A mathematical model and experimental procedure to analyze the cognitive effects of audio frequency magnetic fields

2023 · Harm · Low evidence

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HarmLow evidencePaper 468

Study snapshot

Publicationmanual · 2023

Study typerandomized_trial

Reported directionHarm

Evidence ratingLow

Abstract

A mathematical model and experimental procedure to analyze the cognitive effects of audio frequency magnetic fields Navarro EA, Navarro-Modesto E. A mathematical model and experimental procedure to analyze the cognitive effects of audio frequency magnetic fields. Front Hum Neurosci. 2023 May 12;17:1135511. doi: 10.3389/fnhum.2023.1135511. Abstract Audio frequency magnetic fields (20 Hz-20 kHz) are magnetic fields in extremely low frequency-very low frequency (ELF-VLF) bands that are present near audio equipment and acoustic transducers. These devices transform and operate the electrical signal from the recordings or other devices into acoustic and audio signals. The cognitive influence of sound and noise has been widely studied and recognized since the times of ancient Rome; however, the cognitive effects of the magnetic fields of these frequencies have not been studied. Due to the extensive use of audio devices that use this type of transducer near the temporal-parietal area, we believe that it is of interest to study their impact on short-term memory or working memory (WM) and to analyze their potential as they operate as a transcranial magnetic stimulation. In this study, a mathematical model and an experimental tool are introduced to analyze memory performance. The model dissociates the reaction time of a cognitive task. We analyze the model in data from a group of 65 young, healthy subjects. WM is assessed in our experimental setup by means of the Sternberg test (ST), whereby during the ST, one subgroup was exposed to an audio frequency magnetic stimulus, and the other subgroup received a sham stimulus. The magnetic stimulus was ~0.1 μT and was applied to both sides of the head at the frontal cortex near the temporal-parietal area, which is where WM is expected to be located. The ST records reaction times when determining whether an object displayed on the computer screen is one of the objects to be remembered. The results are analyzed within the mathematical model and changes are observed, including the deterioration of WM, which could affect 32% of its operability. Conclusion In this article, we have presented a mathematical model and an experimental procedure to study cognitive effects on WM. The model distinguishes between the effects on peripheral activity and cognitive activity in the brain. This model is simple and applicable to the non-invasive study of cognitive impairment under the action of stimuli of different origins. This procedure has been applied to the study of the effects of audio frequency magnetic stimulus on the area of the brain that supports WM. The procedure has been applied to a homogeneous set of 65 young, healthy subjects, i.e., undergraduate students. Tests performed with exposed and non-exposed groups have been analyzed and show statistically significant differences in response times that can be separated according to the mathematical model. The differences show a small reduction in the time spent in response selection, preparation, and execution of 15 ms over 428 ms (1.5%), the effect of which could resemble the activation of an alert situation. However, exposure results in 32% longer delays in memory search than in the case of non-exposure. These results indicate that exposure to magnetic fields in the audio frequency band could produce significant cognitive impairment in the young population. Finally, we believe that eddy currents play a plausible role in the biophysical mechanism of action that could be related to some physical stimulus or tissue micro heating. Open access paper: ncbi.nlm.nih.gov

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 directionharm

PopulationYoung, healthy undergraduate students

Sample size65

ExposureELF-VLF (audio frequency)

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

In a Sternberg test, the exposed subgroup (~0.1 µT audio-frequency magnetic stimulus applied bilaterally near the temporal-parietal area) showed statistically significant reaction-time differences versus sham. The authors report a small reduction (~15 ms over 428 ms; 1.5%) in response selection/preparation/execution time, but a 32% longer delay in memory search compared with non-exposure, interpreted as deterioration of working memory.

Outcomes measured

Working memory (WM) performance
Reaction time components during Sternberg test (memory search; response selection/preparation/execution)

Limitations

Exposure frequency/frequencies and exposure duration not specified in the abstract
Randomization/blinding procedures not described in the abstract
Outcome reporting relies on modeled decomposition of reaction time; details not provided in the abstract
Single population of young, healthy undergraduate students; generalizability may be limited

View raw extracted JSON

{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "ELF-VLF (audio frequency)",
    "source": "audio equipment/acoustic transducers (audio frequency magnetic stimulus)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Young, healthy undergraduate students",
  "sample_size": 65,
  "outcomes": [
    "Working memory (WM) performance",
    "Reaction time components during Sternberg test (memory search; response selection/preparation/execution)"
  ],
  "main_findings": "In a Sternberg test, the exposed subgroup (~0.1 µT audio-frequency magnetic stimulus applied bilaterally near the temporal-parietal area) showed statistically significant reaction-time differences versus sham. The authors report a small reduction (~15 ms over 428 ms; 1.5%) in response selection/preparation/execution time, but a 32% longer delay in memory search compared with non-exposure, interpreted as deterioration of working memory.",
  "effect_direction": "harm",
  "limitations": [
    "Exposure frequency/frequencies and exposure duration not specified in the abstract",
    "Randomization/blinding procedures not described in the abstract",
    "Outcome reporting relies on modeled decomposition of reaction time; details not provided in the abstract",
    "Single population of young, healthy undergraduate students; generalizability may be limited"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "audio frequency magnetic fields",
    "ELF-VLF",
    "working memory",
    "Sternberg test",
    "reaction time",
    "sham control",
    "transcranial magnetic stimulation"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.25,
      "reason": "Audio-frequency magnetic fields are described as present near audio equipment and acoustic transducers, implying potential exposure in relevant work/usage settings."
    }
  ]
}

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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: 10.3389/fnhum.2023.1135511
PubMed: Not supplied

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