Direct stimulation of brain functions was studied in this double-blind, placebo-controlled study published in 2013. In this trial, researchers worked with frequencies up to 100 Hz and intensities between 0.4 and 1.4 mT.
Twenty healthy volunteers were enrolled in this double-blind, sham-controlled, crossover study. Thirty minutes of pulsed magnetic field or sham was applied to the head. After one week the other treatment was given. Before and after each treatment, primary and secondary outcomes were measured. Primary outcome was heat pain threshold (HPT) measured with thermal quantitative sensory testing. Other outcomes were warmth detection threshold, and aspects of cognition, emotion and motor performance. As hypothesized heat pain threshold was significantly increased after the pulsed magnetic field stimulation. All other outcomes were unaltered by the pulsed magnetic field but there was a trend level reduction of cognitive performance after pulsed magnetic field stimulation as measured by the digit-symbol substitution task. Results from this pilot study suggest that our device is able to stimulate the brain and to modulate its function. This is in agreement with previous studies that used similar magnetic field strengths to stimulate the brain. Specifically, pain control may be achieved with pulsed magnetic field and for this analgesic effect, coil design does not appear to play a dominant role. In addition, the flexible configuration with small coils on a head cap improves clinical applicability.
Reference: Kortekaas, R. et al. (2013) A Novel Magnetic Stimulator Increases Experimental Pain Tolerance in Healthy Volunteers – A Double-Blind Sham-Controlled Crossover Study. PLoS ONE. 8 (4), 1–7