Effect of a 915-MHz simulated mobile phone signal on cognitive function in man.

Abstract

PURPOSE: To examine whether a simulated mobile telephone transmission at 915 MHz has an effect on cognitive function in man. MATERIALS AND METHODS: Thirty-six subjects in two groups were each given two training sessions and then three test sessions in a randomized three-way cross-over design. About 1 W mean power at 915 MHz from a quarter-wave antenna mounted on a physical copy of an analogue phone, as a sine wave, or modulated at 217 Hz with 12.5% duty cycle, or no power, was applied to the left squamous temple region of the subjects while they undertook a series of cognitive function tests lasting approximately 25-30 min. The second group was investigated for sleep, consumption of alcohol and beverages, and any other substances that might affect performance. RESULTS: In both groups, the only test affected was the choice reaction time and this showed as an increase in speed (a decrease in reaction time). There were no changes in word, number or picture recall, or in spatial memory. While an effect of visit-order was evident suggesting a learning effect of repeat tests, the design of the study allowed for this. Additionally, there was no systematic error introduced as a result of consumption of substances or sleep time. CONCLUSIONS: There was evidence of an increase in responsiveness, strongly in the analogue and less in the digital simulation, in choice reaction time. This could be associated with an effect on the angular gyrus that acts as an interface between the visual and speech centres and which lies directly under and on the same side as the antenna. Such an effect could be consistent with mild localized heating, or possibly a non-thermal response, which is nevertheless power-dependent.

AI evidence extraction

Main findings

Across both groups, the only cognitive test affected was choice reaction time, which decreased (faster responses) during exposure conditions; effects were stronger in the analogue simulation and less in the digital simulation. No changes were observed in word, number, or picture recall, or in spatial memory.

Outcomes measured

• Cognitive function tests
• Choice reaction time
• Word recall
• Number recall
• Picture recall
• Spatial memory

Limitations

• Specific absorption rate (SAR) not reported in abstract
• Exposure described as ~1 W mean power at 915 MHz; dosimetry details beyond this not provided in abstract
• Potential learning/visit-order effects noted (though study design reportedly allowed for this)

Suggested hubs

• mobile-phones-rf (0.9)
  Simulated mobile telephone transmission at 915 MHz applied to the temple region during cognitive testing.

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    "exposure": {
        "band": "RF",
        "source": "mobile phone",
        "frequency_mhz": 915,
        "sar_wkg": null,
        "duration": "~25–30 min per cognitive test session; three test sessions in a randomized three-way cross-over design"
    },
    "population": "Human subjects",
    "sample_size": 36,
    "outcomes": [
        "Cognitive function tests",
        "Choice reaction time",
        "Word recall",
        "Number recall",
        "Picture recall",
        "Spatial memory"
    ],
    "main_findings": "Across both groups, the only cognitive test affected was choice reaction time, which decreased (faster responses) during exposure conditions; effects were stronger in the analogue simulation and less in the digital simulation. No changes were observed in word, number, or picture recall, or in spatial memory.",
    "effect_direction": "mixed",
    "limitations": [
        "Specific absorption rate (SAR) not reported in abstract",
        "Exposure described as ~1 W mean power at 915 MHz; dosimetry details beyond this not provided in abstract",
        "Potential learning/visit-order effects noted (though study design reportedly allowed for this)"
    ],
    "evidence_strength": "moderate",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "915 MHz",
        "simulated mobile phone signal",
        "randomized three-way cross-over",
        "quarter-wave antenna",
        "217 Hz modulation",
        "cognitive function",
        "choice reaction time",
        "memory",
        "localized exposure"
    ],
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