Stimulation of the brain with radiofrequency electromagnetic field pulses affects sleep-dependent performance improvement.

Brain stimulation · 2013 · Mixed · Low evidence

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MixedLow evidencePaper 4619

Study snapshot

PublicationBrain stimulation · 2013

Study typerandomized_trial

Reported directionMixed

Evidence ratingLow

Abstract

BACKGROUND: Sleep-dependent performance improvements seem to be closely related to sleep spindles (12-15 Hz) and sleep slow-wave activity (SWA, 0.75-4.5 Hz). Pulse-modulated radiofrequency electromagnetic fields (RF EMF, carrier frequency 900 MHz) are capable to modulate these electroencephalographic (EEG) characteristics of sleep. OBJECTIVE: The aim of our study was to explore possible mechanisms how RF EMF affect cortical activity during sleep and to test whether such effects on cortical activity during sleep interact with sleep-dependent performance changes. METHODS: Sixteen male subjects underwent 2 experimental nights, one of them with all-night 0.25-0.8 Hz pulsed RF EMF exposure. All-night EEG was recorded. To investigate RF EMF induced changes in overnight performance improvement, subjects were trained for both nights on a motor task in the evening and the morning. RESULTS: We obtained good sleep quality in all subjects under both conditions (mean sleep efficiency > 90%). After pulsed RF EMF we found increased SWA during exposure to pulse-modulated RF EMF compared to sham exposure (P < 0.05) toward the end of the sleep period. Spindle activity was not affected. Moreover, subjects showed an increased RF EMF burst-related response in the SWA range, indicated by an increase in event-related EEG spectral power and phase changes in the SWA range. Notably, during exposure, sleep-dependent performance improvement in the motor sequence task was reduced compared to the sham condition (-20.1%, P = 0.03). CONCLUSION: The changes in the time course of SWA during the exposure night may reflect an interaction of RF EMF with the renormalization of cortical excitability during sleep, with a negative impact on sleep-dependent performance improvement.

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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 typerandomized_trial

Effect directionmixed

PopulationSixteen male subjects

Sample size16

ExposureRF · 900 MHz · all-night exposure; 0.25–0.8 Hz pulsed (pulse-modulated) RF EMF

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Sleep quality was good under both exposure and sham conditions (mean sleep efficiency >90%). Pulsed RF EMF exposure (900 MHz carrier; 0.25–0.8 Hz pulsed) increased SWA toward the end of the sleep period compared with sham (P<0.05), while spindle activity was not affected. Sleep-dependent performance improvement on the motor sequence task was reduced during the exposure condition versus sham (-20.1%, P=0.03).

Outcomes measured

Sleep slow-wave activity (SWA; 0.75–4.5 Hz)
Sleep spindle activity (12–15 Hz)
Event-related EEG spectral power and phase changes in SWA range
Sleep-dependent performance improvement on a motor sequence task
Sleep quality (sleep efficiency)

Limitations

Small sample size (n=16)
Only male subjects

View raw extracted JSON

{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "RF",
    "source": null,
    "frequency_mhz": 900,
    "sar_wkg": null,
    "duration": "all-night exposure; 0.25–0.8 Hz pulsed (pulse-modulated) RF EMF"
  },
  "population": "Sixteen male subjects",
  "sample_size": 16,
  "outcomes": [
    "Sleep slow-wave activity (SWA; 0.75–4.5 Hz)",
    "Sleep spindle activity (12–15 Hz)",
    "Event-related EEG spectral power and phase changes in SWA range",
    "Sleep-dependent performance improvement on a motor sequence task",
    "Sleep quality (sleep efficiency)"
  ],
  "main_findings": "Sleep quality was good under both exposure and sham conditions (mean sleep efficiency >90%). Pulsed RF EMF exposure (900 MHz carrier; 0.25–0.8 Hz pulsed) increased SWA toward the end of the sleep period compared with sham (P<0.05), while spindle activity was not affected. Sleep-dependent performance improvement on the motor sequence task was reduced during the exposure condition versus sham (-20.1%, P=0.03).",
  "effect_direction": "mixed",
  "limitations": [
    "Small sample size (n=16)",
    "Only male subjects"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency electromagnetic fields",
    "RF EMF",
    "900 MHz",
    "pulse-modulated",
    "sleep",
    "EEG",
    "slow-wave activity",
    "sleep spindles",
    "motor sequence task",
    "sleep-dependent performance"
  ],
  "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: 10.1016/j.brs.2013.01.017
PubMed: 23482083

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