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Effects of magnetic stray fields from a 7 Tesla MRI scanner on neurocognition: a double-blind randomised crossover study.

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van Nierop LE, Slottje P, van Zandvoort MJE, de Vocht F, Kromkout H. · 2012

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Strong magnetic fields measurably impaired attention and spatial skills in healthy adults, proving brain function can be disrupted by electromagnetic exposure.

Plain English Summary

Summary written for general audiences

Researchers exposed 31 healthy volunteers to magnetic fields from a 7 Tesla MRI scanner while they performed cognitive tests. They found that attention, concentration, and spatial orientation abilities declined significantly when people moved their heads in these strong magnetic fields. The effects were dose-dependent, with stronger magnetic fields causing greater impairment in brain function.

Why This Matters

This study provides compelling evidence that strong magnetic fields can directly impair brain function in real-time. The researchers used the gold standard of study design - a double-blind, randomized crossover trial - and found measurable cognitive deficits at magnetic field strengths of 0.5 and 1.0 Tesla. What makes this particularly significant is that these effects occurred during brief exposure periods, not after long-term exposure. While 7 Tesla MRI scanners represent some of the strongest magnetic fields humans encounter, this research demonstrates that magnetic fields can indeed cross the blood-brain barrier and affect neural processing. The dose-response relationship (stronger fields caused greater impairment) strengthens the case for biological plausibility of EMF effects on the brain. For the broader EMF debate, this study shows that dismissing magnetic field bioeffects as impossible is scientifically unjustified.

Exposure Details

Magnetic Field
0, 500, 1000 mG

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 0, 500, 1000 mGExtreme Concern - 5 mGFCC Limit - 2,000 mGEffects observed in the No Concern range

Study Details

This study characterises neurocognitive domains that are affected by movement-induced time-varying magnetic fields (TVMF) within a static magnetic stray field (SMF) of a 7 Tesla (T) MRI scanner.

Using a double-blind randomised crossover design, 31 healthy volunteers were tested in a sham (0 T),...

Of the six tested neurocognitive domains, we demonstrated that attention and concentration were nega...

Neurocognitive functioning is modulated when exposed to movement-induced TVMF within an SMF of a 7 T MRI scanner. Domains that were affected include attention/concentration and visuospatial orientation. Further studies are needed to better understand the mechanisms and possible practical safety and health implications of these acute neurocognitive effects.

Cite This Study
van Nierop LE, Slottje P, van Zandvoort MJE, de Vocht F, Kromkout H. (2012). Effects of magnetic stray fields from a 7 Tesla MRI scanner on neurocognition: a double-blind randomised crossover study. Occup Environ Med. 2012 Oct;69(10):759-66. doi: 10.1136/oemed-2011-100468. Epub 2012 Aug 27. PMID: 22930737.
Show BibTeX
@article{le_2012_effects_of_magnetic_stray_725,
  author = {van Nierop LE and Slottje P and van Zandvoort MJE and de Vocht F and Kromkout H.},
  title = {Effects of magnetic stray fields from a 7 Tesla MRI scanner on neurocognition: a double-blind randomised crossover study.},
  year = {2012},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/22930737/},
}
PubMed: 22930737

Cited By (60 papers)

View all 60 citing papers on Semantic Scholar

Quick Questions About This Study

Yes, researchers found that 7 Tesla MRI magnetic fields significantly impair cognitive function when people move their heads. A 2012 study showed attention and concentration declined 5-21% per Tesla of exposure, with spatial orientation abilities dropping 47% per Tesla during head movement.
Moving your head in strong magnetic fields can temporarily impair brain function. The 2012 van Nierop study found that head movement within 7 Tesla MRI magnetic fields caused significant declines in attention, concentration, and spatial orientation abilities in healthy volunteers.
7 Tesla MRI scanners can temporarily affect cognitive function during exposure. Research shows these ultra-strong magnetic fields impair attention, concentration, and spatial orientation when patients move their heads, with effects being dose-dependent and stronger at higher field strengths.
7T MRI magnetic fields primarily affect attention, concentration, and spatial orientation abilities. The 2012 study found these cognitive domains were significantly impaired when people moved their heads within the scanner's magnetic field, particularly during high working memory tasks.
Yes, stronger MRI magnetic fields cause greater brain impairment in a dose-dependent manner. Research on 7 Tesla scanners showed cognitive effects increased proportionally with magnetic field strength, with attention declining up to 21% per Tesla of exposure during head movement.