Effects of Mobile Electromagnetic Exposure on Brain Oscillations and Cortical Excitability: Scoping Review

Abstract

Category: Neuroscience Tags: electromagnetic fields, mobile phone exposure, brain oscillations, cortical excitability, EEG, 5G, radiofrequency safety DOI: 10.3390/s25092749 URL: mdpi.com Overview With the widespread adoption of smartphones, concerns about increased exposure to non-ionizing radiofrequency have emerged. This scoping review examines the effects of mobile phone exposure on neural oscillations and cortical excitability, focusing on both motor and non-motor regions of the cerebral cortex. A comprehensive review identified seventy-eight studies involving healthy individuals that utilized electroencephalography (EEG), and only two studies investigated transcranial magnetic stimulation (TMS) as primary technical tools. Findings - Mobile phone exposure may affect brain oscillations and cortical excitability. - The review finds that mobile electromagnetic (EM) exposure can induce changes in brain oscillations, primarily increasing the amplitude of alpha, beta, theta, and delta bands (especially in the eyes closed condition). - Mobile EM exposure may enhance cortical silent period (CSE) due to strengthened facilitator mechanisms and weakened inhibitory mechanisms. - There are significant inconsistencies in experimental methods across studies, limiting definitive conclusions. - Research on fifth-generation (5G) technology, especially mmWave exposure from next-gen networks, is limited and requires urgent exploration. Conclusions - Findings support the connection between EMF exposure and measurable changes in neural activity, underlining the need to revise current safety guidelines such as SAR limits, and to utilize neurophysiological EEG and TMS metrics in exposure assessments. - 5G technology’s use of higher frequency mmWave bands (>24 GHz) could present unique tissue and neural interaction risks, highlighting the necessity for precautionary actions until robust evidence is gathered. - Recommendations include: more research on 5G effects, study designs that account for age and gender differences, refinement of methodologies, and standardization of exposure/control conditions and technical parameters in experimental studies. There is a clear call to enhance the quality of future research and to address the health risks associated with EMF exposure.

AI evidence extraction

Main findings

This scoping review of 78 EEG studies and 2 TMS-focused studies in healthy individuals reports that mobile phone electromagnetic exposure may induce measurable changes in brain oscillations, described primarily as increased amplitude in alpha, beta, theta, and delta bands (notably with eyes closed). It also reports that exposure may enhance cortical silent period, while emphasizing substantial methodological inconsistencies that limit definitive conclusions and noting limited evidence on 5G/mmWave exposures.

Outcomes measured

• Brain oscillations (EEG)
• Cortical excitability (TMS measures)
• Alpha/beta/theta/delta band amplitude
• Cortical silent period (CSE)

Limitations

• Significant inconsistencies in experimental methods across included studies
• Limited number of studies using TMS as the primary tool (two studies)
• Limited research on 5G technology and mmWave exposure (>24 GHz)

Suggested hubs

• who-icnirp (0.62)
  Discusses implications for revising safety guidelines such as SAR limits.
• 5g-policy (0.58)
  Highlights limited evidence on 5G/mmWave exposure and calls for precautionary actions.

{
    "study_type": "review",
    "exposure": {
        "band": "RF",
        "source": "mobile phone",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Healthy individuals",
    "sample_size": null,
    "outcomes": [
        "Brain oscillations (EEG)",
        "Cortical excitability (TMS measures)",
        "Alpha/beta/theta/delta band amplitude",
        "Cortical silent period (CSE)"
    ],
    "main_findings": "This scoping review of 78 EEG studies and 2 TMS-focused studies in healthy individuals reports that mobile phone electromagnetic exposure may induce measurable changes in brain oscillations, described primarily as increased amplitude in alpha, beta, theta, and delta bands (notably with eyes closed). It also reports that exposure may enhance cortical silent period, while emphasizing substantial methodological inconsistencies that limit definitive conclusions and noting limited evidence on 5G/mmWave exposures.",
    "effect_direction": "mixed",
    "limitations": [
        "Significant inconsistencies in experimental methods across included studies",
        "Limited number of studies using TMS as the primary tool (two studies)",
        "Limited research on 5G technology and mmWave exposure (>24 GHz)"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "electromagnetic fields",
        "mobile phone exposure",
        "brain oscillations",
        "cortical excitability",
        "EEG",
        "TMS",
        "5G",
        "mmWave",
        "radiofrequency safety",
        "SAR limits"
    ],
    "suggested_hubs": [
        {
            "slug": "who-icnirp",
            "weight": 0.61999999999999999555910790149937383830547332763671875,
            "reason": "Discusses implications for revising safety guidelines such as SAR limits."
        },
        {
            "slug": "5g-policy",
            "weight": 0.57999999999999996003197111349436454474925994873046875,
            "reason": "Highlights limited evidence on 5G/mmWave exposure and calls for precautionary actions."
        }
    ]
}

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