Pain relief using different doses of pulsed magnetic therapy was tested in the clinical study with the assistance of functional magnetic resonance imaging (fMRI). Pulsed magnetic fields of various intensities and frequencies of 1, 3, 5 and 9 Hz were used on 47 volunteers who experienced induced acute thermal pain.
Forty-seven participants were recruited, and pulsed magnetic field was applied through the MRI gradient system using a novel technique. Regions of interest (ROIs) matching those of previous studies were examined for a potential dose response. Significant correlations between applied field strength and change in BOLD activity were found in the anterior cingulate and the ipsilateral insula, indicating that there might be either a dose response or a threshold effect of the low frequency pulsed magnetic field.
Reference: Robertson, J. A. et al. (2010) Evidence for a dose-dependent effect of pulsed magnetic fields on pain processing. Neuroscience Letters. [Online] 482 (2), 160–162.