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Effects of pulsed and continuous wave 902 MHz mobile phone exposure on brain oscillatory activity during cognitive processing.

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Krause CM, Pesonen M, Haarala Bjornberg C, Hamalainen H. · 2007

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Cell phone radiation subtly alters brain wave patterns during use, even when cognitive performance appears unaffected.

Plain English Summary

Summary written for general audiences

Finnish researchers exposed 72 men to cell phone radiation at 902 MHz while they performed memory tasks, measuring brain wave activity through EEG recordings. The study found that phone radiation caused subtle changes in brain oscillations (electrical activity patterns) in the alpha frequency range, though these effects were inconsistent and didn't affect actual task performance. This adds to growing evidence that cell phone radiation can influence brain activity, even when users don't notice any immediate behavioral changes.

Why This Matters

This study represents an important piece of the puzzle in understanding how cell phone radiation affects our brains. The researchers found measurable changes in brain wave patterns during exposure to 902 MHz radiation, the same frequency used by many mobile phones. What makes this particularly significant is that these neural changes occurred without any noticeable impact on cognitive performance, suggesting our brains may be responding to EMF in ways we don't consciously perceive. The inconsistent nature of the effects the researchers observed actually mirrors what we see across much of the EMF research landscape. This variability doesn't invalidate the findings, but rather points to the complex ways electromagnetic fields interact with biological systems. The reality is that our brains operate on electrical signals, so it's entirely plausible that external electromagnetic fields would influence this activity. What this means for you is that your phone may be subtly altering your brain's electrical patterns during use, even when you feel completely normal.

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 12 Hz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 12 HzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study. The study examined exposure from: 8-12 Hz

Study Details

The aim of the current double-blind studies was to partially replicate the studies by Krause et al. [2000ab, 2004] and to further investigate the possible effects of electromagnetic fields (EMF) emitted by mobile phones (MP) on the event-related desynchronisation/synchronisation (ERD/ERS) EEG (electroencephalogram) responses during cognitive processing.

Two groups, both consisting of 36 male participants, were recruited. One group performed an auditory...

In line with our previous studies, we observed that the exposure to EMF had modest effects on brain ...

We conclude that the effects of EMF on brain oscillatory responses may be subtle, variable and difficult to replicate for unknown reasons

Cite This Study
Krause CM, Pesonen M, Haarala Bjornberg C, Hamalainen H. (2007). Effects of pulsed and continuous wave 902 MHz mobile phone exposure on brain oscillatory activity during cognitive processing. Bioelectromagnetics.28(4):296-308, 2007.
Show BibTeX
@article{cm_2007_effects_of_pulsed_and_2311,
  author = {Krause CM and Pesonen M and Haarala Bjornberg C and Hamalainen H.},
  title = {Effects of pulsed and continuous wave 902 MHz mobile phone exposure on brain oscillatory activity during cognitive processing.},
  year = {2007},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/17203478/},
}
PubMed: 17203478

Cited By (82 papers)

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Quick Questions About This Study

Finnish researchers found that 902 MHz cell phone radiation caused subtle changes in brain wave patterns (alpha frequency range 8-12 Hz) during memory tasks in 72 men. However, these brain wave changes were inconsistent and didn't affect actual memory performance on the tasks.
A 2007 study tested both pulsed and continuous wave 902 MHz radiation during cognitive tasks. Both types caused modest changes in brain oscillations, but the effects were variable and inconsistent, making it difficult to determine if one type impacts brain activity more than the other.
Research shows that 902 MHz radiation effects on brain oscillations are subtle, variable and difficult to replicate for unknown reasons. The 2007 Finnish study found inconsistent results even within their own research, highlighting the challenge of reproducing EMF brain effects consistently.
No, brain wave changes from 902 MHz cell phone radiation don't appear to affect cognitive performance. The Finnish study found that while radiation altered brain oscillations in the alpha frequency range, participants showed no changes in their actual memory task performance.
Cell phone radiation at 902 MHz primarily affects brain oscillations in the alpha frequency range (approximately 8-12 Hz). Finnish researchers consistently observed these effects across multiple studies, though the changes remain modest and don't impact behavioral performance on cognitive tasks.