Binaural hearing in the presence of a low frequency magnetic field

The authors propose the binaural auditory system as a candidate neural system that may be disrupted by exposure to relatively weak LF magnetic fields. Extracellular currents, induced by time-varying magnetic fields, may change the timing of action potentials in the auditory nerve, thereby disrupting sound localization when interaural time differences are very small. Three subjects were exposed to a 1,000 Hz magnetic field - with a maximum rate of change of 2.3 T/s at the location of the cochlea - while presenting two identical 1,000 Hz tones randomly delayed to the left or right ear by less than 10 μs. The subjects were asked whether the signal was perceived to be displaced to the left or right side of midline. After a total of over 20,000 trials, conducted at different phase angles between the field signal and the tones, there was no clear evidence for a consistent change in performance when the magnetic field was present. This, however, does not rule out an effect at other combinations of magnetic and acoustic frequencies.