Exposure to alternating electromagnetic fields and effects on the visual and visuomotor systems

Area of Science:

• Neuroscience
• Biophysics
• Medical Imaging

Background:

• Electromagnetic fields (EMFs) are increasingly prevalent, necessitating investigation into their biological effects.
• Magnetic Resonance (MR) imaging utilizes time-varying magnetic field gradients, raising questions about potential acute sensory and motor system impacts.

Purpose of the Study:

• To assess the acute effects of MR imaging-like EMF exposure on visual and visuo-motor systems.
• To evaluate neurobehavioral performance under varying magnetic field gradient strengths.

Main Methods:

• Forty volunteers were exposed to three levels of time-varying magnetic field gradients (0, 10, and 20 mT m(-1)r.m.s.) generated by custom equipment.
• Participants completed a battery of tests assessing visual sensory function (FACT) and visuo-motor performance (Pursuit Aiming II, visual tracking).
• Data were analyzed using linear mixed effects models, with adjustments for confounding factors and jack-knife procedures for variability assessment.

Main Results:

• A trend suggested a 1% reduction in visuo-motor accuracy at high EMF exposure (p=0.06), but not at medium exposure.
• Trends indicated a 12% and 21% improvement in visual contrast sensitivity during medium and high EMF exposure, respectively (p=0.08).
• These observed trends did not reach statistical significance (p<0.05) in the study population.

Conclusions:

• Acute exposure to MR imaging-like EMFs did not produce statistically significant effects on visual or visuo-motor neurobehavioral domains in 40 volunteers.
• Subtle trends suggest potential, though not statistically significant, impacts on visuo-motor accuracy and visual contrast sensitivity.
• Further research with larger cohorts may be warranted to definitively establish the effects of EMF exposure from MR imaging gradient coils.