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Effects of 7 Hz-modulated 450 MHz electromagnetic radiation on human performance in visual memory tasks.

Bioeffects Seen

Lass L, Tuulik V, Ferenets CR, Riisalo R, Hinrikus H. Effects of 7 Hz-modulated 450 MHz electromagnetic radiation on human performance in visual memory tasks. Int. J. Rad. Biol. 78: 937-944, 2002. · 2002

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Brief exposure to cell phone-level RF radiation altered attention and memory performance in 100 volunteers, proving cognitive effects below safety limits.

Plain English Summary

Summary written for general audiences

Researchers exposed 100 volunteers to low-level 7 Hz-modulated radio frequency radiation (similar to older cell phone frequencies) for 10-20 minutes and tested their attention and memory skills. The exposed group showed increased variability in error rates on two attention tasks, while surprisingly performing better on one memory task. This suggests that even brief, low-level RF exposure can measurably alter cognitive performance in complex ways.

Why This Matters

This study adds important evidence to our understanding of how RF radiation affects the brain at exposure levels well below current safety limits. The power density used (0.158 mW/cm²) is comparable to what you might experience from a cell phone held at arm's length, yet it produced measurable changes in cognitive performance within just 10-20 minutes. What makes this research particularly significant is the mixed nature of the effects - some cognitive functions showed impairment while others actually improved, suggesting RF radiation doesn't simply 'damage' the brain but rather disrupts its normal functioning in complex ways. The fact that researchers found these effects in a well-controlled study of 100 people strengthens the evidence that our brains are sensitive to RF radiation at levels the wireless industry considers completely safe.

Exposure Details

Power Density
0.158 µW/m²
Source/Device
7 Hz-modulated 450 MHz
Exposure Duration
10-20 min

Exposure Context

This study used 0.158 µW/m² for radio frequency:

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextA logarithmic scale showing exposure levels relative to Building Biology concern thresholds and regulatory limits.Study Exposure Level in ContextThis study: 0.158 µW/m²Extreme Concern1,000 uW/m2FCC Limit10M uW/m2Effects observed in the Slight Concern range (Building Biology)FCC limit is 63,291,139x higher than this exposure level

Study Details

The aim was to examine low-level 7 Hz-modulated 450 MHz radiation effects on human performance in visually presented neuropsychological tasks associated with attention and short-term memory.

A homogeneous group of 100 subjects (37 female, 63 male) were randomly assigned to either the expose...

The results of tasks 1 and 3 showed a significant increase in variances of errors (p<0.05) in the ex...

The data provide additional evidence that acute low-level exposure to microwaves modulated at 7 Hz can affect cognitive processes such as attention and short-term memory.

Cite This Study
Lass L, Tuulik V, Ferenets CR, Riisalo R, Hinrikus H. Effects of 7 Hz-modulated 450 MHz electromagnetic radiation on human performance in visual memory tasks. Int. J. Rad. Biol. 78: 937-944, 2002. (2002). Effects of 7 Hz-modulated 450 MHz electromagnetic radiation on human performance in visual memory tasks. Int. J. Rad. Biol. 78: 937-944, 2002.
Show BibTeX
@article{l_2002_effects_of_7_hzmodulated_1141,
  author = {Lass L and Tuulik V and Ferenets CR and Riisalo R and Hinrikus H. Effects of 7 Hz-modulated 450 MHz electromagnetic radiation on human performance in visual memory tasks. Int. J. Rad. Biol. 78: 937-944 and 2002.},
  title = {Effects of 7 Hz-modulated 450 MHz electromagnetic radiation on human performance in visual memory tasks.},
  year = {2002},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/12465659/},
}

Quick Questions About This Study

Researchers exposed 100 volunteers to low-level 7 Hz-modulated radio frequency radiation (similar to older cell phone frequencies) for 10-20 minutes and tested their attention and memory skills. The exposed group showed increased variability in error rates on two attention tasks, while surprisingly performing better on one memory task. This suggests that even brief, low-level RF exposure can measurably alter cognitive performance in complex ways.