes in DPOAE)

Limitations

  • Only rabbits (animal model); applicability to humans not established in abstract
  • Small sample size (20 total)
  • No unexposed/sham control group described in abstract (only two exposure intensities)
  • Short exposure duration (14 days)
  • Outcome limited to DPOAE measures; broader auditory/clinical outcomes not reported
View raw extracted JSON
{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 5e-05,
    "sar_wkg": null,
    "duration": "3 h/day for 14 days"
  },
  "population": "Healthy adult female New Zealand White rabbits",
  "sample_size": 20,
  "outcomes": [
    "Distortion Product Otoacoustic Emissions (DPOAE) amplitudes",
    "Auditory/cochlear function (frequency-dependent changes in DPOAE)"
  ],
  "main_findings": "Twenty rabbits were exposed to 50 Hz electric fields of 5.068 kV/m or 10.182 kV/m for 3 h/day for 14 days. In the 10.182 kV/m group, DPOAE amplitudes increased at 1.5–4.0 kHz on days 6 and 14 (significant at 2.0 and 4.0 kHz), while at 6.0 kHz the day-14 amplitudes were significantly lower than post-exposure values, suggesting frequency-dependent effects.",
  "effect_direction": "mixed",
  "limitations": [
    "Only rabbits (animal model); applicability to humans not established in abstract",
    "Small sample size (20 total)",
    "No unexposed/sham control group described in abstract (only two exposure intensities)",
    "Short exposure duration (14 days)",
    "Outcome limited to DPOAE measures; broader auditory/clinical outcomes not reported"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF-EMF",
    "50 Hz",
    "electric field",
    "kV/m",
    "rabbits",
    "New Zealand White",
    "distortion product otoacoustic emissions",
    "DPOAE",
    "hearing",
    "cochlea"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.2,
      "reason": "Background mentions common ELF sources (power stations/transmission lines), but the experiment is an animal exposure study rather than an occupational cohort."
    }
  ]
}
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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: 10.1016/j.anl.2008.04.011
PubMed: 18606507

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